PATENT ABSTRACT
A liquid container, comprising: a housing containing therein liquid; a liquid supply opening formed in the housing for withdrawing the liquid from the housing; a liquid sensor mounted on the housing for detecting a level of the liquid which is variable in accordance with a consumption of the liquid; and a first partition wall extending in an interior of the housing and defining the interior of the housing into at least two liquid accommodating chambers which communicate with each other, the liquid accommodating chambers comprising: an air-communication side liquid accommodating chamber which communicates with ambient air; and a detection side liquid accommodating chamber in which the liquid sensor is disposed at an upper portion thereof.

PATENT DESCRIPTION
This is a divisional of Application Ser. No. 10/243,730 filed Sep. 16, 2002, which in turn is a divisional of Application Ser. No. 09/574,012 filed May 19, 2000 now U.S. Pat. No. 6,536,861, the disclosures of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a liquid container equipped with a piezoelectric apparatus therein which detects the consumption state of liquid inside a liquid container which houses the liquid. More particularly, the present invention relates to the liquid container equipped with a piezoelectric apparatus that detects liquid consumption status in a liquid container which provides liquid to a recording head of an ink-jet recording apparatus. 
   2. Description of the Related Art 
   An ink cartridge mounted on an ink-jet type recording apparatus is taken as an example of a liquid container and is described below. In general, an ink-jet recording apparatus comprises: a carriage equipped with an ink-jet type recording head comprised of a pressure generating means which compresses a pressure generating chamber and a nozzle opening which discharges the compressed ink from a nozzle opening in the form of ink droplets; and an ink tank which houses ink supplied to the recording head through a passage, and is structured such that the printing operation can be performed continuously. In general, the ink tank is structured as a cartridge that can be detached from the recording apparatus, so that a user can easily replace it at the time when the ink is used up. 
   Conventionally, as a method of controlling the ink consumption of the ink cartridge, a method is known of controlling the ink consumption by means of a calculation in which the counted number of ink droplets discharged by the recording head and the amount of ink sucked in a maintenance process of the printing head are integrated by software, and another method of controlling the ink consumption in which the time at which the ink is actually consumed is detected by directly mounting to the ink cartridge two electrodes for use in detecting the liquid surface, and so forth. 
   However, in the calculation-based method of controlling the ink consumption by integrating the discharged number of ink droplets and the amount of ink or the like by the software, the pressure inside the ink cartridge and the viscosity of the ink change depending on usage environment such as ambient temperature and humidity, elapsed time after an ink cartridge has been opened for use, and usage frequency at a user side. Thus, a problem is caused where a considerable error occurs between the calculated ink consumption and the actual ink consumption. Moreover, another problem is caused in which the actual amount of ink remaining is not known because once the same cartridge is removed and then mounted again, the integrated counted value is reset. 
   On the other hand, in the method of controlling by electrodes the time at which the ink is consumed, the remaining amount of ink can be controlled with high reliability since the actual ink consumption can be detected at one point. However, in order that the liquid surface of the ink can be detected, the ink need be conductive, so suitable types of ink for use are very limited. Moreover, a problem is caused in that a fluid-tight structure between the electrodes and the cartridge might be complicated. Moreover, since precious metal is usually used as the electrode material, which is highly conductive and erosive, manufacturing costs of the ink cartridge increases thereby. Moreover, since it is necessary to attach the two electrodes to two separate positions of the ink cartridge, the manufacturing process increases, thus causing a problem which increases the manufacturing costs. 
   Moreover, when managing the ink consumption status by mounting a piezoelectric device on the ink cartridge, ink inside the ink cartridge may roll or bubble by the scanning of the ink cartridge during the printing operation. By the waving or bubbling of ink nearby the piezoelectric device, ink or bubble of ink attaches to the piezoelectric device. Then, there is a cases arises that the piezoelectric device cannot detect the ink consumption quantity by the ink or bubble of ink attached to the piezoelectric device. In other words, even there is only small amount of ink inside the ink cartridge, if the ink attaches to the piezoelectric device mistakenly by the waving of ink, there is a danger that the piezoelectric device detects mistakenly that there is still enough ink inside the ink cartridge. Moreover, if the bubble attaches to the piezoelectric device, there is danger that the piezoelectric device detects mistakenly that there is no ink inside the ink cartridge even if the ink cartridge  180  is filled by ink. 
   Furthermore, there is problem that the position of mounting the piezoelectric device on the ink cartridge is limited for detecting the ink end status inside the ink cartridge. For example, if mounting the piezoelectric device on the wall at the lower side of the ink surface, the piezoelectric device can detect the ink end. On the other hand, if mounting the piezoelectric device on the wall at the upper side of the ink surface, the piezoelectric device cannot detect the ink end. 
   SUMMARY OF THE INVENTION 
   Therefore, it is an object of the present invention to provide a liquid container capable of reliably detecting a liquid consumption status and dispensing with a complicated sealing structure. 
   Moreover, it is another object of the present invention to prevent the waving or bubbling of liquid around the piezoelectric device inside the liquid container. 
   Furthermore, it is still another object of the present invention to provide a liquid container, the piezoelectric device of which can reliably detect a liquid consumption status by detecting the liquid surface even in the case that liquid inside the liquid container rolls and bubbles. 
   Furthermore, it is still another object of the present invention to provide a liquid container, the piezoelectric device of which can reliably detect a liquid consumption status even in the case that the liquid container tilts or fell down because the gas does not contacts with the piezoelectric device. 
   Furthermore, it is still another object of the present invention to provide a liquid container capable of reliably detecting a liquid consumption status in the liquid container even if the piezoelectric device is mounted on the upper side of the liquid surface in the liquid container. 
   Furthermore, it is still another object of the present invention to provide a liquid container which does not need to be mounted on the accurate position, in other words, the mounting position of the piezoelectric device on the liquid container can be freely designed. 
   These objects are achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention. 
   According to an aspect of the present invention, there is provided a liquid container which may comprise: a housing containing therein liquid; a liquid supply opening formed in the housing for withdrawing the liquid from the housing; a liquid sensor mounted on the housing for detecting a level of the liquid which is variable in accordance with a consumption of the liquid; and a first partition wall extending in an interior of the housing and defining the interior of the housing into at least two liquid accommodating chambers which communicate with each other, the liquid accommodating chambers comprising: an air-communication side liquid accommodating chamber which communicates with ambient air; and a detection side liquid accommodating chamber in which the liquid sensor is disposed at an upper portion thereof. 
   The liquid container may further comprises a porous member accommodated within the detection side liquid accommodating chamber. The liquid supply opening may be formed in the air-communication side liquid accommodating chamber. The liquid supply opening may be formed in the detection side liquid accommodating chamber. A volume of the air-communication side liquid accommodating chamber may be different from that of the detection side liquid accommodating chamber. The volumes of the at least two liquid accommodating chambers may decrease from one side wall of the housing to the other opposite wall. 
   The liquid container may further comprising a second partition wall extending in the detection side liquid accommodating chamber and defining at least two small detection chambers. The second partition wall may be formed with a liquid communication opening at a lower part thereof. The second partition wall may be formed with a liquid communication opening at an upper part thereof. The detection sensor may be disposed on each of the small detection chambers. The volumes of the small detection chambers may be different from each other. The volumes of the at least two small detection chambers may decrease from one side wall of the housing to the other opposite wall. 
   The detection side liquid accommodating chamber may generate no capillary force for holding the liquid. The small detection chamber may generate no capillary force for holding the liquid. The detection side liquid accommodating chamber may comprise a recessed part formed at a top wall thereof. The liquid sensor may comprise a cavity which opens toward an interior of the housing for holding the liquid. The liquid sensor may comprise a piezoelectric device having a vibrating section, the vibrating section generates a counter electromotive force in accordance with a residual vibration of the vibrating section. 
   The liquid sensor may detect at least an acoustic impedance of the liquid and detects a liquid consumption status in accordance with the acoustic impedance. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening. The volume of the detection side liquid accommodating chamber may be equal to or less than half the volume of the air-communication side liquid accommodating chamber. The volumes of the liquid accommodating chambers may decrease from one side wall of the housing to the other opposite wall. 
   The porous member may comprise a first porous material disposed close to the liquid sensor and a second porous material disposed far from the liquid sensor compared with the first porous material, and the second porous material has a higher liquid-philic characteristics than the first porous material. The liquid sensor may comprise a piezoelectric device having a vibrating section, the vibrating section generates a counter electromotive force in accordance with a residual vibration of the vibrating section. The liquid sensor may detect at least an acoustic impedance of the liquid and detects a liquid consumption status in accordance with the acoustic impedance. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which-ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening. 
   According to another aspect of the present invention, there is provided a liquid container which may comprise: a housing containing therein liquid; a liquid supply opening supplying liquid to an exterior of the housing; a detection device mounted on the housing, the detection device comprising a piezoelectric element for detecting a liquid consumption status; and a wave absorbing wall extending in an interior of the housing disposed at a place facing the detection device. A gap may be defined between the detection device and the wave absorbing wall. The gap may not generate a capillary force for holding the liquid. 
   The gap may generate a capillary force which is smaller than a force for holding the liquid. The detection device may comprise a cavity for receiving and holding liquid, the cavity being formed to open toward the interior of the housing. The wave absorbing wall may be secured to and extends from an interior wall of the housing. The detection device may be attached to a first wall of the housing which extends in a vertical direction of the liquid level, and the wave absorbing wall may extend in parallel with the first wall of the housing. 
   The detection device may be attached to a bottom wall of the housing, and the wave absorbing wall may extend in parallel with the liquid level. The wave absorbing wall may extend in an inclined direction with respect to the liquid level. The wave absorbing wall may extend from a side wall of the housing which is perpendicular to the liquid level. The a capillary force may be generated between at least a part of the internal wall and an inner wall of the housing. The wave absorbing wall may comprise a bending section which is formed by bending at least a part of an edge of the wave absorbing wall toward a wall on which the detection device is mounted, and a gap defined by the bending section and the detection device generates a capillary force while a gap defined by the wave absorbing wall and the detection device does not generate a capillary force. 
   The wave absorbing wall may comprise a plurality of wave absorbing wall pieces, and at least one of the plurality of wave absorbing wall pieces may extend from a side wall of the housing which is perpendicular to the liquid level. The detection device may comprise a vibrating section which generates a counter electromotive force in accordance with a residual vibration of the vibrating section. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container may supply the liquid contained therein to the printhead through the liquid supply opening. 
   According to the other aspect of the present invention, there is provided a liquid container may comprise: a housing containing therein liquid; a liquid supply opening formed in a wall of the housing for withdrawing the liquid to an exterior; a detection device mounted on the housing, the detection device comprising a piezoelectric element for detecting a liquid consumption status; and a porous member disposed within the housing in the vicinity of the detection device. The detection device may contact the porous member. A gap may be defined between the porous member and the detection device. 
   The detection device may comprise a cavity and a vibrating section which contacts the liquid through the cavity, and the porous member is disposed in the cavity. A capillary force of the porous member may be smaller than a force which holds the liquid. The detection device may comprise a base plate, a vibrating portion and a through hole formed in the base plate, and the porous member covers at least a part of the through hole. The detection device may further comprise a groove connecting with the through hole, and the porous member is disposed on the groove. The detection device and the porous member may be disposed on a plane where the liquid supply opening is formed. 
   The detection device may comprise a vibrating section which generates a counter electromotive force in accordance with a residual vibration of the vibrating section, and the detection device detects the liquid consumption status in accordance with the counter electromotive force. The detection device may comprise a piezoelectric element and a mounting structure unitarily formed with the piezoelectric element, and the mounting structure is attached to the housing. The liquid container may be mounted on an ink-jet printing apparatus having a printhead which ejects ink droplets, and the liquid container supplies the liquid contained therein to the printhead through the liquid supply opening. 
   This summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the above described features. The above and other features and advantages of the present invention will become more apparent from the following description of embodiments taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1(A) and 1(B)  show a side cross sectional view of an embodiment of the ink cartridge according to the present invention. 
       FIG. 2  shows a side cross sectional view of the other embodiment of the ink cartridge according to the present invention. 
       FIGS. 3(A) and 3(B)  show a side cross sectional view of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 4  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIGS. 5(A) and 5(B)  show a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIGS. 6(A) and 6(B)  show a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIGS. 7(A) and 7(B)  show a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 8  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 9  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 10  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 11  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 12  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 13  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
       FIG. 14  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. 
       FIG. 15  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. 
       FIG. 16  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. 
       FIG. 17  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. 
       FIG. 18  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 1 . 
       FIG. 19  is a detailed cross sectional view of a subtank unit  33  as an embodiment of the liquid container according to the present invention. 
       FIG. 20  is a cross sectional view of another embodiment of a subtank unit  33  of the liquid container according to the present invention. 
       FIG. 21  is a cross sectional view of further another embodiment of a subtank unit  33  of the liquid container according to the present invention. 
       FIGS. 22(A) to 22(C)  show a detail and equivalent circuit of an actuator  106 , which is an embodiment of the piezoelectric device of the present invention. 
       FIGS. 23(A) to 23(F)  show a detail and equivalent circuit of an actuator  106 , which is an embodiment of the piezoelectric device of the present invention. 
       FIGS. 24(A) and 24(B)  are graphs which show the relationship between the ink quantity inside the ink tank and the resonant frequency fs of the ink and the vibrating section. 
       FIGS. 25(A) and 25(B)  show a waveform of the residual vibration of the actuator  106  and the measuring method of the residual vibration. 
       FIG. 26  shows the manufacturing method of the actuator  106 . A plurality of the actuators  106 , four numbers in the case of the  FIG. 26 , are formed as one body. 
       FIG. 27  shows a cross-section of a part of the actuator  106 . 
       FIG. 28  shows a cross-section of the actuator  106 . 
       FIG. 29  shows the manufacturing method of the actuator  106  shown in  FIG. 26 . 
       FIG. 30  shows the further other embodiment of the ink cartridge of the present invention. 
       FIGS. 31(A) to 31(C)  show further other embodiment of the ink cartridge of the present invention. 
       FIGS. 32(A) to 32(C)  show other embodiment of the through hole  1   c.    
       FIGS. 33(A) and 33(B)  are slant views of the further other embodiment of the actuator. 
       FIG. 34  shows a slant view of the other embodiment of the actuator. 
       FIGS. 35(A) to 35(C)  show plan views of the through hole  1   c  according to another embodiment. 
       FIG. 36  shows a slant view of the configuration that forms the actuator  106  in one body as a mounting module  100 . 
       FIG. 37  shows an exploded view of the module  100  shown in  FIG. 36  to show the structure of the module  100 . 
       FIG. 38  shows the slant view of the other embodiments of the module. 
       FIG. 39  shows an exploded view of the module  400  shown in  FIG. 38  to show the structure of the module  400 . 
       FIG. 40  shows the further other embodiment of the module. 
       FIG. 41  shows a cross-sectional view around the bottom of the container  1  when the module  100  shown in  FIG. 36  is mounted on the container  1 . 
       FIGS. 42(A) to 42(C)  show the cross section of the ink container when mounting module  700 B on the container  1 . 
       FIG. 43  shows an embodiment of an ink cartridge and an ink jet recording apparatus which uses the actuator  106  shown in  FIG. 22 . 
       FIG. 44  shows a detail around the head member of the ink jet recording apparatus. 
       FIGS. 45(A) and 45(B)  show other embodiment of the ink cartridge  180  shown in  FIG. 44 . 
       FIGS. 46(A) to 46(C)  show further other embodiment of the ink cartridge  180 . 
       FIGS. 47(A) and 47(B)  show further other embodiment of the ink cartridge  180 . 
       FIGS. 48(A) to 48(D)  show further other embodiment of the ink cartridge  180 . 
       FIG. 49  shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. 
       FIG. 50  shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. 
       FIGS. 51(A) to 51(D)  show other embodiment of the ink cartridge using the actuator  106 . 
       FIG. 52  is a cross sectional view of an embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. 
       FIG. 53  is a perspective view of the ink cartridge which stores plural types of inks, viewed from an outside thereof, according to an embodiment. 
       FIG. 54  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 52  and  FIG. 53 . 
       FIG. 55  is a cross sectional view of an another embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. 
       FIG. 56  shows further other embodiment of the ink cartridge using the actuator  106 . 
       FIG. 57  shows further another embodiment of the ink cartridge using the actuator  106 . 
       FIG. 58  shows further another embodiment of the ink cartridge  180 . 
       FIG. 59  shows further another embodiment of the ink cartridge  180 . 
       FIG. 60  shows further another embodiment of the ink cartridge  180 . 
       FIG. 61  shows further another embodiment of the ink cartridge  180 . 
       FIG. 62  shows further another embodiment of the ink cartridge  180 . 
       FIG. 63  shows further another embodiment of the ink cartridge  180 . 
       FIG. 64  shows further other embodiment of the ink cartridge  180 . 
       FIG. 65  shows further other embodiment of the ink cartridge  180 . 
       FIG. 66  shows further other embodiment of the ink cartridge  180 . 
       FIG. 67  shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator  106 . 
       FIG. 68  shows a detail around the head member of the ink jet recording apparatus. 
       FIG. 69  is a cross sectional view of an embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. 
       FIG. 70  is a cross sectional view of an embodiment of an ink jet recording apparatus and ink cartridge according to the present invention. 
       FIG. 71  is a cross sectional view of a further another embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. 
       FIG. 72  shows further another embodiment of the ink cartridge using the actuator  106 . 
       FIG. 73  shows further another embodiment of the ink cartridge using the actuator  106 . 
       FIG. 74  shows further another embodiment of the ink cartridge using the actuator  106 . 
       FIG. 75  shows a cross section of an ink cartridge  180 D which is further other embodiment of the ink cartridge  180  using actuator  106 . 
       FIGS. 76(A) and 76(B)  show further another embodiment of the ink cartridge using actuator  106 . 
       FIG. 77  shows further another embodiment of the ink cartridge using actuator  106 . 
       FIG. 78  shows further another embodiment of the ink cartridge using the actuator  106 . 
       FIG. 79  shows further another embodiment of the ink cartridge  180 . 
       FIG. 80  shows further another embodiment of the ink cartridge  180 . 
       FIG. 81  shows further another embodiment of the ink cartridge  180 . 
       FIG. 82  shows further another embodiment of the ink cartridge  180 . 
       FIG. 83  shows further another embodiment of the ink cartridge  180 . 
       FIG. 84  shows further another embodiment of the ink cartridge  180 . 
       FIG. 85  shows further other embodiment of the ink cartridge using the actuator  106 . 
       FIG. 86  shows further other embodiment of the ink cartridge  180 . 
       FIG. 87  shows further other embodiment of the ink cartridge  180 . 
       FIG. 88  shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator  106 . 
       FIG. 87  shows further other embodiment of the ink cartridge  180 . 
       FIG. 88  shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator  106 . 
       FIG. 89  shows a detail around the head member of the ink jet recording apparatus. 
       FIG. 90  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink. 
       FIG. 91  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 90 . 
       FIG. 92  is a detailed cross sectional view of a subtank unit  33 . 
       FIGS. 93(A) and 93(B)  are cross sectional views showing another embodiment of the ink cartridge. 
       FIGS. 94(I)  to (V) show manufacturing methods of the elastic wave generating device  3 ,  15 ,  16  and  17 . 
       FIG. 95  shows manufacturing methods of the elastic wave generating device  3 ,  15 ,  16  and  17 . 
       FIG. 96  shows an ink cartridge according to another embodiment of the present invention. 
       FIG. 97  shows ink cartridges according to still another embodiments of the present invention. 
       FIG. 98  shows ink cartridges according to still another embodiments of the present invention. 
       FIG. 99  shows an ink cartridge according to still another embodiment of the present invention. 
       FIG. 100  shows a cross section of the ink-jet recording apparatus alone. 
       FIG. 101  is a cross section of the ink-jet recording apparatus to which the ink cartridge  272  is mounted. 
       FIG. 102  shows an embodiment of the ink cartridge for use with a single color, for instance, the black color. 
       FIG. 103  shows an ink cartridge  272  according to still another embodiment of the present invention. 
       FIG. 104  shows an ink cartridge  272  and an ink-jet recording apparatus according to still another embodiment of the present invention. 
       FIG. 105  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink. 
       FIGS. 106(A) and 106(B)  are cross sectional views of the bottom part of the ink cartridge of the present embodiment. 
       FIG. 107  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 105  and  FIG. 106 . 
       FIG. 108  is a cross sectional view of another embodiment of a subtank unit  33 . 
       FIG. 109  show ink cartridges according to still another embodiments of the present invention. 
       FIG. 110  shows an ink cartridge according to still another embodiment of the present invention. 
       FIGS. 111(A) to 111(C)  show other embodiment of the through hole  1   c.    
       FIG. 112  is a slant view of the further other embodiment of the actuator. 
       FIG. 113  shows a further embodiment of the ink cartridge  180 . 
       FIG. 114  shows further other embodiment of the ink cartridge  180 . 
       FIGS. 115(A) to 115(C)  show further other embodiment of the ink cartridge  180 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention will now be described based on the preferred embodiments, which do not intend to limit the scope of the present invention, but exemplify the invention. All of the features and the combinations thereof described in the embodiment are not necessarily essential to the invention. 
   The basic concept of the present invention is to detect a state of the liquid inside a liquid container by utilizing vibration phenomena. The state of the liquid includes whether or not the liquid in the liquid container is empty, amount of the liquid, level of the liquid, types of the liquid and combination of liquids. Several specific methods realizing for detection of the state of the liquid inside the liquid container utilizing vibration phenomena are considered. For example, a method is considered in which the medium and the change of its state inside the liquid container are detected in such a manner that an elastic wave generating device generates an elastic wave inside the liquid container, and then the reflected wave which is thus reflected by the liquid surface or a wall disposed counter thereto is captured. There is another method in which a change of acoustic impedance is detected by vibrating characteristics of a vibrating object. 
   As a method utilizing the change of the acoustic impedance, a vibrating portion of a piezoelectric device or an actuator having a piezoelectric element therein is vibrated. Thereafter, a resonant frequency or an amplitude of the back electromotive force waveform is detected by measuring the back electromotive force which is caused by residual vibration which remains in the vibrating portion, so as to detect the change of the acoustic impedance. As another method utilizing the change of the acoustic impedance, the impedance characteristic or admittance characteristic of the liquid is measured by a measuring apparatus such as an impedance analyzer and a transmission circuit, so that the change of a current value or a voltage value, or the change of the current value or voltage value due to the frequency caused by the vibration given to the liquid is measured. 
   In the present embodiment, the medium in the liquid container and the change of the status of the medium in the liquid container is detected using the piezoelectric device or actuator to detect the residual vibration remained in the vibrating section of the piezoelectric device and the actuator. 
     FIG. 1  to  FIG. 13  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink as an embodiment of the liquid container according to the present invention. An ink cartridge according to the present embodiment comprises a container  1  which contains liquid K, a ink supply port  2  which supplies liquid K outside the container  1 , an actuator  106  which detects ink consumption status inside the container  1 , and a wave preventing wall which provided at the position that faced to the actuator  106 . 
   A packing ring  4  and a valve body  6  are provided in the ink supply port  2 . Referring to  FIG. 18 , the packing ring  4  is engaged with the ink supply needle  32  communicating with a recording head  31 , in a fluid-tight manner. The valve body  6  is constantly and elastically contacted against the packing ring  4  by way of a spring  5 . When the ink supply needle  32  is inserted, the valve body  6  is pressed by the ink supply needle  32  so as to open an ink passage, so that ink inside the container  1  is supplied to the recording head  31  via the ink supply port  2  and the ink supply needle  32 . On an upper wall of the container  1 , there is mounted a semiconductor memory means  7  which stores data on ink inside the ink cartridge. 
     FIG. 1(A)  shows a side cross sectional view of an embodiment of the ink cartridge according to the present invention. In  FIG. 1  to  FIG. 4 , the wave preventing wall  1192   a  to  1192   d  is extended horizontally to the ink surface. Furthermore, the actuator  106  is mounted on the bottom face  1   a  which is located lower side of the ink surface. As shown in  FIG. 1(A) , the ink supply port  2  that engages with the ink supply needle of the recording apparatus is provided on the container  1  which contains ink. The actuator  106  is mounted on the outside the bottom face  1   a  of the container  1  so that the actuator  106  can contacts with ink inside the container  1  through the through hole  1   c  which is provided on he container  1 . The actuator  106  is provided on the position which is higher than the ink supply port  2  so that when ink K is almost used up, that is, at the time of the ink near end, the propagation of the elastic wave can change from ink to gas. The actuator  106  can be used as only for the means of merely detecting the vibration generated in the ink cartridge without generating a vibration by itself. 
     FIG. 1(B)  shows a cross sectional view from the front of an embodiment of the ink cartridge according to the present embodiment. As shown in  FIG. 1(B) , the container  1  has a side wall  1020  which extends substantially vertical direction to the liquid surface. The wave preventing wall  1192   a  is fixed to the container  1  by mounting on the side wall  1020  of the container  1 . 
   A gap is provided between the actuator  106  and the wave preventing wall  1192   a . If ink is filled in the ink cartridge, ink is filled in the gap between the actuator  106  and the wave preventing wall  1192   a . On the other hand, the gap is designed such that ink is not held in the gap between the actuator  106  and the wave preventing wall  1192   a  if ink in the ink cartridge is used up. In other words, no capillary force for holding ink arises between the actuator  106  and the wave preventing wall  1192   a.    
   Because the through hole  1   c  is provided on the container  1 , ink remains in the through hole  1   c  even the ink inside the container  1  is consumed. Therefore, even when the ink cartridge vibrates by such as scanning operation during the printing process and thus ink nearby the ink supply port  2  rolls, ink does not mistakenly attach to the actuator  106  because ink previously remains in the through hole  1   c . Thus, there is only little possibility for the actuator  106  to mistakenly detect the existence of ink. 
   The wave preventing wall is provided to face to the actuator  106  in the ink cartridge according to the present embodiment. Therefore, even ink nearby the ink supply port  2  rolls, the wave preventing wall prevents the rolled ink to be contact with the actuator  106 . Therefore, Thus, there is only little possibility for the actuator  106  to mistakenly detect the existence of ink. 
   Furthermore, bubbles may be generated by the waving of ink, which is caused by the vibration of ink cartridge generated by such as the scanning operation during the printing process. Then, there is danger that the actuator  106  may detect mistakenly that there is no ink if the bubble attaches to the actuator  106  even if the ink is filled in the container  1 . However, according to the configuration of the present embodiment, the wave preventing wall prevents the waving of ink around the piezoelectric device even when the ink cartridge vibrates by such as the scanning operation during the printing process. By preventing the waving of ink around the piezoelectric device, the wave preventing wall prevents the generation of the bubbles. Furthermore, even the bubbles generate, the wave preventing wall prevents the bubbles to move close to the actuator  106  and contact with the actuator  106  because the wave preventing wall is provided such that the wave preventing wall faces to the actuator  106 . 
   There is no limitation of the size, shape, flexibility, and material for the wave preventing wall. Therefore, the size of the wave preventing wall can be made further larger or can be made further smaller. The thickness of the wave preventing wall can be made further thicker or can be made further thinner. Furthermore, the shape of the wave preventing wall can be square, rectangular, polygon, or an ellipse. Furthermore, the wave preventing wall can be made from the hard material or flexible material. Furthermore, the wave preventing wall can be made from the air-tight or liquid-tight material. Conversely, the wave preventing wall can be made from the breathability material or material which can pas through liquid. As an example of the air-tight or liquid-tight material, there are plastic, tefron, nylon, polypropylene, or PET. On the other hand, as an example of the breath ability material or a material which pass through liquid, there are porous material constituted by such as nylon or a material having a mesh structure. Furthermore, the porous material used for the wave preventing wall can be negative pressure generating member. 
   Preferably, the container  1  and the wave preventing wall is formed by a same material such that both of the container  1  and the wave preventing wall can be formed as one body. Then, the manufacturing process of the ink cartridge can be reduced. 
   Because ink cannot be supplied from the ink supply port  2  to the recording head if the pressure inside the ink cartridge becomes extremely negative with the ink consumption, airhole, not shown in figure, is provided on a part of the container so that the pressure inside the ink cartridge does not become extreme negative. 
     FIG. 2  shows a side cross sectional view of the other embodiment of the ink cartridge according to the present invention. As shown in  FIG. 2 , a wave preventing wall  1192   b  is mounted on the side wall  1030  which extends to the vertical direction to the ink surface. The cross section viewed from the front of the ink cartridge according to the present embodiment is same as the cross section shown in one of  FIG. 1(B)  or  FIG. 3(B) . 
   The wave preventing wall  1192   b  of the ink cartridge of the present embodiment extends longer than the wave preventing wall  1192   a  of the embodiment shown in  FIG. 1 . Therefore, the wave preventing wall  1192   b  can effectively protects the actuator  106  from the wave of ink. 
     FIG. 3(A)  shows a side cross sectional view of the further other embodiment of the ink cartridge according to the present invention. As shown in  FIG. 3(A) , a side wall  1010  and a side wall  1030 , which extend to the vertical direction to the ink surface, faces each other. The wave preventing wall  1192   c  extends from the side wall  1010  to the side wall  1030 . 
     FIG. 3(B)  shows a cross sectional view from the front of the ink cartridge of  FIG. 3(A) . A gap is provided between the side wall  1020  and the wave preventing wall  1192   c  so that ink can pass through the gap. 
     FIG. 4  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. In the present embodiment, the actuator  106  is provided on the sloped face formed on the bottom face  1   a . The wave preventing wall  1192   d  extends from the periphery of the ink supply port  2  within the inside wall of the container to face to the actuator  106 . 
     FIG. 5(A)  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. 
   In  FIG. 5  to  FIG. 7 , the actuator  106  is mounted on the side wall  1030  which extends to the vertical direction to the ink surface. Furthermore, the wave preventing wall  1192   e  to  1192   g  extends substantially vertical to the ink surface, that is, parallel with the side wall  1030 . 
   The wave preventing wall  1192   e  is provided on the position where directly faces to the actuator  106 . The wave preventing wall  1192   e  extends from the bottom face  1   a . Furthermore, a gap is provided between the top wall  1040  and the top of wave preventing wall  1192   e.    
     FIG. 5(B)  shows a cross sectional view from the front of the ink cartridge of  FIG. 5(A) . A gap is provided between the side wall  1020  and the wave preventing wall  1192   e  so that ink can pass through the gap. Because of the gap, ink does not remain in the actuator  106  side of the container  1 , which is formed by partitioning the container  1  by the wave preventing wall  1192   e , even if ink is consumed. Therefore, the level of ink surface around the actuator  106  is always equal to the level of the ink surface of the other region of the container  1 . Thus, the actuator  106  does not detect mistakenly the ink consumption status. 
   Furthermore, the length of the wave preventing wall  1192   e  from the bottom face  1   a  can be changed according to the height of the actuator  106  to the level of the ink surface and the probability of the generation of ink wave which is influenced by the viscosity of ink. Furthermore, interval of the gap between the wave preventing wall  1192   e  and the side wall  1020  can be changed according to the position of the actuator  106  on the width direction of the ink cartridge, the magnitude of the vibrating region of the actuator  106 , or the characteristic of ink. 
     FIG. 6(A)  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. the actuator  106  is mounted on the side wall  1030 . A wave preventing wall  1192   f  is mounted on the position where directly faces to the actuator  106 . The wave preventing wall  1192   f  extends from the top wall  1040 . Furthermore, a gap is provided between the bottom face  1   a  and the wave preventing wall  1192   f.    
     FIG. 6(B)  shows a cross sectional view from the front of the ink cartridge of  FIG. 6(A) . The wave preventing wall  1192   f  is coupled to the side wall  1020  liquid tightly so that ink can not pass through between the wave preventing wall  1192   f  and the side wall  1020 . By this configuration, ink remains only in the side of the actuator  106  which is formed by partitioning the container  1  by the wave preventing wall  1192   f , even if ink is consumed. However, when ink surface reaches to the lower end of the wave preventing wall  1192   f , gas enters to the actuator  106  side of the container  1  partitioned by the wave preventing wall  1192   f . By the entering of the gas, ink remained in the actuator  106  side of the container  1  partitioned by the wave preventing wall  1192   f  flows out to the ink supply port  2  side, then the medium exits around the actuator  106  changes from ink to gas. Thereby the actuator  106  can detect that the ink inside the ink cartridge is in status of ink end. According to the present embodiment, lower end  192   a  determines the level of ink surface to be an ink end. Therefore, as far as the actuator  106  is provided on the position upper than the lower end  192   a  to the ink surface, actuator  106  can be located in any position on the wall face  1030 . An airhole, which introduces gas, is provided on the top wall of the ink supply port  2  side of the container  1  partitioned by the wave preventing wall  1192   f.    
     FIG. 7(A)  shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator  106  is mounted on the side wall  1030  which is vertical to the ink surface among the wall of the container  1 . A wave preventing wall  1192   g  is provided on the position where directly faces to the actuator  106 . The wave preventing wall  1192   g  extends from the bottom face  1   a  to the top wall  1040 . 
     FIG. 7(B)  shows a cross sectional view from the front of the ink cartridge of  FIG. 7(A) . A gap is provided between the wave preventing wall  1192   g  and the side wall  1020  so that ink can pass through the gap. By this configuration, ink does not remain in the side of the actuator  106  which is formed by partitioning the container  1  by the wave preventing wall  1192   g , even if ink is consumed. Therefore, the level of ink surface around the actuator  106  is always equal to the level of ink surface of the other region of container  1 . Furthermore, the interval of the gap between the wave preventing wall  1192   g  and the side wall  1020  can be changed according to the position of the actuator  106  on the width direction of the ink cartridge, or the characteristic of ink. 
     FIG. 8  to  FIG. 11  show a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator  106  is mounted on the side wall  1010  where the ink supply port  2  is provided. 
   In  FIG. 8 , the wave preventing wall  1192   i  is provided on the position where directly faces to the actuator  106 . The wave preventing wall  1192   i  extends from the supply port wall  2   a  which is a outside wall of the ink supply port  2  among the inside wall nearby the ink supply port  2  of the ink cartridge. On the other hand, a gap is provided between the top wall  1040  and the wave preventing wall  1192   i.    
   Because the cross section viewed from the front of the ink cartridge of the present invention is similar to  FIG. 5(B) , the figure of which will be omitted for  FIG. 8 . There is a gap between the wave preventing wall  1192   i  and the side wall  1020 . Because of the gap, ink does not remain in the actuator  106  side of the container  1 , which is formed by partitioning the container  1  by the wave preventing wall, even if ink is consumed  1192   i  as the embodiment shown in  FIG. 5 . Therefore, the level of ink surface around the actuator  106  is always equal to the level of the ink surface of the other region of the container  1 . 
   In  FIG. 9 , the wave preventing wall  1192   j  is provided on the position where directly faces to the actuator  106 . The wave preventing wall  1192   j  extends from the top wall  1040 . On the other hand, a gap is provided between the supply port wall  2   a  and the wave preventing wall  1192   j.    
   Because the cross section viewed from the front of the ink cartridge of the present invention is similar to  FIG. 6(B) , the figure of which will be omitted for  FIG. 9 . The wave preventing wall  1192   j  is coupled to the side wall  1020  liquid so that ink can not pass through between the wave preventing wall  1192   j  and the side wall  1020 . Therefore, as the embodiment shown in  FIG. 6 , as far as the actuator  106  is provided on the position upper than the lower end  192   a  to the ink surface, the actuator  106  can be located in any position on the wall face  1030 . 
   In  FIG. 10 , the wave preventing wall  1192   k  is provided on the position where directly faces to the actuator  106 . The wave preventing wall  1192   k  extends from the top wall  1040  to the supply port wall  2   a.    
   Because the cross section viewed from the front of the ink cartridge of the present invention is similar to  FIG. 7(B) , the figure of which will be omitted for  FIG. 10 . A gap is provided between the wave preventing wall  1192   k  and the side wall  1020  as shown in  FIG. 7(B) . Therefore, ink does not remain in the side of the actuator  106  which is formed by partitioning the container  1  by the wave preventing wall  1192   k , even if ink is consumed as same as the embodiment of  FIG. 5 . Therefore, the level of ink surface around the actuator  106  is always equal to the level of ink surface of the other region of container  1 . 
     FIG. 11  to  FIG. 13  show a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator  106  is mounted on the boundary between the bottom face  1   a , which is located below the ink surface, and the side wall  1030 , which extends vertical to the ink surface. 
   In  FIG. 11 , a wave preventing wall  1192   m  is fixed to the container  1  such that one end of a wave preventing wall  1192   m  is connected to the bottom face  1   a , and the other end of which is connected to the side wall  1030 . The wave preventing wall  1192   m  is provided on the container  1  such that the wave preventing wall  1192   m  directly faces to the actuator  106  and slopes to the ink surface. There is a gap between the side wall  1020  and the wave preventing wall  1192   m  among the wall of the container  1  in the present embodiment. Therefore, the level of ink surface around the actuator  106  is always equal to the level of ink surface of the other region of container  1  even if ink is consumed. Furthermore, the shape of the wave preventing wall  1192   m  of the present embodiment is substantially plane shape. 
   Because the ink cartridge according the present embodiment mounting the actuator  106  on the boundary of the wall of the container  1 , the positioning of the actuator  106  on the container  1  during the manufacturing of the ink cartridge becomes easy. Moreover, because the length or the width of the wave preventing wall  1192   m  can be shorten, the quantity of the material used for manufacturing the wave preventing wall  1192   m  is reduced. Furthermore, even in the case of manufacturing the wave preventing wall  1192   m  as a independent material with the container  1 , it is relatively easy to positioning the wave preventing wall  1192   m  on the boundary of the wall of the container  1 . Therefore, the manufacturing of the ink cartridge  180  becomes easy. 
   In  FIG. 12 , the position of mounting the actuator  106  and the wave preventing wall  1192   n  on the container  1  is same as the embodiment of the  FIG. 11 . On the other hand, the shape of the wave preventing wall  1192   n  is a part of the spherical shell in the present embodiment. By shaping the wave preventing wall  1192   n  in a shape of spherical shell, the distance between the actuator  106  and the all the part of the wave preventing wall  1192   n  becomes equal. Thereby the wave preventing wall  1192   n  does not influence the residual vibration detected by the actuator  106 . 
   Furthermore, the wave preventing wall  1192   n  can be formed as a part of the hollow cylindrical shape. 
   In  FIG. 13 , the position of mounting the actuator  106  and the wave preventing wall  1192   p  on the container  1  is same as the embodiment of the  FIG. 11 . On the other hand, the wave preventing wall  1192   p  is formed in an L-shape in the present embodiment. The wave preventing wall  1192   p  is provided on the container  1  such that the wave preventing wall  1192   p  has a same distance with the side wall  1030  and the bottom face  1   a . By shaping the wave preventing wall  1192   n  in a L-shape and reducing the gap between the wave preventing wall  1192   p  and the actuator  106  as long as the capillary force does not arise between the wave preventing wall  1192   p  and the actuator  106 , the waving and bubbling of ink around the actuator  106  can be effectively prevented. 
     FIG. 14  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container  8  is divided by division walls into three ink chambers  9 ,  10  and  11 . Ink supply ports  12 ,  13  and  14  are formed for the respective ink chambers. In a bottom face  8   a  of the respective ink chambers  9 ,  10  and  11 , the respective actuator  15 ,  16  and  17  are mounted on the container  8  so that the actuator can contact with the ink which is housed in each ink chamber via the through hole provided on the container  8 . 
   Each of three different wave preventing walls, not shown in the figure, is provided on the position of each of inside of the ink container  9 ,  10  and  11  such that the each of the wave preventing walls faces to the each of actuators  15 ,  16 , and  17 . 
     FIG. 15  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container  8  is divided by partition walls into three ink chambers  9 ,  10  and  11 . Ink supply ports  12 ,  13  and  14  are formed for the respective ink chambers. In a side wall  1028  which extends vertically to the ink surface of the respective ink chambers  9 ,  10  and  11 , the respective actuators  15 ,  16  and  17  are mounted on the container  8 . Each of the actuators  15 ,  16 , and  17  is mounted on the each of the ink chambers  9 ,  10 ,  11  so that the each of the actuators  15 ,  16 , and  17  can contact with the ink which is housed in each ink chamber via the through hole, not shown in the figure, provided on the container  8 . The actuator  16  is mounted a tone of the partition wall, which is provided between the ink chamber  9  and the ink chamber  10 , and the partition wall, which is provided between the ink chamber  10  and the ink chamber  11 . 
   Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber  9 ,  10 , and  11  such that each of the wave preventing walls faces to the actuators  15 ,  16 , and  17  and extends to the vertical direction to the ink surface. 
     FIG. 16  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container  8  is divided by partition walls into three ink chambers  9 ,  10  and  11 . Ink supply ports  12 ,  13  and  14  are formed for the respective ink chambers. Each of actuators  15 ,  16  and  17  is mounted on the container  8  just nearby the each of the ink supply port  12 ,  13 , and  14 , respectively. Each of the actuators  15 ,  16 , and  17  is mounted on the each of the ink chambers  9 ,  10 ,  11  so that the each of the actuators  15 ,  16 , and  17  can contact with the ink which is housed in each ink chamber via the through hole, not shown in the figure, provided on the container  8 . 
   Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber  9 ,  10 , and  11  such that each of the wave preventing walls faces to the actuators  15 ,  16 , and  17  as shown in  FIG. 8  to  FIG. 11 . 
     FIG. 17  is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container  8  has same constitute element as shown in  FIG. 14  to  FIG. 16 . A sloped face which slopes to the ink surface is provided on the bottom face  8   a . Each of actuators  15 ,  16  and  17  is mounted on the sloped face  1025  of each of the ink chambers  9 ,  10 , and  11 . 
   Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber  9 ,  10 , and  11  as shown in  FIG. 4 . 
   Furthermore, the actuators  15 ,  16 , and  17  can be provided on the boundary of the walls that adjoin each other in the container  8 . In this case, each of the wave preventing walls is provided inside the each of the ink chambers  9 ,  10 , and  11  as shown in  FIG. 11  to  FIG. 13 . 
     FIG. 18  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 1 . A carriage  30  capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit  33 , while the recording head  31  is provided in a lower face of the subtank unit  33 . Moreover, the ink supply needle  32  is provided in an ink cartridge mounting face side of the subtank unit  33 . In the present embodiment, the ink cartridge shown in  FIG. 1  is used. Therefore, the wave preventing wall  1192   a  is mounted on the position which faces to the actuator  106 . However, the ink cartridge shown in  FIG. 2  to  FIG. 17  can be used instead of the ink cartridge shown in  FIG. 1 . Therefore, the wave preventing wall shown in  FIG. 2  top  FIG. 17  can be used for the present embodiment. 
     FIG. 19  is a detailed cross sectional view of a subtank unit  33  as an embodiment of the liquid container according to the present invention. The subtank unit  33  comprises the ink supply needle  32 , the ink chamber  34 , a flexible valve  36  and a filter  37 . In the ink chamber  34 , the ink is housed which is supplied from the ink cartridge via ink supply needle  32 . The flexible valve  36  is so designed that the flexible valve  36  is opened and closed by means of the pressure difference between the ink chamber  34  and the ink supply passage  35 . The subtank unit  33  is so constructed that the ink supply passage  35  is communicated with the recording head  31  so that the ink can be supplied up to the recording head  31 . 
   Furthermore, the actuator  106  can be mounted on the side wall  1050  which extends to vertical direction to the ink surface among the wall of the subtank unit  33 . The actuator  106  is mounted on the side wall  1050  so that the actuator  106  can contacts with ink inside the ink chamber  34  through the through hole  1001   c  which is provided on the side wall  1050 . The wave preventing wall  1192   q  extends from the filter  37  to the upward direction to the ink surface so that the wave preventing wall  1192   q  faces to the actuator  106 . A gap is provided between the top wall  1060 , which locates upward the ink surface, and the wave preventing wall  1192   q.    
   A gap is provided between the actuator  106  and the wave preventing wall  1192   q . If ink is filled in the ink cartridge, ink is filled in the gap between the actuator  106  and the wave preventing wall  1192   q . On the other hand, if the ink inside the ink cartridge is consumed, ink is not held in the gap between the actuator  106  and the wave preventing wall  1192   q . That is, the capillary force, which holds ink, does not works between the actuator  106  and the wave preventing wall  1192   q.    
   The cross section of the subtank unit  33  viewed from the direction of the side wall  1050  is similar to the cross section of the ink cartridge shown in  FIG. 5(B) . A gap is provided between the side wall, not shown in the figure, which adjacent to the side wall  1050  and the wave preventing wall  1192   q . The level of the ink surface around the actuator  106  is always equal to the level of the ink surface of the other region of the container  1 . Therefore, with the consumption of the ink inside the ink chamber  34 , the level of ink surface between the side wall  1050  and the wave preventing wall  1192   q  also decreases. The actuator  106  thereby does not mistakenly detect the ink consumption status. 
   Furthermore, the length of the wave preventing wall  1192   q  from the filter  37  can be changed according to the position of the actuator  106  to the level of the ink surface and the probability of the generation of ink wave which is influenced by the viscosity of ink. Furthermore, interval of the gap between the wave preventing wall  1192   q  and the side wall  1020  can be changed according to the position of the actuator  106  on the subtank unit  33 , the magnitude of the vibrating region of the actuator  106 , or the characteristic of ink. 
   Referring to  FIG. 18 , when the ink supply port  2  of the container  1  is inserted through the ink supply needle  32  of the subtank unit  33 , the valve body  6  recedes against the spring  5 , so that an ink passage is formed and the ink inside the container  1  flows into the ink chamber  34 . At a stage where the ink chamber  34  is filled with ink, a negative pressure is applied to a nozzle opening of the recording head  31  so as to fill the recording head with ink. Thereafter, the recording operation is performed. 
   When the ink is consumed in the recording head  31  by the recording operation, a pressure in the downstream of the flexible valve  36  decreases. Then, the flexible valve  36  is positioned away from a valve body  38  so as to become opened as shown in  FIG. 19 . When the flexible valve  36  is opened, the ink in the ink chamber  34  flows into the recording head  31  through the ink passage  35 . Accompanied by the ink which has flowed into the recording head  31 , the ink in the container  1  flows into the subtank unit  33  via the ink supply needle  32 . 
   Moreover, the actuator  106  and the wave preventing wall are provided at least one of the ink cartridge and the subtank unit. However, the actuator  106  and the wave preventing wall can be provided both of the ink cartridge and the subtank unit. 
   By providing the actuator  106  and the wave preventing wall on both of the ink cartridge and the subtank unit, the ink end status of the ink cartridge and the subtank unit can be accurately detected. For example, the recording apparatus can be set to stop the recording operation when one of the cases arises such that the number of the droplets discharged from the recording head reach to the predetermined number of droplets during the measuring of the number of droplets after the actuator  106 , which is mounted on the ink cartridge, detects the ink end or that the actuator  106  mounted on the subtank unit  33  detects the ink end. 
   Furthermore, the recording apparatus can be set to stop the recording operation when both of the cases arises such that the number of the droplets discharged from the recording head reach to the predetermined number of droplets after the actuator  106 , which is mounted on the ink cartridge, detects the ink end and that the actuator  106  mounted on the subtank unit  33  detects the ink end. 
   While the recording apparatus is operating, a drive signal is supplied to the actuator  106  at a period which is set in advance. 
     FIG. 20  is a cross sectional view of another embodiment of a subtank unit  33  of the liquid container according to the present invention. The actuator  106  is mounted on the side wall  1050 . The wave preventing wall  1192   r  extends from the top wall  1060 , which is located upside of the ink surface, downward to the ink surface. There is a gap between the lower end  192   a  of the wave preventing wall  1192   r  and the filter  37 . Moreover, a gap is provided between the wave preventing wall  1192   r  and the side wall adjacent to the side wall  1050 . No capillary force, which holds ink, arises between the wave preventing wall  1192   r  and the actuator  106  as similar to the embodiment shown in  FIG. 19 . 
   Because a gap is provided between the wave preventing wall  1192   r  and the side wall adjacent to the side wall  1050 , the level of the ink surface around the actuator  106  is always equal to the level of the ink surface of the other region of the container  34 . Therefore, the actuator  106  detects the ink end status by detecting the ink surface at the mounting position of the actuator  106 . 
     FIG. 21  is a cross sectional view of further another embodiment of a subtank unit  33  of the liquid container according to the present invention. The actuator  106  is mounted on the side wall  1050 . The wave preventing wall  1192   s  extends from the top wall  1060  until the filter  37 . No capillary force, which holds ink, arises between the wave preventing wall  1192   s  and the actuator  106  as similar to the embodiment shown in  FIG. 19 . 
   Furthermore, a gap is provided between the wave preventing wall  1192   s  and the side wall adjacent to the side wall  1050 . Therefore, the level of the ink surface around the actuator  106  is always equal to the level of the ink surface of the other region of the container  34 . 
     FIG. 22  and  FIG. 23  shows a detail and equivalent circuit of an actuator  106 , which is an embodiment of the piezoelectric device of the present invention. The actuator explained herein is used at least for the method which detects the liquid consumption status in the liquid container by detecting a change in acoustic impedance. Especially, the actuator is used for the method which detects the liquid consumption status in the liquid container by detecting at least the change in acoustic impedance by detecting the resonant frequency from residual vibration.  FIG. 22(A)  is an enlarged plan view of the actuator  106 .  FIG. 22(B)  shows a B-B cross-section of the actuator  106 .  FIG. 22(C)  shows a C-C cross-section of the actuator  106 .  FIG. 23(A)  and  FIG. 23(B)  shows an equivalent circuit of the actuator  106 . Each of  FIG. 23(C)  and  FIG. 23(D)  shows the actuator  106  and around the actuator  106 , and the equivalent circuit of the actuator  106  when an ink is filled in the ink cartridge.  FIG. 23(E)  and  FIG. 23(F)  shows the actuator  106  and around the actuator  106 , and the equivalent circuit of the actuator  106  when there is no ink in the ink cartridge. 
   The actuator  106  includes abase plate  178 , a vibrating plate  176 , a piezoelectric layer  160 , an upper electrode  164  and a lower electrode  166 , an upper electrode terminal  168 , a lower electrode terminal  170 , and a supplementary electrode  172 . The base plate  178  has a circular shape opening  161  on approximately its center. The vibrating plate  176  is provided on one of the face, which is called as “right side” in following, of the base plate  178  such as to cover the opening  161 . The piezoelectric layer  160  is disposed on right side of the surface of the vibrating plate  176 . The upper electrode  164  and the lower electrode  166  sandwich the piezoelectric layer  160  from both sides. The upper electrode terminal  168  connects to the upper electrode  164  electrically. The lower electrode terminal  170  connects to the lower electrode  166  electrically. The supplementary electrode  172  is disposed between the upper electrode  164  and the upper electrode terminal  168  and connects both of the upper electrode  164  and the upper electrode terminal  168 . Each of the piezoelectric layer  160 , upper electrode  164 , and the lower electrode  166  has a circular portion as its main portion. Each of the circular portion of the piezoelectric layer  160 , the upper electrode  164 , and the lower electrode  166  form a piezoelectric element. 
   The vibrating plate  176  is formed on the right side of the surface of the base plate  178  to cover the opening  161 . The cavity  162  is formed by the portion of the vibrating plate  176 , which faces the opening  161 , and the opening  161  of the on the surface of the base plate  178 . The face of the base plate  178  which is opposite side of the piezoelectric element, called as “back side” in following, is faced with the liquid container side. The cavity  162  is constructed such that the cavity  162  contacts with liquid. The vibrating plate  176  is mounted on the base plate  178  such that the liquid does not leak to the right side of the surface of the base plate  178  even if the liquid enters inside the cavity  162 . 
   The lower electrode  166  is located on the right side of the vibrating plate  176 , that is, opposite side against the liquid container. The lower electrode  166  is provided on the vibrating plate  176  such that the center of the circular portion of the lower electrode  166 , which is a main portion of the lower electrode  166 , and the center of the opening  161  substantially matches. The area of the circular portion of the lower electrode  166  is set to be smaller than the area of the opening  161 . The piezoelectric layer  160  is formed on the right side of the surface of the lower electrode  166  such that the center of the circular portion and the center of the opening  161  substantially match. The area of the circular portion of the piezoelectric layer  160  is set to be smaller than the area of the opening  161  and larger than the area of the circular portion of the lower electrode  166 . 
   The upper electrode  164  is formed on the right side of the surface of the piezoelectric layer  160  such that the center of the circular portion, which is a piezoelectric layer  160 , and the center of the opening  161  substantially match. The area of the circular portion of the upper electrode  164  is set to be smaller than the area of the circular portion of the opening  161  and the piezoelectric layer  160  and larger than the area of the circular portion of the lower electrode  166 . 
   Therefore, the main portion of the piezoelectric layer  160  has a structure to be sandwiched by the main portion of the upper electrode  164  and the main portion of the lower electrode each from right side face and back side face, and thus the main portion of the piezoelectric layer  160  can effectively drive and deform the piezoelectric layer  160 . The circular portion, which is a main portion of each of the piezoelectric layer  160 , the upper electrode  164 , and the lower electrode  166 , forms the piezoelectric element in the actuator  106 . As explained above, the electric element contacts with the vibrating plate. Within the circular portion of the upper electrode  164 , circular portion of the piezoelectric layer  160 , the circular portion of the lower electrode, and the opening  161 , the opening  161  has the largest area. By this structure, the vibrating region which actually vibrates within the vibrating plate is determined by the opening  161 . Furthermore, each of the circular portion of the upper electrode  164  and the circular portion of the piezoelectric layer  160  and the circular portion of the lower electrode has smaller area than the area of the opening  161 . The vibrating plate becomes easily vibrate. Within the circular portion of the lower electrode  166  and the circular portion of the upper electrode  164  which connects to the piezoelectric layer  160  electrically, the circular portion of the lower electrode  166  is smaller than the circular portion of the upper electrode  164 . Therefore, the circular portion of the lower electrode  166  determines the portion which generates the piezoelectric effect within the piezoelectric layer  160 . 
   The center of the circular portion of the piezoelectric layer  160 , the upper electrode  164 , and the lower electrode  166 , which form the piezoelectric element, substantially match to the center of the opening  161 . Moreover, the center of the circular shape opening  161 , which determines the vibrating section of the vibrating plate  176 , is provided on the approximately center of the actuator  106 . Therefore, the center of the vibrating section of the actuator  106  matches to the center of the actuator  106 . Because the main portion of the piezoelectric element and the vibrating section of the vibrating plate  176  have a circular shape, the vibrating section of the actuator  106  is symmetrical about a center of the actuator  106 . 
   Because the vibrating section is symmetrical about a center of the actuator  106 , the excitation of the unnecessary vibration occurred owing to the asymmetric structure can be prevented. Therefore, the accuracy of detecting the resonant frequency increases. Furthermore, because the vibrating section is symmetric about the center of the actuator  106 , the actuator  106  is easy to manufacture, and thus the unevenness of the shape for each of the piezoelectric element can be decreased. Therefore, the unevenness of the resonant frequency for each of the piezoelectric element  174  decreases. Furthermore, because the vibrating section has an isotropic shape, the vibrating section is difficult to be influenced by the unevenness of the fixing during the bonding process. That is, the vibrating section is bonded to the liquid container uniformly. Therefore, the actuator  106  is easy to assemble to the liquid container. 
   Furthermore, because the vibrating section of the vibrating plate  176  has a circular shape, the lower resonant mode, for example, the primary resonant mode dominates on the resonant mode of the residual vibration of the piezoelectric layer  160 , and thus the single peak appears on the resonant mode. Therefore, the peak and the noise can be distinguished clearly so that the resonant frequency can be clearly detected. Furthermore, the accuracy of the detection of the resonant frequency can be further increased by enlarge the area of the vibrating section of the circular shape vibrating plate  176  because the difference of the amplitude of the counter electromotive force and the difference of the amplitude of the resonant frequency occurred by whether the liquid exists inside the liquid container increase. 
   The displacement generated by the vibration of the vibrating plate  176  is larger than the displacement generated by the vibration of the base plate  178 . The actuator  106  has a two layers structure that is constituted by the base plate  178  having a small compliance which means it is difficult to be displaced by the vibration, and the vibrating plate  176  having a large compliance which means it is easy to be displaced by the vibration. By this two layers structure, the actuator  106  can be reliably fixed to the liquid container by the base plate  178  and at the same time the displacement of the vibrating plate  176  by the vibration can be increased. Therefore, the difference of the amplitude of the counter electromotive force and the difference of the amplitude of the resonant frequency depended on whether the liquid exists inside the liquid container increases, and thus the accuracy of the detection of the resonant frequency increases. Furthermore, because the compliance of the vibrating plate  176  is large, the attenuation of the vibration decreases so that the accuracy of the detection of the resonant frequency increases. The node of the vibration of the actuator  106  locates on the periphery of the cavity  162 , that is, around the margin of the opening  161 . 
   The upper electrode terminal  168  is formed on the right side of the surface of the vibrating plate  176  to be electrically connected to the upper electrode  164  through the supplementary electrode  172 . The lower electrode terminal  170  is formed on the right side of the surface of the vibrating plate  176  to be electrically connected to the lower electrode  166 . Because the upper electrode  164  is formed on the right side of the piezoelectric layer  160 , there is a difference in depth that is equal to the sum of the thickness of the piezoelectric layer  160  and the thickness of the lower electrode  166  between the upper electrode  164  and the upper electrode terminal  168 . It is difficult to fill this difference in depth only by the upper electrode  164 , and even it is possible to fill the difference in depth by the upper electrode  164 , the connection between the upper electrode  164  and the upper electrode terminal  168  becomes weak so that the upper electrode  164  will be cut off. Therefore, this embodiment uses the supplementary electrode  172  as a supporting member to connects the upper electrode  164  and the upper electrode terminal  168 . By this supplementary electrode  172 , both of the piezoelectric layer  160  and the upper electrode  164  are supported by the supplementary electrode  172 , and thus the upper electrode  164  can have desired mechanical strength, and also the upper electrode  164  and the upper electrode terminal  168  can be firmly connected. 
   The piezoelectric element and the vibrating section which faces to the piezoelectric element within the vibrating plate  176  constitute the vibrating section which actually vibrates in the actuator  106 . Moreover, it is preferable to form the actuator  106  in one body by firing together the member included in the actuator  106 . By forming the actuator  106  as one body, the actuator  106  becomes easy to be handled. Further, the vibration characteristic increases by increasing the strength of the base plate  178 . That is, by increasing the strength of the base plate  178 , only the vibrating section of the actuator  106 , vibrates, and the portion other than the vibrating section of the actuator  106  does not vibrates. Furthermore, the prevention of the vibration of the portion other than the vibrating section of the actuator  106  can be achieved by increasing the strength of the base plate  178  and at the same time forming the actuator  106  as thinner and smaller as possible and forming the vibrating plate  176  as thinner as possible. 
   It is preferable to use lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), or piezoelectric membrane without using lead as a material for the piezoelectric layer  160 . It is preferable to use zirconia or alumina as a material of the base plate  178 . Furthermore, it is preferable to use same material as base plate  178  for a material of vibrating plate  176 . The metal such as gold, silver, copper, platina, aluminum, and nickel having a electrical conductivity can be used for the material of the upper electrode  164 , the lower electrode  166 , the upper electrode terminal  168 , and the lower electrode terminal  170 . 
   The actuator  106  constructed as explained above can be applied to the container which contains liquid. For example, the actuator  106  can be mounted on an ink cartridge used for the ink jet recording apparatus, an ink tank, or a container which contains washing liquid to wash the recording head. 
   The actuator  106  shown in the  FIG. 22  and  FIG. 23  is mounted on the predetermined position on the liquid container so that the cavity  162  can contact with the liquid contained inside the liquid container. When the liquid container is filled with liquid sufficiently, the inside and outside of the cavity  162  is filled with liquid. On the other hand, if the liquid inside liquid container consumed and the liquid level decreased under the mounting position of the actuator, there are conditions that liquid does not exit inside the cavity  162  or that liquid is remained only in the cavity  162  and air exits on outside the cavity  162 . The actuator  106  detects at least the difference in the acoustic impedance occurred by this change in condition. By this detection of the difference in acoustic impedance, the actuator  106  can detects the whether the liquid is sufficiently filled in the liquid container or liquid is consumed more than predetermined level. Furthermore, the actuator  106  can detects the type of the liquid inside the liquid container. 
   The principle of the detection of the liquid level by the actuator will be explained. 
   To detect the acoustic impedance of a medium, an impedance characteristic or an admittance characteristic is measured. To measure the impedance characteristic or the admittance characteristic, for example, transmission circuit can be used. The transmission circuit applies a constant voltage on the medium and measure a current flow through the medium with changing a frequency. The transmission circuit provides a constant current to the medium and measures a voltage applied on the medium with changing a frequency. The change in current value and the voltage value measured at the transmission circuit shows the change in acoustic impedance. Furthermore, the change in a frequency fm, which is a frequency when the current value or the voltage value becomes maximum or minimum, also shows the change in acoustic impedance. 
   Other than method shown above, the actuator can detects the change in the acoustic impedance of the liquid using the change only in the resonant frequency. The piezoelectric element, for example, can be used in a case of using the method of detecting the resonant frequency by measuring the counter electromotive force generated by the residual vibration, which is remained in the vibrating section after the vibration of the vibrating section of the actuator, as a method of using the change in the acoustic impedance of the liquid. The piezoelectric element is element which generates the counter electromotive force by residual vibration remained in the vibrating section of the actuator. The magnitude of the counter electromotive force changes with the amplitude of the vibrating section of the actuator. Therefore, the larger the amplitude of the vibrating section of the actuator, the easier to detect the resonant frequency. Moreover, depends on the frequency of the residual vibration at the vibrating section of the actuator, the period, on which the magnitude of the counter electromotive force changes, changes. Therefore, the frequency of the vibrating section of the actuator corresponds to the frequency of the counter electromotive force. Here, the resonant frequency means the frequency when the vibrating section of the actuator and the medium, which contacts to the vibrating section, are in a resonant condition. 
   To obtain the resonant frequency fs, the waveform obtained by measuring the counter electromotive force when the vibrating section and the medium are in resonant condition is Fourier transformed. Because the vibration of the actuator is not a displacement for only one direction, but the vibration involves the deformation such as deflection and extension, the vibration has various kinds of frequency including the resonant frequency fs. Therefore, the resonant frequency fs is judged by Fourier transforming the waveform of the counter electromotive force when the piezoelectric element and the medium are in the resonant condition and then specifying the most dominating frequency components. 
   The frequency fm is a frequency when the admittance of the medium is maximum or the impedance is minimum. The frequency fm is different from the resonant frequency fs with little value because of the dielectric loss and the mechanical loss. However, the frequency fm is generally used as substitution for resonant frequency because it needs time for deriving the resonant frequency fs from the frequency fm which is actually measured. By inputting output of the actuator  106  to the transmission circuit, the actuator  106  can at least detect the acoustic impedance. 
   It is proved by the experiment that there is almost no differences with the resonant frequency obtained by the method, which measures the frequency fm by measuring the impedance characteristic and admittance characteristic of the medium, and the method, which measures the resonant frequency fs by measuring the counter electromotive force generated by the residual vibration at the vibrating section of the actuator. 
   The vibrating region of the actuator  106  is a portion which constitutes the cavity  162  that is determined by the opening  161  within the vibrating plate  176 . When liquid is sufficiently filled in the liquid container, liquid is filled in the cavity  162 , and the vibrating region contacts with liquid inside the liquid container. When liquid does not exists in the liquid container sufficiently, the vibrating region contacts with the liquid which is remained in the cavity inside the liquid container, or the vibrating region does not contacts with the liquid but contacts with the gas or vacuum. 
   The cavity  162  is provided on the actuator  106  of the present invention, and it can be designed that the liquid inside the liquid container remains in the vibrating region of the actuator  106  by the cavity  162 . The reason will be explained as follows. 
   Depends on the mounting position and mounting angle of the actuator  106  on the liquid container, there is a case in which the liquid attaches to the vibrating region of the actuator even the liquid level in the liquid container is lower than the mounting position of the actuator. When the actuator detects the existence of the liquid only from the existence of the liquid on the vibrating region, the liquid attached to the vibrating region of the actuator prevents the accurate detection of the existence of the liquid. For example, If the liquid level is lower than the mounting position of the actuator, and the drop of the liquid attaches to the vibrating region by the waving of the liquid caused by the shaking of the liquid container caused by the movement of the carriage, the actuator  106  will misjudges that there is enough liquid in the liquid container. In this way, the malfunction can be prevented by using the actuator having cavity. 
   Furthermore, as shown in  FIG. 23(E) , the case when the liquid does not exit in the liquid container and the liquid of the liquid container remains in the cavity,  162  of the actuator  106  is set as the threshold value of the existence of the liquid. That is, if the liquid does not exist around the cavity  162 , and the amount of the liquid in the cavity is smaller than this threshold value, it is judged that there is no ink in the liquid container. If the liquid exist around the cavity  162 , and the amount of the liquid is larger than this threshold value, it is judged that there is ink in the liquid container. For example, when the actuator  106  is mounted on the side wall of the liquid container, it is judged that there is no ink in the liquid container when the liquid level inside the liquid container is lower than the mounting position of the actuator  106 , and it is judged that there is ink inside the liquid container when the liquid level inside the liquid container is higher than the mounting position of the actuator  106 . By setting the threshold value in this way, the actuator  106  can judge that there is no ink in the liquid container even if the ink in the cavity is dried and disappeared. Furthermore, the actuator  106  can judge that there is no ink in the liquid container even if the ink attaches to the cavity again by shaking of the carriage after the ink in the cavity disappears because the amount of the ink attaches to the cavity again does not exceed the threshold value. 
   The operation and the principle of detecting the liquid condition of the liquid container from the resonant frequency of the medium and the vibrating section of the actuator  106  obtained by measuring the counter electromotive force will be explained reference to  FIG. 22  and  FIG. 23 . A voltage is applied on each of the upper electrode  164  and the lower electrode  166  through the upper electrode terminal  168  and the lower electrode terminal  170 . The electric field is generated on the portion of the piezoelectric layer  160  where the piezoelectric layer  160  is sandwiched by the upper electrode  164  and the lower electrode  166 . By this electric field, the piezoelectric layer  160  deforms. By the deformation of the piezoelectric layer  160 , the vibrating region within the vibrating plate  176  deflects and vibrates. For some period after the deformation of the piezoelectric layer  160 , the vibration with deflection remains in the vibrating section of the actuator  106 . 
   The residual vibration is a free oscillation of the vibrating section of the actuator  106  and the medium. Therefore, the resonant condition between the vibrating section and the medium can be easily obtained by applying the voltage of a pulse wave or a rectangular wave on the piezoelectric layer  160 . Because the residual vibration vibrates the vibrating section of the actuator  106 , the residual vibration also deforms the piezoelectric layer  160 . Therefore, the piezoelectric layer  160  generates the counter electromotive force. This counter electromotive force is detected through the upper electrode  164 , the lower electrode  166 , the upper electrode terminal  168 , and the lower electrode terminal  170 . Because the resonant frequency can be specified by this detected counter electromotive force, the liquid consumption status in the liquid container can be detected. 
   Generally, the resonant frequency fs can be expressed as following.
 
 fs= 1/(2*π*( M *Cact) 1/2   (1)
 
where M denotes the sum of an inertance of the vibrating section Mact and an additional inertance M′; Cact denotes a compliance of the vibrating section.
 
     FIG. 22(C)  shows a cross section of the actuator  106  when the ink does not exist in the cavity in the present embodiment.  FIG. 23(A)  and  FIG. 23(B)  shows the equivalent circuit of the vibrating section of the actuator  106  and the cavity  162  when the ink does not exist in the cavity. 
   The Mact is obtained by dividing the product of the thickness of the vibrating section and the density of the vibrating section by the area of the vibrating section. Furthermore, as shown in the  FIG. 23(A) , the Mact can be expressed as following in detail.
 
Mact=Mpzt+Melectrodel+Melectrode2+Mvib  (2)
 
Here, Mpzt is obtained by dividing the product of the thickness of the piezoelectric layer  160  in the vibrating section and the density of the piezoelectric layer  160  by the area of the piezoelectric layer  160 . Melectrode1 is obtained by dividing the product of the thickness of the upper electrode  164  in the vibrating section and the density of the upper electrode  164  by the area of the upper electrode  164 . Melectrode2 is obtained by dividing the product of the thickness of the lower electrode  166  in the vibrating section and the density of the lower electrode  166  by the area of the lower electrode  166 . Mvib is obtained by dividing the product of the thickness of the vibrating plate  176  in the vibrating section and the density of the vibrating plate  176  by the area of the vibrating region of the vibrating plate  176 . However each of the size of the area of the vibrating region of the piezoelectric layer  160 , the upper electrode  164 , the lower electrode  166 , and vibrating plate  176  have a relationship as shown above, the difference among each of the area of the vibrating region is prefer to be microscopic to enable the calculation of the Mact from the thickness, density, and area as whole of the vibrating section. Moreover, it is preferable that the portion other than the circular portion which is a main portion of each of the piezoelectric layer  160 , the upper electrode  164 , and the lower electrode  166  is microscopic so that it can be ignored compared to the main portion. Therefore, Mact is sum of the inertance of the each of the vibrating region of the upper electrode  164 , the lower electrode  166 , the piezoelectric layer  160 , and the vibrating plate  176  in the actuator  106 . Moreover, the compliance Cact is a compliance of the portion formed by the each of the vibrating region of the upper electrode  164 , the lower electrode  166 , the piezoelectric layer  160 , and the vibrating plate  176 .
 
     FIG. 23(A) ,  FIG. 23(B) ,  FIG. 23(D) , and  FIG. 23(F)  show the equivalent circuit of the vibrating section of the actuator  106  and the cavity  162 . In these equivalent circuits, Cact shows a compliance of the vibrating section of the actuator  106 . Each of the Cpzt, Celectrode1, Celectrode2, and Cvib shows the compliance of the vibrating section of the piezoelectric layer  160 , the upper electrode  164 , the lower electrode  166 , and the vibrating plate  176 . Cact can be shown as following equation.
 1/Cact=(1/Cpzt)+(1/Celectrode1)+(1/Celectrode2)+(1/Cvib)  (3) 
   From the equation (2) and (3),  FIG. 23(A)  can be expressed as  FIG. 23(B) . 
   The compliance Cact shows the volume which can accept the medium by the deformation generated by the application of the pressure on the unit area of the vibrating section. In other words, the compliance Cact shows the easiness to be deformed. 
     FIG. 23(C)  shows the cross section of the actuator  106  when the liquid is sufficiently filled in the liquid container, and the periphery of the vibrating region of the actuator  106  is filled with the liquid. The MI max shown in  FIG. 23(C)  shows the maximum value of the additional inertance when the liquid is sufficiently filled in the liquid container, and the periphery of the vibrating region of the actuator  106  is filled with the liquid. The M′max can be expressed as
   M ′max=(π*ρ/(2 *k   3 ))*(2*(2 *k*a ) 3 /(3*π))/(π* a   2 ) 2   (4) 
where a denotes the radius of the vibrating section; ρ denotes the density of the medium; and k denotes the wave number. The equation (4) applies when the vibrating region of the actuator  106  is circular shape having the radius of “a”. The additional inertance M′ shows the quantity that the mass of the vibrating section is increased virtually by the effect of the medium which exists around the vibrating section.
 
   As shown in equation (4), the M′max can changes significantly by the radius of the vibrating section “a” and the density of the medium ρ. 
   The wave number k can be expressed by following equation.
 
 k= 2*π*fact/ c   (5)
 
where fact denotes the resonant frequency of the vibrating section when the liquid does not contact with the vibrating section; and c denotes the speed of the sound propagate through the medium.
 
     FIG. 23(D)  shows an equivalent circuit of the vibrating section of the actuator  106  and the cavity  162  as in the case of  FIG. 23(C)  when the liquid is sufficiently filled in the liquid container, and the periphery of the vibrating region of the actuator  106  is filled with the liquid. 
     FIG. 23(E)  shows the cross section of the actuator  106  when the liquid in the liquid container is consumed, and there is no liquid around the vibrating region of the actuator  106 , and the liquid remains in the cavity  162  of the actuator  106 . The equation (4) shows the maximum inertance M′max determined by such as the ink density ρ when the liquid container is filled with the liquid. On the other hand, if the liquid in the liquid container is consumed and liquid existed around the vibrating section of the actuator  106  becomes gas or vacuum with the liquid remaining in the cavity  162 , the M′ can be expressed as following equation.
   M′=ρ*t/S   (6) 
where t denotes the thickness of the medium related to the vibration; S denotes the area of the vibrating region of the actuator  106 . If this vibrating region is circular shape having a radius of “a”, the S can be shown as S=π*a 2 . Therefore, the additional inertance M′ follows the equation (4) when the liquid is sufficiently filled in the liquid container, and the periphery of the vibrating region of the actuator  106  is filled with the liquid. The additional inertance M′ follows the equation (6) when the liquid in the liquid container is consumed, and there is no liquid exits around the vibrating region of the actuator  106 , and the liquid is remained in the cavity  162 .
 
   Here, as shown in  FIG. 23(E) , let the additional inertance M′, when the liquid in the liquid container is consumed, and there is no liquid exits around the vibrating region of the actuator  106 , and the liquid is remained in the cavity  162 , as M′cav to distinguish with the additional inertance M′max, which is the additional inertance when the periphery of the vibrating region of the actuator  106  is filled with the liquid. 
     FIG. 23(F)  shows an equivalent circuit of the vibrating section of the actuator  106  and the cavity  162  in the case of  FIG. 23(E)  when the liquid in the liquid container is consumed, and there is no liquid around the vibrating region of the actuator  106 , and the liquid remains in the cavity  162  of the actuator  106 . 
   Here, the parameters related to the status of the medium are density of the medium ρ and the thickness of the medium t in equation (6). When the liquid is sufficiently filled in the liquid container, the liquid contacts with the vibrating section of the actuator  106 . When the liquid is insufficiently filled in the liquid container, the liquid is remained in the cavity, or the gas or vacuum contacts with the vibrating section of the actuator  106 . If let the additional inertance during the process of the shifting from the M′max of  FIG. 23(C)  to the M′var of  FIG. 23(E)  when the liquid around the actuator  106  is consumed, because the thickness of the medium t changes according to the containing status of the liquid in the liquid container, the additional inertance M′var changes, and resonant frequency also changes. Therefore, the existence of the liquid in the liquid container can be detected by specify the resonant frequency. Here, if let t=d, as shown in  FIG. 23(E)  and using the equation (6) to express the m′cav, the equation (7) can be obtained by substituting the thickness of the cavity “d” into the “t” in the equation (6).
 
 M ′cav=ρ* d/S   (7)
 
   Moreover, if the medium are different types of liquid with each other, the additional inertance M′ changes and resonant frequency fs also changes because the density ρ is different according to the difference of the composition. Therefore, the types of the liquid can be detected by specifying the resonant frequency fs. Moreover, when only one of the ink or air contacts with the vibrating section of the actuator  106 , and the ink and air is not existing together, the difference in M′ can be detected by calculating the equation (4). 
     FIG. 24(A)  is a graph which shows the relationship between the ink quantity inside the ink tank and the resonant frequency fs of the ink and the vibrating section. Here, the case for the ink will be explained as an example of the liquid. The vertical axis shows the resonant frequency fs, and the horizontal axis shows the ink quantity. When the ink composition is constant, the resonant frequency increases according to the decreasing of the ink quantity. 
   When ink is sufficiently filled in the ink container, and ink is filled around the vibrating region of the actuator  106 , the maximum additional inertance M′max becomes the value shown in the equation (4). When the ink is consumed, and there is no ink around the vibrating region of the actuator  106 , and the ink remains in the cavity  162 , the additional inertance M′var is calculated by the equation (6) based on the thickness of the medium t. Because the “t” used in the equation (6) is the thickness of the medium related to the vibration, the process during which the ink is consumed gradually can be detected by forming the “d” (refer to  FIG. 22(B) ) of the cavity  162  of the actuator  106  as small as possible, that is, forming the thickness of the base plate  178  as sufficiently thinner as possible (refer to  FIG. 23(C) ). Here, let the t-ink as the thickness of the ink involved with the vibration, and t-ink-max as the t-ink when the additional inertance is M′max. For example, the actuator  106  is mounted on the bottom of the ink cartridge horizontally to the surface of the ink. If ink is consumed, and the ink level becomes lower than the height t-ink-max from the actuator  106 , the M′var gradually changes according to the equation (6), and the resonant frequency fs gradually changes according to the equation (1). Therefore, until the ink level is within the range of “t”, the actuator  106  can gradually detect the ink consumption status. 
   Furthermore, by enlarge or lengthen the vibrating section of the actuator  106  and arrange the actuator  106  along a lengthwise direction, the “S” in the equation (6) changes according to the change of ink level with ink consumption. Therefore, the actuator  106  can detect the process while the ink is gradually consumed. For example, the actuator  106  is mounted on the side wall of the ink cartridge perpendicularly to the ink surface. When the ink is consumed and the ink level reaches to the vibrating region of the actuator  106 , because the additional inertance M′ decreases with the decreasing of the ink level, the resonant frequency fs gradually increases according to the equation (1). Therefore, unless the ink level is within the range of the radius  2   a  of the cavity  162  (refer to FIG.  23 (C)), the actuator  106  can gradually detect the ink consumption status. 
   The curve X in  FIG. 24(A)  shows the relationship between the ink quantity contained inside of the ink tank and the resonant frequency fs of the ink and the vibrating section when the vibrating region of the actuator  106  is formed sufficiently large or long. It can be understand that the resonant frequency fs of the ink and vibrating section gradually changes with the decrease of the ink quantity inside the ink tank. 
   In detail, the case when the actuator  106  can detect the process of the gradual consumption of the ink is the case when the liquid and gas having different density with each other are existed together and also involved with vibration. According to the gradual consumption of the ink, the liquid decreases with increasing of the gas in the medium involved with the vibration around the vibrating region of the actuator  106 . For example, the case when the actuator  106  is mounted on the ink cartridge horizontally to the ink surface, and t-ink is smaller than the t-ink-max, the medium involved with the vibration of the actuator  106  includes both of the ink and the gas. Therefore, the following equation (8) can be obtained if let the area of the vibrating region of the actuator  106  as S and express the status when the additional inertance is below M′max in the equation (4) by additional mass of the ink and the gas.
 
 M′=M ′air+ M ′ink=ρair*t-air/ S +ρink*t-ink/ S   (8)
 
where M′max is an inertance of an air; M′ink is an inertance of an ink; ρ air is a density of an air; ρ ink is a density of an ink; t-air is the thickness of the air involved with the vibration; and t-ink is the thickness of the ink involved with the vibration. In case when the actuator  106  is mounted on the ink cartridge approximately horizontally to the ink surface, the t-air increases and the t-ink decreases with the increase of the gas and the decrease of the ink within the medium involved with the vibration around the vibrating region of the actuator  106 . The additional inertance M′ gradually decreases, and the resonant frequency gradually increases by above changes of the t-air and the t-ink. Therefore, the ink quantity remained inside the ink tank or the ink consumption quantity can be detected. The equation (7) depends only on the density of the liquid because of the assumption that the density of the air is small compare to the density of the liquid so that the density of the air can be ignored.
 
   When the actuator  106  is provided on the ink cartridge substantially perpendicular to the ink surface, the status can be expressed as the equivalent circuit, not shown in the figure, on which the region, where the medium involved with the vibration of the actuator  106  is ink only, and the region, where the medium involved with the vibration of the actuator  106  is gas, can be expressed as parallel circuit. If let the area of the region where the medium involved with the vibration of the actuator  106  is ink only as Sink, and let the area of the region where the medium involved with the vibration of the actuator  106  is gas only as Sair, the following equation (9) can be obtained.
 
1 /M′= 1 /M ′air+1 /M ′ink= S air/(ρ air *  t -air)+ S ink/(ρ ink *  t -ink)  (9)
 
   The equation (9) can be applied when the ink is not held in the cavity of the actuator  106 . The case when the ink is held in the cavity can be calculated using the equation (7), (8), and (9). 
   In the case when the thickness of the base plate  178  is thick, that is, the depth of the cavity  162  is deep and d is comparatively close to the thickness of the medium t-ink-max, or in the case when using actuator having a very small vibrating region compared to height of the liquid container, the actuator does not detect the process of the gradual decrease of the ink but actually detects whether the ink level is higher or lower than the mounting position of the actuator. In other words, the actuator detects the existence of the ink at the vibrating region of the actuator. For example, the curve Y in  FIG. 24(A)  shows the relationship between the ink quantity in the ink tank and the resonant frequency fs of the vibrating section when the vibrating section is small circular shape. The curve Y shows that the resonant frequency fs of the ink and the vibrating section changes extremely during the range of change of ink quantity Q, which corresponds to the status before and after the ink level in the ink tank passes the mounting position of the actuator. By this changes of the resonant frequency fs, it can be detected whether the ink quantity remained in the ink tank is more than the predetermined quantity. 
   The method of using the actuator  106  for detecting the existence of the liquid is more accurate than the method which calculates the quantity of ink consumption by the software because the actuator  106  detects the existence of the ink by directly contacting with the liquid. Furthermore, the method using an electrode to detects the existence of the ink by conductivity is influenced by the mounting position to the liquid container and the ink type, but the method using the actuator  106  to detects the existence of the liquid does not influenced by the mounting position to the liquid container and the ink type. Moreover, because both of the oscillation and detection of the existence of the liquid can be done by the single actuator  106 , the number of the sensor mounted on the liquid container can be reduced compare to the method using separate sensor for oscillation and the detection of the existence of the liquid. Therefore, the liquid container can be manufactured at a low price. Furthermore, the sound generated by the actuator  106  during the operation of the actuator  106  can be reduced by setting the vibrating frequency of the piezoelectric layer  160  out of the audio frequency. 
     FIG. 24(B)  shows the relationship between the density of the ink and the resonant frequency fs of the ink and the vibrating section of the curve Y shown in  FIG. 24(A) . Ink is used as an example of liquid. As shown in  FIG. 24(B) , when ink density increases, the resonant frequency fs decreases because the additional inertance increases. In other words, the resonant frequency fs are different with the types of the ink. Therefore, By measuring the resonant frequency fs, it can be confirmed whether the ink of a different density has been mixed together during the re-filling of the ink to the ink tank. 
   Therefore, the actuator  106  can distinguish the ink tank which contains the different type of the ink. 
   The condition when the actuator  106  can accurately detects the status of the liquid will be explained in detail in following. The case is assumed that the size and the shape of the cavity is designed so that the liquid can be remained in the cavity  162  of the actuator  106  even when the liquid inside the liquid container is empty. The actuator  106  can detect the status of the liquid even when the liquid is not filled in the cavity  162  if the actuator  106  can detect the status of the liquid when the liquid is filled in the cavity  162 . 
   The resonant frequency fs is a function of the inertance M. The inertance M is a sum of the inertance of the vibrating section Mact and the additional inertanceM′. Here, the additional inertance M′ has the relationship with the status of the liquid. The additional inertance M′ is a quantity of a virtual increase of a mass of the vibrating section by the effect of the medium existed around the vibrating section. In other words, the additional inertance M′ is the amount of increase of the mass of the vibrating section which is increased by the vibration of the vibrating section that virtually absorbs the medium. 
   Therefore, when the M′cav is larger than the M′max in the equation (4), all the medium which is virtually absorbed is the liquid remained in the cavity  162 . Therefore, the status when the M′cav is larger than the M′max is same with the status that the liquid container is fill with liquid. The resonant frequency fs does not change because the MI does not change in this case. Therefore, the actuator  106  cannot detect the status of the liquid in the liquid container. 
   On the other hand, if the M′cav is smaller than the M′max in the equation (4), the medium which is virtually absorbed is the liquid remained in the cavity  162  and the gas or vacuum in the liquid container. In this case, because the M′ changes, which is different with the case when the liquid is filled in the liquid container, the resonant frequency fs changes. Therefore, the actuator  106  can detect the status of the liquid in the liquid container. 
   The condition whether the actuator  106  can accurately detect the status of the liquid is that the M′cav is smaller than the M′max when the liquid is remained in the cavity  162  of the actuator  106 , and the liquid container is empty. The condition M′max&gt;M′cav, on which the actuator  106  can accurately detect the status of the liquid, does not depend on the shape of the cavity  162 . 
   Here, the M′cav is the mass of the liquid of the volume which is substantially equal to the volume of the cavity  162 . Therefore, the condition, which can detect the status of the liquid accurately, can be expressed as the condition of the volume of the cavity  162  from the inequality M′max&gt;M′cav. For example, if let the radius of the opening  161  of the circular shaped cavity  162  as “a” and the thickness of the cavity  162  as “d”, then the following inequality can be obtained.
 
 M ′max&gt;ρ* d/πa   2   (10)
 
By expanding the inequality (10), the following condition can be obtained.
 
 a/d&gt; 3*π/8  (11)
 
The inequality (10) and (11) are valid only when the shape of the cavity  162  is circular. By using the equation when the M′max is not circular and substituting the area π a 2  with its area, the relationship between the dimension of the cavity such as a width and a length of the cavity and the depth can be derived.
 
   Therefore, if the actuator  106  has the cavity  162  which has the radius of the opening  161  “a” and the depth of the cavity “d” that satisfy the condition shown in inequality (11), the actuator  106  can detect the liquid status without malfunction even when the liquid container is empty and the liquid is remained in the cavity  162 . 
   Because the additional inertance influences the acoustic impedance characteristic, it can be said that the method of measuring the counter electromotive force generated in actuator  106  by residual vibration measures at least the change of the acoustic impedance. 
   Furthermore, according to the present embodiment, the actuator  106  generates the vibration, and the actuator  106  itself measures the counter electromotive force in actuator  106  which is generated by the residual vibration remained after the vibration of the actuator  106 . However, it is not necessary for the vibrating section of the actuator  106  to provide the vibration to the liquid by the vibration of the actuator  106  itself which is generated by the driving voltage. Even the vibrating section itself does not oscillates, the piezoelectric layer  160  deflects and deforms by vibrates together with the liquid, which contacts with the vibrating section with some range. This residual vibration generates the counter electromotive force voltage in the piezoelectric layer  160  and transfer this counter electromotive force voltage to the upper electrode  164  and the lower electrode  166 . The status of the liquid can be detected using this phenomenon. For example, in case of the ink jet recording apparatus, the status of the ink tank or the ink contained inside the ink tank can be detected using the vibration around the vibrating section of the actuator which is generated by the vibration generated by the reciprocating motion of the carriage to scanning the print head during the printing operation. 
     FIG. 25(A)  and  FIG. 25(B)  shows a waveform of the residual vibration of the actuator  106  and the measuring method of the residual vibration. The change of the ink level at the level of the mounting position of the actuator  106  in the ink cartridge can be detected by the change in the frequency or the amplitude of the residual vibration remained after the oscillation of the actuator  106 . In  FIG. 25(A)  and  FIG. 25(B) , the vertical axis shows the voltage of the counter electromotive force generated by the residual vibration of the actuator  106 , and the horizontal axis shows the time. By the residual vibration of the actuator  106 , the waveform of the analog signal of the voltage generates as shown in  FIG. 25(A)  and  FIG. 25(B) . Then, the analog signal is converted to a digital numerical value corresponding to the frequency of the signal. 
   In the example sown in  FIG. 25(A)  and  FIG. 25(B) , the existence of the ink is detected by measuring the time during the generation of the four numbers of pulses from the fourth pulse to the eighth pulse of the analog signal. 
   In detail, after the actuator  106  oscillates, the number of the times when the analog signal get across the predetermined reference voltage form the low voltage side to the high voltage side. The digital signal is set to be high while the analog signal becomes fourth counts to the eighth counts, and the time during fourth counts to the eighth counts is measured by predetermined clock pulse. 
     FIG. 25(A)  shows the waveform when the ink level is above the level of the mounting position of the actuator  106 .  FIG. 25(B)  shows the waveform when the ink level is below the level of the mounting position of the actuator  106 . Comparing the  FIG. 25(A)  and  FIG. 25(B) , the time of the  FIG. 25(A)  during the fourth counts to the eighth counts is longer than the time of the  FIG. 25(B) . In other words, depends on the existence of the ink, the time from the fourth counts to the eighth counts is different. By using this difference of the time, the consumption status of the ink can be detected. The reason to count the analog signal from the fourth counts is to start the measurement of the time after the vibration of the actuator  106  becomes stable. It is only one of the example of starting the measurement from fourth counts, but measurement can be started from the desired counts. 
   The signals from the fourth counts to the eighth counts are detected, and the time from the fourth counts to the eighth counts is measured by the predetermined clock pulse. By this measurement, the resonant frequency can be obtained. The clock pulse is prefer to be a pulse having a same clock with the clock for controlling such as the semiconductor memory device which is mounted on the ink cartridge. It does not necessary to measure the time until the eighth counts, but the time until the desired counts can be measured. In  FIG. 25 , the time from the fourth counts to the eighth counts is measured, however, the time during the different interval of the counts also can be detected according to the circuit configuration which detects the frequency. 
   For example, when the ink quality is stable and the fluctuation of the amplitude of the peak is small, the resonant frequency can be detected by detecting the time from the fourth counts to the sixth counts to increase the speed of detection. Moreover, when the ink quality is unstable and the fluctuation of the amplitude of the pulse is large, the time from the fourth counts to the twelfth counts can be detected to detect the residual vibration accurately. 
   Furthermore, as other embodiments, the wave number of the voltage waveform of the counter electromotive force during the predetermined period can be counted. More specifically, after the actuator  106  oscillates, the digital signal is set to be high during the predetermined period, and the number of the times when the analog signal is get across the predetermined reference voltage from the low voltage side to the high voltage side is counted. By measuring the count number, the existence of the ink can be detected. 
   Furthermore, it can be known by comparing  FIG. 25(A)  with  FIG. 25(B) , the amplitude of the waveform of the counter electromotive force is different when the ink is filled in the ink cartridge and when the ink is not existed in the ink cartridge. Therefore, the ink consumption status in the ink cartridge can be detected by measuring the amplitude of the waveform of the counter electromotive force without calculating the resonant frequency. More specifically, for example, a reference voltage is set between the peak point of the waveform of the counter electromotive force of the  FIG. 25(A)  and the peak point of the waveform of the counter electromotive force of the  FIG. 25(B) . Then, after the actuator  106  oscillates, set the digital signal to be high at the predetermined time. Then, if the waveform of the counter electromotive force get across the reference voltage, it can be judged that there is no ink in the ink cartridge. If the waveform of the counter electromotive force does not get across the reference voltage, it can be judged that there is ink in the ink cartridge. 
     FIG. 26  shows the manufacturing method of the actuator  106 . A plurality of the actuators  106 , four numbers in the case of the  FIG. 26 , are formed as one body. The actuator  106  shown in  FIG. 27  is manufactured by cutting the plurality of actuator  106 , which is formed in one body as shown in  FIG. 26 , at each of the actuator  106 . If the each of the piezoelectric elements of the each of the plurality of the actuator  106 , which is formed in one body as shown in  FIG. 26 , are circular shape, the actuator  106  shown in  FIG. 22  can be manufactured by cutting the actuator  106 , which is formed as one body, at each of actuator  106 . By forming a plurality of the actuator  106  in one body, a plurality of actuator  106  can be manufactured effectively at the same time, and also the handling during the transportation becomes easy. 
   The actuator  106  has a thin plate or a vibrating plate  176 , a base plate  178 , an elastic wave generating device or piezoelectric element  174 , a terminal forming member or an upper electrode terminal  168 , and a terminal forming member or a lower electrode terminal  170 . The piezoelectric element  174  includes a piezoelectric vibrating plate or a piezoelectric layer  160 , an upper electrode  164 , and a lower electrode  166 . The vibrating plate  176  is formed on the top surface of the base plate  178 , and the lower electrode  166  is formed on the top surface of the vibrating plate  176 . The piezoelectric layer  160  is formed on the top surface of the lower electrode  166 , and the upper electrode  164  is formed on the top surface of the piezoelectric layer  160 . Therefore, the main portion of the piezoelectric layer  160  is formed by sandwiching the main portion of the piezoelectric layer  160  by the main portion of the upper electrode  164  and the main portion of the lower electrode  166  from top side and from bottom side. 
   A plurality of the piezoelectric element  174 , four numbers in the case of  FIG. 26 , is formed on the vibrating plate  176 . The lower electrode  166  is formed on the top surface of the vibrating plate  176 . The piezoelectric layer  160  is formed on the top surface of the lower electrode  166 , and the upper electrode  164  is formed on the top surface of the piezoelectric layer  160 . The upper electrode terminal  168  and the lower electrode terminal  170  are formed on the end portion of the upper electrode  164  and the lower electrode  166 . The four numbers of the actuator  106  are used separately by cutting each of the actuator  106  separately. 
     FIG. 27  shows a cross-section of a part of the actuator  106 . The through hole  178   a  is formed on the face of the base plate  178  which faces with the piezoelectric element  174 . The through hole  178   a  is sealed by the vibrating plate  176 . The vibrating plate  176  is formed by the material which has electric insulating characteristic such as alumina and zirconium oxide and also possible to be deformed elastically. The piezoelectric element  174  is formed on the vibrating plate  176  to face with the through hole  178   a . The lower electrode  166  is formed on the surface of the vibrating plate  176  so as to be extended to the one direction, left direction in  FIG. 28 , from the region of the through hole  178   a . The upper electrode  164  is formed on the surface of the piezoelectric layer  160  so as to be extended to the opposite direction of the lower electrode  166 , which is right direction in  FIG. 28 , from the region of the through hole  178   a . Each of the upper electrode terminal  168  and the lower electrode terminal  170  is formed on the surface of the each of supplementary electrode  172  and the lower electrode  166 , respectively. The lower electrode terminal  170  with the lower electrode  166  electrically, and the upper electrode terminal  168  contacts with the upper electrode  164  electrically through the supplementary electrode  172  to deliver a signal between the piezoelectric element and the outside of the actuator  106 . The upper electrode terminal  168  and the lower electrode terminal  170  has a height higher than the height of the piezoelectric element which is the sum of the height of the electrodes and the piezoelectric layer. 
     FIG. 29  shows the manufacturing method of the actuator  106  shown in  FIG. 26 . First, a through hole  940   a  is formed on a green sheet  940  by perforating the green sheet  940  by a press or laser processing. The green sheet  940  becomes the base plate  178  after the burning process. The green sheet  940  is formed by the material such as ceramic material. Then, a green sheet  941  is laminated on the surface of the green sheet  940 . The green sheet  941  becomes the vibrating plate  176  after the burning process. The green sheet  941  is formed by the material such as zirconium oxide. Then, a conductive layer  942 , the piezoelectric layer  160 , and a conductive layer  944  is formed on the surface of the green sheet  941  sequentially by the method such as printing. The conductive layer  942  becomes the lower electrode  166 , and the conductive layer  944  becomes the upper electrode  164  after the burning process. 
   Next, the green sheet  940 , the green sheet  941 , the conductive layer  942 , the piezoelectric layer  160 , and the conductive layer  944  are dried and burned. The spacer member  947  and  948  are provided on the green sheet  941  to raising the height of the upper electrode terminal  168  and the lower electrode terminal  170  to be higher than the piezoelectric element. The spacer member  947  and  948  is formed by printing the same material with the green sheet  940  and  941  or by laminating the green sheet on the green sheet  941 . By this spacer member  947  and  948 , the quantity of the material of the upper electrode terminal  168  and the lower electrode terminal  170 , which is a noble metal, can be reduced. Moreover, because the thickness of the upper electrode terminal  168  and the lower electrode terminal  170  can be reduced, the upper electrode terminal  168  and the lower electrode terminal  170  can be accurately printed to be a stable height. 
   If a connection part  944 ′, which is connected with the conductive layer  944 , and the spacer member  947  and  948  are formed at the same time when the conductive layer  942  is formed, the upper electrode terminal  168  and the lower electrode terminal  170  can be easily formed and firmly fixed. Finally, the upper electrode terminal  168  and the lower electrode terminal  170  are formed on the end region of the conductive layer  942  and the conductive layer  944 . During the forming of the upper electrode terminal  168  and the lower electrode terminal  170 , the upper electrode terminal  168  and the lower electrode terminal  170  are formed to be connected with the piezoelectric layer  160  electrically. 
     FIG. 30  shows the further other embodiment of the ink cartridge of the present invention. In the ink cartridge shown in  FIG. 30 , ink absorbing member  74  is provided in the container  1  to face to the through hole  1   c , which is provided inside the container  1 , as a wave preventing wall. The actuator  70  is fixed to the bottom of the container  1  to face to the through hole  1   c . the ink absorbing member  74  prevents the wave or bubbles of ink inside the ink cartridge to enter into the through hole  1   c . The ink absorbing member thereby prevents the wave or bubbles of ink to move close to the actuator  70  and attach to the actuator  70 . 
   The ink absorbing member  74  is designed such that the hole diameter of the porous part  74   b  around the ink supply port  2  is smaller than the hole diameter of the porous part  74   a  around the actuator  70 . Furthermore, the ink absorbing member  74  is designed such that the capillary force of the porous part  74   b  around the ink supply port  2  is smaller than the capillary force in a degree which holds ink. 
   Thereby, if the ink absorbing member  74  exposes from ink by consuming of ink inside the container  1 , ink in the ink absorbing member  74  flows out from the ink absorbing member  74  by its own weight to the ink supply port  2 . If all the ink inside the container  1  consumed up, the ink absorbing member  74  absorbs the ink remained in the through hole  1   c  by the capillary force. Therefore, ink is drained from the concave part of the through hole  1   c . Therefore, because the residual vibration of the actuator  70  changes at the ink end status, the timing of the ink end can be further reliably detected. 
   Therefore, the ink absorbing member  74  can protect the actuator  70  from the wave of ink and also absorbs the ink remained in the through hole  1   c  to improve the accuracy of the ink end detection of the actuator  106 . 
     FIG. 31  shows further other embodiment of the ink cartridge of the present invention.  FIG. 31(A)  is a cross sectional view of the bottom part of the ink cartridge of the present embodiment. The ink cartridge of the present embodiment has a through hole  1   c  on the bottom face  1   a  of the container  1 , which contains ink. The bottom part of the through hole  1   c  is closed by the actuator  650  and forms an ink storing part. The ink absorbing member  78  is provided around the inside the through hole  1   c  which is provided inside the container  1  and around the through hole  1   c  as a wave preventing wall. The ink absorbing member  78  has a ink absorbing member  78   a  which is provided inside the through hole  1   c  and the ink absorbing member  78   b  which is provided around the through hole  1   c.    
     FIG. 31(B)  shows a detailed cross section of the actuator  650  and the through hole  1   c  shown in  FIG. 31(A) .  FIG. 31(C)  shows a plan view of the actuator  650  and the through hole  1   c  shown in  FIG. 31(B) . The actuator  650  has a vibrating plate  72  and a piezoelectric element  73  which is fixed to the vibrating plate  72 . The vibrating plate  72  can be elastically deformed and is ink resistant. In the present embodiment, the shape of the piezoelectric element  73  and the through hole  1   c  is long and narrow rectangular, and both ends of which is circular shape. 
     FIG. 32  shows other embodiment of the through hole  1   c . In each of  FIGS. 32(A) , (B), and (C), the left hand side of the figure shows the status that there is no ink K in the through hole  1   c , and the right hand side of the figure shows the status that ink K is remained in the through hole  1   c . In the embodiment of  FIG. 31 , the side face of the through hole  1   c  is formed as the vertical wall. In  FIG. 32(A) , the side face  1   d  of the through hole  1   c  is slanted in vertical direction and opens with expanding to the outside. In  FIG. 32(B) , a stepped portion  1   e  and if are formed on the side face of the through hole  1   c . The stepped portion  1   f , which is provided above the stepped portion  1   e , is wider than the stepped portion  1   e . In  FIG. 32(C) , the through hole  1   c  has a groove  1   g  that extends to the direction in which ink is easily discharged, that is, the direction to a ink supply port  2 . 
   A wave preventing wall, not shown in the figure, is provided in the container  1  such that the wave preventing wall faces to the actuator  650 . 
   According to the shape of the through hole  1   c  shown in  FIG. 32(A)  to (C), the quantity of ink K in the ink storing part can be reduced. Therefore, because the M′cav can be smaller than the M′max explained in  FIG. 22  and  FIG. 23 , the vibration characteristic of the actuator  650  at the time of the ink end status can be greatly different with the vibration characteristic when enough quantity of ink K for printing is remained in the container  1 , and thus the ink end status can be reliably detected. 
     FIGS. 33(A)  and (B) is a slant view of the further other embodiment of the actuator.  FIG. 33(B)  shows a part of a side cross section of the ink cartridge, on which an actuator  670  of the embodiment shown in  FIG. 33(A)  is mounted. In the present embodiment, the actuator  670  comprises a concave part forming base plate  80  and a piezoelectric element  82 . The concave part  81  is formed on the one side of the face of the concave part forming base plate  80  by the technique such as etching, and piezoelectric element  82  is mounted on the other side of the face of the concave part forming base plate  80 . The bottom portion of the concave part  81  operates as a vibrating region within the concave part forming base plate  80 . Therefore, the vibrating region of the actuator  670  is determined by the periphery of the concave part  81 . Furthermore, the actuator  670  has the similar structure with the structure of the actuator  106  shown in  FIG. 22 , in which the base plate  178  and the vibrating plate  176  is formed as one body. Therefore, the manufacturing process during the manufacturing an ink cartridge can be reduced, and the cost for manufacturing an ink cartridge also can be reduced. The actuator  670  has a size which can be embedded into the through hole  1   c  provided on the container  1 . By this embedding process, the concave part  81  can operates as the cavity. The actuator  106  shown in  FIG. 22  can be formed to be embedded into through hole  1   c  as actuator  670  shown in  FIG. 33 . Moreover, the wave preventing wall  1192   u  is provided nearby the concave part  81  in the container  1  such that the wave preventing wall  1192   u  faces to the actuator  670 . 
     FIG. 34  shows a slant view of the other embodiment of the actuator. The actuator  660  has packing  76  on the outside of the base plate, which constitutes the actuator  660 , or the through hole  1   c  of a mounting plate  72 . Caulking holes  77  are formed on the outskirts of the actuator  660 . The actuator  660  is fixed to the container  1  through the caulking hole  77  with caulking. 
   Furthermore, also in the present embodiment, the wave preventing wall, not shown in the figure, can be provided nearby the packing  76  such that the wave preventing wall faces to the actuator  670  as shown in  FIG. 33(B) . If the wave preventing wall, not shown in the figure, is form of a mesh or a material which pass through ink such as porous material, the wave preventing wall can be previously mounted on the periphery of the packing  76 . If the wave preventing wall is the member which pass through ink, the actuator  660  can detects ink. In this case, the wave preventing wall  1192   u  is mounted on the ink cartridge together with the actuator  670  as one body. Because the process of mounting the wave preventing wall on the ink cartridge is abbreviate, the manufacturing process is reduced, and the cycle time and cost of manufacturing the ink cartridge are reduced. 
     FIGS. 35A ,  35 B and  35 C show plan views of the through hole  1   c  according to another embodiment. As shown respectively in  FIGS. 35A ,  35 B and  35 C, the plane shape of the through hole  1   c  may be of arbitrary shapes such as circular, rectangular, and triangle shape as long as the elastic wave generating device is capable of being mounted thereto. 
     FIG. 36  shows a slant view of the configuration that forms the actuator  106  in one body as a mounting module  100 . The module  100  is mounted on the predetermined position of the container  1  of an ink cartridge. The module  100  is constituted to detect the ink consumption status in the container  1  by detecting at least the change of acoustic impedance of the ink liquid. The module  100  of the present embodiment has a liquid container mounting member  101  for mounting the actuator  106  to the container  1 . The liquid container mounting member  101  has a structure which mounts a cylindrical part  116  that contains the actuator  106  which oscillates by the driving signal on a base mount  102 , the plan of which is substantially rectangular. Because the module  100  is constructed so that the actuator  106  of the module  100  can not be contact from outside when the module  100  is mounted on the ink cartridge, the actuator  106  can be protected from outside contact. The top side of the edge of the cylindrical part  116  is chamfered so that the cylindrical part  116  can be easily fit into the hole which is formed in the ink cartridge. 
     FIG. 37  shows an exploded view of the module  100  shown in  FIG. 36  to show the structure of the module  100 . The module  100  includes a liquid container mounting member  101  made from a resin and a piezoelectric device mounting member  105  which has a plate  110  and a concave part  113 . Furthermore, the module  100  has a lead wire  104   a  and  104   b , actuator  106 , and a film  108 . Preferably, the plate  110  is made from a material which is difficult to be rust such as stainless or stainless alloy. The opening  114  is formed on the central part of the cylindrical part  116  and the base mount  102  which are included in the liquid container mounting member  101  so that the cylindrical part  116  and the base mount  102  can contain the lead wire  104   a  and  104   b . The concave part  113  is formed on the central part of the cylindrical part  116  and the base mount  102  so that the cylindrical part  116  and the base mount  102  can contain the actuator  106 , the film  108 , and the plate  110 . The actuator  106  is connected to the plate  110  through the film  108 , and the plate  110  and the actuator  106  are fixed to the liquid container mounting member  101 . Therefore, the lead wire  104   a  and  104   b , the actuator  106 , the film  108  and the plate  110  are mounted on the liquid container mounting member  101  as one body. Each of the lead wire  104   a  and  104   b  transfer a driving signal to piezoelectric layer by coupling with the upper electrode and the lower electrode  166  of the actuator  106 , and also transfer the signal of resonant frequency detected by the actuator  106  to recording apparatus. The actuator  106  oscillates temporally based on the driving signal transferred from the lead wire  104   a  and  104   b . The actuator  106  vibrates residually after the oscillation and generates a counter electromotive force by the residual vibration. By detecting the vibrating period of the waveform of the counter electromotive force, the resonant frequency corresponding to the consumption status of the liquid in the liquid container can be detected. The film  108  bonds the actuator  106  and the plate  110  to seal the actuator  106 . The film  108  is preferably formed by such as polyolefin and bonded to the actuator  106  and the plate  110  by heat sealing. By bonding the actuator  106  and the plate  110  with the film  108  face with face, the unevenness of the bonding on location decreases, and thus the portion other than the vibrating plate does not vibrate. Therefore, the change of the resonant frequency before and after bonding the actuator  106  to plate  110  is small. 
   The plate  110  is circular shape, and the opening  114  of the base mount  102  is formed in cylindrical shape. The actuator  106  and the film  108  are formed in rectangular shape. The lead wire  104 , the actuator  106 , the film  108 , and the plate  110  can be attached to and removed from the base mount  102 . Each of the base mount  102 , the lead wire  104 , the actuator  106 , the film  108 , and the plate  110  is arranged symmetric with respect to the central axis of the module  100 . Furthermore, each of the centers of the base mount  102 , the actuator  106 , the film  108 , and the plate  110  is arranged substantially on the central axis of the module  100 . 
   The opening  114  of the base mount  102  is formed such that the area of the opening  114  is larger than the area of the vibrating region of the actuator  106 . The through hole  112  is formed on the center of the plate  110  where the vibrating section of the actuator  106  faces. As shown in  FIG. 22  and  FIG. 23 , the cavity  162  is formed on the actuator  106 , and both of the through hole  112  and the cavity  162  forms ink storing part. The thickness of the plate  110  is preferably smaller than diameter of the through hole  112  to reduce the influence of the residual ink. For example, the depth of the through hole  112  is preferably smaller than one third of the diameter of the through hole  112 . The shape of the through hole  112  is substantially true circle and symmetric with respect to the central axis of the module  100 . Furthermore, the area of the through hole  112  is larger than the area of opening of the cavity  162  of the actuator  106 . The periphery of the shape of the cross-section of the through hole  112  can be tapered shape of stepped shape. The module  100  is mounted on the side, top, or bottom of the container  1  such that the through hole  112  faces to the inside of the container  1 . When the ink is consumed, and the ink around the actuator  106  is exhausted, the resonant frequency of the actuator  106  greatly changes. The change of the ink level can thus be detected. 
     FIG. 38  shows the slant view of the other embodiments of the module. The piezoelectric device mounting member  405  is formed on the liquid container mounting member  101  in the module  400  of the present embodiment. The cylindrical part  403 , which has a cylindrical shape, is formed on the base mount  102 , which has a square shaped plan, the edges of which are rounded, in the liquid container mounting member  401 . Furthermore, the piezoelectric apparatus mounting member  405  includes a board shaped element  405 , which is set up on the cylindrical part  403 , and a concave part  413 . The actuator  106  is arranged on the concave part  413  provided on the side face of the board shaped element  406 . The top end of the board shaped element  406  is chamfered in predetermined angle so that the board shaped element is easy to fit into hole formed on the ink cartridge when mounting the actuator  106  to ink cartridge. 
     FIG. 39  shows an exploded view of the module  400  shown in  FIG. 38  to show the structure of the module  400 . As the module  100  shown in  FIG. 36 , the module  400  includes a liquid container mounting member  401  and a piezoelectric device mounting member  405 . The liquid container mounting member  401  has the base mount  402  and the cylindrical part  403 , and the piezoelectric device mounting member  405  has the board shaped element  406  and the concave part  413 . The actuator  106  is connected to the plate  410  and fixed to the concave part  413 . The module  400  has a lead wire  404   a  and  404   b , actuator  106 , and a film  408 . 
   According to the present embodiment, the plate  410  is rectangular shape, and the opening  414  provided on the board shaped element  406  is formed in rectangular shape. The lead wire  404   a  and  404   b , the actuator  106 , the film  408 , and the plate  410  can be attached to and removed from the base mount  402 . Each of the actuator  106 , the film  408 , and the plate  410  is arranged symmetric with respect to the central axis which is extended to perpendicular direction to the plan of opening  414  and also pass through the center of opening  414 . Furthermore, each of the centers of the actuator  106 , the film  408 , and the plate  410  is arranged substantially on the central axis of the opening  414 . 
   The through hole  412  provided on the center of the plate  410  is formed such that the area of the through hole  412  is larger than the area of the opening of the cavity  162  of the actuator  106 . The cavity  162  of the actuator  106  and the through hole  412  together forms ink storing part. The thickness of the plate  410  is preferably smaller than diameter of the through hole  412 . For example, the thickness of the plate  410  is smaller than one third of the diameter of the through hole  412 . The shape of the through hole  412  is substantially true circle and symmetric with respect to the central axis of the module  400 . The shape of the cross-section of the periphery of the through hole  112  can be tapered shape or stepped shape. The module  400  can be mounted on the bottom of the container  1  such that the through hole  412  is arranged inside of the container  1 . Because the actuator  106  is arranged inside the container  1  such that the actuator  106  extends in the vertical direction, the setting of the timing of the ink end can be easily changed by changing the height of the mounting position of the actuator  106  in the container  1  by changing the height of the base mount  402 . 
     FIG. 40  shows the further other embodiment of the module. As the module  100  shown in  FIG. 36 , the module  500  of  FIG. 40  includes a liquid container mounting member  501  which has a base mount  502  and a cylindrical part  503 . Furthermore, the module  500  further has a lead wire  504   a  and  504   b , actuator  106 , a film  508 , and a plate  510 . The opening  514  is formed on the center of the base mount  502 , which is included in the liquid container mounting member  501 , so that the base mount  502  can contain the lead wire  504   a  and  504   b . The concave part  513  is formed on the cylindrical part  503  so that the cylindrical part  503  can contain the actuator  106 , the film  508 , and the plate  510 . The actuator  106  is fixed to the piezoelectric device mounting member  505  through the plate  510 . Therefore, the lead wire  504   a  and  504   b , the actuator  106 , the film  508 , and the plate  510  are mounted on the liquid container mounting member  501  as one body. The cylindrical part  503 , the top face of which is slanted in vertical direction, is formed on the base mount which has a square shaped plan and the edges of which are rounded. The actuator  106  is arranged on the concave part  513  which is provided on the top surface of the cylindrical part  503  that is slanted in vertical direction. 
   The top end of the module  500  is slanted, and the actuator  106  is mounted on this slanted surface. Therefore, if the module  500  is mounted on the bottom or the side of the container  1 , the actuator  106  slants in the vertical direction of the container  1 . The slanting angle of the top end of the module  500  is substantially between 30 degree and 60 degree with considering the detecting performance. 
   The module  500  is mounted on the bottom or the side of the container  1  so that the actuator  106  can be arranged inside the container  1 . When the module  500  is mounted on the side of the container  1 , the actuator  106  is mounted on the container  1  such that the actuator  106  faces the upside, downside, or side of the container  1  with slanting. When the module  500  is mounted on the bottom of the container  1 , the actuator  106  is preferable to be mounted on the container  1  such that the actuator  106  faces to the ink supply port side of the container  1  with slanting. 
     FIG. 41  shows a cross-sectional view around the bottom of the container  1  when the module  100  shown in  FIG. 36  is mounted on the container  1 . The module  100  is mounted on the container  1  so that the module  100  penetrates through the side wall of the container  1 . The O-ring  365  is provided on the connection face of between the side wall of the container  1  and the module  100  to seal between the module  100  and the container  1 . The module  100  is preferable to include the cylindrical part as explained in  FIG. 36  so that the module  100  can be sealed by the O-ring. By inserting the top end of the module  100  inside the container  1 , ink in the container  1  contacts with the actuator  106  through the through hole  112  of the plate  110 . Because the resonant frequency of the residual vibration of the actuator  106  is different depends on whether the circumference of the vibrating section of the actuator  106  is liquid or gas, the ink consumption status can be detected using the module  100 . Furthermore, not only the module  100  can be mounted on the container  1  and detect the existence of ink, but also the module  400  shown in  FIG. 38 , module  500  shown in  FIG. 40 , or the module  700 A and  700 B shown in  FIG. 42 , and a mold structure  600  can be mounted on the container  1  and detect the existence of the ink. 
     FIG. 42(A)  shows the cross section of the ink container when mounting module  700 B on the container  1 . The present embodiment uses a module  700 B as an example of amounting structure. The module  700 B is mounted on the container  1  such that the liquid container mounting member  360  protrude into the inside of the A through hole  370  is formed in the mounting plate  350 , and the through hole  370  faces to the vibrating section of the actuator  106 . Furthermore, a hole  382  is formed on the bottom wall of the module  700 B, and a piezoelectric device mounting member  363  is formed. The actuator  106  is arranged to close the one of the face of the hole  382 . Therefore, ink contacts with the vibrating plate  176  through the hole  382  of the piezoelectric device mounting member  363  and the through hole  370  of the mounting plate  350 . The hole  382  of the piezoelectric device mounting member  363  and the through hole  370  of the mounting plate  350  together forms an ink storing part. The piezoelectric device mounting member  363  and the actuator  106  are fixed by the mounting plate  350  and the film material. The sealing structure  372  is provided on the connection part of the liquid container mounting member  360  and the container  1 . The sealing structure  372  can be formed by the plastic material such as synthetic resin or O-ring. In  FIG. 42(A) , the module  700 B and the container  1  is separate body, however, the piezoelectric device mounting member can be constituted by a part of the container  1  as shown in  FIG. 42(B) . 
   The module  700 B shown in  FIG. 42  does not need to embed the lead wire into the module as shown in  FIG. 36  to  FIG. 40 . Therefore, the forming process becomes simple. Also, the exchange of the module  700 B becomes possible so that the recycling of the module  700 B also becomes possible. 
   There is possibility that the actuator  106  malfunctions by the contact of the ink which is dropped from a top face or a side face of the container  1  with the actuator  106 , the ink of which is attached to the top face or the side face of the container  1  when the ink cartridge is shaken. However, because the liquid container mounting member  360  of the module  700 B protrudes into the inside of the container  1 , the actuator  106  does not malfunction by the ink dropped from the top face or the side face of the container  1 . 
   Furthermore, the module  700 B is mounted on the container  1  so that only part of the vibrating plate  176  and the mounting plate  350  are contact with ink inside of the container  1  in the embodiment of  FIG. 42(A) . The embedding of the electrode of the lead wire  104   a ,  104   b ,  404   a ,  404   b ,  504   a , and  504  shown in  FIG. 36  to  FIG. 40  into the module becomes unnecessary for the embodiment shown in  FIG. 42(A) . Therefore, the forming process becomes simple. Also, the exchange of the actuator  106  becomes possible so that the recycling of the actuator  106  also becomes possible. 
   FIG.  42 ((B) shows the cross section of the ink container when mounting actuator  106  on the container  1 . A protecting member  361  is mounted on the container separately with the actuator  106  in the ink cartridge of the embodiment shown in FIG.  42 ((B). Therefore, the protecting member  361  and the actuator  106  is not one body as a module, and the protecting member  361  thus can protect the actuator  106  not to be contact by the user. A hole  380  which is provide on the front face of the actuator  106  is arranged on the side wall of the container  1 . The actuator  106  includes the piezoelectric layer  160 , the upper electrode  164 , the lower electrode  166 , the vibrating plate  176 , and the mounting plate  350 . The vibrating plate  176  is formed on the mounting plate  350 , and the lower electrode  166  is formed on the vibrating plate  176 . The piezoelectric layer  160  is formed on the top face of the lower electrode  166 , and the upper electrode  164  is formed on the top face of the piezoelectric layer  160 . 
   Therefore, the main portion of the piezoelectric layer  160  is formed by sandwiching the main portion of the piezoelectric layer  160  by the main portion of the upper electrode  164  and the lower electrode  166  from top and bottom. The circular portion, which is a main portion of each of the piezoelectric layer  160 , the upper electrode  164 , and the lower electrode  166 , forms a piezoelectric element. The piezoelectric element is formed on the vibrating plate  176 . The vibrating region of the piezoelectric element and the vibrating plate  176  constitutes the vibrating section, on which the actuator  106  actuary vibrates. A through hole  370  is provided on the mounting plate  350 . Furthermore, a hole  380  is formed on the side wall of the container  1 . 
   Therefore, ink contacts with the vibrating plate  176  through the hole  380  of the container  1  and the through hole  370  of the mounting plate  350 . The hole  380  of the container land the through hole  370  of the mounting plate  350  together forms ink storing part. 
   Moreover, because the actuator  106  is protected by the protecting member  361 , the actuator  106  can be protected form the outside contact. The base plate  178  shown in  FIG. 22  can be used instead of the mounting plate  350  in the embodiment shown in  FIGS. 42(A)  and (B). 
     FIG. 42(C)  shows an embodiment that comprises a mold structure  600  which includes the actuator  106 . In the present embodiment, a mold structure  600  is used as one example of the mounting structure. The mold structure  600  has the actuator  106  and a mold member  364 . The actuator  106  and the mold member  364  are formed in one body. The mold member  364  is formed by a plastic material such as silicon resin. The mold member  364  includes a lead wire  362  in its inside. The mold member  364  is formed so that the mold member  364  has two legs extended from the actuator  106 . The end of the two legs of the mold member  364  are formed in a shape of hemisphere to liquid tightly fix the mold member  364  with container  1 . The mold member  364  is mounted on the container  1  such that the actuator  106  protrudes into the inside of the container  1 , and the vibrating section of the actuator  106  contacts with ink inside the container  1 . The upper electrode  164 , the piezoelectric layer  160 , and the lower electrode  166  of the actuator  106  are protected from ink by the mold member  364 . 
   Because the mold structure  600  shown in  FIG. 42  does not need the sealing structure  372  between the mold member  364  and the container  1 , the leaking of ink from the container  1  can be reduced. Moreover, because the mold structure  600  has a form that the mold structure  600  does not protrude from the outside of the container  1 , the mold structure  600  can protect the actuator  106  from the outside contact. There is possibility that the actuator  106  malfunctions by the contact of the ink which is dropped from a top face or a side face of the container  1  with the actuator  106 , the ink of which is attached to the top face or the side face of the container  1  when the ink cartridge is shaken. Because the mold member  364  of the mold structure  600  protrudes into the inside of the container  1 , the actuator  106  does not malfunction by the ink dropped from the top face or the side face of the container  1 . 
     FIG. 43  shows an embodiment of an ink cartridge and an ink jet recording apparatus which uses the actuator  106  shown in  FIG. 22 . A plurality of ink cartridges  180  is mounted on the ink jet recording apparatus which has a plurality of ink introducing members  182  and a holder  184  each corresponding to the each of ink cartridge  180 , respectively. Each of the plurality of ink cartridges  180  contains different types of ink, for example, different color of ink. The actuator  106 , which detects at least acoustic impedance, is mounted on the each of bottom of the plurality of ink cartridge  180 . The residual quantity of ink in the ink cartridge  180  can be detected by mounting the actuator  106  on the ink cartridge  180 . 
   Furthermore, the wave preventing wall, not shown in the figure, is provided inside the ink cartridge  180  such that the wave preventing wall faces to the actuator  106 . 
     FIG. 44  shows a detail around the head member of the ink jet recording apparatus. The ink jet recording apparatus has an ink introducing member  182 , a holder  184 , a head plate  186 , and a nozzle plate  188 . A plurality of nozzle  190 , which jet out ink, is formed on the nozzle plate  188 . The ink introducing member  182  has an air supply hole  181  and an ink introducing inlet  183 . The air supply hole  181  supplies air to the ink cartridge  180 . The ink introducing inlet  183  introduces ink from the ink cartridge  180 . The ink cartridge  180  has an air introducing inlet  185  and an ink supply port  187 . The air introducing inlet  185  introduces air from the air supply hole  181  of the ink introducing member  182 . The ink supply port  187  supplies ink to the ink introducing inlet  183  of the ink introducing member  182 . By introducing air from the ink introducing member  182  to the ink cartridge  180 , the ink cartridge  180  accelerates the supply of ink from the ink cartridge  180  to the ink introducing member  182 . 
   Furthermore, the wave preventing wall, not shown in the figure, is provided inside the ink cartridge  180  such that the wave preventing wall faces to the actuator  106 . 
     FIG. 45  shows other embodiment of the ink cartridge  180  shown in  FIG. 44 . The actuator  106  is mounted on the bottom face  194   a , which is formed to be slanted in vertical direction, of the ink cartridge  180 A shown in the  FIG. 45(A) . A wave preventing wall  1192   v  is provided on the position where has the predetermined height from the bottom face of the inside the container  194  and also faces to the actuator  106  inside the container  194  of the ink cartridge  180 . Because the actuator  106  is mounted on the container  194  slanted in vertical direction, the drainage of ink can be improved. 
   A gap, which is filled with ink, is formed between the actuator  106  and the wave preventing wall  1192   v . The gap between the wave preventing wall  1192   v  and the actuator  106  does not hold ink by capillary force. When the container  194  is rolled, ink wave is generated inside the container  194  by the waving, and there is possibility that the actuator  106  malfunctions by detecting gas or an air bubble caused by the shock of the ink wave. By providing the wave preventing wall  1192   v , ink wave around the actuator  106  can be prevented so that the malfunction of the actuator  106  can be prevented. 
   The actuator  106  of the ink cartridge  180 B shown in  FIG. 45(B)  is mounted on the side wall of the supply port of the container  194 . The actuator  106  can be mounted on the side wall or bottom face of the container  194  if the actuator  106  is mounted nearby the ink supply port  187 . The wave preventing wall  1192 W is provided nearby the ink supply port  187  inside the container  194  such that the wave preventing wall  1192 W faces to the actuator  106 . The wave preventing wall  1192   w  is formed in L-shape to effectively prevent the wave of ink. Moreover, the actuator  106  is preferably mounted on the center of the width direction of the container  194 . Because ink is supplied to the outside through the ink supply port  187 , ink and actuator  106  reliably contacts until the timing of the ink near end by providing the actuator  106  nearby the ink supply port  187 . Therefore, the actuator  106  can reliably detect the timing of the ink near end. 
   Furthermore, by providing the actuator  106  nearby the ink supply port  187 , the setting position of the actuator  106  to the connection point on the carriage on the ink container becomes reliable during the mounting of the ink container on the cartridge holder of the carriage. It is because the reliability of coupling between the ink supply port with the ink supply needle is most important during the coupling of the ink container and the carriage. If there is even a small gap, the tip of the ink supply needle will be hurt or a sealing structure such as O-ring will be damaged so that the ink will be leaked. To prevent this kind of problems, the ink jet printer usually has a special structure that can accurately positioning the ink container during the mounting of the ink container on the carriage. Therefore, the positioning of the actuator  106  becomes reliable by arranging the actuator nearby the ink supply port. Furthermore, the actuator  106  can be further reliably positioned by mounting the actuator  106  at the center of the width direction of the container  194 . It is because the waving is the smallest when the ink container rolls along an axis, the center of which is center line of the width direction, during the mounting of the ink container on the holder. 
     FIG. 46  shows further other embodiment of the ink cartridge  180 .  FIG. 46(A)  shows a cross section of an ink cartridge  180 C, and  FIG. 46(B)  shows a cross section which enlarges the side wall  194   b  of an ink cartridge  180 C shown in  FIG. 46(A) .  FIG. 46(C)  shows perspective view from the front of the side wall  194   b  of the ink cartridge  180 C. The semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610  in the ink cartridge  180 C. As shown in  FIG. 46(A)  the wave preventing wall  1192   x  is provided inside the container  194  such that the wave preventing wall  1192   x  faces to the actuator  700 . As shown in  FIG. 46(B)  and (C), the semiconductor memory device  7  is formed on the upper side of the circuit board  610 , and the actuator  106  is formed on the lower side of the semiconductor memory device  7  on the same circuit board  610 . A different-type O-ring  614  is mounted on the side wall  194   b  such that the different-type O-ring  614  surrounds the actuator  106 . A plurality of caulking part  616  is formed on the side wall  194   b  to couple the circuit board  610  with the container  194 . By coupling the circuit board  610  with the container  194  using the caulking part  616  and pushing the different-type O-ring  614  to the circuit board  610 , the vibrating region of the actuator  106  can contacts with ink, and at the same time, the inside of the ink cartridge is sealed from outside of the ink cartridge. 
   A terminals  612  are formed on the semiconductor memory device  7  and around the semiconductor memory device  7 . The terminal  612  transfer the signal between the semiconductor memory device  7  and outside the ink jet recording apparatus. The semiconductor memory device  7  can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610 , the mounting process can be finished at one time during mounting the semiconductor memory device  7  and the actuator  106  on the ink cartridge  180 C. Moreover, the working process during the manufacturing of the ink cartridge  180 C and the recycling of the ink cartridge  180 C can be simplified. Furthermore, the manufacturing cost of the ink cartridge  180 C can be reduced because the numbers of the parts can be reduced. 
   The actuator  106  detects the ink consumption status inside the container  194 . The semiconductor memory device  7  stores the information of ink such as residual quantity of ink detected by the actuator  106 . That is, the semiconductor memory device  7  stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator  106  when detecting the ink consumption status. The semiconductor memory device  7  previously stores the resonant frequency of when ink inside the container  194  is full, that is, when ink is filled in the container  194  sufficiently, or when ink in the container  194  is end, that is, ink in the container  194  is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container  194  is full status or end status can be stored when the ink container is mounted on the ink jet recording apparatus for the first time. Moreover, the resonant frequency when the ink inside the container  194  is full status or end status can be stored during the manufacturing of the container  194 . Because the unevenness of the detection of the residual quantity of ink can be compensated by storing the resonant frequency when the ink inside the container  194  is full status or end status in the semiconductor memory device  7  previously and reading out the data of the resonant frequency at the ink jet recording apparatus side, it can be accurately detected that the residual quantity of ink is decreased to the reference value. 
     FIG. 47  shows further other embodiment of the ink cartridge  180 . The ink cartridge  180 E shown in  FIG. 47(A)  mounts a actuator  606  which is long in vertical direction on the side wall  194   b  of the container  194 . The wave preventing wall  1192   x  is provided inside the container  194  such that the wave preventing wall  1192   x  faces to the whole of the vibrating region of the actuator  106 . The change of the residual quantity of ink inside the container  194  can be detected continuously by the actuator  606  which is long in vertical direction. The length of the actuator  606  is preferably longer than the half of the height of the side wall  194   b . In  FIG. 47(A) , the actuator  606  has the length from the substantially from the top end to the bottom end of the side wall  194   b . Therefore, the wave preventing wall  1192   x  also has a length substantially from the top end to the bottom end of the side wall  194   b . By providing the wave preventing wall  1192   x , the wave preventing wall  1192   x  prevents the wave of ink around the actuator  606  and prevents the malefaction of the actuator  606 . Furthermore, the wave preventing wall  1192   x  prevents the bubble generated by the waving of ink to enter to the actuator  606 . 
   The ink cartridge  180 F shown in  FIG. 47(B)  mounts a plurality of actuators  106  on the side wall  194   b  of the container  194  and comprises a wave preventing wall  1192   x  on the face of the plurality of actuators  606 . The ink cartridge  180 F further comprises the wave preventing wall  1192   x , which is long in vertical direction, along the side wall  194   b  with predetermined gap with the side wall  194   b  inside the container  194 . A gap which is filled with ink is formed between the actuator  106  and the wave preventing wall  1192   x . Moreover, the gap between the wave preventing wall  1192   x  and the actuator  106  has a enough distance such that the gap does not hold ink by capillary force. When the container  194  is rolled, ink wave is generated inside the container  194  by the waving, and there is possibility that the actuator  106  malfunctions by detecting gas or an air bubble caused by the shock of the ink wave. As similar to the embodiment shown in  FIG. 47(B) , by providing the wave preventing wall  1192   x , ink wave around the actuator  106  can be prevented so that the malfunction of the actuator  106  can be prevented. The wave preventing wall  1192   x  also prevents the air bubble generated by the waving of ink to enter to the actuator  106 . 
     FIG. 48  shows further other embodiment of the ink cartridge  180 . The ink cartridge  180 G shown in  FIG. 48(A)  has a top wall  1080  and a bottom wall  1090 , each of which is located on the upside and downside of the ink surface inside the container  194 . A plurality of wave preventing walls  212   a  are extended from the top wall  1080  downward to the bottom wall  1090 . Because each of lower end of the partition walls  212  and the bottom face of the container  194  has a predetermined gap, the bottom part of the container  194  communicates with each other. The ink cartridge  180 G has a plurality of containing chambers  213  divided by the each of plurality of partition walls  212 . The bottom part of the plurality of the containing chambers  213  communicates with each other. The actuator  106  is mounted on the side wall  1070  which faces to the ink supply port  187 . The actuator  106  is arranged on substantially center of the top face  194   c  of the containing chamber  213  of the container  194 . The volume of the containing chamber  213  is arranged such that the volume of the containing chamber  213  of the ink supply port  187  is the largest, and the volume of the containing chamber  213  gradually decreases as the distance from the ink supply port  187  increases to the inner part of the ink cartridge  180 G. Therefore, the containing chamber  213  becomes wider towards from the actuator  106  mounting side of the containing chamber  213  to the ink supply port  187  side of the containing chamber  213 . 
   Because ink is drained from the ink supply port  187 , and air enters from the air introducing inlet  185 , ink is consumed from the containing chamber  213  of the ink supply port  187  side to the containing chamber  213  of the inner part of the ink cartridge  180 G. For example, the ink in the containing chamber  213  which is most near to the ink supply port  187  is consumed, and during the ink level of the containing chamber  213  which is most near to the ink supply port  187  decreases, the other containing chamber  213  are filled with ink. When the ink in the containing chamber  213  which is most near to the ink supply port  187  is consumed totally, air enters to the containing chamber  213  which is second by counted from the ink supply port  187 , then the ink in the second containing chamber  213  is beginning to be consumed so that the ink level of the second containing chamber  213  begin to decrease. At this time, ink is filled in the containing chamber  213  which is third or more than third by counted from the ink supply port  187 . In this way, ink is consumed from the containing chamber  213  which is most near to the ink supply port  187  to the containing chamber  213  which is far from the ink supply port  187  in order. 
   As shown above, because the actuator  106  is arranged on the containing chamber  213  that is farthermost from the ink supply port  187 , the actuator  106  can detect the ink end. Furthermore, the plurality of wave preventing walls  212   a  can effectively prevent the waves of ink. 
   The ink cartridge  180 H shown in  FIG. 48(B)  has a top wall  1080  and a bottom wall  1090 , each of which is located on the upside and downside of the ink surface inside the container  194 . A plurality of wave preventing walls  212   b  are extended from the top wall  1080  and the bottom wall  1090  alternately. There are gap between the partition wall  212   b , which extends from the bottom wall  1090 , among the plurality of the wave preventing wall  212   b  and the side wall, not shown in the figure, located on width direction of the container  194 . Therefore, the level of ink surface in each containing chamber  213  is equal. 
   Furthermore, among the plurality of wave preventing wall  212   b , the wave preventing wall  212   b  which extends from the top wall  1090  and the side wall, not shown in the figure, located on width direction of the container  194  can be coupled liquid-tightly or air-tightly. In case the wave preventing wall  212   b  which is nearest to the actuator  106  among the plurality of wave preventing wall  212   b  extends from the top wall  1080 , gas enters to the containing chamber  213  which is nearest to the actuator  106  when the level of ink surface inside the container  194  reaches to the lower end of the wave preventing wall  212   b  which is nearest to the actuator  106 . Therefore, the level of ink surface for detecting the ink end is determined by the position of the lower end  212   f  to the level of ink surface along a vertical direction 
   In the ink cartridge  180 I shown in  FIG. 48(C) , the actuator  106  is mounted on the side wall  1070  around the boundary of the side wall  1070  and the top wall  1080 . The ink cartridge  180 I includes at least two containing chambers of containing chamber  213   a  and containing chamber  213   b  which are partitioned by the wave preventing wall  212   c . Among two containing chambers, a negative pressure generating member  1100  which generates a negative pressure is provided on the supply port side containing chamber  213   a  which is relatively near to the ink supply port  187 . Among two containing chambers, the actuator  106  is provided on the inner side containing chamber  213   b  which is relatively far from the ink supply port  187 . 
   A buffer  214  is formed on the top wall  1080  of the containing chamber  213   b . The buffer  214  is a concave part which accepts the bubble which enters into the ink cartridge  180 I when the ink cartridge  180 I is manufactured or when the ink cartridge  180 I is left for a long period without to be used. In  FIG. 48(C) , the buffer  214  is formed as a concave part which overhangs from the side wall  194   b  of the container  194 . Because the negative pressure generating member  1100  and the buffer  214  accepts the bubbles enters inside the containing chamber  213   b , the negative pressure generating member  1100  and the buffer  214  can prevent the malfunction of the actuator  106  such as detecting the ink end by the attaching of bubbles on the actuator  106 . Furthermore, the ink quantity which can be consumed after detecting the ink end can be changed by changing the capacity of containing chamber  213   b  and the length of the wave preventing wall  212   c.    
   In the ink cartridge  180 J shown in  FIG. 48(D) , a plurality of wave preventing walls  212   d  are extended from the side wall  1070  and the side wall  1110  of the container  194  alternately. Furthermore, each of one end  212   dd  of each of the wave preventing wall  212   d  is sloped toward the upside of ink surface. Moreover, A gap, in a degree which can pass through ink, is provided between the each of wave preventing walls  212   d  and the side wall, not shown in the figure, which intervene between the side wall  1070  of the container  194  and the side wall  1110 . Therefore, ink does not remain on the wave preventing wall  212   d . A plurality of actuators  106  are mounted on the side wall  1070  which extends substantially vertically to ink surface among the wall of container  194 . A plurality of actuators  106  is mounted on the different height to the ink surface with each other. Thereby the actuator  106  can detect the ink consumption status step by step. In the present embodiment, the buffer  214  is provided around the side wall  1070  of the actuator  106  mounting side among the top wall  1080 . 
     FIG. 49  shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. In the ink cartridge  180 K of the present embodiment, the actuator  106  is mounted on the side wall  1070  which faces to the ink supply port  187 . Each of a plurality of wave preventing wall  212   e  extends from the first side wall  1120   a  and the second side wall  1120   b , which intervene between side wall  1070  and the side face where the ink supply port  187  is provided, alternatively. By the plurality of wave preventing wall  212   e  which extends from the side wall  1120   a  and the  1120   b , the actuator  106  is effectively protected from the wave of ink and the generation of the bubbles is suppressed. 
     FIG. 50  shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. In the ink cartridge  180 L of the present embodiment, the actuator  106  is mounted on the side wall  1070  which faces to the ink supply port  187 . The wave preventing wall  212   g  includes a bending part  800 , at least a part of the end of the wave preventing wall of which is bent toward the side wall  1070  where the actuator  106  is mounted. A capillary force does not work between the wave preventing wall  212   g  and the actuator  106 . Furthermore, a gap, on which a capillary force works, is provided between the bending part  800  and the side wall  1070 . Therefore, the entering of the bubbles between the actuator  106  and the wave preventing wall  212   g  can be prevented. The ink level around the actuator  106  is equal to the other ink level in the ink cartridge  180 L. Therefore, the actuator  106  can accurately detect the ink consumption status inside the ink cartridge  180 L. 
     FIG. 51  shows other embodiment of the ink cartridge using the actuator  106 . The ink cartridge  220 A shown in  FIG. 51(A)  has a first wave preventing wall  222  provided such that it extends from the top wall  1081 , which locates upside of the ink surface, downward to the ink surface among the wall of the ink cartridge  220 A. Because there is a predetermined gap between the lower end of the first wave preventing wall  222  and the bottom wall  1091  of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the bottom face of the ink cartridge  220 A. A second wave preventing wall  224  is formed such that the second wave preventing wall  224  extends upward from the bottom face of the ink cartridge  220 A on the ink supply port  230  side of the first wave preventing wall  222 . Because there is a predetermined gap between the upper end of the second wave preventing wall  224  and the top face of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the top face of the ink cartridge  220 A. 
   A ventilation side ink chamber  225   a  is formed on the inner part of the first wave preventing wall  222 , seen from the ink supply port  230 , by the first wave preventing wall  222 . On the other hand, a detection side ink chamber  225   b  is formed on the front side of the second wave preventing wall  224 , seen from the ink supply port  230 , by the second wave preventing wall  224 . The volume of the ventilation side ink chamber  225   a  is larger than the volume of the detection side ink chamber  225   b . A detection side small ink chamber  227  is formed by providing a gap, which can generate the capillary phenomenon, between the first wave preventing wall  222  and the second wave preventing wall  224 . Therefore, the ink in the ventilation side ink chamber  225   a  is collected to the detection side small ink chamber  227  by the capillary force of the detection side small ink chamber  227 . Therefore, the detection side small ink chamber  227  can prevent that the air or air bubble enters into the detection side ink chamber  225   b . Furthermore, the ink level in the detection side ink chamber  225   b  can decrease steadily and gradually. Because the ventilation side ink chamber  225   a  is formed at more inner part of the detection side ink chamber  225   b , seen from the ink supply port  230 , the ink in the detection side ink chamber  225   b  is consumed after the ink in the ventilation side ink chamber  225   a  is consumed. 
   The actuator  106  is mounted on the side wall  1071  of the ink cartridge  220 A of the ink supply port  230  side, that is, the side wall  1071  of the detection side ink chamber  225   b  of the ink supply port  230  side. The actuator  106  detects the ink consumption status inside the detection side ink chamber  225   b . The residual quantity of ink at the timing closed to the ink near end can be detected stably by mounting the actuator  106  on the side wall  1071  of the detection side ink chamber  225   b . Furthermore, by changing the height of the mounting position of the actuator  106  on the side wall  1071  of the detection side ink chamber  225   b , the timing to determine which ink residual quantity as an ink end can be freely set. Because ink is sullied from the ventilation side ink chamber  225   a  to the detection side ink chamber  225   b  by the detection side small ink chamber  227 , the actuator  106  does not influenced by the waving of ink caused by the waving of the ink cartridge  220 A, and actuator  106  can thus reliably measure the ink residual quantity. Furthermore, because the detection side small ink chamber  227  holds ink, the detection side small ink chamber  227  can prevent ink to flow backward from the detection side ink chamber  225   b  to the ventilation side ink chamber  225   a.    
   A check valve  228  is provided on the top face of the ink cartridge  220 A. The leaking of ink outside of the ink cartridge  220 A caused by the waving of the ink cartridge  220 A can be prevented by the check valve  228 . Furthermore, the evaporation of ink from the ink cartridge  220 A can be prevented by providing the check valve  228  on the top face of the ink cartridge  220 A. If ink in the ink cartridge  220 A is consumed, and negative pressure inside the ink cartridge  220 A exceeds the pressure of the check valve  228 , the check valve  228  opens and introduces air into the ink cartridge  220 A. Then the check valve  228  closes to maintain the pressure inside the ink cartridge  220 A to be stable. 
     FIGS. 51(C)  and (D) shows a detailed cross-section of the check valve  228 . The check valve  228  shown in  FIG. 51(C)  has a valve  232  which includes flange  232   a  formed by rubber. An airhole  233 , which communicates air between inside and outside of the ink cartridge  220 , is provided on the ink cartridge  220  such that the airhole  233  faces to the flange  232   a . The airhole  233  is opened and closed by the flange  232   a . The check valve  228  opens the flange  232   a  inward the ink cartridge  220  when the negative pressure in the ink cartridge  220  exceeds the pressure of the check valve  228  by the decrease of ink inside the ink cartridge  220 A, and thus the air outside the ink cartridge  220  is introduced into the ink cartridge  220 . The check valve  228  shown in  FIG. 51(D)  has a valve  232  formed by rubber and a spring  235 . If the negative pressure inside the ink cartridge  220  exceeds the pressure of the check valve  228 , the valve  232  presses and opens the spring  235  to introduce the outside air into the ink cartridge  220  and then closes to maintain the negative pressure inside the ink cartridge  220  to be stable. 
   The ink cartridge  220 B shown in FIG.  51 ((B) has a porous member  242  in the ventilation side ink chamber  225   a  instead of providing the check valve  228  on the ink cartridge  220 A as shown in  FIG. 51(A) . The porous member  242  holds the ink inside the ink cartridge  220 B and also prevents ink to be leaked outside of the ink cartridge  220 B during the waving of the ink cartridge  220 B. 
     FIG. 52  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink as an embodiment of the liquid container according to the present invention. An ink cartridge shown in  FIG. 52  is based on the method that detects the position of the liquid surface or an existence of liquid inside a liquid container by detecting a resonant frequency by measuring the counter electromotive force generated by the residual vibration remained in the vibrating section among the above mentioned method. The actuator  106  is used for an embodiment of the liquid censor that detects liquid. The ink cartridge of the embodiment shown in  FIG. 52  comprises a container  1  which contains liquid K and includes top wall  1030  located upside of the liquid surface of ink K, an ink supply port  2  which supplies liquid K outside the container  1 , an actuator  106  which detects ink consumption status inside the container  1 , and a first partition wall  193   a  which partitions at least two ink chamber such that ink K in both of the ink chamber can communicate with each other inside the container  1 . At least two ink chambers include a ventilation side ink chamber  123   a  which communicate with atmosphere and the detecting side ink chamber  123   b . The actuator  106  is mounted on the top wall  1030  of the ink chamber  123   b.    
   The airhole  233  is provided on the top wall  1030  of the ventilation side ink chamber  123   a  which ventilates with atmosphere. The check valve  228  shown in  FIG. 56  can be used for airhole  233 . However, the form of the airhole  233  is not limited to the check valve  228  shown in  FIG. 56 . If ink K is consumed and the container  1  inside becomes extremely negative pressure, air is introduced to the ventilation side ink chamber  123   a  from the outside of the container  1  by the airhole  233 , and the airhole  233  thus prevents the pressure inside the container  1  to be negative. Therefore, with the consumption of ink advanced, air is introduced to the ventilation side ink chamber  123   a  through the airhole  233 , and the level of liquid surface of ink K decreases. 
   The partition wall  193   a  is coupled with the top wall  1030  liquid-tightly. Therefore, even the ink is consumed, ink K is filled in the detection side ink chamber  123   b  in the container  1  until the level of liquid surface of ink K reaches to the lower end  193   aa  of the partition wall  193   a . When the ink consumption advances and the level of liquid surface of ink K reaches to the lower end  193   aa  of the partition wall  193   a , gas enters to the detection side ink chamber  123   b . Thereby the ink k remained in the detection side ink chamber  123   b  flows out to the ink supply port  2 , and the medium existed around the actuator  106  changes from ink K to atmosphere. Therefore, the actuator  106  can detect that the status inside the ink cartridge is in ink end status. Thus, it is the lower end  193   aa  to determine which level of the liquid surface of ink K to be a ink end. Furthermore, the volume of the detection side ink chamber  132   b  is determined by the width between the side wall  1010 , which extends substantially vertical to the ink surface, and the partition wall  193   a . Therefore, the ink quantity remains inside the container  1  when detecting the ink end can be set by the width between the side wall  1010  and the partition wall  193   a  and the height of the lower end  193   aa  in the direction vertical to the ink surface. 
   The volume of the detection side ink chamber  123   b  is preferably half or smaller than half of the volume of the ventilation side ink chamber  123   a . A capillary force such as to hold ink K does not work on the detection side ink chamber  123   b.    
   The actuator  106  can be used as a means of merely detecting the vibration without vibrating itself. Moreover, the detailed configuration of the airhole will be described in  FIG. 56 . 
   A packing ring  4  and a valve body  6  are provided in the ink supply port  2 . Referring to  FIG. 54 , the packing ring  4  is engaged with the ink supply needle  32  communicating with a recording head  31 , in a fluid-tight manner. The valve body  6  is constantly and elastically contacted against the packing ring  4  by way of a spring  5 . When the ink supply needle  32  is inserted, the valve body  6  is pressed by the ink supply needle  32  so as to open an ink passage, so that ink inside the container  1  is supplied to the recording head  31  via the ink supply port  2  and the ink supply needle  32 . On an upper wall of the container  1 , there is mounted a semiconductor memory means  7  which stores data on ink inside the ink cartridge. 
   If there is no partition wall  193   a  in the container  1 , bubbles may be generated by the waving of ink, which is caused by the vibration of ink cartridge generated by such as the scanning operation during the printing process. Then, there is a danger that the actuator  106  may detect mistakenly that there is enough ink in the container  1  if the ink attaches to the actuator  106  by the waving of ink even if there is little amount of ink in the container  1 . Moreover, there is also a danger that the actuator  106  may detect mistakenly that there is no ink if the bubble attaches to the actuator  106  even if the ink is filled in the container  1 . 
   However, according to the embodiment of the liquid container of the present embodiment, the partition wall prevents the waving of ink around the piezoelectric device even when the ink cartridge vibrates by such as the scanning operation during the printing process. By preventing the waving of ink around the piezoelectric device, the partition wall  193   a  prevents the generation of the bubbles. Furthermore, even the bubbles generate in the ventilation side ink chamber, the partition wall separates the ventilation side ink chamber and the detection side ink chamber air-tightly and liquid-tightly. Therefore, the partition wall prevents the bubbles to move close to the actuator  106  and contact with the actuator  106 . 
   There is no limitation of the size, thickness, shape, flexibility, and material for the partition wall. Therefore, the size of the partition wall can be made relatively larger or smaller. The thickness of the partition wall can be made relatively thicker or thinner. Furthermore, the shape of the partition wall can be square or rectangular. Preferably the shape, size and thickness of the partition wall is changed according to the shape of the ink cartridge. Furthermore, the partition wall can be made from the hard material or flexible material. For example, material such as plastic, tefron, nylon, polypropylene, or PET can be used for the partition wall. Preferably, the partition wall is made from the air-tight or liquid-tight material which does not pass through gas or liquid. Moreover, the container and the partition wall are made from same material so that the container and the partition wall can be formed in one body. The manufacturing process of the ink cartridge can thereby be reduced. 
     FIG. 53  is a perspective view of the ink cartridge which stores plural types of inks, viewed from an outside thereof, according to an embodiment.  FIG. 53  is a perspective view from the side of the top wall  1038  which is located upside of the liquid surface of ink K among the wall of the container  8 . A container  8  is divided into three ink chambers  9 ,  10  and  11 . Ink supply ports  12 ,  13  and  14  are formed for the respective ink chambers. On a top wall  1038  of the respective ink chambers  9 ,  10  and  11 , the respective actuators  15 ,  16  and  17  are mounted on the container  8  so that the actuators  15 ,  16 , and  17  can contact with the ink which is housed in each ink chambers via the through hole, not shown in the figure, provided on the container  8 . Partition walls, not shown in the figure, is provided each of inside of the ink container  9 ,  10  and  11  as similar to the ink cartridge shown in  FIG. 52 . The partition walls provided in each of ink chambers  9 ,  10 , and  11  separates the each ink chambers  9 ,  10 , and  11  into ventilation side ink chamber and detection side ink chamber. 
     FIG. 54  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 52  and  FIG. 53 . A carriage  30  capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit  33 , while the recording head  31  is provided in a lower face of the subtank unit  33 . Moreover, the ink supply needle  32  is provided in an ink cartridge mounting face side of the subtank unit  33 . In  FIG. 54 , the ink cartridge shown in  FIG. 52  and  FIG. 53  are used. However, the ink cartridge shown in other figures also can be used. 
   When the ink supply port  2  of the container  1  is inserted through the ink supply needle  32  of the subtank unit  33 , the valve body  6  recedes against the spring  5 , so that an ink passage is formed and the ink inside the container  1  flows into the ink chamber  34 . At a stage where the ink chamber  34  is filled with ink, a negative pressure is applied to a nozzle opening of the recording head  31  so as to fill the recording head with ink. Thereafter, the recording operation is performed. 
   When the ink is consumed in the recording head  31  by the recording operation, a pressure in the downstream of the flexible valve  36  decreases. Then, the flexible valve  36  is positioned away from a valve body  38  so as to become opened. When the flexible valve  36  is opened, the ink in the ink chamber  34  flows into the recording head  31  through the ink passage  35 . Accompanied by the ink which has flowed into the recording head  31 , the ink in the container  1  flows into the subtank unit  33  via the ink supply needle  32 . 
     FIG. 55  is a cross sectional view of an another embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. In an ink cartridge of the present embodiment, a top wall  1039 , which locates upside of the liquid surface of ink K, is sloped to the liquid surface of ink K. The actuators  106  are mounted on the top wall  1039  such that the actuator  106  can contacts with ink through the through hole  1   c  provided on the top wall  1039 . The partition wall  193   c  extends from the top wall  1039  downward to the ink surface. Furthermore, the present embodiment has a second partition wall  193   d  which extends from the top wall  10398  inside the detection side ink chamber  123   b  and separates the detection side ink chamber  123   b  at least into two detection side small ink chambers  1123   a  and  1123   b  such that ink housed in both of the detection side small ink chamber,  1123   a  and  1123   b  can communicate each other. Each of two actuators  106   a  and  106   b  is mounted on the top wall  1039  of each of the detection side small ink chambers  1123   a  and  1123   b , respectively. 
   The volume of the ventilation side ink chamber  123   a  which is close to the ink supply port  2  is larger than the volume of the detection side ink chamber  123   b  which is relatively far from the ink supply port  2 . Furthermore, the volume of the detection side small ink chamber  1123   a  which is close to the ink supply port  2  is larger than the volume of the detection side small ink chamber  1123   b  which is relatively far from the ink supply port  2  within the detection side ink chamber  123   b . Therefore, ink in the ventilation side ink chamber  123   a  is consumed at first. With consumption of ink advanced, the level of ink surface in the ventilation side ink chamber  123   a  decreases. On the other hand, because the partition wall  193   cc  and the top wall  1039  is coupled liquid-tightly or air-tightly, the detection side ink chamber  123   b  is filled with ink until the level of ink surface reaches to the lower end  193   cc  of the partition wall  193   c.    
   Next, if the ink surface in the ventilation side ink chamber  123   a  reaches to the lower end  193   cc  of the partition wall  193   c , ink in the detection side small ink chamber  1123   a  is beginning to be consumed because ink in the detection side small ink chamber  1123   a  flows out to the ink supply port  2 . With consumption of ink advanced, the level of ink surface in the detection side small ink chamber  1123   a  decreases. On the other hand, because the partition wall  193   dd  and the top wall  1039  is coupled liquid-tightly or air-tightly, the detection side small ink chamber  1123   b  is filled with ink until the level of ink surface reaches to the lower end  193   dd  of the partition wall  193   d . Finally, if the level of ink surface of the detection side small ink chamber  1123   a  reaches to the lower end  193   dd  of the partition wall  193   d , ink in the detection side small ink chamber  1123   b  is beginning to be consumed because ink in the detection side small ink chamber  1123   b  flows out to the ink supply port  2 . 
   Therefore, the actuators  106   a  and  106   b  can detect the ink consumption status step by step. Moreover, because the volume of the ink chambers are designed such that the volume decreases from the ventilation side ink chamber  123   a , which is nearest to the ink supply port  2 , to the detection side small ink chamber  1123   a  and further to the detection side small ink chamber  1123   b , which is farthest from the ink supply port  2 , the frequency of detecting an ink by the actuators  106   a  and  106   b  increases with the advance of ink consumption. Therefore, the frequency of detection of ink increases with the decreasing of residual quantity of ink. 
   The container of the ink cartridge shown in  FIG. 55  has one second partition wall. As other embodiment, the container can have a plurality of partition walls so that the detection side ink chamber  123   b  is separated into three or over detection side small ink chambers. A plurality of second partition walls separates the detection side ink chamber  123   b  into two or over detection side small ink chambers. Each of the volumes of the of the detection side small ink chambers  1123   b  can be varied gradually from the one side of the side wall to the other side of side wall which faces each other. Preferably, as shown in  FIG. 55 , each of the volume of the detection side small ink chambers decreases gradually from the detection side small ink chamber, which is relatively near to the ink supply port  2 , to the detection side small ink chamber, which is relatively far from the ink supply port  2 . Then, the actuator  106  can detects the process of gradual consumption of ink K inside the ink cartridge. 
   Moreover, because the volume of the ink chambers are designed such that the volume decreases from the detection side small ink chamber  1123   a , which is near to the ink supply port  2 , to the detection side small ink chamber, which is far from the ink supply port  2 , the time interval of detecting a decrease of ink by the actuator  106  gradually decreases as the ink cartridge shown in  FIG. 55 . Therefore, the frequency of detection of ink increases with the decreasing of residual quantity of ink. 
   Furthermore, the actuator  106   a  is mounted nearby the partition wall  193   c , and the actuator  106   b  is mounted nearby the partition wall  193   d . Therefore, even if the bubble G generates and enters into the detection side ink chamber  123   b  when the ink inside the ventilation side ink chamber  123   a  does not reach to the lower end  193   cc  of the partition wall  193   c , the bubble G stays in the upper side of boundary between the top wall  1039  and the partition wall  193   c  or the upper side of boundary between the top wall  1039  and the side wall  1030 . Therefore, the bubble G does not attaches to the actuator  106 . 
     FIG. 56  shows further other embodiment of the ink-cartridge using the actuator  106 . The ink cartridge  220 A shown in  FIG. 56(A)  has a first partition wall  222  provided such that it extends downward from the top face of the ink cartridge  220 A. Because there is a predetermined space between the lower end of the first partition wall  222  and the bottom face of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the bottom face of the ink cartridge  220 A. A second partition wall  224  is formed such that the second partition wall  224  extends upward from the bottom face of the ink cartridge  220 A on the more ink supply port  230  side of the first partition wall  222 . Because there is a predetermined space between the upper end of the second partition wall  224  and the top face of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the top face of the ink cartridge  220 A. 
   A ventilation side ink chamber  225   a  is formed relatively near to the airhole  233 . On the other hand, a detection side ink chamber  225   b  is formed relatively far from the airhole  233 . By the second partition wall  224 , the detection side ink chamber  225   b  and a detection side small ink chamber  227  are formed. The volume of the ventilation side ink chamber  225   a  is larger than the volume of the detection side ink chamber  225   b . A detection side small ink chamber  227  is formed by providing a gap, which can generate the capillary phenomenon, between the first partition wall  222  and the second partition wall  224 . Therefore, the ink in the ventilation side ink chamber  225   a  is collected to the detection side small ink chamber  227  by the capillary force of the detection side small ink chamber  227 . The first partition wall  222  can prevent that the gas or air bubble to enter into the detection side ink chamber  225   b . Furthermore, the ink level in the detection side ink chamber  225   b  can decrease steadily and gradually. Because the ventilation side ink chamber  225   a  is formed at more inner part of the detection side ink chamber  225   b , seen from the ink supply port  230 , the ink in the detection side ink chamber  225   b  is consumed after the ink in the ventilation side ink chamber  225   a  is consumed. 
   Because ink is supplied from the ventilation side ink chamber  225   a  to the detection side ink chamber  225   b  by the detection side small ink chamber  227 , the actuator  106  does not influenced by the rolling of ink caused by the rolling of the ink cartridge  220 A, and actuator  106  can thus reliably measure the ink residual quantity. Furthermore, because the detection side small ink chamber  227  holds ink, the detection side small ink chamber  227  can prevent ink to flow backward from the detection side ink chamber  225   b  to the ventilation side ink chamber  225   a.    
   The actuator  106  is mounted on the top wall  1013  of the ink supply port  230  side of the detection side ink chamber  225   b . The actuator  106  detects the ink consumption status inside the detection side ink chamber  225   b . The residual quantity of ink at the timing closed to the ink near end can be detected stably by mounting the actuator  106  on the side wall of the detection side ink chamber  225   b.    
   A airhole  233  is provided on the top wall  1013  of the ink cartridge  220 A. Moreover, a check valve  228  is provided on the airhole  233 . The leaking of ink outside the ink cartridge  220 A caused by the rolling of the ink cartridge  220 A can be prevented by the check valve  228 . Furthermore, the evaporation of ink from the airhole  233  of the ink cartridge  220 A can be prevented by providing the check valve  228  on the top face of the ink cartridge  220 A. If ink in the ink cartridge  220 A is consumed, and negative pressure inside the ink cartridge  220 A exceeds the pressure of the check valve  228 , the check valve  228  opens and introduces air into the ink cartridge  220 A. Then the check valve  228  closes to accelerate the drainage of ink from the ink cartridge  220 A. 
     FIG. 57  shows further another embodiment of the ink cartridge using the actuator  106 . An ink cartridge  180 A shown in  FIG. 57  has a partition wall  212   a  which extends downward from the top face  194   c  of the ink container  194 . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  212   a . Because lower end  212   aa  of the partition wall  212   a  and the bottom wall  1   a  of the container  194  have a predetermined space, the ventilation side ink chamber  213   a  and the detection side ink chamber  213   b  communicates with each other. The actuator  106  is mounted on the top wall  194   c  of the detection side ink chamber  213   b . The volume of the detection side ink chamber  213   b  is smaller than the volume of the ventilation side ink chamber  213   a . The volume of the detection side ink chamber  213   b  is preferably smaller than the half of the volume of the ventilation side ink chamber  213   a.    
   A buffer  214   a , that is a concave part for accepting the air bubble which enters to the ink cartridge  180 A is formed on the top wall  194   c  of the detection side ink chamber  213   b . In  FIG. 57 , the buffer  214   a  is formed as a concave part overhang upward from the top wall  194   c  of the container  194 . The buffer  214   a  accepts the air bubble which enters into the detection side ink chamber  213   b  mistakenly when the ink is filled in the detection side ink chamber  213   b . The buffer  214   a  thereby prevents the bubbles to attach to the actuator  106 . Therefore, the buffer  214   b  prevents the malfunction of the actuator  106  to detect the ink end wrongly by the attaching of air bubble to the actuator  106 . Furthermore, by adjusting the volume of the detection side ink chamber  213   b  by changing the length of the partition wall  212   a  or changing the width between the partition wall  212   a  and the side wall  194   b , the predetermined ink quantity remained after the detection of the ink end can be changed. 
     FIG. 58  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 B shown in  FIG. 58  has a partition wall  212   b  which is formed in L-shape. The partition wall  212   f  extends from a top wall  194   c . A lower end  212   bb  of the partition wall  212   b  is longer than the lower end  212   aa  of the partition wall  212   a  in the embodiment shown in  FIG. 57 . Therefore, gas existed in the ventilation side ink chamber  213   a  is difficult to enter into the detection side ink chamber  213   b . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly caused by the attaching of bubble to the actuator  106  can be further prevented. Furthermore, a gap is provided between the lower end  212   bb  and the bottom wall  1   a . A capillary force, which can hold ink, does not work on the gap provided between the lower end  212   bb  and the bottom wall  1   a.    
     FIG. 59  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 C shown in  FIG. 59  has a partition wall  212   c  which is sloped toward the ink surface. The partition wall  212   c  extends from a top wall  194   c . The distance between the side wall  194   b  of the ink cartridge  180 C and the partition wall  212   c  narrows toward downside. Therefore, gas existed in the ventilation side ink chamber  213   a  is difficult to enter into the detection side ink chamber  213   b . Therefore, the malfunction caused by the attaching of bubble to the actuator  106  can be further prevented. Furthermore, a gap is provided between the lower end  212   cc  and the bottom wall  1   a  of the container  194 . A capillary force, which can hold ink, does not work on the gap provided between the lower end  212   cc  of the partition wall  212   c  and the side wall  194   b.    
     FIG. 60  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 D shown in  FIG. 60  has a first partition wall  212   d  which extends downward from the top face  194   c  of the ink container  194 . Furthermore, a second wall extends from the first partition wall  212   d  toward the side wall  194   b  substantially parallel to the ink surface. The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the first partition wall  212   d . Furthermore, the second partition wall  212   e  separates the detection side ink chamber into a first detection side ink chamber  213   c  and a second detection side ink chamber  213   d . A gap is provided between the bottom wall  1   a  and the first partition wall  212   d . Furthermore, a gap is provided between the side wall  194   b  and the one end  212   ee  of the second partition wall  212   e . A concave part is provided on a part of top wall  194   c  to form a buffer  214   a  which accepts the bubble. 
   One end of the second partition wall  212   e , which extends from the partition wall  212   d  toward the side wall  194   b , extends until to the position where just under the buffer  214   b . Therefore, first, the first partition wall  212   d  prevents the entering of bubble into the first detection side ink chamber  213   c . If the bubble enters into the detection side ink chamber  213   c  mistakenly, the bubble is introduced to the position which is just under the buffer  214   a  by the second partition wall  212   e . Therefore, the bubble is caught by the buffer  214   a . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly by the attaching of bubble to the actuator  106 , which is provided in the second detection side ink chamber  213   d , can be further prevented. 
     FIG. 61  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 E shown in  FIG. 61  has a partition wall  212   a  as same as the partition wall  212   a  of  FIG. 57 . The partition wall  212   a  extends downward from the top face  194   c  of the ink container  194 . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  212   a . A gap is provided between the bottom wall  1   a  and the partition wall  212   a . Furthermore, a concave part is provided on a part of top wall  194   c  to form a buffer  214   b  which accepts the bubble. A tapered face  1040  is provided between the buffer  214   b  and the actuator  106 . 
   Therefore, first, the partition wall  212   a  prevents the entering of bubble into the detection side ink chamber  213   b . If the bubble enters into the detection side ink chamber  213   b  mistakenly, the bubble is directly caught by the buffer  214   a  or introduced to the buffer  214   b  along the tapered face  1040 . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly by the attaching of bubble to the actuator  106  can be further prevented. The shape and size of the buffer can be other arbitrary shape and size. 
     FIG. 62  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 F shown in  FIG. 62  has a protruding part  214   f , which protrudes inside the container  194 , on a part of the top wall  194   c . The actuator  106  is mounted on the bottom part of the protruding part  214   f . A partition wall  212   f  extends downward from the top face  194   c . A buffer  214   c  is provided for each of the position between the actuator  106  and the partition wall  212   f  and between the actuator  106  and the side wall  194   b . Therefore, the periphery of the actuator  106  is surrounded by the buffer  214   c.    
     FIG. 63  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 G shown in  FIG. 63  has a partition wall  212  extends downward from the top face  194   c . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  212   g . Uneven part is provided on the top wall  194   c , and two actuators  106  are mounted on the protruding part which protrudes inside the detection side ink chamber  213   b . The concave part of the top wall  194   c  works as a buffer  214   c  which accepts bubble. 
     FIG. 64  shows further other embodiment of the ink cartridge  180 . The ink cartridge  1801  shown in  FIG. 64  has a plurality of partition walls  212   h ,  212   i ,  212   j , and  212   k , each of which extends downward from the top face  194   c  of the ink container  194 . The partition wall  212   h  is first partition wall, and the partition walls  212   i ,  212   j , and  212   k  are the second partition walls. Because each of lower ends  212   hh ,  212   ii ,  212   jj , and  212   kk  of each of the partition walls  212   h ,  212   i ,  212   j , and  212   k  and the bottom wall  1   a  of the container  194  have a predetermined gap, the bottom part of the container  194  communicates with each other. The ink cartridge  180 I has a ventilation side ink chamber  213   a  and a plurality of detection side small ink chambers  213   h ,  213   i ,  213   j , and  213   k  separated by the each of plurality of partition walls  212   h ,  212   i ,  212   j  and  212   k . The bottom part of the ventilation side ink chamber  213   a  and a plurality of the detection side small ink chambers  213   h ,  213   i ,  213   j , and  213   k  communicates with each other. Each of the actuators  106   h ,  106   i ,  106   j , and  106   k  is mounted on the top face  194   c  of each of the plurality of the detection side small ink chambers  213   h ,  213   i ,  213   j , and  213   k , respectively. Each of the actuators  106   h ,  106   i ,  106   j , and  106   k  is arranged on substantially center of the top face  194   c  of each of the plurality of the detection side small ink chambers  213   h ,  213   i ,  213   j , and  213   k , respectively. The volume of the ink chamber is arranged such that the volume of the ventilation side ink chamber  213   a  which locates ink supply port  187  side is the largest. Moreover, the volume of the ink chamber gradually decreases as the distance from the ink supply port  187  increases. Therefore, the volume of the detection side small ink chamber  213   k  which is farthest from the ink supply port  187  is the smallest among the volume of the ink chambers. 
   Because gas is introduced from the airhole  233 , ink is consumed from the ventilation side ink chamber  213   a  of the ink supply port  187  side to the detection side ink chamber  213   k . For example, the ink in the ventilation side ink chamber  213   a  which is nearest to the ink supply port  187  is consumed, and during the ink level of the ventilation side ink chamber  213   a  decreases, the other detection side small ink chambers are filled with ink. When the ink level in the ventilation side ink chamber  213   a  reaches to the lower end  212   hh  of the partition wall  212   h , air enters into the detection side small ink chamber  213   h , and then the ink in the detection side small ink chamber  213   h  is beginning to be consumed. At this time, ink is filled in the detection side small ink chamber  213   i ,  213   j , and  213   k . Furthermore, if the ink level in the detection side small ink chamber  213   h  reaches to the lower end  212   ii  of the partition wall  212   i , air enters into the detection side small ink chamber  213   i , and then the ink in the detection side small ink chamber  213   i  is beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber  213   a  to the detection side small ink chamber  213   k.    
   Each of the actuators  106   h ,  106   i ,  106   j , and  106   k  is mounted on the top wall  194   c  of each of the detection side small ink chambers. Therefore, the actuators  106   h ,  106   i ,  106   j , and  106   k  can detect the decrease of the ink quantity step by step. Furthermore, the volume of the ink chambers decreases from the ventilation side ink chamber  213   a , which is near to the ink supply port  187 , to the detection side small ink chamber  213   k  gradually. Therefore, the time interval of detecting the decrease of the ink quantity gradually decreases. Therefore, the frequency of the ink quantity detection can be increased as the ink end is drawing near. 
     FIG. 65  shows further other embodiment of the ink cartridge  180 .  FIG. 65  shows a cross section of an ink cartridge  180 J. The semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610  in the ink cartridge  180 J. 
   The semiconductor memory device  7  can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610 , the mounting process can be finished at one time during mounting the semiconductor memory device  7  and the actuator  106  on the ink cartridge  180 C. Moreover, the working process during the manufacturing of the ink cartridge  180 C and the recycling of the ink cartridge  180 C can be simplified. Furthermore, the manufacturing cost of the ink cartridge  180 C can be reduced because the numbers of the parts can be reduced. Furthermore, a partition wall  212 J extends from the top wall  194   c  downward to the ink surface. The partition wall  212 J prevents the waving of ink or bubbling. The partition wall  212 J thereby prevents the malfunction of the actuator  106 . 
   The actuator  106  detects the ink consumption status inside the container  194 . The semiconductor memory device  7  stores the information of ink such as residual quantity of ink detected by the actuator  106 . That is, the semiconductor memory device  7  stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator  106  when detecting the ink consumption status. The semiconductor memory device  7  previously stores the resonant frequency of when ink inside the container  194  is full, that is, when ink is filled in the container  194  sufficiently, or when ink in the container  194  is end, that is, ink in the container  194  is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container  194  is full status or end status can be stored when the ink container is mounted on the ink jet recording apparatus for the first time. Moreover, the resonant frequency when the ink inside the container  194  is full status or end status can be stored during the manufacturing of the container  194 . Because the unevenness of the detection of the residual quantity of ink can be compensated by storing the resonant frequency when the ink inside the container  194  is full status or end status in the semiconductor memory device  7  previously and reading out the data of the resonant frequency at the ink jet recording apparatus side, it can be accurately detected that the residual quantity of ink is decreased to the reference value. 
     FIG. 66  shows further other embodiment of the ink cartridge  180 . The ink cartridge  180 K shown in  FIG. 66  has a plurality of partition walls  212   m ,  212   n ,  212   p , and  212   q , each of which extends downward from the top face  194   c  of the ink container  194 . The partition wall  212   m  is the first partition wall, and the partition walls  212   n ,  212   p , and  212   q  are the second partition walls. Because each of lower ends  212   mm ,  212   nn ,  212   pp , and  212   qq  of the partition walls  212   m ,  212   n ,  212   p , and  212   q , respectively, and the bottom wall of the container  194  has a predetermined gap, the bottom part of the container  194  communicates with each other. Moreover, the length of the partition walls  212   m ,  212   n ,  212   p , and  212   q  increases from the side near to the airhole  233  in order. Therefore, each of the gap between the lower ends  212   mm ,  212   nn ,  212   pp , and  212   qq  and the bottom wall  1   a  narrows in the order of  212   m ,  212   n ,  212   p , and  212   q , sequentially. 
   Furthermore, the ink cartridge  180 K has a ventilation side ink chamber  213   a  and a plurality of detection side small ink chamber  213   m ,  213   n ,  213   p , and  213   q  separated by the each of plurality of partition walls  212   m ,  212   n ,  212   p  and  212   q . The bottom part of the ventilation side ink chamber  213   a  and a plurality of the detection side small ink chambers  213   m ,  213   n ,  213   p , and  213   q  communicates with each other. Each of the actuators  106   m ,  106   n ,  106   p , and  106   q  is mounted on the top face  194   c  of each of the plurality of the detection side small ink chambers  213   m ,  213   n ,  213   p , and  213   q , respectively. Each of the actuators  106   m ,  106   n ,  106   p , and  106   q  is arranged on substantially center of the top face  194   c  of each of the plurality of the detection side small ink chambers  213   m ,  213   n ,  213   p , and  213   q , respectively. 
   If ink is consumed, gas is introduced from the airhole  233 . Therefore, ink is consumed from the ventilation side ink chamber  213   a  which is near to the airhole  233  to the detection side ink chamber  213   q . For example, the ink in the ventilation side ink chamber  213   a  which is nearest to the airhole  233  is consumed, and during the ink level of the ventilation side ink chamber  213   a  decreases, the other detection side small ink chambers are filled with ink. When the ink level in the ventilation side ink chamber  213   a  reaches to the lower end  212   mm  of the partition wall  212   m , air enters into the detection side small ink chamber  213   m , and then the ink in the detection side small ink chamber  213   m  is beginning to be consumed. At this time, ink is filled in the detection side small ink chamber  213   n ,  213   p , and  213   q . Furthermore, if the ink level in the detection side small ink chamber  213   m  reaches to the lower end  212   nn  of the partition wall  212   n , air enters into the detection side small ink chamber  213   n , and then the ink in the detection side small ink chamber  213   n  is beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber  213   a  to the detection side small ink chamber  213   q.    
   Because the gap between the each of the lower ends and the bottom wall  1   a  narrows gradually in the order from the lower ends  212   mm ,  212   nn ,  212   pp , and  212   qq , ink is consumed in the order from the ventilation side ink chamber  213   a , detection side small ink chamber  212   m ,  212   n ,  212   p , and  212   q , sequentially. Therefore, the gas is difficult to enter mistakenly into the ink chambers in the same order mentioned above. For example, even if gas enters into the detection side small ink chamber  213   m  and  213   n  mistakenly, and the actuator  106  detects the ink end mistakenly, the partition walls  212   p  and  212   q , which is longer than the partition walls  212   m  and  212   n , prevents the gas to enter into the detection side small ink chamber  213   p  and  213   q . Therefore, the actuators  106   p  and  106   q  do not mistakenly detect the ink end. Thus, in the present embodiment, the actuator  106   q  detects the ink end finally and most reliably. 
   Furthermore, because the partition walls  212   m ,  212   n ,  212   p , and  212   q  prevent the waving of ink, the partition walls  212   m ,  212   n ,  212   p , and  212   q  also prevent the generation of the bubble. 
   Moreover, the intervals between each of the partition walls  212   m ,  212   n ,  212   p , and  212   q  with each other can be equal, and the interval between the partition wall  212   q  and the side wall  194   b  of the container  1  can be equal. In this case, the capacity of each of the detection side small ink chambers  213   m ,  213   n ,  213   p , and  213   q  can be adjusted by adjusting the length of the partition walls  212   m ,  212   n ,  212   p , and  212   q.    
     FIG. 67  shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator  106 . In the present embodiment, the ink cartridge  180 A shown in  FIG. 57  is used. However, the ink cartridge in any of the ink cartridge shown in  FIG. 58  to  FIG. 64  also can be used. Furthermore, the ink cartridge of the other form also can be used. A plurality of ink cartridges  180 A is mounted on the ink jet recording apparatus which has a plurality of ink introducing members  182  and a holder  184  each corresponding to the each of ink cartridge  180 , respectively. Each of the plurality of ink cartridges  180 A contains different types of ink, for example, different color of ink. The actuator  106 , which detects at least acoustic impedance, is mounted on the each of top wall of the plurality of ink cartridge  180 A. The actuator  106  and a partition wall  212   a  are provided for each top wall of the plurality of ink cartridge  180 A. The residual quantity of ink in the ink cartridge  180  can be detected by mounting the actuator  106  on the ink cartridge  180 . The partition wall  212   a  prevent&amp; the waving and bubbling of ink. 
     FIG. 68  shows a detail around the head member of the ink jet recording apparatus. In the present embodiment, the ink cartridge  180 A shown in  FIG. 57  is used. However, the ink cartridge in any of the ink cartridge shown in  FIG. 58  to  FIG. 64  also can be used. Furthermore, the ink cartridge of the other form also can be used. The ink jet recording apparatus has an ink introducing member  182 , a holder  184 , a head plate  186 , and a nozzle plate  188 . A plurality of nozzle  190 , which jet out ink, is formed on the nozzle plate  188 . The ink introducing member  182  has an air supply hole  181  and an ink introducing inlet  183 . The air supply hole  181  supplies air to the ink cartridge  180 . The ink introducing inlet  183  introduces ink from the ink cartridge  180 A. The ink cartridge  180 A has an air introducing inlet  185  and an ink supply port  187 . The air introducing inlet  185  introduces air from the air supply hole  181  of the ink introducing member  182 . The ink supply port  187  supplies ink to the ink introducing inlet  183  of the ink introducing member  182 . By introducing air from the ink introducing member  182  to the ink cartridge  180 , the ink cartridge  180  accelerates the supply of ink from the ink cartridge  180 A to the ink introducing member  182 . The holder  184  communicates ink, which is supplied from the ink cartridge  180 A through the ink introducing member  182 , to the head plate  186 . Ink is supplied to the head from the ink cartridge  180 A through the ink introducing member  182  and discharged to the recording medium from nozzle. In this way, the ink jet recording apparatus performs the printing on the recording medium. 
     FIG. 69  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink as an embodiment of the liquid container according to the present invention. An ink cartridge shown in  FIG. 69  is based on the method that detects the position of the liquid surface or an existence of liquid inside a liquid container by detecting a resonant frequency by measuring the counter electromotive force generated by the residual vibration remained in the vibrating section among the above mentioned method. The actuator  106  is used for an embodiment of the liquid censor that detects liquid. The ink cartridge of the embodiment shown in  FIG. 69  comprises a container  1  which contains liquid K and includes top wall  1030  located upside of the liquid surface of ink K, an ink supply port  2  which supplies liquid K outside the container  1 , an actuator  106  which detects ink consumption status inside the container  1 , and a first partition wall  193   a  which partitions at least two ink chamber such that ink K in both of the ink chamber can communicate with each other inside the container  1 . 
   At least two ink chambers include a ventilation side ink chamber  123   a  which communicate with atmosphere and the detecting side ink chamber  123   b . The actuator  106  is mounted on the top wall  1030  of the ink chamber  123   b , and a porous member  1000  is provided in the detection side ink chamber  123   b  as a buffer member. A coarse buffer material such as filter can be used instead of the porous member  1000 . 
   The airhole  2   c  is provided on the top wall  1030  of the ventilation side ink chamber  123   a  which ventilates with atmosphere. The check valve  228  shown in  FIG. 85  can be used for airhole  2   c . However, the form of the airhole  2   c  is not limited to the check valve  228  shown in  FIG. 85 . If ink K is consumed and the container  1  inside decreases, air is introduced to the ventilation side ink chamber  123   a  from the outside of the container  1  by the airhole  2   c , and the airhole  2   c  thus prevents the pressure inside the container  1  to be negative. Therefore, with the consumption of ink advanced, air is introduced to the ventilation side ink chamber  123   a  through the airhole  2   c , and the level of liquid surface of ink K decreases. 
   The partition wall  193   a  is coupled with the top wall  1030  and side wall, not shown in the figure, liquid-tightly. Therefore, even the ink is consumed, ink K is sufficiently absorbed in the porous member  1000  and filled in the detection side ink chamber  123   b  in the container  1  until the level of liquid surface of ink K reaches to the lower end  193   aa  of the partition wall  193   a . When the ink consumption advances, and the level of liquid surface of ink K reaches to the lower end  193   aa  of the partition wall  193   a , gas enters to the detection side ink chamber  123   b . The ink k absorbed by the porous member  1000  in the detection side ink chamber  123   b  thereby flows out to the ink supply port  2 , and the medium existed around the actuator  106  changes from ink to atmosphere. Therefore, the actuator  106  can detect that the status inside the ink cartridge is in ink end status. Thus, it is the lower end  193   aa  to determine which level of the liquid surface of ink K to be a ink end. Furthermore, the volume of the detection side ink chamber  132   b  is determined by the position of partition wall  193   a  to the top wall  1030 . Therefore, the ink quantity remains inside the container  1  when detecting the ink end can be set by the position of the partition wall  193   a  to the top wall  1030  and the height of the lower end  193   aa  in the direction vertical to the ink surface. 
   Here, the case of using an on-carriage type ink jet recording apparatus, the ink cartridge of which is move together with recording head during the scanning process will be considered. If there is no partition wall  193   a  in the container  1 , or if no buffer material is provide around the actuator  106 , bubbles may be generated by the waving of ink, which is caused by the vibration of ink cartridge generated by such as the scanning operation during the printing process because the ink cartridge moves together with recording head. Then, there is a danger that the actuator  106  may detect mistakenly that there is enough ink in the container  1  if the ink attaches to the actuator  106  by the waving of ink even if there is little amount of ink in the container  1 . Moreover, there is also a danger that the actuator  106  may detect mistakenly that there is no ink if the bubble attaches to the actuator  106  even if the ink is filled in the container  1 . 
   However, according to the embodiment of the liquid container of the present embodiment, the partition wall prevents the waving of ink around the piezoelectric device even when the ink cartridge vibrates by such as the scanning operation during the printing process. By preventing the waving of ink around the piezoelectric device, the partition wall  193   a  prevents the generation of the bubbles. Furthermore, even the bubbles generate in the ventilation side ink chamber, the partition wall separates the ventilation side ink chamber and the detection side ink chamber. Therefore, the partition wall prevents the bubbles to move close to the actuator  106  and contact with the actuator  106 . 
   Moreover, the porous member  1000  is provided on the detection side ink chamber  123   b  to intervene between the actuator  106  and the ventilation side ink chamber  123   a . Therefore, even if the bubbles generated in the ventilation side ink chamber  123   a  enters into the detection side ink chamber  123   b  mistakenly, the porous member  1000  prevents the bubbles to move close to the actuator  106  and contact with the actuator  106 . 
   Furthermore, because the porous member  1000  is provided in the detection side ink chamber  123   b , ink inside the detection side ink chamber  123   b  does not wave by the vibration of the actuator  106 . Therefore, the actuator  106  can reliably and stably detect the ink consumption status in the container  1 . 
   The volume of the detection side ink chamber  123   b  is preferably half or smaller than half of the volume of the ventilation side ink chamber  123   a . The detection side ink chamber  123   b  preferably has a width in a degree not to arise a capillary force such as to hold ink K. 
   The actuator  106  can be used as a means of merely detecting the vibration without vibrating itself. 
   There is no limitation of the size, thickness, shape, flexibility, and material for the partition wall of the ink cartridge of the embodiment of the liquid container according to the present embodiment. Therefore, the size of the partition wall can be made further larger or smaller. The thickness of the partition wall can be made further thicker or thinner. Furthermore, the shape of the partition wall can be square or rectangular. Furthermore, the partition wall can be made from the hard material or flexible material. For example, material such as plastic, tefron, nylon, polypropylene, or PET can be used for the partition wall. Preferably, the partition wall is made from the air-tight or liquid-tight material which does not pass through gas or liquid. Moreover, the container and the partition wall are made from same material so that the container and the partition wall can be formed in one body. The manufacturing process of the ink cartridge can thereby be reduced. 
   Moreover, there is no limitation of the size, thickness, shape, flexibility, and material for the porous member of the ink cartridge of the embodiment of the liquid container according to the present embodiment. Therefore, the size of the porous member can be made further larger or smaller. The thickness of the porous member can be made further thicker or thinner. Furthermore, the shape of the porous member can be cubic or rectangular parallelepiped. 
   Moreover, there is no limitation of the shape of the hole included in the porous member. Therefore, for example, the negative pressure or capillary force of the porous member, which includes the hole of spherical shape, can be increased by reducing the size of the hole. On the other hand, the negative pressure or capillary force of the porous member, which includes the hole of spherical shape, can be decreased by enlarging the size of the hole. Preferably, the porous member  1000  is made from a flexible material such as sponge. Moreover, it is preferable to set the diameter of hole of the porous member to predetermined diameter so that the porous member can absorb ink from a cavity, referring to  FIG. 19 , which is formed in the actuator  106 , and introduce ink to ink supply port, referring to  FIG. 1 . 
   The porous member  1000  of the embodiment shown in  FIG. 69  has a shape of rectangular parallelepiped. The porous member  1000  is filled in the detection side ink chamber  123   b  such that the porous member  1100  fills from the periphery of the actuator  106  to the bottom wall  1   a  which is located below the ink surface in the ink cartridge. 
   A packing ring  4  and a valve body  6  are provided in the ink supply port  2 . Referring to  FIG. 70 , the packing ring  4  is engaged with the ink supply needle  32  communicating with a recording head  31 , in a fluid-tight manner. The valve body  6  is constantly and elastically contacted against the packing ring  4  by way of a spring  5 . When the ink supply needle  32  is inserted, the valve body  6  is pressed by the ink supply needle  32  so as to open an ink passage, so that ink inside the container  1  is supplied to the recording head  31  via the ink supply port  2  and the ink supply needle  32 . On an upper wall of the container  1 , there is mounted a semiconductor memory means  7  which stores data on ink inside the ink cartridge. 
     FIG. 71  is a cross sectional view of a further another embodiment of an ink cartridge as an embodiment of the liquid container according to the present invention. An ink cartridge of the present embodiment has a top wall  1030 , which locates upside of the liquid surface of ink K. The actuators  106  are mounted on the top wall  1030  such that the actuator  106  can contacts with ink through the through hole  1   c  provided on the top wall  1030 . A first partition wall  193   c  extends from the top wall  1030  downward to the ink surface. Furthermore, the present embodiment has a second partition wall  193   d  which extends from the top wall  1030  inside the detection side ink chamber  123   b  and separates the detection side ink chamber  123   b  at least into two detection side small ink chambers  1123   a  and  1123   b  such that ink housed in both of the detection side small ink chamber  1123   a  and  1123   b  can communicate each other. The actuator  106  is mounted on the top wall  1030  of each of the detection side small ink chambers  1123   a  and  1123   b , respectively. 
   Furthermore, a porous member  1002  and a porous member  1003  are provided to each of the inside of the detection side small ink chamber  1123   a  and the detection side small ink chamber  1123   b.    
   Because gas is introduced from the airhole  128 , ink is consumed from the ventilation side ink chamber  123   a , which is near to the airhole  128 , to the detection side small ink chamber  1123   b , which is far from the airhole  128 . Therefore, during ink in the ventilation side ink chamber  123   a  which is nearest to the airhole  128  is consumed, the detection side ink chamber  123   b  is filled with ink. When the ink level in the ventilation side ink chamber  123   a  reaches to the lower end  193   cc  of the partition wall  193   c , air enters into the detection side small ink chamber  1123   a , and then the ink in the detection side small ink chamber  1123   a  is beginning to be consumed. At this time, ink is filled in the detection side small ink chamber  1123   b . Furthermore, if the ink level in the detection side small ink chamber  1123   a  reaches to the lower end  193   dd  of the second partition wall  193   d , air enters into the detection side small ink chamber  1123   b , and then the ink in the detection side small ink chamber  1123   b  is beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber  123   a  to the detection side small ink chamber  1123   b.    
   Because each of the actuators  106  is mounted on the top wall  1030  of each of the detection side small ink chambers  1123   a  and  1123   b , the actuators  106  can detect the decrease of the ink quantity step by step. Furthermore, the volume of the detection side ink chamber  123   b  is smaller than the volume of the ventilation side ink chamber  213   a . Furthermore, the volume of the detection side small ink chamber  1123   a  and  1123   b  gradually decreases from the detection side small ink chamber  1123   a  which is near to the airhole  128  to the detection side small ink chamber  1123   b , which is far from the airhole  128 . Therefore, the time interval of detecting the decrease of the ink quantity gradually decreases. The frequency of the ink quantity detection can thereby be increased as the ink end is drawing near. 
     FIG. 72  shows further another embodiment of the ink cartridge using the actuator  106 . An ink cartridge  180 A shown in  FIG. 72  has a partition wall  212   a  which extends downward from the top face  194   c  of the ink container  194 . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  212   a . Because lower end  212   aa  of the partition wall  212   a  and the bottom wall  1   a  of the container  194  have a predetermined space, the ventilation side ink chamber  213   a  and the detection side ink chamber  213   b  communicates with each other. 
   A buffer member  1005   a  is provided to block the communicating port between the ventilation side ink chamber  213   a  and the detection side ink chamber  213   b . A filter-like material, which includes many holes on its surface, can be used for buffer member  1050   a  if the buffer member closes the communicating port. Furthermore, the buffer member can be porous member. Therefore, the ventilation side ink chamber  213   a  and the detection side ink chamber  123   b  communicates each other through the buffer member  1005   a . Because the buffer member  1005   a  is made from porous material, the buffer material pass through gas and liquid. However, if the buffer member  1005   a  holds liquid by the capillary force, the buffer member becomes airtight. Therefore, the buffer member  1050   a  can suppress bubbles to passing through the buffer member  1050   a . Thus, the buffer member  1050   a  can prevents the bubbles, which is generated in the ventilation side ink chamber  213   a , to enter inside the detection side ink chamber  213   b  and attach to the actuator  106 . 
   The actuator  106  is mounted on the top wall  194   c  of each of the ventilation side ink chamber  213   a  and the detection side ink chamber  213   b . The volume of the detection side ink chamber  213   b  is smaller than the volume of the ventilation side ink chamber  213   a . The volume of the detection side ink chamber  213   b  is smaller than the half of the volume of the ventilation side ink chamber  213   a  in the ink cartridge of according to the present embodiment. 
   A buffer  214   a , that is a concave part for accepting the air bubble which enters to the ink cartridge  180 A is formed on the top wall  194   c  of the detection side ink chamber  213   b . In  FIG. 72 , the buffer  214   a  is formed as a concave part overhang upward from the top wall  194   c  of the container  194 . The buffer  214   a  accepts the air bubble which enters into the detection side ink chamber  213   b  mistakenly when the ink is filled in the detection side ink chamber  213   b . The buffer  214   a  thereby prevents the bubbles to attach to the actuator  106 . Therefore, the buffer  214   b  prevents the malfunction of the actuator  106  to detect the ink end wrongly by the attaching of air bubble to the actuator  106 . Furthermore, the level of ink surface on which the actuator  106  detects the ink end can be changed by changing the length of the partition wall  212   a . Furthermore, by changing the width between the partition wall  212   a  and the side wall  194   b , the predetermined ink quantity remained after the detection of the ink end can be changed. 
   The ink cartridge  180 B shown in  FIG. 73  fills a porous member  1005   b  in the detection side ink chamber  123   b  of the ink cartridge  180 A shown in  FIG. 72 . The porous member  1005   b  is filled inside the detection side ink chamber  213   b  from the top wall  194   c  to the bottom wall  194   a . The porous member  1005   b  contacts with the actuator  106 . There is a case that the actuator  106  malfunctions by the entering of the air inside the detection side ink chamber  213   b  when the ink cartridge fall down or when the detection side ink chamber  213   b  moves back and forth with the carriage. If the porous member  1005   b  is provided on the detection side ink chamber  213   b , the porous member  1005   b  captures air to prevent entering of air into the actuator  106 . Furthermore, because the porous member  1005   b  holds ink, the porous member  1005   b  can prevent the actuator  106  to malfunction as detecting the ink end status as ink exist status which is caused by attaching of the ink on the actuator  106  when the ink container rolls. The ink quantity which can be consumed after the detection of the ink end can be changed by adjusting the volume of the detection side ink chamber  213   b  by changing the width between the side wall  194   b  and the partition wall  212   a . Furthermore, the level of ink surface on which the actuator  106  detects the ink end can be changed by adjusting the height of the lower end  212   aa  of the partition wall  212   a  from the ink surface. 
     FIG. 74  shows an ink cartridge  180 C, the porous member of which is constituted by two kinds of porous members  1005   c  and  1005   d  having a different hole diameter with each other. The porous member  1005   c  is located closer to the actuator  106  than the porous member  1005   d . The hole diameter of the porous member  1005   c  is larger than the hole diameter of the porous member  1005   d . The capillary force of the porous member  1005   d , which has small hole diameter, is larger than the capillary force of the porous member  1005   c , which has large hole diameter. Therefore, the ink, which once flows from the porous member  1005   c  to the porous member  1005   d , does not flow backward to the porous member  1005   c  because the capillary force works at the porous member  1005   d . Therefore, the porous members  1005   c  and  1005   d  prevents the attaching of ink to the actuator  106  by the waving of ink and thereby prevents the malfunction of the actuator  106  to detect the ink end status as ink exist status. The porous member  1005   c  can be formed by the material which has a lower affinity for liquid than the affinity for liquid of the material which forms the porous member  1005   d.    
     FIG. 75  shows a cross section of an ink cartridge  180 D which is further other embodiment of the ink cartridge  180  using actuator  106 . Ribs  1100 , which protrudes inside the ink container  194 , are provided on the bottom side of the side wall  194   b  of the detection side ink chamber  213   b . The porous member  1005   b  which is provided inside the detection side ink chamber  213   b  is gradually compressed by the ribs  1100  such that the area of the cross section on the horizontal plane of the porous member  1005   b  gradually decreases downwards along the vertical direction. Therefore, the hole diameter of the porous member  1005   b  decreases gradually in the direction downward to the ink surface. Because the hole diameter of the lower part of the porous member  1005   b  reduced by the ribs  1100 , the ink, which once flows into the lower part of the porous member  1005   b  does not flow backward to the upside of the porous member  1005   b  by the capillary force. Furthermore, the porous member  1005   b  of the present embodiment prevents ink to attach to the actuator  106 , which is mounted on the top wall  194   c , by the waving of ink. Therefore, the malfunction of the actuator  106  to detect the ink end status as the ink exist status can be prevented. 
     FIG. 76(A)  and  FIG. 76(B)  shows further another embodiment of the ink cartridge using actuator  106 .  FIG. 76(A)  is a cross sectional view along the longitudinal direction of a ink cartridge  180 E.  FIG. 76(B)  shows B-B cross sectional view of the ink cartridge  180 E shown in  FIG. 76(A) . A taper  1110  is provided on the lower side of the side wall of the detection side ink chamber  213   b . The width of the detection side ink chamber  213   b  gradually narrows downward along the vertical direction by the taper  1110 . Therefore, the porous member  1005   b  is compressed gradually by the taper  1110  such that the area of the cross section on the horizontal plane of the porous member  1005   b  gradually decreases downwards along the vertical direction. Therefore, lower side of the hole diameter of the porous member  1005   b  gradually becomes smaller than the upper side of the hole diameter of the porous member  1005   b  by the taper  1110 . Because the hole diameter of the lower part of the porous member  1005   b  reduced by the taper  1110 , the ink, which once flows into the lower part of the porous member  1005   b  does not flow backward to the upside of the porous member  1005   b  by the capillary force. Furthermore, the porous member  1005   b  of the present embodiment prevents ink to attach to the actuator  106 , which is mounted on the top wall  194   c , by the waving of ink. Therefore, the malfunction of the actuator  106  to detect the ink end status as the ink exist status can be prevented. 
     FIG. 77  shows further another embodiment of the ink cartridge using actuator  106 . An ink cartridge  180 F shown in  FIG. 77  has a partition wall  212   c  which is sloped toward the ink surface. A porous member  1105   e  is filled in the detection side ink chamber  213   b . The partition wall  212   c  extends from a top wall  194   c . The distance between the side wall  194   b  of the ink cartridge  180 C and the partition wall  212   c  gradually narrows toward downside. Therefore, the porous member  1005   e  is compressed gradually by the partition wall  212   c  such that the area of the cross section on the horizontal plane of the porous member  1005   b  gradually decreases toward downside. Therefore, lower side of the hole diameter of the porous member  1005   e  gradually becomes smaller than the upper side of the hole diameter of the porous member  1005   e  by the partition wall  212   c . Because the hole diameter of the lower part of the porous member  1005   e  is reduced by the partition wall  212   c , the ink, which once flows into the lower part of the porous member  1005   e  does not flow backward to the upside of the porous member  1005   e  by the capillary force. Furthermore, the porous member  1005   e  of the present embodiment prevents ink to attach to the actuator  106 , which is mounted on the top wall  194   c , by the waving of ink. Therefore, the malfunction of the actuator  106  to detect the ink end status as the ink exist status can be prevented. 
   Moreover, gas existed in the ventilation side ink chamber  213   a  is difficult to enter into the detection side ink chamber  213   b . Therefore, the malfunction caused by the attaching of bubble to the actuator  106  can be further prevented. Furthermore, a gap is provided between the lower end  212   cc  and the bottom wall  2   a  of the ink cartridge  180 F. A capillary force, which can hold ink, does not work on the gap provided between the lower end  212   cc  and the side wall  194   b.    
     FIG. 78  shows further another embodiment of the ink cartridge using the actuator  106 . An ink cartridge  180 G shown in  FIG. 78  has a partition wall  212   b  which is formed in L-shape. The partition wall  212   b  extends from a top wall  194   c . A lower end  212   bb  of the partition wall  212   b  is longer than the lower end  212   aa  of the partition wall  212   a  in the embodiment shown in  FIG. 72  to  FIG. 77 . A porous member  1005   f  is filled in the detection side ink chamber  213   b.    
   A porous member  1005   g , which is a bottom part of porous member  1005   f , is sandwiched and compressed by the lower end  212   bb  and the side wall  194   b . Therefore, the hole diameter of the porous member  1005   g  is smaller than the hole diameter of the porous member  1005   f . Thus, the hole diameter of the porous member decreases from the porous member  1005   f , which locates nearby the actuator  106 , to the porous member  1005   g  and further to porous member  1005   h . The hole diameter of the porous member  1005   f  thereby decreases step by step downward to the ink surface. Therefore, the ink, which once flows into the lower part of the porous member  1005   f  does not flow backward to the upside of the porous member  1005   f  by the capillary force. Furthermore, the porous member  1005   f  of the present embodiment prevents ink to attach to the actuator  106 , which is mounted on the top wall  194   c , by the waving of ink. Therefore, the malfunction of the actuator  106  to detect the ink end status as the ink exist status can be prevented. 
   Moreover, the bottom end  212   bb  is longer than the lower end  212   aa  of the partition wall  212   a  of the embodiments shown in  FIG. 72  to  FIG. 77 . Therefore, gas existed in the ventilation side ink chamber  213   a  is difficult to enter into the detection side ink chamber  213   b . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly caused by the attaching of bubble to the actuator  106  can be further prevented. Furthermore, a gap is provided between the lower end  212   bb  and the bottom wall  2   a . A capillary force, which can hold ink, does not work on the gap provided between the lower end  212   bb  and the bottom wall  2   a.    
     FIG. 79  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 H shown in  FIG. 79  has a first partition wall  212   d  which extends downward from the top face  194   c  of the ink container  194 . Furthermore, a second wall extends from the first partition wall  212   d  toward the side wall  194   b  substantially parallel to the ink surface. The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the first partition wall  212   d . Furthermore, the second partition wall  212   e  separates the detection side ink chamber into a first detection side ink chamber  213   c  and a second detection side ink chamber  213   d . A gap is provided between the bottom wall  2   a  and the lower end  212   dd  of the first partition wall  212   d . Furthermore, a gap is provided between the side wall  194   b  and the one end  212   ee  of the second partition wall  212   e . A concave part is provided on a part of top wall  194   c  to form a buffer  214   a  which accepts the bubble. Furthermore, porous member  1005   i  is filled inside the first detection side small ink chamber  213   c . One end  212   ee  of the second partition wall  212   e , which extends toward the side wall  194   b , extends until to the position where just under the buffer  214   b.    
   Therefore, first, the first partition wall  212   d  prevents the entering of bubble into the first detection side ink chamber  213   c . If the bubble enters into the detection side ink chamber  213   c  mistakenly, the bubble is absorbed by the porous member  1005   i . Furthermore, if the bubble reaches to the second partition wall  212   e , the bubble is introduced to the position which is just under the buffer  214   a  by the second partition wall  212   e . Therefore, the bubble is caught by the buffer  214   a . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly by the attaching of bubble to the actuator  106 , which is provided in the second detection side ink chamber  213   d , can be further prevented. 
     FIG. 80  shows further another embodiment of the ink cartridge  180 . An ink cartridge  180 I shown in  FIG. 80  has a partition wall  212   a  as same as the partition wall  212   a  of  FIG. 72 . The partition wall  212   a  extends downward from the top face  194   c  of the ink container  194 . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  212   a . A gap is provided between the bottom wall  1   a  and the partition wall  212   a . A porous member  1005   b  is provided inside the detection side ink chamber  213   b . Furthermore, a concave part is provided on a part of top wall  194   c  to form a buffer  214   b  which accepts the bubble. A tapered face  1040  is provided between the buffer  214   b  and the actuator  106 . 
   Therefore, first, the partition wall  212   a  prevents the entering of bubble into the detection side ink chamber  213   b . If the bubble enters into the detection side ink chamber  213   b  mistakenly, the bubble is absorbed by the porous member  1005   b . If the bubble reaches to the upper side of the detection side ink chamber  213   b , the bubble is directly caught by the buffer  214   a  or introduced to the buffer  214   b  along the tapered face  1040 . Therefore, the malfunction of the actuator  106  to detects the ink end wrongly by the attaching of bubble to the actuator  106  can be further prevented. The shape and size of the buffer can be other arbitrary shape and size. 
   Moreover, the second partition wall  212   e  in the embodiment shown in  FIG. 79  can be provided on the ink cartridge  1801  of the embodiment shown in  FIG. 80  such that the second partition wall  212   e  extends from the first partition wall  212   a  toward the side wall  214   b  in the direction parallel to the ink surface. In this case, one end  212   ee  of the second partition wall  212   e  is extended to the position just under the taper face  1040 . 
     FIG. 82  shows further another embodiment of the ink cartridge  180  using actuator  106 . An ink cartridge  180 K shown in  FIG. 82  has a protruding part  214   f , which protrudes inside the container  194 , on a part of the top wall  194   c . The actuator  106  is mounted on the bottom part of the protruding part  214   f . A partition wall  212   f  extends downward from the top face  194   c . A buffer  214   c  is provided for each of the position between the actuator  106  and the partition wall  212   a  and between the actuator  106  and the side wall  194   b . Therefore, the periphery of the actuator  106  is surrounded by the buffer  214   c . A porous member  1005   b  is provided inside the detection side ink chamber  213   b . By providing the actuator  106  on the protruding part  214   f , positioning for mounting the actuator  106  on the ink cartridge  180 J becomes easier when manufacturing the ink cartridge  180 J. 
     FIG. 82  shows further another embodiment of the ink cartridge  180  using actuator  106 . An ink cartridge  180 K shown in  FIG. 82  has a partition wall  212   a  extends downward from the top face  194   c . The container  194  is separated into a ventilation side ink chamber  213   a  and a detection side ink chamber  213   b  by the partition wall  2129 . Uneven part is provided on the top wall  194   c , and two actuators  106  are mounted on the protruding part which protrudes inside the detection side ink chamber  213   b . The concave part of the top wall  194   c  works as a buffer  214   c  which accepts bubble. Furthermore, a porous member  1005   b  is provided inside the detection side ink chamber  213   b . By providing two actuators  106  on the protruding part  214   f , detecting the ink consumption status mistakenly can be prevented. The number of the actuators  106  can be more than three. Moreover, as shown in  FIG. 81 , positioning for mounting the actuator  106  on the ink cartridge  180 K becomes easier when manufacturing the ink cartridge  180 K. The number of uneven part and the number of the actuator  106  can be further increased. 
     FIG. 83  shows further other embodiment of the ink cartridge  180  using actuator  106 . The ink cartridge  180 M shown in  FIG. 83  has a plurality of partition walls  212   f ,  212   g ,  212   h , and  212   i , each of which extends downward from the top face  194   c  of the ink container  194 . The partition wall  212   f  is first partition wall, and the partition walls  212   g ,  212   h , and  212   i  are the second partition walls. Because each of lower ends  212   ff ,  212   gg ,  212   hh , and  212   ii  of each of the partition walls  212   f ,  212   g ,  212   h , and  212   i  and the bottom wall  2   a  of the container  194  have a predetermined gap, the bottom part of the container  194  communicates with each other. The ink cartridge  180 M has a ventilation side ink chamber  213   a  and a plurality of detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i  separated by the each of plurality of partition walls  212   f ,  212   g ,  212   h  and  212   i . The bottom part of a plurality of the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i  communicate with each other. Each of the actuators  106   f ,  106   g ,  106   h , and  106   i  is mounted on the top face  194   c  of each of the plurality of the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i , respectively. Each of the actuators  106   f ,  106   g ,  106   h , and  106   i  is arranged on substantially center of the top face  194   c  of each of the plurality of the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i , respectively. 
   The volume of the ventilation side ink chamber  213   a , and the detection side small ink chamber  213   f ,  213   g ,  213   h , and  213   i  are gradually decreases as the distance from the airhole  128  increases to the inner side of the ink container  194 . Therefore, the volume of the ink chambers gradually decreases in the order from the ventilation side ink chamber  213   a , the detection side small ink chamber  213   f ,  213   g ,  213   h , and  213   i . Therefore, the interval of the mounting position of the actuator  106  is wider on the airhole  128  side and becomes narrower as the distance from the airhole increases to the inner side of the ink container  194 . 
   Furthermore, each of the porous members  1005   f ,  1005   g ,  1005   h  and  1005   i  are filled in the each of the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i . The each of the porous members  1005   f ,  1005   g ,  1005   h  and  1005   i  are filled from the detection side small ink chambers  213   f , which is near to the airhole  128 , to the detection side small ink chamber  213   i , which is far from the airhole  128 , sequentially. The porous members are designed such that the hole diameter increases in the order from the porous member  1005   f ,  1005   g ,  1005   h  and  1005   i . The porous members can be formed such that the affinity for ink decreases in the order from the porous member  1005   f ,  1005   g ,  1005   h  and  1005   i.    
   Because gas is introduced from the airhole  128 , ink is consumed from the ventilation side ink chamber  213   a  of the airhole  128  side to the detection side ink chamber  213   i . For example, the ink in the ventilation side ink chamber  213   a  which is nearest to the airhole  128  is consumed, and during the ink level of the ventilation side ink chamber  213   a  decreases, the other detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i  are filled with ink. When the ink level in the ventilation side ink chamber  213   a  reaches to the lower end  212   tt  of the partition wall  212   f , air enters into the detection side small ink chamber  213   f , and then the ink in the detection side small ink chamber  213   f  is beginning to be consumed. The ink level in the detection side small ink chamber  213   f  thereby begin to decrease. At this time, ink is filled in the detection side small ink chambers  213   g ,  213   h , and  213   i . In this way, ink is sequentially consumed from the ventilation side ink chamber  213   a  to the detection side small ink chamber  213   i.    
   Furthermore, the porous members are designed such that the hole diameter increases in the order from the porous members  1005   f ,  1005   g ,  1005   h  and  1005   i . Therefore, ink is consumed in the order from the detection side small ink chamber  213   f  which is relatively near to the airhole  128  to the detection side small ink chamber  213 I which is far from the airhole  128 , sequentially. Moreover, the porous members  1005   f ,  1005   g ,  1005   h  and  1005 I prevent ink to flow back from the detection side small ink chamber  213   f  to the detection side small ink chamber  213   i.    
   In the present embodiment, each of the actuators  106   f ,  106   g ,  106   h , and  106   i  is mounted on the top wall  194   c  of each of the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213 I with interval. Therefore, the actuators  106   f ,  106   g ,  106   h , and  106   i  can detect the decrease of the ink quantity step by step. Furthermore, the volume of the ink chambers decreases from the ventilation side ink chamber  213   a  to the detection side small ink chamber  213   i  gradually. Therefore, the time interval of detecting the decrease of the ink quantity gradually decreases. Therefore, the frequency of the ink quantity detection can be increased as the ink end is drawing near. 
   Furthermore, each of the volume of the detection side small ink chamber can be changed by changing the length of the partition wall as in the embodiment shown in  FIG. 87 . 
     FIG. 84  shows further other embodiment of the ink cartridge  180  using actuator  106 . In the ink cartridge  180 N shown in  FIG. 84 , porous members  1006   f ,  1006   g ,  1006   h  and  1006   i  are provided in the ink cartridge  180 N such that each porous members  1006   f ,  1006   g ,  1006   h  and  1006   i  closes the each of the communication port of the ventilation side ink chamber  213   a , the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i . Each of the ventilation side ink chamber  213   a , the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i  communicates each other through the porous members  1006   f ,  1006   g ,  1006   h  and  1006   i . Therefore, the porous members prevent the bubble, which is generated in the ink container  194 , to enter into the ventilation side ink chamber  213   a , the detection side small ink chambers  213   f ,  213   g ,  213   h , and  213   i . Therefore, even if the bubble generates in one of the detection side ink chambers, and one of the actuators  106   f ,  106   g ,  106   h , and  106   i  detects the ink end status mistakenly, the other actuators  106   f ,  106   g ,  106   h , and  106   i  do not detect the ink end status mistakenly. 
     FIG. 85  shows further other embodiment of the ink cartridge using the actuator  106 . The ink cartridge  220 A shown in  FIG. 85  has a first partition wall  222  provided such that it extends downward from the top wall of the ink cartridge  220 A. Because there is a predetermined space between the lower end of the first partition wall  222  and the bottom wall  3   a  of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the bottom wall  3   a  of the ink cartridge  220 A. A second partition wall  224  is formed such that the second partition wall  224  extends upward from the bottom wall  3   a  of the ink cartridge  220 A on the more ink supply port  230  side of the first partition wall  222 . Because there is a predetermined space between the upper end of the second partition wall  224  and the top wall  221  of the ink cartridge  220 A, ink can flows into the ink supply port  230  through the top wall  221  of the ink cartridge  220 A. 
   A ventilation side ink chamber  225   a  is formed relatively near to the airhole  233 . On the other hand, a detection side ink chamber  225   b  is formed relatively far from the airhole  233 . By the second partition wall  224 , the detection side ink chamber  225   b  and a detection side small ink chamber  227  are formed. The detection side small ink chamber  227  is formed between the first partition wall  222  and the second partition wall  224 . The detection side small ink chamber  227  is formed by providing a gap, which can generate the capillary phenomenon, between the first partition wall  222  and the second partition wall  224 . Therefore, the ink in the ventilation side ink chamber  225   a  is collected to the detection side small ink chamber  227  by the capillary force of the detection side small ink chamber  227 . Therefore, the detection side small ink chamber  227  can prevent that the air bubble to enter into the detection side ink chamber  225   b . Furthermore, the ink level in the detection side ink chamber  225   b  can decrease steadily and gradually. 
   Moreover, a porous member  1005   g  is provided inside the detection side ink chamber  225   b . The volume of the ventilation side ink chamber  225   a  is larger than the volume of the detection side ink chamber  225   b . Because the ventilation side ink chamber  225   a  is formed closer to the airhole  223  than the detection side small ink chamber  225   b , the ink in the detection side small ink chamber  225   b  is consumed after the ink in the ventilation side ink chamber  225   a  is consumed. Furthermore, the waving of ink inside the detection side small ink chamber  225   b  is prevented by providing the porous member  1005   g  inside the detection side small ink chamber  225   b . Moreover, the porous member  1005   g  prevents the bubble, which is entered from the ink supply port  230 , to attach to the actuator  106 . 
   Furthermore, the capillary force of the porous member  1005   g  is greater than the capillary force of the detection side small ink chamber  227 . The porous member  1005   g  thereby prevents ink to flow back from the ink supply port  230  to the ventilation side small ink chamber  225   a . The capillary force of the porous member  1005   g  can be increased by adjusting the hole diameter. Moreover, the capillary force of the porous member  1005   g  can be increased by compressing the porous member  1005   g.    
   A airhole  233  is provided on the top wall of the ink cartridge  220 A. Moreover, a check valve  228  is provided on the airhole  233  for preventing the leaking of ink from the airhole  233 . The leaking of ink outside the ink cartridge  220 A caused by the rolling of the ink cartridge  220 A can be prevented by the check valve  228 . Furthermore, the evaporation of ink from the airhole  233  of the ink cartridge  220 A can be prevented by providing the check valve  228  on the top face of the ink cartridge  220 A. If ink in the ink cartridge  220 A is consumed, and negative pressure inside the ink cartridge  220 A exceeds the pressure of the check valve  228 , the check valve  228  opens and introduces air into the ink cartridge  220 A. Then the check valve  228  closes to accelerate the drainage of ink from the ink cartridge  220 A. 
   Here, a piezoelectric device as an embodiment of a liquid censor will be explained. The piezoelectric device, or actuator, detects a state of the liquid inside a liquid container by utilizing vibration phenomena. The state of the liquid includes whether or not the liquid in the liquid container is empty, amount of the liquid, level of the liquid, types of the liquid and combination of liquids. Several specific methods realizing for detection of the state of the liquid inside the liquid container utilizing vibration phenomena are considered. For example, a method is considered in which the medium and the change of its state inside the liquid container are detected in such a manner that an elastic wave generating device generates an elastic wave inside the liquid container, and then the reflected wave which is thus reflected by the liquid surface or a wall disposed counter thereto is captured. There is another method in which a change of acoustic impedance is detected by vibrating characteristics of a vibrating object. As a method utilizing the change of the acoustic impedance, a vibrating portion of a piezoelectric device or an actuator having a piezoelectric element therein is vibrated. Thereafter, a resonant frequency or an amplitude of the back electromotive force waveform is detected by measuring the back electromotive force which is caused by residual vibration which remains in the vibrating portion, so as to detect the change of the acoustic impedance. As another method utilizing the change of the acoustic impedance, the impedance characteristic or admittance characteristic of the liquid is measured by a measuring apparatus such as an impedance analyzer and a transmission circuit, so that the change of a current value or a voltage value, or the change of the current value or voltage value due to the frequency caused by the vibration given to the liquid is measured. In the present embodiment, the actuator  106  can detect the liquid status inside the liquid container by any method mentioned above. 
     FIG. 86  shows further other embodiment of the ink cartridge  180 .  FIG. 86  shows a cross section of an ink cartridge  180 P. The semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610  in the ink cartridge  180 P. 
   A different-type O-ring  614  is mounted on the side wall  194   b  such that the different-type O-ring  614  surrounds the actuator  106 . A plurality of caulking part  616  is formed on the side wall  194   b  to couple the circuit board  610  with the container  194 . By coupling the circuit board  610  with the container  194  using the caulking part  616  and pushing the different-type O-ring  614  to the circuit board  610 , the vibrating region of the actuator  106  can contacts with ink, and at the same time, the inside of the ink cartridge is sealed from outside of the ink cartridge. 
   A terminals  612  are formed on the semiconductor memory device  7  and around the semiconductor memory device  7 . The terminal  612  transfer the signal between the semiconductor memory device  7  and outside the ink jet recording apparatus. The semiconductor memory device  7  can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610 , the mounting process can be finished at one time during mounting the semiconductor memory device  7  and the actuator  106  on the ink cartridge  180 P. Moreover, the working process during the manufacturing of the ink cartridge  180 C and the recycling of the ink cartridge  180 P can be simplified. Furthermore, the manufacturing cost of the ink cartridge  180 P can be reduced because the numbers of the parts can be reduced. 
   The actuator  106  detects the ink consumption status inside the container  194 . The semiconductor memory device  7  stores the information of ink such as residual quantity of ink detected by the actuator  106 . That is, the semiconductor memory device  7  stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator  106  when detecting the ink consumption status. The semiconductor memory device  7  previously stores the resonant frequency of when ink inside the container  194  is full, that is, when ink is filled in the container  194  sufficiently, or when ink in the container  194  is end, that is, ink in the container  194  is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container  194  is full status or end status can be stored when the ink container is mounted on the ink jet recording apparatus for the first time. Moreover, the resonant frequency when the ink inside the container  194  is full status or end status can be stored during the manufacturing of the container  194 . Because the unevenness of the detection of the residual quantity of ink can be compensated by storing the resonant frequency when the ink inside the container  194  is full status or end status in the semiconductor memory device  7  previously and reading out the data of the resonant frequency at the ink jet recording apparatus side, it can be accurately detected that the residual quantity of ink is decreased to the reference value. 
     FIG. 87  shows further other embodiment of the ink cartridge  180 . The ink cartridge  180 Q shown in  FIG. 87  has a plurality of partition walls  212   p ,  212   q , and  212   r . The partition walls  212   p ,  212   q , and  212   r  separates the ink container  194  into the ventilation side ink chamber  213   a  and the detection side small ink chamber  213   p ,  213   q , and  213   r . The partition wall  212   p  is the first partition wall, and the partition walls  212   q  and  212   r  are the second partition walls. Each of porous members  1005   p ,  1005   q , and  1005   r  are provided in the each of the detection side small ink chamber  213   p ,  213   q , and  213   r . Furthermore, each of partition walls  212   p ,  212   q , and  212   r  are provided on the top wall  194   c  with substantially equal intervals. Furthermore, each of the partition walls  212   p ,  212   q , and  212   r  extends from the top wall  194   c  toward the bottom wall  2   a . Each of the partition walls  212   p ,  212   q , and  212   r  have different length. Moreover, the length of the partition walls  212   p ,  212   q , and  212   r  increases in the order of the partition wall  212   p ,  212   q , and  212   r . Therefore, even the interval between the each of the partition walls  212   p ,  212   q , and  212   r  is different, the volume of the each of the detection side small ink chambers are different with each other. 
   Because the length of each of the partition walls  212   p ,  212   q , and  212   r  increases with the increase of the distance from the airhole  128 , gas is most difficult to enter into the detection side small ink chamber  213   r  which is farthest from the airhole  128 . Therefore, the actuator  106   r  can detect the ink existence most accurately among the actuators  106   p ,  106   q , and  106   r  which is mounted on the each of the detection side small ink chamber  213   p ,  213   q , and  213   r.    
     FIG. 88  shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator  106 . In the present embodiment, the ink cartridge  180 A shown in  FIG. 72  is used. However, the ink cartridge in any of the ink cartridge shown in  FIG. 73  to  FIG. 84  also can be used. Furthermore, the ink cartridge of the other form also can be used. A plurality of ink cartridges  180 A is mounted on the ink jet recording apparatus which has a plurality of ink introducing members  182  and a holder  184  each corresponding to the each of ink cartridge  180 , respectively. Each of the plurality of ink cartridges  180 A contains different types of ink, for example, different color of ink. The actuator  106 , which detects at least acoustic impedance, is mounted on the each of top wall of the plurality of ink cartridge  180 A. The actuator  106 , a partition wall  212   a , and a porous member  1005   b  are provided for each top wall of the plurality of ink cartridge  180 A. The residual quantity of ink in the ink cartridge  180  can be detected by mounting the actuator  106  on the ink cartridge  180 . The partition wall  212   a  prevents the waving and bubbling of ink. 
     FIG. 89  shows a detail around the head member of the ink jet recording apparatus. In the present embodiment, the ink cartridge  180 A shown in  FIG. 72  is used. However, the ink cartridge in any of the ink cartridge shown in  FIG. 73  to  FIG. 84  also can be used. Furthermore, the ink cartridge of the other form also can be used. The ink jet recording apparatus has an ink introducing member  182 , a holder  184 , a head plate  186 , and a nozzle plate  188 . A plurality of nozzle  190 , which jet out ink, is formed on the nozzle plate  188 . The ink introducing member  182  has an air supply hole  181  and an ink introducing inlet  183 . The air supply hole  181  supplies air to the ink cartridge  180 . The ink introducing inlet  183  introduces ink from the ink cartridge  180 A. The ink cartridge  180 A has an air introducing inlet  185  and an ink supply port  187 . The air introducing inlet  185  introduces air from the air supply hole  181  of the ink introducing member  182 . The ink supply port  187  supplies ink to the ink introducing inlet  183  of the ink introducing member  182 . By introducing air from the ink introducing member  182  to the ink cartridge  180 , the ink cartridge  180  accelerates the supply of ink from the ink cartridge  180 A to the ink introducing member  182 . The holder  184  communicates ink, which is supplied from the ink cartridge  180 A through the ink introducing member  182 , to the head plate  186 . Ink is supplied to the head from the ink cartridge  180 A through the ink introducing member  182  and discharged to the recording medium from nozzle. In this way, the ink jet recording apparatus performs the printing on the recording medium. 
     FIG. 90  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink. In the ink cartridge shown in  FIG. 90 , the detection method implemented is based on a method, among methods described above, in which the position of the liquid surface in the liquid container and whether or not the liquid is empty are detected by receiving the reflected wave of the elastic wave. As a means for generating and receiving the elastic wave, an elastic wave generating device  3  is utilized. An ink supply port  2  which comes in contact with an ink supply needle of the recording apparatus in a sealed manner is provided in a container  1  which houses the ink. In an outside portion of a bottom face  1   a  of the container  1 , the elastic wave generating device  3  is mounted such that the elastic wave can be communicated, via the container, to the ink inside the container. In order that at a stage at which the ink K is almost used up, i.e. at the time when the ink becomes an ink-end state, the transfer of the elastic wave can change from the liquid to the gas, the elastic wave generating device  3  is provided in a slightly upward position from the ink supply port  2 . Moreover, an elastic wave receiving means may be separately provided instead, so that the elastic wave generating device  3  is used as an elastic wave generating device only. 
   A packing ring  4  and a valve body  6  are provided in the ink supply port  2 . Referring to  FIG. 91 , the packing ring  4  is engaged with the ink supply needle  32  communicating with a recording head  31 , in a fluid-tight manner. The valve body  6  is constantly and elastically contacted against the packing ring  4  by way of a spring  5 . When the ink supply needle  32  is inserted, the valve body  6  is pressed by the ink supply needle  32  so as to open an ink passage, so that ink inside the container  1  is supplied to the recording head  31  via the ink supply port  2  and the ink supply needle  32 . On an upper wall of the container  1 , there is mounted a semiconductor memory means  7  which stores data on ink inside the ink cartridge. 
   Furthermore, a porous member  1050  is provided inside the container  1 . A gap is provided between the porous member  1050  and the elastic wave generating device  3  to form an ink layer. By providing the porous member  1050  inside the container  1 , the porous member  1050  prevents the waving or bubbling of ink inside the container  1  when the ink cartridge moves together with the recording head by the scanning operation during the printing process. Therefore, the bubble and wave of ink is difficult to generate around the elastic wave generating device  3 , the elastic wave generating device  3  can accurately detect the ink consumption status. 
   Furthermore, the hole diameter of porous member  1050  is set such that the porous member  1050  does not absorbs ink existed in the ink layer  1060  when the ink surface reaches to the ink layer  1060  by the consumption of ink inside the container  1 . In other words, the porous member  1050  is designed such that the capillary force works in the porous member  1050  does not hold ink in the container  1 . Therefore, ink does not remain in the porous member  1050  by its own weight and remains in the ink layer  1060  when the ink inside the container  1  is in an ink near end status. 
   An airhole, not shown in the figure, is provided on the container  1 . The airhole is provided on the upper side of the ink surface to communicate with outside of container  1 . Air is introduced inside the container  1  by the airhole, and ink flows downward by its own weight with advance of ink consumption. The residual ink thereby stays in the ink layer  1060 . Because the porous member  1050  is provided inside the container  1 , the elastic wave generating device  3  can detect the ink quantity only when the ink status is near to the ink end if the width of the ink layer is small. However, ink does not wave by providing the porous member  1050  in the container  1 . Therefore, the elastic wave generating device  3  can detect the ink surface accurately when the ink surface inside the container  1  reaches to the lower end of the porous member  1050 , and ink surface exists within the ink layer  1060 . 
   Moreover, the width of the gap between the porous member  1050  and the elastic wave generating device  3  is not limited. To suppress the bubbling of ink as much as possible, the width of ink layer  1060  is reduced by providing the porous member  1050  on lower side of the container  1 . If the width of the ink layer  1060  is small, the elastic wave generating device  3  can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container  1 . Therefore, the elastic wave generating device  3  can accurately detect the ink quantity and existence of ink when the ink consumption status is near to the ink end status. Therefore, the porous member  1050  is preferably located nearby the elastic wave generating device  3  without limiting the width of gap between the porous member  1051  and elastic wave generating device  3 . Moreover, even the bubble of ink generates, because the bubble of ink is absorbed in the porous member  1050 , the bubble does not stays around the elastic wave generating device  3 . The porous member  1050  thereby prevents the elastic wave generating device  3  to detect the ink consumption status mistakenly. 
     FIG. 91  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 90 . A carriage  30  capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit  33 , while the recording head  31  is provided in a lower face of the subtank unit  33 . Moreover, the ink supply needle  32  is provided in an ink cartridge mounting face side of the subtank unit  33 . 
   While the recording apparatus is operating, a drive signal is supplied to the elastic wave generating device  3  at a detection timing which is set in advance, for example, at a certain period of time. The elastic wave generated by the elastic wave generating device  3  is transferred to the ink by propagating through the bottom face  1   a  of the container  1  so as to be propagated to the ink. 
   By adhering the elastic wave generating device  3  to the container  1 , since a process of embedding electrodes for use in detecting the liquid surface is unnecessary in the course of forming the container  1 , an injection molding process can be simplified and the leakage of the liquid from a place in which the electrodes are supposedly embedded can be avoided, thus improving the reliability of the ink cartridge. 
   Furthermore, a porous member  1050  is provided inside the container  1 . By providing the porous member  1050  inside the container  1 , the porous member  1050  prevents the waving or bubbling of ink inside the container  1  when the ink cartridge moves together with the recording head by the scanning operation during the printing process. Because the bubble and wave of ink is difficult to generate around the elastic wave generating device  3 , the elastic wave generating device  3  can accurately detect the ink consumption status. 
     FIG. 92  is a detailed cross sectional view of a subtank unit  33 . The subtank unit  33  comprises the ink supply needle  32 , the ink chamber  34 , a flexible valve  36  and a filter  37 . In the ink chamber  34 , the ink is housed which is supplied from the ink cartridge via ink supply needle  32 . The flexible valve  36  is so designed that the flexible valve  36  is opened and closed by means of the pressure difference between the ink chamber  34  and the ink supply passage  35 . The subtank unit  33  is so constructed that the ink supply passage  35  is communicated with the recording head  31  so that the ink can be supplied up to the recording head  31 . 
   Referring to  FIG. 91 , when the ink supply port  2  of the container  1  is inserted through the ink supply needle  32  of the subtank unit  33 , the valve body  6  recedes against the spring  5 , so that an ink passage is formed and the ink inside the container  1  flows into the ink chamber  34 . At a stage where the ink chamber  34  is filled with ink, a negative pressure is applied to a nozzle opening of the recording head  31  so as to fill the recording head with ink. Thereafter, the recording operation is performed. 
   When the ink is consumed in the recording head  31  by the recording operation, a pressure in the downstream of the flexible valve  36  decreases. Then, the flexible valve  36  is positioned away from a valve body  38  so as to become opened. When the flexible valve  36  is opened, the ink in the ink chamber  34  flows into the recording head  31  through the ink passage  35 . Accompanied by the ink which has flowed into the recording head  31 , the ink in the container  1  flows into the subtank unit  33  via the ink supply needle  32 . 
   According to the embodiment shown in  FIG. 91  and  FIG. 92 , the elastic wave generating device  3  and the porous member  1050  are provided also in the subtank unit  33 . The porous member  1050  is provided nearby the elastic wave generating device  3 . A gap is provided to form a ink layer  1060  between the elastic wave generating device  3  and the porous member  1050 . 
   The elastic wave generating device  3  detects the ink quantity or existence of ink inside the subtank unit  33 . In case of the present embodiment, because the porous member  1050  is provided inside the subtank unit  33 , if the width of the ink layer  1060  becomes small, the elastic wave generating device  3  can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container  1  because the porous member  1050  is provided inside the subtank unit  33 . Therefore, the elastic wave generating device  3  can accurately detect the ink surface when the ink surface inside the subtank unit  33  reaches to the lower end of the porous member  1050  and exits between the ink layer  1060 . Moreover, the elastic wave generating device  3  can detect the ink quantity and existence of ink inside the subtank unit  33  accurately. 
   Moreover, because the elastic wave generating device  3  is provided inside the subtank unit  33 , the elastic wave generating device  3  can detect the ink quantity and the existence of ink inside the subtank unit  33  even when the ink inside the ink cartridge  180  is used up. Therefore, the ink jet recording apparatus can judge whether the printing process can be continued or not. 
   The elastic wave generating device  3  and the porous member  1050  are provided inside the container  1  of the ink cartridge in the embodiment shown in  FIG. 91 . Moreover, as shown in  FIG. 91  and  FIG. 92 , the elastic wave generating device  3  and the porous member  1050  are also provided inside the subtank unit  33 . Therefore, the elastic wave generating device  3  and the porous member  1050  are provided on both of the ink cartridge shown in  FIG. 91  and the subtank unit  33  shown in  FIG. 92 . However, the elastic wave generating device  3  and the porous member  1050  can be provided to only one of the ink cartridge shown in  FIG. 91  or the subtank unit  33  shown in  FIG. 92 . 
   According to the embodiment shown in  FIG. 93 , if the ink absorbing member  74  and  75  expose from the ink by consumption of ink inside the container  1 , ink contained in the ink absorbing member  74  and  75 , which is made from a porous material, flows out by the own weight and is supplied to the recording head  31 . If ink is used up, the ink absorbing member  74  and  75  absorbs the ink remained in the through hole  1   c , the ink is thereby drained from the concave part of the through hole  1   c . Therefore, the condition of the reflective wave of the elastic wave generated by the elastic wave generating device  70  at the ink end status changes, and thus the timing of ink end status can be further accurately detected. Furthermore, the ink absorbing member  74  and  75  are designed such that the capillary force works in the ink absorbing member  74  and  75  is equal to the capillary force which can hold ink or greater than the capillary force which can hold ink. The ink absorbing member  74  and  75  thereby absorb ink remained in the through hole  1   c.    
     FIGS. 94(I)-94(V)  show manufacturing methods of the elastic wave generating device  3 ,  15 ,  16  and  17 . A base plate  20  is formed by material such as the burning-endurable ceramic. Referring to  FIG. 94(I) , first of all, a conductive material layer  21  which becomes an electrode at one side is formed on the base plate  20 . Next, referring to FIG.  94 (II), a green sheet  22  serving as piezoelectric material is placed on the conductive material layer  21 . Next, referring to FIG.  94 (III), the green sheet  22  is formed in a predetermined shape by a press processing or the like and is made into the form of a vibrator, and is air-dried. Thereafter, the burning is performed on the green sheet  22  at a burning temperature of, for example, 1200° C. Next, referring to FIG.  94 (IV), a conductive material layer  23  serving as other electrode is formed on the surface of the green sheet  22  so as to be polarized in a capable of flexural-oscillation manner. Finally, referring to  FIG. 94(V) , the base plate  20  is cut along each element. By fixing the base plate  20  in a predetermined face of the container  1  by use of adhesive or the like, the elastic wave generating device  3  can be fixed on the predetermined face of the container and the ink cartridge is completed which has a built-in function which detects the ink remaining amount. 
     FIG. 95  shows another embodiment of the elastic wave generating device  3  shown in  FIG. 94 . In the embodiment shown in  FIG. 94 , the conductive material layer  21  is used as a connecting electrode. On the other hand, in the embodiment shown in  FIG. 95 , connecting terminals  21   a  and  23   a  are formed by a solder in an upper position than the surface of the piezoelectric material layer comprised of the green sheet  22 . By the provision of the connecting terminals  21   a  and  23   a , the elastic wave generating device  3  can be directly mounted to the circuit board, so that inefficient connection such as one by lead wires can be avoided. 
   Now, the elastic wave is a type of waves which can propagate through gas, liquid and solid as medium. Thus, the wavelength, amplitude, phase, frequency, propagating direction and propagating velocity of the elastic wave change based on the change of medium in question. On the other hand, the state and characteristic of the reflected wave of the elastic wave change according to the change of the medium. Thus, by utilizing the reflected wave which changes based on the change of the medium through which the elastic wave propagates, the state of the medium can be observed. In a case where the state of the liquid inside the liquid container is to be detected by this method, an elastic wave transmitter-receiver will be used for example. Let us explain this by referring to embodiments shown in  FIGS. 90-91 . First, the transmitter-receiver gives out the elastic wave to the medium, for example, the liquid or the liquid container. Then, the elastic wave propagates through the medium and arrives at the surface of the liquid. Since a boundary is formed between the liquid and the gas on the liquid surface, the reflected wave is returned to the transmitter-receiver. The transmitter-receiver receives the reflected wave. A distance between the liquid surface and a transmitter or receiver can be measured based on an overall traveled time of the reflected wave, or a damping factor of the amplitudes of the elastic wave generated by the transmitter and the reflected wave reflected on the liquid surface, and soon. Utilizing these, the state of the liquid inside the liquid container can be detected. The elastic wave generating device  3  may be used as a single unit of the transmitter-receiver in the method utilizing the reflected wave based on the change of the medium through which the elastic wave propagates, or a separately provided receiver may be mounted thereto. 
   As described above, in the elastic wave, generated by the elastic wave generating device  3 , propagating through the ink liquid, the traveling time of the reflected wave occurring on the ink liquid surface to arrive at the elastic wave generating device  3  varies depending on density of the ink liquid and the liquid level. Thus, if the composition of ink is fixed, the traveling time of the reflected wave which occurred in the ink liquid surface varies depending on the ink amount. Therefore, the ink amount can be detected by detecting the time period during which the elastic wave generating device  3  generates the elastic wave and then the wave reflected from the ink surface arrives at the elastic wave generating device  3 . Moreover, the elastic wave vibrates particles contained in the ink. Thus, in a case of using pigment-like ink which uses pigment as a coloring agent, the elastic wave contributes to prevent precipitation of the pigment or the like. 
   By providing the elastic wave generating device  3  in the container  1 , when the ink of the ink cartridge approaches (decreases to) an ink-end state and the elastic wave generating device  3  can no longer receive the reflected wave, it is judged as an ink-near-end and thus can give indication to replace the cartridge. 
     FIG. 96  shows an ink cartridge according to another embodiment of the present invention. Plural elastic wave generating device  41 - 44  are provided on the side wall of the container  1 , spaced at a variable interval from one another in the vertical direction. In the ink cartridge shown in  FIG. 96 , whether or not the ink is present at mounting levels of respective elastic wave generating device  41 - 44  can be detected by whether or not the ink is present at respective positions of the elastic wave generating device  41 - 44 . For example, suppose that the liquid level of ink is at a point between the elastic wave generating device  44  and  43 . Then, the elastic wave generating device  44  detects and judges that the ink is empty while the elastic wave generating device  41 ,  42  and  43  detect and judge respectively that the ink is present. Thus, it can be known that the liquid level of ink lies in a level between the elastic wave generating device  44  and  43 . Thus, provision of the plural elastic wave generating device  41 - 44  makes possible to detect the ink remaining amount in a step-by-step manner. 
     FIG. 97  and  FIG. 98  show ink cartridges according to still another embodiments of the present invention. In an embodiment shown in  FIG. 97 , an elastic wave generating device  65  is mounted in a bottom face  1   a  formed a slope in the vertical direction. In an embodiment shown in  FIG. 98 , an elastic wave generating device  66  of an elongated shape in the vertical direction is provided in the vicinity of the bottom face of a side wall  1   b.    
   According to the embodiments shown in  FIG. 97  and  FIG. 98 , when part of the elastic wave generating device  65  and  66  is exposed from the liquid surface, the traveled time of the reflected wave and the acoustic impedance of the elastic waves generated by the elastic wave generating device  65  continuously change corresponding to the change (Δh1, Δh2) of the liquid surface. Thus, the process from the ink-near-end state to the ink-end state of ink remaining amount can be accurately detected by detecting the degree of change in the traveled time of the reflected wave or the acoustic impedance of the elastic waves. 
   Furthermore, a porous member  1050  is provided inside the container  1 . The porous member  1050  prevents the waving and bubbling of ink inside the container  1 . The porous member  1050  thereby prevents the elastic wave generating device  65  and  66  to detects the ink existence mistakenly. 
   In the embodiment shown in  FIG. 97 , the porous member  1050  is provided in the container  1  such that the slope of the bottom face  1055  of the porous member  1050  is parallel to the slope of the elastic wave generating device  65 . A gap is provided between the bottom face  1055  and the elastic wave generating device  65  and forms a ink layer  1060 . Therefore, as the embodiment shown in  FIG. 90 , when the ink surface in the container  1  reaches to the lower end of the porous member  1050  and exists within the ink layer  1060 , the elastic wave generating device  3  can detect the ink surface accurately. 
   In the embodiment shown in  FIG. 98 , one side face of the porous member, not shown in the figure, is provided in the container  1  such that the one side face is parallel to the elastic wave generating device  66 . A gap is provided between the one side face and the side wall  1   a . In the present embodiment, when ink is filled inside the container  1  and gap between the one side face of the porous member and the side wall  1   b , the reflective wave of the elastic wave generated by the elastic wave generating device  66  does not change. On the other hand, if ink inside the container  1  is consumed, and the gap between the one side face of the porous member and the side wall  1   b  arises, the reflective wave of the elastic wave generated by the elastic wave generating device  66  gradually changes. Therefore, the elastic wave generating device  66  can detect the ink consumption status when the ink surface exists within the region of the length Δh2 of the elastic wave generating device  66 . The length of the elastic wave generating device  66  is not limited. 
   Though in the above embodiments a flexural oscillating type piezoelectric vibrator is used so as to suppress the increase of the cartridge size, a vertically vibrating type piezoelectric vibrator may also be used. In the above embodiments, the elastic wave is transmitted and received by a same elastic wave generating device. In still another embodiment, the elastic wave generating device may be provided separately as one for use in transmitting the elastic wave and other for receiving the elastic wave, so as to detect the ink remaining amount. 
     FIG. 99  shows an ink cartridge according to still another embodiment of the present invention. Plural elastic wave generating device  65   a ,  65   b  and  65   c  on the bottom face  1   a  formed a slope in the vertical direction spaced at an interval are provided in the container  1 . 
   Furthermore, a porous member  1050  is provided inside the container  1 . A gap is provided between the porous member  1050  and the elastic wave generating device  65   a ,  65   b , and  65   c  to form an ink layer  1060 . By providing the porous member  1050  inside the container  1 , the porous member  1050  prevents the waving or bubbling of ink inside the container  1  when the ink cartridge moves together with the recording head by the scanning operation during the printing process. Therefore, the bubble of ink is difficult to generate around the elastic wave generating device  65   z ,  65   b , and  65   c . Furthermore, even if the bubble of ink generates, because the porous member  1050  absorbs the bubble of ink, the bubble does not stay around the elastic wave generating device  65   a ,  65   b , and  65   c . The elastic wave generating device  65   a ,  65   b , and  65   c  can thereby accurately detect the ink consumption status. 
   The width of the ink layer  1060  is not limited as the embodiment t shown in  FIG. 97 . 
   According to the present embodiment, the arrival time (traveled time) of the reflected waves of the elastic waves to the respective elastic wave generating device  65   a ,  65   b  and  65   c  in the respective mounting positions of the elastic wave generating device  65   a ,  65   b  and  65   c  differs depending on whether or not the ink is present in the respective positions of the plural elastic wave generating device  65   a ,  65   b  and  65   c . Thus, whether or not the ink is present in the respective mounted position levels of the elastic wave generating device  65   a ,  65   b  and  65   c  can be detected by scanning each elastic generating means ( 65   a ,  65   b  and  65   c ) and by detecting the traveled time of the reflected wave of the elastic wave in the elastic wave generating device  65   a ,  65   b  and  65   c . Hence, the ink remaining amount can be detected in a step-by-step manner. For example, suppose that the liquid level of ink is at a point between the elastic wave generating device  65   b  and  65   c . Then, the elastic wave generating device  65   c  detects and judges that the ink is empty while the elastic wave generating device  65   a  and  65   b  detect and judge respectively that the ink is present. By overall evaluating these results, it becomes known that the liquid level of ink lies in a level between the elastic wave generating device  65   b  and  65   c.    
     FIGS. 100  and Fi.  101  show cross sections of the ink-jet recording apparatus according to still another embodiment of the present invention. 
     FIG. 100  shows a cross section of the ink-jet recording apparatus alone. 
     FIG. 101  is a cross section of the ink-jet recording apparatus to which the ink cartridge  272  is mounted. A carriage  250  capable of reciprocating in the direction of the width of the ink-jet recording paper includes a recording head  252  in a lower face thereof. The carriage  250  includes a subtank unit  256  in an upper face of the recording head  252 . The subtank unit  256  has a similar structure to that shown in  FIG. 92 . The subtank unit  256  has an ink supply needle  254  facing an ink cartridge  272  mounting side. In the carriage  250 , there is provided a convex part  258  in a manner such that the convex part  258  is disposed counter to a bottom portion of the ink cartridge  272  and in an area where the ink cartridge  272  is to be mounted there above. The convex part  258  includes an elastic wave generating device  260  such as the piezoelectric vibrator. 
     FIGS. 102  show an embodiment of the ink cartridge suitable for the recording apparatus shown in  FIGS. 100 . 
     FIG. 102  shows an embodiment of the ink cartridge for use with a single color, for instance, the black color. The ink cartridge  272  according to the present embodiment, comprises a container which houses ink and an ink supply port  276  which comes in contact with an ink supply needle  254  of the recording apparatus in a sealed manner. In the container  274 , there is provided the concave part  278 , positioned in a bottom face  274   a , which is to be engaged with the convex part  258  shown in  FIG. 101 . The concave part  278  houses ultrasound transferring material such as gelated material  280 . 
   The ink supply port  276  includes a packing ring  282 , a valve body  286  and a spring  284 . The packing ring  282  is engaged with the ink supply needle  254  in a fluid-tight manner. The valve body  286  is constantly and elastically contacted against the packing ring  282  by way of the spring  284 . When the ink supply needle  254  is inserted to the ink supply port  276 , the valve body  286  is pressed by the ink supply needle  254  so as to open an ink passage. On an upper wall of the container  274 , there is mounted a semiconductor memory means  288  which stores data on ink inside the ink cartridge and so on. 
   A porous member  1050  is provided inside the container  274 . A gap is provided between the porous member  1050  and the gelated material  280  to form an ink layer  1060 . By providing the porous member  1050  inside the container  274 , the porous member  1050  prevents the waving or bubbling of ink inside the container  274 . Therefore, the elastic wave generating device  260  can accurately detect the ink consumption status as shown in  FIG. 90 . 
   As in the embodiment shown in  FIG. 90 , the present embodiment of the elastic wave generating device  260  can accurately detect the ink surface when the ink surface inside the container  274  reaches to the lower end of the porous member  1050  and exists within the ink layer  1060 . The width of the gap between the porous member  1050  and the elastic wave generating device  260  is not limited. Preferably, the porous member  1050  is provided vicinity of the elastic wave generating device  260 . 
   Referring to  FIG. 101 , when the ink supply port  276  of the ink cartridge  272  is inserted through the ink supply needle  254  of the subtank unit  256 , the valve body  286  recedes against the spring  284 , so that an ink passage is formed and the ink inside the ink cartridge  272  flows into the ink chamber  262 . At a stage where the ink chamber  262  is filled with ink, a negative pressure is applied to a nozzle opening of the recording head  252  so as to fill the recording head with ink. Thereafter, the recording operation is performed. When the ink is consumed in the recording head  252  by the recording operation, a pressure in the downstream of a flexible valve  266  decreases. Then, the flexible valve  266  is positioned away from a valve body  270  so as to become opened. When the flexible valve  36  is opened, the ink in the ink chamber  262  flows into the recording head  252  through the ink passage  35 . Accompanied by the ink which has flowed into the recording head  252 , the ink in the ink cartridge  272  flows into the subtank unit  256 . 
   While the recording apparatus is operating, a drive signal is supplied to the elastic wave generating device  260  at a detection timing which is set in advance, for example, at a certain period of time. The elastic wave generated by the elastic wave generating device  260  is radiated from the convex part  258  and is transferred to the ink inside the ink cartridge  272  by propagating through the gelated material  280  in the bottom face  274   a  of the ink cartridge  272 . Though the elastic wave generating device  260  is provided in the carriage  250  in  FIGS. 101 , the elastic wave generating device  260  may be provided inside the subtank unit  256 . 
   Since the elastic wave generated by the elastic wave generating device  260  propagates through the ink liquid, the traveling time of the reflected wave occurring on the ink liquid surface to arrive at the elastic wave generating device  260  varies depending on density of the ink liquid and the liquid level. Thus, if the composition of ink is fixed, the traveling time of the reflected wave which occurred in the ink liquid surface varies depending on the ink amount. Therefore, the ink amount can be detected by detecting the time duration during which the reflected wave arrives at the elastic wave generating device  260  from the ink liquid surface when the ink liquid surface is excited by the elastic wave generating device  260 . Moreover, the elastic wave generated by the elastic wave generating device  260  vibrates particles contained in the ink. Thus, in a case of using pigment-like ink which uses pigment as a coloring agent, the elastic wave contributes to prevent precipitation of the pigment or the like. 
   After the printing operation and maintenance operation or the like and when the ink of the ink cartridge approaches (decreases to) an ink-end state and the elastic wave generating device  260  can no longer receive the reflected wave even after the elastic wave generating device sends out the elastic wave, it is judged that the ink is in an ink-near-end state and thus this judgment can give indication to replace the cartridge anew. Moreover, when the ink cartridge  272  is not mounted properly to the carriage  250 , the shape of the elastic wave from the elastic generating means  260  changes in an extreme manner. Utilizing this, warning can be given to a user in the event that the extreme change in the elastic wave is detected, so as to prompt the user to check on the ink cartridge  272 . 
   The traveling time of the reflected wave of the elastic wave generated by the elastic wave generating device  260  is affected by the density of ink housed in the container  274 . Since the density of ink may differ by the type of ink used, data on the types of ink are stored in a semiconductor memory means  288 , so that a detection sequence can be set based on the data and thus the ink remaining amount can be further precisely detected. 
     FIG. 103  shows an ink cartridge  272  according to still another embodiment of the present invention. In the ink cartridge  272  shown in  FIG. 103 , the bottom face  274   a  is formed a slope in the vertical direction. 
   In the ink cartridge  272  shown in  FIG. 103 , when the ink remaining amount is becoming low and part of a radiating area of the elastic wave generating device  260  is exposed from the liquid surface, the traveled time of the reflected wave of the elastic waves generated by the elastic wave generating device  260  continuously changes corresponding to the change Δh1 of the liquid surface. The Δh1 denotes change of the height of the bottom face  274   a  in both ends of the gelated material  280 . Thus, the process from the ink-near-end state to the ink-end state of ink remaining amount can be accurately detected by detecting the degree of change in the traveled time of the reflected wave of the elastic wave generating device  260 . 
   Furthermore, a porous member  1050  is provided inside the container  274 . The porous member  1050  prevents the waving or bubbling of ink inside the container  274 . Therefore, the elastic wave generating device  260  can accurately detect the ink consumption status. 
   The porous member  1050  is provided in the container  274  such that the slope of the bottom face  1055  of the porous member  1050  is parallel to the slope of the bottom face of the container  274 . A gap is provided between the bottom face  1055  and the elastic wave generating device  260  and forms a ink layer  1060 . 
   When ink is filled inside the container  274  and ink layer  1060 , the reflective wave of the elastic wave generated by the elastic wave generating device  260  does not change. On the other hand, if ink inside the container  274  is consumed, gap arises in the ink layer  1060  instead of ink. With the arising of the gap in the ink layer  1060 , the reflective wave of the elastic wave generated by the elastic wave generating device  260  gradually changes. Therefore, the elastic wave generating device  260  can detect the ink quantity when the ink status in the container  274  is near to ink end status. The width of the ink layer  1060  is not limited as the embodiment shown in  FIG. 97 . 
     FIG. 104  shows an ink cartridge  272  and an ink-jet recording apparatus according to still another embodiment of the present invention. The ink-jet recording apparatus shown in  FIG. 104  includes a convex part  258 ′ in a side face  274   b  in an ink supply port  276  side of the ink cartridge  272 . The convex part  258 ′ includes an elastic wave generating device  260 ′. Gelated material  280 ′ is provided in the side face  274   b  of the ink cartridge  272  so as to engage with the convex part  258 ′. According to the ink cartridge  272  shown in  FIG. 104 , when the ink remaining amount is becoming low and part of a radiating area of the elastic wave generating device  260 ′ is exposed from the liquid surface, the traveled time of the reflected wave of the elastic waves generated by the elastic wave generating device  260 ′ and the acoustic impedance continuously change corresponding to the change Δh2 of the liquid surface. The Δh2 denotes difference in the height of both ends of the gelated material  280 ′. Thus, the process from the ink-near-end state to the ink-end state of ink remaining amount can be accurately detected by detecting the degree of change in the traveled time of the reflected wave of the elastic wave generating device  260  or change in the acoustic impedance. 
   The ink cartridge according to the present embodiment further has a porous member  1050  provided inside the container  274 . The ink-jet recording apparatus includes a convex part  258 ′ in a side face  274   b  in an ink supply port  276  side of the ink cartridge  272 . The convex part  258 ′ includes an elastic wave generating device  260 ′. The side face  1056  of the porous member  1050  is parallel to the side face  274   b  of the container  274 . An ink layer  1060  is formed on the gap between the side face  1056  and the elastic wave generating device  260 ′. 
   The porous member  1050  prevents the waving or bubbling of ink inside the container  274 . Therefore, the elastic wave generating device  260 ′ can accurately detect the ink consumption status. 
   When ink is filled inside the container  274  and ink layer  1060 , the reflective wave of the elastic wave generated by the elastic wave generating device  260 ′ does not change. On the other hand, if ink inside the container  274  is consumed, gap arises in the part corresponding to the Δh2 which is a width in the height direction of the gelated material  280 ′ within the ink layer  1060 . With the arising of the gap in the ink layer  1060 , the reflective wave of the elastic wave generated by the elastic wave generating device  260 ′ gradually changes. Therefore, the elastic wave generating device  260 ′ can detect the ink consumption status when the is ink surface within the width Δh2 in the height direction. 
   If the ink surface is within the region of the Δh2, the elastic wave generating device  260 ′ can detect the ink surface. According to the ink cartridge according to the present embodiment, there is a gap between the side face  1056  of the porous member  1050  and the elastic wave generating device  260 ′, the elastic wave generating device  260 ′ can detect the ink surface within the region of the Δh2 even if the porous member  1050  is provided in the container  274 . Therefore, by widen the width of the Δh2, the elastic wave generating device  260 ′ can detect the ink surface when ink is filled in the container  274  until the ink surface when ink in the container  274  is nearly end. 
   In the above embodiments, the elastic wave is transmitted and received by the same elastic wave generating device  260  and  260 ′ when the ink remaining amount is detected based on the reflected wave at the liquid surface. The present invention is not limited thereby and for example, as still another embodiment the elastic wave generating device  260  may be provided separately as one for use in transmitting the elastic wave and other for receiving the elastic wave, so as to detect the ink remaining amount. 
     FIG. 105  is a cross sectional view of an embodiment of an ink cartridge for use with a single color, for example, the black ink. The ink cartridge shown in  FIG. 105  has a actuator  106 . An ink supply port  2  which comes in contact with an ink supply needle of the recording apparatus in a sealed manner is provided in a container  1  which houses the ink. In an outside portion of a bottom face  1   a  of the container  1 , the actuator  106  is mounted such that the actuator  106  can contact with ink inside the container  1  via the through hole  1   c  provided in the container  1 . In order that at a stage at which the ink K is almost used up, i.e. at the time when the ink becomes an ink-end state, the status around the actuator  106  can change from the liquid to the gas, the actuator  106  is provided in a slightly upward position from the ink supply port  2 . Moreover, an actuator  106  may be separately provided instead, so that the actuator  106  is used as an means for detecting liquid only. 
   Furthermore, a porous member  1050  is provided inside the container  1 . The porous member  1050  is provided around the actuator  106  inside the container  1 . A gap having a same depth with the through hole  1   c  is provided between the porous member  1050  and the actuator  106 . By providing the porous member  1050  inside the container  1 , the porous member  1050  prevents the waving or bubbling of ink inside the container  1  when the ink cartridge moves together with the recording head by the scanning operation during the printing process. Therefore, the bubble of ink is difficult to generate around the actuator  106 . The actuator  106  can thereby detect the ink consumption status accurately. 
   Moreover, the width of the gap between the porous member  1050  and the actuator  106  is not limited. To suppress the bubbling of ink as much as possible, the width of ink layer  1060  is reduced by providing the porous member  1050  on lower side of the container  1 . If the width of the ink layer  1060  is small, the actuator  106  can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container  1 . Therefore, the actuator  106  can accurately detect the ink quantity when the ink consumption status is near to the ink end status. Therefore, the porous member  1050  is preferably located nearby the actuator  106  without limiting the width of gap between the porous member  1050  and the actuator  106 . 
   Furthermore, the hole diameter of porous member  1050  is set such that the porous member  1050  does not absorbs ink existed in the through hole  1   c  before the ink surface reaches to the through hole  1   c . In other words, the porous member  1050  is designed such that the capillary force works in the porous member  1050  is smaller than the capillary force which can hold ink in the container  1 . Therefore, ink does not remain in the porous member  1050  by its own weight and exists in the through hole  1   c  when the ink inside the container  1  is in an ink near end status. Furthermore, an airhole, not shown in the figure, is provided on the container  1 . The airhole is provided on the upper side of the container  1  to communicate with outside of container  1 . Air is introduced inside the container  1  by the airhole, and ink flows downward by own weight with advance of ink consumption. The residual ink thereby stays in the through hole  1   c.    
   On the other hand, the hold diameter of the porous member  1050  can be set such that the porous member  1050  absorbs ink existed in the through hole  1   c  when the predetermined amount of the ink is consumed. That is, the hole diameter of the porous member  1050  is set that the capillary force works in the porous member  1050  is equal to or larger than the capillary force which can hold ink inside the container  1 . The porous member  1050  thereby absorbs ink existed in the through hole  1   c  when the predetermined amount of ink inside of the container  1  is consumed. Furthermore, the hole diameter of the porous member  1050  of a part nearby the ink supply port  2  is made smaller than the hole diameter of the other part of the porous member  1050 . Ink existed in the through hole  1   c  is thereby absorbed by the porous member  1050  and further supplied to the ink supply port  2  from the porous member  1050 . 
   For example, the hole diameter of the porous member  1050  is designed such that the porous member  1050  absorbs ink remained in the through hole  1   c  when the ink quantity in the ink cartridge becomes small amount in a degree that printing becomes defective. Furthermore, the hole diameter of the porous member  1050  is designed such that the porous member  1050  can send the ink, which is absorbed from the through hole  1   c  by the porous member  1050 , to the ink supply port  2 . The actuator  106  can thereby detects the ink end accurately when the predetermined amount of ink is consumed and prevents the defective printing. More specifically, the hole diameter of the porous member  1050  nearby the actuator  106  is made larger than the hole diameter of the porous member  1050  around the ink supply port  2 . 
   The porous member  1050  occupies more than half of the volume of the container  1 . However, a relatively small porous member, not shown in the figure, can be provided only around the actuator  106 . 
     FIG. 106  is a cross sectional view of the bottom part of the ink cartridge of the present embodiment. The ink cartridge of the present embodiment has a through hole  1   c  on the bottom face  1   a  of the container  1 , which contains ink. The bottom part of the through hole  1   c  is closed by the actuator  650  and forms an ink storing part. 
   The ink cartridge according to the present embodiment has a porous member  1050  provided inside the through hole  1   c . The porous member  1050  thereby contacts with the vibrating region of the actuator  650 . By providing the porous member  1050  to contact with the vibrating region of the actuator  650 , ink does not remained in the through hole  1   c.    
   For example, the hole diameter of the porous member  1050   b  provided around the through hole  1   c  is made smaller than the hole diameter of the porous member  1050   a  provided inside the through hole  1   c . The capillary force of the porous member  1050   a  around the through hole  1   c  thereby becomes smaller than the capillary force of the porous member  1050   a  inside of the through hole  1   c . Therefore, ink contained in the porous member  1050   a  inside the through hole  1   c  is absorbed by the porous member  1050   b  provided around the through hole  1   c  when the ink inside the ink cartridge is consumed. Thus, ink does not remain in the through hole  1   c . Therefore, the accuracy of detecting the ink consumption status inside the ink cartridge by the actuator  650  can be improved. 
     FIG. 107  is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown in  FIG. 105  and  FIG. 106 . A carriage  30  capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit  33 , while the recording head  31  is provided in a lower face of the subtank unit  33 . Moreover, the ink supply needle  32  is provided in an ink cartridge mounting face side of the subtank unit  33 . 
   While the recording apparatus is operating, a drive signal is supplied to the actuator  106  at a detection timing which is set in advance, for example, at a certain period of time. 
   By adhering the actuator  106  to the container  1 , a process of embedding electrodes for use in detecting the liquid surface is unnecessary in the course of forming the container  1 . Therefore, an injection molding process can be simplified and the leakage of the liquid from a place in which the electrodes are supposedly embedded can be avoided, thus improving the reliability of the ink cartridge. 
     FIG. 108  is a cross sectional view of another embodiment of a subtank unit  33 . The subtank unit  33  shown in  FIG. 108  comprises the actuator  106  and a porous member  1050 . In the embodiment shown in  FIG. 27 , the actuator  106  and the porous member  1050  are provided in the container  1  of the ink cartridge. However, as shown in  FIG. 108 , the actuator  106  and the porous member  1050  can be provided inside the subtank unit  33 . Furthermore, the actuator  106  and the porous member  1050  can be provided in both of inside the container  1  of the ink cartridge and the subtank unit  33 . 
   According to the embodiment shown in  FIG. 108 , the actuator  106  can detect the ink quantity and the existence of ink inside the subtank unit  33 . Furthermore, the porous member  1050  can prevents the waving and bubbling of ink inside the subtank unit  33 . Therefore, the actuator  106  can accurately detects the ink quantity and the existence of ink. Moreover, because the actuator  106  is provided inside the subtank unit  33 , the actuator  106  can detect the ink quantity and the existence of ink inside the subtank unit  33  even when there is no ink inside the ink cartridge. The ink jet recording apparatus thereby can judges whether the printing operation can be continued or not. 
   If the actuator  106  and the porous member  1050  are provided on both inside of the container  1  of the ink cartridge and the subtank unit  33 , the actuator  106  can detect the ink consumption status more accurately. Furthermore, the actuator  106  can detect the timing of ink end inside the container  1  of the ink cartridge. 
     FIG. 109  show ink cartridges according to still another embodiments of the present invention. In an embodiment shown in  FIG. 109 , a actuator  106  is mounted in a bottom face  1   a  formed a slope in the vertical direction. 
   According to the embodiments shown in  FIG. 109 , when part of the actuator  106  is exposed from the liquid surface, the residual vibration of the actuator  106  continuously changes. Therefore, the actuator  106  can accurately detect the ink consumption quantity by detecting the change of the acoustic impedance. For example, the actuator  106  can detect the ink surface while the ink surface exists within the region of the Δh1 shown in  FIG. 109 . 
   In the embodiment, the porous member  1050  is provided in the container  1 . The porous member  1050  prevents the waving and bubbling of ink inside the container  1 . The porous member  1050  thereby improves the accuracy of detecting the ink quantity by the actuator  106 . 
   In the embodiment shown in  FIG. 109 , the porous member  1050  is provided nearby the actuator  106 . However, the present embodiment does not provide the porous member  1050  inside the through hole  1   c . Therefore, ink directly contacts with the vibration region of the actuator  106 . Thus, the vibration region of the actuator  106  exposed to air with the increase in consumption of ink. Then, the vibration status at the vibration region of the actuator  106  changes. Therefore, to detect the ink quantity by the actuator  106  becomes easy. 
   To suppress the waving and bubbling of ink as much as possible, it is not preferable to have a gap between the porous member  1050  and the actuator  106 . On the other hand, it is also not preferable that the porous member  1050  adhere to the vibrating region of the actuator  106  in a degree that the vibrating section of the actuator  106  cannot vibrate. Therefore, the porous member  1050  is preferable to provided around the vibrating region of the actuator  106 . However, the porous member  1050  can be contacts with the vibrating region of the actuator  106  if the vibrating region of the actuator  106  can vibrate and detect the ink existence and the ink quantity. 
     FIG. 110  shows an ink cartridge according to still another embodiment of the present invention. Plural actuators  106   a ,  106   b , and  106   c  on the bottom face  1   a  formed a slope in the vertical direction spaced at an interval are provided in the container  1 . Furthermore, a porous member  1050  is provided inside the container  1 . The porous member  1050  prevents the actuators  106   a ,  106   b , and  106   c  to wrongly detect the ink consumption status as explained in the  FIG. 109 . 
   According to the present embodiment, depends on whether the ink is existed in the mounting position of each of the actuators  106   a ,  106   b , and  106   c , the amplitude of the residual vibration and a resonant frequency of the each of the actuators  106   a ,  106   b , and  106   c  differs at each of the mounting position of the actuators  106   a ,  106   b , and  106   c . Therefore, the existence of ink at the level of the mounting position of each of the actuators  106   a ,  106   b , and  106   c  can be detected by measuring the counter electromotive force of the residual vibration of each of the actuators  106   a ,  106   b , and  106   c . Therefore, residual quantity of ink can be detected step by step. For example, if the ink surface is at the level between the actuator  106   b  and the actuator  106   c , the actuator  106   a  detects non-ink status, and the other actuators  106   b  and  106   c  detects ink-exist status. By comprehensively judging these detecting results, it can be known that the ink surface positions between the mounting position of the actuator  106   b  and actuator  106   c.    
     FIG. 111  shows other embodiment of the through hole  1   c . In each of  FIGS. 111(A) , (B), and (C), the left hand side of the figure shows the status that there is no ink K in the through hole  1   c , and the right hand side of the figure shows the status that ink K is remained in the through hole  1   c . In the embodiment of  FIG. 28 , the side face of the through hole  1   c  is formed as the vertical wall. In  FIG. 111(A) , the side face  1   d  of the through hole  1   c  is slanted in vertical direction and opens with expanding to the outside. In  FIG. 111(B) , a stepped portion  1   e  and  1   f  are formed on the side face of the through hole  1   c . The stepped portion  1   f , which is provided above the stepped portion  1   e , is wider than the stepped portion  1   e . In  FIG. 111(C) , the through hole  1   c  has a groove  1   g  that extends to the direction in which ink is easily discharged, that is, the direction to a ink supply port  2 . 
   According to the shape of the through hole  1   c  shown in  FIG. 111(A)  to (C), the quantity of ink K in the ink storing part can be reduced. Therefore, because the M′cav can be smaller than the M′max explained in  FIG. 22  and  FIG. 23 , the vibration characteristic of the actuator  650  at the time of the ink end status can be greatly different with the vibration characteristic when enough quantity of ink K for printing is remained in the container  1 , and thus the ink end status can be reliably detected. 
   Furthermore, in the ink cartridge of the present embodiment, a porous member, not shown in  FIG. 111 , is provided around the through hole  1   c  of the  FIG. 111(A) ,  FIG. 111(B) , and  FIG. 111(C) . The porous member  1050  becomes easy to absorb ink inside the through hole  1   c  by forming the side face  1   d , stepped portion  1   e , and  1   f , or groove  1   g.    
     FIG. 112  is a slant view of the further other embodiment of the actuator. In this embodiment, the actuator  670  comprises a concave part forming base plate  80  and a piezoelectric element  82 . The concave part  81  is formed on the one side of the face of the concave part forming base plate  80  by the technique such as etching, and piezoelectric element  82  is mounted on the other side of the face of the concave part forming base plate  80 . The bottom portion of the concave part  81  operates as a vibrating region within the concave part forming base plate  80 . Therefore, the vibrating region of the actuator  670  is determined by the periphery of the concave part  81 . Furthermore, the actuator  670  has the similar structure with the structure of the actuator  106  shown in  FIG. 22 , in which the base plate  178  and the vibrating plate  176  is formed as one body. Therefore, the manufacturing process during the manufacturing an ink cartridge can be reduced, and the cost for manufacturing an ink cartridge also can be reduced. The actuator  670  has a size which can be embedded into the through hole  1   c  provided on the container  1 . By this embedding process, the concave part  81  can operates as the cavity. The actuator  106  shown in  FIG. 22  can be formed to be embedded into through hole  1   c  as actuator  670  shown in  FIG. 112 . Furthermore, a porous member  1050  is provided around the actuator  670 . 
   The actuator  106  of the ink cartridge  180 B shown in  FIG. 113  is mounted on the side wall of the supply port of the ink container  194 . The actuator  106  can be mounted on the side wall or bottom face of the ink container  194  if the actuator  106  is mounted nearby the ink supply port  187 . The actuator  106  is preferably mounted on the center of the width direction of the ink container  194 . Because ink is supplied to the outside through the ink supply port  187 , ink and actuator  106  reliably contacts until the timing of the ink near end by providing the actuator  106  nearby the ink supply port  187 . Therefore, the actuator  106  can reliably detect the timing of the ink near end. A porous member  1050  is provided around the actuator  106 . The porous member  1050  prevents the waving and the bubbling of ink and thereby prevents the actuator  106  to wrongly detect the ink consumption status. 
   Furthermore, by providing the actuator  106  nearby the ink supply port  187 , the setting position of the actuator  106  to the connection point on the carriage on the ink container becomes reliable during the mounting of the ink container on the cartridge holder of the carriage. It is because the reliability of coupling between the ink supply port with the ink supply needle is most important during the coupling of the ink container and the carriage. If there is even a small gap, the tip of the ink supply needle will be hurt or a sealing structure such as O-ring will be damaged so that the ink will be leaked. To prevent this kind of problems, the ink jet printer usually has a special structure that can accurately positioning the ink container during the mounting of the ink container on the carriage. Therefore, the positioning of the actuator  106  becomes reliable by arranging the actuator nearby the ink supply port. Furthermore, the actuator  106  can be further reliably positioned by mounting the actuator  106  at the center of the width direction of the ink container  194 . It is because the rolling is the smallest when the ink container rolls along an axis, the center of which is center line of the width direction, during the mounting of the ink container on the holder. 
     FIG. 114  shows further other embodiment of the ink cartridge  180 .  FIG. 114  shows a cross section of an ink cartridge  180 C. The semiconductor memory device  7  and the actuator  106  are formed on the same circuit board  610  in the ink cartridge  180 C. 
     FIG. 115  shows further other embodiment of the ink cartridge  180 . A plurality of actuators  106  is mounted on the side wall  194   b  of the ink container  194  in the ink cartridge  180 D shown in  FIG. 115 . It is preferable to use the plurality of the actuators  106  which is formed in one body as shown in  FIG. 26  for these plurality of actuators  106 . The plurality of actuators  106  is arranged on the side wall  194   b  with interval in vertical direction. By arranging the plurality of actuators  106  on the side wall  194   b  with interval in vertical direction, the residual quantity of ink can be detected step by step. 
   The ink cartridge  180 E shown in  FIG. 115  mounts a actuator  606  which is long in vertical direction on the side wall  194   b  of the ink container  194 . The change of the residual quantity of ink inside the ink container  194  can be detected continuously by the actuator  606  which is long in vertical direction. The length of the actuator  606  is preferably longer than the half of the height of the side wall  194   b . In  FIG. 115 , the actuator  606  has the length from the substantially from the top end to the bottom end of the side wall  194   b.    
   The ink cartridge  180 F shown in  FIG. 115  mounts a plurality of actuators  106  on the side wall  194   b  of the ink container  194  as the ink cartridge  180 D shown in  FIG. 115 . The ink cartridge  180 F further comprises the wave preventing wall  192 , which is long in vertical direction, along the side wall  194   b  with predetermined space with the side wall  194   b  such that the wave preventing wall  192  faces directly to the plurality of actuators  106 . It is preferable to use the plurality of the actuators  106  which is formed in one body as shown in  FIG. 26  for these plurality of actuators  106 . A gap which is filled with ink is formed between the actuator  106  and the wave preventing wall  192 . Moreover, the gap between the wave preventing wall  192  and the actuator  106  has a space such that the gap does not hold ink by capillary force. When the ink container  194  is rolled, ink wave is generated inside the ink container  194  by the rolling, and there is possibility that the actuator  106  malfunctions by detecting gas or an air bubble caused by the shock of the ink wave. By providing the wave preventing wall  192 , ink wave around the actuator  106  can be prevented so that the malfunction of the actuator  106  can be prevented. The wave preventing wall  192  also prevents the air bubble generated by the rolling of ink to enter to the actuator  106 . 
   Furthermore, a porous member  1050  is provided around the actuator  106  in the embodiments shown in  FIG. 115(A) ,  FIG. 115(B) , and  FIG. 115(C) . The porous member  1050  prevents the waving or bubbling of ink and prevents the actuator  106  to wrongly detect the ink consumption status. 
   The embodiment that the actuator  106  is mounted on an ink cartridge or a carriage, in which the ink cartridge is a separate body with the carriage and mounted on the carriage, has been explained above. However, the actuator  106  can be mounted on the ink tank which is mounted on the ink jet recording apparatus together with a carriage and formed together with a carriage as one body. Furthermore, the actuator  106  can be mounted on the ink tank of the off-carriage type. The off-carriage type ink tank is a separate body with a carriage and supplies ink to carriage through such as tube. Moreover, the actuator of the present embodiment can be mounted on the ink cartridge constituted so that a recording head and an ink container are formed as on body and possible to be exchanged. 
   Although the present invention has been described by way of exemplary embodiments, it should be understood that many changes and substitutions may be made by those skilled in the art without departing from the spirit and the scope of the present invention which is defined only by the appended claims. 
   The liquid container according to the present invention can reliably detect a liquid consumption status and dispense with a complicated sealing structure. 
   The liquid container according to the present invention can prevent the waving or bubbling of liquid around the piezoelectric device. 
   Furthermore, the liquid container according to the present invention has a piezoelectric device which can reliably detect a liquid consumption status by detecting the liquid surface even in the case that liquid inside the liquid container waves and bubbles. 
   Furthermore, the liquid container according to the present invention can reliably detect a liquid consumption status in the liquid container even if the piezoelectric device is mounted on the upper side of the liquid surface in the liquid container. 
   Furthermore, the liquid container according to the present invention can reliably detect a liquid consumption status in the liquid container even if the piezoelectric device is mounted on the top wall which is located above the liquid surface in the liquid container. Therefore, the degree of freedom to design the mounting position of the piezoelectric device can be increased. 
   Furthermore, the liquid container according to the present invention can reliably detect a liquid consumption status in the liquid container by reducing the amount of liquid remained inside of a cavity after the consumption of the liquid inside the liquid container.