Liquid container having liquid consumption detecting device

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.

The present patent application claims priority from Japanese patent applications Nos. H. 11-139683 filed on May 20, 1999, H. 11-147538 filed on May 27, 1999 and H. 11-256522 filed on Sep. 10, 1999, the contents 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 cartridge180is 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 maybe 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.

DETAILED DESCRIPTION OF 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. 1toFIG. 13is 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 container1which contains liquid K, a ink supply port2which supplies liquid K outside the container1, an actuator106which detects ink consumption status inside the container1, and a wave preventing wall which provided at the position that faced to the actuator106.

A packing ring4and a valve body6are provided in the ink supply port2. Referring toFIG. 18, the packing ring4is engaged with the ink supply needle32communicating with a recording head31, in a fluid-tight manner. The valve body6is constantly and elastically contacted against the packing ring4by way of a spring5. When the ink supply needle32is inserted, the valve body6is pressed by the ink supply needle32so as to open an ink passage, so that ink inside the container1is supplied to the recording head31via the ink supply port2and the ink supply needle32. On an upper wall of the container1, there is mounted a semiconductor memory means7which 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. InFIG. 1toFIG. 4, the wave preventing wall1192ato1192dis extended horizontally to the ink surface. Furthermore, the actuator106is mounted on the bottom face1awhich is located lower side of the ink surface. As shown in FIG.1(A), the ink supply port2that engages with the ink supply needle of the recording apparatus is provided on the container1which contains ink. The actuator106is mounted on the outside the bottom face1aof the container1so that the actuator106can contacts with ink inside the container1through the through hole1cwhich is provided on he container1. The actuator106is provided on the position which is higher than the ink supply port2so 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 actuator106can 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 container1has a side wall1020which extends substantially vertical direction to the liquid surface. The wave preventing wall1192ais fixed to the container1by mounting on the side wall1020of the container1.

A gap is provided between the actuator106and the wave preventing wall1192a. If ink is filled in the ink cartridge, ink is filled in the gap between the actuator106and the wave preventing wall1192a. On the other hand, the gap is designed such that ink is not held in the gap between the actuator106and the wave preventing wall1192aif ink in the ink cartridge is used up. In other words, no capillary force for holding ink arises between the actuator106and the wave preventing wall1192a.

Because the through hole1cis provided on the container1, ink remains in the through hole1ceven the ink inside the container1is consumed. Therefore, even when the ink cartridge vibrates by such as scanning operation during the printing process and thus ink nearby the ink supply port2rolls, ink does not mistakenly attach to the actuator106because ink previously remains in the through hole1c.Thus, there is only little possibility for the actuator106to mistakenly detect the existence of ink.

The wave preventing wall is provided to face to the actuator106in the ink cartridge according to the present embodiment. Therefore, even ink nearby the ink supply port2rolls, the wave preventing wall prevents the rolled ink to be contact with the actuator106. Therefore, Thus, there is only little possibility for the actuator106to 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 actuator106may detect mistakenly that there is no ink if the bubble attaches to the actuator106even if the ink is filled in the container1. 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 actuator106and contact with the actuator106because the wave preventing wall is provided such that the wave preventing wall faces to the actuator106.

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 breath ability 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 container1and the wave preventing wall is formed by a same material such that both of the container1and 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 port2to the recording head if the pressure inside the ink cartridge becomes extremely negative with the ink consumption, air hole, 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. 2shows a side cross sectional view of the other embodiment of the ink cartridge according to the present invention. As shown inFIG. 2, a wave preventing wall1192bis mounted on the side wall1030which 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 wall1192bof the ink cartridge of the present embodiment extends longer than the wave preventing wall1192aof the embodiment shown in FIG.1. Therefore, the wave preventing wall1192bcan effectively protects the actuator106from 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 wall1010and a side wall1030, which extend to the vertical direction to the ink surface, faces each other. The wave preventing wall1192cextends from the side wall1010to the side wall1030.

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 wall1020and the wave preventing wall1192cso that ink can pass through the gap.

FIG. 4shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. In the present embodiment, the actuator106is provided on the sloped face formed on the bottom face1a. The wave preventing wall1192dextends from the periphery of the ink supply port2within the inside wall of the container to face to the actuator106.

FIG.5(A) shows a side cross section of the further other embodiment of the ink cartridge according to the present invention.

InFIG. 5toFIG. 7, the actuator106is mounted on the side wall1030which extends to the vertical direction to the ink surface. Furthermore, the wave preventing wall1192eto1192gextends substantially vertical to the ink surface, that is, parallel with the side wall1030.

The wave preventing wall1192eis provided on the position where directly faces to the actuator106. The wave preventing wall1192eextends from the bottom face1a. Furthermore, a gap is provided between the top wall1040and the top of wave preventing wall1192e.

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 wall1020and the wave preventing wall1192eso that ink can pass through the gap. Because of the gap, ink does not remain in the actuator106side of the container1, which is formed by partitioning the container1by the wave preventing wall1192e, even if ink is consumed. Therefore, the level of ink surface around the actuator106is always equal to the level of the ink surface of the other region of the container1. Thus, the actuator106does not detect mistakenly the ink consumption status.

Furthermore, the length of the wave preventing wall1192efrom the bottom face1acan be changed according to the height of the actuator106to 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 wall1192eand the side wall1020can be changed according to the position of the actuator106on the width direction of the ink cartridge, the magnitude of the vibrating region of the actuator106, 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 actuator106is mounted on the side wall1030. A wave preventing wall1192fis mounted on the position where directly faces to the actuator106. The wave preventing wall1192fextends from the top wall1040. Furthermore, a gap is provided between the bottom face1aand the wave preventing wall1192f.

FIG.6(B) shows a cross sectional view from the front of the ink cartridge of FIG.6(A). The wave preventing wall1192fis coupled to the side wall1020liquid tightly so that ink can not pass through between the wave preventing wall1192fand the side wall1020. By this configuration, ink remains only in the side of the actuator106which is formed by partitioning the container1by the wave preventing wall1192f, even if ink is consumed. However, when ink surface reaches to the lower end of the wave preventing wall1192f, gas enters to the actuator106side of the container1partitioned by the wave preventing wall1192f. By the entering of the gas, ink remained in the actuator106side of the container1partitioned by the wave preventing wall1192fflows out to the ink supply port2side, then the medium exits around the actuator106changes from ink to gas. Thereby the actuator106can detect that the ink inside the ink cartridge is in status of ink end. According to the present embodiment, lower end192adetermines the level of ink surface to be an ink end. Therefore, as far as the actuator106is provided on the position upper than the lower end192ato the ink surface, actuator106can be located in any position on the wall face1030. An air hole, which introduces gas, is provided on the top wall of the ink supply port2side of the container1partitioned by the wave preventing wall1192f.

FIG.7(A) shows a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator106is mounted on the side wall1030which is vertical to the ink surface among the wall of the container1. A wave preventing wall1192gis provided on the position where directly faces to the actuator106. The wave preventing wall1192gextends from the bottom face1ato the top wall1040.

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 wall1192gand the side wall1020so that ink can pass through the gap. By this configuration, ink does not remain in the side of the actuator106which is formed by partitioning the container1by the wave preventing wall1192g, even if ink is consumed. Therefore, the level of ink surface around the actuator106is always equal to the level of ink surface of the other region of container1. Furthermore, the interval of the gap between the wave preventing wall1192gand the side wall1020can be changed according to the position of the actuator106on the width direction of the ink cartridge, or the characteristic of ink.

FIG. 8toFIG. 11show a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator106is mounted on the side wall1010where the ink supply port2is provided.

InFIG. 8, the wave preventing wall1192iis provided on the position where directly faces to the actuator106. The wave preventing wall1192iextends from the supply port wall2awhich is a outside wall of the ink supply port2among the inside wall nearby the ink supply port2of the ink cartridge. On the other hand, a gap is provided between the top wall1040and the wave preventing wall1192i.

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 wall1192iand the side wall1020. Because of the gap, ink does not remain in the actuator106side of the container1, which is formed by partitioning the container1by the wave preventing wall, even if ink is consumed1192ias the embodiment shown in FIG.5. Therefore, the level of ink surface around the actuator106is always equal to the level of the ink surface of the other region of the container1.

InFIG. 9, the wave preventing wall1192jis provided on the position where directly faces to the actuator106. The wave preventing wall1192jextends from the top wall1040. On the other hand, a gap is provided between the supply port wall2aand the wave preventing wall1192j.

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 wall1192jis coupled to the side wall1020liquid so that ink can not pass through between the wave preventing wall1192jand the side wall1020. Therefore, as the embodiment shown inFIG. 6, as far as the actuator106is provided on the position upper than the lower end192ato the ink surface, the actuator106can be located in any position on the wall face1030.

InFIG. 10, the wave preventing wall1192kis provided on the position where directly faces to the actuator106. The wave preventing wall1192kextends from the top wall1040to the supply port wall2a.

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 forFIG. 10. Agap is provided between the wave preventing wall1192kand the side wall1020as shown in FIG.7(B). Therefore, ink does not remain in the side of the actuator106which is formed by partitioning the container1by the wave preventing wall1192k, even if ink is consumed as same as the embodiment of FIG.5. Therefore, the level of ink surface around the actuator106is always equal to the level of ink surface of the other region of container1.

FIG. 11toFIG. 13show a side cross section of the further other embodiment of the ink cartridge according to the present invention. The actuator106is mounted on the boundary between the bottom face1a, which is located below the ink surface, and the side wall1030, which extends vertical to the ink surface.

InFIG. 11, a wave preventing wall1192mis fixed to the container1such that one end of a wave preventing wall1192mis connected to the bottom face1a, and the other end of which is connected to the side wall1030. The wave preventing wall1192mis provided on the container1such that the wave preventing wall1192mdirectly faces to the actuator106and slopes to the ink surface. There is a gap between the side wall1020and the wave preventing wall1192mamong the wall of the container1in the present embodiment. Therefore, the level of ink surface around the actuator106is always equal to the level of ink surface of the other region of container1even if ink is consumed. Furthermore, the shape of the wave preventing wall1192mof the present embodiment is substantially plane shape.

Because the ink cartridge according the present embodiment mounting the actuator106on the boundary of the wall of the container1, the positioning of the actuator106on the container1during the manufacturing of the ink cartridge becomes easy. Moreover, because the length or the width of the wave preventing wall1192mcan be shorten, the quantity of the material used for manufacturing the wave preventing wall1192mis reduced. Furthermore, even in the case of manufacturing the wave preventing wall1192mas a independent material with the container1, it is relatively easy to positioning the wave preventing wall1192mon the boundary of the wall of the container1. Therefore, the manufacturing of the ink cartridge180becomes easy.

InFIG. 12, the position of mounting the actuator106and the wave preventing wall1192non the container1is same as the embodiment of the FIG.11. On the other hand, the shape of the wave preventing wall1192nis a part of the spherical shell in the present embodiment. By shaping the wave preventing wall1192nin a shape of spherical shell, the distance between the actuator106and the all the part of the wave preventing wall1192nbecomes equal. Thereby the wave preventing wall1192ndoes not influence the residual vibration detected by the actuator106.

Furthermore, the wave preventing wall1192ncan be formed as a part of the hollow cylindrical shape.

InFIG. 13, the position of mounting the actuator106and the wave preventing wall1192pon the container1is same as the embodiment of the FIG.11. On the other hand, the wave preventing wall1192pis formed in an L-shape in the present embodiment. The wave preventing wall1192pis provided on the container1such that the wave preventing wall1192phas a same distance with the side wall1030and the bottom face1a. By shaping the wave preventing wall1192nin a L-shape and reducing the gap between the wave preventing wall1192pand the actuator106as long as the capillary force does not arise between the wave preventing wall1192pand the actuator106, the waving and bubbling of ink around the actuator106can be effectively prevented.

FIG. 14is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container8is divided by division walls into three ink chambers9,10and11. Ink supply ports12,13and14are formed for the respective ink chambers. In a bottom face8aof the respective ink chambers9,10and11, the respective actuator15,16and17are mounted on the container8so that the actuator can contact with the ink which is housed in each ink chamber via the through hole provided on the container8.

Each of three different wave preventing walls, not shown in the figure, is provided on the position of each of inside of the ink container9,10and11such that the each of the wave preventing walls faces to the each of actuators15,16, and17.

FIG. 15is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container8is divided by partition walls into three ink chambers9,10and11. Ink supply ports12,13and14are formed for the respective ink chambers. In a side wall1028which extends vertically to the ink surface of the respective ink chambers9,10and11, the respective actuators15,16and17are mounted on the container8. Each of the actuators15,16, and17is mounted on the each of the ink chambers9,10,11so that the each of the actuators15,16, and17can contact with the ink which is housed in each ink chamber via the through hole, not shown in the figure, provided on the container8. The actuator16is mounted at one of the partition wall, which is provided between the ink chamber9and the ink chamber10, and the partition wall, which is provided between the ink chamber10and the ink chamber11.

Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber9,10, and11such that each of the wave preventing walls faces to the actuators15,16, and17and extends to the vertical direction to the ink surface.

FIG. 16is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container8is divided by partition walls into three ink chambers9,10and11. Ink supply ports12,13and14are formed for the respective ink chambers. Each of actuators15,16and17is mounted on the container8just nearby the each of the ink supply port12,13, and14, respectively. Each of the actuators15,16, and17is mounted on the each of the ink chambers9,10,11so that the each of the actuators15,16, and17can contact with the ink which is housed in each ink chamber via the through hole, not shown in the figure, provided on the container8.

Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber9,10, and11such that each of the wave preventing walls faces to the actuators15,16, and17as shown inFIG. 8to FIG.11.

FIG. 17is a perspective view of the ink cartridge which stores plural types of inks, viewed from a back side thereof, according to an embodiment. A container8has same constitute element as shown inFIG. 14toFIG. 16. Asloped face which slopes to the ink surface is provided on the bottom face8a. Each of actuators15,16and17is mounted on the sloped face1025of each of the ink chambers9,10, and11.

Each of the wave preventing walls, not shown in the figure, is provided inside the each of the ink chamber9,10, and11as shown in FIG.4.

Furthermore, the actuators15,16, and17can be provided on the boundary of the walls that adjoin each other in the container8. In this case, each of the wave preventing walls is provided inside the each of the ink chambers9,10, and11as shown inFIG. 11to FIG.13.

FIG. 18is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown inFIG. 1. Acarriage30capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit33, while the recording head31is provided in a lower face of the subtank unit33. Moreover, the ink supply needle32is provided in an ink cartridge mounting face side of the subtank unit33. In the present embodiment, the ink cartridge shown inFIG. 1is used. Therefore, the wave preventing wall1192ais mounted on the position which faces to the actuator106. However, the ink cartridge shown inFIG. 2toFIG. 17can be used instead of the ink cartridge shown in FIG.1. Therefore, the wave preventing wall shown inFIG. 2topFIG. 17can be used for the present embodiment.

FIG. 19is a detailed cross sectional view of a subtank unit33as an embodiment of the liquid container according to the present invention. The subtank unit33comprises the ink supply needle32, the ink chamber34, a flexible valve36and a filter37. In the ink chamber34, the ink is housed which is supplied from the ink cartridge via ink supply needle32. The flexible valve36is so designed that the flexible valve36is opened and closed by means of the pressure difference between the ink chamber34and the ink supply passage35. The subtank unit33is so constructed that the ink supply passage35is communicated with the recording head31so that the ink can be supplied up to the recording head31.

Furthermore, the actuator106can be mounted on the side wall1050which extends to vertical direction to the ink surface among the wall of the subtank unit33. The actuator106is mounted on the side wall1050so that the actuator106can contacts with ink inside the ink chamber34through the through hole1001cwhich is provided on the side wall1050. The wave preventing wall1192qextends from the filter37to the upward direction to the ink surface so that the wave preventing wall1192qfaces to the actuator106. A gap is provided between the top wall1060, which locates upward the ink surface, and the wave preventing wall1192q.

A gap is provided between the actuator106and the wave preventing wall1192q. If ink is filled in the ink cartridge, ink is filled in the gap between the actuator106and the wave preventing wall1192q. On the other hand, if the ink inside the ink cartridge is consumed, ink is not held in the gap between the actuator106and the wave preventing wall1192q. That is, the capillary force, which holds ink, does not works between the actuator106and the wave preventing wall1192q.

The cross section of the subtank unit33viewed from the direction of the side wall1050is 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 wall1050and the wave preventing wall1192q. The level of the ink surface around the actuator106is always equal to the level of the ink surface of the other region of the container1. Therefore, with the consumption of the ink inside the ink chamber34, the level of ink surface between the side wall1050and the wave preventing wall1192qalso decreases. The actuator106thereby does not mistakenly detect the ink consumption status.

Furthermore, the length of the wave preventing wall1192qfrom the filter37can be changed according to the position of the actuator106to 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 wall1192qand the side wall1020can be changed according to the position of the actuator106on the subtank unit33, the magnitude of the vibrating region of the actuator106, or the characteristic of ink.

Referring toFIG. 18, when the ink supply port2of the container1is inserted through the ink supply needle32of the subtank unit33, the valve body6recedes against the spring5, so that an ink passage is formed and the ink inside the container1flows into the ink chamber34. At a stage where the ink chamber34is filled with ink, a negative pressure is applied to a nozzle opening of the recording head31so as to fill the recording head with ink. Thereafter, the recording operation is performed.

When the ink is consumed in the recording head31by the recording operation, a pressure in the downstream of the flexible valve36decreases. Then, the flexible valve36is positioned away from a valve body38so as to become opened as shown in FIG.19. When the flexible valve36is opened, the ink in the ink chamber34flows into the recording head31through the ink passage35. Accompanied by the ink which has flowed into the recording head31, the ink in the container1flows into the subtank unit33via the ink supply needle32.

Moreover, the actuator106and the wave preventing wall are provided at least one of the ink cartridge and the subtank unit. However, the actuator106and the wave preventing wall can be provided both of the ink cartridge and the subtank unit.

By providing the actuator106and 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 actuator106, which is mounted on the ink cartridge, detects the ink end or that the actuator106mounted on the subtank unit33detects 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 actuator106, which is mounted on the ink cartridge, detects the ink end and that the actuator106mounted on the subtank unit33detects the ink end.

While the recording apparatus is operating, a drive signal is supplied to the actuator106at a period which is set in advance.

FIG. 20is a cross sectional view of another embodiment of a subtank unit33of the liquid container according to the present invention. The actuator106is mounted on the side wall1050. The wave preventing wall1192rextends from the top wall1060, which is located upside of the ink surface, downward to the ink surface. There is a gap between the lower end192aof the wave preventing wall1192rand the filter37. Moreover, a gap is provided between the wave preventing wall1192rand the side wall adjacent to the side wall1050. No capillary force, which holds ink, arises between the wave preventing wall1192rand the actuator106as similar to the embodiment shown in FIG.19.

Because a gap is provided between the wave preventing wall1192rand the side wall adjacent to the side wall1050, the level of the ink surface around the actuator106is always equal to the level of the ink surface of the other region of the container34. Therefore, the actuator106detects the ink end status by detecting the ink surface at the mounting position of the actuator106.

FIG. 21is a cross sectional view of further another embodiment of a subtank unit33of the liquid container according to the present invention. The actuator106is mounted on the side wall1050. The wave preventing wall1192sextends from the top wall1060until the filter37. No capillary force, which holds ink, arises between the wave preventing wall1192sand the actuator106as similar to the embodiment shown in FIG.19.

Furthermore, a gap is provided between the wave preventing wall1192sand the side wall adjacent to the side wall1050. Therefore, the level of the ink surface around the actuator106is always equal to the level of the ink surface of the other region of the container34.

FIG.22andFIG. 23shows a detail and equivalent circuit of an actuator106, 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 actuator106. FIG.22(B) shows a B—B cross-section of the actuator106. FIG.22(C) shows a C—C cross-section of the actuator106. FIG.23(A) and FIG.23(B) shows an equivalent circuit of the actuator106. Each of FIG.23(C) and FIG.23(D) shows the actuator106and around the actuator106, and the equivalent circuit of the actuator106when an ink is filled in the ink cartridge. FIG.23(E) and FIG.23(F) shows the actuator106and around the actuator106, and the equivalent circuit of the actuator106when there is no ink in the ink cartridge.

The actuator106includes abase plate178, a vibrating plate176, a piezoelectric layer160, an upper electrode164and a lower electrode166, an upper electrode terminal168, a lower electrode terminal170, and a supplementary electrode172. The base plate178has a circular shape opening161on approximately its center. The vibrating plate176is provided on one of the face, which is called as “right side” in following, of the base plate178such as to cover the opening161. The piezoelectric layer160is disposed on right side of the surface of the vibrating plate176. The upper electrode164and the lower electrode166sandwich the piezoelectric layer160from both sides. The upper electrode terminal168connects to the upper electrode164electrically. The lower electrode terminal170connects to the lower electrode166electrically. The supplementary electrode172is disposed between the upper electrode164and the upper electrode terminal168and connects both of the upper electrode164and the upper electrode terminal168. Each of the piezoelectric layer160, upper electrode164, and the lower electrode166has a circular portion as its main portion. Each of the circular portion of the piezoelectric layer160, the upper electrode164, and the lower electrode166form a piezoelectric element.

The vibrating plate176is formed on the right side of the surface of the base plate178to cover the opening161. The cavity162is formed by the portion of the vibrating plate176, which faces the opening161, and the opening161of the on the surface of the base plate178. The face of the base plate178which is opposite side of the piezoelectric element, called as “back side” in following, is faced with the liquid container side. The cavity162is constructed such that the cavity162contacts with liquid. The vibrating plate176is mounted on the base plate178such that the liquid does not leak to the right side of the surface of the base plate178even if the liquid enters inside the cavity162.

The lower electrode166is located on the right side of the vibrating plate176, that is, opposite side against the liquid container. The lower electrode166is provided on the vibrating plate176such that the center of the circular portion of the lower electrode166, which is a main portion of the lower electrode166, and the center of the opening161substantially matches. The area of the circular portion of the lower electrode166is set to be smaller than the area of the opening161. The piezoelectric layer160is formed on the right side of the surface of the lower electrode166such that the center of the circular portion and the center of the opening161substantially match. The area of the circular portion of the piezoelectric layer160is set to be smaller than the area of the opening161and larger than the area of the circular portion of the lower electrode166.

The upper electrode164is formed on the right side of the surface of the piezoelectric layer160such that the center of the circular portion, which is a piezoelectric layer160, and the center of the opening161substantially match. The area of the circular portion of the upper electrode164is set to be smaller than the area of the circular portion of the opening161and the piezoelectric layer160and larger than the area of the circular portion of the lower electrode166.

Therefore, the main portion of the piezoelectric layer160has a structure to be sandwiched by the main portion of the upper electrode164and the main portion of the lower electrode each from right side face and back side face, and thus the main portion of the piezoelectric layer160can effectively drive and deform the piezoelectric layer160. The circular portion, which is a main portion of each of the piezoelectric layer160, the upper electrode164, and the lower electrode166, forms the piezoelectric element in the actuator106. As explained above, the electric element contacts with the vibrating plate. Within the circular portion of the upper electrode164, circular portion of the piezoelectric layer160, the circular portion of the lower electrode, and the opening161, the opening161has the largest area. By this structure, the vibrating region which actually vibrates within the vibrating plate is determined by the opening161. Furthermore, each of the circular portion of the upper electrode164and the circular portion of the piezoelectric layer160and the circular portion of the lower electrode has smaller area than the area of the opening161, The vibrating plate becomes easily vibrate. Within the circular portion of the lower electrode166and the circular portion of the upper electrode164which connects to the piezoelectric layer160electrically, the circular portion of the lower electrode166is smaller than the circular portion of the upper electrode164. Therefore, the circular portion of the lower electrode166determines the portion which generates the piezoelectric effect within the piezoelectric layer160.

The center of the circular portion of the piezoelectric layer160, the upper electrode164, and the lower electrode166, which form the piezoelectric element, substantially match to the center of the opening161. Moreover, the center of the circular shape opening161, which determines the vibrating section of the vibrating plate176, is provided on the approximately center of the actuator106. Therefore, the center of the vibrating section of the actuator106matches to the center of the actuator106. Because the main portion of the piezoelectric element and the vibrating section of the vibrating plate176have a circular shape, the vibrating section of the actuator106is symmetrical about a center of the actuator106.

Because the vibrating section is symmetrical about a center of the actuator106, 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 actuator106, the actuator106is 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 element174decreases. 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 actuator106is easy to assemble to the liquid container.

Furthermore, because the vibrating section of the vibrating plate176has 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 layer160, 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 plate176because 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 plate176is larger than the displacement generated by the vibration of the base plate178. The actuator106has a two layers structure that is constituted by the base plate178having a small compliance which means it is difficult to be displaced by the vibration, and the vibrating plate176having a large compliance which means it is easy to be displaced by the vibration. By this two layers structure, the actuator106can be reliably fixed to the liquid container by the base plate178and at the same time the displacement of the vibrating plate176by 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 plate176is 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 actuator106locates on the periphery of the cavity162, that is, around the margin of the opening161.

The upper electrode terminal168is formed on the right side of the surface of the vibrating plate176to be electrically connected to the upper electrode164through the supplementary electrode172. The lower electrode terminal170is formed on the right side of the surface of the vibrating plate176to be electrically connected to the lower electrode166. Because the upper electrode164is formed on the right side of the piezoelectric layer160, there is a difference in depth that is equal to the sum of the thickness of the piezoelectric layer160and the thickness of the lower electrode166between the upper electrode164and the upper electrode terminal168. It is difficult to fill this difference in depth only by the upper electrode164, and even it is possible to fill the difference in depth by the upper electrode164, the connection between the upper electrode164and the upper electrode terminal168becomes weak so that the upper electrode164will be cut off. Therefore, this embodiment uses the supplementary electrode172as a supporting member to connects the upper electrode164and the upper electrode terminal168. By this supplementary electrode172, both of the piezoelectric layer160and the upper electrode164are supported by the supplementary electrode172, and thus the upper electrode164can have desired mechanical strength, and also the upper electrode164and the upper electrode terminal168can be firmly connected.

The piezoelectric element and the vibrating section which faces to the piezoelectric element within the vibrating plate176constitute the vibrating section which actually vibrates in the actuator106. Moreover, it is preferable to form the actuator106in one body by firing together the member included in the actuator106. By forming the actuator106as one body, the actuator106becomes easy to be handled. Further, the vibration characteristic increases by increasing the strength of the base plate178. That is, by increasing the strength of the base plate178, only the vibrating section of the actuator106vibrates, and the portion other than the vibrating section of the actuator106does not vibrates. Furthermore, the prevention of the vibration of the portion other than the vibrating section of the actuator106can be achieved by increasing the strength of the base plate178and at the same time forming the actuator106as thinner and smaller as possible and forming the vibrating plate176as 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 layer160. It is preferable to use zirconia or alumina as a material of the base plate178. Furthermore, it is preferable to use same material as base plate178for a material of vibrating plate176. The metal such as gold, silver, copper, platina, aluminum, and nickel having a electrical conductivity can be used for the material of the upper electrode164, the lower electrode166, the upper electrode terminal168, and the lower electrode terminal170.

The actuator106constructed as explained above can be applied to the container which contains liquid. For example, the actuator106can 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 actuator106shown in the FIG.22andFIG. 23is mounted on the predetermined position on the liquid container so that the cavity162can contact w3ith the liquid contained inside the liquid container. When the liquid container is filled with liquid sufficiently, the inside and outside of the cavity162is 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 cavity162or that liquid is remained only in the cavity162and air exits on outside the cavity162. The actuator106detects at least the difference in the acoustic impedance occurred by this change in condition. By this detection of the difference in acoustic impedance, the actuator106can detects the whether the liquid is sufficiently filled in the liquid container or liquid is consumed more than predetermined level. Furthermore, the actuator106can 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 actuator106to the transmission circuit, the actuator106can 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 actuator106is a portion which constitutes the cavity162that is determined by the opening161within the vibrating plate176. When liquid is sufficiently filled in the liquid container, liquid is filled in the cavity162, 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 cavity162is provided on the actuator106of the present invention, and it can be designed that the liquid inside the liquid container remains in the vibrating region of the actuator106by the cavity162. The reason will be explained as follows.

Depends on the mounting position and mounting angle of the actuator106on 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 actuator106will 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 cavity162of the actuator106is set as the threshold value of the existence of the liquid. That is, if the liquid does not exist around the cavity162, 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 cavity162, 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 actuator106is 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 actuator106, 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 actuator106. By setting the threshold value in this way, the actuator106can judge that there is no ink in the liquid container even if the ink in the cavity is dried and disappeared. Furthermore, the actuator106can 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 actuator106obtained by measuring the counter electromotive force will be explained reference to FIG.22andFIG. 23. Avoltage is applied on each of the upper electrode164and the lower electrode166through the upper electrode terminal168and the lower electrode terminal170. The electric field is generated on the portion of the piezoelectric layer160where the piezoelectric layer160is sandwiched by the upper electrode164and the lower electrode166. By this electric field, the piezoelectric layer160deforms. By the deformation of the piezoelectric layer160, the vibrating region within the vibrating plate176deflects and vibrates. For some period after the deformation of the piezoelectric layer160, the vibration with deflection remains in the vibrating section of the actuator106.

The residual vibration is a free oscillation of the vibrating section of the actuator106and 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 layer160. Because the residual vibration vibrates the vibrating section of the actuator106, the residual vibration also deforms the piezoelectric layer160. Therefore, the piezoelectric layer160generates the counter electromotive force. This counter electromotive force is detected through the upper electrode164, the lower electrode166, the upper electrode terminal168, and the lower electrode terminal170. 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 actuator106when 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 actuator106and the cavity162when 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+Melectrode1+Melectrode2+Mvib  (2)
Here, Mpzt is obtained by dividing the product of the thickness of the piezoelectric layer160in the vibrating section and the density of the piezoelectric layer160by the area of the piezoelectric layer160. Melectrode1is obtained by dividing the product of the thickness of the upper electrode164in the vibrating section and the density of the upper electrode164by the area of the upper electrode164. Melectrode2is obtained by dividing the product of the thickness of the lower electrode166in the vibrating section and the density of the lower electrode166by the area of the lower electrode166. Mvib is obtained by dividing the product of the thickness of the vibrating plate176in the vibrating section and the density of the vibrating plate176by the area of the vibrating region of the vibrating plate176. However each of the size of the area of the vibrating region of the piezoelectric layer160, the upper electrode164, the lower electrode166, and vibrating plate176have 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 layer160, the upper electrode164, and the lower electrode166is 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 electrode164, the lower electrode166, the piezoelectric layer160, and the vibrating plate176in the actuator106. Moreover, the compliance Cact is a compliance of the portion formed by the each of the vibrating region of the upper electrode164, the lower electrode166, the piezoelectric layer160, and the vibrating plate176.

FIG.23(A), FIG.23(B), FIG.23(D), and FIG.23(F) show the equivalent circuit of the vibrating section of the actuator106and the cavity162. In these equivalent circuits, Cact shows a compliance of the vibrating section of the actuator106. Each of the Cpzt, Celectrode1, Celectrode2, and Cvib shows the compliance of the vibrating section of the piezoelectric layer160, the upper electrode164, the lower electrode166, and the vibrating plate176. 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 actuator106when the liquid is sufficiently filled in the liquid container, and the periphery of the vibrating region of the actuator106is filled with the liquid. The M′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 actuator106is filled with the liquid. The M′max can be expressed as
M′max=(π*ρ/(2*k3))*(2*(2*k*a)3/(3*π))/(π*a2)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 actuator106is 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 actuator106and the cavity162as 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 actuator106is filled with the liquid.

FIG.23(E) shows the cross section of the actuator106when the liquid in the liquid container is consumed, and there is no liquid around the vibrating region of the actuator106, and the liquid remains in the cavity162of the actuator106. 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 actuator106becomes gas or vacuum with the liquid remaining in the cavity162, 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 actuator106. If this vibrating region is circular shape having a radius of “a”, the S can be shown as S=π*a2. 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 actuator106is 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 actuator106, and the liquid is remained in the cavity162.

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 actuator106, and the liquid is remained in the cavity162, 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 actuator106is filled with the liquid.

FIG.23(F) shows an equivalent circuit of the vibrating section of the actuator106and the cavity162in 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 actuator106, and the liquid remains in the cavity162of the actuator106.

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 actuator106. 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 actuator106. 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 actuator106is 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 actuator106, 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 actuator106, 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 actuator106, and the ink remains in the cavity162, 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 cavity162of the actuator106as small as possible, that is, forming the thickness of the base plate178as 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 actuator106is 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 actuator106, 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 actuator106can gradually detect the ink consumption status.

Furthermore, by enlarge or lengthen the vibrating section of the actuator106and arrange the actuator106along a lengthwise direction, the “S” in the equation (6) changes according to the change of ink level with ink consumption. Therefore, the actuator106can detect the process while the ink is gradually consumed. For example, the actuator106is 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 actuator106, 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 radius2aof the cavity162(refer to FIG.23(C)), the actuator106can 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 actuator106is 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 actuator106can 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 actuator106. For example, the case when the actuator106is 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 actuator106includes 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 actuator106as 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; pair is a density of an air; pink 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 actuator106is 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 actuator106. 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 actuator106is 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 actuator106is ink only, and the region, where the medium involved with the vibration of the actuator106is gas, can be expressed as parallel circuit. If let the area of the region where the medium involved with the vibration of the actuator106is ink only as Sink, and let the area of the region where the medium involved with the vibration of the actuator106is gas only as Sair, the following equation (9) can be obtained.
1/M′=1/M′air+1/M′ink=Sair/(ρair*t-air)+Sink/(ρink*t-ink)  (9)

The equation (9) can be applied when the ink is not held in the cavity of the actuator106. 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 plate178is thick, that is, the depth of the cavity162is 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 actuator106for detecting the existence of the liquid is more accurate than the method which calculates the quantity of ink consumption by the software because the actuator106detects 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 actuator106to 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 actuator106, 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 actuator106during the operation of the actuator106can be reduced by setting the vibrating frequency of the piezoelectric layer160out 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 actuator106can distinguish the ink tank which contains the different type of the ink.

The condition when the actuator106can 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 cavity162of the actuator106even when the liquid inside the liquid container is empty. The actuator106can detect the status of the liquid even when the liquid is not filled in the cavity162if the actuator106can detect the status of the liquid when the liquid is filled in the cavity162.

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 inertance M′. 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 cavity162. 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 M′ does not change in this case. Therefore, the actuator106cannot 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 cavity162and 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 actuator106can detect the status of the liquid in the liquid container.

The condition whether the actuator106can 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 cavity162of the actuator106, and the liquid container is empty. The condition M′max>M′cav, on which the actuator106can accurately detect the status of the liquid, does not depend on the shape of the cavity162.

Here, the M′cav is the mass of the liquid of the volume which is substantially equal to the volume of the cavity162. Therefore, the condition, which can detect the status of the liquid accurately, can be expressed as the condition of the volume of the cavity162from the inequality M′max>M′cav. For example, if let the radius of the opening161of the circular shaped cavity162as “a” and the thickness of the cavity162as “d”, then the following in equality can be obtained.
M′max>ρ*d/πa2(10)
By expanding the inequality (10), the following condition can be obtained.
a/d>3*π/8  (11)
The inequality (10) and (11) are valid only when the shape of the cavity162is circular. By using the equation when the M′max is not circular and substituting the area πa2with 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 actuator106has the cavity162which has the radius of the opening161“a” and the depth of the cavity “d” that satisfy the condition shown in inequality (11), the actuator106can detect the liquid status without malfunction even when the liquid container is empty and the liquid is remained in the cavity162.

Because the additional inertance influences the acoustic impedance characteristic, it can be said that the method of measuring the counter electromotive force generated in actuator106by residual vibration measures at least the change of the acoustic impedance.

Furthermore, according to the present embodiment, the actuator106generates the vibration, and the actuator106itself measures the counter electromotive force in actuator106which is generated by the residual vibration remained after the vibration of the actuator106. However, it is not necessary for the vibrating section of the actuator106to provide the vibration to the liquid by the vibration of the actuator106itself which is generated by the driving voltage. Even the vibrating section itself does not oscillates, the piezoelectric layer160deflects 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 layer160and transfer this counter electromotive force voltage to the upper electrode164and the lower electrode166. 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 actuator106and the measuring method of the residual vibration. The change of the ink level at the level of the mounting position of the actuator106in 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 actuator106. 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 actuator106, and the horizontal axis shows the time. By the residual vibration of the actuator106, 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 actuator106oscillates, 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 actuator106. FIG.25(B) shows the waveform when the ink level is below the level of the mounting position of the actuator106. 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 actuator106becomes 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. InFIG. 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 actuator106oscillates, 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 actuator106oscillates, 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. 26shows the manufacturing method of the actuator106. A plurality of the actuators106, four numbers in the case of theFIG. 26, are formed as one body. The actuator106shown inFIG. 27is manufactured by cutting the plurality of actuator106, which is formed in one body as shown inFIG. 26, at each of the actuator106. If the each of the piezoelectric elements of the each of the plurality of the actuator106, which is formed in one body as shown inFIG. 26, are circular shape, the actuator106shown inFIG. 22can be manufactured by cutting the actuator106, which is formed as one body, at each of actuator106. By forming a plurality of the actuator106in one body, a plurality of actuator106can be manufactured effectively at the same time, and also the handling during the transportation becomes easy.

The actuator106has a thin plate or a vibrating plate176, a base plate178, an elastic wave generating device or piezoelectric element174, a terminal forming member or an upper electrode terminal168, and a terminal forming member or a lower electrode terminal170. The piezoelectric element174includes a piezoelectric vibrating plate or a piezoelectric layer160, an upper electrode164, and a lower electrode166. The vibrating plate176is formed on the top surface of the base plate178, and the lower electrode166is formed on the top surface of the vibrating plate176. The piezoelectric layer160is formed on the top surface of the lower electrode166, and the upper electrode164is formed on the top surface of the piezoelectric layer160. Therefore, the main portion of the piezoelectric layer160is formed by sandwiching the main portion of the piezoelectric layer160by the main portion of the upper electrode164and the main portion of the lower electrode166from top side and from bottom side.

A plurality of the piezoelectric element174, four numbers in the case ofFIG. 26, is formed on the vibrating plate176. The lower electrode166is formed on the top surface of the vibrating plate176. The piezoelectric layer160is formed on the top surface of the lower electrode166, and the upper electrode164is formed on the top surface of the piezoelectric layer160. The upper electrode terminal168and the lower electrode terminal170are formed on the end portion of the upper electrode164and the lower electrode166. The four numbers of the actuator106are used separately by cutting each of the actuator106separately.

FIG. 27shows a cross-section of a part of the actuator106. The through hole178ais formed on the face of the base plate178which faces with the piezoelectric element174. The through hole178ais sealed by the vibrating plate176. The vibrating plate176is formed by the material which has electric insulating characteristic such as alumina and zirconium oxide and also possible to be deformed elastically. The piezoelectric element174is formed on the vibrating plate176to face with the through hole178a. The lower electrode166is formed on the surface of the vibrating plate176so as to be extended to the one direction, left direction inFIG. 28, from the region of the through hole178a. The upper electrode164is formed on the surface of the piezoelectric layer160so as to be extended to the opposite direction of the lower electrode166, which is right direction inFIG. 28, from the region of the through hole178a. Each of the upper electrode terminal168and the lower electrode terminal170is formed on the surface of the each of supplementary electrode172and the lower electrode166, respectively. The lower electrode terminal170with the lower electrode166electrically, and the upper electrode terminal168contacts with the upper electrode164electrically through the supplementary electrode172to deliver a signal between the piezoelectric element and the outside of the actuator106. The upper electrode terminal168and the lower electrode terminal170has 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. 29shows the manufacturing method of the actuator106shown in FIG.26. First, a through hole940ais formed on a green sheet940by perforating the green sheet940by a press or laser processing. The green sheet940becomes the base plate178after the burning process. The green sheet940is formed by the material such as ceramic material. Then, a green sheet941is laminated on the surface of the green sheet940. The green sheet941becomes the vibrating plate176after the burning process. The green sheet941is formed by the material such as zirconium oxide. Then, a conductive layer942, the piezoelectric layer160, and a conductive layer944is formed on the surface of the green sheet941sequentially by the method such as printing. The conductive layer942becomes the lower electrode166, and the conductive layer944becomes the upper electrode164after the burning process.

Next, the green sheet940, the green sheet941, the conductive layer942, the piezoelectric layer160, and the conductive layer944are dried and burned. The spacer member947and948are provided on the green sheet941to raising the height of the upper electrode terminal168and the lower electrode terminal170to be higher than the piezoelectric element. The spacer member947and948is formed by printing the same material with the green sheet940and941or by laminating the green sheet on the green sheet941. By this spacer member947and948, the quantity of the material of the upper electrode terminal168and the lower electrode terminal170, which is a noble metal, can be reduced. Moreover, because the thickness of the upper electrode terminal168and the lower electrode terminal170can be reduced, the upper electrode terminal168and the lower electrode terminal170can be accurately printed to be a stable height.

If a connection part944′, which is connected with the conductive layer944, and the spacer member947and948are formed at the same time when the conductive layer942is formed, the upper electrode terminal168and the lower electrode terminal170can be easily formed and firmly fixed. Finally, the upper electrode terminal168and the lower electrode terminal170are formed on the end region of the conductive layer942and the conductive layer944. During the forming of the upper electrode terminal168and the lower electrode terminal170, the upper electrode terminal168and the lower electrode terminal170are formed to be connected with the piezoelectric layer160electrically.

FIG. 30shows the further other embodiment of the ink cartridge of the present invention. In the ink cartridge shown inFIG. 30, ink absorbing member74is provided in the container1to face to the through hole1c, which is provided inside the container1, as a wave preventing wall. The actuator70is fixed to the bottom of the container1to face to the through hole1c.the ink absorbing member74prevents the wave or bubbles of ink inside the ink cartridge to enter into the through hole1c. The ink absorbing member thereby prevents the wave or bubbles of ink to move close to the actuator70and attach to the actuator70.

The ink absorbing member74is designed such that the hole diameter of the porous part74baround the ink supply port2is smaller than the hole diameter of the porous part74aaround the actuator70. Furthermore, the ink absorbing member74is designed such that the capillary force of the porous part74baround the ink supply port2is smaller than the capillary force in a degree which holds ink.

Thereby, if the ink absorbing member74exposes from ink by consuming of ink inside the container1, ink in the ink absorbing member74flows out from the ink absorbing member74by its own weight to the ink supply port2. If all the ink inside the container1consumed up, the ink absorbing member74absorbs the ink remained in the through hole1cby the capillary force. Therefore, ink is drained from the concave part of the through hole1c.Therefore, because the residual vibration of the actuator70changes at the ink end status, the timing of the ink end can be further reliably detected.

Therefore, the ink absorbing member74can protect the actuator70from the wave of ink and also absorbs the ink remained in the through hole1cto improve the accuracy of the ink end detection of the actuator106.

FIG. 31shows 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 hole1con the bottom face1aof the container1, which contains ink. The bottom part of the through hole1cis closed by the actuator650and forms an ink storing part. The ink absorbing member78is provided around the inside the through hole1cwhich is provided inside the container1and around the through hole1cas a wave preventing wall. The ink absorbing member78has a ink absorbing member78awhich is provided inside the through hole1cand the ink absorbing member78bwhich is provided around the through hole1c.

FIG.31(B) shows a detailed cross section of the actuator650and the through hole1cshown in FIG.31(A). FIG.31(C) shows a plan view of the actuator650and the through hole1cshown in FIG.31(B). The actuator650has a vibrating plate72and a piezoelectric element73which is fixed to the vibrating plate72. The vibrating plate72can be elastically deformed and is ink resistant. In the present embodiment, the shape of the piezoelectric element73and the through hole1cis long and narrow rectangular, and both ends of which is circular shape.

FIG. 32shows other embodiment of the through hole1c. 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 hole1c, and the right hand side of the figure shows the status that ink K is remained in the through hole1c. In the embodiment ofFIG. 31, the side face of the through hole1cis formed as the vertical wall. In FIG.32(A), the side face id of the through hole1cis slanted in vertical direction and opens with expanding to the outside. In FIG.32(B), a stepped portion1eand1fare formed on the side face of the through hole1c. The stepped portion1f, which is provided above the stepped portion1e, is wider than the stepped portion1e.In FIG.32(C), the through hole1chas a groove1gthat extends to the direction in which ink is easily discharged, that is, the direction to a ink supply port2.

A wave preventing wall, not shown in the figure, is provided in the container1such that the wave preventing wall faces to the actuator650.

According to the shape of the through hole1cshown in FIGS.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.22andFIG. 23, the vibration characteristic of the actuator650at 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 container1, 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 actuator670of the embodiment shown in FIG.33(A) is mounted. In the present embodiment, the actuator670comprises a concave part forming base plate80and a piezoelectric element82. The concave part81is formed on the one side of the face of the concave part forming base plate80by the technique such as etching, and piezoelectric element82is mounted on the other side of the face of the concave part forming base plate80. The bottom portion of the concave part81operates as a vibrating region within the concave part forming base plate80. Therefore, the vibrating region of the actuator670is determined by the periphery of the concave part81. Furthermore, the actuator670has the similar structure with the structure of the actuator106shown inFIG. 22, in which the base plate178and the vibrating plate176is 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 actuator670has a size which can be embedded into the through hole1cprovided on the container1. By this embedding process, the concave part81can operates as the cavity. The actuator106shown inFIG. 22can be formed to be embedded into through hole1cas actuator670shown in FIG.33. Moreover, the wave preventing wall1192uis provided nearby the concave part81in the container1such that the wave preventing wall1192ufaces to the actuator670.

FIG. 34shows a slant view of the other embodiment of the actuator. The actuator660has packing76on the outside of the base plate, which constitutes the actuator660, or the through hole1cof a mounting plate72. Caulking holes77are formed on the outskirts of the actuator660. The actuator660is fixed to the container1through the caulking hole77with caulking.

Furthermore, also in the present embodiment, the wave preventing wall, not shown in the figure, can be provided nearby the packing76such that the wave preventing wall faces to the actuator670as 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 packing76. If the wave preventing wall is the member which pass through ink, the actuator660can detects ink. In this case, the wave preventing wall1192uis mounted on the ink cartridge together with the actuator670as 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,35B and35C show plan views of the through hole1caccording to another embodiment. As shown respectively inFIGS. 35A,35B and35C, the plane shape of the through hole1cmay 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. 36shows a slant view of the configuration that forms the actuator106in one body as a mounting module100. The module100is mounted on the predetermined position of the container1of an ink cartridge. The module100is constituted to detect the ink consumption status in the container1by detecting at least the change of acoustic impedance of the ink liquid. The module100of the present embodiment has a liquid container mounting member101for mounting the actuator106to the container1. The liquid container mounting member101has a structure which mounts a cylindrical part116that contains the actuator106which oscillates by the driving signal on a base mount102, the plan of which is substantially rectangular. Because the module100is constructed so that the actuator106of the module100can not be contact from outside when the module100is mounted on the ink cartridge, the actuator106can be protected from outside contact. The top side of the edge of the cylindrical part116is chamfered so that the cylindrical part116can be easily fit into the hole which is formed in the ink cartridge.

FIG. 37shows an exploded view of the module100shown inFIG. 36to show the structure of the module100. The module100includes a liquid container mounting member101made from a resin and a piezoelectric device mounting member105which has a plate110and a concave part113. Furthermore, the module100has a lead wire104aand104b, actuator106, and a film108. Preferably, the plate110is made from a material which is difficult to be rust such as stainless or stainless alloy. The opening114is formed on the central part of the cylindrical part116and the base mount102which are included in the liquid container mounting member101so that the cylindrical part116and the base mount102can contain the lead wire104aand104b. The concave part113is formed on the central part of the cylindrical part116and the base mount102so that the cylindrical part116and the base mount102can contain the actuator106, the film108, and the plate110. The actuator106is connected to the plate110through the film108, and the plate110and the actuator106are fixed to the liquid container mounting member101. Therefore, the lead wire104aand104b, the actuator106, the film108and the plate110are mounted on the liquid container mounting member101as one body. Each of the lead wire104aand104btransfer a driving signal to piezoelectric layer by coupling with the upper electrode and the lower electrode166of the actuator106, and also transfer the signal of resonant frequency detected by the actuator106to recording apparatus. The actuator106oscillates temporally based on the driving signal transferred from the lead wire104aand104b. The actuator106vibrates residually after the oscillation and generates a counter electromotive force by the residual vibration. By detecting the vibrating period of the wave form of the counter electromotive force, the resonant frequency corresponding to the consumption status of the liquid in the liquid container can be detected. The film108bonds the actuator106and the plate110to seal the actuator106. The film108is preferably formed by such as polyolefin and bonded to the actuator106and the plate110by heat sealing. By bonding the actuator106and the plate110with the film108face 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 actuator106to plate110is small.

The plate110is circular shape, and the opening114of the base mount102is formed in cylindrical shape. The actuator106and the film108are formed in rectangular shape. The lead wire104, the actuator106, the film108, and the plate110can be attached to and removed from the base mount102. Each of the base mount102, the lead wire104, the actuator106, the film108, and the plate110is arranged symmetric with respect to the central axis of the module100. Furthermore, each of the centers of the base mount102, the actuator106, the film108, and the plate110is arranged substantially on the central axis of the module100.

The opening114of the base mount102is formed such that the area of the opening114is larger than the area of the vibrating region of the actuator106. The through hole112is formed on the center of the plate110where the vibrating section of the actuator106faces. As shown in FIG.22andFIG. 23, the cavity162is formed on the actuator106, and both of the through hole112and the cavity162forms ink storing part. The thickness of the plate110is preferably smaller than diameter of the through hole112to reduce the influence of the residual ink. For example, the depth of the through hole112is preferably smaller than one third of the diameter of the through hole112. The shape of the through hole112is substantially true circle and symmetric with respect to the central axis of the module100. Furthermore, the area of the through hole112is larger than the area of opening of the cavity162of the actuator106. The periphery of the shape of the cross-section of the through hole112can be tapered shape of stepped shape. The module100is mounted on the side, top, or bottom of the container1such that the through hole112faces to the inside of the container1. When the ink is consumed, and the ink around the actuator106is exhausted, the resonant frequency of the actuator106greatly changes. The change of the ink level can thus be detected.

FIG. 38shows the slant view of the other embodiments of the module. The piezoelectric device mounting member405is formed on the liquid container mounting member101in the module400of the present embodiment. The cylindrical part403, which has a cylindrical shape, is formed on the base mount102, which has a square shaped plan, the edges of which are rounded, in the liquid container mounting member401. Furthermore, the piezoelectric apparatus mounting member405includes a board shaped element405, which is set up on the cylindrical part403, and a concave part413. The actuator106is arranged on the concave part413provided on the side face of the board shaped element406. The top end of the board shaped element406is chamfered in predetermined angle so that the board shaped element is easy to fit into hole formed on the ink cartridge when mounting the actuator106to ink cartridge.

FIG. 39shows an exploded view of the module400shown inFIG. 38to show the structure of the module400. As the module100shown inFIG. 36, the module400includes a liquid container mounting member401and a piezoelectric device mounting member405. The liquid container mounting member401has the base mount402and the cylindrical part403, and the piezoelectric device mounting member405has the board shaped element406and the concave part413. The actuator106is connected to the plate410and fixed to the concave part413. The module400has a lead wire404aand404b, actuator106, and a film408.

According to the present embodiment, the plate410is rectangular shape, and the opening414provided on the board shaped element406is formed in rectangular shape. The lead wire404aand404b, the actuator106, the film408, and the plate410can be attached to and removed from the base mount402. Each of the actuator106, the film408, and the plate410is arranged symmetric with respect to the central axis which is extended to perpendicular direction to the plan of opening414and also pass through the center of opening414. Furthermore, each of the centers of the actuator106, the film408, and the plate410is arranged substantially on the central axis of the opening414.

The through hole412provided on the center of the plate410is formed such that the area of the through hole412is larger than the area of the opening of the cavity162of the actuator106. The cavity162of the actuator106and the through hole412together forms ink storing part. The thickness of the plate410is preferably smaller than diameter of the through hole412. For example, the thickness of the plate410is smaller than one third of the diameter of the through hole412. The shape of the through hole412is substantially true circle and symmetric with respect to the central axis of the module400. The shape of the cross-section of the periphery of the through hole112can be tapered shape or stepped shape. The module400can be mounted on the bottom of the container1such that the through hole412is arranged inside of the container1. Because the actuator106is arranged inside the container1such that the actuator106extends 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 actuator106in the container1by changing the height of the base mount402.

FIG. 40shows the further other embodiment of the module. As the module100shown inFIG. 36, the module500ofFIG. 40includes a liquid container mounting member501which has a base mount502and a cylindrical part503. Furthermore, the module500further has a lead wire504aand504b, actuator106, a film508, and a plate510. The opening514is formed on the center of the base mount502, which is included in the liquid container mounting member501, so that the base mount502can contain the lead wire504aand504b. The concave part513is formed on the cylindrical part503so that the cylindrical part503can contain the actuator106, the film508, and the plate510. The actuator106is fixed to the piezoelectric device mounting member505through the plate510. Therefore, the lead wire504aand504b, the actuator106, the film508, and the plate510are mounted on the liquid container mounting member501as one body. The cylindrical part503, 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 actuator106is arranged on the concave part513which is provided on the top surface of the cylindrical part503that is slanted in vertical direction.

The top end of the module500is slanted, and the actuator106is mounted on this slanted surface. Therefore, if the module500is mounted on the bottom or the side of the container1, the actuator106slants in the vertical direction of the container1. The slanting angle of the top end of the module500is substantially between 30 degree and 60 degree with considering the detecting performance.

The module500is mounted on the bottom or the side of the container1so that the actuator106can be arranged inside the container1. When the module500is mounted on the side of the container1, the actuator106is mounted on the container1such that the actuator106faces the upside, downside, or side of the container1with slanting. When the module500is mounted on the bottom of the container1, the actuator106is preferable to be mounted on the container1such that the actuator106faces to the ink supply port side of the container1with slanting.

FIG. 41shows a cross-sectional view around the bottom of the container1when the module100shown inFIG. 36is mounted on the container1. The module100is mounted on the container1so that the module100penetrates through the side wall of the container1. The O-ring365is provided on the connection face of between the side wall of the container1and the module100to seal between the module100and the container1. The module100is preferable to include the cylindrical part as explained inFIG. 36so that the module100can be sealed by the O-ring. By inserting the top end of the module100inside the container1, ink in the container1contacts with the actuator106through the through hole112of the plate110. Because the resonant frequency of the residual vibration of the actuator106is different depends on whether the circumference of the vibrating section of the actuator106is liquid or gas, the ink consumption status can be detected using the module100. Furthermore, not only the module100can be mounted on the container1and detect the existence of ink, but also the module400shown inFIG. 38, module500shown inFIG. 40, or the module700A and700B shown inFIG. 42, and a mold structure600can be mounted on the container1and detect the existence of the ink.

FIG.42(A) shows the cross section of the ink container when mounting module700B on the container1. The present embodiment uses a module700B as an example of amounting structure. The module700B is mounted on the container1such that the liquid container mounting member360protrude into the inside of the A through hole370is formed in the mounting plate350, and the through hole370faces to the vibrating section of the actuator106. Furthermore, a hole382is formed on the bottom wall of the module700B, and a piezoelectric device mounting member363is formed. The actuator106is arranged to close the one of the face of the hole382. Therefore, ink contacts with the vibrating plate176through the hole382of the piezoelectric device mounting member363and the through hole370of the mounting plate350. The hole382of the piezoelectric device mounting member363and the through hole370of the mounting plate350together forms an ink storing part. The piezoelectric device mounting member363and the actuator106are fixed by the mounting plate350and the film material. The sealing structure372is provided on the connection part of the liquid container mounting member360and the container1. The sealing structure372can be formed by the plastic material such as synthetic resin or O-ring. In FIG.42(A), the module700B and the container1is separate body, however, the piezoelectric device mounting member can be constituted by a part of the container1as shown in FIG.42(B).

The module700B shown inFIG. 42does not need to embed the lead wire into the module as shown inFIG. 36to FIG.40. Therefore, the forming process becomes simple. Also, the exchange of the module700B becomes possible so that the recycling of the module700B also becomes possible.

There is possibility that the actuator106malfunctions by the contact of the ink which is dropped from a top face or a side face of the container1with the actuator106, the ink of which is attached to the top face or the side face of the container1when the ink cartridge is shaken. However, because the liquid container mounting member360of the module700B protrudes into the inside of the container1, the actuator106does not malfunction by the ink dropped from the top face or the side face of the container1.

Furthermore, the module700B is mounted on the container1so that only part of the vibrating plate176and the mounting plate350are contact with ink inside of the container1in the embodiment of FIG.42(A). The embedding of the electrode of the lead wire104a,104b,404a,404b,504a, and504shown inFIG. 36toFIG. 40into the module becomes unnecessary for the embodiment shown in FIG.42(A). Therefore, the forming process becomes simple. Also, the exchange of the actuator106becomes possible so that the recycling of the actuator106also becomes possible.

FIG.42(B) shows the cross section of the ink container when mounting actuator106on the container1. A protecting member361is mounted on the container separately with the actuator106in the ink cartridge of the embodiment shown in FIG.42(B). Therefore, the protecting member361and the actuator106is not one body as a module, and the protecting member361thus can protect the actuator106not to be contact by the user. A hole380which is provide on the front face of the actuator106is arranged on the side wall of the container1. The actuator106includes the piezoelectric layer160, the upper electrode164, the lower electrode166, the vibrating plate176, and the mounting plate350. The vibrating plate176is formed on the mounting plate350, and the lower electrode166is formed on the vibrating plate176. The piezoelectric layer160is formed on the top face of the lower electrode166, and the upper electrode164is formed on the top face of the piezoelectric layer160.

Therefore, the main portion of the piezoelectric layer160is formed by sandwiching the main portion of the piezoelectric layer160by the main portion of the upper electrode164and the lower electrode166from top and bottom. The circular portion, which is a main portion of each of the piezoelectric layer160, the upper electrode164, and the lower electrode166, forms a piezoelectric element. The piezoelectric element is formed on the vibrating plate176. The vibrating region of the piezoelectric element and the vibrating plate176constitutes the vibrating section, on which the actuator106actuary vibrates. A through hole370is provided on the mounting plate350. Furthermore, a hole380is formed on the side wall of the container1.

Therefore, ink contacts with the vibrating plate176through the hole380of the container1and the through hole370of the mounting plate350. The hole380of the container land the through hole370of the mounting plate350together forms ink storing part.

Moreover, because the actuator106is protected by the protecting member361, the actuator106can be protected form the outside contact. The base plate178shown inFIG. 22can be used instead of the mounting plate350in the embodiment shown in FIGS.42(A) and (B).

FIG.42(C) shows an embodiment that comprises a mold structure600which includes the actuator106. In the present embodiment, a mold structure600is used as one example of the mounting structure. The mold structure600has the actuator106and a mold member364. The actuator106and the mold member364are formed in one body. The mold member364is formed by a plastic material such as silicon resin. The mold member364includes a lead wire362in its inside. The mold member364is formed so that the mold member364has two legs extended from the actuator106. The end of the two legs of the mold member364are formed in a shape of hemisphere to liquid tightly fix the mold member364with container1. The mold member364is mounted on the container1such that the actuator106protrudes into the inside of the container1, and the vibrating section of the actuator106contacts with ink inside the container1. The upper electrode164, the piezoelectric layer160, and the lower electrode166of the actuator106are protected from ink by the mold member364.

Because the mold structure600shown inFIG. 42does not need the sealing structure372between the mold member364and the container1, the leaking of ink from the container1can be reduced. Moreover, because the mold structure600has a form that the mold structure600does not protrude from the outside of the container1, the mold structure600can protect the actuator106from the outside contact. There is possibility that the actuator106malfunctions by the contact of the ink which is dropped from a top face or a side face of the container1with the actuator106, the ink of which is attached to the top face or the side face of the container1when the ink cartridge is shaken. Because the mold member364of the mold structure600protrudes into the inside of the container1, the actuator106does not malfunction by the ink dropped from the top face or the side face of the container1.

FIG. 43shows an embodiment of an ink cartridge and an ink jet recording apparatus which uses the actuator106shown inFIG. 22. Aplurality of ink cartridges180is mounted on the ink jet recording apparatus which has a plurality of ink introducing members182and a holder184each corresponding to the each of ink cartridge180, respectively. Each of the plurality of ink cartridges180contains different types of ink, for example, different color of ink. The actuator106, which detects at least acoustic impedance, is mounted on the each of bottom of the plurality of ink cartridge180. The residual quantity of ink in the ink cartridge180can be detected by mounting the actuator106on the ink cartridge180.

Furthermore, the wave preventing wall, not shown in the figure, is provided inside the ink cartridge180such that the wave preventing wall faces to the actuator106.

FIG. 44shows a detail around the head member of the ink jet recording apparatus. The ink jet recording apparatus has an ink introducing member182, a holder184, a head plate186, and a nozzle plate188. A plurality of nozzle190, which jet out ink, is formed on the nozzle plate188. The ink introducing member182has an air supply hole181and an ink introducing inlet183. The air supply hole181supplies air to the ink cartridge180. The ink introducing inlet183introduces ink from the ink cartridge180. The ink cartridge180has an air introducing inlet185and an ink supply port187. The air introducing inlet185introduces air from the air supply hole181of the ink introducing member182. The ink supply port187supplies ink to the ink introducing inlet183of the ink introducing member182. By introducing air from the ink introducing member182to the ink cartridge180, the ink cartridge180accelerates the supply of ink from the ink cartridge180to the ink introducing member182.

Furthermore, the wave preventing wall, not shown in the figure, is provided inside the ink cartridge180such that the wave preventing wall f aces to the actuator106.

FIG. 45shows other embodiment of the ink cartridge180shown in FIG.44. The actuator106is mounted on the bottom face194a, which is formed to be slanted in vertical direction, of the ink cartridge180A shown in the FIG.45(A). A wave preventing wall1192vis provided on the position where has the predetermined height from the bottom face of the inside the container194and also faces to the actuator106inside the container194of the ink cartridge180. Because the actuator106is mounted on the container194slanted in vertical direction, the drainage of ink can be improved.

A gap, which is filled with ink, is formed between the actuator106and the wave preventing wall1192v. The gap between the wave preventing wall1192vand the actuator106does not hold ink by capillary force. When the container194is rolled, ink wave is generated inside the container194by the waving, and there is possibility that the actuator106malfunctions by detecting gas or an air bubble caused by the shock of the ink wave. By providing the wave preventing wall1192v, ink wave around the actuator106can be prevented so that the malfunction of the actuator106can be prevented.

The actuator106of the ink cartridge180B shown in FIG.45(B) is mounted on the side wall of the supply port of the container194. The actuator106can be mounted on the side wall or bottom face of the container194if the actuator106is mounted nearby the ink supply port187. The wave preventing wall1192W is provided nearby the ink supply port187inside the container194such that the wave preventing wall1192W faces to the actuator106. The wave preventing wall1192wis formed in L-shape to effectively prevent the wave of ink. Moreover, the actuator106is preferably mounted on the center of the width direction of the container194. Because ink is supplied to the outside through the ink supply port187, ink and actuator106reliably contacts until the timing of the ink near end by providing the actuator106nearby the ink supply port187. Therefore, the actuator106can reliably detect the timing of the ink near end.

Furthermore, by providing the actuator106nearby the ink supply port187, the setting position of the actuator106to 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 actuator106becomes reliable by arranging the actuator nearby the ink supply port. Furthermore, the actuator106can be further reliably positioned by mounting the actuator106at the center of the width direction of the container194. 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. 46shows further other embodiment of the ink cartridge180. FIG.46(A) shows a cross section of an ink cartridge180C, and FIG.46(B) shows a cross section which enlarges the side wall194bof an ink cartridge180C shown in FIG.46(A). FIG.46(C) shows perspective view from the front of the side wall194bof the ink cartridge180C. The semiconductor memory device7and the actuator106are formed on the same circuit board610in the ink cartridge180C. As shown in FIG.46(A), the wave preventing all1192xis provided inside the container194such that the wave preventing wall1192xfaces to the actuator700. As shown in FIGS.46(B) and (C), the semiconductor memory device7is formed on the upper side of the circuit board610, and the actuator106is formed on the lower side of the semiconductor memory device7on the same circuit board610. A different-type O-ring614is mounted on the side wall194bsuch that the different-type O-ring614surrounds the actuator106. A plurality of caulking part616is formed on the side wall194bto couple the circuit board610with the container194. By coupling the circuit board610with the container194using the caulking part616and pushing the different-type O-ring614to the circuit board610, the vibrating region of the actuator106can contacts with ink, and at the same time, the inside of the ink cartridge is sealed from outside of the ink cartridge.

A terminals612are formed on the semiconductor memory device7and around the semiconductor memory device7. The terminal612transfer the signal between the semiconductor memory device7and outside the inkjet recording apparatus. The semiconductor memory device7can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device7and the actuator106are formed on the same circuit board610, the mounting process can be finished at one time during mounting the semiconductor memory device7and the actuator106on the ink cartridge180C. Moreover, the working process during the manufacturing of the ink cartridge180C and the recycling of the ink cartridge180C can be simplified. Furthermore, the manufacturing cost of the ink cartridge180C can be reduced because the numbers of the parts can be reduced.

The actuator106detects the ink consumption status inside the container194. The semiconductor memory device7stores the information of ink such as residual quantity of ink detected by the actuator106. That is, the semiconductor memory device7stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator106when detecting the ink consumption status. The semiconductor memory device7previously stores the resonant frequency of when ink inside the container194is full, that is, when ink is filled in the container194sufficiently, or when ink in the container194is end, that is, ink in the container194is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container194is 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 container194is full status or end status can be stored during the manufacturing of the container194. 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 container194is full status or end status in the semiconductor memory device7previously 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. 47shows further other embodiment of the ink cartridge180. The ink cartridge180E shown in FIG.47(A) mounts a actuator606which is long in vertical direction on the side wall194bof the container194. The wave preventing wall1192xis provided inside the container194such that the wave preventing wall1192xfaces to the whole of the vibrating region of the actuator106. The change of the residual quantity of ink inside the container194can be detected continuously by the actuator606which is long in vertical direction. The length of the actuator606is preferably longer than the half of the height of the side wall194b. In FIG.47(A), the actuator606has the length from the substantially from the top end to the bottom end of the side wall194b. Therefore, the wave preventing wall1192xalso has a length substantially from the top end to the bottom end of the sidewall194b. By providing the wave preventing wall1192x, the wave preventing wall1192xprevents the wave of ink around the actuator606and prevents the malefaction of the actuator606. Furthermore, the wave preventing wall1192xprevents the bubble generated by the waving of ink to enter to the actuator606.

The ink cartridge180F shown in FIG.47(B) mounts a plurality of actuators106on the side wall194bof the container194and comprises a wave preventing wall1192xon the face of the plurality of actuators606. The ink cartridge180F further comprises the wave preventing wall1192x, which is long in vertical direction, along the side wall194bwith predetermined gap with the side wall194binside the container194. A gap which is filled with ink is formed between the actuator106and the wave preventing wall1192x. Moreover, the gap between the wave preventing wall1192xand the actuator106has a enough distance such that the gap does not hold ink by capillary force. When the container194is rolled, ink wave is generated inside the container194by the waving, and there is possibility that the actuator106malfunctions 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 wall1192x, ink wave around the actuator106can be prevented so that the malfunction of the actuator106can be prevented. The wave preventing wall1192xalso prevents the air bubble generated by the waving of ink to enter to the actuator106.

FIG. 48shows further other embodiment of the ink cartridge180. The ink cartridge180G shown in FIG.48(A) has a top wall1080and a bottom wall1090, each of which is located on the upside and downside of the ink surface inside the container194. A plurality of wave preventing walls212aare extended from the top wall1080downward to the bottom wall1090. Because each of lower end of the partition walls212and the bottom face of the container194has a predetermined gap, the bottom part of the container194communicates with each other. The ink cartridge180G has a plurality of containing chambers213divided by the each of plurality of partition walls212. The bottom part of the plurality of the containing chambers213communicates with each other. The actuator106is mounted on the side wall1070which faces to the ink supply port187. The actuator106is arranged on substantially center of the top face194cof the containing chamber213of the container194. The volume of the containing chamber213is arranged such that the volume of the containing chamber213of the ink supply port187is the largest, and the volume of the containing chamber213gradually decreases as the distance from the ink supply port187increases to the inner part of the ink cartridge180G. Therefore, the containing chamber213becomes wider towards from the actuator106mounting side of the containing chamber213to the ink supply port187side of the containing chamber213.

Because ink is drained from the ink supply port187, and air enters from the air introducing inlet185, ink is consumed from the containing chamber213of the ink supply port187side to the containing chamber213of the inner part of the ink cartridge180G. For example, the ink in the containing chamber213which is most near to the ink supply port187is consumed, and during the ink level of the containing chamber213which is most near to the ink supply port187decreases, the other containing chamber213are filled with ink. When the ink in the containing chamber213which is most near to the ink supply port187is consumed totally, air enters to the containing chamber213which is second by counted from the ink supply port187, then the ink in the second containing chamber213is beginning to be consumed so that the ink level of the second containing chamber213begin to decrease. At this time, ink is filled in the containing chamber213which is third or more than third by counted from the ink supply port187. In this way, ink is consumed from the containing chamber213which is most near to the ink supply port187to the containing chamber213which is far from the ink supply port187in order.

As shown above, because the actuator106is arranged on the containing chamber213that is farthermost from the ink supply port187, the actuator106can detect the ink end. Furthermore, the plurality of wave preventing walls212acan effectively prevent the waves of ink.

The ink cartridge180H shown in FIG.48(B) has a top wall1080and a bottom wall1090, each of which is located on the upside and downside of the ink surface inside the container194. A plurality of wave preventing walls212bare extended from the top wall1080and the bottom wall1090alternately. There are gap between the partition wall212b, which extends from the bottom wall1090, among the plurality of the wave preventing wall212band the side wall, not shown in the figure, located on width direction of the container194. Therefore, the level of ink surface in each containing chamber213is equal.

Furthermore, among the plurality of wave preventing wall212b, the wave preventing wall212bwhich extends from the top wall1090and the side wall, not shown in the figure, located on width direction of the container194can be coupled liquid-tightly or air-tightly. In case the wave preventing wall212bwhich is nearest to the actuator106among the plurality of wave preventing wall212bextends from the top wall1080, gas enters to the containing chamber213which is nearest to the actuator106when the level of ink surface inside the container194reaches to the lower end of the wave preventing wall212bwhich is nearest to the actuator106. Therefore, the level of ink surface for detecting the ink end is determined by the position of the lower end212fto the level of ink surface along a vertical direction

In the ink cartridge180I shown in FIG.48(C), the actuator106is mounted on the side wall1070around the boundary of the side wall1070and the top wall1080. The ink cartridge180I includes at least two containing chambers of containing chamber213aand containing chamber213bwhich are partitioned by the wave preventing wall212c. Among two containing chambers, a negative pressure generating member1100which generates a negative pressure is provided on the supply port side containing chamber213awhich is relatively near to the ink supply port187. Among two containing chambers, the actuator106is provided on the inner side containing chamber213bwhich is relatively far from the ink supply port187.

A buffer214is formed on the top wall1080of the containing chamber213b. The buffer214is a concave part which accepts the bubble which enters into the ink cartridge180I when the ink cartridge180I is manufactured or when the ink cartridge180I is left for a long period without to be used. In FIG.48(C), the buffer214is formed as a concave part which overhangs from the side wall194bof the container194. Because the negative pressure generating member1100and the buffer214accepts the bubbles enters inside the containing chamber213b, the negative pressure generating member1100and the buffer214can prevent the malfunction of the actuator106such as detecting the ink end by the attaching of bubbles on the actuator106. Furthermore, the ink quantity which can be consumed after detecting the ink end can be changed by changing the capacity of containing chamber213band the length of the wave preventing wall212c.

In the ink cartridge180J shown in FIG.48(D), a plurality of wave preventing walls212dare extended from the side wall1070and the side wall1110of the container194alternately. Furthermore, each of one end212ddof each of the wave preventing wall212dis 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 walls212dand the side wall, not shown in the figure, which intervene between the side wall1070of the container194and the side wall1110. Therefore, ink does not remain on the wave preventing wall212d. A plurality of actuators106are mounted on the side wall1070which extends substantially vertically to ink surface among the wall of container194. A plurality of actuators106is mounted on the different height to the ink surface with each other. Thereby the actuator106can detect the ink consumption status step by step. In the present embodiment, the buffer214is provided around the side wall1070of the actuator106mounting side among the top wall1080.

FIG. 49shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. In the ink cartridge180K of the present embodiment, the actuator106is mounted on the side wall1070which faces to the ink supply port187. Each of a plurality of wave preventing wall212eextends from the first side wall1120aand the second side wall1120b, which intervene between side wall1070and the side face where the ink supply port187is provided, alternatively. By the plurality of wave preventing wall212ewhich extends from the side wall1120aand the1120b, the actuator106is effectively protected from the wave of ink and the generation of the bubbles is suppressed.

FIG. 50shows a plan cross sectional view of the further another embodiment of the ink cartridge according to the present invention. In the ink cartridge180L of the present embodiment, the actuator106is mounted on the side wall1070which faces to the ink supply port187. The wave preventing wall212gincludes a bending part800, at least a part of the end of the wave preventing wall of which is bent toward the side wall1070where the actuator106is mounted. A capillary force does not work between the wave preventing wall212gand the actuator106. Furthermore, a gap, on which a capillary force works, is provided between the bending part800and the side wall1070. Therefore, the entering of the bubbles between the actuator106and the wave preventing wall212gcan be prevented. The ink level around the actuator106is equal to the other ink level in the ink cartridge180L. Therefore, the actuator106can accurately detect the ink consumption status inside the ink cartridge180L.

FIG. 51shows other embodiment of the ink cartridge using the actuator106. The ink cartridge220A shown in FIG.51(A) has a first wave preventing wall222provided such that it extends from the top wall1081, which locates upside of the ink surface, downward to the ink surface among the wall of the ink cartridge220A. Because there is a predetermined gap between the lower end of the first wave preventing wall222and the bottom wall1091of the ink cartridge220A, ink can flows into the ink supply port230through the bottom face of the ink cartridge220A. A second wave preventing wall224is formed such that the second wave preventing wall224extends upward from the bottom face of the ink cartridge220A on the ink supply port230side of the first wave preventing wall222. Because there is a predetermined gap between the upper end of the second wave preventing wall224and the top face of the ink cartridge220A, ink can flows into the ink supply port230through the top face of the ink cartridge220A.

A ventilation side ink chamber225ais formed on the inner part of the first wave preventing wall222, seen from the ink supply port230, by the first wave preventing wall222. On the other hand, a detection side ink chamber225bis formed on the front side of the second wave preventing wall224, seen from the ink supply port230, by the second wave preventing wall224. The volume of the ventilation side ink chamber225ais larger than the volume of the detection side ink chamber225b. A detection side small ink chamber227is formed by providing a gap, which can generate he capillary phenomenon, between the first wave preventing wall222and the second wave preventing wall224. Therefore, the ink in the ventilation side ink chamber225ais collected to the detection side small ink chamber227by the capillary force of the detection side small ink chamber227. Therefore, the detection side small ink chamber227can prevent that the air or air bubble enters into the detection side ink chamber225b. Furthermore, the ink level in the detection side ink chamber225bcan decrease steadily and gradually. Because the ventilation side ink chamber225ais formed at more inner part of the detection side ink chamber225b, seen from the ink supply port230, the ink in the detection side ink chamber225bis consumed after the ink in the ventilation side ink chamber225ais consumed.

The actuator106is mounted on the side wall1071of the ink cartridge220A of the ink supply port230side, that is, the side wall1071of the detection side ink chamber225bof the ink supply port230side. The actuator106detects the ink consumption status inside the detection side ink chamber225b. The residual quantity of ink at the timing closed to the ink near end can be detected stably by mounting the actuator106on the side wall1071of the detection side ink chamber225b. Furthermore, by changing the height of the mounting position of the actuator106on the side wall1071of the detection side ink chamber225b, 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 chamber225ato the detection side ink chamber225bby the detection side small ink chamber227, the actuator106does not influenced by the waving of ink caused by the waving of the ink cartridge220A, and actuator106can thus reliably measure the ink residual quantity. Furthermore, because the detection side small ink chamber227holds ink, the detection side small ink chamber227can prevent ink to flow backward from the detection side ink chamber225bto the ventilation side ink chamber225a.

A check valve228is provided on the top face of the ink cartridge220A. The leaking of ink outside of the ink cartridge220A caused by the waving of the ink cartridge220A can be prevented by the check valve228. Furthermore, the evaporation of ink from the ink cartridge220A can be prevented by providing the check valve228on the top face of the ink cartridge220A. If ink in the ink cartridge220A is consumed, and negative pressure inside the ink cartridge220A exceeds the pressure of the check valve228, the check valve228opens and introduces air into the ink cartridge220A. Then the check valve228closes to maintain the pressure inside the ink cartridge220A to be stable.

FIGS.51(C) and (D) shows a detailed cross-section of the check valve228. The check valve228shown in FIG.51(C) has a valve232which includes flange232aformed by rubber. An airhole233, which communicates air between inside and outside of the ink cartridge220, is provided on the ink cartridge220such that the airhole233faces to the flange232a. The airhole233is opened and closed by the flange232a. The check valve228opens the flange232ainward the ink cartridge220when the negative pressure in the ink cartridge220exceeds the pressure of the check valve228by the decrease of ink inside the ink cartridge220A, and thus the air outside the ink cartridge220is introduced into the ink cartridge220. The check valve228shown in FIG.51(D) has a valve232formed by rubber and a spring235. If the negative pressure inside the ink cartridge220exceeds the pressure of the check valve228, the valve232presses and opens the spring235to introduce the outside air into the ink cartridge220and then closes to maintain the negative pressure inside the ink cartridge220to be stable.

The ink cartridge220B shown in FIG.51(B) has a porous member242in the ventilation side ink chamber225ainstead of providing the check valve228on the ink cartridge220A as shown in FIG.51(A). The porous member242holds the ink inside the ink cartridge220B and also prevents ink to be leaked outside of the ink cartridge220B during the waving of the ink cartridge220B.

FIG. 52is a cross sectional view of an embodiment of an ink care 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 inFIG. 52is 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 actuator106is used for an embodiment of the liquid censor that detects liquid. The ink cartridge of the embodiment shown inFIG. 52comprises a container1which contains liquid K and includes top wall1030located upside of the liquid surface of ink K, an ink supply port2which supplies liquid K outside the container1, an actuator106which detects ink consumption status inside the container1, and a first partition wall193awhich partitions at least two ink chamber such that ink K in both of the ink chamber can communicate with each other inside the container1. At least two ink chambers include a ventilation side ink chamber123awhich communicate with atmosphere and the detecting side ink chamber123b. The actuator106is mounted on the top wall1030of the ink chamber123b.

The airhole233is provided on the top wall1030of the ventilation side ink chamber123awhich ventilates with atmosphere. The check valve228shown inFIG. 56can be used for airhole233. However, the form of the airhole233is not limited to the check valve228shown in FIG.56. If ink K is consumed and the container1inside becomes extremely negative pressure, air is introduced to the ventilation side ink chamber123afrom the outside of the container1by the airhole233, and the airhole233thus prevents the pressure inside the container1to be negative. Therefore, with the consumption of ink advanced, air is introduced to the ventilation side ink chamber123athrough the airhole233, and the level of liquid surface of ink K decreases.

The partition wall193ais coupled with the top wall1030liquid-tightly. Therefore, even the ink is consumed, ink K is filled in the detection side ink chamber123bin the container1until the level of liquid surface of ink K reaches to the lower end193aaof the partition wall193a. When the ink consumption advances and the level of liquid surface of ink K reaches to the lower end193aaof the partition wall193a, gas enters to the detection side ink chamber123b. Thereby the ink k remained in the detection side ink chamber123bflows out to the ink supply port2, and the medium existed around the actuator106changes from ink K to atmosphere. Therefore, the actuator106can detect that the status inside the ink cartridge is in ink end status. Thus, it is the lower end193aato determine which level of the liquid surface of ink K to be a ink end. Furthermore, the volume of the detection side ink chamber132bis determined by the width between the side wall1010, which extends substantially vertical to the ink surface, and the partition wall193a. Therefore, the ink quantity remains inside the container1when detecting the ink end can be set by the width between the side wall1010and the partition wall193aand the height of the lower end193aain the direction vertical to the ink surface.

The volume of the detection side ink chamber123bis preferably half or smaller than half of the volume of the ventilation side ink chamber123a. A capillary force such as to hold ink K does not work on the detection side ink chamber123b.

The actuator106can 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 ring4and a valve body6are provided in the ink supply port2. Referring toFIG. 54, the packing ring4is engaged with the ink supply needle32communicating with a recording head31, in a fluid-tight manner. The valve body6is constantly and elastically contacted against the packing ring4by way of a spring5. When the ink supply needle32is inserted, the valve body6is pressed by the ink supply needle32so as to open an ink passage, so that ink inside the container1is supplied to the recording head31via the ink supply port2and the ink supply needle32. On an upper wall of the container1, there is mounted a semiconductor memory means7which stores data on ink inside the ink cartridge.

If there is no partition wall193ain the container1, 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 actuator106may detect mistakenly that there is enough ink in the container1if the ink attaches to the actuator106by the waving of ink even if there is little amount of ink in the container1. Moreover, there is also a danger that the actuator106may detect mistakenly that there is no ink if the bubble attaches to the actuator106even if the ink is filled in the container1.

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 wall193aprevents 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 actuator106and contact with the actuator106.

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. 53is a perspective view of the ink cartridge which stores plural types of inks, viewed from an outside thereof, according to an embodiment.FIG. 53is a perspective view from the side of the top wall1038which is located upside of the liquid surface of ink K among the wall of the container8. A container8is divided into three ink chambers9,10and11. Ink supply ports12,13and14are formed for the respective ink chambers. On a top wall1038of the respective ink chambers9,10and11, the respective actuators15,16and17are mounted on the container8so that the actuators15,16, and17can contact with the ink which is housed in each ink chambers via the through hole, not shown in the figure, provided on the container8. Partition walls, not shown in the figure, is provided each of inside of the ink container9,10and11as similar to the ink cartridge shown in FIG.52. The partition walls provided in each of ink chambers9,10, and11separates the each ink chambers9,10, and11into ventilation side ink chamber and detection side ink chamber.

FIG. 54is 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.52andFIG. 53. Acarriage30capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit33, while the recording head31is provided in a lower face of the subtank unit33. Moreover, the ink supply needle32is provided in an ink cartridge mounting face side of the subtank unit33. InFIG. 54, the ink cartridge shown in FIG.52andFIG. 53are used. However, the ink cartridge shown in other figures also can be used.

When the ink supply port2of the container1is inserted through the ink supply needle32of the subtank unit33, the valve body6recedes against the spring5, so that an ink passage is formed and the ink inside the container1flows into the ink chamber34. At a stage where the ink chamber34is filled with ink, a negative pressure is applied to a nozzle opening of the recording head31so as to fill the recording head with ink. Thereafter, the recording operation is performed.

When the ink is consumed in the recording head31by the recording operation, a pressure in the downstream of the flexible valve36decreases. Then, the flexible valve36is positioned away from a valve body38so as to become opened. When the flexible valve36is opened, the ink in the ink chamber34flows into the recording head31through the ink passage35. Accompanied by the ink which has flowed into the recording head31, the ink in the container1flows into the subtank unit33via the ink supply needle32.

FIG. 55is 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 wall1039, which locates upside of the liquid surface of ink K, is sloped to the liquid surface of ink K. The actuators106are mounted on the top wall1039such that the actuator106can contacts with ink through the through hole1cprovided on the top wall1039. The partition wall193cextends from the top wall1039downward to the ink surface. Furthermore, the present embodiment has a second partition wall193dwhich extends from the top wall10398inside the detection side ink chamber123band separates the detection side ink chamber123bat least into two detection side small ink chambers1123aand1123bsuch that ink housed in both of the detection side small ink chamber1123aand1123bcan communicate each other. Each of two actuators106aand106bis mounted on the top wall1039of each of the detection side small ink chambers1123aand1123b, respectively.

The volume of the ventilation side ink chamber123awhich is close to the ink supply port2is larger than the volume of the detection side ink chamber123bwhich is relatively far from the ink supply port2. Furthermore, the volume of the detection side small ink chamber1123awhich is close to the ink supply port2is larger than the volume of the detection side small ink chamber1123bwhich is relatively far from the ink supply port2within the detection side ink chamber123b. Therefore, ink in the ventilation side ink chamber123ais consumed at first. With consumption of ink advanced, the level of ink surface in the ventilation side ink chamber123adecreases. On the other hand, because the partition wall193ccand the top wall1039is coupled liquid-tightly or air-tightly, the detection side ink chamber123bis filled with ink until the level of ink surface reaches to the lower end193ccof the partition wall193c.

Next, if the ink surface in the ventilation side ink chamber123areaches to the lower end193ccof the partition wall193c, ink in the detection side small ink chamber1123ais beginning to be consumed because ink in the detection side small ink chamber1123aflows out to the ink supply port2. With consumption of ink advanced, the level of ink surface in the detection side small ink chamber1123adecreases. On the other hand, because the partition wall193ddand the top wall1039is coupled liquid-tightly or air-tightly, the detection side small ink chamber1123bis filled with ink until the level of ink surface reaches to the lower end193ddof the partition wall193d. Finally, if the level of ink surface of the detection side small ink chamber1123areaches to the lower end193ddof the partition wall193d, ink in the detection side small ink chamber1123bis beginning to be consumed because ink in the detection side small ink chamber1123bflows out to the ink supply port2.

Therefore, the actuators106aand106bcan 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 chamber123a, which is nearest to the ink supply port2, to the detection side small ink chamber1123aand further to the detection side small ink chamber1123b, which is farthest from the ink supply port2, the frequency of detecting an ink by the actuators106aand106bincreases 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 inFIG. 55has one second partition wall. As other embodiment, the container can have a plurality of partition walls so that the detection side ink chamber123bis separated into three or over detection side small ink chambers. A plurality of second partition walls separates the detection side ink chamber123binto two or over detection side small ink chambers. Each of the volumes of the of the detection side small ink chambers1123bcan 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 inFIG. 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 port2, to the detection side small ink chamber, which is relatively far from the ink supply port2. Then, the actuator106can 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 chamber1123a, which is near to the ink supply port2, to the detection side small ink chamber, which is far from the ink supply port2, the time interval of detecting a decrease of ink by the actuator106gradually 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 actuator106ais mounted nearby the partition wall193c, and the actuator106bis mounted nearby the partition wall193d. Therefore, even if the bubble G generates and enters into the detection side ink chamber123bwhen the ink inside the ventilation side ink chamber123adoes not reach to the lower end193ccof the partition wall193c, the bubble G stays in the upper side of boundary between the top wall1039and the partition wall193cor the upper side of boundary between the top wall1039and the side wall1030. Therefore, the bubble G does not attaches to the actuator106.

FIG. 56shows further other embodiment of the ink cartridge using the actuator106. The ink cartridge220A shown in FIG.56(A) has a first partition wall222provided such that it extends downward from the top face of the ink cartridge220A. Because there is a predetermined space between the lower end of the first partition wall222and the bottom face of the ink cartridge220A, ink can flows into the ink supply port230through the bottom face of the ink cartridge220A. A second partition wall224is formed such that the second partition wall224extends upward from the bottom face of the ink cartridge220A on the more ink supply port230side of the first partition wall222. Because there is a predetermined space between the upper end of the second partition wall224and the top face of the ink cartridge220A, ink can flows into the ink supply port230through the top face of the ink cartridge220A.

A ventilation side ink chamber225ais formed relatively near to the airhole233. On the other hand, a detection side ink chamber225bis formed relatively far from the airhole233. By the second partition wall224, the detection side ink chamber225band a detection side small ink chamber227are formed. The volume of the ventilation side ink chamber225ais larger than the volume of the detection side ink chamber225b. A detection side small ink chamber227is formed by providing a gap, which can generate the capillary phenomenon, between the first partition wall222and the second partition wall224. Therefore, the ink in the ventilation side ink chamber225ais collected to the detection side small ink chamber227by the capillary force of the detection side small ink chamber227. The first partition wall222can prevent that the gas or air bubble to enter into the detection side ink chamber225b. Furthermore, the ink level in the detection side ink chamber225bcan decrease steadily and gradually. Because the ventilation side ink chamber225ais formed at more inner part of the detection side ink chamber225b, seen from the ink supply port230, the ink in the detection side ink chamber225bis consumed after the ink in the ventilation side ink chamber225ais consumed.

Because ink is supplied from the ventilation side ink chamber225ato the detection side ink chamber225bby the detection side small ink chamber227, the actuator106does not influenced by the rolling of ink caused by the rolling of the ink cartridge220A, and actuator106can thus reliably measure the ink residual quantity. Furthermore, because the detection side small ink chamber227holds ink, the detection side small ink chamber227can prevent ink to flow backward from the detection side ink chamber225bto the ventilation side ink chamber225a.

The actuator106is mounted on the top wall1013of the ink supply port230side of the detection side ink chamber225b. The actuator106detects the ink consumption status inside the detection side ink chamber225b. The residual quantity of ink at the timing closed to the ink near end can be detected stably by mounting the actuator106on the side wall of the detection side ink chamber225b.

A airhole233is provided on the top wall1013of the ink cartridge220A. Moreover, a check valve228is provided on the airhole233. The leaking of ink outside the ink cartridge220A caused by the rolling of the ink cartridge220A can be prevented by the check valve228. Furthermore, the evaporation of ink from the airhole233of the ink cartridge220A can be prevented by providing the check valve228on the top face of the ink cartridge220A. If ink in the ink cartridge220A is consumed, and negative pressure inside the ink cartridge220A exceeds the pressure of the check valve228, the check valve228opens and introduces air into the ink cartridge220A. Then the check valve228closes to accelerate the drainage of ink from the ink cartridge220A.

FIG. 57shows further another embodiment of the ink cartridge using the actuator106. An ink cartridge180A shown inFIG. 57has a partition wall212awhich extends downward from the top face194cof the ink container194. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212a. Because lower end212aaof the partition wall212aand the bottom wall1aof the container194have a predetermined space, the ventilation side ink chamber213aand the detection side ink chamber213bcommunicates with each other. The actuator106is mounted on the top wall194cof the detection side ink chamber213b. The volume of the detection side ink chamber213bis smaller than the volume of the ventilation side ink chamber213a. The volume of the detection side ink chamber213bis preferably smaller than the half of the volume of the ventilation side ink chamber213a.

A buffer214a, that is a concave part for accepting the air bubble which enters to the ink cartridge180A is formed on the top wall194cof the detection side ink chamber213b. InFIG. 57, the buffer214ais formed as a concave part overhang upward from the top wall194cof the container194. The buffer214aaccepts the air bubble which enters into the detection side ink chamber213bmistakenly when the ink is filled in the detection side ink chamber213b. The buffer214athereby prevents the bubbles to attach to the actuator106. Therefore, the buffer214bprevents the malfunction of the actuator106to detect the ink end wrongly by the attaching of air bubble to the actuator106. Furthermore, by adjusting the volume of the detection side ink chamber213bby changing the length of the partition wall212aor changing the width between the partition wall212aand the side wall194b, the predetermined ink quantity remained after the detection of the ink end can be changed.

FIG. 58shows further another embodiment of the ink cartridge180. An ink cartridge180B shown inFIG. 58has a partition wall212bwhich is formed in L-shape. The partition wall212fextends from a top wall194c. A lower end212bbof the partition wall212bis longer than the lower end212aaof the partition wall212ain the embodiment shown in FIG.57. Therefore, gas existed in the ventilation side ink chamber213ais difficult to enter into the detection side ink chamber213b. Therefore, the malfunction of the actuator106to detects the ink end wrongly caused by the attaching of bubble to the actuator106can be further prevented. Furthermore, a gap is provided between the lower end212bband the bottom wall1a. A capillary force, which can hold ink, does not work on the gap provided between the lower end212bband the bottom wall1a.

FIG. 59shows further another embodiment of the ink cartridge180. An ink cartridge180C shown inFIG. 59has a partition wall212cwhich is sloped toward the ink surface. The partition wall212cextends from a top wall194c. The distance between the side wall194bof the ink cartridge180C and the partition wall212cnarrows toward downside. Therefore, gas existed in the ventilation side ink chamber213ais difficult to enter into the detection side ink chamber213b. Therefore, the malfunction caused by the attaching of bubble to the actuator106can be further prevented. Furthermore, a gap is provided between the lower end212ccand the bottom wall1aof the container194. A capillary force, which can hold ink, does not work on the gap provided between the lower end212ccof the partition wall212cand the side wall194b.

FIG. 60shows further another embodiment of the ink cartridge180. An ink cartridge180D shown inFIG. 60has a first partition wall212dwhich extends downward from the top face194cof the ink container194. Furthermore, a second wall extends from the first partition wall212dtoward the side wall194bsubstantially parallel to the ink surface. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the first partition wall212d. Furthermore, the second partition wall212eseparates the detection side ink chamber into a first detection side ink chamber213cand a second detection side ink chamber213d. A gap is provided between the bottom wall1aand the first partition wall212d. Furthermore, a gap is provided between the side wall194band the one end212eeof the second partition wall212e. A concave part is provided on a part of top wall194cto form a buffer214awhich accepts the bubble.

One end of the second partition wall212e, which extends from the partition wall212dtoward the side wall194b, extends until to the position where just under the buffer214b. Therefore, first, the first partition wall212dprevents the entering of bubble into the first detection side ink chamber213c. If the bubble enters into the detection side ink chamber213cmistakenly, the bubble is introduced to the position which is just under the buffer214aby the second partition wall212e. Therefore, the bubble is caught by the buffer214a. Therefore, the malfunction of the actuator106to detects the ink end wrongly by the attaching of bubble to the actuator106, which is provided in the second detection side ink chamber213d, can be further prevented.

FIG. 61shows further another embodiment of the ink cartridge180. An ink cartridge180E shown inFIG. 61has a partition wall212aas same as the partition wall212aof FIG.57. The partition wall212aextends downward from the top face194cof the ink container194. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212a. A gap is provided between the bottom wall1aand the partition wall212a. Furthermore, a concave part is provided on a part of top wall194cto form a buffer214bwhich accepts the bubble. A tapered face1040is provided between the buffer214band the actuator106.

Therefore, first, the partition wall212aprevents the entering of bubble into the detection side ink chamber213b. If the bubble enters into the detection side ink chamber213bmistakenly, the bubble is directly caught by the buffer214aor introduced to the buffer214balong the tapered face1040. Therefore, the malfunction of the actuator106to detects the ink end wrongly by the attaching of bubble to the actuator106can be further prevented. The shape and size of the buffer can be other arbitrary shape and size.

FIG. 62shows further another embodiment of the ink cartridge180. An ink cartridge180F shown inFIG. 62has a protruding part214f, which protrudes inside the container194, on a part of the top wall194c. The actuator106is mounted on the bottom part of the protruding part214f. A partition wall212fextends downward from the top face194c. A buffer214cis provided for each of the position between the actuator106and the partition wall212fand between the actuator106and the side wall194b. Therefore, the periphery of the actuator106is surrounded by the buffer214c.

FIG. 63shows further another embodiment of the ink cartridge180. An ink cartridge180G shown inFIG. 63has a partition wall212extends downward from the top face194c. The container194is separated in to a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212g. Uneven part is provided on the top wall194c, and two actuators106are mounted on the protruding part which protrudes inside the detection side ink chamber213b. The concave part of the top wall194cworks as a buffer214cwhich accepts bubble.

FIG. 64shows further other embodiment of the ink cartridge180. The ink cartridge1801shown inFIG. 64has a plurality of partition walls212h,212i,212j, and212k, each of which extends downward from the top face194cof the ink container194. The partition wall212his first partition wall, and the partition walls212i,212j, and212kare the second partition walls. Because each of lower ends212hh,212ii,212jj,and212kkof each of the partition walls212h,212i,212j, and212kand the bottom wall1aof the container194have a predetermined gap, the bottom part of the container194communicates with each other. The ink cartridge180I has a ventilation side ink chamber213aand a plurality of detection side small ink chambers213h,213i,213j, and213kseparated by the each of plurality of partition walls212h,212i,212jand212k. The bottom part of the ventilation side ink chamber213aand a plurality of the detection side small ink chambers213h,213i,213j, and213kcommunicates with each other. Each of the actuators106h,106i,106j, and106kis mounted on the top face194cof each of the plurality of the detection side small ink chambers213h,213i,213j, and213k, respectively. Each of the actuators106h,106i,106j, and106kis arranged on substantially center of the top face194cof each of the plurality of the detection side small ink chambers213h,213i,213j, and213k, respectively. The volume of the ink chamber is arranged such that the volume of the ventilation side ink chamber213awhich locates ink supply port187side is the largest. Moreover, the volume of the ink chamber gradually decreases as the distance from the ink supply port187increases. Therefore, the volume of the detection side small ink chamber213kwhich is farthest from the ink supply port187is the smallest among the volume of the ink chambers.

Because gas is introduced from the airhole233, ink is consumed from the ventilation side ink chamber213aof the ink supply port187side to the detection side ink chamber213k. For example, the ink in the ventilation side ink chamber213awhich is nearest to the ink supply port187is consumed, and during the ink level of the ventilation side ink chamber213adecreases, the other detection side small ink chambers are filled with ink. When the ink level in the ventilation side ink chamber213areaches to the lower end212hhof the partition wall212h, air enters into the detection side small ink chamber213h, and then the ink in the detection side small ink chamber213his beginning to be consumed. At this time, ink is filled in the detection side small ink chamber213i,213j, and213k. Furthermore, if the ink level in the detection side small ink chamber213hreaches to the lower end212iiof the partition wall212i, air enters into the detection side small ink chamber213i, and then the ink in the detection side small ink chamber213iis beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber213ato the detection side small ink chamber213k.

Each of the actuators106h,106i,106j, and106kis mounted on the top wall194cof each of the detection side small ink chambers. Therefore, the actuators106h,106i,106j, and106kcan detect the decrease of the ink quantity step by step. Furthermore, the volume of the ink chambers decreases from the ventilation side ink chamber213a, which is near to the ink supply port187, to the detection side small ink chamber213kgradually. 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. 65shows further other embodiment of the ink cartridge180.FIG. 65shows a cross section of an ink cartridge180J. The semiconductor memory device7and the actuator106are formed on the same circuit board610in the ink cartridge180J.

The semiconductor memory device7can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device7and the actuator106are formed on the same circuit board610, the mounting process can be finished at one time during mounting the semiconductor memory device7and the actuator106on the ink cartridge180C. Moreover, the working process during the manufacturing of the ink cartridge180C and the recycling of the ink cartridge180C can be simplified. Furthermore, the manufacturing cost of the ink cartridge180C can be reduced because the numbers of the parts can be reduced. Furthermore, a partition wall212J extends from the top wall194cdownward to the ink surface. The partition wall212J prevents the waving of ink or bubbling. The partition wall212J thereby prevents the malfunction of the actuator106.

The actuator106detects the ink consumption status inside the container194. The semiconductor memory device7stores the information of ink such as residual quantity of ink detected by the actuator106. That is, the semiconductor memory device7stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator106when detecting the ink consumption status. The semiconductor memory device7previously stores the resonant frequency of when ink inside the container194is full, that is, when ink is filled in the container194sufficiently, or when ink in the container194is end, that is, ink in the container194is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container194is 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 container194is full status or end status can be stored during the manufacturing of the container194. 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 container194is full status or end status in the semiconductor memory device7previously 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. 66shows further other embodiment of the ink cartridge180. The ink cartridge180K shown inFIG. 66has a plurality of partition walls212m,212n,212p, and212q, each of which extends downward from the top face194cof the ink container194. The partition wall212mis the first partition wall, and the partition walls212n,212p, and212qare the second partition walls. Because each of lower ends212mm,212nn,212pp,and212qqof the partition walls212m,212n,212p, and212q, respectively, and the bottom wall of the container194has a predetermined gap, the bottom part of the container194communicates with each other. Moreover, the length of the partition walls212m,212n,212p, and212qincreases from the side near to the airhole233in order. Therefore, each of the gap between the lower ends212mm,212nn,212pp,and212qqand the bottom wall1anarrows in the order of212m,212n,212p, and212q, sequentially.

Furthermore, the ink cartridge180K has a ventilation side ink chamber213aand a plurality of detection side small ink chamber213m,213n,213p, and213qseparated by the each of plurality of partition walls212m,212n,212pand212q. The bottom part of the ventilation side ink chamber213aand a plurality of the detection side small ink chambers213m,213n,213p, and213qcommunicates with each other. Each of the actuators106m,106n,106p, and106qis mounted on the top face194cof each of the plurality of the detection side small ink chambers213m,213n,213p, and213q, respectively. Each of the actuators106m,106n,106p, and106qis arranged on substantially center of the top face194cof each of the plurality of the detection side small ink chambers213m,213n,213p, and213q, respectively.

If ink is consumed, gas is introduced from the airhole233. Therefore, ink is consumed from the ventilation side ink chamber213awhich is near to the airhole233to the detection side ink chamber213q. For example, the ink in the ventilation side ink chamber213awhich is nearest to the airhole233is consumed, and during the ink level of the ventilation side ink chamber213adecreases, the other detection side small ink chambers are filled with ink. When the ink level in the ventilation side ink chamber213areaches to the lower end212mmof the partition wall212m, air enters into the detection side small ink chamber213m, and then the ink in the detection side small ink chamber213mis beginning to be consumed. At this time, ink is filled in the detection side small ink chamber213n,213p, and213q. Furthermore, if the ink level in the detection side small ink chamber213mreaches to the lower end212nnof the partition wall212n, air enters into the detection side small ink chamber213n, and then the ink in the detection side small ink chamber213nis beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber213ato the detection side small ink chamber213q.

Because the gap between the each of the lower ends and the bottom wall1anarrows gradually in the order from the lower ends212mm,212nn,212pp,and212qq,ink is consumed in the order from the ventilation side ink chamber213a, detection side small ink chamber212m,212n,212p, and212q, 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 chamber213mand213nmistakenly, and the actuator106detects the ink end mistakenly, the partition walls212pand212q, which is longer than the partition walls212mand212n, prevents the gas to enter into the detection side small ink chamber213pand213q. Therefore, the actuators106pand106qdo not mistakenly detect the ink end. Thus, in the present embodiment, the actuator106qdetects the ink end finally and most reliably.

Furthermore, because the partition walls212m,212n,212p, and212qprevent the waving of ink, the partition walls212m,212n,212p, and212qalso prevent the generation of the bubble.

Moreover, the intervals between each of the partition walls212m,212n,212p, and212qwith each other can be equal, and the interval between the partition wall212qand the side wall194bof the container1can be equal. In this case, the capacity of each of the detection side small ink chambers213m,213n,213p, and213qcan be adjusted by adjusting the length of the partition walls212m,212n,212p, and212q.

FIG. 67shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator106. In the present embodiment, the ink cartridge180A shown inFIG. 57is used. However, the ink cartridge in any of the ink cartridge shown inFIG. 58toFIG. 64also can be used. Furthermore, the ink cartridge of the other form also can be used. A plurality of ink cartridges180A is mounted on the inkjet recording apparatus which has a plurality of ink introducing members182and a holder184each corresponding to the each of ink cartridge180, respectively. Each of the plurality of ink cartridges180A contains different types of ink, for example, different color of ink. The actuator106, which detects at least acoustic impedance, is mounted on the each of top wall of the plurality of ink cartridge180A. The actuator106and a partition wall212aare provided for each top wall of the plurality of ink cartridge180A. The residual quantity of ink in the ink cartridge180can be detected by mounting the actuator106on the ink cartridge180. The partition wall212aprevents the waving and bubbling of ink.

FIG. 68shows a detail around the head member of the ink jet recording apparatus. In the present embodiment, the ink cartridge180A shown inFIG. 57is used. However, the ink cartridge in any of the ink cartridge shown inFIG. 58toFIG. 64also can be used. Furthermore, the ink cartridge of the other form also can be used. The ink jet recording apparatus has an ink introducing member182, a holder184, a head plate186, and a nozzle plate188. A plurality of nozzle190, which jet out ink, is formed on the nozzle plate188. The ink introducing member182has an air supply hole181and an ink introducing inlet183. The air supply hole181supplies air to the ink cartridge180. The ink introducing inlet183introduces ink from the ink cartridge180A. The ink cartridge180A has an air introducing inlet185and an ink supply port187. The air introducing inlet185introduces air from the air supply hole181of the ink introducing member182. The ink supply port187supplies ink to the ink introducing inlet183of the ink introducing member182. By introducing air from the ink introducing member182to the ink cartridge180, the ink cartridge180accelerates the supply of ink from the ink cartridge180A to the ink introducing member182. The holder184communicates ink, which is supplied from the ink cartridge180A through the ink introducing member182, to the head plate186. Ink is supplied to the head from the ink cartridge180A through the ink introducing member182and discharged to the recording medium from nozzle. In this way, the ink jet recording apparatus performs the printing on the recording medium.

FIG. 69is 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 inFIG. 69is 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 actuator106is used for an embodiment of the liquid censor that detects liquid. The ink cartridge of the embodiment shown inFIG. 69, comprises a container1which contains liquid K and includes top wall1030located upside of the liquid surface of ink K, an ink supply port2which supplies liquid K outside the container1, an actuator106which detects ink consumption status inside the container1, and a first partition wall193awhich partitions at least two ink chamber such that ink K in both of the ink chamber can communicate with each other inside the container1.

At least two ink chambers include a ventilation side ink chamber123awhich communicate with atmosphere and the detecting side ink chamber123b. The actuator106is mounted on the top wall1030of the ink chamber123b, and a porous member1000is provided in the detection side ink chamber123bas a buffer member. A coarse buffer material such as filter can be used instead of the porous member1000.

The airhole2cis provided on the top wall1030of the ventilation side ink chamber123awhich ventilates with atmosphere. The check valve228shown inFIG. 85can be used for airhole2c. However, the form of the airhole2cis not limited to the check valve228shown in FIG.85. If ink K is consumed and the container1inside decreases, air is introduced to the ventilation side ink chamber123afrom the outside of the container1by the airhole2c, and the airhole2cthus prevents the pressure inside the container1to be negative. Therefore, with the consumption of ink advanced, air is introduced to the ventilation side ink chamber123athrough the airhole2c, and the level of liquid surface of ink K decreases.

The partition wall193ais coupled with the top wall1030and side wall, not shown in the figure, liquid-tightly. Therefore, even the ink is consumed, ink K is sufficiently absorbed in the porous member1000and filled in the detection side ink chamber123bin the container1until the level of liquid surface of ink K reaches to the lower end193aaof the partition wall193a. When the ink consumption advances, and the level of liquid surface of ink K reaches to the lower end193aaof the partition wall193a, gas enters to the detection side ink chamber123b. The ink k absorbed by the porous member1000in the detection side ink chamber123bthereby flows out to the ink supply port2, and the medium existed around the actuator106changes from ink to atmosphere. Therefore, the actuator106can detect that the status inside the ink cartridge is in ink end status. Thus, it is the lower end193aato determine which level of the liquid surface of ink K to be a ink end. Furthermore, the volume of the detection side ink chamber132bis determined by the position of partition wall193ato the top wall1030. Therefore, the ink quantity remains inside the container1when detecting the ink end can be set by the position of the partition wall193ato the top wall1030and the height of the lower end193aain 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 wall193ain the container1, or if no buffer material is provide around the actuator106, 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 actuator106may detect mistakenly that there is enough ink in the container1if the ink attaches to the actuator106by the waving of ink even if there is little amount of ink in the container1. Moreover, there is also a danger that the actuator106may detect mistakenly that there is no ink if the bubble attaches to the actuator106even if the ink is filled in the container1.

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 wall193aprevents 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 actuator106and contact with the actuator106.

Moreover, the porous member1000is provided on the detection side ink chamber123bto intervene between the actuator106and the ventilation side ink chamber123a. Therefore, even if the bubbles generated in the ventilation side ink chamber123aenters into the detection side ink chamber123bmistakenly, the porous member1000prevents the bubbles to move close to the actuator106and contact with the actuator106.

Furthermore, because the porous member1000is provided in the detection side ink chamber123b, ink inside the detection side ink chamber123bdoes not wave by the vibration of the actuator106. Therefore, the actuator106can reliably and stably detect the ink consumption status in the container1.

The volume of the detection side ink chamber123bis preferably half or smaller than half of the volume of the ventilation side ink chamber123a. The detection side ink chamber123bpreferably has a width in a degree not to arise a capillary force such as to hold ink K.

The actuator106can 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 member1000is 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 toFIG. 19, which is formed in the actuator106, and introduce ink to ink supply port, referring to FIG.1.

The porous member1000of the embodiment shown inFIG. 69has a shape of rectangular parallelepiped. The porous member1000is filled in the detection side ink chamber123bsuch that the porous member1100fills from the periphery of the actuator106to the bottom wall1awhich is located below the ink surface in the ink cartridge.

A packing ring4and a valve body6are provided in the ink supply port2. Referring toFIG. 70, the packing ring4is engaged with the ink supply needle32communicating with a recording head31, in a fluid-tight manner. The valve body6is constantly and elastically contacted against the packing ring4by way of a spring5. When the ink supply needle32is inserted, the valve body6is pressed by the ink supply needle32so as to open an ink passage, so that ink inside the container1is supplied to the recording head31via the ink supply port2and the ink supply needle32. On an upper wall of the container1, there is mounted a semiconductor memory means7which stores data on ink inside the ink cartridge.

FIG. 71is 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 wall1030, which locates upside of the liquid surface of ink K. The actuators106are mounted on the top wall1030such that the actuator106can contacts with ink through the through hole1cprovided on the top wall1030. A first partition wall193cextends from the top wall1030downward to the ink surface. Furthermore, the present embodiment has a second partition wall193dwhich extends from the top wall1030inside the detection side ink chamber123band separates the detection side ink chamber123bat least into two detection side small ink chambers1123aand1123bsuch that ink housed in both of the detection side small ink chamber1123aand1123bcan communicate each other. The actuator106is mounted on the top wall1030of each of the detection side small ink chambers1123aand1123b, respectively.

Furthermore, a porous member1002and a porous member1003are provided to each of the inside of the detection side small ink chamber1123aand the detection side small ink chamber1123b.

Because gas is introduced from the airhole128, ink is consumed from the ventilation side ink chamber123a, which is near to the airhole128, to the detection side small ink chamber1123b, which is far from the airhole128. Therefore, during ink in the ventilation side ink chamber123awhich is nearest to the airhole128is consumed, the detection side ink chamber123bis filled with ink. When the ink level in the ventilation side ink chamber123areaches to the lower end193ccof the partition wall193c, air enters into the detection side small ink chamber1123a, and then the ink in the detection side small ink chamber1123ais beginning to be consumed. At this time, ink is filled in the detection side small ink chamber1123b. Furthermore, if the ink level in the detection side small ink chamber1123areaches to the lower end193ddof the second partition wall193d, air enters into the detection side small ink chamber1123b, and then the ink in the detection side small ink chamber1123bis beginning to be consumed. In this way, ink is sequentially consumed from the ventilation side ink chamber123ato the detection side small ink chamber1123b.

Because each of the actuators106is mounted on the top wall1030of each of the detection side small ink chambers1123aand1123b, the actuators106can detect the decrease of the ink quantity step by step. Furthermore, the volume of the detection side ink chamber123bis smaller than the volume of the ventilation side ink chamber213a. Furthermore, the volume of the detection side small ink chamber1123aand1123bgradually decreases from the detection side small ink chamber1123awhich is near to the airhole128to the detection side small ink chamber1123b, which is far from the airhole128. 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. 72shows further another embodiment of the ink cartridge using the actuator106. An ink cartridge180A shown inFIG. 72has a partition wall212awhich extends downward from the top face194cof the ink container194. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212a. Because lower end212aaof the partition wall212aand the bottom wall1aof the container194have a predetermined space, the ventilation side ink chamber213aand the detection side ink chamber213bcommunicates with each other.

A buffer member1005ais provided to block the communicating port between the ventilation side ink chamber213aand the detection side ink chamber213b. A filter-like material, which includes many holes on its surface, can be used for buffer member1050aif the buffer member closes the communicating port. Furthermore, the buffer member can be porous member. Therefore, the ventilation side ink chamber213aand the detection side ink chamber123bcommunicates each other through the buffer member1005a. Because the buffer member1005ais made from porous material, the buffer material pass through gas and liquid. However, if the buffer member1005aholds liquid by the capillary force, the buffer member becomes airtight. Therefore, the buffer member1050acan suppress bubbles to passing through the buffer member1050a. Thus, the buffer member1050acan prevents the bubbles, which is generated in the ventilation side ink chamber213a, to enter inside the detection side ink chamber213band attach to the actuator106.

The actuator106is mounted on the top wall194cof each of the ventilation side ink chamber213aand the detection side ink chamber213b. The volume of the detection side ink chamber213bis smaller than the volume of the ventilation side ink chamber213a. The volume of the detection side ink chamber213bis smaller than the half of the volume of the ventilation side ink chamber213ain the ink cartridge of according to the present embodiment.

A buffer214a, that is a concave part for accepting the air bubble which enters to the ink cartridge180A is formed on the top wall194cof the detection side ink chamber213b. InFIG. 72, the buffer214ais formed as a concave part overhang upward from the top wall194cof the container194. The buffer214aaccepts the air bubble which enters into the detection side ink chamber213bmistakenly when the ink is filled in the detection side ink chamber213b. The buffer214athereby prevents the bubbles to attach to the actuator106. Therefore, the buffer214bprevents the malfunction of the actuator106to detect the ink end wrongly by the attaching of air bubble to the actuator106. Furthermore, the level of ink surface on which the actuator106detects the ink end can be changed by changing the length of the partition wall212a. Furthermore, by changing the width between the partition wall212aand the side wall194b, the predetermined ink quantity remained after the detection of the ink end can be changed.

The ink cartridge180B shown inFIG. 73fills a porous member1005bin the detection side ink chamber123bof the ink cartridge180A shown in FIG.72. The porous member1005bis filled inside the detection side ink chamber213bfrom the top wall194cto the bottom wall194a. The porous member1005bcontacts with the actuator106. There is a case that the actuator106malfunctions by the entering of the air inside the detection side ink chamber213bwhen the ink cartridge fall down or when the detection side ink chamber213bmoves back and forth with the carriage. If the porous member1005bis provided on the detection side ink chamber213b, the porous member1005bcaptures air to prevent entering of air into the actuator106. Furthermore, because the porous member1005bholds ink, the porous member1005bcan prevent the actuator106to malfunction as detecting the ink end status as ink exist status which is caused by attaching of the ink on the actuator106when 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 chamber213bby changing the width between the side wall194band the partition wall212a. Furthermore, the level of ink surface on which the actuator106detects the ink end can be changed by adjusting the height of the lower end212aaof the partition wall212afrom the ink surface.

FIG. 74shows an ink cartridge180C, the porous member of which is constituted by two kinds of porous members1005cand1005dhaving a different hole diameter with each other. The porous member1005cis located closer to the actuator106than the porous member1005d. The hole diameter of the porous member1005cis larger than the hole diameter of the porous member1005d. The capillary force of the porous member1005d, which has small hole diameter, is larger than the capillary force of the porous member1005c, which has large hole diameter. Therefore, the ink, which once flows from the porous member1005cto the porous member1005d, does not flow backward to the porous member1005cbecause the capillary force works at the porous member1005d. Therefore, the porous members1005cand1005dprevents the attaching of ink to the actuator106by the waving of ink and thereby prevents the malfunction of the actuator106to detect the ink end status as ink exist status. The porous member1005ccan be formed by the material which has a lower affinity for liquid than the affinity for liquid of the material which forms the porous member1005d.

FIG. 75shows a cross section of an ink cartridge180D which is further other embodiment of the ink cartridge180using actuator106. Ribs1100, which protrudes inside the ink container194, are provided on the bottom side of the side wall194bof the detection side ink chamber213b. The porous member1005bwhich is provided inside the detection side ink chamber213bis gradually compressed by the ribs1100such that the area of the cross section on the horizontal plane of the porous member1005bgradually decreases downwards along the vertical direction. Therefore, the hole diameter of the porous member1005bdecreases gradually in the direction downward to the ink surface. Because the hole diameter of the lower part of the porous member1005breduced by the ribs1100, the ink, which once flows into the lower part of the porous member1005bdoes not flow backward to the upside of the porous member1005bby the capillary force. Furthermore, the porous member1005bof the present embodiment prevents ink to attach to the actuator106, which is mounted on the top wall194c, by the waving of ink. Therefore, the malfunction of the actuator106to 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 actuator106. FIG.76(A) is a cross sectional view along the longitudinal direction of a ink cartridge180E. FIG.76(B) shows B—B cross sectional view of the ink cartridge180E shown in FIG.76(A). A taper1110is provided on the lower side of the side wall of the detection side ink chamber213b. The width of the detection side ink chamber213bgradually narrows downward along the vertical direction by the taper1110. Therefore, the porous member1005bis compressed gradually by the taper1110such that the area of the cross section on the horizontal plane of the porous member1005bgradually decreases downwards along the vertical direction. Therefore, lower side of the hole diameter of the porous member1005bgradually becomes smaller than the upper side of the hole diameter of the porous member1005bby the taper1110. Because the hole diameter of the lower part of the porous member1005breduced by the taper1110, the ink, which once flows into the lower part of the porous member1005bdoes not flow backward to the upside of the porous member1005bby the capillary force. Furthermore, the porous member1005bof the present embodiment prevents ink to attach to the actuator106, which is mounted on the top wall194c, by the waving of ink. Therefore, the malfunction of the actuator106to detect the ink end status as the ink exist status can be prevented.

FIG. 77shows further another embodiment of the ink cartridge using actuator106. An ink cartridge180F shown inFIG. 77has a partition wall212cwhich is sloped toward the ink surface. A porous member1105eis filled in the detection side ink chamber213b. The partition wall212cextends from a top wall194c. The distance between the side wall194bof the ink cartridge180C and the partition wall212cgradually narrows toward downside. Therefore, the porous member1005eis compressed gradually by the partition wall212csuch that the area of the cross section on the horizontal plane of the porous member1005bgradually decreases toward downside. Therefore, lower side of the hole diameter of the porous member1005egradually becomes smaller than the upper side of the hole diameter of the porous member1005eby the partition wall212c. Because the hole diameter of the lower part of the porous member1005eis reduced by the partition wall212c, the ink, which once flows into the lower part of the porous member1005edoes not flow backward to the upside of the porous member1005eby the capillary force. Furthermore, the porous member1005eof the present embodiment prevents ink to attach to the actuator106, which is mounted on the top wall194c, by the waving of ink. Therefore, the malfunction of the actuator106to detect the ink end status as the ink exist status can be prevented.

Moreover, gas existed in the ventilation side ink chamber213ais difficult to enter into the detection side ink chamber213b. Therefore, the malfunction caused by the attaching of bubble to the actuator106can be further prevented. Furthermore, a gap is provided between the lower end212ccand the bottom wall2aof the ink cartridge180F. A capillary force, which can hold ink, does not work on the gap provided between the lower end212ccand the side wall194b.

FIG. 78shows further another embodiment of the ink cartridge using the actuator106. An ink cartridge180G shown inFIG. 78has a partition wall212bwhich is formed in L-shape. The partition wall212bextends from a top wall194c. A lower end212bbof the partition wall212bis longer than the lower end212aaof the partition wall212ain the embodiment shown inFIG. 72toFIG. 77. Aporous member1005fis filled in the detection side ink chamber213b.

A porous member1005g, which is a bottom part of porous member1005f, is sandwiched and compressed by the lower end212bband the side wall194b. Therefore, the hole diameter of the porous member1005gis smaller than the hole diameter of the porous member1005f. Thus, the hole diameter of the porous member decreases from the porous member1005f, which locates nearby the actuator106, to the porous member1005gand further to porous member1005h. The hole diameter of the porous member1005fthereby decreases step by step downward to the ink surface. Therefore, the ink, which once flows into the lower part of the porous member1005fdoes not flow backward to the upside of the porous member1005fby the capillary force. Furthermore, the porous member1005fof the present embodiment prevents ink to attach to the actuator106, which is mounted on the top wall194c, by the waving of ink. Therefore, the malfunction of the actuator106to detect the ink end status as the ink exist status can be prevented.

Moreover, the bottom end212bbis longer than the lower end212aaof the partition wall212aof the embodiments shown inFIG. 72to FIG.77. Therefore, gas existed in the ventilation side ink chamber213ais difficult to enter into the detection side ink chamber213b. Therefore, the malfunction of the actuator106to detects the ink end wrongly caused by the attaching of bubble to the actuator106can be further prevented. Furthermore, a gap is provided between the lower end212bband the bottom wall2a. A capillary force, which can hold ink, does not work on the gap provided between the lower end212bband the bottom wall2a.

FIG. 79shows further another embodiment of the ink cartridge180. An ink cartridge180H shown inFIG. 79has a first partition wall212dwhich extends downward from the top face194cof the ink container194. Furthermore, a second wall extends from the first partition wall212dtoward the side wall194bsubstantially parallel to the ink surface. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the first partition wall212d. Furthermore, the second partition wall212eseparates the detection side ink chamber into a first detection side ink chamber213cand a second detection side ink chamber213d. A gap is provided between the bottom wall2aand the lower end212ddof the first partition wall212d. Furthermore, a gap is provided between the side wall194band the one end212eeof the second partition wall212e. A concave part is provided on a part of top wall194cto form a buffer214awhich accepts the bubble. Furthermore, porous member1005iis filled inside the first detection side small ink chamber213c. One end212eeof the second partition wall212e, which extends toward the side wall194b, extends until to the position where just under the buffer214b.

Therefore, first, the first partition wall212dprevents the entering of bubble into the first detection side ink chamber213c. If the bubble enters into the detection side ink chamber213cmistakenly, the bubble is absorbed by the porous member1005i. Furthermore, if the bubble reaches to the second partition wall212e, the bubble is introduced to the position which is just under the buffer214aby the second partition wall212e. Therefore, the bubble is caught by the buffer214a. Therefore, the malfunction of the actuator106to detects the ink end wrongly by the attaching of bubble to the actuator106, which is provided in the second detection side ink chamber213d, can be further prevented.

FIG. 80shows further another embodiment of the ink cartridge180. An ink cartridge180I shown inFIG. 80has a partition wall212aas same as the partition wall212aof FIG.72. The partition wall212aextends downward from the top face194cof the ink container194. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212a. A gap is provided between the bottom wall1aand the partition wall212a. A porous member1005bis provided inside the detection side ink chamber213b. Furthermore, a concave part is provided on a part of top wall194cto form a buffer214bwhich accepts the bubble. A tapered face1040is provided between the buffer214band the actuator106.

Therefore, first, the partition wall212aprevents the entering of bubble into the detection side ink chamber213b. If the bubble enters into the detection side ink chamber213bmistakenly, the bubble is absorbed by the porous member1005b. If the bubble reaches to the upper side of the detection side ink chamber213b, the bubble is directly caught by the buffer214aor introduced to the buffer214balong the tapered face1040. Therefore, the malfunction of the actuator106to detects the ink end wrongly by the attaching of bubble to the actuator106can be further prevented. The shape and size of the buffer can be other arbitrary shape and size.

Moreover, the second partition wall212ein the embodiment shown inFIG. 79can be provided on the ink cartridge180I of the embodiment shown inFIG. 80such that the second partition wall212eextends from the first partition wall212atoward the side wall214bin the direction parallel to the ink surface. In this case, one end212eeof the second partition wall212eis extended to the position just under the taper face1040.

FIG. 82shows further another embodiment of the ink cartridge180using actuator106. An ink cartridge180K shown inFIG. 82has a protruding part214f, which protrudes inside the container194, on a part of the top wall194c. The actuator106is mounted on the bottom part of the protruding part214f. A partition wall212fextends downward from the top face194c. A buffer214cis provided for each of the position between the actuator106and the partition wall212aand between the actuator106and the side wall194b. Therefore, the periphery of the actuator106is surrounded by the buffer214c. A porous member1005bis provided inside the detection side ink chamber213b. By providing the actuator106on the protruding part214f, positioning for mounting the actuator106on the ink cartridge180J becomes easier when manufacturing the ink cartridge180J.

FIG. 82shows further another embodiment of the ink cartridge180using actuator106. An ink cartridge180K shown inFIG. 82has a partition wall212aextends downward from the top face194c. The container194is separated into a ventilation side ink chamber213aand a detection side ink chamber213bby the partition wall212g. Uneven part is provided on the top wall194c, and two actuators106are mounted on the protruding part which protrudes inside the detection side ink chamber213b. The concave part of the top wall194cworks as a buffer214cwhich accepts bubble. Furthermore, a porous member1005bis provided inside the detection side ink chamber213b. By providing two actuators106on the protruding part214f, detecting the ink consumption status mistakenly can be prevented. The number of the actuators106can be more than three. Moreover, as shown inFIG. 81, positioning for mounting the actuator106on the ink cartridge180K becomes easier when manufacturing the ink cartridge180K. The number of uneven part and the number of the actuator106can be further increased.

FIG. 83shows further other embodiment of the ink cartridge180using actuator106. The ink cartridge180M shown inFIG. 83has a plurality of partition walls212f,212g,212h, and212i, each of which extends downward from the top face194cof the ink container194. The partition wall212fis first partition wall, and the partition walls212g,212h, and212iare the second partition walls. Because each of lower ends212ff,212gg,212hh,and212iiof each of the partition walls212f,212g,212h, and212iand the bottom wall2aof the container194have a predetermined gap, the bottom part of the container194communicates with each other. The ink cartridge180M has a ventilation side ink chamber213aand a plurality of detection side small ink chambers213f,213g,213h, and213iseparated by the each of plurality of partition walls212f,212g,212hand212i. The bottom part of a plurality of the detection side small ink chambers213f,213g,213h, and213icommunicate with each other. Each of the actuators106f,106g,106h, and106iis mounted on the top face194cof each of the plurality of the detection side small ink chambers213f,213g,213h, and213i, respectively. Each of the actuators106f,106g,106h, and106iis arranged on substantially center of the top face194cof each of the plurality of the detection side small ink chambers213f,213g,213h, and213i, respectively.

The volume of the ventilation side ink chamber213a, and the detection side small ink chamber213f,213g,213h, and213iare gradually decreases as the distance from the airhole128increases to the inner side of the ink container194. Therefore, the volume of the ink chambers gradually decreases in the order from the ventilation side ink chamber213a, the detection side small ink chamber213f,213g,213h, and213i. Therefore, the interval of the mounting position of the actuator106is wider on the airhole128side and becomes narrower as the distance from the airhole increases to the inner side of the ink container194.

Furthermore, each of the porous members1005f,1005g,1005hand1005iare filled in the each of the detection side small ink chambers213f,213g,213h, and213i. The each of the porous members1005f,1005g,1005hand1005iare filled from the detection side small ink chambers213f, which is near to the airhole128, to the detection side small ink chamber213i, which is far from the airhole128, sequentially. The porous members are designed such that the hole diameter increases in the order from the porous member1005f,1005g,1005hand1005i. The porous members can be formed such that the affinity for ink decreases in the order from the porous member1005f,1005g,1005hand1005i.

Because gas is introduced from the airhole128, ink is consumed from the ventilation side ink chamber213aof the airhole128side to the detection side ink chamber213i. For example, the ink in the ventilation side ink chamber213awhich is nearest to the airhole128is consumed, and during the ink level of the ventilation side ink chamber213adecreases, the other detection side small ink chambers213f,213g,213h, and213iare filled with ink. When the ink level in the ventilation side ink chamber213areaches to the lower end212ffof the partition wall212f, air enters into the detection side small ink chamber213f, and then the ink in the detection side small ink chamber213fis beginning to be consumed. The ink level in the detection side small ink chamber213f thereby begin to decrease. At this time, ink is filled in the detection side small ink chambers213g,213h, and213i. In this way, ink is sequentially consumed from the ventilation side ink chamber213ato the detection side small ink chamber213i.

Furthermore, the porous members are designed such that the hole diameter increases in the order from the porous members1005f,1005g,1005hand1005i. Therefore, ink is consumed in the order from the detection side small ink chamber213fwhich is relatively near to the airhole128to the detection side small ink chamber213I which is far from the airhole128, sequentially. Moreover, the porous members1005f,1005g,1005hand1005I prevent ink to flow back from the detection side small ink chamber213fto the detection side small ink chamber213i.

In the present embodiment, each of the actuators106f,106g,106h, and106iis mounted on the top wall194cof each of the detection side small ink chambers213f,213g,213h, and213I with interval. Therefore, the actuators106f,106g,106h, and106ican detect the decrease of the ink quantity step by step. Furthermore, the volume of the ink chambers decreases from the ventilation side ink chamber213ato the detection side small ink chamber213igradually. 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. 84shows further other embodiment of the ink cartridge180using actuator106. In the ink cartridge180N shown inFIG. 84, porous members1006f,1006g,1006hand1006iare provided in the ink cartridge180N such that each porous members1006f,1006g,1006hand1006icloses the each of the communication port of the ventilation side ink chamber213a, the detection side small ink chambers213f,213g,213h, and213i. Each of the ventilation side ink chamber213a, the detection side small ink chambers213f,213g,213h, and213icommunicates each other through the porous members1006f,1006g,1006hand1006i. Therefore, the porous members prevent the bubble, which is generated in the ink container194, to enter into the ventilation side ink chamber213a, the detection side small ink chambers213f,213g,213h, and213i. Therefore, even if the bubble generates in one of the detection side ink chambers, and one of the actuators106f,106g,106h, and106idetects the ink end status mistakenly, the other actuators106f,106g,106h, and106ido not detect the ink end status mistakenly.

FIG. 85shows further other embodiment of the ink cartridge using the actuator106. The ink cartridge220A shown inFIG. 85has a first partition wall222provided such that it extends downward from the top wall of the ink cartridge220A. Because there is a predetermined space between the lower end of the first partition wall222and the bottom wall3aof the ink cartridge220A, ink can flows into the ink supply port230through the bottom wall3aof the ink cartridge220A. A second partition wall224is formed such that the second partition wall224extends upward from the bottom wall3aof the ink cartridge220A on the more ink supply port230side of the first partition wall222. Because there is a predetermined space between the upper end of the second partition wall224and the top wall221of the ink cartridge220A, ink can flows into the ink supply port230through the top wall221of the ink cartridge220A.

A ventilation side ink chamber225ais formed relatively near to the airhole233. On the other hand, a detection side ink chamber225bis formed relatively far from the airhole233. By the second partition wall224, the detection side ink chamber225band a detection side small ink chamber227are formed. The detection side small ink chamber227is formed between the first partition wall222and the second partition wall224. The detection side small ink chamber227is formed by providing a gap, which can generate the capillary phenomenon, between the first partition wall222and the second partition wall224. Therefore, the ink in the ventilation side ink chamber225ais collected to the detection side small ink chamber227by the capillary force of the detection side small ink chamber227. Therefore, the detection side small ink chamber227can prevent that the air bubble to enter into the detection side ink chamber225b. Furthermore, the ink level in the detection side ink chamber225bcan decrease steadily and gradually.

Moreover, a porous member1005gis provided inside the detection side ink chamber225b. The volume of the ventilation side ink chamber225ais larger than the volume of the detection side ink chamber225b. Because the ventilation side ink chamber225ais formed closer to the airhole223than the detection side small ink chamber225b, the ink in the detection side small ink chamber225bis consumed after the ink in the ventilation side ink chamber225ais consumed. Furthermore, the waving of ink inside the detection side small ink chamber225bis prevented by providing the porous member1005ginside the detection side small ink chamber225b. Moreover, the porous member1005gprevents the bubble, which is entered from the ink supply port230, to attach to the actuator106.

Furthermore, the capillary force of the porous member1005gis greater than the capillary force of the detection side small ink chamber227. The porous member1005gthereby prevents ink to flow back from the ink supply port230to the ventilation side small ink chamber225a. The capillary force of the porous member1005gcan be increased by adjusting the hole diameter. Moreover, the capillary force of the porous member1005gcan be increased by compressing the porous member1005g.

A airhole233is provided on the top wall of the ink cartridge220A. Moreover, a check valve228is provided on the airhole233for preventing the leaking of ink from the airhole233. The leaking of ink outside the ink cartridge220A caused by the rolling of the ink cartridge220A can be prevented by the check valve228. Furthermore, the evaporation of ink from the airhole233of the ink cartridge220A can be prevented by providing the check valve228on the top face of the ink cartridge220A. If ink in the ink cartridge220A is consumed, and negative pressure inside the ink cartridge220A exceeds the pressure of the check valve228, the check valve228opens and introduces air into the ink cartridge220A. Then the check valve228closes to accelerate the drainage of ink from the ink cartridge220A.

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 actuator106can detect the liquid status inside the liquid container by any method mentioned above.

FIG. 86shows further other embodiment of the ink cartridge180.FIG. 86shows a cross section of an ink cartridge180P. The semiconductor memory device7and the actuator106are formed on the same circuit board610in the ink cartridge180P.

A different-type O-ring614is mounted on the side wall194bsuch that the different-type O-ring614surrounds the actuator106. A plurality of caulking part616is formed on the side wall194bto couple the circuit board610with the container194. By coupling the circuit board610with the container194using the caulking part616and pushing the different-type O-ring614to the circuit board610, the vibrating region of the actuator106can contacts with ink, and at the same time, the inside of the ink cartridge is sealed from outside of the ink cartridge.

A terminals612are formed on the semiconductor memory device7and around the semiconductor memory device7. The terminal612transfer the signal between the semiconductor memory device7and outside the ink jet recording apparatus. The semiconductor memory device7can be constituted by the semiconductor memory which can be rewritten such as EEPROM. Because the semiconductor memory device7and the actuator106are formed on the same circuit board610, the mounting process can be finished at one time during mounting the semiconductor memory device7and the actuator106on the ink cartridge180P. Moreover, the working process during the manufacturing of the ink cartridge180C and the recycling of the ink cartridge180P can be simplified. Furthermore, the manufacturing cost of the ink cartridge180P can be reduced because the numbers of the parts can be reduced.

The actuator106detects the ink consumption status inside the container194. The semiconductor memory device7stores the information of ink such as residual quantity of ink detected by the actuator106. That is, the semiconductor memory device7stores the information related to the characteristic parameter such as the characteristic of ink and the ink cartridge used for the actuator106when detecting the ink consumption status. The semiconductor memory device7previously stores the resonant frequency of when ink inside the container194is full, that is, when ink is filled in the container194sufficiently, or when ink in the container194is end, that is, ink in the container194is consumed, as one of the characteristic parameter. The resonant frequency when the ink inside the container194is 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 container194is full status or end status can be stored during the manufacturing of the container194. 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 container194is full status or end status in the semiconductor memory device7previously 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. 87shows further other embodiment of the ink cartridge180. The ink cartridge180Q shown inFIG. 87has a plurality of partition walls212p,212q, and212r. The partition walls212p,212q, and212rseparates the ink container194into the ventilation side ink chamber213aand the detection side small ink chamber213p,213q, and213r. The partition wall212pis the first partition wall, and the partition walls212qand212rare the second partition walls. Each of porous members1005p,1005q, and1005rare provided in the each of the detection side small ink chamber213p,213q, and213r. Furthermore, each of partition walls212p,212q, and212rare provided on the top wall194cwith substantially equal intervals. Furthermore, each of the partition walls212p,212q, and212rextends from the top wall194ctoward the bottom wall2a. Each of the partition walls212p,212q, and212rhave different length. Moreover, the length of the partition walls212p,212q, and212rincreases in the order of the partition wall212p,212q, and212r. Therefore, even the interval between the each of the partition walls212p,212q, and212ris 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 walls212p,212q, and212rincreases with the increase of the distance from the airhole128, gas is most difficult to enter into the detection side small ink chamber213rwhich is farthest from the airhole128. Therefore, the actuator106rcan detect the ink existence most accurately among the actuators106p,106q, and106rwhich is mounted on the each of the detection side small ink chamber213p,213q, and213r.

FIG. 88shows an embodiment around a recording head of part of the ink cartridge and an ink jet recording apparatus which uses the actuator106. In the present embodiment, the ink cartridge180A shown inFIG. 72is used. However, the ink cartridge in any of the ink cartridge shown inFIG. 73toFIG. 84also can be used. Furthermore, the ink cartridge of the other form also can be used. A plurality of ink cartridges180A is mounted on the inkjet recording apparatus which has a plurality of ink introducing members182and a holder184each corresponding to the each of ink cartridge180, respectively. Each of the plurality of ink cartridges180A contains different types of ink, for example, different color of ink. The actuator106, which detects at least acoustic impedance, is mounted on the each of top wall of the plurality of ink cartridge180A. The actuator106, a partition wall212a, and a porous member1005bare provided for each top wall of the plurality of ink cartridge180A. The residual quantity of ink in the ink cartridge180can be detected by mounting the actuator106on the ink cartridge180. The partition wall212aprevents the waving and bubbling of ink.

FIG. 89shows a detail around the head member of the ink jet recording apparatus. In the present embodiment, the ink cartridge180A shown inFIG. 72is used. However, the ink cartridge in any of the ink cartridge shown inFIG. 73toFIG. 84also can be used. Furthermore, the ink cartridge of the other form also can be used. The ink jet recording apparatus has an ink introducing member182, a holder184, a head plate186, and a nozzle plate188. A plurality of nozzle190, which jet out ink, is formed on the nozzle plate188. The ink introducing member182has an air supply hole181and an ink introducing inlet183. The air supply hole181supplies air to the ink cartridge180. The ink introducing inlet183introduces ink from the ink cartridge180A. The ink cartridge180A has an air introducing inlet185and an ink supply port187. The air introducing inlet185introduces air from the air supply hole181of the ink introducing member182. The ink supply port187supplies ink to the ink introducing inlet183of the ink introducing member182. By introducing air from the ink introducing member182to the ink cartridge180, the ink cartridge180accelerates the supply of ink from the ink cartridge180A to the ink introducing member182. The holder184communicates ink, which is supplied from the ink cartridge180A through the ink introducing member182, to the head plate186. Ink is supplied to the head from the ink cartridge180A through the ink introducing member182and discharged to the recording medium from nozzle. In this way, the ink jet recording apparatus performs the printing on the recording medium.

FIG. 90is 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 inFIG. 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 device3is utilized. An ink supply port2which comes in contact with an ink supply needle of the recording apparatus in a sealed manner is provided in a container1which houses the ink. In an outside portion of a bottom face1aof the container1, the elastic wave generating device3is 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 device3is provided in a slightly upward position from the ink supply port2. Moreover, an elastic wave receiving means may be separately provided instead, so that the elastic wave generating device3is used as an elastic wave generating device only.

A packing ring4and a valve body6are provided in the ink supply port2. Referring toFIG. 91, the packing ring4is engaged with the ink supply needle32communicating with a recording head31, in a fluid-tight manner. The valve body6is constantly and elastically contacted against the packing ring4by way of a spring5. When the ink supply needle32is inserted, the valve body6is pressed by the ink supply needle32so as to open an ink passage, so that ink inside the container1is supplied to the recording head31via the ink supply port2and the ink supply needle32. On an upper wall of the container1, there is mounted a semiconductor memory means7which stores data on ink inside the ink cartridge.

Furthermore, a porous member1050is provided inside the container1. A gap is provided between the porous member1050and the elastic wave generating device3to form an ink layer. By providing the porous member1050inside the container1, the porous member1050prevents the waving or bubbling of ink inside the container1when 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 device3, the elastic wave generating device3can accurately detect the ink consumption status.

Furthermore, the hole diameter of porous member1050is set such that the porous member1050does not absorbs ink existed in the ink layer1060when the ink surface reaches to the ink layer1060by the consumption of ink inside the container1. In other words, the porous member1050is designed such that the capillary force works in the porous member1050does not hold ink in the container1. Therefore, ink does not remain in the porous member1050by its own weight and remains in the ink layer1060when the ink inside the container1is in an ink near end status.

An airhole, not shown in the figure, is provided on the container1. The airhole is provided on the upper side of the ink surface to communicate with outside of container1. Air is introduced inside the container1by the airhole, and ink flows downward by its own weight with advance of ink consumption. The residual ink thereby stays in the ink layer1060. Because the porous member1050is provided inside the container1, the elastic wave generating device3can 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 member1050in the container1. Therefore, the elastic wave generating device3can detect the ink surface accurately when the ink surface inside the container1reaches to the lower end of the porous member1050, and ink surface exists within the ink layer1060.

Moreover, the width of the gap between the porous member1050and the elastic wave generating device3is not limited. To suppress the bubbling of ink as much as possible, the width of ink layer1060is reduced by providing the porous member1050on lower side of the container1. If the width of the ink layer1060is small, the elastic wave generating device3can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container1. Therefore, the elastic wave generating device3can accurately detect the ink quantity and existence of ink when the ink consumption status is near to the ink end status. Therefore, the porous member1050is preferably located nearby the elastic wave generating device3without limiting the width of gap between the porous member1050and elastic wave generating device3. Moreover, even the bubble of ink generates, because the bubble of ink is absorbed in the porous member1050, the bubble does not stays around the elastic wave generating device3. The porous member1050thereby prevents the elastic wave generating device3to detect the ink consumption status mistakenly.

FIG. 91is a cross sectional view showing an embodiment of a major part of the ink-jet recording apparatus suitable for the ink cartridge shown inFIG. 90. Acarriage30capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit33, while the recording head31is provided in a lower face of the subtank unit33. Moreover, the ink supply needle32is provided in an ink cartridge mounting face side of the subtank unit33.

While the recording apparatus is operating, a drive signal is supplied to the elastic wave generating device3at 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 device3is transferred to the ink by propagating through the bottom face1aof the container1so as to be propagated to the ink.

By adhering the elastic wave generating device3to the container1, since a process of embedding electrodes for use in detecting the liquid surface is unnecessary in the course of forming the container1, 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 member1050is provided inside the container1. By providing the porous member1050inside the container1, the porous member1050prevents the waving or bubbling of ink inside the container1when 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 device3, the elastic wave generating device3can accurately detect the ink consumption status.

FIG. 92is a detailed cross sectional view of a subtank unit33. The subtank unit33comprises the ink supply needle32, the ink chamber34, a flexible valve36and a filter37. In the ink chamber34, the ink is housed which is supplied from the ink cartridge via ink supply needle32. The flexible valve36is so designed that the flexible valve36is opened and closed by means of the pressure difference between the ink chamber34and the ink supply passage35. The subtank unit33is so constructed that the ink supply passage35is communicated with the recording head31so that the ink can be supplied up to the recording head31.

Referring toFIG. 91, when the ink supply port2of the container1is inserted through the ink supply needle32of the subtank unit33, the valve body6recedes against the spring5, so that an ink passage is formed and the ink inside the container1flows into the ink chamber34. At a stage where the ink chamber34is filled with ink, a negative pressure is applied to a nozzle opening of the recording head31so as to fill the recording head with ink. Thereafter, the recording operation is performed.

When the ink is consumed in the recording head31by the recording operation, a pressure in the downstream of the flexible valve36decreases. Then, the flexible valve36is positioned away from a valve body38so as to become opened. When the flexible valve36is opened, the ink in the ink chamber34flows into the recording head31through the ink passage35. Accompanied by the ink which has flowed into the recording head31, the ink in the container1flows into the subtank unit33via the ink supply needle32.

According to the embodiment shown in FIG.91andFIG. 92, the elastic wave generating device3and the porous member1050are provided also in the subtank unit33. The porous member1050is provided nearby the elastic wave generating device3. A gap is provided to form a ink layer1060between the elastic wave generating device3and the porous member1050.

The elastic wave generating device3detects the ink quantity or existence of ink inside the subtank unit33. In case of the present embodiment, because the porous member1050is provided inside the subtank unit33, if the width of the ink layer1060becomes small, the elastic wave generating device3can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container1because the porous member1050is provided inside the subtank unit33. Therefore, the elastic wave generating device3can accurately detect the ink surface when the ink surface inside the sub tank unit33reaches to the lower end of the porous member1050and exits between the ink layer1060. Moreover, the elastic wave generating device3can detect the ink quantity and existence of ink inside the subtank unit33accurately.

Moreover, because the elastic wave generating device3is provided inside the subtank unit33, the elastic wave generating device3can detect the ink quantity and the existence of ink inside the subtank unit33even when the ink inside the ink cartridge180is used up. Therefore, the ink jet recording apparatus can judge whether the printing process can be continued or not.

The elastic wave generating device3and the porous member1050are provided inside the container1of the ink cartridge in the embodiment shown in FIG.91. Moreover, as shown in FIG.91andFIG. 92, the elastic wave generating device3and the porous member1050are also provided inside the subtank unit33. Therefore, the elastic wave generating device3and the porous member1050are provided on both of the ink cartridge shown in FIG.91and the subtank unit33shown in FIG.92. However, the elastic wave generating device3and the porous member1050can be provided to only one of the ink cartridge shown inFIG. 91or the subtank unit33shown in FIG.92.

According to the embodiment shown inFIG. 93, if the ink absorbing member74and75expose from the ink by consumption of ink inside the container1, ink contained in the ink absorbing member74and75, which is made from a porous material, flows out by the own weight and is supplied to the recording head31. If ink is used up, the ink absorbing member74and75absorbs the ink remained in the through hole1c, the ink is thereby drained from the concave part of the through hole1c. Therefore, the condition of the reflective wave of the elastic wave generated by the elastic wave generating device70at the ink end status changes, and thus the timing of ink end status can be further accurately detected. Furthermore, the ink absorbing member74and75are designed such that the capillary force works in the ink absorbing member74and75is equal to the capillary force which can hold ink or greater than the capillary force which can hold ink. The ink absorbing member74and75thereby absorb ink remained in the through hole1c.

FIGS.94(I)-94(V) show manufacturing methods of the elastic wave generating device3,15,16and17. A base plate20is formed by material such as the burning-endurable ceramic. Referring to FIG.94(I), first of all, a conductive material layer21which becomes an electrode at one side is formed on the base plate20. Next, referring to FIG.94(II), a green sheet22serving as piezoelectric material is placed on the conductive material layer21. Next, referring to FIG.94(III), the green sheet22is 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 sheet22at a burning temperature of, for example, 1200° C. Next, referring to FIG.94(IV), a conductive material layer23serving as other electrode is formed on the surface of the green sheet22so as to be polarized in a capable of flexural-oscillation manner. Finally, referring to FIG.94(V), the base plate20is cut along each element. By fixing the base plate20in a predetermined face of the container1by use of adhesive or the like, the elastic wave generating device3can 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. 95shows another embodiment of the elastic wave generating device3shown in FIG.94. In the embodiment shown inFIG. 94, the conductive material layer21is used as a connecting electrode. On the other hand, in the embodiment shown inFIG. 95, connecting terminals21aand23aare formed by a solder in an upper position than the surface of the piezoelectric material layer comprised of the green sheet22. By the provision of the connecting terminals21aand23a, the elastic wave generating device3can 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 inFIGS. 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 so on. Utilizing these, the state of the liquid inside the liquid container can be detected. The elastic wave generating device3may 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 device3, 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 device3varies 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 device3generates the elastic wave and then the wave reflected from the ink surface arrives at the elastic wave generating device3. 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 device3in the container1, when the ink of the ink cartridge approaches (decreases to) an ink-end state and the elastic wave generating device3can no longer receive the reflected wave, it is judged as an ink-near-end and thus can give indication to replace the cartridge.

FIG. 96shows an ink cartridge according to another embodiment of the present invention. Plural elastic wave generating device41-44are provided on the side wall of the container1, spaced at a variable interval from one another in the vertical direction. In the ink cartridge shown inFIG. 96, whether or not the ink is present at mounting levels of respective elastic wave generating device41-44can be detected by whether or not the ink is present at respective positions of the elastic wave generating device41-44. For example, suppose that the liquid level of ink is at a point between the elastic wave generating device44and43. Then, the elastic wave generating device44detects and judges that the ink is empty while the elastic wave generating device41,42and43detect 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 device44and43. Thus, provision of the plural elastic wave generating device41-44makes possible to detect the ink remaining amount in a step-by-step manner.

FIG.97andFIG. 98show ink cartridges according to still another embodiments of the present invention. In an embodiment shown inFIG. 97, an elastic wave generating device65is mounted in a bottom face1aformed aslope in the vertical direction. In an embodiment shown inFIG. 98, an elastic wave generating device66of an elongated shape in the vertical direction is provided in the vicinity of the bottom face of a side wall1b.

According to the embodiments shown in FIG.97andFIG. 98, when part of the elastic wave generating device65and66is 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 device65continuously 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 member1050is provided inside the container1. The porous member1050prevents the waving and bubbling of ink inside the container1. The porous member1050thereby prevents the elastic wave generating device65and66to detects the ink existence mistakenly.

In the embodiment shown inFIG. 97, the porous member1050is provided in the container1such that the slope of the bottom face1055of the porous member1050is parallel to the slope of the elastic wave generating device65. A gap is provided between the bottom face1055and the elastic wave generating device65and forms a ink layer1060. Therefore, as the embodiment shown inFIG. 90, when the ink surface in the container1reaches to the lower end of the porous member1050and exists within the ink layer1060, the elastic wave generating device3can detect the ink surface accurately.

In the embodiment shown inFIG. 98, one side face of the porous member, not shown in the figure, is provided in the container1such that the one side face is parallel to the elastic wave generating device66. A gap is provided between the one side face and the side wall1a. In the present embodiment, when ink is filled inside the container1and gap between the one side face of the porous member and the side wall1b, the reflective wave of the elastic wave generated by the elastic wave generating device66does not change. On the other hand, if ink inside the container1is consumed, and the gap between the one side face of the porous member and the side wall1barises, the reflective wave of the elastic wave generated by the elastic wave generating device66gradually changes. Therefore, the elastic wave generating device66can detect the ink consumption status when the ink surface exists within the region of the length Δh2of the elastic wave generating device66. The length of the elastic wave generating device66is 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. Instill 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. 99shows an ink cartridge according to still another embodiment of the present invention. Plural elastic wave generating device65a,65band65con the bottom face1aformed aslope in the vertical direction spaced at an interval are provided in the container1.

Furthermore, a porous member1050is provided inside the container1. A gap is provided between the porous member1050and the elastic wave generating device65a,65b, and65cto form an ink layer1060. By providing the porous member1050inside the container1, the porous member1050prevents the waving or bubbling of ink inside the container1when 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 device65z,65b, and65c. Furthermore, even if the bubble of ink generates, because the porous member1050absorbs the bubble of ink, the bubble does not stay around the elastic wave generating device65a,65b, and65c. The elastic wave generating device65a,65b, and65ccan thereby accurately detect the ink consumption status.

The width of the ink layer1060is 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 device65a,65band65cin the respective mounting positions of the elastic wave generating device65a,65band65cdiffers depending on whether or not the ink is present in the respective positions of the plural elastic wave generating device65a,65band65c. Thus, whether or not the ink is present in the respective mounted position levels of the elastic wave generating device65a,65band65ccan be detected by scanning each elastic generating means (65a,65band65c) and by detecting the traveled time of the reflected wave of the elastic wave in the elastic wave generating device65a,65band65c. 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 device65band65c. Then, the elastic wave generating device65cdetects and judges that the ink is empty while the elastic wave generating device65aand65bdetect 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 device65band65c.

FIG.100andFIG. 101show cross sections of the ink-jet recording apparatus according to still another embodiment of the present invention.

FIG. 100shows a cross section of the ink-jet recording apparatus alone.

FIG. 101is across section of the ink-jet recording apparatus to which the ink cartridge272is mounted. A carriage250capable of reciprocating in the direction of the width of the ink-jet recording paper includes a recording head252in a lower face thereof. The carriage250includes a subtank unit256in an upper face of the recording head252. The subtank unit256has a similar structure to that shown in FIG.92. The subtank unit256has an ink supply needle254facing an ink cartridge272mounting side. In the carriage250, there is provided a convex part258in a manner such that the convex part258is disposed counter to a bottom portion of the ink cartridge272and in an area where the ink cartridge272is to be mounted there above. The convex part258includes an elastic wave generating device260such as the piezoelectric vibrator.

FIG. 102show an embodiment of the ink cartridge suitable for the recording apparatus shown in FIG.100.

FIG. 102shows an embodiment of the ink cartridge for use with a single color, for instance, the black color. The ink cartridge272according to the present embodiment, comprises a container which houses ink and an ink supply port276which comes in contact with an ink supply needle254of the recording apparatus in a sealed manner. In the container274, there is provided the concave part278, positioned in a bottom face274a, which is to be engaged with the convex part258shown in FIG.101. The concave part278houses ultrasound transferring material such as gelated material280.

The ink supply port276includes a packing ring282, a valve body286and a spring284. The packing ring282is engaged with the ink supply needle254in a fluid-tight manner. The valve body286is constantly and elastically contacted against the packing ring282by way of the spring284. When the ink supply needle254is inserted to the ink supply port276, the valve body286is pressed by the ink supply needle254so as to open an ink passage. On an upper wall of the container274, there is mounted a semiconductor memory means288which stores data on ink inside the ink cartridge and so on.

A porous member1050is provided inside the container274. A gap is provided between the porous member1050and the gelated material280to form an ink layer1060. By providing the porous member1050inside the container274, the porous member1050prevents the waving or bubbling of ink inside the container274. Therefore, the elastic wave generating device260can accurately detect the ink consumption status as shown in FIG.90.

As in the embodiment shown inFIG. 90, the present embodiment of the elastic wave generating device260can accurately detect the ink surface when the ink surface inside the container274reaches to the lower end of the porous member1050and exists within the ink layer1060. The width of the gap between the porous member1050and the elastic wave generating device260is not limited. Preferably, the porous member1050is provided vicinity of the elastic wave generating device260.

Referring toFIG. 101, when the ink supply port276of the ink cartridge272is inserted through the ink supply needle254of the subtank unit256, the valve body286recedes against the spring284, SO that an ink passage is formed and the ink inside the ink cartridge272flows into the ink chamber262. At a stage where the ink chamber262is filled with ink, a negative pressure is applied to a nozzle opening of the recording head252so as to fill the recording head with ink. Thereafter, the recording operation is performed. When the ink is consumed in the recording head252by the recording operation, a pressure in the downstream of a flexible valve266decreases. Then, the flexible valve266is positioned away from a valve body270so as to become opened. When the flexible valve36is opened, the ink in the ink chamber262flows into the recording head252through the ink passage35. Accompanied by the ink which has flowed into the recording head252, the ink in the ink cartridge272flows into the subtank unit256.

While the recording apparatus is operating, a drive signal is supplied to the elastic wave generating device260at 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 device260is radiated from the convex part258and is transferred to the ink inside the ink cartridge272by propagating through the gelated material280in the bottom face274aof the ink cartridge272. Though the elastic wave generating device260is provided in the carriage250inFIG. 101, the elastic wave generating device260may be provided inside the subtank unit256.

Since the elastic wave generated by the elastic wave generating device260propagates through the ink liquid, the traveling time of the reflected wave occurring on the ink liquid surface to arrive at the elastic wave generating device260varies 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 device260from the ink liquid surface when the ink liquid surface is excited by the elastic wave generating device260. Moreover, the elastic wave generated by the elastic wave generating device260vibrates 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 device260can 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 cartridge272is not mounted properly to the carriage250, the shape of the elastic wave from the elastic generating means260changes 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 cartridge272.

The traveling time of the reflected wave of the elastic wave generated by the elastic wave generating device260is affected by the density of ink housed in the container274. 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 means288, so that a detection sequence can be set based on the data and thus the ink remaining amount can be further precisely detected.

FIG. 103shows an ink cartridge272according to still another embodiment of the present invention. In the ink cartridge272shown inFIG. 103, the bottom face274ais formed aslope in the vertical direction.

In the ink cartridge272shown inFIG. 103, when the ink remaining amount is becoming low and part of a radiating area of the elastic wave generating device260is exposed from the liquid surface, the traveled time of the reflected wave of the elastic waves generated by the elastic wave generating device260continuously changes corresponding to the change Δh1of the liquid surface. The Δh1denotes change of the height of the bottom face274ain both ends of the gelated material280. 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 device260.

Furthermore, a porous member1050is provided inside the container274. The porous member1050prevents the waving or bubbling of ink inside the container274. Therefore, the elastic wave generating device260can accurately detect the ink consumption status.

The porous member1050is provided in the container274such that the slope of the bottom face1055of the porous member1050is parallel to the slope of the bottom face of the container274. A gap is provided between the bottom face1055and the elastic wave generating device260and forms a ink layer1060.

When ink is filled inside the container274and ink layer1060, the reflective wave of the elastic wave generated by the elastic wave generating device260does not change. On the other hand, if ink inside the container274is consumed, gap arises in the ink layer1060instead of ink. With the arising of the gap in the ink layer1060, the reflective wave of the elastic wave generated by the elastic wave generating device260gradually changes. Therefore, the elastic wave generating device260can detect the ink quantity when the ink status in the container274is near to ink end status. The width of the ink layer1060is not limited as the embodiment shown in FIG.97.

FIG. 104shows an ink cartridge272and an ink-jet recording apparatus according to still another embodiment of the present invention. The ink-jet recording apparatus shown inFIG. 104includes a convex part258′ in a side face274bin an ink supply port276side of the ink cartridge272. The convex part258′ includes an elastic wave generating device260′. Gelated material280′ is provided in the side face274bof the ink cartridge272so as to engage with the convex part258′. According to the ink cartridge272shown inFIG. 104, when the ink remaining amount is becoming low and part of a radiating area of the elastic wave generating device260′ is exposed from the liquid surface, the traveled time of the reflected wave of the elastic waves generated by the elastic wave generating device260′ and the acoustic impedance continuously change corresponding to the change Δh2of the liquid surface. The Δh2denotes difference in the height of both ends of the gelated material280′. 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 device260or change in the acoustic impedance.

The ink cartridge according to the present embodiment further has a porous member1050provided inside the container274. The ink-jet recording apparatus includes a convex part258′ in a side face274bin an ink supply port276side of the ink cartridge272. The convex part258′ includes an elastic wave generating device260′. The side face1056of the porous member1050is parallel to the side face274bof the container274. An ink layer1060is formed on the gap between the side face1056and the elastic wave generating device260′.

The porous member1050prevents the waving or bubbling of ink inside the container274. Therefore, the elastic wave generating device260′ can accurately detect the ink consumption status.

When ink is filled inside the container274and ink layer1060, the reflective wave of the elastic wave generated by the elastic wave generating device260′ does not change. On the other hand, if ink inside the container274is consumed, gap arises in the part corresponding to the Δh2which is a width in the height direction of the gelated material280′ within the ink layer1060. With the arising of the gap in the ink layer1060, the reflective wave of the elastic wave generated by the elastic wave generating device260′ gradually changes. Therefore, the elastic wave generating device260′ can detect the ink consumption status when the is ink surface within the width Δh2in the height direction.

If the ink surface is within the region of the Δh2, the elastic wave generating device260′ can detect the ink surface. According to the ink cartridge according to the present embodiment, there is a gap between the side face1056of the porous member1050and the elastic wave generating device260′, the elastic wave generating device260′ can detect the ink surface within the region of the Δh2even if the porous member1050is provided in the container274. Therefore, by widen the width of the Δh2, the elastic wave generating device260′ can detect the ink surface when ink is filled in the container274until the ink surface when ink in the container274is nearly end.

In the above embodiments, the elastic wave is transmitted and received by the same elastic wave generating device260and260′ 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 device260may 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. 105is 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 inFIG. 105has a actuator106. An ink supply port2which comes in contact with an ink supply needle of the recording apparatus in a sealed manner is provided in a container1which houses the ink. In an outside portion of a bottom face1aof the container1, the actuator106is mounted such that the actuator106can contact with ink inside the container1via the through hole1cprovided in the container1. 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 actuator106can change from the liquid to the gas, the actuator106is provided in a slightly upward position from the ink supply port2. Moreover, an actuator106may be separately provided instead, so that the actuator106is used as an means for detecting liquid only.

Furthermore, a porous member1050is provided inside the container1. The porous member1050is provided around the actuator106inside the container1. A gap having a same depth with the through hole1cis provided between the porous member1050and the actuator106. By providing the porous member1050inside the container1, the porous member1050prevents the waving or bubbling of ink inside the container1when 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 actuator106. The actuator106can thereby detect the ink consumption status accurately.

Moreover, the width of the gap between the porous member1050and the actuator106is not limited. To suppress the bubbling of ink as much as possible, the width of ink layer1060is reduced by providing the porous member1050on lower side of the container1. If the width of the ink layer1060is small, the actuator106can detect the ink quantity only when the ink status is near to the ink end. However, ink does not wave inside the container1. Therefore, the actuator106can accurately detect the ink quantity when the ink consumption status is near to the ink end status. Therefore, the porous member1050is preferably located nearby the actuator106without limiting the width of gap between the porous member1050and the actuator106.

Furthermore, the hole diameter of porous member1050is set such that the porous member1050does not absorbs ink existed in the through hole1cbefore the ink surface reaches to the through hole1c. In other words, the porous member1050is designed such that the capillary force works in the porous member1050is smaller than the capillary force which can hold ink in the container1. Therefore, ink does not remain in the porous member1050by its own weight and exists in the through hole1cwhen the ink inside the container1is in an ink near end status. Furthermore, an airhole, not shown in the figure, is provided on the container1. The airhole is provided on the upper side of the container1to communicate with outside of container1. Air is introduced inside the container1by the airhole, and ink flows downward by own weight with advance of ink consumption. The residual ink thereby stays in the through hole1c.

On the other hand, the hold diameter of the porous member1050can be set such that the porous member1050absorbs ink existed in the through hole1cwhen the predetermined amount of the ink is consumed. That is, the hole diameter of the porous member1050is set that the capillary force works in the porous member1050is equal to or larger than the capillary force which can hold ink inside the container1. The porous member1050thereby absorbs ink existed in the through hole1cwhen the predetermined amount of ink inside of the container1is consumed. Furthermore, the hole diameter of the porous member1050of a part nearby the ink supply port2is made smaller than the hole diameter of the other part of the porous member1050. Ink existed in the through hole1cis thereby absorbed by the porous member1050and further supplied to the ink supply port2from the porous member1050.

For example, the hole diameter of the porous member1050is designed such that the porous member1050absorbs ink remained in the through hole1cwhen the ink quantity in the ink cartridge becomes small amount in a degree that printing becomes defective. Furthermore, the hole diameter of the porous member1050is designed such that the porous member1050can send the ink, which is absorbed from the through hole1cby the porous member1050, to the ink supply port2. The actuator106can 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 member1050nearby the actuator106is made larger than the hole diameter of the porous member1050around the ink supply port2.

The porous member1050occupies more than half of the volume of the container1. However, a relatively small porous member, not shown in the figure, can be provided only around the actuator106.

FIG. 106is 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 hole1con the bottom face1aof the container1, which contains ink. The bottom part of the through hole1cis closed by the actuator650and forms an ink storing part.

The ink cartridge according to the present embodiment has a porous member1050provided inside the through hole1c. The porous member1050thereby contacts with the vibrating region of the actuator650. By providing the porous member1050to contact with the vibrating region of the actuator650, ink does not remained in the through hole1c.

For example, the hole diameter of the porous member1050bprovided around the through hole1cis made smaller than the hole diameter of the porous member1050aprovided inside the through hole1c. The capillary force of the porous member1050aaround the through hole1cthereby becomes smaller than the capillary force of the porous member1050ainside of the through hole1c. Therefore, ink contained in the porous member1050ainside the through hole1cis absorbed by the porous member1050bprovided around the through hole1cwhen the ink inside the ink cartridge is consumed. Thus, ink does not remain in the through hole1c. Therefore, the accuracy of detecting the ink consumption status inside the ink cartridge by the actuator650can be improved.

FIG. 107is 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.105andFIG. 106. Acarriage30capable of reciprocating in the direction of the width of the recording paper is equipped with a subtank unit33, while the recording head31is provided in a lower face of the subtank unit33. Moreover, the ink supply needle32is provided in an ink cartridge mounting face side of the subtank unit33.

While the recording apparatus is operating, a drive signal is supplied to the actuator106at a detection timing which is set in advance, for example, at a certain period of time.

By adhering the actuator106to the container1, a process of embedding electrodes for use in detecting the liquid surface is unnecessary in the course of forming the container1. 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. 108is a cross sectional view of another embodiment of a subtank unit33. The subtank unit33shown inFIG. 108comprises the actuator106and a porous member1050. In the embodiment shown inFIG. 27, the actuator106and the porous member1050are provided in the container1of the ink cartridge. However, as shown inFIG. 108, the actuator106and the porous member1050can be provided inside the subtank unit33. Furthermore, the actuator106and the porous member1050can be provided in both of inside the container1of the ink cartridge and the subtank unit33.

According to the embodiment shown inFIG. 108, the actuator106can detect the ink quantity and the existence of ink inside the subtank unit33. Furthermore, the porous member1050can prevents the waving and bubbling of ink inside the subtank unit33. Therefore, the actuator106can accurately detects the ink quantity and the existence of ink. Moreover, because the actuator106is provided inside the subtank unit33, the actuator106can detect the ink quantity and the existence of ink inside the subtank unit33even 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 actuator106and the porous member1050are provided on both inside of the container1of the ink cartridge and the subtank unit33, the actuator106can detect the ink consumption status more accurately. Furthermore, the actuator106can detect the timing of ink end inside the container1of the ink cartridge.

FIG. 109show ink cartridges according to still another embodiments of the present invention. In an embodiment shown inFIG. 109, a actuator106is mounted in a bottom face1aformed a slope in the vertical direction.

According to the embodiments shown inFIG. 109, when part of the actuator106is exposed from the liquid surface, the residual vibration of the actuator106continuously changes. Therefore, the actuator106can accurately detect the ink consumption quantity by detecting the change of the acoustic impedance. For example, the actuator106can detect the ink surface while the ink surface exists within the region of the Δh1shown in FIG.109.

In the embodiment, the porous member1050is provided in the container1. The porous member1050prevents the waving and bubbling of ink inside the container1. The porous member1050thereby improves the accuracy of detecting the ink quantity by the actuator106.

In the embodiment shown inFIG. 109, the porous member1050is provided nearby the actuator106. However, the present embodiment does not provide the porous member1050inside the through hole1c. Therefore, ink directly contacts with the vibration region of the actuator106. Thus, the vibration region of the actuator106exposed to air with the increase in consumption of ink. Then, the vibration status at the vibration region of the actuator106changes. Therefore, to detect the ink quantity by the actuator106becomes easy.

To suppress the waving and bubbling of ink as much as possible, it is not preferable to have a gap between the porous member1050and the actuator106. On the other hand, it is also not preferable that the porous member1050adhere to the vibrating region of the actuator106in a degree that the vibrating section of the actuator106cannot vibrate. Therefore, the porous member1050is preferable to provided around the vibrating region of the actuator106. However, the porous member1050can be contacts with the vibrating region of the actuator106if the vibrating region of the actuator106can vibrate and detect the ink existence and the ink quantity.

FIG. 110shows an ink cartridge according to still another embodiment of the present invention. Plural actuators106a,106b, and106con the bottom face1aformed a slope in the vertical direction spaced at an interval are provided in the container1. Furthermore, a porous member1050is provided inside the container1. The porous member1050prevents the actuators106a,106b, and106cto 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 actuators106a,106b, and106c, the amplitude of the residual vibration and a resonant frequency of the each of the actuators106a,106b, and106cdiffers at each of the mounting position of the actuators106a,106b, and106c. Therefore, the existence of ink at the level of the mounting position of each of the actuators106a,106b, and106ccan be detected by measuring the counter electromotive force of the residual vibration of each of the actuators106a,106b, and106c. Therefore, residual quantity of ink can be detected step by step. For example, if the ink surface is at the level between the actuator106band the actuator106c, the actuator106adetects non-ink status, and the other actuators106band106cdetects ink-exist status. By comprehensively judging these detecting results, it can be known that the ink surface positions between the mounting position of the actuator106band actuator106c.

FIG. 111shows other embodiment of the through hole1c.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 hole1c, and the right hand side of the figure shows the status that ink K is remained in the through hole1c. In the embodiment ofFIG. 28, the side face of the through hole1cis formed as the vertical wall. In FIG.111(A), the side face1dof the through hole1cis slanted in vertical direction and opens with expanding to the outside. In FIG.111(B), a stepped portion1eand1fare formed on the side face of the through hole1c. The stepped portion1f,which is provided above the stepped portion1e,is wider than the stepped portion1e.In FIG.111(C), the through hole1chas a groove1gthat extends to the direction in which ink is easily discharged, that is, the direction to a ink supply port2.

According to the shape of the through hole1cshown 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.22andFIG. 23, the vibration characteristic of the actuator650at 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 container1, and thus the ink end status can be reliably detected.

Furthermore, in the ink cartridge of the present embodiment, a porous member, not shown inFIG. 111, is provided around the through hole1cof the FIG.111(A), FIG.111(B), and FIG.111(C). The porous member1050becomes easy to absorb ink inside the through hole1cby forming the side face1d,stepped portion1e,and1f,or groove1g.

FIG. 112is a slant view of the further other embodiment of the actuator. In this embodiment, the actuator670comprises a concave part forming base plate80and a piezoelectric element82. The concave part81is formed on the one side of the face of the concave part forming base plate80by the technique such as etching, and piezoelectric element82is mounted on the other side of the face of the concave part forming base plate80. The bottom portion of the concave part81operates as a vibrating region within the concave part forming base plate80. Therefore, the vibrating region of the actuator670is determined by the periphery of the concave part81. Furthermore, the actuator670has the similar structure with the structure of the actuator106shown inFIG. 22, in which the base plate178and the vibrating plate176is 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 actuator670has a size which can be embedded into the through hole1cprovided on the container1. By this embedding process, the concave part81can operates as the cavity. The actuator106shown inFIG. 22can be formed to be embedded into through hole1cas actuator670shown in FIG.112. Furthermore, a porous member1050is provided around the actuator670.

The actuator106of the ink cartridge180B shown inFIG. 113is mounted on the side wall of the supply port of the ink container194. The actuator106can be mounted on the side wall or bottom face of the ink container194if the actuator106is mounted nearby the ink supply port187. The actuator106is preferably mounted on the center of the width direction of the ink container194. Because ink is supplied to the outside through the ink supply port187, ink and actuator106reliably contacts until the timing of the ink near end by providing the actuator106nearby the ink supply port187. Therefore, the actuator106can reliably detect the timing of the ink near end. A porous member1050is provided around the actuator106. The porous member1050prevents the waving and the bubbling of ink and thereby prevents the actuator106to wrongly detect the ink consumption status.

Furthermore, by providing the actuator106nearby the ink supply port187, the setting position of the actuator106to 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 actuator106becomes reliable by arranging the actuator nearby the ink supply port. Furthermore, the actuator106can be further reliably positioned by mounting the actuator106at the center of the width direction of the ink container194. 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. 114shows further other embodiment of the ink cartridge180.FIG. 114shows a cross section of an ink cartridge180C. The semiconductor memory device7and the actuator106are formed on the same circuit board610in the ink cartridge180C.

FIG. 115shows further other embodiment of the ink cartridge180. A plurality of actuators106is mounted on the side wall194bof the ink container194in the ink cartridge180D shown in FIG.115. It is preferable to use the plurality of the actuators106which is formed in one body as shown inFIG. 26for these plurality of actuators106. The plurality of actuators106is arranged on the side wall194bwith interval in vertical direction. By arranging the plurality of actuators106on the side wall194bwith interval in vertical direction, the residual quantity of ink can be detected step by step.

The ink cartridge180E shown inFIG. 115mounts a actuator606which is long in vertical direction on the side wall194bof the ink container194. The change of the residual quantity of ink inside the ink container194can be detected continuously by the actuator606which is long in vertical direction. The length of the actuator606is preferably longer than the half of the height of the side wall194b. InFIG. 115, the actuator606has the length from the substantially from the top end to the bottom end of the side wall194b.

The ink cartridge180F shown inFIG. 115mounts a plurality of actuators106on the side wall194bof the ink container194as the ink cartridge180D shown in FIG.115. The ink cartridge180F further comprises the wave preventing wall192, which is long in vertical direction, along the side wall194bwith predetermined space with the side wall194bsuch that the wave preventing wall192faces directly to the plurality of actuators106. It is preferable to use the plurality of the actuators106which is formed in one body as shown inFIG. 26for these plurality of actuators106. A gap which is filled with ink is formed between the actuator106and the wave preventing wall192. Moreover, the gap between the wave preventing wall192and the actuator106has a space such that the gap does not hold ink by capillary force. When the ink container194is rolled, ink wave is generated inside the ink container194by the rolling, and there is possibility that the actuator106malfunctions by detecting gas or an air bubble caused by the shock of the ink wave. By providing the wave preventing wall192, ink wave around the actuator106can be prevented so that the malfunction of the actuator106can be prevented. The wave preventing wall192also prevents the air bubble generated by the rolling of ink to enter to the actuator106.

Furthermore, a porous member1050is provided around the actuator106in the embodiments shown in FIG.115(A), FIG.115(B), and FIG.115(C). The porous member1050prevents the waving or bubbling of ink and prevents the actuator106to wrongly detect the ink consumption status.

The embodiment that the actuator106is 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 actuator106can be mounted on the ink tank which is mounted on the inkjet recording apparatus together with a carriage and formed together with a carriage as one body. Furthermore, the actuator106can 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.