Patent Publication Number: US-7581808-B2

Title: Liquid container

Description:
BACKGROUND 
   1. Technical Field 
   The present invention relates to a liquid container that supplies liquid retained in a liquid container body thereof to a liquid consumption apparatus. 
   2. Related Art 
   An ink cartridge containing ink inside thereof and an ink-jet recording apparatus to which such an ink cartridge is attached as a removable unit is a well known example set of a liquid container and a liquid consumption apparatus. 
   Inside the container body thereof which is detachably attached to the cartridge attachment unit of an ink-jet recording apparatus, a known ink cartridge has as its typical configuration ink-containing chambers (i.e., rooms or compartments) in which ink is retained, an ink supply port that is provided to supply the ink retained in the ink-containing chambers to the ink-jet recording apparatus, and an ink flow channel through which the ink-containing chambers communicate with the ink supply port. Such a known ink cartridge is configured to supply ink retained therein to the ink-jet recording apparatus through an ink supply needle that is provided on the cartridge attachment unit of the ink-jet recording apparatus when the ink cartridge is attached to the cartridge attachment unit thereof in such a manner that the ink supply needle of the cartridge attachment unit is inserted through the ink supply port of the ink cartridge. 
   Generally speaking, air bubbles often form in ink retained in an ink cartridge due to a temperature change during long-term storage, vibrations generated during shipping, or some other reason. These air bubbles deteriorate the ink-supply characteristics of the affected ink cartridge that is attached to an ink-jet recording apparatus, which could result in poor print quality. In order to suppress the forming of air bubbles inside an ink cartridge, as a known technique, an ink cartridge is vacuum packed immediately after its production so as to seal the periphery of the container body thereof as a pressure-reduced space. As a further technical insurance for prolonged storage, JP-A-2000-33709 proposes a technique to prolong the efficacy of reduced pressure in a vacuum-packed ink cartridge for a long time. Specifically, it is described in the above-identified publication that a concave portion, which is formed in the outer surface of the top cover of the container body of an ink cartridge that has ink-containing chambers, is utilized as a deaeration chamber, that is, a space into which any remaining air can be expelled, which contains/accumulates negative pressure for deaeration when the ink cartridge is subjected to vacuum packing. 
   In order to prevent the recording head of an ink-jet recording apparatus from performing “empty-cartridge printing” after the attached ink cartridge has run out of ink retained therein, some of ink-jet recording apparatuses have an ink remaining amount detection sensor that outputs a predetermined electric signal when the remaining amount of ink retained in the container body thereof reaches a certain predefined threshold. As described in JP-A-2001-146019, some of recently developed ink cartridges are provided with such an ink remaining amount detection sensor that is made up of a cavity that forms a part of an ink flow channel, a diaphragm that constitutes a part of the wall surface of the cavity, and a piezoelectric element that is provided on the diaphragm. In this type of recent ink cartridge, the remaining amount of ink is detected on the basis of a change in residual vibration in response to a vibration applied to the diaphragm. 
   Very small air bubbles could sometimes form (and remain) when, for example, ink is filled at a factory in the ink-containing chambers inside the container body during a production process of an ink cartridge. Disadvantageously, in an ink cartridge of related art that is provided with an ink remaining amount detection sensor, there is no way to remove air bubbles that formed at the time of filling of ink. Therefore, the air bubbles could remain in the cavity of the ink remaining amount detection sensor. If any air bubbles remain, there is a possibility that an erroneous detection of an ink-absent state could occur although there is still a sufficient amount of ink left inside at the time of starting the use of the ink cartridge. This erroneous detection occurs because the remaining air bubbles affect residual vibration. 
   SUMMARY 
   In order to address the problems described above without any limitation thereto, the present invention provides a liquid container that is provided with a liquid remaining amount detection sensor that detects the presence/absence of the liquid retained in the container body of the liquid container by utilizing residual vibration, where the liquid container according to the invention is capable of removing air bubbles if they formed during a liquid-filling production step at a factory and remain in the cavity of the liquid remaining amount detection sensor, thereby making it possible to prevent the liquid remaining amount detection sensor from performing erroneous detection attributable to the remaining air bubbles. 
   The invention provides a solution to the above-described problems without any limitation thereto by providing (1) a liquid container having a container body that can be detachably attached to a liquid consumption apparatus, where the container body of the liquid container includes: a liquid containing chamber that retains liquid; a liquid supply hole that is provided to supply the liquid retained in the liquid containing chamber to the liquid consumption apparatus; a liquid flow channel through which the liquid containing chamber is in communication with the liquid supply hole; a liquid remaining amount detection sensor having a cavity that constitutes a part of the liquid flow channel, a diaphragm that constitutes a part of a wall surface of the cavity, and a piezoelectric element that applies a vibration to the diaphragm, the liquid remaining amount detection sensor detecting the presence or absence of liquid in the liquid flow channel on the basis of residual vibration in response to the vibration applied to the diaphragm; and a no-liquid-filled empty chamber that is in communication with the outside of the container body, the empty chamber with no liquid filled therein becoming a deaeration chamber that contains and/or accumulates negative pressure for deaeration when the liquid container is subjected to vacuum packing. 
   With the configuration described above, even in a case where small air bubbles has formed in the cavity of the liquid remaining amount detection sensor during an ink-filling step of liquid-container production at a factory, such small air bubbles remaining in the cavity of the liquid remaining amount detection sensor dissolve into liquid and thus disappear thanks to the action of deaeration negative pressure that expels any remaining air out of the liquid container when the liquid container is subjected to vacuum packing. Moreover, deaeration negative pressure applied at the time of vacuum packing is contained/accumulated in the no-liquid-filled chamber (i.e., empty chamber) in such a manner that the no-liquid-filled chamber of the container body functions as a pressure reduction space that causes any air bubbles remaining in the container body to be dissolved to disappear effectively up to the time when a user opens the package of the liquid container. Therefore, the invention provides the liquid container that is capable of removing air bubbles that remain in the liquid remaining amount detection sensor with a greater certainty, thereby making it possible to prevent the liquid remaining amount detection sensor from performing erroneous detection attributable to the remaining air bubbles. 
   (2) In the liquid container having the configuration described above, it is preferable that the empty chamber having no liquid filled therein has a dimension larger than the liquid containing chamber. With the configuration described in (2) above, a comparatively large amount of negative pressure for deaeration is contained/accumulated in the no-liquid-filled empty chamber. This makes it possible to maintain a liquid container contained in a vacuum-packed package in a good pressure-reduced environment until a user opens the package thereof, thereby making it possible to prolong the efficacy of reduced pressure in removing air bubbles in the vacuum-packed liquid container for a long time. Thus, the configuration of the liquid container according to the invention makes it possible to further improve the shelf life of a vacuum-packed liquid container. 
   (3) In the liquid container having the configuration described above, it is preferable that the empty chamber having no liquid filled therein is formed at a plurality of positions in the container body in a distributed layout. With the configuration described in (3) above, the pressure-reducing action of deaeration negative pressure that is contained/accumulated in the empty chamber having no liquid filled therein works at the plurality of positions in the container body. This ensures, advantageously, that the pressure-reducing action of deaeration negative pressure, which is effective for removing air bubbles, works in a wider area of the container body in a more uniform manner. In addition, such pressure-reducing action works multi-directionally (i.e., from a relatively large number of directions) on the position at which air bubbles have formed. For these reasons, it is possible to remove air bubbles with a greater efficiency. 
   (4) It is preferable that the liquid container having the configuration described above further includes: an air intake channel through which air that has been taken in from the outside flows to reach the liquid containing chamber in accordance with the consumption amount of the liquid retained in the liquid containing chamber; an air chamber that is formed by enlarging the dimension of a certain halfway point en route on the air intake channel; and a stopper (such as a film to be removed) that blocks, in a vacuum-packed state, the air intake channel at a relatively upstream position in comparison with the air chamber. With the configuration described in (4) above, when any liquid retained in the liquid containing chamber flows back through the air intake channel during use of the liquid container due to thermal expansion, external vibration, or any other reason, it is possible to prevent the back-flowed liquid from leaking out because the air chamber formed en route on the air intake channel functions as a liquid-trap space so as not to pass the back-flowed liquid therethrough. Since the stopper blocks the air intake channel in a vacuum-packed state, it is possible to ensure that liquid does not leak out of the air intake hole. 
   (5) In the liquid container having the configuration described above, it is preferable that the empty chamber having no liquid filled therein has a dimension larger than the air chamber. If such a configuration is adopted, generally speaking, a higher deaeration performance is required for removing air bubbles because the amount of air remaining in the container body increases by the dimension of the air chamber. In this respect, with the configuration described in (5) above, since the dimension of the empty chamber having no ink filled therein is configured to be larger than that of the air chamber, it is possible to easily maintain high deaeration performance. With an assured high deaeration performance, the invention makes it possible to remove air bubbles that remain in the liquid remaining amount detection sensor with a greater reliability. 
   (6) In the liquid container having the configuration described above, it is preferable that the empty chamber having no liquid filled therein is formed adjacent to the liquid containing chamber and the air chamber. With the configuration described in (6) above, it is possible to ensure a relatively large active area for deaeration action of negative pressure which works via a partition wall interposed between the empty chamber having no liquid filled therein and the liquid containing chamber formed adjacent thereto and also works via a partition wall interposed between the empty chamber having no liquid filled therein and the air chamber formed adjacent thereto. Having such a structure, the liquid container according to the invention makes it possible to improve the deaeration efficiency inside the container body so as to remove air bubbles that remain in the liquid remaining amount detection sensor with a greater reliability. Thus, the liquid container according to the invention makes it possible to prevent the liquid remaining amount detection sensor from performing erroneous detection that could be caused by the remaining air bubbles. 
   (7) In the liquid container having the configuration described above, it is preferable that the empty chamber having no liquid filled therein is formed adjacent to the liquid containing chamber that is formed in the proximity of the cavity of the liquid remaining amount detection sensor. With the configuration described in (7) above, the deaeration efficiency inside the cavity of the sensor is further increased. Therefore, the invention provides the liquid container that is capable of removing air bubbles that remain in the liquid remaining amount detection sensor with a greater certainty, thereby making it possible to prevent the liquid remaining amount detection sensor from performing erroneous detection attributable to the remaining air bubbles. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
       FIG. 1  is an external perspective view that schematically illustrates an ink cartridge as a first exemplary embodiment of the invention. 
       FIG. 2  is an opposite-side external perspective view that schematically illustrates the ink cartridge according to the first embodiment of the invention, which is viewed in the reverse direction thereof. 
       FIG. 3  is an exploded perspective view of the ink cartridge according to the first embodiment of the invention. 
       FIG. 4  is an opposite-side exploded perspective view of the ink cartridge according to the first embodiment of the invention, which is viewed in the reverse direction thereof. 
       FIG. 5  is a diagram that schematically illustrates the ink cartridge according to the first embodiment of the invention that is attached to an ink-jet recording apparatus. 
       FIG. 6  is a sectional view of the ink cartridge according to the first embodiment of the invention that is viewed immediately before attachment to a carriage. 
       FIG. 7  is a sectional view of the ink cartridge according to the first embodiment of the invention that is viewed immediately after attachment to the carriage. 
       FIG. 8  is a front view of the ink cartridge according to the first embodiment of the invention. 
       FIG. 9  is a rear view of the ink cartridge according to the first embodiment of the invention. 
       FIG. 10A  is a simplified diagram that corresponds to  FIG. 8 , whereas  FIG. 10B  is a simplified diagram that corresponds to  FIG. 9 . 
       FIG. 11  is a sectional view taken along the line A-A′ of  FIG. 8 . 
       FIG. 12  is a conceptual diagram that explains the route structure of the fluid channels illustrated in  FIG. 8 . 
       FIG. 13  is a front view of the ink cartridge according to the second embodiment of the invention. 
       FIG. 14  is a front view of the ink cartridge according to the third embodiment of the invention. 
       FIG. 15  is a rear view of the ink cartridge illustrated in  FIG. 14 . 
   

   DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   With reference to the accompanying drawings, preferred embodiments of a liquid container according to the present invention are explained in detail below. In the following exemplary embodiment of the invention, an ink cartridge, which is attachable to an ink-jet recording apparatus (printer), is taken as an example of various kinds of liquid containers. An ink-jet recording apparatus is taken as an example of various kinds of liquid ejection apparatuses in the following description. 
     FIG. 1  is an external perspective view that schematically illustrates an ink cartridge as a first exemplary embodiment of a liquid container according to the present invention.  FIG. 2  is an “opposite-side” external perspective view that schematically illustrates the ink cartridge according to the present embodiment of the invention, which is viewed in the reverse direction thereof.  FIG. 3  is an exploded perspective view of the ink cartridge according to the present embodiment of the invention, whereas  FIG. 4  is an opposite-side exploded perspective view of the ink cartridge according to the present embodiment of the invention, which is viewed in the reverse direction thereof.  FIG. 5  is a diagram that schematically illustrates the ink cartridge according to the present embodiment of the invention that is attached to a carriage.  FIG. 6  is a sectional view of the ink cartridge according to the present embodiment of the invention that is viewed immediately before attachment to the carriage.  FIG. 7  is a sectional view of the ink cartridge according to the present embodiment of the invention that is viewed immediately after attachment to the carriage. 
   As illustrated in  FIGS. 1 and 2 , an ink cartridge  1  according to the present embodiment of the invention is a liquid container having the shape of, approximately, a rectangular parallelepiped. The ink cartridge  1  according to the present embodiment of the invention contains ink in ink-containing chambers provided inside thereof. As illustrated in  FIG. 5 , the ink cartridge  1  is attached to a carriage  200  of an ink-jet recording apparatus, which is explained herein as an example of various kinds of liquid consumption apparatuses. The ink cartridge  1  supplies ink to the ink-jet recording apparatus. 
   The external features of the ink cartridge  1  are described below. As illustrated in  FIGS. 1 and 2 , the ink cartridge  1  has a flat top surface  1   a . An ink supply hole  50 , which is used to supply ink to an ink-jet recording apparatus when the ink cartridge  1  is attached to the ink-jet recording apparatus, is provided on a bottom surface  1   b , which is at the opposite side of the top surface  1   a . As illustrated in  FIG. 4 , an air intake hole  100 , which takes air from the outside into the ink cartridge  1 , is formed on the bottom surface  1   b . In other words, the ink cartridge  1  is configured as an air-open type ink cartridge that supplies ink through the ink supply hole  50  while taking in air through the air intake hole  100 . 
   As illustrated in  FIG. 6 , in this embodiment of the invention, the air intake hole  100  has a concave portion  101  and a small hole  102 . The concave portion  101  is an approximately cylindrical cavity that is formed in the bottom surface  1   b  in a direction toward the top surface  1   a . The small hole  102  is formed in the inner circumference surface of the concave portion  101 . The small hole  102  is in communication with an air intake channel/passage that will be described later. The outside air is taken in through the small hole  102  to finally reach the most upstream ink-containing chamber  370 . 
   The concave portion  101  of the air intake hole  100  is formed to have a depth that is large enough to accommodate a projection  230  formed on the carriage  200 . The projection  230  is provided to remind a user to remove a sealing film  90  if they forgot to do so. The sealing film  90  functions as a stopper that seals the air intake hole  100  in an airtight state. Since the projection  230  does not get inserted into the air intake hole  100  without removing the sealing film  90  in advance, it is impossible to attach the ink cartridge  1  to the carriage  200  if the sealing film  90  remains adhered thereto. By this means, since the projection structure makes it impossible for a user to attach the ink cartridge  1  to the carriage  200  if the sealing film  90  is still adhered to cover the air intake hole  100 , it is ensured that a user is reminded to remove the sealing film  90  at the time of attachment of the ink cartridge  1  to the carriage  200 . 
   As illustrated in  FIG. 1 , a “wrong-insertion-prevention” projection  22  is provided on the narrow side surface  1   c  of the ink cartridge  1 , which is perpendicularly adjacent to the top surface  1   a  thereof across its one short edge. The wrong-insertion-prevention projection  22  prevents the ink cartridge  1  from being attached to any incorrect attachment position. As illustrated in  FIG. 5 , a patterned indented structure  220 , which is configured to fit with the wrong-insertion-prevention projection  22  if they match, is provided on the carriage  200 , which accommodates the ink cartridge  1 . With such a mating structure, the ink cartridge  1  is successfully attached to the carriage  200  only when the wrong-insertion-prevention projection  22  fits with the patterned indented structure  220 . Depending on the types of ink, the shapes of the wrong-insertion-prevention projection  22  vary from one to another. The patterned indented structure  220  formed on the carriage  200  has likewise shapes that vary from one to another depending on the types of ink. Therefore, even when the carriage  200  is configured such that a plurality of ink cartridges  1  are attachable to the carriage  200  as illustrated in  FIG. 5 , the attachment of any ink cartridge to a wrong attachment position does not occur. 
   As illustrated in  FIG. 2 , a latch-engaging lever  11  is provided on another narrow side face  1   d  of the ink cartridge  1 , which is the opposite side of the narrow side surface  1   c  thereof. The latch-engaging lever  11  has a projection  11   a  that hooks on a concave portion  210  formed on the carriage  200  when the ink cartridge  1  is attached to the carriage  200 . At the time of attachment of the ink cartridge  1  to the carriage  200 , the latch-engaging lever gets temporarily deflected once so as to allow the engagement of the projection  11   a  with the concave portion  210 . By this means, the position of the ink cartridge  1  is fixed with respect to the carriage  200 . 
   A circuit substrate  34  is provided at an area below the latch-engaging lever  11 . The circuit substrate  34  has a plurality of electric connection terminals  34   a  formed thereon. The ink cartridge  1  is electrically connected to an ink-jet recording apparatus when these electric connection terminals  34   a  mechanically/physically contact an electric connection member provided on the carriage  200 , which is not specifically shown in the drawing. A data-rewritable non-volatile memory, which is not specifically shown in the drawings, is provided on the circuit substrate  34 . Having such a non-volatile memory therein, various items of information on the ink cartridge  1  and/or ink use status information on the ink-jet recording apparatus, without any limitation thereto, is stored in the circuit substrate  34 . As illustrated in  FIGS. 3 and 4 , an ink remaining amount detection sensor (sensor unit)  31  that detects the remaining amount of ink retained in the ink cartridge  1  by utilizing residual vibration is provided at the rear side of the circuit substrate  34 . The ink remaining amount detection sensor  31  is a specific example of a liquid remaining amount detection sensor. In the following explanation, the ink remaining amount detection sensor  31  and the circuit substrate  34  are collectively referred to as ink end sensor  30 . 
   As illustrated in  FIG. 1 , a label  60   a  that indicates the contents of an ink cartridge is pasted on the top surface  1   a  of the ink cartridge  1 . The label  60   a  is constituted as an end portion of an outer surface film  60 . Specifically, the outer surface film  60  covers a wide side surface  1   f  of the ink cartridge  1  to further extend onto the top surface  1   a  thereof, where the extended portion thereof overlying the top surface  1   a  constitutes the label  60   a.    
   As illustrated in  FIGS. 1 and 2 , each of the wide side surfaces  1   e  and  1   f  of the ink cartridge  1  that are perpendicularly adjacent to the top surface  1   a  thereof across two long edges thereof is configured as a flat plane. In the following explanation, for convenience, the wide side surface  1   e  is referred to as the front face or front side of the ink cartridge  1 , whereas the wide side surface  1   f  is referred to as the rear face or rear side thereof. In addition, the narrow side surface  1   c  is referred to as the right face or right side thereof, whereas the narrow side surface  1   d  is referred to as the left face or left side thereof. 
   Next, with reference to  FIGS. 3 and 4 , parts/components of the ink cartridge  1  are explained below. 
   The ink cartridge  1  includes a cartridge body  10 , which is a container body, and a cover member  20  that covers the front face of the cartridge body  10 . 
   The cartridge body  10  has ribs  10   a , which have a variety of shapes, on the front face thereof. Functioning as inner-wall partitions, these ribs  10   a  demarcate the inner space at the front side of the cartridge body  10  into a plurality of ink-containing chambers (liquid-containing chambers/rooms) in which ink is retained, an empty chamber in which no ink is filled, air chambers which are formed at certain halfway points en route on an air intake channel/passage  150 , which will be described later. A film  80  is provided between the cartridge body  10  and the cover member  20  to cover the front face of the cartridge body  10 . Specifically, the film  80  covers the open top area of the ribs  10   a , concave portions, and grooves so as to form the ink-containing chambers, empty chamber (i.e., no-ink-filled chamber), air chambers as well as a plurality of fluid channels (i.e., liquid/air flow channels). 
   A differential pressure regulation valve accommodating chamber  40   a , which is a concave portion provided to accommodate a differential pressure regulation valve  40 , and an air/liquid separation chamber  70   a , which is a concave portion that constitutes a part of an air/liquid separation filter  70 , are formed on the rear face of the cartridge body  10 . 
   A valve member  41 , a spring  42 , and a spring washer structure  43  are assembled into the differential pressure regulation valve accommodating chamber  40   a  so as to make up the differential pressure regulation valve  40 . The differential pressure regulation valve  40  is provided between the ink supply hole  50 , which is provided at the downstream side thereof, and the ink-containing chamber, which is provided at the upstream side thereof. The differential pressure regulation valve  40  reduces the pressure of the downstream side thereof in comparison with the upstream side thereof so as to ensure that ink to be supplied to the ink supply hole  50  has negative pressure. 
   An air/liquid separation film  71  is adhered to the bank portion  70   b  that forms the inner peripheral edge of the air/liquid separation chamber  70   a  so as to cover the open top area of the air/liquid separation chamber  70   a . The air/liquid separation film  71 , which constitutes a part of the air/liquid separation filter  70 , is made of a material that passes air but shuts off liquid. As illustrated in  FIG. 10B , the air/liquid separation filter  70  is provided en route on the air intake channel  150  through which the air intake hole  100  communicates with the ink-containing chambers. The air/liquid separation filter  70  functions to prevent any ink retained in the ink-containing chambers from flowing backward through the air intake channel  150  to flow out of the air intake hole  100 . 
   In addition to the differential pressure regulation valve accommodating chamber  40   a  and the air/liquid separation chamber  70   a , a plurality of grooves  10   b  are formed at the rear side of the cartridge body  10 . The outer surface film  60  covers the entire open rear area of the cartridge body  10  to seal the differential pressure regulation valve  40  and the air/liquid separation filter  70  configured as described above as well as each of the exposed grooves  10   b . The covered grooves constitute the air intake channel/passage  150  and ink flow channels. 
   As illustrated in  FIG. 4 , a sensor accommodating chamber  30   a  is formed on the right face of the cartridge body  10 . The sensor accommodating chamber  30   a  is configured as a concave portion that accommodates parts that make up an ink end sensor  30 . The ink remaining amount detection sensor  31 , and a compression spring  32  that presses the ink remaining amount detection sensor  31  against the inner wall of the sensor accommodating chamber  30   a  for fixation thereof, are assembled into the sensor accommodating chamber  30   a . A cover member  33  is then attached so to cover the sensor accommodating chamber  30   a . A circuit substrate  34  is mounted on the outer surface  33   a  of the cover member  33 . The sensor unit of the ink remaining amount detection sensor  31  is connected to the circuit substrate  34 . 
   The ink remaining amount detection sensor  31  has a cavity that constitutes a part of the ink flow channel through which the ink-containing chambers communicate with the ink supply hole  50 , a diaphragm that constitutes a part of the wall surface of the cavity, and a piezoelectric element (piezoelectric actuator) that applies a vibration to the diaphragm. The ink remaining amount detection sensor  31  detects the presence/absence of ink in the ink flow channel on the basis of residual vibration in response to the vibration applied to the diaphragm. That is, the ink remaining amount detection sensor  31  detects the presence/absence of ink in the cartridge body  10  on the basis of differences in the amplitude, frequency, or the like of residual vibration between ink and air. Specifically, when ink retained in the ink-containing chamber of the cartridge body  10  is consumed to cause air to be taken in the ink-containing chamber and then to flow through the ink flow channel to go into the cavity of the ink remaining amount detection sensor  31 , the ink remaining amount detection sensor  31  detects the entering of air into its cavity on the basis of changes in the amplitude and/or frequency of residual vibration, and then outputs an electric signal that indicates an ink end. 
   As illustrated in  FIG. 4 , a pressure reduction hole  110 , a concave portion  95   a , and a buffer chamber  30   b  are provided on the bottom face of the cartridge body  10  in addition to the ink supply hole  50  and the air intake hole  100  that have already been described above. The pressure reduction hole  110  is used for reducing the inner pressure of the cartridge body  10 . That is, air is sucked from the ink cartridge  1  through the pressure reduction hole  110  by using vacuuming means at the time of filling ink therein for inner pressure reduction. The concave portion  95   a  constitutes a part of the ink flow channel through which the ink-containing chambers communicate with the ink supply hole  50 . The buffer chamber  30   b  is provided below the ink end sensor  30 . 
   Immediately after production of an ink cartridge, the ink supply hole  50 , the air intake hole  100 , the pressure reduction hole  110 , the concave portion  95   a , and the buffer chamber  30   b  are sealed by sealing films  54 ,  90 ,  98 ,  95 , and  35 , respectively. The sealing film  90 , which seals the air intake hole  100 , is designed to be removed by a user before the ink cartridge is attached to an ink-jet recording apparatus for use thereof. The removal of the sealing film  90  makes the air intake hole  100  exposed to the outside so that the outside air can enter from the air intake hole  100  to flow through the air intake channel  150  and finally to reach the ink-containing chambers inside the ink cartridge  1 . 
   As illustrated in  FIGS. 6 and 7 , an ink supply needle  240 , which is provided on an ink-jet recording apparatus, is designed to pierce through the sealing film  54 , which is adhered to the edge of the ink supply hole  50 , when the ink cartridge  1  is attached to the ink-jet recording apparatus. 
   The inner structure of the ink supply hole  50  is made up of, as illustrated in  FIGS. 6 and 7 , a ring-shaped sealing member  51 , a spring stopper structure  52 , and a compression spring  53 . The ring-shaped sealing member  51  is pressed against the outer surface of the ink supply needle  240  when the ink cartridge  1  is attached to the ink-jet recording apparatus. The spring stopper structure  52  “press-contacts” with the sealing member  51  when the ink cartridge  1  is not attached to the ink-jet recording apparatus so as to block up the ink supply hole  50 . The compression spring  53  applies a pressing force to the spring stopper structure  52  toward the sealing member  51  for contact therebetween. 
   As understood from  FIGS. 6 and 7 , when the ink supply needle  240  is inserted into the ink supply hole  50 , the inner circumference portion of the sealing member  51  contacts the outer circumference portion of the ink supply needle  240  so as to seal a gap between the ink supply hole  50  and the ink supply needle  240  in liquid-tight condition. In addition thereto, the tip of the ink supply needle  240  contacts the spring stopper structure  52  and pushes the spring stopper structure  52  up so as to unseal the liquid-tight contact between the spring stopper structure  52  and the sealing member  51 . By this means, it becomes possible to supply ink from the ink supply hole  50  to the ink supply needle  240 . 
   Next, with reference to  FIGS. 8-12 , the inner configuration of the ink cartridge  1  according to the present embodiment of the invention is explained below. 
     FIG. 8  is a front view of the cartridge body  10  of the ink cartridge  1  according to the present embodiment of the invention.  FIG. 9  is a rear view of the cartridge body  10  of the ink cartridge  1  according to the present embodiment of the invention.  FIG. 10A  is a simplified diagram that corresponds to  FIG. 8 , whereas  FIG. 10B  is a simplified diagram that corresponds to  FIG. 9 .  FIG. 11  is a sectional view taken along the line A-A′ of  FIG. 8 .  FIG. 12  is a conceptual diagram that explains the route structure of the fluid channels formed in the cartridge body  10 . 
   In the ink cartridge  1  according to the present embodiment of the invention, an upper ink-containing chamber (i.e., upstream ink-containing chamber)  370 , a lower ink-containing chamber (i.e., downstream ink-containing chamber)  390 , and a buffer chamber  430  are formed at the front side of the cartridge body  10 . The upper ink-containing chamber  370  and the lower ink-containing chamber  390  constitute two main ink-containing chambers separated from each other. As illustrated in  FIG. 10B , the air intake channel  150  through which air taken in from the outside flows to reach the upper ink-containing chamber  370 , which is the most upstream ink-containing chamber, in accordance with the amount of ink consumed is provided at the rear side of the cartridge body  10 . The upper ink-containing chamber  370 , the lower ink-containing chamber  390 , and the buffer chamber  430  are partitioned from one another by the ribs  10   a . The ink flow channel  380  formed at the rear side of the cartridge body  10  communicates the upper ink-containing chamber  370  with the lower ink-containing chamber  390  via through holes that penetrate through the cartridge body  10  in its thickness direction. Similarly, the ink flow channel  420  formed at the rear side of the cartridge body  10  communicates the lower ink-containing chamber  390  with the buffer chamber  430  via through holes that penetrate through the cartridge body  10  in its thickness direction. With such a configuration, ink flows freely from the upstream chamber to the downstream chamber via the ink flow channels  380  and  420 . 
   First of all, with reference to  FIGS. 8-12 , the ink flow channel that leads from the upper ink-containing chamber  370 , which is a main ink-containing chamber, to the ink supply hole  50  is explained below. 
   The upper ink-containing chamber  370 , which is the most upstream ink-containing chamber of the cartridge body  10 , is formed at the front side of the cartridge body  10  as illustrated in  FIG. 8 . The upper ink-containing chamber  370  is an ink containing region/room that occupies approximately one half of the entire space of all ink-containing chambers. The upper ink-containing chamber  370  is formed approximately above the center of the cartridge body  10 . A through hole  371  via which the upper ink-containing chamber  370  is in communication with the ink flow channel  380  is formed in the upper ink-containing chamber  370 . The through hole  371  is formed at a position close to the lowest (i.e., bottom) part of the upper ink-containing chamber  370  that is partitioned by the ribs  10   a . With such a configuration, the surface level of remaining ink is still above the through hole  371  even when the amount of ink remaining in the upper ink-containing chamber  370  is small. 
   As illustrated in  FIG. 9 , the ink flow channel  380 , which is formed at the rear side of the cartridge body  10 , is designed to guide ink from the upstream upper ink-containing chamber  370  to the downstream lower ink-containing chamber  390 . 
   The lower ink-containing chamber  390  is an ink-containing room into which ink retained in the upper ink-containing chamber  370  flows. As illustrated in  FIG. 8 , the lower ink-containing chamber  390  is an ink-containing region that occupies approximately the other half of the entire space of all ink-containing chambers. The lower ink-containing chamber  390  is formed approximately below the center of the cartridge body  10 . A through hole  391  via which the ink flow channel  380  is in communication with the lower ink-containing chamber  390  is formed in the lower ink-containing chamber  390 . The through hole  391  is formed at a position close to the lowest part of the lower ink-containing chamber  390  that is partitioned by the ribs  10   a.    
   The lower ink-containing chamber  390  is in communication with an upstream ink end sensor intercommunicating flow channel  400  via another through hole that is not shown in the drawing. The upstream ink end sensor intercommunicating flow channel  400  has a three-dimensional intertwist flow channel. The intertwist structure of the upstream ink end sensor intercommunicating flow channel  400  is designed to trap any air bubbles or the like that has formed before reaching the ink end sensor. Thus, such air bubbles never flow to the downstream side of the upstream ink end sensor intercommunicating flow channel  400 . 
   The upstream ink end sensor intercommunicating flow channel  400  is in communication with the downstream ink end sensor intercommunicating flow channel  410  via still another through hole that is not shown in the drawing. Ink flows through the downstream ink end sensor intercommunicating flow channel  410  into the ink remaining amount detection sensor  31 . 
   The ink that has flown into the ink remaining amount detection sensor  31  passes through a cavity, which is a flow channel, of the ink remaining amount detection sensor  31  to be guided into the ink flow channel  420 , which is formed at the rear side of the cartridge body  10 . The ink flow channel  420  is configured to guide ink from the ink remaining amount detection sensor  31  in an inclined upward direction. A through hole  431  via which the ink flow channel  420  is in communication with the buffer chamber  430  is formed at the downstream end of the ink flow channel  420 . With such a structure, the ink that has flowed out of the ink remaining amount detection sensor  31  passes through the ink flow channel  420  to enter the buffer chamber  430 . 
   The buffer chamber  430  is a small room that is demarcated between the upper ink-containing chamber  370  and the lower ink-containing chamber  390  by the ribs  10   a . The buffer chamber  430  functions as an ink reservation space that is provided at a position immediately before entering the differential pressure regulation valve  40 . The buffer chamber  430  is formed at the rear side of the differential pressure regulation valve  40 . The ink flows from the buffer chamber  430  into the differential pressure regulation valve  40  via a through hole  432 . 
   The ink that has flown into the differential pressure regulation valve  40  is guided to the downstream side thereof by the differential pressure regulation valve  40  to flow into an exit flow channel  450  via a through hole  451 . The exit flow channel  450  leads to the ink supply hole  50 . The ink flows through the ink supply needle  240 , which is inserted into the ink supply hole  50 , to be supplied to the ink-jet recording apparatus. 
   Next, with reference to  FIGS. 8-12  again, the air intake channel  150  that leads from the air intake hole  100  to the upper ink-containing chamber  370  is explained below. 
   As ink retained in the ink cartridge  1  is consumed to reduce the inner pressure of the ink cartridge  1 , the outside air enters from the air intake hole  100  to flow into the upper ink-containing chamber  370  as much as the amount of ink consumed. 
   The small hole  102  formed inside the air intake hole  100  leads to one end of a meandering flow channel  310  that is formed at the rear side of the cartridge body  10 . The meandering flow channel  310 , which is a narrow and long fluid passage, is configured to have a long distance from the air intake hole  100  to the upper ink-containing chamber  370  so as to effectively suppress any undesirable evaporation of the moisture in ink. The other end of the meandering flow channel  310  leads to the air/liquid separation filter  70 . 
   A through hole  322  is formed in the dented surface of the air/liquid separation chamber  70   a , which constitutes a part of the air/liquid separation filter  70 . Via the through hole  322 , the air/liquid separation filter  70  is in communication with a space  320  that is formed at the front side of the cartridge body  10 . In the air/liquid separation filter  70 , the air/liquid separation film  71  is provided between the through hole  322  and the other end of the meandering flow channel  310 . The air/liquid separation filter  70  is a woven mesh textile material featuring high liquid-repellent/oil-repellent characteristics. 
   The space  320  is provided at the upper right area adjacent to the upper ink-containing chamber  370  when viewed from the front side of the cartridge body  10 . The space has another through hole  321  above the through hole  322 . Via the through hole  321 , the space  320  is in communication with an uppermost intercommunicating flow channel  330  that is formed at the rear side of the cartridge body  10 . 
   The uppermost intercommunicating flow channel  330  is configured to pass the uppermost portion of the ink cartridge  1  attached to the ink-jet recording apparatus, which is defined as “uppermost” along the direction in which gravitational force works. The uppermost intercommunicating flow channel  330  is made up of a flow channel portion  333 , a turn-around portion  335 , and a flow channel portion  337 . The flow channel portion  333  extends from the through hole  321  to the right along a long edge of the cartridge body  10  when viewed from the rear side thereof. After passing through the turn-around portion  335 , which is formed in the proximity of a short edge thereof, air flows through the flow channel portion  337  which is formed above the flow channel portion  333  to reach a through hole  341 , which is provided in the proximity of the through hole  321 . The through hole  341  leads to an ink trap chamber  340  that is formed at the front side of the cartridge body  10 . 
   While taking another look at the uppermost intercommunicating flow channel  330  from the rear side of the cartridge body  10 , a further explanation of the features thereof is given below. The flow channel portion  337  of the uppermost intercommunicating flow channel  330  that extends from the turn-around portion  335  to the through hole  341  has an area  336  at which the through hole  341  is formed and a concave portion  332  which has a relatively large depth in the thickness direction of the cartridge body  10  in comparison with the area  336 . A plurality of ribs  331  is formed so as to partition the concave portion  332 . In addition, the flow channel portion  333  thereof that extends from the through hole  321  to the turn-around portion  335  has a relatively small depth in comparison with the flow channel portion  337  thereof that extends from the turn-around portion  335  to the through hole  341 . 
   In this exemplary embodiment of the invention, as has already been described above, the uppermost intercommunicating flow channel  330  is configured to pass the uppermost portion of the ink cartridge  1 , viewed along the direction in which gravitational force works. For this reason, under normal use conditions, it is designed so that ink should never move against gravitational force to flow beyond the uppermost intercommunicating flow channel  330  toward the air intake hole  100 . In addition, the uppermost intercommunicating flow channel  330  is designed to have a diameter that is large enough to effectively prevent the backflow of ink due to a capillary phenomenon or the like. Moreover, since the concave portion  332  is provided in the flow channel portion  337 , it is designed to easily trap any ink that has flowed back to enter the concave portion  332 . 
   The ink trap chamber  340  is a space having the shape of a rectangular parallelepiped. The ink trap chamber  340  is formed at the upper right corner of the cartridge body  10  when viewed from the front side thereof. As illustrated in  FIG. 10A , the through hole  341  is formed in the proximity of the upper left distal corner of the ink trap chamber  340 . A notch portion  342 , which is formed by cutting out a part of the partition rib  10   a , is formed on the lower right proximal corner of the ink trap chamber  340 . The ink trap chamber  340  is in communication with an intercommunicating buffer chamber  350  through the notch portion  342 . The ink trap chamber  340  and the intercommunicating buffer chamber  350  are air chambers each of which is formed by enlarging the dimension (i.e., capacity) of a certain halfway point en route on the air intake channel  150 . The ink trap chamber  340  and the intercommunicating buffer chamber  350  are designed to trap, if any, ink that has flowed back from the upper ink-containing chamber  370  due to some reason so as to prevent such a back-flowed ink from going beyond the ink trap chamber  340  and the intercommunicating buffer chamber  350  toward the air intake hole  100 . 
   The intercommunicating buffer chamber  350  is a space formed below the ink trap chamber  340 . The pressure reduction hole  110 , which is provided for vacuuming at the time of filling of ink, is formed on the bottom surface  352  of the intercommunicating buffer chamber  350 . A through hole  351  is formed in the proximity of the bottom surface  352  in the thickness direction of the cartridge body  10 . The position at which the through hole  351  is formed lies in the lowermost portion of the ink cartridge  1  attached to the ink-jet recording apparatus, which is defined as “lowermost” along the direction in which gravitational force works. The intercommunicating buffer chamber  350  is in communication with an intercommunicating flow channel  360  via the through hole  351 . 
   The intercommunicating flow channel  360  extends toward the center of the cartridge body  10  in an upward direction when viewed from the rear side thereof. The intercommunicating flow channel  360  is in communication with the upper ink-containing chamber  370  via a through hole  372 , which is formed in the proximity of the bottom surface of the upper ink-containing chamber  370 . That is, an air passage leading from the air intake hole  100  to the intercommunicating flow channel  360  constitutes the air intake channel  150  according to the present embodiment of the invention. 
   As illustrated in  FIG. 8 , in the ink cartridge  1  according to the present embodiment of the invention, an empty chamber  501  in which no ink is filled is formed at the front side of the cartridge body  10  in addition to the aforementioned ink-containing chambers (upper ink-containing chamber  370 , lower ink-containing chamber  390 , and buffer chamber  430 ), air chambers (ink trap chamber  340  and intercommunicating buffer chamber  350 ), and ink flow channels (upstream ink end sensor intercommunicating flow channel  400  and downstream ink end sensor intercommunicating flow channel  410 ). 
   The empty chamber  501 , which is shown as a hatched area close to the left edge of the cartridge body  10  in the drawing, is demarcated between the upper ink-containing chamber  370  and the lower ink-containing chamber  390  at the front side thereof. An air hole  502  that penetrates the cartridge body  10  to the rear side thereof is provided at the upper left corner of the inner region of the empty chamber  501 . The air hole  502  leads to the outside thereof. When the ink cartridge  1  is subjected to vacuum packing, the empty chamber  501  becomes a deaeration chamber that contains/accumulates negative pressure for deaeration. 
   In the ink cartridge  1  having a configuration described above, even in a case where small air bubbles has formed in the cavity of the ink remaining amount detection sensor  31  during an ink-filling step of ink-cartridge production at a factory, such small air bubbles remaining in the cavity of the ink remaining amount detection sensor  31  dissolve into ink and thus disappear thanks to the action of deaeration negative pressure that expels any remaining air out of the ink cartridge  1  when the ink cartridge  1  is subjected to vacuum packing. Moreover, deaeration negative pressure applied at the time of vacuum packing is contained/accumulated in the no-ink-filled chamber (i.e., empty chamber)  501  in such a manner that the no-ink-filled chamber  501  of the cartridge body  10  functions as a pressure reduction space (i.e., deaeration chamber) that causes any air bubbles remaining in the cartridge body  10  to be dissolved to disappear effectively up to the time when a user opens the package of the ink cartridge  1 . Therefore, the invention provides the ink cartridge  1  that is capable of removing air bubbles that remain in the ink remaining amount detection sensor  31  with a greater certainty, thereby making it possible to prevent the ink remaining amount detection sensor  31  from performing erroneous detection attributable to the remaining air bubbles. 
   Furthermore, the ink cartridge  1  according to the present embodiment of the invention is provided with the ink trap chamber  340  and the intercommunicating buffer chamber  350  that are configured as air chambers each of which is formed by enlarging the dimension of a certain halfway point en route on the air intake channel  150  through which air that has been taken in from the outside flows to reach the upper ink-containing chamber  370  in accordance with the amount of ink consumed. Therefore, when any ink retained in the upper ink-containing chamber  370  flows back through the air intake channel  150  during use of the ink cartridge  1  due to thermal expansion, external vibration, or any other reason, it is possible to prevent the back-flowed ink from leaking out because the ink trap chamber  340  and the intercommunicating buffer chamber  350  that are provided as air chambers en route on the air intake channel  150  function as ink-trap spaces so as not to pass the back-flowed ink therethrough. 
   Still moreover, in a vacuum-packed state, the ink cartridge  1  according to the present embodiment of the invention is provided with the sealing film  90  that functions as a stopper to block the air intake channel  150  at an upstream position more closer to the air intake hole in comparison with the ink trap chamber  340  and the intercommunicating buffer chamber  350  that are configured as air chambers. Therefore, it is possible to ensure that ink does not leak out of the air intake hole in a vacuum-packed state. 
   It should be noted that the position at which the no-ink-filled chamber according to the invention is provided, the dimension thereof, and the number thereof are not limited to the specific example described in the above exemplary embodiment.  FIG. 13  is a front view of the cartridge body  10 A of an ink cartridge that is an example of a liquid container having no-ink-filled chambers according to a second embodiment of the invention. Compared with the cartridge body  10  according to the first embodiment of the invention, the cartridge body  10 A according to the second embodiment of the invention is provided with the upper ink-containing chamber  370  and lower ink-containing chamber  390  having a smaller dimension in comparison therewith so as to accommodate two additional no-ink-filled chambers  511  and  512 , which are demarcated between the ink-containing chambers (upper ink-containing chamber  370  and lower ink-containing chamber  390 ) and the air chambers (ink trap chamber  340  and intercommunicating buffer chamber  350 ) provided at the right edge portion of the cartridge body  10 A. 
   Except for the additional components of the no-ink-filled chambers  511  and  512 , the configuration of the cartridge body  10 A according to the second embodiment of the invention is the same as that of the cartridge body  10  according to the first embodiment of the invention. Therefore, in the following description, the same reference numerals are consistently used for the same components as those of the cartridge body  10  according to the first embodiment to omit any redundant explanation thereof. 
   These two no-ink-filled chambers  511  and  512  are vertically arranged adjacent to each other. The upper no-ink-filled chamber  511  is formed between the upper ink-containing chamber  370  and the ink trap chamber  340  by reducing the horizontal size of the upper ink-containing chamber  370 . On the other hand, the lower no-ink-filled chamber  512  is formed between the lower ink-containing chamber  390  and the intercommunicating buffer chamber  350  by reducing the horizontal size of the lower ink-containing chamber  390 . 
   These two no-ink-filled chambers  511  and  512  are in communication with each other via a notch portion  514  formed by cutting out a part of the partition rib  10   a  therebetween. Another notch portion  515  is formed by cutting out a part of the upper-edge partition rib  10   b  of the upper no-ink-filled chamber  511 . Via the notch portion  515 , the upper no-ink-filled chamber  511  is in communication with the outside (air) of the cartridge body  10 A. This further means that the lower no-ink-filled chamber  512  is also in communication with the outside of the cartridge body  10 A via the upper no-ink-filled chamber  511 . 
   Likewise the no-ink-filled chamber (i.e., empty chamber)  501  according to the first embodiment of the invention, these two no-ink-filled chambers  511  and  512  become deaeration chambers that contain/accumulate negative pressure for deaeration when the ink cartridge is subjected to vacuum packing. 
   With the addition of the no-ink-filled chambers  511  and  512 , according to the present embodiment of the invention, no-ink-filled chambers that become deaeration chambers when the ink cartridge is subjected to vacuum packing are formed at a plurality of positions in the cartridge body  10 A in a distributed layout. 
   In addition, these additional no-ink-filled chambers  511  and  512  are arranged adjacent to the upper ink-containing chamber  370 , the lower ink-containing chamber  390 , the ink trap chamber  340 , and the intercommunicating buffer chamber  350 . The total sum of the dimension of the no-ink-filled chambers  501 ,  511 , and  512  is configured to be larger than the sum of that of the ink trap chamber  340  and the intercommunicating buffer chamber  350  that constitute air chambers. 
   In the ink cartridge according to the second embodiment of the invention described above, the pressure-reducing action of deaeration negative pressure that is contained/accumulated in each of the no-ink-filled chambers  501 ,  511 , and  512  works at the plurality of positions in the cartridge  10 A. This ensures, advantageously, that the pressure-reducing action of deaeration negative pressure, which is effective for removing air bubbles, works in a wider area of the cartridge body  10  in a more uniform manner. In addition, such pressure-reducing action works multi-directionally (i.e., from a relatively large number of directions) on the position at which air bubbles have formed. For these reasons, the ink cartridge according to the second embodiment of the invention makes it possible to remove air bubbles with a greater efficiency than the ink cartridge according to the first embodiment of the invention. 
   In an ink cartridge having air chambers such as the ink trap chamber  340  and the intercommunicating buffer chamber  350 , generally speaking, a higher deaeration performance is required for removing air bubbles because the amount of air remaining in the cartridge body increases by the dimension of the ink trap chamber  340  and the intercommunicating buffer chamber  350 . In this respect, since the total sum of the dimension of the no-ink-filled chambers  501 ,  511 , and  512  is configured to be larger than the sum of that of the ink trap chamber  340  and the intercommunicating buffer chamber  350  that constitute air chambers, the ink cartridge according to the present embodiment of the invention makes it possible to easily maintain high deaeration performance. With an assured high deaeration performance, the invention makes it possible to remove air bubbles that remain in the ink remaining amount detection sensor  31  with a greater reliability. 
   In addition, in the ink cartridge according to the present embodiment of the invention, the no-ink-filled chambers  511  and  512  adjoin the upper/lower ink-containing chambers  370  and  390  with a partition wall interposed therebetween in such a manner that each of them has a wide adjoining area. Similarly, the no-ink-filled chambers  511  and  512  further adjoin the ink trap chamber  340  and the intercommunicating buffer chamber  350  with a partition wall interposed therebetween in such a manner that each of them has a wide adjoining area. Having such a structure, the ink cartridge according to the present embodiment of the invention makes it possible to improve the deaeration efficiency inside the cartridge body  10 A so as to remove air bubbles that remain in the ink remaining amount detection sensor  31  with a greater reliability. Thus, the ink cartridge according to the present embodiment of the invention makes it possible to prevent the ink remaining amount detection sensor  31  from performing erroneous detection that could be caused by the remaining air bubbles. 
     FIG. 14  is a front view of the cartridge body  10 B of an ink cartridge that is an example of a liquid container having no-ink-filled chambers according to a third embodiment of the invention.  FIG. 15  is a rear view of the cartridge body  10 B of the ink cartridge that is an example of a liquid container having no-ink-filled chambers according to the third embodiment of the invention. In comparison with the cartridge body  10 A according to the second embodiment of the invention, the cartridge body  10 B according to the third embodiment of the invention has a further additional no-ink-filled chamber  521 , which is demarcated between the buffer chamber  430  and the lower ink-containing chamber  390  at a space vacated by reducing the size of the lower ink-containing chamber  390 . 
   Except for the additional component of the no-ink-filled chamber  521 , the configuration of the cartridge body  10 B according to the third embodiment of the invention is the same as that of the cartridge body  10 A according to the second embodiment of the invention. Therefore, in the following description, the same reference numerals are consistently used for the same components as those of the cartridge body  10 A according to the second embodiment to omit any redundant explanation thereof. 
   The no-ink-filled chamber  521  adjoins the lower ink-containing chamber  390 , which are formed in the proximity of the cavity of the ink remaining amount detection sensor  31 , and the upstream ink end sensor intercommunicating flow channel  400  and downstream ink end sensor intercommunicating flow channel  410 . An air hole  522 , which penetrates the cartridge body  10  to the rear side thereof, is formed in the neighborhood of the approximately central position of the cartridge body  10 B. The no-ink-filled chamber  521  is in communication with the outside of the cartridge body  10 B via the air hole  522 . Similar to other no-ink-filled chambers, the empty chamber  521  has no ink filled therein. When the ink cartridge is subjected to vacuum packing, the no-ink-filled chamber  521  becomes a deaeration chamber that contains/accumulates negative pressure for deaeration. 
   In the ink cartridge according to the present embodiment of the invention, with the addition of the no-ink-filled chamber  521 , the total sum of dimension of all of the no-ink-filled chambers is designed to be larger than that of all of the ink-containing chambers (that is, the aggregate dimension of the upper ink-containing chamber  370 , lower ink-containing chamber  390 , and buffer chamber  430 ). 
   When the total sum of dimension of the no-ink-filled chambers is larger than that of the ink-containing chambers, a comparatively large amount of negative pressure for deaeration is contained/accumulated in the no-ink-filled chambers  501 ,  511 ,  512 , and  521 . This makes it possible to maintain an ink cartridge contained in a vacuum-packed package in a good pressure-reduced environment until a user opens the package thereof, thereby making it possible to prolong the efficacy of reduced pressure in removing air bubbles in the vacuum-packed ink cartridge for a long time. Thus, with the configuration of the ink cartridge according to the present embodiment of the invention, it is possible to further improve the shelf life of a vacuum-packed ink cartridge. In particular, since the no-ink-filled chamber  521  is formed adjacent to the ink-containing region in the proximity of the cavity of the ink remaining amount detection sensor  31 , it is possible to remove air bubbles that remain in the cavity of the ink remaining amount detection sensor  31  in a greater reliability. Moreover, with the addition of the no-ink-filled chamber  521 , the ink cartridge is configured such that a greater number of the no-ink-filled chambers are formed inside the cartridge body thereof in a distributed layout. With such a structure, it is possible to further enhance the advantageous effects of the distributed arrangement of empty chambers (that is, more uniform pressure-reducing action that works on the entire region of the ink cartridge). 
   It should be noted that the application/use of a liquid container according to the present invention is not limited to an ink cartridge that is described in the above exemplary embodiments of the invention. It should be further noted that the application/use of a liquid consumption apparatus that is provided with a container attachment unit to which a liquid container according to the present invention is detachably attached is not limited to an ink-jet recording apparatus that is described in the above exemplary embodiments of the invention. In addition to an ink-jet recording apparatus described in the exemplary embodiments above, a liquid consumption apparatus to which the invention is applicable encompasses a wide variety of other types of apparatuses such as one that is provided with a container attachment unit to which a liquid container is detachably attachable so as to supply liquid retained therein to the apparatus. Examples of a liquid consumption apparatus according to the invention include, without any limitation thereto: an apparatus that is provided with a color material ejection head that is used in the production of color filters for a liquid crystal display device or the like; an apparatus that is provided with an electrode material (i.e., conductive paste) ejection head that is used for electrode formation for an organic EL display device, a surface/plane emission display device (FED), and the like; an apparatus that is provided with a living organic material ejection head used for production of biochips; and an apparatus that is provided with a sample ejection head functioning as a high precision pipette.