Patent Publication Number: US-8967763-B2

Title: Liquid containing chamber and liquid ejecting apparatus

Description:
This application claims priority to Japanese Patent Application No. 2010-060464, filed Mar. 17, 2010, the entirety of which is incorporated by reference herein. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to liquid containing chambers that supply liquid to liquid ejecting apparatuses, and relates to liquid ejecting apparatuses. 
     2. Related Art 
     In liquid ejecting apparatuses such as ink jet recording apparatuses, ink jet textile printing apparatuses and microdispensers, a liquid such as ink is supplied from a liquid containing chamber that contains liquid, and then ejected. As an example of such a liquid which is contained in a containing chamber, pigment ink may be used. The pigment ink is manufactured by dispersing pigment particles in a dispersion medium. Therefore, pigment particles may settle over time, leading to variation in the concentration of the pigment ink. 
     JP-A-2006-188008 discloses a technique of reducing the variation in the concentration of the pigment ink, in which air is enclosed in a reservoir (also referred to as “liquid container”) that contains the pigment ink, and then an ink cartridge is reciprocated so as to permit the movement of ink in the reservoir, thereby causing stirring of ink. 
     Further, JP-A-2007-230189 and JP-A-2006-44153 disclose a technique of reducing the variation in the concentration of the pigment ink, in which a stirring member and a support member for rotatably supporting the stirring member are provided, wherein ink is stirred by the stirring member. 
     However, when ink is stirred with air which is enclosed in the reservoir, the extent to which ink is moved by air (range of movement) is limited, therefore the pigment ink with the higher concentration, which is located vertically below and at the bottom of the reservoir, may not become stirred. Particularly, when the reservoir is elongated in the vertical direction, it is difficult to stir the pigment ink located at the bottom of the reservoir. On the other hand, when ink is stirred by means of a stirring member, the larger the reservoir is, the larger the stirring member needs to be in order to obtain a stirring effect. As a result, the cost of the ink cartridge may be increased. These problems are present not only in ink cartridges, but also in liquid containing chambers in general that contain a dispersion substance with variation in concentration. 
     Therefore, the invention seeks to solve at least part of the above problems, reducing the variation in the concentration of the liquid in the liquid container by stirring liquid in a liquid container with a stirring member having a more compact size. 
     SUMMARY 
     An advantage of some aspects of the invention is that at least some of the above problems are solved thereby and the aspect of the invention can be implemented as the following embodiments or examples. 
     Example 1 
     A liquid containing chamber that supplies liquid to a liquid ejecting apparatus including: a liquid supply unit that supplies the liquid to the liquid ejecting apparatus; a first liquid container that is capable of containing the liquid, the first liquid container having a maximum length in the vertical direction which is longer than a maximum length in a direction perpendicular to the vertical direction in a mounted position in which the liquid containing chamber is mounted in the liquid ejecting apparatus that is placed on a flat plane perpendicular to the vertical direction such that the liquid supply unit is located at a vertically lower position; a first projection provided in the first liquid container; and a first stirring member supported by the first projection so as to be rotatable within a predetermined range of angles and having a plate shape extending from the supported position toward a bottom of the first liquid container in the mounted position, wherein the first stirring member is rotatable around the first projection by the acceleration of the liquid containing chamber including a predetermined direction component, and, in an initial state which is before the liquid is supplied by the liquid containing chamber to the liquid ejecting apparatus, when the first liquid container in the mounted position is divided into an upper container which is located vertically above the first projection and a lower container which is located vertically below the upper container, the lower container contains the liquid and the upper container contains the liquid and an amount of air that enables stirring of the liquid in the upper container including the liquid stirred by the first stirring member by allowing the movement of the liquid in the upper container. 
     According to the liquid containing chamber described in Example 1, the upper container contains an air and stirs the liquid in the upper container by means of the air that permits the movement of the liquid in the upper container including the liquid stirred by the first stirring member. That is, in the mounted position of the liquid containing chamber, it is possible to stir the entire liquid in the vertically long shaped first liquid container by the first stirring member without having a height of the first stirring member corresponding to the height of the first liquid container. This makes it possible to reduce the variation in the concentration of the liquid in the first liquid container while allowing the first stirring member to be more compact. 
     Example 2 
     The liquid containing chamber according to Example 1, wherein an end of the first stirring member opposing the bottom has a shape which generally corresponds to the entire area of at least the bottommost part of the bottom which is located at the bottommost position of the bottom, and in the mounted position, the first stirring member is arranged in the first liquid container such that the end is positioned at least in proximity to the bottommost part. 
     According to the liquid containing chamber described in Example 2, the liquid which is most likely to have highest concentration in the first liquid container, which is located in proximity to the bottommost part of the bottom, can be stirred, therefore the variation in the concentration of the liquid in the first liquid container can be reduced. The above description “a shape which generally corresponds to the entire area of the bottommost part of the bottom” means a shape such that the entire liquid which is located in proximity to the bottommost part of the bottom can be flown by the first stirring member. Specifically, when the liquid containing chamber is directly projected on the side perpendicular to the vertical direction in the mounted position, the length of the end which opposes the bottommost part is 70% or more of the length of the bottom. Further, the above description “in proximity to the bottommost part” means that, in the vertical direction in the mounted position, the length from the bottommost part to the end that opposes the bottommost part is 30% or less of the length from a point where the first stirring member is supported by the first projection to the end that opposes the bottommost part. 
     Example 3 
     The liquid containing chamber according to Example 2, wherein the end has a shape which generally corresponds to the entire area of the bottom, and in the mounted position, the first stirring member is arranged in the first liquid container such that the end is positioned at least in proximity to the bottom. 
     According to the liquid containing chamber described in Example 3, the liquid which is likely to have the higher concentration in proximity to the bottom can be stirred, therefore the variation in the concentration of the liquid in the first liquid container can be reduced. The above description “a shape which generally corresponds to the entire area of the bottom” means a shape such that the entire liquid which is located in proximity to the bottom can be flown by the first stirring member. Specifically, when the liquid containing chamber is directly projected on the side perpendicular to the vertical direction in the mounted position, the length of the end is 70% or more of a length of the bottom. Further, the above description “in proximity to the bottom” means that, in the vertical direction in the mounted position, the length from the bottom to the end that opposes the bottom is 30% or less of the length from a point where the first stirring member is supported by the first projection to the end that opposes the bottom. 
     Example 4 
     The liquid containing chamber according to any one of Examples 1 to 3, wherein in the initial state, the upper container contains air accounting for a volume of 30% or more and 50% or less of the volume of the upper container. According to the liquid containing chamber described in Example 4, it is possible to efficiently stir the entire liquid including the liquid which is located at the lowest position in the upper container by allowing the movement of the liquid in the upper container. Accordingly, the entire liquid in the upper container including the liquid stirred by the first stirring member can be efficiently stirred, therefore the variation in the concentration of the liquid in the first liquid container can be further reduced. 
     Example 5 
     The liquid containing chamber according to any one of Examples 1 to 4, further including: a second liquid container which is located downstream of the first liquid container in a flow direction of the liquid being supplied to the liquid ejecting apparatus, the second liquid container having a horizontally long shape in the mounted position; a second projection provided in the second liquid container; and a second stirring member supported by the second projection so as to be rotatable within a predetermined range of angles and having a plate shape extending from the supported position toward a second bottom which is the bottom of the second liquid container in the mounted position, wherein the first liquid container has an air communication hole for communicating with air, the second stirring member is rotatable around the second projection by the acceleration of the liquid containing chamber including a predetermined direction component, in the initial state, the second liquid container contains the liquid, and the second stirring member stirs the liquid contained in the second liquid container by rotation of the second stirring member. 
     According to the liquid containing chamber described in Example 5, even if the second liquid container is disposed downstream of the first liquid container, it is possible to reduce the variation in the concentration of the liquid in the second liquid container by the second stirring member stirring the liquid. Therefore, the liquid with the variation in concentration being reduced can be supplied to the liquid ejecting apparatus. Further, when the second liquid container is provided in addition to the first liquid container, a backflow of the liquid flowing from the first liquid container toward the air communication hole may be reduced, compared with when the second liquid container is not provided. 
     Example 6 
     The liquid containing chamber according to Example 5, further including: a second side which is perpendicular to the second bottom and opposes the plate surface of the second stirring member, wherein the second stirring member has a shape which covers the entire area of the second side when the second stirring member is directly projected on the second side, the second end of the second stirring member which opposes the second bottom has a shape which generally corresponds to the entire area of the second bottommost part which is located at the bottommost position of the second bottom, and in the mounted position, the second stirring member is arranged in the second liquid container such that the second end is positioned at least in proximity to the second bottommost part. 
     According to the liquid containing chamber described in Example 6, the liquid which is likely to have the highest concentration in proximity to the bottommost part of the second liquid container can be stirred. Further, the second stirring member has a shape so as to cover the entire area of the second side, thereby allowing the liquid moved upward by the second stirring member to be flown across the entire area of the second liquid container. Therefore, the variation in the concentration of the liquid in the second liquid container can be further reduced. 
     The above description “a shape which covers the entire area of the second side” means that the plate surface of the second stirring member has a surface area of 50% or more of the surface area of the second side. Further, the above description “a shape which generally corresponds to the entire area of the second bottommost part” means a shape such that the entire liquid in proximity to the second bottommost part can be flown by the first stirring member. Specifically, when the liquid containing chamber is directly projected on the side perpendicular to the vertical direction in the mounted position, the length of the second end is 70% or more of the length of the second bottommost part. Further, the above description “in proximity to the second bottommost part” means that, in the vertical direction in the mounted position, a length from the second bottommost part to the end that opposes the second bottommost part is 30% or less of the length from a point where the second stirring member is supported by the second projection to the end that opposes the second bottommost part. 
     Example 7 
     The liquid containing chamber according to Example 6, wherein the second end has a shape which generally corresponds to the entire area of the second bottom, and in the mounted position, the second stirring member is arranged in the second liquid container such that the second end is positioned in proximity to the second bottom. 
     According to the liquid containing chamber described in Example 7, the liquid which is likely to have the higher concentration in proximity to the bottom of the second liquid container can be stirred. This allows the liquid moved upward by the second stirring member in proximity to the second bottom can be flown across the entire area of the second liquid container. Therefore, the variation in the concentration of the liquid in the second liquid container can be further reduced. 
     The above description “a shape which generally corresponds to the entire area of the second bottom” means a shape such that the entire liquid in the second liquid container can be flown across the entire area in the second liquid container. Specifically, when the liquid containing chamber is directly projected on the side perpendicular to the vertical direction in the mounted position, the length of the second end is 70% or more of the length of the second bottom. Further, the above description “in proximity to the second bottom” means that, in the vertical direction in the mounted position, the length from the second bottom to the second end that opposes the second bottom is 30% or less of the length from a point where the second stirring member is supported by the second projection to the second end that opposes the second bottom. 
     Example 8 
     A liquid ejecting apparatus including the liquid containing chamber mounted therein according to any one of Examples 1 to 7. 
     According to the liquid ejecting apparatus described in Example 8, the liquid can be ejected with the variation in concentration being reduced. 
     The present invention can be implemented in various embodiments, such as the above mentioned liquid containing chambers and liquid ejecting apparatuses having such a liquid containing chamber as well as a method of stirring liquid in the liquid containing chamber. 
    
    
     
       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 a view of a printer having an ink cartridge mounted thereon. 
         FIG. 2  is an exploded perspective view of the ink cartridge. 
         FIG. 3  is a schematic view of a path extending from an air open hole to a liquid supply unit. 
         FIG. 4  is a front elevation view of a case body. 
         FIG. 5  is a rear elevation view of the case body. 
         FIG. 6  is a view explaining first and second liquid containers. 
         FIGS. 7A and 7B  are views explaining a configuration of the first liquid container. 
         FIG. 8  is a view explaining a relationship between a first stirring member and a bottom. 
         FIGS. 9A ,  9 B,  9 C and  9 D are views explaining a stirring state of the first liquid container. 
         FIGS. 10A and 10B  are views explaining a configuration of the second liquid container. 
         FIGS. 11A and 11B  are views explaining a stirring state of the second liquid container. 
         FIGS. 12A and 12B  are views explaining first and second variations of embodiments. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The embodiments of the invention will be described below in the order of: 
     A. First embodiment; and 
     B. Variations of embodiments. 
     A. First Embodiment 
     A-1. Schematic Configuration of Ink Cartridge 
       FIG. 1  is a view of an ink jet printer  1  having ink cartridges  10  mounted thereon according to a first embodiment of the present invention. The XYZ axes are used to identify the directions in  FIG. 1  and in the subsequent figures, as necessary. An ink jet printer  1  (also referred to simply as “printer  1 ”) as a liquid ejecting apparatus includes a carriage  12  that reciprocates (accelerates) in a main scan direction (a paper width direction). The carriage  12  is moved via a timing belt  15  by driving a stepping motor  16 . A recording head  14  is mounted on the bottom of the carriage  12  such that ink is ejected through nozzles on the recording head  14  for printing on a printing sheet PP. The carriage  12  is also provided with a cartridge housing in which the ink cartridges  10  as a plurality of liquid containing chambers can be loaded. Each ink cartridge  10  has a liquid detector (not shown) for detecting the remaining amount of ink. The liquid detector is electrically connected to the printer  1 , such that detection signals can be transmitted to and received from the printer  1 . 
       FIG. 2  is an exploded perspective view of the ink cartridge  10 . The ink cartridge  10  includes a case body  20  which is open to one side (in the positive Y axis direction), a first film  32  which covers the open side of the case body  20 , a second film  33  which covers the other side of the case body  20  (in the negative Y axis direction), and a cover member (not shown) which covers the first film  32 . The ink cartridge  10  has a substantially rectangular appearance when each of the members are assembled together. The case body  20  and the cover member are each integrally formed of a synthetic resin such as polypropylene. 
     A plurality of ribs  202  in a variety shapes is formed in the case body  20 . The first film  32  is closely adhered to the edges of the ribs  202  of the case body  20  so that no gap is formed therebetween. These ribs  202  and the first film  32  cooperatively form a plurality of small chambers (liquid containers) for containing the pigment ink. Hereinafter, the side of the case body  20  on which a plurality of small chambers are formed is referred to as the front side, while the opposite side to the front side is referred to as the rear side. The liquid container for containing the pigment ink will be described later in detail. 
     The case body  20  further includes a liquid supply unit  34  that supplies the pigment ink from the liquid container to the printer  1 . A valve mechanism (not shown) is arranged inside the liquid supply unit  34 . When the ink cartridges  10  are mounted in the carriage  12  ( FIG. 1 ), a liquid supply needle (not shown) disposed on the carriage  12  works to open the valve mechanism which is arranged inside the liquid supply unit  34 . This allows the pigment ink to flow into the liquid supply needle, and to then be supplied to the printer  1 . An air open hole  100  (see  FIG. 4 ) for introducing air into the ink cartridge  10  is further provided on the side of the case body  20  on which the liquid supply unit  34  is formed (in the negative Z axis direction). Further, various flow channels, which will be described below in detail, are formed on the rear side of the case body  20 . In addition, a differential valve  37   a  (see  FIG. 5 ) that maintains a specific area in the case body  20  at a negative pressure is also disposed on the rear side of the case body  20 . 
     Next, before explaining a configuration of the ink cartridge  10  in further detail, a path extending from the air open hole  100  to the liquid supply unit  34  is described below with reference to  FIG. 3  to facilitate understanding.  FIG. 3  is a schematic view of the path extending from the air open hole  100  of the ink cartridge  10  to the liquid supply unit  34 . 
     The path extending from the air open hole  100  to the liquid supply unit  34  is broadly divided into a liquid container where the pigment ink is contained, an air flow channel that is located upstream of the liquid container, and an intermediate flow channel that is located downstream of the liquid container. The term “upstream” and “downstream” as used herein are defined based on the flow direction of the pigment ink being supplied to the printer  1 . 
     The liquid container is composed of a first liquid container  40 , a first container connection path  219 , a second container connection path  222 , a third container connection path  223  and a second liquid container  50 , arranged in sequence in the downstream direction. The first and second liquid containers  40  and  50  communicate via the first, second and third container connection paths  219 ,  222  and  223 . 
     The air flow channel is composed of a meandering path  204 , an air/liquid separation chamber  110 , a first connection path  207 , a second connection path  210 , an air container  36  and a third connection path  216 , arranged in sequence in the downstream direction. The meandering path  204  is formed in an elongated meandering shape so as to increase the distance from the air open hole  100  to the first liquid container  40 . This can help reduce water evaporation from the pigment ink which is contained in the liquid container. An air/liquid separation film, which is not shown, is arranged in the air/liquid separation chamber  110 . The air/liquid separation film is made of a material that is permeable to gas but impermeable to liquid. Further, an air container  36  for containing air is disposed downstream of the air/liquid separation chamber  110 . The air/liquid separation chamber  110  and the air container  36  communicate via the first and second connection paths  207  and  210 , while the air container  36  and the first liquid container  40  communicate via the third connection path  216 . 
     The intermediate flow channel is composed of a labyrinth flow channel  230 , a liquid flow section  231 , a first liquid flow channel  236 , a sensor unit  120 , a second liquid flow channel  242 , a buffer chamber  70 , a differential pressure valve containing chamber  37  that contains the differential pressure valve, a third liquid flow channel  250  and a fourth liquid flow channel  256 , arranged in sequence in the downstream direction. The labyrinth flow channel  230  is in a three-dimensional labyrinth form. The liquid flow section  231  is connected downstream of the labyrinth flow channel  230 . The liquid flow section  231  and the sensor unit  120  communicate via the first liquid flow channel  236 . A sensor  121  is arranged in the sensor unit  120 . As the pigment ink is used in the printer  1  and air is introduced into the sensor unit  120 , the sensor  121  outputs a signal indicative of a shortage of ink to the printer  1 . 
     The sensor unit  120  and the buffer chamber  70  communicate via the second liquid flow channel  242 . The differential pressure valve which is contained in the differential pressure valve containing chamber  37  adjusts a pressure of the pigment ink downstream of the differential pressure valve containing chamber  37  to be lower than a pressure of the pigment ink upstream of the differential pressure valve containing chamber  37 . Moreover, the differential pressure valve maintains the pigment ink downstream of the differential pressure valve containing chamber  37  at a negative pressure. The differential pressure valve containing chamber  37  and the liquid supply unit  34  communicate via the third and fourth liquid flow channels  250  and  256 . In an initial state, in which the ink cartridge  10  is in the same state as when it was made as a finished product (i.e., before the pigment ink is supplied to the printer  1 ), the liquid surface of the pigment ink comes to the position in the first liquid container  40  which is schematically shown by the dotted line ML. 
       FIG. 4  is a front elevation view of the case body  20 . In  FIG. 4 , the ink cartridge  10  is in a state of being mounted in the carriage  12  ( FIG. 1 ) of the printer  1  (hereinafter, also referred to as “mounted position”), where the Z axis is the vertical direction and the negative Z axis is the vertically down direction. Moreover, in the mounted position, the ink cartridge  10  is reciprocated (accelerated) along the Y axis by reciprocating (accelerating) the carriage  12 . It should be noted that the mounted position refers to the position in which the ink cartridge  10  is mounted in the printer  1  that is placed on the flat plane perpendicular to the vertical direction. 
     In the air flow channel, the first connection path  207  and the air container  36  is formed on the front side of the case body  20 . In  FIG. 4 , the air container  36  is shown cross hatched for purpose of illustration. 
     In the liquid container, the first liquid container  40 , the first container connection path  219 , the third container connection path  223  and the second liquid container  50  are formed on the front side of the case body  20 . A first stirring member  80  for stirring the pigment ink is disposed in the first liquid container  40 . Further, a first support member  310  that supports the first stirring member  80  is also disposed in the first liquid container  40  such that the first stirring member  80  is rotatable within a predetermined range of angles. Similarly, a second stirring member  90  for stirring the pigment ink is disposed in the second liquid container  50 . Further, a second support member  320  that supports the second stirring member  90  is also disposed in the second liquid container  50  such that the second stirring member  90  is rotatable within a predetermined range of angles. The first and second stirring members  80  and  90  are both formed in a plate shape having a given thickness and made of a member having a specific gravity greater than that of the pigment ink contained in the ink cartridge  10 . The first and second support members  310  and  320  are part of the case body  20  and integrally formed with the case body  20 . In this embodiment, the first and second stirring members  80  and  90  are made of stainless steel. The details of the first and the second liquid containers  40 ,  50 , the first and second stirring members  80 ,  90  and the first and second support members  310 ,  320  will be further described later. 
     In the intermediate flow channel, part of the labyrinth flow channel  230 , the liquid flow section  231 , the buffer chamber  70  and the third liquid flow channel  250  are formed on the front side of the case body  20 . In  FIG. 4 , the buffer chamber  70  is shown single hatched for the purpose of illustration. Further, the sensor unit  120  is formed inside the lower left portion of the case body  20  in  FIG. 4 . 
       FIG. 5  is a rear elevation view of the case body  20 . In the air flow channel, the meandering path  204 , the air/liquid separation chamber  110 , the second connection path  210  and the third connection path  216  are formed on the rear side of the case body  20 . In the liquid container, the second container connection path  222  is formed on the rear side of the case body  20 . In the intermediate flow channel, part of the labyrinth flow channel  230 , the first liquid flow channel  236 , the second liquid flow channel  242 , the differential pressure valve containing chamber  37  and the fourth liquid flow channel  256  are formed on the rear side of the case body  20 . The meandering path  204 , the second connection path  210 , the second container connection path  222 , the first liquid flow channel  236 , the second liquid flow channel  242  and the fourth liquid flow channel  256  are groove-shaped flow channels. The differential pressure valve containing chamber  37  is a space having a substantially cylindrical shape, in which the differential pressure valve  37   a  is housed. 
     As shown in  FIGS. 4 and 5 , the communication holes  203 ,  206 ,  208 ,  212 ,  214 ,  218 ,  220 ,  224 ,  232 ,  238 ,  240 ,  244 ,  246 ,  248 ,  252  and  258  are formed in the case body  20  so as to allow the respective elements of the air flow channel, the liquid container and the intermediate flow channel to communicate with each other. The air open hole  100  and the meandering path  204  communicate via the communication hole  203  ( FIG. 5 ). The air/liquid separation chamber  110  and the first connection path  207  ( FIG. 4 ) communicate via the communication hole  206  ( FIG. 5 ). The first connection path  207  and the second connection path  210  ( FIG. 5 ) communicate via the communication hole  208 . The second connection path  210  and the air container  36  ( FIG. 4 ) communicate via the communication hole  212 . The air container  36  and the third connection path  216  ( FIG. 5 ) communicate via the communication hole  214 . The third connection path  216  and the first liquid container  40  ( FIG. 4 ) communicate via the communication hole  218 . The first liquid container  40  and the first container connection path  219  ( FIG. 4 ) communicate via a gap S 1  between the ribs, and the first container connection path  219  and the second container connection path  222  ( FIG. 5 ) communicate via the communication hole  220 . The second container connection path  222  and the third container connection path  223  ( FIG. 4 ) communicate via the communication hole  224 . 
     The third container connection path  223  communicates with the second liquid container  50  via a gap S 2  between the ribs. The second liquid container  50  communicates with the upstream end of the labyrinth flow channel  230 , while the downstream end of the labyrinth flow channel  230  communicates with the liquid flow section  231 . 
     The liquid flow section  231  and the first liquid flow channel  236  ( FIG. 5 ) communicate via the communication hole  232 . The first liquid flow channel  236  and the sensor unit  120  ( FIG. 4 ) communicate via the communication hole  238 . The sensor unit  120  and the second liquid flow channel  242  ( FIG. 5 ) communicate via the communication hole  240 . The second liquid flow channel  242  and the buffer chamber  70  ( FIG. 4 ) communicate via the communication hole  244 . The buffer chamber  70  and the differential pressure valve containing chamber  37  ( FIG. 5 ) communicate via the communication hole  246 . The differential pressure valve containing chamber  37  and the third liquid flow channel  250  ( FIG. 4 ) communicate via the communication hole  248 . The third liquid flow channel  250  and the fourth liquid flow channel  256  ( FIG. 5 ) communicate via the communication hole  252 . The fourth liquid flow channel  256  and a flow channel formed in the liquid supply unit  34  in the vertical direction communicate via the communication hole  258 . That is, the pigment ink passes through the communication hole  258  and flows into the liquid supply unit  34  and then into the printer  1 . 
     As the pigment ink is supplied from the liquid supply unit  34  to the printer  1 , air is introduced through the air open hole  100  into the ink cartridge  10 . 
     A-2. Detailed Configuration of Liquid Container of Ink Cartridge 
       FIG. 6  is a view of the first and second liquid containers  40  and  50 .  FIG. 6  is a front elevation view of the case body  20  with part of the configuration that does not need to be explained not being shown. The first liquid container  40  is single hatched and the second liquid container  50  is cross hatched for clarity of illustration. In the mounted position, the first liquid container  40  is vertically long, while the second liquid container  50  is horizontally long. The term “vertically long” means that the first liquid container  40  is oriented in the mounted position so as to have the outer dimensions in which the maximum length in the vertical direction (Z axis direction) is longer than the maximum length in the direction perpendicular to the vertical direction and parallel to a first side, which is described later (X axis direction). Further, the term “horizontally long” means that the second liquid container  50  is oriented in the mounted position so as to have outer dimensions in which the maximum length in the Z axis direction is shorter than the maximum length in the X axis direction. In the initial state of the ink cartridge  10 , the pigment ink is contained in the ink cartridge  10  such that the liquid surface of the pigment ink comes to the position in the first liquid container  40  as indicated by the dotted line ML. That is, the first liquid container  40  contains both the pigment ink and air in the initial state, while the second liquid container  50  is filled with the pigment ink in the initial state. 
       FIG. 7  is a view of a configuration of the first liquid container  40 .  FIG. 7A  is a sectional view taken along the line VIIA-VIIA of  FIG. 6  with part of the configuration that does not need to be explained not being shown.  FIG. 7B  is a view of the first liquid container  40  seen from the positive Y axis with part of the configuration that does not need to be explained not being shown. That is,  FIG. 7B  corresponds to a view in which the first stirring member  80  is directly projected on the first side, which is described later. In  FIG. 7B , the liquid surface of the pigment ink is indicated by the dotted line ML. The boundary between an upper container  40   b  and a lower container  40   a  of the first liquid container  40 , both of which are described later, is indicated by the dashed dotted line TL. 
     As shown in  FIG. 7A , the first liquid container  40  is an area defined by a bottom  402  which is located at a vertically lower position, a top  408  which is located vertically above the bottom  402  so as to oppose the bottom  402  and a first side  403  perpendicular to the bottom  402  and extends upwardly from the bottom  402  in the mounted position. The first side  403  is positioned so as to oppose the plate surface of the first stirring member  80 . A side  401  which opposes the first side  403  is entirely open. As shown in  FIG. 7B , the first liquid container  40  is further defined by a first member side  404  and a second member side  406  which both extend upwardly from the bottom  402 . 
     As shown in  FIG. 7B , the bottom  402  has a bottommost part of the bottom  402   a  and an upper part of the bottom  402   b . The bottommost part of the bottom  402   a  is a plane located at the bottommost position of the bottom  402  and substantially parallel to the direction perpendicular to the vertical direction and parallel to the first side  403  (also referred to as “horizontal direction” or “X axis direction”). The upper part of the bottom  402   b  is a plane located above the bottommost part of the bottom  402   a  and substantially parallel to the horizontal direction. The first stirring member  80  has a shape which allows the entire pigment ink in proximity to the bottom  402  to be stirred. Specifically, an end  802  of the first stirring member  80  has a first end  802   a  which opposes the bottommost part of the bottom  402   a  and a second end  802   b  which opposes the upper part of the bottom  402   b . The end  802  has a shape which generally corresponds to the entire area of the bottom  402 . The shape of the first stirring member  80  will be described later in detail. Moreover, the first stirring member  80  is arranged in the first liquid container  40  such that the end  802  is in proximity to the bottom  402 . 
     As shown in  FIG. 7A , two first support members  310  (one of them is shown in the figure) which extend from the first side  403  toward the open side are formed in the first liquid container  40 . The first support member  310  is composed of a base  312  in a substantially cylindrical shape, a cylindrical projection  314  connected to the base  312  and a first stopper  316  in a circular plate shape which is connected to the projection  314 . Two notches are formed on the outer periphery of the first stirring member  80 . When those notches are interdigitated with the projection  314  having a certain gap therebetween, the first stirring member  80  is support by the first support member  310  to be rotatable within a predetermined range of angles. 
     The first stirring member  80  is a plate member having a given thickness. The first stirring member  80  extends from the position supported by the projection  314  toward the bottom  402  by a given distance. When the ink cartridge  10  is loaded in the carriage  12  ( FIG. 1 ), the ink cartridge  10  moves with acceleration in the main scan direction that is perpendicular to the first side  403 . The concept of the term acceleration as used herein includes deceleration. When the ink cartridge  10  moves with acceleration in the positive Y axis direction or negative Y axis direction, the inertia force is applied on the first stirring member  80 . As a result, the first stirring member  80  rotates around the projection  314 . That is, the movement with acceleration of the ink cartridge  10  including a component in the direction perpendicular to the first stirring member  80  (Y axis direction) causes the rotation of the first stirring member  80 . 
     Here, the first liquid container  40  is described as divided into an upper container  40   b  which is located above the projection  314  and a lower container  40   a  which is located below the upper container  40   b . In the initial state, the lower container  40   a  contains the pigment ink IK, while the upper container  40   b  contains the pigment ink IK and a predetermined amount of air EA. Specifically, the upper container  40   b  contains an enough amount of air EA to stir the pigment ink that is brought in proximity to the lower area of the upper container  40   b  by stirring of the first stirring member  80 . When the ink cartridge  10  is loaded in an on-carriage type printer that is commonly used, it is preferable that the upper container  40   b  contains air EA having a volume of 30% or more of the volume of the upper container  40   b , although it may vary depending on the degree of acceleration of the ink cartridge  10 . In this embodiment, the upper container  40   b  contains air EA having a volume of 30% of the volume of the upper container  40   b . In other words, the upper container  40   b  contains air EA having a volume of 8% of the entire volume of first liquid container  40 . 
       FIG. 8  is a view explaining a relationship between the first stirring member  80  and the bottom  402 .  FIG. 8  is a partial enlarged view enlarging the proximity of the bottom  402  of  FIG. 7B . The above description “the end  802  has a shape which generally corresponds to the entire area of the bottom  402 ” means that a length L 2  of the end  802  of the first stirring member  80  in the horizontal direction (X axis direction) is 70% or more of a length L 1  of the bottom  402  of the first liquid container  40 . In this embodiment, the length L 2  is defined as 75% of the length L 1 . Moreover, the first stirring member  80  is arranged in the first liquid container  40  such that the end  802  is in proximity to the bottom  402 , thereby allowing the entire pigment ink in proximity to the bottom  402  to be flown upward. The above description “in proximity to” means that, in the vertical direction (Z axis direction) in the mounted position, a length L 4  (which corresponds to lengths L 4   a , L 4   b  of  FIG. 8 ) extending from the end  802  to the bottom  402  that opposes the end  802  is 30% or less of a length L 3  (which corresponds to lengths L 3   a , L 3   b  of  FIG. 8 ) extending from the contact point where the first stirring member  80  is in contact with the projection  314  to the end  802  (the position of the contact point in the vertical direction is indicated by the dashed dotted line TL in the  FIG. 8 ). In  FIG. 8 , the length from the contact point to the first end  802   a  is indicated by L 3   a  and the length from the first end  802   a  to the bottommost part of the bottom  402   a  which opposes to the first end  802   a  is indicated by L 4   a . Further, the length from the contact point to the second end  802   b  is indicated by L 3   b  and the length from the second end  802   b  to the upper part of the bottom  402   b  which opposes to the second end  802   b  is indicated by L 4   b . It is preferable that the first stirring member  80  is arranged such that a narrow gap is formed between the bottom  402  and the end  802  so as to avoid them from coming in contact with each other, thereby allowing the entire pigment ink in proximity to the bottom  402  to be flown upward with a high certainty. 
       FIG. 9  is a view explaining a stirring state of the first liquid container  40 .  FIG. 9A  is a sectional view taken along the line IXA-IXA of  FIG. 6 , which shows the ink cartridge  10  is mounted in the carriage  12  ( FIG. 1 ) with the carriage  12  being in a stationary state.  FIG. 9B  is a sectional view taken along the line IXA-IXA of  FIG. 6 , which shows the carriage  12  is accelerating to the negative Y axis direction.  FIG. 9C  is a sectional view taken along the line IXA-IXA of  FIG. 6 , which shows the carriage  12  is accelerating to the positive Y axis direction.  FIG. 9D  shows the flowing state of the pigment ink in the first liquid container  40 , which is caused by acceleration of the carriage  12 . In  FIGS. 9A  to D, part of the configuration that does not need to be explained is not shown. 
     As shown in  FIG. 9A , in the initial state of the ink cartridge  10 , when the ink cartridge  10  is mounted in the carriage  12 , the lower container  40   a  contains the pigment ink IK and the upper container  40   b  contains the pigment ink IK and air EA. From this state, the carriage  12  start to reciprocate (accelerate) to the direction perpendicular to the first side  403  (Y axis direction) in response to meeting predetermined requirements. Such requirements include, as part of the requirements, that a controller of the printer  1  has sent a printing command, that the ink cartridge  10  has been replaced by new ink cartridge  10  and that a predetermined time has elapsed after the carriage  12  had last reciprocated, thereby variation in the concentration of the pigment ink is highly possible to occur. 
     As shown in  FIG. 9B , when the carriage  12  accelerates to the negative Y axis direction, the inertia force acting in the direction opposite to the acceleration direction (positive Y axis direction) is applied on the first stirring member  80  and the pigment ink IK. As a result, the first stirring member  80  rotates to the positive Y axis direction while the pigment ink IK in the upper container  40   b  moves to the positive Y axis direction. 
     As shown in  FIG. 9C , when the carriage  12  accelerates to the positive Y axis direction, the inertia force acting in the negative Y axis direction is applied on the first stirring member  80  and the pigment ink IK. As a result, the first stirring member  80  rotates to the negative Y axis direction while the pigment ink IK in the upper container  40   b  moves to the negative Y axis direction. 
     As shown in  FIG. 9D , the pigment ink IK in the lower container  40   a  is stirred by the first stirring member  80  and flown across the entire area in the lower container  40   a . Specifically, the pigment ink IK with the higher concentration, which is brought in proximity to the bottom  402  by stirring of the first stirring member  80 , is flown up above the first support member  310 . The pigment ink IK in the upper container  40   b  is flown across the entire area in the upper container  40   b  by movement of itself. 
     As described above, the pigment ink IK with the higher concentration in proximity to the bottom  402  in the first liquid container  40  is flown up above the first support member  310  by the first stirring member  80 , and the flown up pigment ink IK moves in the upper container  40   b  so as to be flown across the entire area in the upper container  40   b . Therefore, the first stirring member  80  can efficiently stir the pigment ink in the first liquid container  40  of a vertically long shape without having a height corresponding to the height of the first liquid container  40 . This makes it possible to reduce the variation in the concentration of the pigment ink IK in the first liquid container  40  while allowing the first stirring member  80  to be more compact. 
       FIG. 10  is a view explaining a configuration of the second liquid container  50 .  FIG. 10A  is a sectional view taken along the line XA-XA of  FIG. 6  with part of the configuration that does not need to be explained not being shown.  FIG. 10B  is a view of the second liquid container  50  seen from the positive Y axis direction with part of the configuration that does not need to be explained not being shown. That is,  FIG. 10B  corresponds to a view in which the second stirring member  90  is directly projected on the first side, which is described later. In the initial state of the ink cartridge  10 , the second liquid container  50  is filled with the pigment ink IK. 
     As shown in  FIG. 10A , the second liquid container  50  is an area defined by a bottom  502  which is located at a vertically lower position, a top  508  which is located vertically above the bottom  502  so as to oppose the bottom  502  and a first side  503  perpendicular to the bottom  502  and extends upwardly from the bottom  502  in the mounted position. The first side  503  is formed of the same member as that of the first side  403  ( FIG. 7A ) of the first liquid container  40  such that the first side  403  of the first liquid container  40  is flush with the first side  503  of the second liquid container  50 . The first side  503  is positioned so as to oppose the plate surface of the second stirring member  90 . A side  501  which opposes the first side  503  is entirely open. As shown in  FIG. 10B , the second liquid container  50  is further defined by a first member side  504  and a second member side  506  which both extend upwardly from the bottom  502 . The bottom  502  is step-shaped having a bottommost part of the bottom  502   a  and an upper part of the bottom  502   b . The bottommost part of the bottom  502   a  is a plane located at the bottommost position of the bottom  502  and substantially parallel to the direction perpendicular to the vertical direction and parallel to the first side  503  (also referred to as “horizontal direction”). The upper part of the bottom  502   b  is a plane located at the topmost position of the bottom  502  and substantially parallel to the horizontal direction. The second stirring member  90  has an end  902  which opposes the bottom  502 . Specifically, the second stirring member  90  has a first end  902   a  which opposes the bottommost part of the bottom  502   a  and a second end  902   b  which opposes the upper part of the bottom  502   b . The “the bottom  502 ” corresponds to “the second bottom” described in the summary section herein and “the first side  503 ” corresponds to “the second side” described in the summary section herein. 
     As shown in  FIG. 10A , two second support members  320  (one of them is shown in the figure) which extend from the first side  503  toward the open side are formed in the second liquid container  50 . The second support member  320  is formed in the same configuration as that of the first support member  310  ( FIG. 7A ) of the first liquid container  40 , therefore the same reference numerals are used for similar elements to avoid duplication of description. 
     The second stirring member  90  has a shape which allows the entire pigment ink in proximity to the bottom  502  to be flown across the entire area in the second liquid container  50 . Specifically, the second stirring member  90  is formed in a shape to cover the first side  503 . Further, the end  902  of the second stirring member  90  which opposes the bottom  502  has a shape which generally corresponds to the entire area of the bottom  502 . Moreover, the second stirring member  90  is arranged in the second liquid container  50  such that the end  902  is in proximity to the bottom  502 . 
     The above description “the second stirring member  90  is formed in a shape to cover the first side  503 ” means that the plate surface of the second stirring member  90  has a surface area of 50% or more of the surface area of the first side  503 . In this embodiment, the plate surface of the second stirring member  90  has a surface area of 55% of the surface area of the first side  503 . Further, the above description “the end  902  has a shape which generally corresponds to the entire area of the bottom  502 ” means that, for example, as shown in  FIG. 10B , a length L 6  of the end  902  of the second stirring member  90  in the horizontal direction (X axis direction) is 70% or more of a length L 5  of the bottom  502  of the second liquid container  50 . In this embodiment, the length L 6  is defined as 75% of the length L 5 . The above description “in proximity to” means that, in the vertical direction (Z axis direction) in the mounted position, a length L 8  (which corresponds to lengths L 8   a , L 8   b  of  FIG. 10B ) extending from the end  902  to the bottom  502  that opposes the end  902  is 30% or less of a length L 7  (which corresponds to lengths L 7   a , L 7   b  of  FIG. 10B ) extending from the contact point where the second stirring member  90  is in contact with the projection  314  to the end  902  (the position of the contact point in the vertical direction is indicated by the dashed dotted line TM in the  FIG. 10B ). In  FIG. 10B , the length from the contact point to the first end  902   a  is indicated by L 7   a  and the length from the first end  902   a  to the bottommost part of the bottom  502   a  which opposes to the first end  902   a  is indicated by L 8   a . Further, the length from the contact point to the second end  902   b  is indicated by L 7   b  and the length from the second end  902   b  to the upper part of the bottom  502   b  which opposes to the second end  902   b  is indicated by L 8   b . It is preferable that the second stirring member  90  is arranged such that a narrow gap is formed between the bottom  502  and the end  902  so as to avoid them from coming in contact with each other, thereby allowing the entire pigment ink in proximity to the bottom  902  to be flown upward with a high certainty. 
       FIG. 11  is a view explaining a stirring state of the second liquid container  50 .  FIG. 11A  is a fragmentary sectional view taken along the line XIA-XIA of  FIG. 6 , which shows the ink cartridge  10  is mounted in the carriage  12  ( FIG. 1 ) and the carriage  12  is reciprocating (accelerating).  FIG. 11B  shows the flowing state of the pigment ink in the second liquid container  50 , which is caused by acceleration of the carriage  12 , as indicated by the arrow. In  FIGS. 11A  and B, part of the configuration that does not need to be explained is not shown. 
     As shown in  FIG. 11A , when the carriage  12  accelerates to the Y axis direction, the inertia force is applied on the second stirring member  90 , thereby causing the second stirring member  90  to be rotated around the projection  314 . As a result, the pigment ink in proximity to the bottom  502  is flown upward. That is, as shown in FIG.  11 B, the pigment ink is allowed to be flown across the entire area in the second liquid container  50 . Accordingly, even if the second liquid container  50  of a horizontally long shape is disposed downstream of the first liquid container  40 , it is possible to reduce the variation in the concentration of the pigment ink in the second liquid container  50 . That is, even if the second liquid container  50  is disposed, the pigment ink with a uniform concentration can be supplied to the printer  1 . 
     As described above, in this embodiment, the upper container  40   b  contains the pigment ink and a predetermined amount of air ( FIG. 7A ) in the initial state such that the variation in the concentration of the pigment ink in the first liquid container  40  can be reduced while allowing the first stirring member  80  which is disposed in the first liquid container  40  having a vertically long shape to be more compact. 
     B. Variations of Embodiments 
     It should be noted that, among the elements described in the above embodiment, the elements not recited in the independent claims are additional elements and may be eliminated as appropriate. The invention is not limited to the above embodiment or example and can be implemented in various forms within the scope of the invention without departing from its principle. For example, the following variations can be implemented. 
     B-1. First and Second Variations 
       FIG. 12  is a view explaining first and second variations of embodiments.  FIG. 12A  is a view which explains the first variation and corresponds to  FIG. 7B . The first variation differs from the first embodiment in that it has different amount of air contained in the first liquid container  40  and different shape of the first stirring member  80   a  in the initial state. The configuration of the other elements (such as various flow channels formed in the case body  20 ) is the same as those described above, therefore the same reference numerals are used for similar elements to avoid duplication of description.  FIG. 12B  is a view which explains the second variation and corresponds to  FIG. 10B . The second variation differs from the first embodiment in that it has different shape of the second stirring member  90   a . The configuration of the other elements (such as various flow channels formed in the case body  20 ) is the same as those described above, therefore the same reference numerals are used for similar elements to avoid duplication of description. 
     B-1-1. Specific Description of First Variation 
     According to the first variation, in the initial state of the ink cartridge  10 , the first liquid container  40  contains 20% of the volume of the upper container  40   b . That is, according to the first variation, the first liquid container  40  contains air of a volume greater than that of the first embodiment in the initial state. The amount of the air contained corresponds to 30% of the volume of the upper container  40   b . When the amount of the air contained in the initial state is greater than that of the first embodiment, the range of movement of the pigment ink can be increased and the area to be stirred by the first stirring member  80   a  can be reduced. In other words, the greater amount of the air contained in the initial state makes it possible to reduce the variation in the concentration of the pigment ink in the first liquid container  40  while allowing the first stirring member  80   a  to be more compact. Particularly, the dimension in the height direction in the mounted position can be reduced. The amount of the air contained in the initial state is preferably 50% or less of the volume of the first liquid container  40  in order to ensure a certain amount of the pigment ink to be contained. 
     In the first embodiment, it is described that the end  802  has a shape which generally corresponds to the entire area of the bottom  402  ( FIG. 8 ), however the shape is not limited to this example. For example, as shown in  FIG. 12A , the shape may be formed such that it generally corresponds to the entire area of the bottommost part of the bottom  402   a . With this configuration, the pigment ink having highest concentration at least in the first liquid container  40 , which is located in proximity to the bottommost part of the bottom  402   a , can be stirred, therefore the variation in the concentration of the pigment ink in the first liquid container  40  can be reduced. In addition, in order to further reduce the variation in the concentration of the pigment ink in the first liquid container  40 , the surface area of the plate surface of the first stirring member  80  is preferably 50% or more, more preferably 55% or more, of the surface area of the part of the first side  403  ( FIG. 7 ) which is located in the lower container  40   a . That is, the first stirring member  80  preferably has a shape to cover the part of the first side  403  which is located in the lower container  40   a.    
     B-1-2. Specific Description of Second Variation 
     The second stirring member  90   a  in the second variation is formed such that it covers a part of the second liquid container  50  which is larger than the second stirring member  90  does in the first embodiment. Specifically, it covers 80% of the first side  503  ( FIG. 10A ). Therefore, when the second stirring member  90   a  covers the larger area of the second liquid container  50 , the second stirring member  90   a  can improve the flowability of the pigment ink in the second liquid container  50 , thereby enabling the variation in the concentration of the pigment ink in the first liquid container  40  to be further reduced. 
     B-2. Third Variation 
     In the first embodiment, it is described that the end  902  of the second stirring member  90  has a shape which generally corresponds to the entire area of the bottom  502  of the second liquid container  50  ( FIG. 10B ), however the shape is not limited to this example. At least, the end  902  may have a shape such that it corresponds to the entire area of the bottommost part of the bottom  502   a . With this configuration, the pigment ink having higher concentration, which is located in proximity to the bottommost part of the bottom  502   a , can be stirred, therefore the variation in the concentration of the pigment ink in the second liquid container  50  can be reduced. 
     B-3. Fourth Variation 
     In the first embodiment, the ink cartridge  10  is described as a type which is mounted in the carriage  12  ( FIG. 1 ) (so-called on-carriage type of cartridge), however other types of ink cartridge  10  may be used, such as that is mounted in a mounting section which is formed at a position other than the carriage  12  (so-called off-carriage type of cartridge). When the invention is applied to the off-carriage type cartridge, the pigment ink in the first and the second liquid containers  40  and  50  is stirred by periodically reciprocating (accelerating) the mounting section in a predetermined direction (the direction perpendicular to the stirring member). In addition, as long as the reciprocating motion includes at least a predetermined direction component, it may also include other direction component. 
     B-4. Fifth Variation 
     Although the first embodiment has been described by means of the ink cartridge  10  that is used in the printer  1  as an example of the liquid containing chamber, the invention is not limited to this example and also applicable to various liquid containing chambers. Particularly, the invention is advantageously applicable to the liquid containing chambers that contain a dispersion substance. The invention is applicable to a liquid containing chamber that is mounted in, for example, an apparatus having a color material ejecting head such as a liquid crystal display, an apparatus having an electrode material (conductive paste) ejecting head used for forming electrodes for an organic electroluminescence display, a field emission display (FED) and the like, an apparatus having a bioorganic ejection head used for manufacturing biochips, an apparatus having a sample ejection head as a fine pipette, a liquid ejecting apparatus such as a textile printing apparatus, a microdispenser and the like. 
     When a liquid containing chamber is used in the various liquid ejecting apparatuses as described above, a suitable liquid (such as color material, conductive paste and bioorganic material) may be contained in the liquid containing chamber depending on the type of liquid ejected from the liquid ejecting apparatus.