Patent Publication Number: US-10308032-B2

Title: Cartridge for liquid jetting apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority based on Japanese Patent Applications No. 2017-016534 filed on Feb. 1, 2017, the disclosures of which are hereby incorporated by reference in their entirety. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a cartridge and the like. 
     2. Related Art 
     Heretofore, inkjet printers have been known as examples of a liquid jetting apparatus. In inkjet printers, printing can be performed on a printing medium such as printing paper by discharging ink, which is an example of liquid, from a jetting head onto the printing medium. Regarding such inkjet printers, a mode is known in which ink contained in a cartridge is supplied to the jetting head. Heretofore, a configuration has been known in which such a cartridge has an ink container that contains ink, a case that houses the ink container, and an air bag arranged between an internal wall of the case and the ink container (for example, see JP-A-2016-187894). 
     JP-A-2016-187894 is an example of related art. 
     In the cartridge described in above JP-A-2016-187894, the air bag includes a first air bag and a second air bag. The first air bag and the second air bag are arranged in the front-back direction of the cartridge. The ink container extends from a position adjacent to the first air bag to a position adjacent to the second air bag. This configuration allows ink to flow in the front-back direction in the ink container by alternately expanding/contracting the first air bag and the second air bag, and thus the ink in the ink container can be agitated effectively. 
     Incidentally, the purpose of agitating ink is to reduce a difference in concentration in the up-down direction caused by gravity. In order to effectively reduce the difference in concentration in the up-down direction, a lower portion of the ink container is preferably pressed. However, in the above-described cartridge, the air bag that is inflated is unlikely to reach a lower portion of the ink container. This is partly because the above-described air bag of the cartridge is made of a so-called gusset-type bag having upper and lower gusset portions, and has a height substantially equivalent to that of the ink container in the up-down direction. In such an air bag, the peak of a bulge of the air bag is likely to be positioned at a central portion of the ink container in the up-down direction. Therefore, in the above-described cartridge, the inflated air bag is unlikely to reach a lower portion of the ink container. Thus, with the above-described cartridge, there is an issue in that it is hard to improve the agitation effect. The invention has been made in order to solve such an issue, and is aimed to provide a cartridge that makes it easier to improve the effect of agitating ink. 
     SUMMARY 
     The invention can be realized as the following modes or application examples. 
     APPLICATION EXAMPLE 1 
     A cartridge that is mounted to a liquid jetting apparatus that includes an air supply apparatus that supplies air and a liquid jetting unit that jets liquid, the cartridge includes a liquid container that contains the liquid, at least a portion of the liquid container being flexible, a case that includes the liquid container, and an air bag that is positioned between an internal wall of the case and the liquid container, at least a portion of which is flexible, and that contacts with the liquid container in a state of being expanded upon being supplied with the air, the air bag includes a first bag that is expanded upon being supplied with the air and a second bag that is positioned above the first bag when the cartridge is in use, and is expanded upon being supplied with the air, the air bag and the liquid container are aligned in a first direction intersecting an up-down direction when the cartridge is in use, and when the cartridge is in use, and the cartridge is viewed in the first direction, the first bag is arranged to overlap a lower part of the center in the up-down direction of the liquid container. 
     In this cartridge, the first bag of the air bag that includes the first bag and the second bag is arranged at a position overlapping a portion below the center in the up-down direction in the liquid container. Therefore, it is possible to bring the first bag into contact with the portion below the center in the up-down direction in the liquid container when the air bag is expanded upon receiving a supply of air. Accordingly, the expanded air bag easily reaches a lower portion of the liquid container. Thus, in this cartridge, the effect of agitating the liquid in the liquid container is easily improved. 
     APPLICATION EXAMPLE 2 
     In the above-described cartridge, the air bag includes a pillow-type bag, the pillow-type bag is divided into the first bag and the second bag. 
     In this cartridge, the air bag has a configuration in which a pillow-type bag is divided into the first bag and the second bag, and thus the air bag can be formed with a simple configuration. 
     APPLICATION EXAMPLE 3 
     In the above-described cartridge, the pillow-type bag includes a configuration in which edges of two overlapped film materials are joined through welding, and in a joint portion formed through welding, notch portions are formed in a portion adjacent to the first bag in a direction intersecting the up-down direction and the first direction, and a portion adjacent to the second bag in the direction intersecting the up-down direction and the first direction. 
     In this cartridge, in the joint portion of the pillow-type bag, the notch portions are respectively formed in a portion adjacent to the first bag and a portion adjacent to the second bag in the direction intersecting the up-down direction and the first direction. Here, when the pillow-type bag is inflated, the joint portion formed through welding is likely to be resistant to inflation and deformation of the bag, and thus the shape of the bag when inflated is unlikely to be stable at a fixed shape. If this occurs, a mode in which the liquid container is pressed by the air bag is likely to change every time the liquid container is pressed, and thus a stable agitation effect is unlikely to be acquired. In this regard, with the above-described cartridge, deformation of the joint portion is likely to be concentrated on the notch portions, and thus the shape of the pillow-type bag when inflated is likely to be stabilized at a fixed shape. As a result, a stable agitation effect is easily acquired, and thus it is possible to easily improve the agitation effect further. 
     APPLICATION EXAMPLE 4 
     In the above-described cartridge, an introduction port for introducing the air into the air bag is included so as to be shared by the first bag and the second bag, an introduction path that branches into the first bag and the second bag from the introduction port is formed in the pillow-type bag, and the introduction path includes a configuration in which surface press molding has been performed on at least one film material out of the two film materials. 
     In this cartridge, the introduction path formed in the pillow-type bag has a configuration in which surface press molding has been performed on at least one film material out of the two film materials, and thus it is easy to avoid blockage of the introduction path due to the two film materials adhering to each other. Accordingly, the shape of the pillow-type bag when inflated is likely to be stabilized at a fixed shape. As a result, a stable agitation effect is easily acquired, and it is possible to easily further improve the agitation effect. 
     APPLICATION EXAMPLE 5 
     In the above-described cartridge, a second air bag that is expanded upon being supplied with the air is provided, the liquid container is divided into a first container and a second container, the first container and the second container are aligned in a second direction intersecting the up-down direction and the first direction, and are communicated with each other at a lower part of the center in the up-down direction of the liquid container, and the first air bag is arranged at a position opposing the first container, and the second air bag is arranged at a position opposing the second container. 
     In this cartridge, in the liquid container that is divided into the first container and the second container, the first container can be pressed by the first air bag, and the second container can be pressed by the second air bag. 
     APPLICATION EXAMPLE 6 
     In the above-described cartridge, the liquid container is a flexible bag, and is divided into the first container and the second container by a clamping member that clamps a portion of the bag from outside the bag. 
     In this cartridge, due to the clamping member clamping a portion of the bag, the bag can be divided into the first container and the second container. 
     APPLICATION EXAMPLE 7 
     In the above-described cartridge, the clamping member includes a clamping portion that clamps the bag and an expansion holding portion that configures to communicate with the first container and the second container each other, by holding a portion of the bag in a state of being expanded, and a rigidity member configures to heighten rigidity of the bag, the rigidity member is joined to a portion of the bag overlapping with the expansion holding portion. 
     In this cartridge, the rigidity of the portion of the bag that is expanded by the expansion holding portion is improved, and thus the expanded portion of the bag is likely to be held in a state of being expanded. Therefore, communication between the first container and the second container is easily maintained. 
    
    
     
       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 perspective view schematically showing a main configuration of a liquid jetting system in an embodiment of the invention. 
         FIG. 2  is a perspective view showing a cartridge in the embodiment. 
         FIG. 3  is a perspective view showing the cartridge in the embodiment. 
         FIG. 4  is a perspective view schematically showing a main configuration of the liquid jetting system in the embodiment. 
         FIG. 5  is an exploded perspective view showing the cartridge in the embodiment. 
         FIG. 6  is an exploded perspective view showing a pack assembly in the embodiment. 
         FIG. 7  is an exploded perspective view showing a pack unit in the embodiment. 
         FIG. 8  is a perspective view showing the ink pack in the embodiment. 
         FIG. 9  is an external view showing a clamping member in the embodiment. 
         FIG. 10  is a cross-sectional view of the pack unit in the embodiment. 
         FIG. 11  is an external view showing a first air bag in the embodiment. 
         FIG. 12  is an exploded perspective view showing the first air bag in the embodiment. 
         FIG. 13  is a perspective view showing the first air bag in the embodiment. 
         FIG. 14  is an external view showing a first case, the first air bag, and a second air bag in the embodiment. 
         FIG. 15  is a perspective view partially showing the first case in the embodiment. 
         FIG. 16  is an external view showing the first case, the first air bag, and the second air bag in the embodiment. 
         FIG. 17  is an external view showing the first case, the first air bag, the second air bag, and the pack assembly in the embodiment. 
         FIG. 18  is an external view showing the first case, the first air bag, the second air bag, and the pack assembly in the embodiment. 
         FIG. 19  is a cross-sectional view of the cartridge in the embodiment when cut along a line equivalent to a line B-B in  FIG. 1 . 
         FIG. 20  is a perspective view showing the first case, the pack assembly, a first spacer, and a second spacer in the embodiment. 
         FIG. 21  is a perspective view showing the first case, the pack assembly, and a tube in the embodiment. 
         FIG. 22  is an exploded perspective view showing the cartridge in the embodiment. 
         FIG. 23  is an exploded perspective view showing another example of the ink pack in the embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     An embodiment of a printing apparatus will be described while taking a liquid jetting system as an example, with reference to the drawings. Note that, in the drawings, the scale of constituent parts and members may be different such that the respective constituent parts are shown with a recognizable size. 
     A liquid jetting system  1  in this embodiment has a printer  3  that is an example of a liquid jetting apparatus and an ink supply apparatus  4  that is an example of a printing material supply apparatus, as shown in  FIG. 1 . The printer  3  has a conveyance apparatus  5 , a printing unit  6 , a movement apparatus  7 , and a control unit  11 . 
     Here, in  FIG. 1 , X, Y, and Z axes that are coordinate axes orthogonal to each other are given. In the figures shown hereinafter, the X, Y, and Z axes are given as necessary. In this case, the X, Y, and Z axes in the drawings correspond to the X, Y, and Z axes  FIG. 1 .  FIG. 1  illustrates a state where the liquid jetting system  1  is arranged on an XY plane defined by the X axis and the Y axis. In this embodiment, a state where the liquid jetting system  1  is arranged on the XY plane when the XY plane is made to match a horizontal flat face is an in-use state of the liquid jetting system  1 . The orientation of the liquid jetting system  1  when the liquid jetting system  1  is arranged on the XY plane that is made to match a horizontal face is called a usage orientation of the liquid jetting system  1 . 
     Note that the horizontal face may be a substantially horizontal face. The substantially horizontal face includes an inclination within the range of an inclination of a face recommended for use of the liquid jetting system  1 , for example. Accordingly, the substantially horizontal face is not limited to a face of a highly accurately formed surface plate or the like. Examples of the substantially horizontal face include various surfaces of a desk, a mounting stool, a shelf, and a floor on which the liquid jetting system  1  is placed for use. 
     In the following description, when the X axis, the Y axis, and the Z axis are given in diagrams or description illustrating constituent parts and units of the liquid jetting system  1 , the X axis, the Y axis, and the Z axis in a state where the constituent parts and units are incorporated (mounted) in the liquid jetting system  1  are meant. In addition, the orientations of the constituent parts and units in the usage orientation of the liquid jetting system  1  are referred to as usage orientations of those constituent parts and units. Hereinafter, the liquid jetting system  1 , the constituent parts and units thereof, and the like are described as being in their usage orientations, unless specifically stated otherwise. 
     The Z axis is an axis orthogonal to the XY plane. In the in-use state of the liquid jetting system  1 , the Z axis direction is the vertical upward direction. Also, in the in-use state of the liquid jetting system  1 , in  FIG. 1 , a −Z axis direction is the vertical downward direction. Note that for each of the X, Y, and Z axes, the direction of an arrow indicates a + (positive) direction, and a direction opposite to the direction of the arrow indicates a − (negative) direction. In addition, the vertically upward direction or “vertically above” refer to the upward direction or “above” along the vertical line. Similarly, the vertical downward direction or “vertically below” refer to the downward direction or “below” along the vertical line. An upward direction or “above” without “vertically” is not limited to the upward direction or “above” along the vertical line, and includes an upward direction or “above” along a direction intersecting the vertical line, except for the horizontal direction. Also, a downward direction or “below” without “vertically” is not limited to the downward direction or “below” along the vertical line, and includes a downward direction or “below” along a direction intersecting the vertical line, except for the horizontal direction. 
     The conveyance apparatus  5  intermittently conveys a printing medium P such as recording paper in the Y axis direction. The printing unit  6  performs recording on the printing medium P conveyed by the conveyance apparatus  5 , using ink that is an example of a liquid. The movement apparatus  7  reciprocally moves the printing unit  6  along the X axis. The ink supply apparatus  4  supplies ink to the printing unit  6 . The control unit  11  controls driving of the above-described constituent elements. 
     The conveyance apparatus  5  has a driving roller  12 A, a driven roller  12 B, and a conveyance motor  13  as shown in  FIG. 1 . The driving roller  12 A and the driven roller  12 B are configured to be rotatable with their outer circumferential surfaces being in contact with each other. The conveyance motor  13  generates motive power for rotatively driving the driving roller  12 A. The motive power from the conveyance motor  13  is transmitted to the driving roller  12 A via a transmission mechanism. The printing medium P clamped between the driving roller  12 A and the driven roller  12 B is then intermittently conveyed in the Y axis direction. 
     The printing unit  6  has four relay units  15 , a carriage  17 , and a printing head  19 . The relay units  15  relay ink supplied from the ink supply apparatus  4  to the printing head  19 . The printing head  19  is an example of a liquid jetting unit, and discharges ink as ink droplets so as to perform recording on the printing medium P. The carriage  17  is equipped with the four relay units  15  and the printing head  19 . Note that the printing head  19  is connected to the control unit  11  via a flexible cable  21 . The discharge of ink droplets from the printing head  19  is controlled by the control unit  11 . 
     The movement apparatus  7  has a timing belt  23 , a carriage motor  24 , and a guiding shaft  25  as shown in  FIG. 1 . The timing belt  23  is stretched between a pair of pulleys  22 A and  22 B. The pair of pulleys  22 A and  22 B are aligned along the X axis. Therefore, the timing belt  23  is stretched along the X axis. The carriage motor  24  generates motive power for rotatively driving the pulley  22 A. The guiding shaft  25  extends along the X axis. The two ends of the guiding shaft  25  are supported by a box (not illustrated), and the guiding shaft  25  guides the carriage  17  along the X axis. 
     The carriage  17  is fixed to a portion of the timing belt  23 . Motive power is transmitted from the carriage motor  24  to the carriage  17  via the pulley  22 A and the timing belt  23 . Also, the carriage  17  is configured to be able to reciprocally move along the X axis using the transmitted motive power. 
     As shown in  FIG. 1 , cartridges  26  are detachably mounted to the ink supply apparatus  4 . Also, the ink supply apparatus  4  has a holder  27  that is an example of a mounting portion, and a pump unit  29 . Note that in this embodiment, a plurality of (in this embodiment, four) cartridges  26  can be mounted to the ink supply apparatus  4 . The four cartridges  26  are detachably supported by the holder  27 . A pack unit (which will be described later) that is an example of a liquid containing body is housed in each of the cartridges  26 . The pack unit has an ink container that is an example of a liquid container. Ink is sealed in the ink container made of a flexible film material. 
     An ink supply tube  28  is connected to the pack unit in the cartridge  26 . The ink supply tube  28  that is an example of a channel member is connected to each of the relay units  15  from the ink supply apparatus  4 . The four relay units  15  are respectively connected to the pack units of the cartridges  26  via the ink supply tubes  28 . In the process of supplying ink from the cartridges  26  to the respective relay units  15 , pressure is applied by the pump unit  29  to ink in the cartridges  26 . Due to this, the ink in the cartridges  26  is sent to the relay units  15  via the ink supply tubes  28 , respectively. Accordingly, the supply of ink from the ink supply apparatus  4  to the printing head  19  can be assisted using the pump unit  29 . 
     In this manner, ink in the cartridges  26  is supplied from the ink supply apparatus  4  to the printing head  19  via the relay units  15 . The ink supplied to the printing head  19  is then discharged as ink droplets from nozzles (not illustrated) directed toward the printing medium P. Note that in the above example, a description was given in which the printer  3  and the ink supply apparatus  4  have separate configurations, but the ink supply apparatus  4  can be included in the configuration of the printer  3 . Also, the ink supply apparatus  4  and the pump unit  29  can have separate configurations. Note that driving of the pump unit  29  is controlled by the control unit  11 . 
     In the liquid jetting system  1  that has the above-described configuration, driving of the conveyance motor  13  is controlled by the control unit  11 , and the conveyance apparatus  5  intermittently conveys the printing medium P in the Y axis direction such that the printing medium P faces the printing head  19 . At this time, the control unit  11  controls driving of the printing head  19  so as to discharge ink droplets at a predetermined position while controlling driving of the carriage motor  24  so as to reciprocally move the carriage  17  along the X axis. Due to such an operation, dots are formed on the printing medium P, and recording that is based on recording information such as image data is performed on this printing medium P. Note that the configuration of the liquid jetting system  1  is not limited to a configuration in which the carriage  17  that can move the printing head  19  along the X axis is included. As the liquid jetting system  1 , a mode of a line head type can also be adopted in which the printing head  19  is arranged over the width along the X axis of the printing medium P. 
     Each cartridge  26  has a case  41  as shown in  FIG. 2 . Each cartridge  26  has a long shape with a longitudinal dimension of approximately 550 mm along the Y axis and a height dimension of approximately 100 mm along the Z axis, for example. 
     The case  41  constitutes the outer shell of the cartridge  26 . The case  41  has a front face  42 , a lower face  43 , and a side face  44 . The front face  42 , the lower face  43 , and the side face  44  intersect each other. As shown in  FIG. 3 , the case  41  also has a rear face  45 , an upper face  46 , and a side face  47 . The rear face  45 , the upper face  46 , and the side face  47  intersect each other. The front face  42  also intersects the upper face  46  and the side face  47 . The rear face  45  also intersects the lower face  43  and the side face  44 . In addition, the front face  42  and the rear face  45  oppose each other. The lower face  43  and the upper face  46  oppose each other. The side face  44  and the side face  47  oppose each other. Note that the front face  42  is positioned at the end portion in a −Y axis direction of the cartridge  26 . The rear face  45  is positioned at the end portion in a +Y axis direction of the cartridge  26 . In other words, in the cartridge  26 , the front face  42  is positioned at one end, and the rear face  45  is positioned at the other end. Note that the front face  42  corresponds to a first face, the rear face  45  corresponds to a second face, the lower face  43  corresponds to a third face, and the upper face  46  corresponds to a fourth face. 
     The front face  42 , the lower face  43 , the side face  44 , the rear face  45 , the upper face  46 , and the side face  47  are not limited to flat faces, and may include uneven or curved surfaces. In addition, two faces intersecting each other do not need to be orthogonal to each other, and it suffices for the two faces intersecting each other to have a positional relationship of intersecting each other. Two faces intersecting each other means that the two faces have a positional relationship of not being parallel to each other. Thus, the invention is not limited to a configuration in which two faces intersecting each other come into direct contact, and a configuration can also be adopted in which two faces intersecting each other intersect via another flat face or a curved face. Specifically, in addition to a case where two faces are in direct contact with each other, a case where two faces have a relationship in which the extension of one of the two faces intersects the extension of the other is also expressed as “intersecting”, even if the two faces have a positional relationship of not being in direct contact with each other and being apart from each other. In addition, an angle formed by two intersecting faces may be any one of a right angle, an obtuse angle, and an acute angle. 
     As shown in  FIG. 2 , a supply port  48 , a pressurization port  49 , a first air inlet port  51 , and a second air inlet port  52  are provided in the front face  42  of the case  41 . The supply port  48  is provided as an opening formed in the case  41 . As shown in  FIG. 4 , when a cartridge  26  is mounted to the holder  27 , the cartridge  26  is inserted from the supply port  48  side, in other words, from the front face  42  side into the holder  27 . At this time, the front face  42  of the cartridge  26  is inserted from an opening  53  of the holder  27  into the holder  27 . 
     Here, the direction in which the cartridge  26  is inserted into the opening  53  of the holder  27  is expressed as an insertion direction S 1 . Also, the direction in which the cartridge  26  is pulled out from the holder  27  is expressed as a pull-out direction S 2 . When the cartridge  26  is inserted into the opening  53  of the holder  27 , the front face  42  faces in the insertion direction S 1 . In addition, the opening  53  of the holder  27  is open in the pull-out direction S 2 , which is the opposite direction to the insertion direction S 1 . 
     Here, the front face  42  facing in the insertion direction S 1  refers to a state where the front face  42  and the insertion direction S 1  are not parallel. The state where the front face  42  faces in the insertion direction S 1  is not limited to a state where an angle formed by the front face  42  and the insertion direction S 1  is exactly perpendicular, and includes a state where the angle formed by the front face  42  and the insertion direction S 1  is an acute angle or an obtuse angle. Similarly, the opening  53  of the holder  27  being open in the pull-out direction S 2  refers to a state where a face defined by the outline of the opening  53  and the pull-out direction S 2  are not parallel. The state where the opening  53  is open in the pull-out direction S 2  is not limited to a state where an angle formed by the face defined by the outline of the opening  53  and the pull-out direction S 2  is exactly perpendicular, and includes a state where the angle is an acute angle or an obtuse angle. In this specification, the expression that a face faces a predetermined direction is not limited to a state where an angle formed by the face and the predetermined direction is exactly perpendicular, and includes a state where the angle is an acute angle and an obtuse angle. 
     Note that in this embodiment, the insertion direction S 1  is the −Y axis direction, and the pull-out direction S 2  is the +Y axis direction. Accordingly, in this embodiment, the insertion direction S 1  and the pull-out direction S 2  are along the Y axis. However, the insertion direction S 1  and the pull-out direction S 2  are not limited thereto, and a mode can also be adopted in which the insertion direction S 1  is the +Y axis direction, and the pull-out direction S 2  is the −Y axis direction. In addition, as the insertion direction S 1  and the pull-out direction S 2 , various directions can be adopted such as a direction along the X axis, a direction along the Z axis, and directions respectively intersecting the X axis, the Y axis, and the Z axis. 
     In the ink supply apparatus  4 , the supply port  48  of the cartridge  26  and the ink supply tube  28  are connected in the holder  27  when the cartridge  26  is mounted to the holder  27 . The pump unit  29  is also connected to the pressurization port  49  ( FIG. 2 ), the first air inlet port  51 , and the second air inlet port  52 . The pressurization port  49 , the first air inlet port  51 , and the second air inlet port  52  are introduction ports that introduce, into the case  41 , atmospheric air that is sent in from the pump unit  29 , and are connection ports to the pump unit  29 . The pump unit  29  is an example of an air supply apparatus that can supply atmospheric air that is an example of air to the cartridge  26 . 
     The case  41  includes a first case  61  and a second case  62  as shown in  FIG. 3 . Also, the cartridge  26  has an air bag set  63 , a pack assembly  64 , a first spacer  66 , a second spacer  68 , and a sheet member  69  as shown in  FIG. 5 . The first case  61  and the second case  62  are adjacent to each other in the X axis direction. The pack assembly  64  is arranged between the first case  61  and the second case  62 . The air bag set  63  is arranged between the first case  61  and the pack assembly  64 . The sheet member  69  is arranged between the pack assembly  64  and the second case  62 . 
     The first case  61  has a first wall  71 , a second wall  72 , a third wall  73 , a fourth wall  74 , and a fifth wall  75  as shown in  FIG. 5 . The first wall  71  intersects the X axis direction, and faces toward the second case  62 . The second wall  72 , the third wall  73 , the fourth wall  74 , and the fifth wall  75  each intersect the first wall  71 . When the first wall  71  is seen in planar view from the sheet member  69  side, the first wall  71  is surrounded by the second wall  72 , the third wall  73 , the fourth wall  74 , and the fifth wall  75 . 
     The second wall  72  and the third wall  73  are provided at positions opposing each other so as to sandwich the first wall  71  in the Y axis direction. The fourth wall  74  and the fifth wall  75  are provided at positions opposing each other so as to sandwich the first wall  71  in the Z axis direction. The second wall  72  intersects the fourth wall  74  and the fifth wall  75 . The third wall  73  also intersects the fourth wall  74 , and the fifth wall  75 . The second wall  72 , the third wall  73 , the fourth wall  74  and the fifth wall  75  protrude from the first wall  71  in a +X axis direction. Accordingly, with the first wall  71  serving as a main wall, a housing recess  76  is constituted by the second wall  72 , the third wall  73 , the fourth wall  74 , and the fifth wall  75  that extend from the main wall in the +X axis direction. 
     The housing recess  76  is configured in a direction to be recessed in a −X axis direction. The housing recess  76  is open in the +X axis direction, namely, on the sheet member  69  side. In other words, the housing recess  76  is provided in a direction so as to be recessed on the side opposite to the sheet member  69  side. A joint portion  77  is provided in the edge portion in the X axis direction of the first case  61 . The joint portion  77  is provided in the end portions in the X axis direction of the second wall  72  to the fifth wall  75 . The joint portion  77  is continuous along the second wall  72  to the fifth wall  75  of the first case  61 . The sheet member  69  has a size and shape so as to cover the housing recess  76  of the first case  61  when seen in planar view from the second case  62  side. 
     In planar view of the first case  61  from the second case  62  side, the joint portion  77  surrounds the housing recess  76 . The sheet member  69  is joined to the joint portion  77 . The air bag set  63 , the pack assembly  64 , the first spacer  66 , and the second spacer  68  are housed in a space surrounded by the sheet member  69  and the housing recess  76 . In this embodiment, the sheet member  69  is joined to the joint portion  77  through welding. The airtightness in the housing recess  76  is improved by the sheet member  69 . Accordingly, the housing recess  76  is sealed by the sheet member  69 . 
     The second case  62  is provided on the opposite side to the first case  61  side of the sheet member  69  as shown in  FIG. 5 . The second case  62  has a size and shape so as to cover the housing recess  76  of the first case  61  when the first case  61  is seen in planar view from the second case  62  side. The second case  62  covers the entirety of the sheet member  69 , including the housing recess  76  of the first case  61 . Accordingly, the air bag set  63 , the pack assembly  64 , the first spacer  66 , the second spacer  68 , and the sheet member  69  are housed between the first case  61  and the second case  62 . 
     The aforementioned supply port  48 , pressurization port  49 , first air inlet port  51 , and second air inlet port  52  are provided in the second wall  72  of the first case  61 . The supply port  48  penetrates the second wall  72 . Therefore, the supply port  48  reaches the inside of the housing recess  76 . The pressurization port  49 , the first air inlet port  51 , and the second air inlet port  52  are provided in the second wall  72  on the fifth wall  75  side relative to the supply port  48 . A channel that brings the pressurization port  49 , the first air inlet port  51 , and the second air inlet port  52  into communication with each other is provided piercing the second wall  72 , in the housing recess  76 . Atmospheric air that is sent in from the pump unit  29  ( FIG. 1 ) passes through the channel of the pressurization port  49 , the first air inlet port  51 , and the second air inlet port  52 , and is introduced into the housing recess  76 . Note that the first wall  71  to the fifth wall  75  are not limited to a flat wall, and may be walls that include unevenness. 
     The housing recess  76  of the first case  61  houses the air bag set  63 , the pack assembly  64 , the first spacer  66 , and the second spacer  68 . The air bag set  63  is arranged between the pack assembly  64  and the first wall  71  that is an example of an internal wall of the case  41  ( FIG. 3 ). Here, the pack assembly  64  has an ink container  78 . Ink is contained in the ink container  78 . The air bag set  63  is arranged between the first wall  71  of the first case  61  and the ink container  78 . 
     As shown in  FIG. 6 , the pack assembly  64  has a pack unit  81  and four spacers  82 . The pack unit  81  has a bag  84 . Gusset portions  85  are formed in the bag  84 . The four spacers  82  each have a shape corresponding to the shape of the corresponding gusset portion  85  of the bag  84 , and are fixed to the bag  84  using tape  86  in a state of being inserted into the gusset portions  85 . A configuration in which the spacers  82  are incorporated in the pack unit  81  is equivalent to the pack assembly  64 . 
     As shown in  FIG. 7 , the pack unit  81  includes an ink pack  91  and a clamping member  92 . A configuration in which the clamping member  92  is mounted on the ink pack  91  is equivalent to the pack unit  81 . The ink pack  91  has a connection unit  93  and the bag  84 . The bag  84  is made of a flexible film member, and the film member is joined in a bag-like shape. Ink is contained in the bag  84 . In this embodiment, the bag  84  is formed by joining the film member through welding. The connection unit  93  is joined to the bag  84  at a joint portion  95  of the bag  84 . Note that the bag  84  that is formed in a bag-like shape forms the ink container  78 . A configuration in which the bag  84  and the connection unit  93  are joined is equivalent to the ink pack  91 . 
     As modes of the bag  84 , various modes such as a pillow-type bag, a standing pouch-type bag, and a gusset-type bag can be adopted. In this embodiment, a gusset-type bag is adopted as the bag  84  as shown in  FIG. 8 . The bag  84  has a joint portion  95 , and is formed by joining one film member at the joint portion  95  into a bag-like shape. In the gusset-type bag  84 , the joint portion  95  is provided at peripheral edges. Two gusset portions  97  are formed in the gusset-type bag  84 . The two gusset portions  97  oppose each other along the Z axis. 
     The connection unit  93  has a function as a connection portion that enables connection between the ink container  78  and the ink supply tube  28  in the holder  27  when the cartridge  26  is mounted to the holder  27  ( FIG. 4 ). The connection unit  93  penetrates the joint portion  95 , and is inserted from outside of the bag  84  into the bag  84 . The connection unit  93  and the bag  84  are joined to each other at the joint portion  95 . The connection unit  93  protrudes from inside the bag  84  to outside the bag  84 . In the following description, a section of the joint portion  95  that intersects the connection unit  93  is expressed as a joint portion  95 A. 
     A channel that is in communication with the inside of the bag  84  and a valve for opening/closing the channel is provided within the connection unit  93 . Ink in the bag  84  is lead to the outside of the bag  84  through the channel provided in the connection unit  93 . In the ink pack  91  with the above-described configuration, the bag  84  is housed in the housing recess  76  in a state where the connection unit  93  is fitted in the supply port  48  from inside the housing recess  76  ( FIG. 5 ). Note that a sealing member is provided between the connection unit  93  and the supply port  48 . The airtightness between the connection unit  93  and the supply port  48  is improved by this sealing member. With the above-described configuration, the bag  84  in the housing recess  76  is easily pressurized by the pump unit  29 . 
     A portion for connection (not illustrated) that is connected to the connection unit  93  is provided in the holder  27  shown in  FIG. 4 . The portion for connection is connected to the ink supply tube  28 . When the cartridge  26  is mounted to the holder  27 , the connection unit  93  and the portion for connection are connected to each other, in the holder  27 . Accordingly, ink in the ink container  78  is supplied from the connection unit  93  to the ink supply tube  28  via the portion for connection. 
     The clamping member  92  clamps the bag  84  from outside as shown in  FIG. 7 . The clamping member  92  clamps the bag  84  from outside so as to extend around the bag  84 . Therefore, in the pack unit  81 , due to the bag  84  being clamped by the clamping member  92 , one of the gusset portions  97  is sectioned into two gusset portions  85 . The spacers  82  ( FIG. 6 ) are respectively inserted into four gusset portions  85 . The spacers  82  are inserted into the gusset portions  85 , and thus it is possible to maintain a state where the gusset portions  85  are open. Accordingly, it is easy to avoid fatigue destruction of the film material due to repetitive deformation when the gusset portions  85  shrink and open. Also, it is possible to prevent ink from staying in the periphery of the gusset portions  85  when agitating ink in the bag  84  (which will be described later in detail). 
     In addition, as shown in  FIG. 7 , in the pack unit  81 , due to the bag  84  being clamped by the clamping member  92 , the ink container  78  is partitioned into a first container  78 A and a second container  78 B. Note that the first container  78 A and the second container  78 B are in communication with each other in a portion below the center in the height direction along the Z axis of the ink container  78 . The first container  78 A and the second container  78 B are aligned in a direction along the Y axis. Note that the height direction along the Z axis is equivalent to the up-down direction, and a direction along the X axis is equivalent to a first direction, and a direction along the Y axis is equivalent to a second direction. 
     As shown in  FIG. 9 , the clamping member  92  has a clamping portion  99  that clamps the bag  84  so as to sandwich one of the gusset portions  97  of the bag  84  ( FIG. 8 ), and an expansion holding portion  101  that holds the bag  84  in a state where a portion of the bag  84  is expanded. The one of the gusset portions  97  of the bag  84  ( FIG. 8 ) is flattened by the clamping portion  99  of the clamping member  92 , and is sectioned into the two gusset portions  85  as shown in  FIG. 7 . The other one of the gusset portions  97  of the bag  84  ( FIG. 8 ) is expanded by the expansion holding portion  101 . 
     Accordingly, in the pack unit  81 , as shown in  FIG. 10  that is a cross-sectional view of the pack unit  81 , a communication portion  102  is formed in a portion below the center in the height direction along the Z axis of the ink container  78 . Thus, the first container  78 A and the second container  78 B are in communication with each other in the communication portion  102  formed in a portion below the center in the height direction along the Z axis of the ink container  78 . Accordingly, at the time of agitation, ink gathered on the lower side of the second container  78 B can be moved to the first container  78 A side such that the concentration of ink is made uniform. Note that the cross-sectional view shown in  FIG. 10  is equivalent to a cross-sectional view of the pack unit  81  when cut along the line A-A in  FIG. 7 . 
     With the above-described configuration, the first container  78 A and the second container  78 B are partitioned from each other at a portion clamped by the clamping portion  99  of the clamping member  92  as shown in  FIG. 7 , and are in communication with each other at a portion expanded by the expansion holding portion  101 . In other words, the ink container  78  is partitioned into the first container  78 A and the second container  78 B that are in communication with each other. 
     Note that, in place of the expansion holding portion  101 , a tubular member may be provided in the bag  84  so as to form a channel, an elastic member may be arranged in the bag  84  so as to expand the bag  84 , or the bag  84  may be molded through surface pressing (which will be described later in detail) so as to form a channel in the bag  84 , such that the first container  78 A and the second container  78 B of the bag  84  are in communication with each other. 
     In addition, as shown in  FIG. 7 , a rigidity member  103  is joined to a portion of the bag  84  overlapping the expansion holding portion  101  of the clamping member  92 . The rigidity member  103  is joined to a face  105 A and a face  105 B of the bag  84  as shown in  FIG. 8 . Examples of the rigidity member  103  include a sheet material made of PET (Polyethylene terephthalate). Portions of the face  105 A and the face  105 B of the bag  84  to which the rigidity member  103  is joined is unlikely to deform due to the rigidity of the rigidity member  103 . Therefore, as shown in  FIG. 7 , it is easy to maintain a state of expansion with the expansion holding portion  101 . In other words, it is easy to maintain communication between the first container  78 A and the second container  78 B. 
     As shown in  FIG. 5 , the air bag set  63  includes a first air bag  63 A and a second air bag  63 B. The first air bag  63 A and the second air bag  63 B have similar configurations. Therefore, the configuration of the first air bag  63 A will be described below in details, and a detailed description of the configuration of the second air bag  63 B will be omitted. Note that the same reference numerals as those of the first air bag  63 A are given to the constituent elements of the second air bag  63 B that are the same as those of the first air bag  63 A. Note that the first air bag  63 A corresponds to the air bag of the invention. 
     As shown in  FIG. 11 , the first air bag  63 A has a bag  111 , an introduction member  112 , and a tube  113 . The bag  111  is made of flexible film members, which are joined in a bag-like shape. In this embodiment, the bag  111  is formed by joining the film members through welding. The introduction member  112  is joined to the bag  111  at a joint portion  115  of the bag  111 . 
     As a mode of the bag  111 , various modes can be adopted such as a pillow-type bag, a standing pouch-type bag and a gusset-type bag. In this embodiment, a pillow-type bag is adopted as the bag  111 . The bag  111  has a configuration in which edges of two overlapped film materials are joined through welding. The joint portion  115  is provided at the peripheral edges of the pillow-type bag  111 . 
     The pillow-type bag  111  can be formed by joining the edges of two overlapped film materials through welding, for example. Here, the number of film materials is not limited to two. For example, the bag  111  in a bag-like shape can be formed by doubling over a single film material, and welding the overlapped end portions. In this case as well, the overlapping portion of the film material consists of two film materials. Therefore, even if the bag  111  is made of a single film material, there are two overlapping film materials. Thus, in both the case where the pillow-type bag  111  is made of a single film material, and the case where the pillow-type bag  111  is made of two or more film materials, the bag  111  has a configuration in which the edges of two overlapping film materials are joined through welding. 
     The introduction member  112  has a function as a connection portion that achieves connection between the bag  111  and the tube  113 . The introduction member  112  penetrates the joint portion  115 , and is inserted from outside the bag  111  into the bag  111 . The introduction member  112  and the bag  111  are joined to each other at the joint portion  115 . The introduction member  112  protrudes from inside the bag  111  to outside the bag  111 . In the following description, a section of the joint portion  115  intersecting the introduction member  112  is expressed as a joint portion  115 A when distinguished from the rest of the joint portion  115 . 
     As shown in  FIG. 12 , the introduction member  112  has an introduction port  116 . The introduction port  116  is an opening formed in the introduction member  112 . In a state where the introduction member  112  is joined to the bag  111 , the introduction port  116  is positioned outside the bag  111 . The introduction port  116  leads to the inside of the bag  111  via the introduction member  112 . Thus, the first air bag  63 A is configured such that the atmospheric air can be introduced from the introduction port  116  into the bag  111  via the introduction member  112 . The tube  113  is connected to a portion on the introduction port  116  side of the introduction member  112 . The atmospheric air can be introduced into the bag  111  via the tube  113  and the introduction member  112 . 
     The joint portion  115  that extends around the bag  111  along the peripheral edge of the bag  111  and a joint portion  117  that partitions, into two regions, the region around which the joint portion  115  extends are formed in the bag  111 . In the region around which the joint portion  115  extends, the joint portion  117  extends along the Y axis. The two regions partitioned by the joint portion  117  are called a first bag  118  and a second bag  119 . The first bag  118  and the second bag  119  are aligned along the Z axis. In the usage orientation, the second bag  119  is positioned above the first bag  118 . 
     The joint portion  117  extends in the −Y axis direction from a joint portion  1156  that is the opposite side to the joint portion  115 A of the joint portion  115  that extends along the peripheral edge of the bag  111 . The end portion on the +Y axis direction side of the joint portion  117  is connected to the joint portion  1156 . On the other hand, the end portion on the −Y axis direction side of the joint portion  117  is spaced apart from the joint portion  115 A. In other words, the joint portion  117  does not lead to the joint portion  115 A. Therefore, the first bag  118  and the second bag  119  partitioned by the joint portion  117  are in communication with each other. In the first air bag  63 A, the introduction port  116  is provided so as to be shared by the first bag  118  and the second bag  119 . In other words, the introduction port  116  of the introduction member  112  functions in common in the first bag  118  and the second bag  119 . Thus, atmospheric air that has been introduced from the introduction port  116  into the bag  111  via the introduction member  112  branches into the first bag  118  and the second bag  119 , in the bag  111 . 
     An introduction path  121  that branches into the first bag  118  and the second bag  119  from the introduction port  116  is formed in the bag  111 . Due to the introduction path  121 , the atmospheric air that has been introduced into the bag  111  via the introduction member  112  is likely to branch into the first bag  118  and the second bag  119 . The introduction path  121  is formed by performing surface press molding on at least one film material of the two film materials that make up the bag  111 . 
     The surface press molding is processing of partially performing stretch molding on a film material by pressing a portion of the film material using a molding mold toward the outside of the bag  111 . At this time, by heating the film material and the molding mold, the processing accuracy is improved and the processing time is shortened. By performing surface press molding, the introduction path  121  is formed in a direction so as to be recessed from inside of the bag  111  toward the outside of the bag  111 . By forming the introduction path  121  through surface press molding, a channel for atmospheric air can be secured as the introduction path  121  even in a state where the two film materials that make up the bag  111  adhere to each other, for example. 
     Note that as a method for forming the introduction path  121  other than surface press molding, a tubular member may be provided in the bag  84  so as to form a channel, an elastic member may be arranged in the bag  84  so as to expand the bag  84 , or the like. 
     When atmospheric air is introduced into the bag  111  via the tube  113  and the introduction member  112 , the first bag  118  and the second bag  119  are inflated, as shown in  FIG. 13 . Specifically, the first air bag  63 A includes the first bag  118  that can be inflated upon being supplied with atmospheric air that is an example of air and the second bag  119  that is positioned above the first bag  118  in the usage orientation, and can be inflated upon being supplied with atmospheric air. 
     Here, notch portions  125  are formed in the joint portion (bonded portion)  115  as shown in  FIG. 11 . The notch portions  125  are formed in portions adjacent to the first bag  118  in the direction along the Y axis and portions adjacent to the second bag  119  in the direction along the Y axis, in the joint portion  115 . In other words, the notch portions  125  are formed in portions adjacent to the first bag  118  and portions adjacent to the second bag  119 , in the joint portion  115 A and the joint portion  115 B. In this embodiment, the notch portions  125  are formed at two locations adjacent to the first bag  118 , respectively in the joint portion  115 A and the joint portion  115 B. The notch portions  125  are formed at two locations adjacent to the second bag  119 , respectively in the joint portion  115 A and the joint portion  115 B. Therefore, four notch portions  125  are formed in the first air bag  63 A. 
     The second air bag  63 B has a configuration similar to that of the first air bag  63 A, except that the length of the tube  113  is different. The first air bag  63 A having the above-described configuration and the second air bag  63 B are housed in the first case  61 , as shown in  FIG. 14 . Here, as shown in  FIG. 15 , a connection portion  127 , a connection portion  128 , and a connection portion  129  are provided in the first case  61 . The connection portion  127 , the connection portion  128 , and the connection portion  129  are provided in the second wall  72  of the first case  61 , and protrude from the second wall  72  in the Y axis direction. The connection portion  127  is in communication with the first air inlet port  51  ( FIG. 2 ). The connection portion  128  is in communication with the second air inlet port  52  ( FIG. 2 ). The connection portion  129  is in communication with the pressurization port  49  ( FIG. 2 ). 
     The tube  113  of the second air bag  63 B is connected to the connection portion  127 . As shown in  FIGS. 14 and 15 , the tube  113  of the first air bag  63 A is connected to the connection portion  128  positioned in the −X axis direction of the connection portion  129 . As shown in  FIG. 14 , the second air bag  63 B is housed in the first case  61  in a state where the tube  113  is connected to the connection portion  127 . Similarly, the first air bag  63 A is housed in the first case  61  in a state where the tube  113  is connected to the connection portion  128 . Therefore, the bag  111  of the second air bag  63 B is in communication with the first air inlet port  51  ( FIG. 2 ) via the introduction member  112 , the tube  113 , and the connection portion  127 . The bag  111  of the first air bag  63 A is in communication with the second air inlet port  52  ( FIG. 2 ) via the introduction member  112 , the tube  113 , and the connection portion  128 . 
     In this embodiment, when the first air bag  63 A and the second air bag  63 B are housed in the first case  61 , the tubes  113  of the first air bag  63 A and the second air bag  63 B are fixed to the first case  61 . In the first case  61 , claws  131  for holding the tubes  113  are provided along the arrangement path of the tubes  113 . When the first case  61  is seen in planar view in the −X axis direction, the tubes  113  are arranged in a region outside of the bags  111 . Therefore, when the first case  61  is seen in planar view in the −X axis direction, the tubes  113  do not overlap the bags  111 . Accordingly, it is easy to avoid the prevention of inflation of the bags  111  by the tubes  113 . 
     When atmospheric air is supplied to the first air inlet port  51  and the second air inlet port  52 , the first air bag  63 A and the second air bag  63 B are inflated as shown in  FIG. 16 . At this time, the dimensions along the Z axis of the bags  111  of the first air bag  63 A and the second air bag  63 B are reduced due to deformation caused by the inflation. In this embodiment, the first bags  118  of the first air bag  63 A and the second air bag  63 B are partially joined to the first wall  71  of the first case  61 . Therefore, when the first air bag  63 A and the second air bag  63 B are inflated, the height positions along the Z axis of the bags  111  are lowered relative to the first case  61 . 
     Note that when pillow-type bags  111  are inflated, the joint portion  115  formed through welding is likely to be resistant to inflation and deformation of the bags  111 , and thus the shape of the bags  111  when inflated is unlikely to be stabilized at a fixed shape. In this regard, in this embodiment, the notch portions  125  are formed in the joint portion  115 , and thus deformation of the joint portion  115  is likely to be concentrated on the notch portions  125  as shown in  FIG. 13 . Therefore, the shape of the pillow-type bags  111  when inflated is likely to be stabilized at a fixed shape. 
     When the pack assembly  64  is housed in the first case  61  after the first air bag  63 A and the second air bag  63 B are housed in the first case  61 , when the first case  61  is seen in planar view in the −X axis direction, the first air bag  63 A is arranged at a position overlapping the first container  78 A as shown in  FIG. 17 . Similarly, the second air bag  63 B is arranged at a position overlapping the second container  78 B. 
     In the usage orientation, when seen in planar view in the −X axis direction, the first bag  118  of the first air bag  63 A is arranged at a position overlapping a portion below the center in the Z axis direction in the ink container  78 . The first bag  118  of the second air bag  63 B is also arranged at a position overlapping a portion below a center  133  in the Z axis direction in the ink container  78 , when seen in planar view in the −X axis direction in the usage orientation. 
     Even when the first air bag  63 A and the second air bag  63 B are inflated, the first bags  118  of the first air bag  63 A and the second air bag  63 B are each positioned at a position overlapping a portion below the center  133  of the ink container  78  as shown in  FIG. 18 . At this time, as shown in  FIG. 19  that is a cross-sectional view of the cartridge  26  when cut along a line equivalent to a line B-B in  FIG. 18 , the first bag  118  comes into contact with the ink container  78 . In other words, the first air bag  63 A and the second air bag  63 B can come into contact with the ink container  78  in a state of being inflated upon receiving a supply of atmospheric air that is an example of air. At this time, a portion  134  at which the first bag  118  and the ink container  78  abut against each other is positioned below the center  133  of the ink container  78 . 
     In the usage orientation, a state where the first bag  118  overlaps a portion below the center  133  in the Z axis direction in the ink container  78  when seen in planar view in the −X axis direction means that the portion  134  at which the first bag  118  and the ink container  78  abut against each other is positioned below the center  133  of the ink container  78 . Therefore, as long as the abutting portion  134  is positioned below the center  133  of the ink container  78 , a configuration in which the first bag  118  projects upward of the center  133  of the ink container  78  is also included in the state where the first bag  118  overlaps a portion below the center  133  of the ink container  78 . 
     After the air bag set  63  and the pack assembly  64  are housed in the first case  61 , the first spacer  66  and the second spacer  68  are housed in the first case  61  as shown in  FIG. 20 . Here, a tube  137  is arranged in the first spacer  66 . One end  137 A of the tube  137  is open toward the inside of the first case  61 , in other words, toward an inner portion of the case  41 . The other end  137 B of the tube  137  is connected to the connection portion  129  as shown in  FIG. 21 . As described above, the connection portion  129  is in communication with the pressurization port  49 . 
     Atmospheric air supplied to the pressurization port  49  by the pump unit  29  is introduced from the connection portion  129  into the first case  61  via the tube  137  and the one end  137 A of the tube  137 . Accordingly, pressure is applied to the ink container  78 . The tube  137  connected to the connection portion  129  is open toward the inside of the first case  61 , at the one end  137 A positioned above the connection portion  129 . In this embodiment, when all of the ink in the ink container  78  has leaked out of the ink container  78 , the opening of the one end  137 A of the tube  137  is positioned higher than the liquid surface of the ink in the initial state when the cartridge  26  is mounted to the liquid jetting system  1 . Accordingly, it is possible to prevent ink that has leaked out of the ink container  78  from leaking to the outside from the case  41  via the pressurization port  49 . 
     In addition, by arranging an IC chip  138  above the pressurization port  49  in the Z axis direction, malfunctions, contact failures, and the like of the IC chip  138  can be prevented even if ink leaks out from the pressurization port  49  (see  FIG. 5 ). Note that information regarding ink and the like are recorded in the IC chip  138 . With the liquid jetting system  1 , when the cartridge  26  is mounted, or the like, it is possible to read information from the IC chip  138 , record new information or the like in the IC chip  138 , and the like. In other words, it is possible to exchange information between the liquid jetting system  1  and the IC chip  138 . 
     In this embodiment, as shown in  FIG. 20 , the tube  137  is buried in the first spacer  66 . Therefore, the tube  137  can be effectively arranged in the first case  61 , and thus the size of the cartridge  26  can be easily reduced. Note that a claw  139  that fixes the tube  137  is provided in the first spacer  66 . The tube  137  can be fixed using the claw  139 , and thus coming off of the tube  137  can be suppressed. 
     After the air bag set  63 , the pack assembly  64 , the first spacer  66 , and the second spacer  68  are housed in the first case  61 , the sheet member  69  is joined to the first case  61  as shown in  FIG. 22 . The sheet member  69  is provided in the X axis direction of the first case  61 . Accordingly, the airtightness of a region surrounded by the first case  61  and the sheet member  69  is improved. 
     When the cartridge  26  having the above-described configuration is mounted to the holder  27  ( FIG. 4 ), a hollow supply needle (not illustrated) provided in the holder  27  is fitted in the connection unit  93  of the pack assembly  64  ( FIG. 6 ). Accordingly, the valve inside the connection unit  93  is opened, and ink in the cartridge  26  is led out from the channel in the connection unit  93  to the ink supply tube  28  ( FIG. 4 ) via the supply needle. 
     In addition, when the cartridge  26  is mounted to the holder  27 , the pump unit  29  ( FIG. 4 ) is connected to the pressurization port  49 . The atmospheric air is then sent from the pump unit  29  into a space surrounded by the first case  61  and the sheet member  69 , in other words, the housing recess  76  ( FIG. 5 ). Accordingly, the bag  84  of the pack assembly  64  is pressurized in the cartridge  26 . As a result, ink in the bag  84  is sent into the printing head  19  via the ink supply tube  28  ( FIG. 4 ). 
     Incidentally, there are cases where a difference in the concentration of ink in the cartridge  26  occurs in the up-down direction due to gravity. For example, regarding pigment ink, there are cases where the pigment precipitates on the lower side of the bag  84  due to gravity. In such a case, there are cases where a difference in concentration occurs in the up-down direction. In this embodiment, ink in the bag  84  can be agitated by the air bag set  63 . 
     Note that the ink is not limited to being either pigment ink or dye ink. Also, pigment ink may have a configuration in which a dispersoid such as pigment is dispersed in a water-based dispersion medium, a configuration in which a dispersoid such as pigment is dispersed in an oil-based dispersion medium, and the like. Dye ink may have a configuration in which a solute such as dye is dissolved in a water-based solvent, a configuration in which a solute such as dye is dissolved in an oil-based solvent, and the like. 
     Examples of methods for agitating ink in the bag  84  using the air bag set  63  include a method of alternately inflating the first air bag  63 A and the second air bag  63 B. At this time, when inflating one of the first air bag  63 A and the second air bag  63 B, by opening the other to the atmospheric air, it is possible to avoid inflation of both the first air bag  63 A and the second air bag  63 B. 
     By alternately inflating the first air bag  63 A and the second air bag  63 B, it is possible to alternately press the first container  78 A and the second container  78 B. This makes it possible to allow ink to flow from the first container  78 A to the second container  78 B and ink to flow from the second container  78 B to the first container  78 A. Accordingly, it is possible to allow ink to flow between the first container  78 A and the second container  78 B. Thus, turbulence in the ink in the bag  84  occurs, and ink can be agitated effectively. As a result, the difference in concentration in the up-down direction can be effectively reduced. 
     As described above, in the first air bag  63 A and the second air bag  63 B, the first bag  118  is arranged at a position overlapping a portion below the center  133  in the Z axis direction of the ink container  78 . Therefore, when the air bag set  63  is inflated upon being supplied with atmospheric air, the first bag  118  can come into contact with the portion below the center  133  of the ink container  78 . Accordingly, the inflated air bag set  63  easily reaches a lower portion of the ink container  78 . Thus, with this cartridge  26 , the lower side of the ink container  78  is pressed efficiently, and the effect of agitating ink in the ink container  78  is easily improved. 
     Also, at this time, in the first air bag  63 A and the second air bag  63 B, the second bag  119  comes into contact with the ink container  78  above the first bag  118 . Accordingly, when a lower portion of the ink container  78  is pressed by the first bag  118 , it is easy to suppress movement of ink in the ink container  78  toward a position above the ink container  78 . As a result, it is possible to allow ink to effectively flow between the first container  78 A and the second container  78 B. Thus, a difference in the concentration in the up-down direction can be reduced more effectively. 
     In addition, in this embodiment, in the first air bag  63 A and the second air bag  63 B, the notch portions  125  are provided in the bag  111  as shown in  FIG. 16 . Accordingly, the shape of the pillow-type bag  111  when inflated is easily stabilized at a fixed shape. As a result, a stable agitation effect is likely to be acquired, and thus it is possible to easily improve the agitation effect further. 
     For example, if the shape of the bag  111  when inflated is not stable at a fixed shape, a mode in which the ink container  78  is pressed by the air bag set  63  is likely to change every time the ink container  78  is pressed, and thus a stable agitation effect is unlikely to be acquired. In this regard, with the cartridge  26  of this embodiment, by deforming the joint portion  115  centered on the notch portions  125  whose rigidity is lower than that of the periphery thereof, the shape of the pillow-type bag  111  when inflated is easily stabilized at a fixed shape. Thus, in this embodiment, a stable agitation effect is easily acquired. 
     Note that in this embodiment, the bag  84  is made of flexible film materials, and thus the entirety of the ink container  78  is flexible. However, a configuration may also be adopted in which only a portion of the ink container  78  that is pressed by the air bag set  63  is flexible. This is because the agitation effect as per the air bag set  63  is also acquired with this configuration. Therefore, it suffices for at least a portion of the ink container  78  to be flexible. Regarding the air bag set  63  as well, it suffices for at least a portion of the bag  111  to be flexible. 
     In this embodiment, a plurality of types of cartridges  26  in which the volume of the ink container  78  is different are set. For example, two types of cartridges  26  having different capacities can be set as the volumes of the ink containers  78 . The cartridge  26  in which the volume of the ink container  78  is larger is suitable for ink whose consumption amount is larger. On the other hand, compared to the cartridge  26  shown in  FIG. 5 , the cartridge  26  in which the volume of the ink container  78  is smaller is suitable for ink whose consumption amount is smaller as shown in  FIG. 23 . 
     Note that in the example of the ink container  78  shown in  FIG. 23 , the volume of the bag  84  is small compared to the ink container  78  shown in  FIG. 5 . Accordingly, in the example of the ink container  78  shown in  FIG. 23 , the volume of ink that can be contained is small compared to the ink container  78  shown in  FIG. 5 . For example, when the rate at which a printed article including many characters such as a document is printed is high, the consumption amount of black ink is relatively large compared to that of color ink. In such a case, it is conceivable that black ink is contained in the cartridge  26  in which the volume of the bag  84  is larger, and color ink is contained in the cartridge  26  in which the volume of the bag  84  is smaller. 
     In the ink pack  91  that contains color ink, one ink container  78  is provided for one bag  84 . Accordingly, in the ink pack  91  that contains color ink, the bag  84  is not partitioned into the first container  78 A and the second container  78 B. Therefore, two spacers  82  are applied to the ink pack  91  that contains color ink. 
     The invention is not limited to the above embodiments and working examples and can be achieved as various configurations without departing from the gist of the invention. For example, the technical features in the embodiments and the working examples that correspond to the technical features in the modes described in the summary of the invention can be replaced or combined as appropriate in order to solve a part of, or the entire foregoing problem, or to achieve some or all of the above-described effects. The technical features that are not described as essential in the specification may be deleted as appropriate.