Abstract:
A further improvement in convenience is desired in conventional liquid ejecting systems. A liquid supplying unit is mountable to a carriage that has a first projection, a second projection and a liquid introduction needle. The unit includes six wall portions. The first wall portion is provided with a liquid supplying portion connectable to a liquid introduction needle, a first recess portion adapted to receive the first projection, and a second recess portion adapted to receive the second projection. In a planar view of the first wall portion, the liquid supplying portion is positioned closer to the fifth wall portion than to the sixth wall portion, and when the first wall portion is equally divided into a first region, a second region and a third region, the first recess portion is positioned in the first region, and the second recess portion is positioned in the third region.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Japanese Application No. 2015-256065 filed on Dec. 28, 2015. The entire disclosure of this Japanese application is expressly incorporated by reference herein. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a liquid supplying unit, a liquid ejecting system and the like. 
         [0004]    2. Related Art 
         [0005]    Conventionally, as an example of a liquid ejecting apparatus, inkjet printers are known. In inkjet printers, ink, which is an example of a liquid, is discharged from an ejecting head onto a printing medium such as printing paper, thereby enabling printing onto the printing medium to be performed. In such inkjet printers, conventionally, a structure for supplying ink from an ink cartridge, which is an example of a liquid supplying unit, to the ejecting head is known (e.g., JP-A-2013-248779). Note that a structure in which the liquid supplying unit is mounted to the liquid ejecting apparatus will be referred to as a liquid ejecting system. 
         [0006]    JP-A-2013-248779 is an example of related art. 
       SUMMARY 
       [0007]    In the inkjet printer described in JP-A-2013-248779 above, the ink cartridge is mounted to a holder. This ink cartridge is provided with a lever that is engageable with the holder. In the state where the lever is engaged with the holder, the ink cartridge is mounted to the holder. In order to mount the ink cartridge to the holder, the user inserts the ink cartridge that he or she holds into the holder, and engages the lever with the holder. Thereby, the ink cartridge is mounted to the holder. At this time, the ink cartridge is manually mounted by the user. This is considered to be one of the factors that cause the entering orientation of the ink cartridge relative to the holder when the ink cartridge is inserted into the holder to vary easily. When the entering orientation of the ink cartridge comes out of an appropriate range, it is conceivable that the lever will not be properly engaged with the holder, and that the ink cartridge will be caught by the holder before the lever is engaged with the holder. If such a situation occurs, the convenience when mounting the ink cartridge to the holder deteriorates. Accordingly, in conventional liquid ejecting systems, further improvement in convenience is desired. 
         [0008]    The invention can solve at least the above-described issue, and can be realized as the following aspects or application examples. 
       Application Example 1 
       [0009]    A liquid supplying unit that is mountable to a carriage having a first projection, a second projection and a liquid introduction needle positioned between the first projection and the second projection includes: a first wall portion; a second wall portion opposing the first wall portion; a third wall portion intersecting the first wall portion and the second wall portion; a fourth wall portion intersecting the first wall portion and the second wall portion, and opposing the third wall portion; a fifth wall portion intersecting the first wall portion, the second wall portion, the third wall portion and the fourth wall portion; and a sixth wall portion intersecting the first wall portion, the second wall portion, the third wall portion and the fourth wall portion, and opposing the fifth wall portion, wherein the first wall portion is provided with a liquid supplying portion connectable to the liquid introduction needle, a first recess portion adapted to receive the first projection, and a second recess portion adapted to receive the second projection, and in a planar view of the first wall portion in a direction from the first wall portion toward the second wall portion: the liquid supplying portion is positioned closer to the fifth wall portion than to the sixth wall portion; and when the first wall portion is equally divided into a first region, a second region and a third region in a direction from the fifth wall portion toward the sixth wall portion, the first recess portion is positioned in the first region, and the second recess portion is positioned in the third region. 
         [0010]    In this liquid supplying unit, the first projection can be inserted into the first recess portion, and the second projection can be inserted into the second recess portion. Therefore, when mounting the liquid supplying unit to the carriage, the first recess portion and the second recess portion can be used as guides for the mounting. It is possible to reduce variation in the orientation of the liquid supplying unit relative to the carriage when mounting the liquid supplying unit to the carriage. As a result, it is easy to improve the convenience when mounting the liquid supplying unit to the carriage. 
       Application Example 2 
       [0011]    In the above-described liquid supplying unit, the first wall portion may be provided with a detection target unit in which a liquid residual quantity is detected, and in a planar view of the first wall portion in the direction from the first wall portion toward the second wall portion: the liquid supplying portion may be positioned closer to the fifth wall portion than to the sixth wall portion; the first recess portion may be positioned closer to the fifth wall portion than the liquid supplying portion; the second recess portion may be positioned closer to the sixth wall portion than the liquid supplying portion; and the detection target unit may be positioned between the first recess portion and the second recess portion in a direction from the fifth wall portion toward the sixth wall portion. 
         [0012]    According to such a configuration, the first projection can be inserted into the first recess portion, and the second projection can be inserted into the second recess portion. Therefore, when mounting the liquid supplying unit to the carriage, the position of the first recess portion can be regulated by the first projection, and the position of the second recess portion can be regulated by the second projection. As a result, it is possible to reduce variation in the orientation of the liquid supplying unit relative to the carriage after the liquid supplying unit is mounted to the carriage. As a result, it is easy to suppress deterioration in the detection accuracy in the detection target unit. 
       Application Example 3 
       [0013]    The above-described liquid supplying unit may further include a contact portion that is arranged on the fifth wall portion, and that comes into contact with an electrode of the carriage in a state where the liquid supplying unit is mounted to the carriage, wherein in a planar view of the first wall portion in the direction from the first wall portion toward the second wall portion, a portion of the liquid supplying portion capable of abutting on the liquid introduction needle, the contact portion, the first recess portion and the second recess portion may be arranged along a straight line. 
         [0014]    According to such a configuration, the portion of the liquid supplying portion capable of abutting on the liquid introduction needle, the contact portion, the first recess portion and the second recess portion are each one of the factors that regulate the position of the liquid supplying unit relative to the carriage when the liquid supplying unit is mounted to the carriage. By aligning the factors that regulate the position of the liquid supplying unit relative to the carriage along a straight line, it is possible to improve a function of guiding the liquid supplying unit to the carriage when mounting the liquid supplying unit to the carriage. 
       Application Example 4 
       [0015]    In the above-described liquid supplying unit, the fifth wall portion may be provided with an engagement structure configured to engage with the carriage in a state where the liquid supplying unit is mounted to the carriage, so as to regulate displacement of the liquid supplying unit relative to the carriage in a first direction from the first wall portion toward the second wall portion, and in a planar view of the first wall portion in the direction from the first wall portion toward the second wall portion: a portion of the engagement structure capable of abutting on the carriage, the portion of the liquid supplying portion capable of abutting on the liquid introduction needle, the first recess portion and the second recess portion may be arranged along a straight line. 
         [0016]    According to such a configuration, the portion of the engagement structure capable of abutting on the carriage, the portion of the liquid supplying portion capable of abutting on the liquid introduction needle, the first recess portion and the second recess portion are each one of the factors that regulate the position of the liquid supplying unit relative to the carriage when the liquid supplying unit is mounted to the carriage. By aligning the factors that regulate the position of the liquid supplying unit relative to the carriage along a straight line, it is possible to improve a function of guiding the liquid supplying unit relative to the carriage when mounting the liquid supplying unit to the carriage. 
       Application Example 5 
       [0017]    In the above-described liquid supplying unit, the first recess portion may be open in a direction from the second wall portion toward the first wall portion and in a direction from the third wall portion toward the fourth wall portion. 
         [0018]    According to such a configuration, the first recess portion is open in two directions, and thus it is possible to easily insert the first projection into the first recess portion. Accordingly, the liquid supplying unit can be easily mounted to the carriage. 
       Application Example 6 
       [0019]    In the above-described liquid supplying unit, the second recess portion may be open in a direction from the second wall portion toward the first wall portion and in a direction from the third wall portion toward the fourth wall portion. 
         [0020]    According to such a configuration, the second recess portion is open in two directions, and thus it is possible to easily insert the second projection into the second recess portion. Accordingly, the liquid supplying unit can be easily mounted to the carriage. 
       Application Example 7 
       [0021]    In a liquid ejecting system including an carriage and a liquid supplying unit that is mounted to the carriage and that is capable of containing a liquid, the carriage includes: a first projection; a second projection; and a liquid introduction needle positioned between the first projection and the second projection, the liquid supplying unit includes: a first wall portion; a second wall portion opposing the first wall portion; a third wall portion intersecting the first wall portion and the second wall portion; a fourth wall portion intersecting the first wall portion and the second wall portion, and opposing the third wall portion; a fifth wall portion intersecting the first wall portion, the second wall portion, the third wall portion and the fourth wall portion; and a sixth wall portion intersecting the first wall portion, the second wall portion, the third wall portion and the fourth wall portion, and opposing the fifth wall portion, the first wall portion is provided with a liquid supplying portion connectable to the liquid introduction needle, a first recess portion adapted to receive the first projection, and a second recess portion adapted to receive the second projection, in a planar view of the first wall portion in a first direction from the first wall portion toward the second wall portion: the liquid supplying portion is positioned between the fifth wall portion and the sixth wall portion; the first recess portion is positioned between the fifth wall portion and the liquid supplying portion; and the second recess portion is positioned between the sixth wall portion and the liquid supplying portion, assuming a direction from the second wall portion toward the first wall portion to be a second direction, the liquid supplying portion protrudes from the first wall portion in the second direction, the liquid supplying portion protrudes farther than a portion of the first wall portion in which the first recess portion is provided, by a first distance in the second direction, the first projection protrudes farther than the liquid introduction needle by a second distance in the first direction, and the second distance is greater than the first distance. 
         [0022]    In this liquid ejecting system, when the liquid supplying unit is mounted to the carriage, the first projection is likely to enter the first recess portion before the liquid introduction needle enters the liquid supplying portion. Accordingly, when the liquid supplying unit is mounted to the carriage, the first recess portion is guided to the first projection, and thereby the liquid supplying portion is easily guided toward the liquid introduction needle. As a result, it is easy to stabilize the orientation of the liquid supplying unit relative to the carriage when the liquid introduction needle enters the liquid supplying portion. 
       Application Example 8 
       [0023]    In the above-described liquid ejecting system, the second projection may protrude farther than the liquid introduction needle by a third distance in the first direction, and the third distance may be greater than the first distance. 
         [0024]    According to such a configuration, when the liquid supplying unit is mounted to the carriage, it is likely that the first projection enters the first recess portion, and the second projection enters the second recess portion before the liquid introduction needle enters the liquid supplying portion. Accordingly, when the liquid supplying unit is mounted to the carriage, the first recess portion is guided to the first projection, and the second recess portion is guided to the second projection, and thereby the liquid supplying portion is easily guided toward the liquid introduction needle. As a result, it becomes easier to further stabilize the orientation of the liquid supplying unit relative to the carriage when the liquid introduction needle enters the liquid supplying portion. 
       Application Example 9 
       [0025]    In the above-described liquid ejecting system, the liquid supplying unit may further include a contact portion that is arranged on the fifth wall portion, and that comes into contact with an electrode of the carriage, and the second distance may be greater than the third distance. 
         [0026]    According to such a configuration, when the liquid supplying unit is mounted to the carriage, the first projection is likely to enter the first recess portion before the second projection enters the second recess portion. Therefore, when the liquid supplying unit is mounted to the carriage, the first recess portion is likely to be guided to the first projection before the second recess portion is guided to the second projection. Accordingly, the first recess portion is likely to be guided before the second recess portion. Also, the contact portion of the liquid supplying unit is provided on the fifth wall portion that is closer to the first recess portion than to second recess portion. In other words, the contact portion is closer to the first recess portion that is likely to be guided before the second recess portion. Therefore, when the liquid supplying unit is mounted to the carriage, the contact portion that is close to the first recess portion is likely to be guided at an early stage, and thus it is easy to stabilize the orientation of the liquid supplying unit relative to the carriage when the contact portion comes into contact with the electrode. As a result, when the liquid supplying unit is mounted to the carriage, the contact portion is easily brought into contact with the electrode in a stable manner. 
       Application Example 10 
       [0027]    In the above-described liquid ejecting system, the first recess portion and the contact portion may be provided at positions opposing each other such that the fifth wall portion is positioned therebetween. 
         [0028]    According to such a configuration, the first recess portion and the contact portion are provided at positions opposing each other such that the fifth wall portion is positioned therebetween, and thus in a state where the liquid supplying unit is mounted to the carriage, a position relationship is obtained in which the contact portion is positioned between the electrode of the carriage and the first projection. Therefore, the contact portion is easily brought into contact with the electrode. 
       Application Example 11 
       [0029]    The above-described liquid ejecting system may include a detecting unit configured to detect a residual quantity of the liquid contained in the liquid supplying unit, wherein the liquid supplying unit may have, in the first wall portion, a detection target unit in which the residual quantity of the liquid is detected by the detecting unit, and in a planar view of the first wall portion in a direction from the first wall portion toward the second wall portion: the liquid supplying portion may be positioned closer to the fifth wall portion than to the sixth wall portion; the first recess portion may be positioned closer to the fifth wall portion than the liquid supplying portion; the second recess portion may be positioned closer to the sixth wall portion than the liquid supplying portion; and the detection target unit may be positioned between the first recess portion and the second recess portion in a direction from the fifth wall portion toward the sixth wall portion. 
         [0030]    According to such a configuration, when mounting the liquid supplying unit to the carriage, the position of the first recess portion can be regulated by the first projection, and the position of the second recess portion can be regulated by the second projection. As a result, it is possible to reduce variation in the orientation of the liquid supplying unit relative to the carriage after the liquid supplying unit is mounted to the carriage. As a result, it is easy to suppress deterioration in detection accuracy when detecting the residual quantity of the liquid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
           [0032]      FIG. 1  is a perspective view schematically showing a main configuration of a liquid ejecting system in a first embodiment. 
           [0033]      FIG. 2  is a perspective view showing a holder in the first embodiment. 
           [0034]      FIG. 3  is a perspective view showing the holder in the first embodiment. 
           [0035]      FIG. 4  is a diagram showing the appearance of a cartridge in the first embodiment. 
           [0036]      FIG. 5  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0037]      FIG. 6  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0038]      FIG. 7  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0039]      FIG. 8  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0040]      FIG. 9  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0041]      FIG. 10  is a perspective view showing the appearance of the cartridge in the first embodiment. 
           [0042]      FIG. 11  is a diagram showing the appearance of a circuit substrate in the first embodiment. 
           [0043]      FIG. 12  is a cross-sectional view showing a liquid supplying portion in the first embodiment. 
           [0044]      FIG. 13  is a cross-sectional view showing the liquid supplying portion in the first embodiment. 
           [0045]      FIG. 14  is a perspective view showing the appearance of the cartridge in the first embodiment. 
           [0046]      FIG. 15  is a cross-sectional view showing the cartridge in the first embodiment. 
           [0047]      FIG. 16  is a cross-sectional view showing the cartridge and the holder in the first embodiment. 
           [0048]      FIG. 17  is a diagram showing the appearance of the cartridge in the first embodiment. 
           [0049]      FIG. 18  is a cross-sectional view showing the holder in the first embodiment. 
           [0050]      FIG. 19  is a cross-sectional view showing the cartridge and the holder in the first embodiment. 
           [0051]      FIG. 20  is a cross-sectional view showing the cartridge and the holder in the first embodiment. 
           [0052]      FIG. 21  is a perspective view schematically showing a main configuration of a liquid ejecting system in a second embodiment. 
           [0053]      FIG. 22  is a cross-sectional view showing a cartridge and a holder in the second embodiment. 
           [0054]      FIG. 23  is a cross-sectional view schematically showing a detecting unit and a detection target unit in the second embodiment. 
           [0055]      FIG. 24  is a diagram showing the appearance of the cartridge in the second embodiment. 
           [0056]      FIG. 25  is a diagram showing the appearance of a cartridge in a third embodiment. 
           [0057]      FIG. 26  is a diagram showing the appearance of the cartridge in the third embodiment. 
           [0058]      FIG. 27  is a diagram showing the appearance of the cartridge in the third embodiment. 
           [0059]      FIG. 28  is a diagram showing the appearance of the cartridge in the third embodiment. 
           [0060]      FIG. 29  is a diagram showing the appearance of the cartridge in the third embodiment. 
           [0061]      FIG. 30  is a diagram showing the appearance of the cartridge in the third embodiment. 
           [0062]      FIG. 31  is a perspective view showing the appearance of the cartridge in the third embodiment. 
           [0063]      FIG. 32  is a diagram illustrating a schematic configuration of a liquid supplying unit in Modified Example 1. 
           [0064]      FIG. 33  is a diagram showing the appearance of a cartridge in Modified Example 2. 
           [0065]      FIG. 34  is a diagram showing the appearance of a cartridge in Modified Example 3. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0066]    Embodiments of the invention will be described with reference to the drawings by way of example of a liquid ejecting system that includes an inkjet printer (hereinafter, referred to as a printer) serving as an example of a liquid ejecting apparatus. Note that in the drawings, the scales of constituent elements and members may be different in order to have such sizes that allow the constituent elements to be identifiable. 
       First Embodiment 
       [0067]    A liquid ejecting system  1  in this embodiment has a printer  5  that is an example of a liquid ejecting apparatus, and a cartridge  7  that is an example of a liquid supplying unit, as shown in  FIG. 1 . The cartridge  7  can contain ink, which is an example of a liquid. The liquid ejecting system  1  has a plurality of (two or more) cartridges  7 . Note that in this embodiment, the printer  5  is equipped with four cartridges  7 . The liquid ejecting system  1  can perform printing onto a recording medium P such as recording paper using ink that is an example of liquid. Note that the number of cartridges  7  that can be mounted to the printer  5  is not limited to four, and any suitable number that is one or more can be adopted. 
         [0068]    Here, the liquid ejecting system is an apparatus that includes the liquid ejecting apparatus and the liquid supplying unit. The term “liquid ejecting system” is applied in order to clearly distinguish between a liquid ejecting apparatus equipped with a liquid supplying unit and a liquid ejecting apparatus that does not include a liquid supplying unit. Accordingly, an apparatus obtained by removing a liquid supplying unit from a liquid ejecting system is a liquid ejecting apparatus. However, the expression “liquid ejecting apparatus” does not clearly distinguish between the liquid ejecting apparatus equipped with the liquid supplying unit and the liquid ejecting apparatus that does not includes the liquid supplying unit. Accordingly, the concept of the liquid ejecting apparatus encompasses the liquid ejecting apparatus equipped with the liquid supplying unit and the liquid ejecting apparatus that does not have the liquid supplying unit, and this expression can be applied to both. 
         [0069]    However, in the present specification, unless particularly stated otherwise, the liquid ejecting apparatus refers to a liquid ejecting apparatus that does not include a liquid supplying unit. Also, in the present specification, the concept of the liquid ejecting system encompass a liquid ejecting apparatus and a liquid supplying unit, and is not applied to a liquid ejecting apparatus that does not include a liquid supplying unit. Note that above-described definition does not deny that both the expression “liquid ejecting system” and the expression “liquid ejecting apparatus equipped with a liquid supplying unit” are used without distinguishing therebetween. Therefore, in the following description, both the expression “liquid ejecting apparatus equipped with a liquid supplying unit” and “liquid ejecting system” may be used without distinguishing therebetween. 
         [0070]    According to the above-described definition, the liquid ejecting system  1  in this embodiment is the printer  5  equipped with the cartridge  7 . Also, the printer  5  corresponds to an apparatus obtained by removing the cartridge  7  from the liquid ejecting system  1 . In  FIG. 1 , X, Y and Z axes, which are coordinate axes orthogonal to each other, are added. In the figures shown hereinafter, X, Y and Z axes are given as necessary. In this case, the X, Y and Z axes in each figure correspond to the X, Y and Z axes in  FIG. 1 .  FIG. 1  illustrates a state where the liquid ejecting 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 ejecting system  1  is arranged on the XY plane that matches the horizontal plane is a usage state of the liquid ejecting system  1 . The orientation of the liquid ejecting system  1  when the liquid ejecting system  1  is arranged on the XY plane matching the horizontal plane is referred to as a usage orientation of the liquid ejecting system  1 . 
         [0071]    In the following description, the X axis, the Y axis, and the Z axis that are added in figures and description illustrating the constituent elements and units of the liquid ejecting system  1  refer to the X axis, the Y axis, and the Z axis in a state where the constituent elements and units are incorporated (mounted) in the liquid ejecting system  1 . Also, the orientation of each constituent element or unit in the usage orientation of the liquid ejecting system  1  is referred to as a usage orientation of the constituent element or unit. In addition, in the following description, description of the liquid ejecting system  1 , the constituent elements and units thereof and the like is description in the usage orientation of the liquid ejecting system  1 , the constituent elements and units thereof and the like, unless particularly stated otherwise. 
         [0072]    The Z axis is an axis orthogonal to the XY plane. In the usage state of the liquid ejecting system  1 , the Z axis direction is upward in the vertical direction. In the usage state of the liquid ejecting system  1 , in  FIG. 1 , the −Z axis direction is downward in the vertical direction. Note that regarding each of the X, Y and Z axes, the direction of the arrow indicates a + (positive) direction, and the direction opposite to the direction of the arrow indicates a − (negative) direction. Note that the above-described four cartridges  7  are aligned along the X axis. Therefore, the X axis direction can also be defined as the direction in which the four cartridges  7  are aligned. 
         [0073]    The printer  5  has a carriage  9 , a recording head  11  and a holder  12 . The carriage  9  is configured to be able to reciprocally move along the X axis. The carriage  9  is equipped with the recording head  11  and the holder  12 . The recording head  11 , which is an example of a liquid ejecting head, is positioned on the −Z axis direction side of the carriage  9 . The holder  12  is positioned on the Z axis direction side of the carriage  9 . The holder  12  is configured such that a plurality of cartridges  7  can be mounted thereto. The cartridges  7  are removably mounted to the holder  12 . The carriage  9  is connected to a timing belt  13 . Motive power from a motor  14  is transmitted to the carriage  9  via the timing belt  13 . Accordingly, the carriage  9  can reciprocally move along the X axis. 
         [0074]    Moreover, in the printer  5 , motive power from a conveyance motor (not illustrated) is transmitted to a conveyance roller  15 . The conveyance roller  15  extends along the X axis. In the printer  5 , by rotating the conveyance roller  15  using the motive power from the conveyance motor, the recording medium P can be conveyed in the Y axis direction. 
         [0075]    Ink in the cartridge  7  mounted to the holder  12  is supplied to the recording head  11 . A nozzle opening (not illustrated) that is open toward the recording medium P side is formed on the recording head  11 . The ink supplied from the cartridges  7  to the recording head  11  is discharged as ink droplets from the nozzle opening of the recording head  11  toward the recording medium P. 
         [0076]    The printer  5  is further provided with a control unit  16  for controlling the above-described mechanisms. The recording head  11  is connected to the control unit  16  via a flexible cable  17 . In the liquid ejecting system  1  configured as described above, recording is performed onto the recording medium P by causing the recording head  11  to discharge ink droplets at a predetermined position while conveying the recording medium P in the Y axis direction and reciprocally moving the carriage  9  along the X axis. 
         [0077]    Here, a direction along the X axis is not limited to a direction perfectly parallel to the X axis, and includes directions inclined due to error, tolerance and the like, except for the direction orthogonal to the X axis. Similarly, a direction along the Y axis is not limited to a direction perfectly parallel to the Y axis, and includes directions inclined due to error, tolerance and the like, except for the direction orthogonal to the Y axis. A direction along the Z axis is not limited to a direction perfectly parallel to the Z axis, and includes directions inclined due to error, tolerance and the like, except for the direction orthogonal to the Z axis. Accordingly, a direction along any axis and plane is not limited to a direction perfectly parallel to that axis and plane, and includes directions inclined due to error, tolerance and the like, except for the direction orthogonal to the axis and plane. 
         [0078]    The holder  12  has a recess portion  21  as shown in  FIG. 2 . The cartridges  7  are mounted in the recess portion  21  of the holder  12 . In this embodiment, four cartridges  7  can be housed in the recess portion  21 . In this embodiment, the four cartridges  7  mounted in the recess portion  21  are housed with gaps therebetween in the recess portion  21 . In the recess portion  21 , mounting positions respectively corresponding to the four cartridges  7  that are mounted in the recess portion  21  are specified. The four mounting positions are aligned along the X axis in the recess portion  21 . Accordingly, the four cartridges  7  are housed in the recess portion  21  in a state of being aligned along the X axis. 
         [0079]    Four ink introduction needles  23  are provided on a bottom portion  22  in the recess portion  21 . The ink introduction needle  23  is an example of a liquid introduction needle. The number of ink introduction needles  23  provided in the recess portion  21  is the same as the number of cartridges  7  that can be mounted to the holder  12 . The four ink introduction needles  23  protrude from the bottom portion  22  in the Z axis direction. The four ink introduction needles  23  are aligned along the X axis. Ink contained in the cartridges  7  is supplied from the ink introduction needles  23  to the printer  5 . Specifically, the ink contained in the cartridges  7  is supplied to the recording head  11  ( FIG. 1 ) via the ink introduction needles  23 . 
         [0080]    The holder  12  has a side wall  25 , a side wall  26 , a side wall  27  and a side wall  28 . The side wall  25 , the side wall  26 , the side wall  27  and the side wall  28  each intersect the bottom portion  22  and protrude from the bottom portion  22  in the Z axis direction. 
         [0081]    The side wall  25  and the side wall  26  oppose each other along the Y axis such that the ink introduction needle  23  is positioned therebetween. The side wall  25  is positioned in the −Y axis direction relative to the ink introduction needle  23 . Also, the side wall  26  is positioned in the Y axis direction relative to the ink introduction needle  23 . The side wall  27  and the side wall  28  oppose each other along the X axis such that the ink introduction needle  23  is positioned therebetween. The side wall  27  is positioned in the −X axis direction relative to the ink introduction needle  23 . Also, the side wall  28  is positioned in the X axis direction relative to the ink introduction needle  23 . The bottom portion  22  is surrounded by the side wall  25 , the side wall  26 , the side wall  27  and the side wall  28 . The recess portion  21  is defined in this manner. 
         [0082]    Note that the bottom portion  22  and the side walls  25  to  28  are not limited to a flat wall, and may include recessions and protrusions, or may include a curved surface. Also, the side walls  25  to  28  do not need to be orthogonal to the bottom portion  22 , and it suffices for those side walls to intersect the bottom portion  22 . Moreover, two surfaces intersecting each other indicates a positional relationship in which the two surfaces are not parallel to each other. In addition to a case where two surfaces are in direct contact with each other, a positional relationship in which two surfaces are not in direct contact and are separated, and a relationship in which an extension of one surface and an extension of the other surface intersect each other are also expressed as “intersecting”. The angle formed by two intersecting surfaces may be any of a right angle, an obtuse angle, and an acute angle. 
         [0083]    The holder  12  has first projections  31 , second projections  32 , engaging portions  33  and contact mechanisms  34  as shown in  FIG. 3 . In order to clearly illustrate the configuration,  FIG. 3  shows a state where a portion of the holder  12  is cut away. The first projections  31 , the second projections  32 , the engaging portions  33  and the contact mechanisms  34  are provided respectively in correspondence with the cartridges  7  that can be mounted to the holder  12 . Specifically, in this embodiment, the holder  12  has four first projections  31 , four second projections  32 , four engaging portions  33  and four contact mechanisms  34 . The four first projections  31  are aligned along the X axis. The four second projections  32  are aligned along the X axis. The four engaging portions  33  are aligned along the X axis. The four contact mechanisms  34  are aligned along the X axis. 
         [0084]    The first projections  31  and the second projections  32  each protrude from the bottom portion  22  in the Z axis direction. The first projections  31  and the second projections  32  each protrude farther than the ink introduction needles  23  in the Z axis direction. In a planar view of the holder  12  in the −Z axis direction, the first projections  31  are positioned in the −Y axis direction relative to the ink introduction needles  23 , and are positioned in the Y axis direction relative to the side wall  25 . In a planar view of the holder  12  in the −Z axis direction, the second projections  32  are positioned in the Y axis direction relative to the ink introduction needles  23 , and are positioned in the −Y axis direction relative to the side wall  26 . 
         [0085]    The engaging portions  33  are provided in the side wall  25 . The engaging portions  33  are provided at the end portion in the Z axis direction of the side wall  25 . The engaging portions  33  protrude from the side wall  25  in the Y axis direction. The engaging portions  33  are configured to be engageable with engagement portions (to be described later) of the cartridges  7 . The engagement portions of the cartridges  7  engage with the engaging portions  33  of the holder  12 , and thereby the cartridges  7  are mounted to the holder  12 . 
         [0086]    The side wall  25  is provided with the contact mechanisms  34 . In the side wall  25 , the contact mechanisms  34  are positioned between the bottom portion  22  and the engaging portions  33 . Each contact mechanism  34  has a plurality of electrode pins  35 . The electrode pin  35  is an example of an electrode. The contact mechanism  34  constitutes a connection portion that is electrically connectable to a circuit substrate (to be described later) of the cartridge  7 . The circuit substrate of the cartridge  7  can be electrically connected to the control unit  16  of the printer  5  via the contact mechanism  34 . 
         [0087]    The cartridge  7  will be described. The cartridge  7  has a first wall portion  41 , as shown in  FIG. 4 .  FIG. 4  illustrates a state where the cartridge  7  is seen in a planar view in the Z axis direction. The cartridge  7  also has a second wall portion  42  as shown in  FIG. 5 .  FIG. 5  illustrates a state where the cartridge  7  is seen in a planar view in the −Z axis direction. Also, the cartridge  7  has a third wall portion  43  as shown in  FIG. 6 .  FIG. 6  illustrates a state where the cartridge  7  is seen in a planar view in the X axis direction. 
         [0088]    The cartridge  7  also has a fourth wall portion  44  as shown in  FIG. 7 .  FIG. 7  illustrates a state where the cartridge  7  is seen in a planar view in the −X axis direction. The cartridge  7  also has a fifth wall portion  45  as shown in  FIG. 8 .  FIG. 8  illustrates a state where the cartridge  7  is seen in a planar view in the Y axis direction. The cartridge  7  also has a sixth wall portion  46  as shown in  FIG. 9 .  FIG. 9  illustrates a state where the cartridge  7  is seen in a planar view in the −Y axis direction. Note that the first to sixth wall portions  41  to  46  are not limited to a flat wall, and may include recessions and protrusions, or may include a curved surface. 
         [0089]    The first wall portion  41  and the second wall portion  42  each intersect the Z axis. The first wall portion  41  and the second wall portion  42  oppose each other. The second wall portion  42  is positioned in the Z axis direction relative to the first wall portion  41 . The third wall portion  43  and the fourth wall portion  44  each intersect the X axis. The third wall portion  43  and the fourth wall portion  44  oppose each other. The fourth wall portion  44  is positioned in the X axis direction relative to the third wall portion  43 . 
         [0090]    The fifth wall portion  45  and the sixth wall portion  46  each intersect the Y axis. The fifth wall portion  45  and the sixth wall portion  46  oppose each other. The sixth wall portion  46  is positioned in the Y axis direction relative to the fifth wall portion  45 . The first wall portion  41  and the second wall portion  42  each intersect the third wall portion  43  to the sixth wall portion  46 . The third wall portion  43  and the fourth wall portion  44  each intersect the fifth wall portion  45  and the sixth wall portion  46 . 
         [0091]    A liquid container  47  shown in  FIG. 6  is formed in the region surrounded by the first to sixth wall portions  41  to  46  of the cartridge  7 . In the cartridge  7 , ink is contained in the liquid container  47 . Accordingly, in the cartridge  7 , ink is contained in the region surrounded the first to sixth wall portions  41  to  46 . 
         [0092]    As shown in  FIG. 10 , a liquid supplying portion  51  is provided in the first wall portion  41 . The ink in the liquid container  47  of the cartridge  7  is supplied to the ink introduction needle  23  ( FIG. 3 ) of the holder  12  via the liquid supplying portion  51 . In addition, a lever  52  and a circuit substrate  53  are provided on the fifth wall portion  45 . The lever  52  protrudes from the fifth wall portion  45  in the −Y axis direction, and extends in the Z axis direction. 
         [0093]    The lever  52  is provided with the above-described engagement portion  54 . The engagement portion  54  is formed on a portion of the lever  52  that faces the side opposite to the fifth wall portion  45  side, and protrudes in the direction opposite to the fifth wall portion  45  side. The end portion on the Z axis direction side of the engagement portion  54  engages with the end portion in the −Z axis direction of the engaging portion  33  ( FIG. 3 ) of the holder  12 , and thereby the cartridge  7  is mounted to the holder  12 . Accordingly, the end portion on the Z axis direction side of the engagement portion  54  engages with the end portion on the −Z axis direction side of the engaging portion  33 , thereby enabling the displacement of the cartridge  7  relative to the carriage  9  to be regulated. Note that the lever  52  is an example of an engagement structure, and the engagement portion  54  is an example of a portion that can abut on the carriage  9 . 
         [0094]    The circuit substrate  53  has a terminal portion  56  as shown in  FIG. 11 . The circuit substrate  53  has a plurality of terminals  57 . The terminals  57  have contact portions  58  that can be in electric contact with the electrode pins  35  of the contact mechanism  34 . The terminal portion  56  refers to the function structure that includes a plurality of contact portions  58  that can be in electric contact with the electrode pins  35  of the contact mechanism  34 . The terminal portion  56  may be provided on the substrate. In this embodiment, at least some of the plurality of terminals  57  are connected to a storage apparatus (not illustrated) provided on the circuit substrate  53 . Moreover, as an example of the plurality of terminals  57 , in this embodiment, a configuration is adopted in which a plurality of metal pads are aligned as the terminals  57  on the circuit substrate  53 . Also, in a state where the cartridge  7  is mounted to the holder  12 , the storage apparatus provided on the circuit substrate  53  of the cartridge  7  and the control unit  16  ( FIG. 1 ) of the printer  5  are electrically connected to each other via the contact mechanism  34 . Accordingly, various types of information are exchanged between the storage apparatus provided on the circuit substrate  53  of the cartridge  7  and the control unit  16  of the printer  5 . 
         [0095]    The liquid supplying portion  51  has a sealing member  61 , a valve body  62  and a spring  63  as shown in  FIG. 12 . A case  64  that constitutes the shell of the cartridge  7  has a supply port  65  formed therein. The supply port  65  is formed in the first wall portion  41 . The supply port  65  leads to the liquid container  47  through the first wall portion  41 . The sealing member  61 , the valve body  62  and the spring  63  are housed in the supply port  65 . Note that  FIG. 12  shows a cross section of the liquid supplying portion  51  that is cut along the YZ plane. 
         [0096]    The spring  63 , the valve body  62  and the sealing member  61  are housed in the supply port  65  in this order in a direction from the supply port  65  toward the inside of the liquid container  47 . The spring  63  is positioned on the liquid container  47  side relative to the valve body  62 . The valve body  62  is positioned on the liquid container  47  side relative to the sealing member  61 . The spring  63  is positioned between a spring fixing portion  66  and the valve body  62 . The valve body  62  is positioned between the spring  63  and the sealing member  61 . Therefore, the valve body  62  is biased by the spring  63  toward the sealing member  61  side. 
         [0097]    The sealing member  61  is constituted by an elastic body made of rubber, an elastomer or the like. The sealing member  61  is press-fitted in the supply port  65 . The sealing member  61  is provided with a through hole  67 . The internal diameter of the through hole  67  is smaller than the external diameter of the ink introduction needle  23 . 
         [0098]    In a state of overlapping the through hole  67  of the sealing member  61 , the valve body  62  is biased toward the sealing member  61  side. Therefore, the through hole  67  of the sealing member  61  is blocked by the valve body  62 . There is a gap held between the valve body  62  and the supply port  65 . There is also a gap held between the spring  63  and the supply port  65 . Therefore, the valve body  62  and the spring  63  can each be displaced in the supply port  65  along the extension direction of the supply port  65 . Moreover, in a state where the valve body  62  is housed in the supply port  65 , a gap between the valve body  62  and the inside of the supply port  65  functions as an ink flow passage. 
         [0099]    When the cartridge  7  is mounted to the holder  12  ( FIG. 3 ), as shown in  FIG. 13 , the ink introduction needle  23  is inserted into the through hole  67  of the sealing member  61 . At this time, the valve body  62  is pressed by the ink introduction needle  23 , and is displaced toward the spring fixing portion  66  side. The ink introduction needle  23  is formed to be hollow. Accordingly, as indicated by the arrow in the figure, ink can be supplied from the flow passage between the inside of the supply port  65  and the valve body  62  to the recording head  11  via the ink introduction needle  23  ( FIG. 1 ). 
         [0100]    Note that at a stage before the cartridge  7  is mounted to the holder  12 , the supply port  65  is sealed by a film  68  as shown in  FIG. 14 . If the cartridge  7  is mounted to the holder  12  in the state where the supply port  65  is sealed by the film  68 , the ink introduction needle  23  breaks the film  68 , and the ink introduction needle  23  is then inserted into the liquid supplying portion  51 . In addition, as described above, the internal diameter of the through hole  67  of the sealing member  61  is smaller than the external diameter of the ink introduction needle  23 . Therefore, when the ink introduction needle  23  is inserted into the liquid supplying portion  51 , the ink introduction needle  23  is press-fitted in the sealing member  61 . At this time, as shown in  FIG. 13 , a portion of the sealing member  61  that comes into contact with the ink introduction needle  23  is referred to as an abutment portion  69 . The abutment portion  69  corresponds to a portion of the liquid supplying portion that can abut on the liquid introduction needle. 
         [0101]    Moreover, in the cartridge  7 , a first recess portion  71  and a second recess portion  72  are formed in the first wall portion  41  as shown in  FIG. 10 . As shown in  FIG. 15 , the first recess portion  71  and the second recess portion  72  are each provided in such a direction to be recessed from the first wall portion  41  toward the second wall portion  42 , in other words, to be recessed in the Z axis direction. The first recess portion  71  and the second recess portion  72  are each open in the −Z axis direction. Note that  FIG. 15  shows a cross section of the cartridge  7  that is cut along a YZ plane intersecting the first recess portion  71 , the second recess portion  72  and the liquid supplying portion  51 . 
         [0102]    At the stage before the cartridge  7  is mounted to the holder  12 , the second recess portion  72  is blocked by a film  73  as shown in  FIG. 14 . When mounting the cartridge  7  to the holder  12 , the user peels off the film  73  from the cartridge  7 , and then mounts the cartridge  7  to the holder  12 . At this time, as shown in  FIG. 16 , the first projection  31  of the holder  12  corresponds to the first recess portion  71 , and the second projection  32  corresponds to the second recess portion  72 . In other words, the first projection  31  of the holder  12  is provided at a position corresponding to the first recess portion  71  of the cartridge  7 . Also, the second projection  32  of the holder  12  is provided at a position corresponding to the second recess portion  72  of the cartridge  7 . 
         [0103]    Here, in the cartridge  7 , in a planar view of the first wall portion  41  in a first direction from the first wall portion  41  toward the second wall portion  42 , in other words, in a planar view of the first wall portion  41  in the Z axis direction, the liquid supplying portion  51  is positioned closer to the fifth wall portion  45  than to the sixth wall portion  46  as shown in  FIG. 17 . Also, the first recess portion  71  is positioned closer to the fifth wall portion  45  than the liquid supplying portion  51 , and the second recess portion  72  is positioned closer to the sixth wall portion  46  than the liquid supplying portion  51 . Moreover, when the first wall portion  41  is equally divided into a first region  81 , a second region  82  and a third region  83  in a direction from the fifth wall portion  45  toward the sixth wall portion  46 , in other words, in the Y axis direction, the first recess portion  71  is positioned in the first region  81 , and the second recess portion  72  is positioned in the third region  83 . 
         [0104]    According to the above-described configuration, in the cartridge  7 , the first projection  31  can be inserted into the first recess portion  71 , and the second projection  32  can be inserted into the second recess portion  72 . Therefore, when mounting the cartridge  7  to the holder  12  of the carriage  9 , the first recess portion  71  and the second recess portion  72  can be used as guides for the mounting. It is possible to reduce variation in the orientation of the cartridge  7  relative to the carriage  9  when mounting the cartridge  7  to the carriage  9 . As a result, it is easy to improve the convenience when mounting the cartridge  7  to the carriage  9 . 
         [0105]    Moreover, in the cartridge  7 , the abutment portion  69  within the sealing member  61  that abuts on the ink introduction needle  23 , the contact portion  58  of the circuit substrate  53  ( FIG. 11 ), the first recess portion  71  and the second recess portion  72  are arranged along a straight line as shown in  FIG. 17 . In the cartridge  7 , the abutment portion  69  within the sealing member  61  that abuts on the ink introduction needle  23 , the contact portion  58  of the circuit substrate  53  ( FIG. 11 ), the first recess portion  71  and the second recess portion  72  are each one of the factors that regulate the position of the cartridge  7  relative to the carriage  9  when the cartridge  7  is mounted to the carriage  9 . By aligning the factors that regulate the position of the cartridge  7  relative to the carriage  9  along a straight line, it is possible to improve a function of guiding the cartridge  7  to the carriage  9  when mounting the cartridge  7  to the carriage  9 . 
         [0106]    Moreover, in the cartridge  7 , the engagement portion  54  of the lever  52 , the abutment portion  69  within the sealing member  61  that abuts on the ink introduction needle  23 , the first recess portion  71  and the second recess portion  72  are arranged along a straight line as shown in  FIG. 17 . In the cartridge  7 , the engagement portion  54  of the lever  52 , the abutment portion  69  within the sealing member  61  that abuts on the ink introduction needle  23 , the first recess portion  71  and the second recess portion  72  are each one of the factors that regulate the position of the cartridge  7  relative to the carriage  9  when the cartridge  7  is mounted to the carriage  9 . By aligning the factors that regulate the position of the cartridge  7  relative to the carriage  9  along a straight line, it is possible to improve a function of guiding the cartridge  7  to the carriage  9  when mounting the cartridge  7  to the carriage  9 . 
         [0107]    Also, in the cartridge  7 , as shown in  FIG. 15 , assuming a direction from the second wall portion  42  toward the first wall portion  41  to be a second direction, the liquid supplying portion  51  protrudes farther than a portion of the first wall portion  41  in which the first recess portion  71  is provided, by a first distance L 1  in the second direction. In other words, in the cartridge  7 , the liquid supplying portion  51  protrudes farther than the first wall portion  41  by the first distance L 1  in the −Z axis direction. 
         [0108]    Moreover, in the holder  12 , the first projection  31  protrudes farther than the ink introduction needle  23  by a second distance L 2  in the Z axis direction as shown in  FIG. 18 . Note that as described above, the Z axis direction corresponds to the first direction from the first wall portion  41  toward the second wall portion  42  in the cartridge  7 . In addition, in this embodiment, the second distance L 2  is greater than the first distance L 1 . 
         [0109]    According to such a configuration, as shown in  FIG. 19 , when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the first projection  31  can enter the first recess portion  71  before the ink introduction needle  23  reaches the liquid supplying portion  51 . Accordingly, the first projection  31  is likely to enter the first recess portion  71  before the ink introduction needle  23  enters the liquid supplying portion  51 . Therefore, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the first recess portion  71  is guided to the first projection  31 , making it easy to guide the liquid supplying portion  51  to the ink introduction needle  23 . As a result, it is easy to stabilize the orientation of the cartridge relative to the carriage  9  when the ink introduction needle  23  enters the liquid supplying portion  51 . 
         [0110]    Moreover, in the holder  12 , the second projection  32  protrudes farther than the ink introduction needle  23  by a third distance L 3  in the Z axis direction as shown in  FIG. 18 . In addition, in this embodiment, the third distance L 3  is greater than the first distance L 1 . According to such a configuration, as shown in  FIG. 19 , when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the second projection  32  can enter the second recess portion  72  before the ink introduction needle  23  reaches the liquid supplying portion  51 . Accordingly, in this embodiment, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , it is likely that the first projection  31  enters the first recess portion  71  and the second projection  32  enters the second recess portion  72  before the ink introduction needle  23  reaches the liquid supplying portion  51 . Accordingly, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the first recess portion  71  is guided to the first projection  31 , and the second recess portion  72  is guided to the second projection  32 , thereby making it easy to guide the liquid supplying portion  51  to the ink introduction needle  23 . As a result, it is easy to further stabilize the orientation of the cartridge  7  relative to the carriage  9  when the ink introduction needle  23  enters the liquid supplying portion  51 . 
         [0111]    Moreover, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the electrode pin  35  of the contact mechanism  34  abuts on the fifth wall portion  45  of the cartridge  7 , and the electrode pin  35  flexes in the −Y axis direction, as shown in  FIG. 19 . Note that in the cartridge  7 , the first recess portion  71  and the contact portions  58  of the circuit substrate  53  ( FIG. 11 ) are provided at positions at which they oppose each other such that the fifth wall portion  45  is positioned therebetween. 
         [0112]    Furthermore, in the holder  12 , as shown in  FIG. 18 , the second distance L 2  is greater than the third distance L 3 . According to such a configuration, as shown in  FIG. 19 , when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the first projection  31  is likely to enter the first recess portion  71  before the second projection  32  enters the second recess portion  72 . Therefore, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the first recess portion  71  is likely to be guided to the first projection  31  before the second recess portion  72  is guided to the second projection  32 . In other words, the first recess portion  71  is likely to be guided before the second recess portion  72 . 
         [0113]    In addition, the liquid supplying portion  51  of the cartridge  7  is provided at a position closer to the first recess portion  71  than to the second recess portion  72 . Accordingly, the liquid supplying portion  51  is closer to the first recess portion  71  that is likely to be guided before the second recess portion  72 . Therefore, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , it is easy to guide, at an early stage, the liquid supplying portion  51  that is closer to the first recess portion  71 , thus making it easy to stabilize the orientation of the cartridge  7  relative to the carriage  9  when the ink introduction needle  23  enters the liquid supplying portion  51 . As a result, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the ink introduction needle  23  is easily inserted into the liquid supplying portion  51  in a stable manner. 
         [0114]    Also, the contact portions  58  of the circuit substrate  53  of the cartridge  7  ( FIG. 11 ) are provided on the fifth wall portion  45  that is closer to the first recess portion  71  than to the second recess portion  72 . Accordingly, the contact portions  58  are closer to the first recess portion  71  that is likely to be guided before the second recess portion  72 . Therefore, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the contact portions  58  that are closer to the first recess portion  71  are likely to be guided at an early stage, and thus it is easy to stabilize the orientation of the cartridge  7  relative to the carriage  9  when the contact portions  58  come into contact with the electrode pins  35  of the contact mechanism  34 . As a result, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the contact portions  58  are easily brought into contact with the electrode pins  35  in a stable manner. 
         [0115]    Subsequently, when the cartridge  7  further enters the holder  12 , as shown in  FIG. 20 , the engagement portion  54  of the lever  52  engages with the engaging portion  33  of the holder  12 . Accordingly, the cartridge  7  is mounted to the carriage  9 . At this time, in the state where mounting of the cartridge  7  to the carriage  9  is complete, a gap is provided between the first projection  31  and the first recess portion  71  in the Z axis direction. Also, a gap is provided between the second projection  32  and the second recess portion  72  in the Z axis direction. With such settings, even if the heights in the Z axis direction of the first projection  31  and the second projection  32  vary due to dimension tolerance or error, it is easy to avoid variation in the position in the Z axis direction of the cartridge  7  relative to the holder  12 . 
         [0116]    Also, at this time, as shown in  FIG. 20 , the electrode pin  35  of the contact mechanism  34  abut on the circuit substrate  53  of the cartridge  7 , and the electrode pin  35  flexes farther in the −Y axis direction. As described above, in the cartridge  7 , the first recess portion  71  and the contact portion  58  of the circuit substrate  53  ( FIG. 11 ) are provided at positions at which they oppose each other such that the fifth wall portion  45  is positioned therebetween. Therefore, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , the contact portion  58  of the circuit substrate  53  of the cartridge  7  ( FIG. 11 ) and the fifth wall portion  45  are positioned between the electrode pin  35  of the contact mechanism  34  and the first projection  31 . 
         [0117]    This makes it easy to further stabilize the orientation of the cartridge relative to the carriage  9  when the cartridge  7  is mounted to the holder  12  of the carriage  9 . Therefore, it is easy to stabilize the orientation of the cartridge  7  relative to the carriage  9  when the contact portion  58  comes in to contact with the electrode pin  35  of the contact mechanism  34 . As a result, when the cartridge  7  is mounted to the holder  12  of the carriage  9 , it is easy to bring the contact portion  58  into contact with the electrode pin  35  in a stable manner. 
         [0118]    Moreover, according to this configuration, it becomes easy to prevent the electrode pins  35  of the carriage  9  from being separated from the contact portions  58  of the circuit substrate  53 , and prevent these positions from becoming deviated from each other when the cartridge  7  is mounted to the carriage  9  and the carriage  9  is moved. For example, when the printer  5  executes a printing operation, there are cases where vibration or the like is applied to the cartridge  7  in accordance with reciprocal movement of the carriage  9 , and even in such a situation, it becomes possible to appropriately maintain the connection relationship between the electrode pins  35  of the carriage  9  and the contact portions  58  of the cartridge  7 . 
         [0119]    Note that a configuration in which the first projection  31  and the first recess portion  71  abut on each other in the Z axis direction, and a configuration in which the second projection  32  and the second recess portion  72  abut on each other in the Z axis direction can also be adopted. With the configuration in which the first projection  31  and the first recess portion  71  abut on each other in the Z axis direction and the configuration in which the second projection  32  and the second recess portion  72  abut on each other in the Z axis direction, it is possible to improve the positional accuracy of the cartridge  7  relative to the holder  12  in the Z axis direction. 
         [0120]    In this case, a configuration can be adopted in which the first projection  31  abuts on the first recess portion  71  in the Z axis direction, and a gap in the Z axis direction is provided between the second projection  32  and the second recess portion  72 . With this configuration, out of the first recess portion  71  and the second recess portion  72 , the first recess portion  71  that is closer to the liquid supplying portion  51  can regulate the position in the Z axis direction of the cartridge  7  relative to the holder  12 . This makes it possible to improve the positional accuracy in the Z axis direction of the liquid supplying portion  51  relative to the holder  12 . 
         [0121]    A configuration can also be adopted in which the second projection  32  abuts on the second recess portion  72  in the Z axis direction, and a gap in the Z axis direction is provided between the first projection  31  and the first recess portion  71 . With this configuration, out of the first recess portion  71  and the second recess portion  72 , the second recess portion  72  that is farthest away from the liquid supplying portion  51  can regulate the position in the Z axis direction of the cartridge  7  relative to the holder  12 . Accordingly, even if the position in the Z axis direction at which the second recess portion  72  abuts on the second projection  32  varies due to dimension tolerance or error, it is possible to reduce variation in the position in the Z axis direction of the liquid supplying portion  51  relative to the holder  12 . 
         [0122]    In the state where mounting of the cartridge  7  to the carriage  9  is complete, the cartridge  7  can be removed from the holder  12  by releasing the engagement between the engagement portion  54  of the lever  52  and the engaging portion  33  of the holder  12 . In this manner, the cartridge  7  is mounted to and removed from the carriage  9 . 
       Second Embodiment 
       [0123]    A liquid ejecting system  100  in a second embodiment will be described. The liquid ejecting system  100  has a printer  101  and a cartridge  102  as shown in  FIG. 21 . The printer  101  has a detecting unit  91 . The printer  101  has a configuration in which the detecting unit  91  is added to the printer  5  in the first embodiment. Except for this, the printer  101  has a configuration similar to that of the printer  5 . Therefore, in the following description, the same reference signs as those of the constituent elements of the printer  5  are given to the constituent elements of the printer  101  that are similar to the constituent elements of the printer  5 , and detailed description is omitted. 
         [0124]    In this embodiment, the detecting unit  91  can detect the residual quantity of ink in the cartridge  102 . In this embodiment, a configuration is adopted in which the residual quantity of ink in the cartridge  102  is optically detected. With this configuration, the detecting unit  91  has an optical element. In this embodiment, as an example of the optical element, an optical sensor that has a light-emitting element and a light receiving element is adopted. In this optical sensor, when the light receiving element detects light from the light-emitting element, a detection signal of a high level is output (ON state), and when the light receiving element does not detect light from the light-emitting element, a detection signal of a low level is output (OFF state). Note that the ON state and the OFF state may be reversed. 
         [0125]    The cartridge  102  has a detection target unit  92  as shown in  FIG. 22 . The cartridge  102  has a configuration in which the detection target unit  92  is added to the cartridge  7  in the first embodiment. Except for this, the cartridge  102  has a configuration similar to that of the cartridge  7 . Therefore, in the following description, the same reference signs as those of the constituent elements of the cartridge  7  are given to the constituent elements of the cartridge  102  that are similar to the constituent elements of the cartridge  7 , and detailed description is omitted. 
         [0126]    The detection target unit  92  has an optical part. In this embodiment, a prism  93  serves as an example of the optical part. The detection target unit  92  is provided in the first wall portion  41  of the cartridge  102 . The detection target unit  92  is sunk into the liquid container  47  through the first wall portion  41 . In addition, in this embodiment, a window portion  95  is formed in the holder  12 . The window portion  95  is formed to pass through the bottom portion  22  of the holder  12 . In a state where the cartridge  102  is mounted to the holder  12 , the window portion  95  is formed at a position at which it overlaps the detection target unit  92  of the cartridge  102  along the Z axis. 
         [0127]    The detecting unit  91  shown in  FIG. 21  is provided at a position at which it overlaps the path of the detection target unit  92  when the carriage  9  is moved along the X axis. Detection processing is then performed at a position at which the detection target unit  92  and the detecting unit  91  overlap each other along the Z axis. When detection processing is performed, as shown in  FIG. 23 , a beam  96  from the light-emitting element of the detecting unit  91  is incident on the prism  93  of the detection target unit  92  via the window portion  95 . At this time, if the liquid level of ink in the liquid container  47  is higher than a reflective face  97 , the beam  96  that is incident on the prism  93  exits the prism  93  from the reflective face  97 . Therefore, if the liquid level of the ink in the liquid container  47  is higher than the reflective face  97 , the optical sensor of the detecting unit  91  enters the OFF state. 
         [0128]    On the other hand, if the liquid level of the ink in the liquid container  47  is lower than the reflective face  97 , the beam  96  that is incident on the prism  93  is reflected by the reflective face  97  and then exits the prism  93  toward the detecting unit  91 . Therefore, if the liquid level of the ink in the liquid container  47  is lower than the reflective face  97 , the optical sensor of the detecting unit  91  enters the ON state. Such change of the detecting unit  91  between the ON state and the OFF state makes it possible to detect the residual quantity of the ink in the liquid container  47 . 
         [0129]    Also in the second embodiment, an effect similar to that of the first embodiment can be obtained. Moreover, in the second embodiment, the residual quantity of ink contained in the cartridge  102  can be detect, and thus the convenience of the liquid ejecting system  100  improves. 
         [0130]    In the second embodiment, the detection target unit  92  of the cartridge  102  is positioned between the first recess portion  71  and the second recess portion  72 . Specifically, in a planar view of the first wall portion  41  in a direction from the first wall portion  41  toward the second wall portion  42  (the Z axis direction), as shown in  FIG. 24 , the detection target unit  92  is positioned between the first recess portion  71  and the second recess portion  72 . 
         [0131]    According to such a configuration, in the liquid ejecting system  100 , the first projection  31  can be inserted into the first recess portion  71  of the cartridge  102 , and the second projection  32  can be inserted into the second recess portion  72 . Therefore, when the cartridge  102  is mounted to the holder  12  of the carriage  9 , the position of the first recess portion  71  can be regulated by the first projection  31 , and the position of the second recess portion  72  can be regulated by the second projection  32 . As a result, it is possible to reduce variation in the orientation of the cartridge  102  relative to the carriage  9  after the cartridge  102  is mounted to the holder  12  of the carriage  9 . As a result, it is easy to suppress deterioration of the detection accuracy in the detection target unit  92 . 
       Third Embodiment 
       [0132]    A cartridge  200  in a third embodiment will be described. The external dimensions of the cartridge  200  are different from the external dimensions of the cartridge  7  and the cartridge  102 . Except for this, the cartridge  200  has a configuration similar to that of the cartridge  7  and the cartridge  102 . Therefore, the same reference signs as those of the cartridge  7  and the cartridge  102  are given to the constituent elements of the cartridge  200  similar to those of the cartridge  7  and the cartridge  102 , and detailed description is omitted as appropriate. 
         [0133]    The cartridge  200  has the first wall portion  41  as shown in  FIG. 25 .  FIG. 25  illustrates a state where the cartridge  200  is seen in a planar view in the Z axis direction. The cartridge  200  also has the second wall portion  42  as shown in  FIG. 26 .  FIG. 26  illustrates a state where the cartridge  200  is seen in a planar view in the −Z axis direction. The cartridge  200  also has the third wall portion  43  as shown in  FIG. 27 .  FIG. 27  illustrates a state where the cartridge  200  is seen in a planar view in the X axis direction. 
         [0134]    The cartridge  200  also has the fourth wall portion  44  as shown in  FIG. 28 .  FIG. 28  illustrates a state where the cartridge  200  is seen in a planar view in the −X axis direction. The cartridge  200  also has the fifth wall portion  45  as shown in  FIG. 29 .  FIG. 29  illustrates a state where the cartridge  200  is seen in a planar view in the Y axis direction. The cartridge  200  also has the sixth wall portion  46  as shown in  FIG. 30 .  FIG. 30  illustrates a state where the cartridge  200  is seen in a planar view in the −Y axis direction. Note that similarly to the first embodiment and the second embodiment, the first to sixth wall portions  41  to  46  are not limited to a flat wall, and may include recessions and protrusions, or may include a curved surface. 
         [0135]    As shown in  FIG. 25 , the distance between the third wall portion  43  and the fourth wall portion  44  of the cartridge  200 , in other words, the width dimension along the X axis of the cartridge  200  is different from that of the cartridge  7  and the cartridge  102 . Except for this, the cartridge  200  has a configuration similar to that of the cartridge  7  and the cartridge  102 . In the cartridge  200 , the width dimension along the X axis of the cartridge  200  is greater than that of the cartridge  7  and the cartridge  102 . Accordingly, as shown in  FIG. 31 , the volume of the liquid container  47  is greater than the volume of the liquid container  47  of the cartridge  7  and the cartridge  102 . According to such a configuration, the volume of ink that can be contained in the cartridge  200  is greater than that of the cartridge  7  and the cartridge  102 . Accordingly, it is possible to reduce the frequency of replacing the cartridge  200  in the liquid ejecting system  1  and the liquid ejecting system  100 . 
         [0136]    Also in the cartridge  200 , similarly to the first embodiment and the second embodiment, in a planar view of the first wall portion  41  in the first direction from the first wall portion  41  toward the second wall portion  42 , in other words, in a planar view of the first wall portion  41  in the Z axis direction, the liquid supplying portion  51  is positioned closer to the fifth wall portion  45  than to the sixth wall portion  46  as shown in  FIG. 25 . Also, the first recess portion  71  is positioned closer to the fifth wall portion  45  than the liquid supplying portion  51 , and the second recess portion  72  is positioned closer to the sixth wall portion  46  than the liquid supplying portion  51 . In addition, when equally dividing the first wall portion  41  into the first region  81 , the second region  82  and the third region  83  in a direction from the fifth wall portion  45  toward the sixth wall portion  46 , in other words, in the Y axis direction, the first recess portion  71  is positioned in the first region  81 , and the second recess portion  72  is positioned in the third region  83 . Note that in the cartridge  200 , the lever  52 , the circuit substrate  53 , the first recess portion  71 , the liquid supplying portion  51 , and the second recess portion  72  are positioned closer to the fourth wall portion  44  than to the third wall portion  43  in the X axis direction. Furthermore, in a configuration in which the detection target unit  92  is provided, the detection target unit  92  is also positioned closer to the fourth wall portion  44  than to the third wall portion  43  in the X axis direction. 
         [0137]    Also in the third embodiment, effects similar to those of the first embodiment and the second embodiment are obtained. 
       Modified Example 1 
       [0138]    A liquid supplying unit for supplying a liquid to a liquid ejecting apparatus is not limited to the cartridge  7 , the cartridge  102  and the cartridge  200 , which are examples of the liquid supplying unit. Another example of the liquid supplying unit will be described as Modified Example 1. A liquid supplying unit  401  of Modified Example 1 has, as shown in  FIG. 32 , the above-described the cartridge  7 , the cartridge  102  or the cartridge  200 , a tank  402  and an ink supplying tube  403 . The tank  402  contains ink to be supplied to the above-described the cartridge  7  or the cartridge  102 . The ink supplying tube  403  guides the liquid from the tank  402  to the cartridge  7 , the cartridge  102 , or the cartridge  200 . The ink supplying tube  403  has flexibility. 
         [0139]    Moreover, in the liquid supplying unit  401  of Modified Example 1, the cartridge  7 , the cartridge  102  or the cartridge  200  is mounted to the carriage  9  ( FIGS. 1 and 21 ), while the tank  402  is provided independently from the carriage  9 . In other words, in Modified Example 1, the tank  402  is not mounted to the carriage  9 . Therefore, it is possible to increase the amount of ink that can be supplied to the liquid ejecting apparatus while reducing the load on the carriage  9 . Furthermore, if a configuration is adopted in which the tank  402  can be refilled with new ink, it is possible to reduce or eliminate a suspension period of the liquid ejecting apparatus due to ink shortage. 
       Modified Example 2 
       [0140]    In the above-described cartridge  7 , the cartridge  102  and the cartridge  200 , the first recess portion  71  is open in the first wall portion  41 . In other words, in the above-described cartridge  7 , the cartridge  102  and the cartridge  200 , the first recess portion  71  is open in the −Z axis direction. However, the direction in which the first recess portion  71  is open is not limited thereto. For example, as shown in  FIG. 33 , a configuration can also be adopted in which the first recess portion  71  is also open in the fourth wall portion  44 . In this case, the first recess portion  71  is open in a direction from the second wall portion  42  toward the first wall portion  41  (the −Z axis direction) and in a direction from the third wall portion  43  toward the fourth wall portion  44  (the X axis direction). In other words, with this configuration, the first recess portion  71  is open in the first wall portion  41  and the fourth wall portion  44 . According to such a configuration, the first recess portion  71  is open in two directions, and thus it is possible to make it easy to insert the first projection  31  into the first recess portion  71 . This can make it easy to mount the cartridge  7 , the cartridge  102  or the cartridge  200  to the carriage  9 . Note that the configuration of the first recess portion  71  is not limited to the configuration of being open in the first wall portion  41  and the fourth wall portion  44 . As the configuration of the first recess portion  71 , a configuration can also be adopted in which the first recess portion  71  is open in the first wall portion  41  and the third wall portion  43 . With this configuration as well, a similar effect can be obtained. 
       Modified Example 3 
       [0141]    Also, in the above-described cartridge  7 , cartridge  102  and cartridge  200 , the second recess portion  72  is open in the first wall portion  41 . In other words, in the above-described cartridge  7 , the cartridge  102  and the cartridge  200 , the second recess portion  72  is open in the −Z axis direction. However, the direction in which the second recess portion  72  is open is not limited thereto. For example, a configuration can also be adopted in which the second recess portion  72  is also open in the fourth wall portion  44  as shown in  FIG. 34 . In this case, the second recess portion  72  is open in a direction from the second wall portion  42  toward the first wall portion  41  (the −Z axis direction) and in a direction from the third wall portion  43  toward the fourth wall portion  44  (the X axis direction). In other words, with this configuration, the second recess portion  72  is open in the first wall portion  41  and the fourth wall portion  44 . According to such a configuration, the second recess portion  72  is open in two directions, and thus it is possible to make it easy to insert the second projection  32  into the second recess portion  72 . This can make it easy to mount the cartridge  7 , the cartridge  102  or the cartridge  200  to the carriage  9 . Note that the configuration of the second recess portion  72  is not limited to a configuration of being open in the first wall portion  41  and the fourth wall portion  44 . As the configuration of the second recess portion  72 , a configuration can also be adopted in which the second recess portion  72  is open in the first wall portion  41  and the third wall portion  43 . With this configuration as well, a similar effect can be obtained. 
         [0142]    The invention is not limited to an inkjet printer and an ink cartridge thereof, and can also be applied to any printing apparatus that ejects a liquid other than ink and a cartridge used for such a printing apparatus. For example, the invention can be applied to various printing apparatuses as follows and cartridges thereof: 
         [0000]    (1) an image recording apparatus such as a facsimile apparatus, (2) a printing apparatus that ejects color material used for manufacturing color filters for an image display device such as a liquid crystal display, (3) a printing apparatus that ejects electrode materials used for forming electrodes for an organic EL (Electro Luminescence) display, an FED (Field Emission Display) and the like, (4) a printing apparatus that ejects a liquid containing biological organic matter used for manufacturing biochips, (5) a sample printing apparatus serving as a precision pipette, (6) a printing apparatus for a lubricant, (7) a printing apparatus for a resin liquid, (8) a printing apparatus that ejects a lubricant onto precision instruments such as time pieces and cameras with pinpoint accuracy, (9) a printing apparatus that ejects a transparent resin liquid such as an ultraviolet-curing resin liquid onto a substrate in order to form, for example, a hemispherical micro lens (optical lens) used in an optical communication element or the like, (10) a printing apparatus that ejects an acid or alkali etching solution in order to etch a substrate or the like, and (11) a printing apparatus provided with a liquid ejecting head for discharging a minute amount of any other liquid droplets. 
         [0143]    Note that “liquid droplets” refer to a state of a liquid that is discharged from a printing apparatus, and includes a liquid that leaves a trail in the form of particles, tears, or threads. It suffices for the “liquid” to be a material that can be ejected by the printing apparatus. For example, it suffices for the “liquid” to be a material in a state where the substance is in the liquid phase, and the “liquid” includes materials in a liquid state such as high- or low-viscosity liquids, and materials in a liquid state such as sols, gel waters, other inorganic solvents, organic solvents, solutions, liquid resins, and liquid metals (molten metals). The “liquid” includes not only liquids in the form of one state of a substance, but also solvents into which particles of a functional material composed of a solid matter such as a pigment or metal particles has been dissolved, dispersed or mixed, and the like. The “liquid” as described above can also be expressed as “liquid body”. Representative examples of liquids and liquid bodies include ink, such as was described in the above embodiments, liquid crystal and the like. Herein, the term “ink” encompasses a variety of compositions in the form of a liquid, such as general water-soluble inks and oil-soluble inks as well as gel inks, and hot melt inks. 
         [0144]    Note that the invention is not limited to the above embodiments and 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 examples that correspond to the technical features in the aspects described in the summary of the invention may 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.