Patent Publication Number: US-11639060-B2

Title: Ink refill container, ink refill system, and ink refill adapter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 17/070,064, filed Oct. 14, 2020; which is a continuation of U.S. application Ser. No. 16/857,065, filed Apr. 23, 2020; which is a continuation of U.S. application Ser. No. 16/307,625, filed Dec. 6, 2018; which is the national phase entry of PCT/JP2017/021057, filed Jun. 7, 2017; which claims priority to Japanese Application No. 2016-116155, filed Jun. 10, 2016; Japanese Application No. 2016-203332, filed Oct. 17, 2016; and Japanese Application No. 2016-208864, filed Oct. 25, 2016; the contents of all of which are incorporated by reference herein in their entirety. 
    
    
     FIELD 
     The present invention relates to an ink refill container that can appropriately refill ink to an ink tank that stores ink to be refilled to a recording device, an ink refill system that contains the ink refill container, and an ink refill adapter that uses the ink refill system. 
     BACKGROUND 
     In a recording device, previously, that performs recording by ejecting ink onto a medium, an ink tank that stores ink is connected to the recording device in a manner that allows the ink tank to refill the ink. In addition, when only a small amount of ink remains in the ink tank in the recording device, an ink refill container is used to externally refill the ink to the ink tank (see, for example, Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     [Patent Literature 1] JP 2001-146021A 
     SUMMARY 
     Technical Problem 
     This operation of refilling the ink tank with the ink needs to be carried out appropriately to prevent incorrect refilling or other problems. However, this refilling operation has generally been carried out by a user of the recording device. Therefore, there is a need to further improve, for example, the ink refill container to allow the user to correctly perform the ink refill operation. 
     The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an ink refill container that can appropriately refill ink to an ink tank, an ink refill system that contains the ink refill container, and an ink refill adapter that uses the ink refill system. 
     Solution to Problem 
     Means and the effects thereof for solving the above-mentioned problem are described below. 
     An ink refill container for solving the above-mentioned problem is an ink refill container configured to refill ink to an ink tank configured to store ink, the ink refill container including a container main body including an ink storage chamber configured to store ink to be refilled to the ink tank, an ink outlet-forming portion that is provided on an end portion of the container main body, in which an ink outlet that allows ink to flow out from the ink storage chamber is formed, and a valve provided in the ink outlet-forming portion, configured to seal the ink outlet in an openable/closeable manner, in which the ink outlet-forming portion includes a positioning portion at a position on an outer side of the ink outlet-forming portion, the positioning portion being closer to the container main body than the valve is to the container main body in a central axis direction of the ink outlet, and in which the positioning portion abuts against a part of the ink tank when the valve is opened and positioned with respect to the ink tank. 
     With this configuration, because the valve opens while being positioned with respect to the ink tank when the ink is refilled from the ink refill container to the ink tank, problems such as ink spillage and incorrect ink refilling, which may occur when the valve displaces as the valve opens, can be suppressed, and the ink can be correctly refilled to the ink tank. 
     In addition, in the above-mentioned ink refill container, the valve is preferably provided with at least one or more slits in an elastic member configured to seal the ink outlet, and opens when the slit is pushed inward from outside the ink outlet. 
     With this configuration, an ink refill container with a simple structure and few components can be provided. 
     In addition, in the ink refill container, the positioning portion is preferably positioned radially outward of the ink outlet in a radial direction of the ink outlet when viewed from the central axis direction of the ink outlet. 
     With this configuration, when the ink is refilled from the ink refill container to the ink tank, because the positioning portion in the ink refill container abuts against the part of the ink tank while being positioned on an outer side of the ink outlet in the radial direction, the ink can be refilled in a stable manner. 
     In addition, in the ink refill container, the positioning portion is preferably formed as a member separate to the ink outlet-forming portion. 
     With this configuration, the positioning portion can be optimized in accordance with the design specifications of the ink tank and the ink refill container. 
     An ink refill system for solving the above-mentioned problem includes an ink storage chamber that configured to store ink, a needle that extends and includes a flow passage for communicating the inside and the outside of the ink storage chamber, and a receiving surface that extends in a direction that intersects a direction in which the needle extends at a position further outside than a tip of the needle, in which the receiving surface forms the part of the ink tank; and the ink refill container configured as described above, and in which, the positioning portion in the ink refill container abuts against the receiving surface when the tip of the needle is inserted into the ink outlet to open the valve. 
     With this configuration, when the needle of the ink tank is inserted into the ink outlet of the ink refill container to open the valve, the positioning portion of the ink refill container abuts against the receiving surface of the ink tank, and determines the relative positional relationship between the valve and the needle. Therefore, the valve can be appropriately opened by the needle, and the occurrence of incorrect ink refilling can be suppressed. 
     In addition, in the ink refill system, the ink tank preferably includes a concave portion that opens in the direction in which the needle extends in an area that forms the outer side of the needle in a radial direction centered about the needle, and the ink refill container preferably includes a convex portion configured to fit into the concave portion when the tip of the needle is inserted into the ink outlet in a region that forms the outer side of the ink outlet in a radial direction centered about the ink outlet. 
     With this configuration, the needle is not inserted into the ink outlet unless the convex portion of the ink refill container is fit into the concave portion of the ink tank, and hence a state in which the ink tank and the ink refill container are incorrectly connected can be suppressed. 
     In addition, in the ink refill system, the ink refill container preferably includes the positioning portion at a position on an outer side of the ink outlet-forming portion, the positioning portion being closer to the container main body than the convex portion is to the container main body in the central axis direction of the ink outlet. 
     With this configuration, a state in which the ink tank and the ink refill container are incorrectly connected can be suppressed. Further, appropriate positioning of the insertion of the needle into the ink outlet of the ink refill container can be ensured. 
     In addition, in the ink refill system, the tip of the needle of the ink tank is preferably located closer to the ink storage chamber than the receiving surface is located to the ink storage chamber. 
     With this configuration, the tip of the needle of the ink tank does not protrude out further than the receiving surface. Therefore, even if ink adheres to the tip of the needle, a risk of the ink adhering to the ink refill container or the hand of a user performing the ink refill operation can be reduced. 
     In addition, in the ink refill system, the flow passage of the needle of the ink tank is preferably formed of two flow passages with tip openings arranged in parallel in a radial direction about the center of the needle, and, when one of the two flow passages functions as an ink flow passage to allow the flow of ink, the other flow passage preferably functions as an air flow passage to allow the flow of air. 
     With this configuration, when the ink refill container is connected to the ink tank while being inclined along a radial direction in which the two flow passages are arranged from the direction in which the needle extends, one flow passage among the two flow passages located on a side on which the ink outlet of the ink refill container approaches first functions as the ink flow passage, and the other flow passage functions as the air flow passage. Therefore, because the user can use either one of the two flow passages as the ink flow passage, the user can perform the ink refill operation quickly without needing to choose the flow passage to be the ink flow passage. 
     Further, another ink refill system for solving the above-mentioned problem includes an ink tank including an ink storage chamber configured to store ink, an ink inlet that allows ink to flow into the ink storage chamber, and a concave portion formed in a region that forms an outer side of the ink inlet in a radial direction centered about the ink inlet; and an ink refill container including an ink storage chamber configured to store ink to be refilled to the ink tank, an ink outlet that allows the ink to flow out from the ink storage chamber, and a convex portion formed so as to fit into the concave portion in a region that forms an outer side of the ink outlet in a radial direction centered about the ink outlet, in which the ink tank includes a first concave/convex portion located at a position inside of the concave portion, the first concave/convex portion being closer to the bottom of the concave portion than the opening edge of the concave portion is to the bottom of the concave portion, and the ink refill container includes a second concave/convex portion in the convex portion, the second concave/convex portion being configured to engage with the first concave/convex portion of the ink tank. 
     With this configuration, by fitting the convex portion of the ink refill container into the concave portion of the ink tank, and engaging the second concave/convex portion on the outer surface of the convex portion with the first concave/convex portion on the inner surface of the concave portion, the user can recognize that an ink refill container appropriate for the ink tank has been connected. Therefore, because a state in which the ink tank and the ink refill container are incorrectly connected can be suppressed, and the first concave/convex portion is located at a position inside of the concave portion, the first concave/convex portion being closer to the bottom of the concave portion than the opening edge of the concave portion is to the bottom of the concave portion, the convex portion of the ink refill container can be easily guided to the bottom side from the opening side of the concave portion of the ink tank, and insertion thereof can be performed easily. 
     In addition, in the ink tank of the ink refill system, a depth direction of the concave portion preferably corresponds to a central axis direction of the ink inlet, the first concave/convex portion is preferably provided so as to extend along the depth direction of the concave portion on the inner surface of the concave portion, and in the ink refill container, the ink outlet is preferably connected to the ink inlet when the convex portion is fitted into the concave portion and the second concave/convex portion is engaged with the first concave/convex portion. 
     With this configuration, the second concave/convex portion on the outer surface of the convex portion of the ink refill container can be engaged with the first concave/convex portion provided so as to extend along the depth direction of the concave portion on the inner surface of the concave portion of the ink tank by the convex portion being fitted into the concave. As a result, it is easy to recognize the connection direction of the ink outlet of the ink refill container to the ink inlet of the ink tank. 
     In addition, in the ink refill system, the depth direction of the concave portion in the ink tank is preferably a direction that intersects with a horizontal direction and faces downward when the ink outlet is connected to the ink inlet. 
     With this configuration, under a state in which the ink outlet of the ink refill container is connected to the ink inlet of the ink tank, the ink can be prevented from returning to the ink storage chamber from the ink outlet of the ink refill container, and the ink can be appropriately refilled to the ink tank from the ink refill container. 
     Yet another ink refill system for solving the above-mentioned problem includes an ink tank including an ink storage chamber configured to store ink, an ink inlet that allows the ink to flow into the ink storage chamber, a plurality of first fitting portions that are formed in a region that forms an outer side of the ink inlet in a radial direction centered about the ink inlet so as to be point symmetrical about the ink inlet; and an ink refill container including an ink storage chamber configured to store ink to be refilled to the ink tank, an ink outlet that allows the ink to flow out from the ink storage chamber, and a second fitting portion formed so as to be fittable into the first fitting portion, formed in a region that forms an outer side of the ink outlet in the radial direction centered about the ink outlet. 
     With this configuration, even when the second fitting portion in the ink refill container is fitted into any one of the plurality of fitting portions formed point symmetrically about the ink inlet in the ink tank, the ink outlet in the ink refill container can be connected to the ink inlet of the ink tank, and hence components can be easily connected to the ink tank of the ink refill container when the ink is refilled. 
     Further, a further ink refill system for solving the above-mentioned problem includes an ink tank that contains an ink storage chamber configured to store ink, an ink inlet that allows the ink to flow into the ink storage chamber, and a first fitting portion formed in a region that forms an outer side of the ink inlet in a radial direction centered about the ink inlet; and an ink refill container that contains an ink storage chamber configured to store ink to be refilled to the ink tank, an ink outlet that allows the ink to flow out from the ink storage chamber, and a second fitting portion formed so as to be fittable into the first fitting portion in a region that forms the outer side of the ink outlet in the radial direction centered about the ink outlet, in which the ink tank includes a first portion that shows information associated with the ink stored in the ink storage chamber, the ink refill container includes a second portion that shows information associated with the ink housed in the ink storage chamber, and the first portion and the second portion are provided at an externally visually recognizable position when the second fitting portion in the ink refill container is fit into the first fitting portion of the ink tank. 
     With this configuration, when the ink refill container is connected to the ink tank to refill the ink, the first portion and the second portion can be easily visually recognized to check whether or not the ink to be refilled is suitable. 
     Yet another ink refill system for solving the above-mentioned problem includes an ink tank that contains an ink storage chamber configured to store ink, an ink inlet that allows the ink to flow into the ink storage chamber, and a concave portion formed in a region that forms an outer side of the ink inlet in a radial direction centered about the ink inlet; and an ink refill container that contains an ink storage chamber configured to store ink to be refilled to the ink tank, an ink outlet that allows the ink to flow out from the ink storage chamber, and a convex portion formed so as to be fittable into the concave portion in a region that forms an outer side of the ink outlet in a radial direction centered about the ink outlet, in which the convex portion of the ink refill container protrudes further than the ink outlet in a direction opposing the ink storage chamber in a central axis direction of the ink outlet. 
     With this configuration, when the ink is refilled, because the convex portion protrudes further than the ink outlet in the ink refill container, a risk of the ink outlet touching the hand of the user or the vicinity around the ink tank can be reduced, and contamination due to the ink adhering to those places can be suppressed. 
     Conversely, the ink outlet can be made to protrude further than the convex portion in the direction opposing the ink storage chamber in the central axis direction. In this case, the ink outlet becomes easier to see when the ink is refilled. 
     In addition, in the above-mentioned ink refill system, the convex portion of the ink refill container preferably protrudes further outward than an outer peripheral surface of a container main body provided with the ink storage chamber in the radial direction centered about the ink outlet. 
     With this configuration, the user can easily visually recognize the convex portion when viewing the ink refill container, and the convex portion of the ink refill container can be easily fitted into the concave portion of the ink tank when the ink is refilled. As a result, incorrect connection of the ink refill container to the ink tank can be suppressed. 
     In addition, in the above-mentioned ink refill system, the convex portion of the ink refill container is preferably formed further inward than an outer peripheral surface of a container main body provided with the ink storage chamber in the radial direction centered about the ink outlet. 
     With this configuration, when the ink outlet of the ink refill container is connected to the ink inlet of the ink tank, the convex portion of the ink refill container is less likely to become a hindrance. 
     An ink refill adapter for solving the above-mentioned problem is an ink refill adapter in which an ink refill container and an ink tank are connected to each other when ink is refilled to the ink tank from the ink refill container, the ink refill adapter including a tank engaging portion configured to engage a plurality of ink tanks each containing an ink storage chamber configured to store ink as a group, a plurality of ink inlets each provided with the ink tank so as to allow the ink to flow into the ink storage chamber from the ink outlet of the ink refill container, and a plurality of identification units each provided to one of the plurality of ink inlets, with which it is possible to identify the ink refill container containing the ink outlet configured to connect to the ink inlet. 
     With this configuration, by giving the ink tanks a generic common structure, and engaging the tank engaging portions of the refill adapter by grouping the plurality of ink tanks, the ink refill adapter can be implemented with a structure that can suppress incorrect connection of the ink refill container when the ink is refilled. 
     Another ink refill adapter for solving the above-mentioned problem is an ink refill adapter mounted to an ink tank under a state in which ink is refilled to the ink tank from the ink refill container, the ink refill adapter including an inlet forming portion that at least partly surrounds an ink inlet flow passage configured to be inserted through the inlet forming portion, the ink inlet flow passage provided in an ink tank so as to allow ink to flow into an ink storage chamber provided in the ink tank, an adapter-side positioning portion configured to engage with a tank-side positioning portion provided in the ink tank, configured to position the ink refill adapter with respect to the ink tank, and an identification unit with which it is possible to identify the ink refill container containing the ink outlet configured to connect to the ink inlet. 
     With this configuration, because the ink refill adapter is positioned with respect to the ink tank, displacement between the ink inlet flow passage portion provided in the ink tank and the inlet forming portion provided in the ink refill adapter can be suppressed. Therefore, the ink can be appropriately refilled from ink refill container to the ink tank via the ink refill adapter. 
     In addition, in the ink refill adapter, the plurality of inlet forming portions, the identification unit corresponding to the plurality of inlet forming portions, and the plurality of adapter-side positioning portions are preferably formed integrally. 
     With this configuration, because the inlet forming portions, identification unit, and adapter-side positioning portions are formed integrally, the ink refill adapter can be manufactured more easily than if these components were provided separately. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view for schematically illustrating a schematic configuration of a first embodiment of a recording device in a perspective state. 
         FIG.  2    is a perspective view for illustrating an ink refill unit that is provided in a casing of the recording device. 
         FIG.  3    is a plan view for illustrating the ink refill unit. 
         FIG.  4    is a partially broken cross-sectional view along the line  4 - 4  in  FIG.  3   . 
         FIG.  5    is a partially broken cross-sectional view along the line  5 - 5  in  FIG.  3   . 
         FIG.  6    is a perspective view for illustrating an ink refill container from which a cap has been removed. 
         FIG.  7    is a side view for illustrating the ink refill container. 
         FIG.  8    is a front view for illustrating the ink refill container. 
         FIG.  9    is a plan view for illustrating the ink refill container. 
         FIG.  10    is a cross-sectional view along the line  10 - 10  in  FIG.  9   . 
         FIG.  11    is a cross-sectional view along the line  11 - 11  in  FIG.  9   . 
         FIG.  12    is a partially broken cross-sectional front view for illustrating a state directly before ink is refilled to the ink tank. 
         FIG.  13    is a partially broken cross-sectional side view for illustrating a state directly before the ink is refilled to the ink tank. 
         FIG.  14    is a partially broken cross-sectional front view for illustrating a state while the ink is being refilled to the ink tank. 
         FIG.  15    is a partially broken cross-sectional side view for illustrating a state while the ink is being refilled to the ink tank. 
         FIG.  16    is a partially broken cross-sectional front view for illustrating a state in which a positioning portion of the ink refill container abuts against a receiving surface of the ink tank when the ink is refilled. 
         FIG.  17    is a partially broken cross-sectional side view for illustrating a state in which the positioning portion of the ink refill container abuts against the receiving surface of the ink tank when the ink is refilled. 
         FIG.  18    is a perspective view for illustrating a multi-function printer that includes a recording device according to a second embodiment. 
         FIG.  19    is a perspective view for illustrating the multi-function printer when the ink is to be refilled to the ink tank. 
         FIG.  20    is a perspective view for illustrating a state in which a casing of the ink refill unit has been removed. 
         FIG.  21    is a partial perspective view for illustrating the ink tank. 
         FIG.  22    is a partial plan view for illustrating the ink tank. 
         FIG.  23    is a partial perspective view for illustrating the ink refill unit. 
         FIG.  24    is a partial plan view for illustrating the ink refill unit. 
         FIG.  25    is a perspective view from a lower surface side of an ink refill adapter. 
         FIG.  26    is a bottom view of the ink refill adapter. 
         FIG.  27    is a cross-sectional view along the line F 27 -F 27  in  FIG.  23   . 
         FIG.  28    is a cross-sectional view along the line F 28 -F 28  in  FIG.  23   . 
         FIG.  29    is a side view for illustrating an ink refill container according to a modification example. 
         FIG.  30    is a front view for illustrating the ink refill container according to the modification example. 
         FIG.  31    is a perspective view for illustrating an ink refill container according to another modification example. 
         FIG.  32    is a perspective view for illustrating an ink refill unit according to a modification example. 
         FIG.  33    is a perspective view for illustrating an ink refill adapter according to a modification example. 
         FIG.  34    is a partial perspective view for illustrating an ink refill container according to a modification example. 
         FIG.  35    is a plan view for illustrating an ink outlet and a second concave/convex portion according to a modification example. 
         FIG.  36    is a partial cross-sectional view for illustrating the ink refill container and a cap according to a modification example. 
         FIG.  37    is a schematic cross-sectional view for illustrating an ink outlet and a sealing portion according to a modification example. 
         FIG.  38    is a cross-sectional view for illustrating an ink outlet-forming portion. 
         FIG.  39    is a cross-sectional view for illustrating the ink outlet-forming portion, a valve, and a holder. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     A first embodiment of a recording device is described with reference to the figures. The recording device according to this embodiment is an ink-jet printer configured to record (print) an image or the like on a medium by ejecting ink onto the medium. 
     A recording device  21  illustrated in  FIG.  1    includes a rectangular casing  22  in which a left-right direction corresponds to a longitudinal direction.  FIG.  1    illustrates a simple perspective view of the inside of the casing  22  in the recording device  21 . A support stand  23  in which a left-right direction corresponds to a longitudinal direction is provided on a lower portion of the casing  22  closer to the rear of the casing  22  so that an upper surface thereof extends along a substantially horizontal direction. A paper P as an example of a medium is fed toward the front, which is a feed direction, while being supported by the upper surface of the support stand  23 . A guide shaft  24  that extends along the left-right direction is erected at an upper position of the support stand  23  in the casing  22 , and a carriage  26  provided with a recording head  25  configured to eject ink on a lower surface side thereof is supported by the guide shaft  24 . More specifically, the carriage  26  is supported by the guide shaft  24  so as to freely move back and forth in the left-right direction under a state in which the guide shaft  24  is inserted into a bearing hole  27  that is open in the left-right direction. 
     In the casing  22 , a drive pulley  28  and a driven pulley  29  are each rotatably supported at positions near opposite ends of the guide shaft  24 . An output shaft of a carriage motor  30  is linked to the drive pulley  28 , and an endless timing belt  31  linked to a portion of the carriage  26  is wrapped around the drive pulley  28  and the driven pulley  29 . When the carriage motor  30  is driven to reciprocally move the carriage  26  along the left-right direction as a scanning direction of the paper P while being guided by the guide shaft  24  via the timing belt  31 , the paper P is fed to the front over the support stand  23 , and ink is ejected onto the paper P from the recording head  25  on the lower surface side of the carriage  26 . 
     At a position on a front side of the support stand  23  on a front surface side of the casing  22  illustrated in  FIG.  1   , the ink is ejected from the recording head  25  when the paper P is fed over the support stand  23  in the casing  22 , to thereby open a rectangular discharge port  32  for discharging the paper P that has been recorded on to the front side. The discharge port  32  is provided with a rectangular plate-shape discharge tray  33  that can support the paper P discharged from the casing  22  so that the discharge tray  33  is freely retractable toward the front, which is a discharge direction. In the discharge port  32 , a paper refill cassette  34  that can store a plurality of the paper P to be used for recording on a lower side of the discharge tray  33  in a stacked state is mounted so as to be freely insertable in a front-back direction. 
     At a position on a front surface of the casing  22  illustrated in  FIG.  1    and an end portion side further in the left-right direction than the discharge port  32  (a right end portion side in  FIG.  1   ), an open/close door  35  that has a rectangular front surface and upper surface, and a right-angled triangle shaped right side surface is provided in a freely openable/closeable manner in the front-back direction centered about a rotation axis  36  provided on a lower end thereof and that extends in the left-right direction. A rectangular window portion  37  made of a transparent material is formed on a front surface of the open/close door  35 . A user is able to visually recognize the inside of the casing  22  (in particular, a rear side of the front surface of the open/close door  35 ) when the open/close door  35  is closed. 
     In the casing  22  of the recording device  21 , an ink refill unit  40  configured to refill ink to the recording head  25  is housed at a position on the rear side of the open/close door  35 , that is, a position closer to the front surface and an end portion of the open/close door  35  (closer to a right end portion in this case). The ink refill unit  40  is a structure that includes a plurality of (in this embodiment, five) ink tanks  41  to  45  and can be regarded as integral. As described later, each ink tank  41  to  45  is configured to be able to refill the ink. 
     The ink refill unit  40  illustrated in  FIG.  2    and  FIG.  3    is formed of the five ink tanks  41  to  45  that are substantially box-shaped and long in the front-back direction, five ink refill tubes  46  each drawn out from the rear side of each ink tank  41  to  45 , and a rectangular parallelepiped ink refill adapter  47  in which each of the ink tanks  41  to  45  are assembled as a group. Under a state in which all the ink tanks  41  to  45  are aligned side by side with a thickness direction as the left-right direction, the ink refill adapter  47  is assembled in a step portion  48  that is cut out in the upper front half portion of each of the ink tanks  41  to  45 , to thereby by integral with the ink tanks  41  to  45 . The ink refill tubes  46  drawn out from the ink tanks  41  to  45  illustrated in  FIG.  1    are connected to an ink flow passage (not shown) formed in the carriage  26 , and also the recording head  25  via the ink flow passage. The ink refill adapter  47  may form a part of the casing  22  that covers the ink tanks  41  to  45 , or may be formed integrally with the ink tanks  41  to  45 . 
     The ink tanks  41  to  45  illustrated in  FIGS.  4  and  5    each include an ink storage chamber  49  that can store an ink IK. In this embodiment, black ink is stored in the ink storage chamber  49  of the ink tank  41  that is located on a right end in a side-by-side direction. Ink of colors other than black (cyan, magenta, yellow, etc.) is stored in the ink storage chambers  49  of the other ink tanks  42  to  45  that are arranged further to the left than the ink tank  41  on the right side in the side-by-side direction. Visual recognition portions  50  formed of a transparent resin that allow a surface of the ink IK in the ink storage chamber  49  to be visually recognized are provided at front wall portions of the ink tanks  41  to  45  that can be visually recognized via the window portion  37  on the front surface of the casing  22 . An upper limit marker  51  that indicates an approximate upper limit of the surface of the ink IK stored in the ink storage chamber  49  (example of approximate ink amount that can be injected from the ink inlet  53  without overflowing), and a lower limit marking  52  that indicates an approximate lower limit (for example, an approximate amount for urging ink refill) is written on the visual recognition portion  50 . 
     In the ink tanks  41  to  45  illustrated in  FIG.  4   , an ink inlet  53  that allows the ink to externally flow into the ink storage chamber  49  is provided on an upper surface on a horizontal portion of the step portion  48 . The ink inlet  53  is formed of a needle  56  that extends vertically upward and includes flow passages  54 ,  55  that communicate the inside of the ink storage chamber  49  to the outside of the ink storage chamber  49 . The flow passages  54  and  55  of the needle  56  are formed of two flow passages  54  and  55  that are arranged side by side in a radial direction in which tip openings are centered about the needle  56 . One flow passage  54  (the right side in  FIG.  4   ) of the two flow passages  54  and  55  has a tip opening lower than that of the other flow passage  55  (the left side in  FIG.  4   ), and has a bigger cross-sectional area of the flow passage. A remaining ink sensor  57  for detecting a remaining quantity of ink IK in the ink storage chamber  49  is provided on a lower portion closer to the rear in the ink storage chamber  49 . The remaining ink sensor  57  may not be provided. 
     As illustrated in  FIGS.  2  to  5   , an upper surface  58  of the ink refill adapter  47  is a horizontal surface along a direction perpendicular to (that intersects) a direction in which the needle  56  extends, and a through hole  60  open in an up-down direction until a lower surface  59  is formed in the upper surface  58  as an ink inlet forming portion. The through hole  60  is formed of the circular hole-shaped ink inlet  53  in which the needle  56  is arranged in the center thereof, and a pair of front and rear rectangular portions that continue through the front and back of the ink inlet  53 , and an opening on a lower side of the through hole  60  is covered by a horizontal portion of the step portion  48  from which the needle  56  protrudes upward in the ink tanks  41  to  45 . 
     Therefore, in the through hole  60 , a pair of front and rear concave portions  61  that open on an upper side in the direction in which the needle  56  extends is formed with a vertical downward direction as a depth direction so as to be point symmetric with respect to the ink inlet  53  by the pair of front and rear rectangular portions that cover the opening on the lower side, in a region that forms an outer side of the ink inlet  53  in a radial direction centered about the ink inlet  53 . More specifically, a plurality of (in this case, a pair of front and rear) concave portions  61  that are point symmetrical around the ink inlet  53  are formed in a region that forms an outer side of the ink inlet  53  and includes the needle  56  in the ink refill adapter  47  integral with the ink tanks  41  to  45 . In this case, a tip of the needle  56  located at the center of the circular hole-shaped ink inlet  53  is located closer to the ink storage chamber  49  than the upper surface  58  of the ink refill adapter  47  is located to the ink storage chamber  49 . The ink refill adapter  47  forms an opening edge of the through hole  60  that includes the ink inlet  53  and the concave portion  61 . More specifically, the upper surface  58  of the ink refill adapter  47  extends in a direction that intersects with the direction in which the needle  56  extends at a position further outside than a tip of the needle  56  in the direction in which the needle  56  extends. On the other hand, the lower surface  59  of the ink refill adapter  47  functions as a tank engaging portion configured to engage with the plurality of ink tanks  41  to  45  arranged side by side in the left-right direction as a group from an upper side. 
     A peripheral portion of the opening edge on an upper side of the through hole  60  on the upper surface  58  of the ink refill adapter  47  is colored a specific color. More specifically, the peripheral portion is colored the same color as the ink stored in the ink storage chamber  49  of the ink tanks  41  to  45  to which the ink flows via the ink inlet  53  of the through hole  60 . In this respect, the peripheral portion of the opening edge on the upper side of the through hole  60  in the ink refill adapter  47  functions as a first portion that externally indicates information associated with the ink stored in the ink tanks  41  to  45  in which the ink inlet  53  of the through hole  60  communicates with the ink storage chamber  49 . Incidentally, the periphery portion of the upper end opening of the through hole  60  in which the ink inlet  53  that communicates with the ink storage chamber  49  of the ink tank  41  that stores the black ink is colored black. 
     On an inner surface (more specifically, an inner side surface along an up-down direction) of the concave portion  61 , a first concave/convex portion (first key structure portion)  62  that has a characteristically concave/convex shape in the horizontal direction is provided so as to extend along a depth direction (in other words, a central axis direction of the ink inlet  53 ) at a position in the concave portion  61  that is closer to a bottom surface (more specifically, a horizontal portion side of the step portion  48 )than the opening end of the upper surface is to the bottom surface. The first concave/convex portion  62  illustrated in  FIGS.  2  and  3    is provided for each ink inlet  53  of the plurality (in this embodiment, five) ink tanks  41  to  45 . Therefore, in the ink refill adapter  47 , in the rectangular concave portion  61  in the through hole  60  formed at a position that corresponds to each of the ink tanks  41  to  45  in the up-down direction, a first concave/convex portion  62  different to the first concave/convex portion  62  provided on the inner surface of the concave portion  61  of another through hole  60  is formed in each through hole  60 . More specifically, these first concave/convex portions  62  function as identification portions that make it possible to identify the ink refill container  63  (see  FIG.  6    and the like) that includes the ink outlet  65  (see  FIG.  6    and the like) connected to the ink inlet  53  in the through hole  60  in which the first concave/convex portion  62  is formed. A “position in the concave portion  61  that is closer to a bottom surface than the opening edge of the upper surface is to the bottom surface” means any position that is slightly further back toward the bottom surface than the opening edge. 
     Next, the ink refill container  63  that forms the ink refill system with the ink tanks  41  to  45  and refills the ink to the ink tanks  41  to  45  when the remaining ink quantity is low is described. 
     The ink refill container  63  illustrated in  FIGS.  6  to  8    includes a tubular container main body  64  that serves as the main part of the ink refill container  63 , an ink outlet-forming portion  66  provided at a tip portion of the container main body  64 , in which an ink outlet  65  configured to allow the ink to flow out from the ink refill container  63  is formed so as to be open at the top, and a container appendage  67  added to the ink outlet-forming portion  66  so as to surround the ink outlet  65 . The ink outlet  65  in the ink outlet-forming portion  66  is covered by a bottomed tubular cap  68  in addition to the container appendage  67  in the periphery thereof, to thereby shield the ink outlet  65  from the outside when the ink refill container  63  is stored. More specifically, a male threaded portion  69  is formed on an outer peripheral surface on a tubular lower end portion of the container appendage  67 , and a female threaded portion (not shown) is formed on an inner peripheral surface of the cap  68 . The female threaded portion in the cap  68  is threaded onto the male threaded portion  69  of the container appendage  67 , to thereby attach the cap  68  to the tip of the ink refill container  63  so as to cover the ink outlet  65 . 
     The entire outer surface of the container appendage  67  is colored a specific color. More specifically, the container appendage  67  is colored the same color as the ink that is stored in the container main body  64  to be added. In this regard, the container appendage  67  in the ink refill container  63  functions as a second portion that externally indicates information associated with the ink stored in the ink refill container  63 . Incidentally, the outer surface of the container appendage  67  in the ink refill container  63  that stores the black ink is colored black. In addition, a plurality of (in this embodiment, four) protrusions  70  are formed on outer peripheral surfaces of each of base end portions of the container main body  64  and the cap  68  at equal intervals (at 90° intervals, for example). Incidentally, these protrusions  70  are formed so as to prevent the tubular ink refill container  63  from rolling. In addition, for example, the container main body  64  of the ink refill container  63  that stores the black ink may be formed thicker than the container main body  64  of the ink refill container  63  that stores ink of another color. In this case, the ink outlet-forming portion  66  may be formed of thicknesses and shapes common for black ink and ink of other colors. 
     As illustrated in  FIGS.  6  to  8   , a convex portion  71  that protrudes further upward, which is a direction opposite to the container main body  64 , than the ink outlet  65  in a central axis direction of the ink outlet  65  is formed in a region that forms an outer side of the ink outlet  65  in a radial direction centered about the ink outlet  65  in a portion higher than a tubular lower end portion formed with the male threaded portion  69  on the outer peripheral surface of the container appendage  67 . When a tip of the needle  56  is inserted into the ink outlet  65 , the convex portion  71  functions as a second fitting portion which can be fitted with the concave portion  61  of the upper surface  58  of the ink refill adapter  47  as the first fitting portion, and is provided so as to form a pair that sandwiches the ink outlet  65  from the front to the rear similarly to the pair of concave portions  61  sandwiching the ink inlet  53  from the front to the rear. As illustrated in  FIGS.  6  and  7   , the convex portions  71  are formed further inward than the outer peripheral surface of the container main body  64  in the radial direction centered about the ink outlet  65  in the ink refill container  63 . 
     As illustrated in  FIGS.  6  and  9   , second concave/convex portions (second key structure portion)  72  that can engage with the first concave/convex portions (first key structure portion)  62  formed on the inner surface of the concave portion  61  of the ink refill adapter  47  are formed on outer surfaces (left and right side surfaces in  FIGS.  6  and  9   ) of each of the convex portions  71 . The second concave/convex portions  72  are provided so as to extend along a direction in which the convex portions  71  protrude (in other words, a central axis direction of the ink outlet  65 ), and cause the convex portion  71  to fit into the concave portion  61 . In addition, when the second concave/convex portions  72  are engaged with the first concave/convex portions  62 , the second concave/convex portions  72  connect the ink outlet  65  of the ink refill container  63  to the ink inlets  53  of the ink tanks  41  to  45 . 
     A flat positioning portion  73  that is perpendicular to (intersects) the central axis of the ink outlet  65  is provided between a tubular lower end portion formed with the male threaded portion  69  of the container appendage  67  and the convex portion  71  formed with the second concave/convex portion  72  so as to be located radially outward of the ink outlet  65  when the ink outlet  65  is viewed in the direction of its central axis. More specifically, the positioning portion  73  forms a part of the outer surface of the container appendage  67 , which is a part of the outer surface of the ink refill container  63 , and is located at a position closer to the container main body  64  than a tip of the convex portion  71  is located to the container main body  64  in the central axis direction of the ink outlet  65 . Because the positioning portion  73  is provided in the container appendage  67  added to the ink outlet-forming portion  66  in the ink refill container  63 , the positioning portion  73  is configured as a separate member to the ink outlet-forming portion  66 , and can be regarded as having a configuration provided on the outer side of the ink outlet-forming portion  66 . 
     As illustrated in  FIG.  9   , in the ink outlet  65  formed in the ink outlet-forming portion  66 , a valve  74  made of an elastic member such as a silicon film is provided to seal the ink outlet  65  in an openable manner. The valve  74  is provided at such a position that the positioning portion  73  is closer to the container main body  64  than the valve  74  is to the container main body  64  in the central axis direction of the ink outlet  65  (see  FIG.  14   , for example). The valve  74  is provided with a plurality of (in this embodiment, three) slits  75  that intersect at equal angular intervals (for example,  120 ° intervals) with their centers as intersection points, and these slits  75  are configured so as to open when pushed from outside the ink outlet  65 . More specifically, when the tip of the needle  56  on the ink inlet  53  side is inserted into the ink outlet  65 , the normally closed valve  74  opens by being pushed inward by the tip of the needle  56 . 
     At this time, the positioning portion  73  on the outer side of the ink outlet  65  in the radial direction abuts against the upper surface  58  of the ink refill adapter  47  formed with the through hole  60  that includes the ink inlet  53  and the concave portion  61 , to thereby position the valve  74  with respect to the ink tanks  41  to  45  in the central axis direction of the ink outlet  65 . In this regard, the upper surface  58  of the ink refill adapter  47  corresponds to a part of the ink tanks  41  to  45  on which the positioning portion  73  of the ink refill container  63  abuts when the valve  74  of the ink outlet  65  of the ink refill container  63  for refilling the ink to the ink tanks  41  to  45  opens, and functions as a receiving surface for receiving the flat positioning portion  73 . 
     The valve  74  may be formed as illustrated in  FIGS.  38  and  39   . As illustrated in  FIG.  38   , the valve  74  and a holder  102  are provided in the ink outlet-forming portion  66 . The valve  74  seals the ink outlet  65  in an openable manner. In the ink outlet-forming portion  66 , the valve  74  is provided in an outflow passage  93 , and the ink outlet  65  is sealed from within the outflow passage  93  in an openable manner. The valve  74  is formed of an elastic material such as rubber or an elastomer, and seals the ink outlet  65  under a state in which external force does not act on the valve  74 . The valve  74  opens when a connection conduit (needle  56 ) in the ink tanks  41  to  45  is inserted into the ink outlet  65 , and pressing force acts on the valve  74  due to the connection conduit  56 . Then, the valve  74  closes when the connection conduit (needle  56 ) is removed from the ink outlet  65  and the external force acting on the valve  74  is released. 
     As illustrated in  FIG.  39   , the valve  74  and the holder  102  are configured so as to be separated from the ink outlet-forming portion  66 . In other words, the ink outlet-forming portion  66 , the valve  74 , and the holder  102  are configured with separate members from one another. The valve  74  is inserted into the outflow passage  93  from a joining portion  91  of the ink outlet-forming portion  66 . The holder  102  is a component for restricting the valve  74  from falling and, as illustrated in  FIG.  38   , is provided on a joining portion  91  side of the valve  74 . The holder  102  is also inserted into the outflow passage  93  from the joining portion  91  side of the ink outlet-forming portion  66 . The valve  74  is sandwiched by the holder  102  and a flange portion  103  of the ink outlet-forming portion  66 . With this configuration, the ink outlet-forming portion  66 , the valve  74 , and the holder  102  are assembled integrally. The flange portion  103  is a wall that extends in an inner radial direction of a tubular portion  92  from an internal side surface of the tubular portion  92 . A surface on a side opposite to the joining portion  91  of the flange portion  103  corresponds to an edge surface  94 . 
     As illustrated in  FIGS.  10  and  11   , the container main body  64  in the ink refill container  63  is a bottle-shaped member that includes the ink storage chamber  76  that can store the ink IK, and the male threaded portion  78  is formed on an outer peripheral surface of a neck portion  77  on an upper end portion of the container main body  64 . The ink outlet-forming portion  66  provided on the upper end portion of the container main body  64  includes a large-diameter portion  79  located on an outer peripheral side of the neck portion  77  of the container main body  64 , a small-diameter portion  80  that forms the ink outlet  65  at a position furthest away from the container main body  64 , and an intermediate portion  81  that connects the large-diameter portion  79  and the small-diameter portion  80 . The female threaded portion  82  formed on an inner peripheral surface of the large-diameter portion  79  is threaded into the male threaded portion  78  formed on the outer peripheral surface of the neck portion  77  of the container main body  64 , to thereby mount the ink outlet-forming portion  66  to an upper end portion of the container main body  64 . 
     On the container appendage  67  added to the ink outlet-forming portion  66  in the ink refill container  63  so as to surround the ink outlet  65 , a tubular lower end portion formed with the male threaded portion  69  on the outer peripheral surface forms a junction  83  that joins a lower end surface of the container appendage  67  to an upper end surface of the large-diameter portion  79  of the ink outlet-forming portion  66 . The surface area of the inner circumferential surface of the joining portion  83  facing in the front-rear direction is in surface contact with the outer surface on the front side and the outer surface on the rear side of the intermediate portion  81  of the ink outlet forming portion  66 , so as to be joined to the large-diameter portion  79  of the ink outlet forming portion  66 . 
     Next, operation of the ink refill system configured as described above is described, focusing on operation when ink is refilled to the ink tanks  41  to  45  in the ink refill unit  40  using the ink refill container  63 . 
     As a prerequisite, as illustrated in  FIG.  2   , because the surface height of the ink in the ink tank  41  for black ink located furthest to the right among the plurality of ink tanks  41  to  45  arranged side by side has fallen to the height of the lower limit marker  52  written on the lower portion of the visual recognition portion  50 , a case in which the ink is refilled to the ink tank  41  is described below. In addition, it is assumed that enough black ink is stored in the ink refill container  63  used to refill the ink, and that the cap  68  has already been removed from the ink refill container  63 . It is also assumed that the shape of the second concave/convex portion  72  formed on the outer surface of the convex portion  71  of the ink refill container  63  matches the shape of the first concave/convex portion  62  formed on the inner surface of the concave portion  61  located front and back of the ink inlet  53  of the ink tank  41 , and that these concave/convex portions can be engaged by the convex portion  71  being inserted into the concave portion  61 . 
     When the ink is refilled to the ink tank  41 , the user first changes the state of the open/close door  35  of the casing  22  from the closed state illustrated in  FIG.  1    to an open state by rotating the open/close door  35  to the front about the rotation axis  36 . Then, in the ink refill unit  40 , the upper surface  58  of the ink refill adapter  47  formed with the ink inlet  53  of the ink tanks  41  to  45  is exposed to the outside of the casing  22 , and the user can connect the ink outlet  65  of the ink refill container  63  to the desired ink inlet  53  from above. 
     Then, as illustrated in  FIGS.  12  and  13   , the user turns the ink refill container  63  that stores the black ink to be used for ink refill upside down, and holds the ink refill container  63  so that the ink outlet  65  is located above the through hole  60  on the further right side of the ink refill adapter  47 . More specifically, a central axis line of the ink outlet  65  of the ink refill container  63  is matched with a central axis line of the ink inlet  53  of the ink tank  41  of the ink to be refilled. At this time, the user compares the color (second portion) of the container appendage  67  of the ink refill container  63  that the user is holding, and the color (first portion) around the opening edge on the upper side of the through hole  60  provided with the ink inlet  53  of the ink tank  41  of the ink to be refilled at that time. Then, if the two colors are the same (in this case, both black), the user checks that they are holding the appropriate ink refill container  63  for the ink refill this time, and proceeds to subsequent operations for the ink refill. 
     Then, the user lowers ink refill container  63  from the state illustrated in  FIGS.  12  and  13   , and inserts the convex portion  71  of that ink refill container  63  into the concave portion  61  of the ink refill adapter  47  integral with the ink tank  41 . Then, by realizing insertion of the convex portion  71  to the concave portion  61 , the matching state of the central axis line of the ink outlet  65  with respect to the central axis line of the ink inlet  53  is secured. In this case, because the concave portion  61  is located at a position point symmetrical to the needle  56 , which is at the center of the ink inlet  53 , the convex portion  71  can be inserted into any concave portion  61 . Therefore, there is no need to check the appropriate positional relationship between the concave portion  61  and the convex portion  71  by repeatedly rotating the ink refill container  63  about the center axis line of the ink outlet  65 , and the user can easily insert the convex portion  71  into the concave portion  61 . 
     However, at this time, although the tip of the needle  56  located at the center of the ink inlet  53  is also inserted into the opening of the ink outlet  65  that protrudes slightly from the tip of the convex portion  71  by the convex portion  71  being slightly inserted into the concave portion  61 , the tip does not reach the valve  74  located deep inside the ink outlet  65 . The reason for this is as follows. As illustrated in  FIG.  13   , a distance L 2  between the tip of the convex portion  71  and the valve  74  in the ink outlet  65  is longer than a distance L 1  between the upper surface  58  of the ink refill adapter  47  where the opening edge of the concave portion  61  is located and the upper end of the first concave/convex portion  62  in the concave portion  61 . As a result, when the convex portion  71  is further inserted downward in the depth direction of the concave portion  61  from that state, the second concave/convex portion  72  on the outer surface of the convex portion  71  engages with the first concave/convex portion  62  on the inner surface of the concave portion  61 . Then, when the convex portion  71  is further inserted into toward the bottom surface side in the depth direction of the concave portion  61  while maintaining that engagement state, the top of the needle  56  of the ink inlet  53  reaches the position of the valve  74  of the ink outlet  65 , and the valve  74  opens. 
     More specifically, as illustrated in  FIGS.  14  and  15   , the tip of the needle  56  pushes the slit  75  upward (that is, inward from the ink outlet  65 ) from the valve  74 , to thereby change the valve  74  to the open state. As a result, the ink outlet  65  of the ink refill container  63  and the needle  56  of the ink inlet  53  of the ink tank  41  become connected, and the black ink is refilled to the ink tank  41  from the ink refill container  63 . As this time, one of the two flow passages  54  and  55  in which the tip opening first touches the ink flowing out from the ink outlet  65  by the needle  56  of the ink inlet  53  opening the valve  74  functions as an ink flow path through which ink flows, and the other flow passage functions as an air flow passage for circulating air. For example, when the user tries to connect the ink outlet  65  to the ink inlet  53  while the ink refill container  63  is inclined, the flow passage as the ink flow passage among the two flow passages  54  and  55  changes depending on a different of the direction of inclination. 
     If the second concave/convex portion  72  is not engaged with the first concave/convex portion  62  after the convex portion  71  has been inserted into the concave portion  61 , at that time, the user can recognize that they are trying to incorrectly insert an ink refill container  63  of a color other than black. In this case, if an upper end of the first concave/convex portion  62  is located at the same height as the opening edge of the concave portion  61 , engagement of the second concave/convex portion  72  to the first concave/convex portion  62  is rejected, and insertion of the convex portion  71  to the concave portion  61  is also rejected. Therefore, the user may try to insert the convex portion  71  into the concave portion  61  many times and waste time performing a useless action. In this regard, in this embodiment, the height of the first concave/convex portion  62  is lower than that of the opening edge of the concave portion  61 , and hence the convex portion  71  can be easily guided to the bottom surface side of the concave portion  61  in the depth direction when being inserted to the concave portion  61 , and operation time is not wastefully long. 
     In addition, as illustrated in  FIGS.  14 ,  16  and  17   , when the valve  74  in the ink outlet  65  of the ink refill container  63  is opened by the needle  56  of the ink inlet  53  on the ink tank  41  side, the positioning portion  73  in the ink refill container  63  abuts against the upper surface  58  of the ink refill adapter  47 , which is a part of the ink tank  41  side. More specifically, the positioning portion  73  in the ink refill container  63  abuts against the upper surface  58  of the ink refill adapter  47 , to thereby open the valve  74  under a state in which the valve  74  is positioned in the central axis direction of the ink outlet  65  with respect to the needle  56  on the ink tank  41  side. 
     At that time, because the positioning portion  73  is located radially outward of the ink outlet  65 , the orientation of the ink refill container  63  in which the ink outlet  65  is connected to the ink inlet  53  can be stably maintained. In addition, as illustrated in  FIGS.  14  and  15   , when the positioning portion  73  of the ink refill container  63  abuts against the upper surface  58  of the ink refill adapter  47 , a gap exists between a bottom surface of the ink inlet  53  where the base end of the needle  56  in the ink inlet  53  is located, and a tip of the ink outlet  65  of the ink refill container  63 . Therefore, ink easily collects on the bottom surface of the ink inlet  53  where the base end of the needle  56  in the ink inlet  53  is located, but the collected ink can be prevented from adhering to the tip of the ink outlet  65  and contaminating the ink refill container  63 . 
     As illustrated in  FIGS.  14  and  16   , when the ink refill to the ink tank  41  from the ink refill container  63  is complete, if the surface height of the ink in the ink tank  41  is still lower than the upper limit marker  51  of the visual recognition portion  50 , ink refill may be performed again using another black ink refill container  63  until the surface reaches the upper limit marker  51 . The above-described ink refill operation is similarly performed for the ink tanks  42  to  45  of colors different to that of the ink tank  41  for black ink. 
     According to the Above-Described First Embodiment, the Following Effects Can be Achieved. 
     (1) During the ink refill to the ink tanks  41  to  45  from the ink refill container  63 , the valve  74  is opened while being positioned with respect to the ink tanks  41  to  45 . Therefore, ink spillage and incorrect ink refilling that may occur when the valve  74  displaces when the valve  74  opens can be suppressed, and the ink can be appropriately refilled to the ink tanks  41  to  45 . 
     (2) Because the valve  74  is configured as a slit valve provided with the one or more slits  75  in an elastic member such as a silicon film, the ink refill container  63  can be provided with few components and a simple structure. 
     (3) Because the positioning portion  73  in the ink refill container  63  abuts against part of the ink tanks  41  to  45  while being located radially outward of the ink outlet  65  when the ink is refilled to the ink tanks  41  to  45  from the ink refill container  63 , the ink can be refilled at a stable orientation. 
     (4) Because the positioning portion  73  in the ink refill container  63  is provided to the container appendage  67  as a member separate to the ink outlet-forming portion  66 , the positioning portion  73  can be optimized in accordance with design specifications of the ink tanks  41  to  45  and the ink refill container  63 . 
     (5) When the needle  56  of the ink tanks  41  to  45  in the ink outlet  65  of the ink refill container  63  is inserted into the valve  74  to open the valve  74 , the positioning portion  73  of the ink refill container  63  abuts against the upper surface  58  of the ink refill adapter  47  that functions as a receiving surface of the ink refill container  63  in the ink tanks  41  to  45  to determine the relative positional relationship between the valve  74  and the needle  56 . Therefore, the valve  74  can be appropriately opened by the needle  56 , and the occurrence of incorrect ink refilling can be suppressed. 
     (6) When the ink is refilled, because the needle  56  is not inserted into the ink outlet  65  if the convex portion  71  of the ink refill container  63  is not fitted into the concave portion  61  of the ink tanks  41  to  45 , inappropriate connection between the ink tanks  41  to  45  and the ink refill container  63  can be suppressed. 
     (7) The ink refill container  63  includes the positioning portion  73  on an outer side of the ink outlet-forming portion  66  at a position closer to the container main body  64  than the convex portion  71  is to the container main body  64  in the central axis direction of the ink outlet  65 . Therefore, inappropriate connection between the ink tanks  41  to  45  and the ink refill container  63  can be suppressed, and the insertion of the needle  56  of the ink tanks  41  to  45  to the ink outlet  65  of the ink refill container  63  can be guaranteed at an appropriate position. 
     (8) Because the tip of the needle  56  of the ink tanks  41  to  45  does not protrude further outward than the upper surface  58  of the ink refill adapter  47  that acts as the receiving surface of the positioning portion  73  of the ink refill container  63 , even if ink adheres to the tip of the needle  56 , the risk of that ink adhering to the hand of a user who performs the ink refill, or the ink refill container  63  can be reduced. 
     (9) When connection is performed from the direction in which the needle  56  extends from the ink tanks  41  to  45  with the ink refill container  63  in a state inclined along a radial direction in which the two flow passages  54  and  55  are arranged, one of the two flow passages  54 ,  55  on a side on which the ink outlet  65  of the ink refill container  63  first approaches acts as an ink flow passage, and the other flow passage acts as an air flow passage. Therefore, because the user may use either of the two flow passages  54  and  55  as the ink flow passage, the user can quickly refill the ink without hesitating in choosing the flow passage to be the ink flow passage. 
     (10) Through fitting the convex portion  71  of the ink refill container  63  into the concave portion  61  of the ink tanks  41  to  45 , and engaging the second concave/convex portion  72  on the outer surface of the convex portion  71  with the first concave/convex portion  62  on the inner surface of the concave portion  61 , the user can recognize that the appropriate ink refill container  63  has been connected to the ink tanks  41  to  45 . As a result, inappropriate connection between the ink tanks  41  to  45  and the ink refill container  63  can be suppressed. In addition, because the first concave/convex portion  62  is closer to the bottom than the opening edge of the concave portion  61  is to the bottom inside of the concave portion  61  of the ink tanks  41  to  45 , the convex portion  71  in the ink refill container  63  can be easily guided to the bottom from the opening of the concave portion  61  in the ink tanks  41  to  45 , and insertion can be made easily. 
     (11) The second concave/convex portion  72  (second key structure portion) on the outer surface of the convex portion  71  in the ink refill container  63  can be engaged with the first concave/convex portion (first key structure portion)  62  provided so as to extend along the depth direction of the concave portion  61  on the inner surface of the concave portion  61  of the ink tanks  41  to  45  by making the convex portion  71  fit into the concave portion  61 . As a result, the connection direction of the ink outlet  65  of the ink refill container  63  to the ink inlet  53  of the ink tanks  41  to  45  can be easily recognized. 
     (12) Because the depth direction of the concave portion  61  provided radially outward of the ink inlet  53  is a direction that faces vertically downward, the ink can be prevented from returning to the ink storage chamber  76  from the ink outlet  65  of the ink refill container  63  under a state in which the ink outlet  65  of the ink refill container  63  is connected to the ink inlet  53  of the ink tanks  41  to  45 . As a result, the ink can be appropriately refilled to the ink tanks  41  to  45  from the ink refill container  63 . 
     (13) Even when the convex portion (second fitting portion)  71  of the ink refill container  63  is fitted into any of the plurality of concave portions (first fitting portions)  61  formed point symmetrical about the ink inlet  53  in the ink tanks  41  to  45 , the ink outlet  65  of the ink refill container  63  can be connected to the ink inlet  53  of the ink tanks  41  to  45 . Therefore, it is easy to connect to the ink tanks  41  to  45  of the ink refill container  63  when the ink is refilled. 
     (14) The color of the peripheral portion of the ink inlet  53  of the ink refill adapter  47  in the ink tanks  41  to  45  functions as the first portion for indicating information associated with the ink stored in the ink storage chamber  49 , and the color of the container appendage  67  of the ink refill container  63  functions as the second portion for indicating information associated with the ink stored in the ink storage chamber  76 . Therefore, when the ink is refilled by connecting the ink refill container  63  to the ink tanks  41  to  45 , whether or not the ink to be refilled is appropriate can be easily checked by visually confirming the first portion on the ink tank  41  to  45  side and the second portion on the ink refill container  63  side. 
     (15) Because the ink refill container  63  is formed further inward than the outer peripheral surface of the container main body  64  provided with the ink storage chamber  76  in the radial direction in which the convex portions  71  are centered about the ink outlet  65 , the convex portions  71  of the ink refill container  63  are less likely to become a hindrance when the ink outlet  65  of the ink refill container  63  is connected to the ink inlet  53  of the ink tanks  41  to  45 . 
     (16) The ink refill adapter  47  includes the plurality of first concave/convex portions (identification portions)  62  that make it possible to identify the ink refill container  63  containing the ink outlet  65  that can connect to the ink inlet  53  of every ink tank  41  to  45  when the ink refill adapter  47  engages the lower surface (tank engaging portion)  59  with the plurality of ink tanks  41  to  45  as a group. Therefore, if the ink tanks  41  to  45  have a general common structure, and the lower surface  59  as the tank engaging portion of the ink refill adapter  47  is engaged with the plurality of ink tanks  41  to  45  as a group, a simple structure that can suppress incorrectly mounting the ink refill container  63  when the ink is refilled can be obtained. 
     Second Embodiment 
     Next, a second embodiment of a recording device is described with reference to the drawings. Positioning of the ink tank and the ink refill adapter in the second embodiment differs from that in the first embodiment. Other aspects are substantially the same as those in the first embodiment, and hence redundant description is omitted by denoting like configurations with like reference symbols. 
     As illustrated in  FIG.  18   , a multi-function printer  14  includes the recording device  21 , and an image reading device  15  located on the recording device  21  so as to cover an upper side of the recording device  21 , and has a substantially rectangular parallelepiped shape overall. On a front side (front surface side) of the recording device  21 , there is provided an operation panel  18  including operation buttons  16  for performing various operations of the multi-function printer  14 , and a display unit  17  for displaying information on the recording device  21  and the multi-function printer  14  and the like. The ink refill unit  40  is provided on a right side of the operation panel  18 . 
     As illustrated in  FIG.  19   , the image reading device  15  is mounted via a rotating mechanism  19  such as a hinge provided on a rear side (rear surface side) of the image reading device  15 . The image reading device  15  can be opened/closed with respect to the recording device  21 , and rotates between the closed position illustrated in  FIG.  18    and the open position illustrated in  FIG.  19   . When the image reading device  15  is moved to the open position, a unit cover  100  and an elastic cap  92  of the ink refill unit  40  can be opened/closed. As illustrated in  FIG.  19   , when ink is refilled to the ink tanks  41  to  45  (see  FIG.  20   ), the image reading device  15 , the unit cover  100 , and the elastic cap  92  are moved to the open position, and the ink refill container  63  is connected to the ink refill adapter  47  and ink tanks  41  to  45 . More specifically, the ink refill adapter  47  is mounted so as to be located on the ink tanks  41  to  45  under a state in which the ink is refilled to the ink tanks  41  to  45  from the ink refill container  63 . In other words, the ink refill adapter  47  connects the ink refill container  63  and the ink tanks  41  to  45  when the ink is refilled to the ink tanks  41  to  45  from the ink refill container  63 . 
     As illustrated in  FIG.  20   , two types of ink tanks  41  to  45  having different storable ink quantities are arranged side by side with a thickness direction thereof as a left-right direction in the ink refill unit  40 . 
     The ink tank  41 , which has a large storage quantity, and the ink tanks  42  to  45 , which each have a small storage quantity, have different thicknesses, but have the same structure. Therefore, common configurations in the ink tanks  41  to  45  are denoted by the same reference symbols, and redundant descriptions thereof are omitted. 
     The needle  56  is formed so as to protrude upward from a top surface  111  of the ink tanks  41  to  45 . A side surface  112  on a visual confirmation unit  50  side (front side) that intersects with the top surface  111  is provided with a tank-side positioning portion  113  that protrudes forward. The tank-side positioning portions  113  of each of the ink tanks  41  to  45  are located at substantially the same position in the up-down direction, and intervals between tank-side positioning portions  113  between the adjacent ink tanks  41  to  45  are substantially the same. 
     An absorbing member  123  that has a substantially rectangular shape in plan view and that can absorb ink is provided on the top surface  111  of the ink tanks  41  to  45 . A plurality of (in this embodiment, six) round holes  123 a are formed in the absorbing member  123 . In the absorbing member  123 , each of the needles  56  are inserted through the round holes  123 a, and a part of a film  124  for sealing the opening of the ink tank  41  to  45  that extends further upward than the top surface  111  is folded and attached to the ink tank  41  to  45 . The absorbing member  123  may be such a size as to cover all of the top surface  111  (see  FIG.  28   ). 
     As illustrated in  FIGS.  21  and  22   , the tank-side positioning portion  113  includes a bottom wall  114  provided so as to extend from the side surface  112  at a position lower than the top surface  111 , and a pair of side walls  115  that stand erect from the bottom wall  114 . The tank-side positioning portion  113  is provided so as to open forward and upward. 
     On the top surface  111  of the ink tanks  41  to  45  at a position on a front end adjoined to the tank-side positioning portion  113 , a protruded portion  116  configured to support the ink refill adapter  47  is provided. The protruded portion  116  is also provided on a rear end of the top surface  111 . In other words, a pair of the protruded portions  116  is provided so as to sandwich the needle  56  at positions at either end of the top surface  111  in the front-back direction. 
     As illustrated in  FIG.  22   , a partition wall  117  that extends along the up-down direction at a center position in the front-back direction is formed in the cylindrical needle  56 . The flow passages  54  and  55  are divided by this partition wall  117 . Therefore, a height and cross-sectional area of tip end openings of the flow passages  54  and  55  according to this embodiment are formed substantially equal. In addition, the needle  56  is provided in the ink tanks  41  to  45  so as to allow the ink to flow into the ink storage chamber  49  provided in the ink tanks  41  to  45 . 
     Next, the ink refill adapter  47  is described. 
     As illustrated in  FIGS.  23  and  24   , the ink refill adapter  47  includes an inlet forming portion  119  that partially surrounds the needle  56 , which is an example of an ink inlet flow passage portion. A plurality of (in this embodiment, five, which is the same number as the ink tanks  41  to  45 ) inlet forming portions  119  are arranged side by side in the left-right direction on the upper surface  58  of the ink refill adapter  47 . The inlet forming portion  119  according to this embodiment is a concave portion with a bottom, and has substantially the same shape as the through hole  60  (see  FIG.  3   ) as seen in plan view. In addition, the ink refill adapter  47  includes a first concave/convex portion  62  as an example of an identification portion with which it is possible to identify the ink refill container  63  that has the ink outlet  65  that can be connected to the needle  56 . The first concave/convex portion  62  according to this embodiment is provided such that a convex portion stands erect from a bottom surface of the inlet forming portion  119 . 
     As illustrated in  FIG.  24   , an insertion hole  120  through which the needle  56  can be inserted is formed on the bottom surface of each of the inlet forming portions  119 . The diameter of the insertion hole  120  is larger than the diameter of the needle  56 , and a gap is provided between the needle  56  and the insertion hole  120 . Therefore, if ink spills on the ink refill container  63  or the needle  56 , the spilled ink is absorbed by the absorbing member  123  through the gap between the needle  56  and the insertion hole  120 . 
     As illustrated in  FIGS.  25  and  26   , an adapter-side positioning portion  121  configured to position the ink refill adapter  47  with respect to the ink tanks  41  to  45  is provided on the lower surface  59  of the ink refill adapter  47 . The adapter-side positioning portion  121  can be engaged with the tank-side positioning portion  113  provided in the ink tanks  41  to  45 , and a plurality of (in this embodiment, five, which is the same number as the ink tanks  41  to  45 ) adapter-side positioning portions  121  are arranged side by side in the left-right direction at a position further forward than the insert hole  120 . In addition, intervals between the plurality of adapter-side positioning portions  121  in the left-right direction is substantially equal to intervals between the tank-side positioning portion  113  in the left-right direction in the ink tanks  41  to  45 . 
     In addition, a pair of ribs  122  provided with intervals in-between in the front-back direction are provided in a plurality of (in this embodiment, five) groups in the left-right direction on the lower surface  59  of the ink refill adapter  47 . The interval between the pair of ribs  122  in the front-back direction is substantially the same as the size of the top surface  111  of the ink tanks  41  to  45 . One adapter-side positioning portion  121  and one rib  122  are provided on either ends of one insertion hole  120  in the left-right direction. More specifically, as illustrated in  FIG.  26   , an interval B between a center line A along the front-back direction through the center of the insertion hole  120  and the adapter-side positioning portion  121  is substantially equal to an interval C between the center line A and the rib  122 . Corners of the adapter-side positioning portion  121  and the rib  122  are chamfered. 
     As illustrated in  FIGS.  24  and  25   , in the ink refill adapter  47 , a plurality of the inlet forming portions  119 , a first concave/convex portion  62  that corresponds to the plurality of inlet forming portions  119 , a plurality of the adapter-side positioning portions  121 , and a plurality of groups of the ribs  122  are formed integrally. 
     Next, action of the ink refill adapter  47  configured as described above is described. 
     As illustrated in  FIGS.  27  and  28   , when the ink refill adapter  47  is attached to the ink tanks  41  to  45  so as to insert the needle  56  into the insertion hole  120  of the ink refill adapter  47 , the adapter-side positioning portion  121  engages with the tank-side positioning portion  113 . More specifically, the adapter-side positioning portion  121  is positioned in the left-right direction by being inserted between the side walls  115  of the tank-side positioning portion  113 . In addition, the ink refill adapter  47  is positioned in the front-back direction by the ribs  122  sandwiching the ink tanks  41  to  45  from both sides. The ink refill adapter  47  that has been positioned with respect to the ink tanks  41  to  45  is fixed to the casing  22  with a screw (not shown). 
     The absorbing member  123  provided between the ink refill adapter  47  and the top surface  111  of the ink tanks  41  to  45  may be provided to each ink tank  41  to  45 . In addition, the absorbing member  123  may be provided so as to extend from the top surface  111  of the ink tanks  41  to  45  to the side surface  112  (only a portion that corresponds to the ink tank  45  is illustrated in  FIG.  27   ). 
     According to the above-described second embodiment, the following effects can be achieved in addition to the effects (1) to (16) of the above-described first embodiment. 
     (17) Because the ink refill adapter  47  is positioned with respect to the ink tanks  41  to  45 , displacement between the needle  56  provided in the ink tanks  41  to  45  and the inlet forming portion  119  provided in the ink refill adapter  47  can be suppressed. Therefore, the ink can be appropriately refilled to the ink tanks  41  to  45  from the ink refill container  63  via the ink refill adapter  47 . 
     (18) Because the inlet forming portion  119 , the first concave/convex portion  62 , and the adapter-side positioning portion  121  are formed integrally, the ink refill adapter  47  can be manufactured with a simpler structure than if these components were provided separately. 
     The above-described embodiments may be modified as follows.
         As illustrated in  FIGS.  29  and  30   , in the ink refill container  63 , a tip of the convex portion  71  in the central axis direction of the ink outlet  65  may be configured to protrude more toward a side opposite to the container main body  64  than the ink outlet  65 . With this configuration, when the ink is refilled, because the convex portion  71  protrudes more than the ink outlet  65  in the ink refill container  63 , a risk of the ink outlet  65  touching the hand of the user or the periphery of the ink refill container  63  can be reduced, and contamination due to the ink adhering can be suppressed.   As illustrated in  FIG.  31   , if the ink refill container  63  includes the positioning portion  73  configured to partially abut against the ink tanks  41  to  45  when the ink is refilled to positon the valve with respect to the ink tanks  41  to  45  at a position closer to the container main body  64  than the valve  74  is to the container main body  64  in the central axis direction of the ink outlet  65 , the convex portion  71  does not need to be provided. In this case, the concave portion  61  also does not need to be provided to the ink tanks  41  to  45 .   According to a modification example illustrated in  FIG.  32   , the ink refill unit  40  may have a structure in which the ink inlet  53  is normally closed. More specifically, the ink refill unit  40  according to this modification example includes a lever-shaped cap supporting member  90  provided to each of the plurality of ink inlets  53 . A base end portion of the cap supporting member  90  is supported so as to be rotatable about the rotation axis  91  provided so as to extend in the direction (horizontal direction) that intersects the central axis of the ink inlet  53  in the upper surface  58  of the ink refill adapter  47 . A tip end side with respect to the center in a longitudinal direction of the cap supporting members  90  is provided with the elastic cap  92  having a shape that can fit into the ink inlet  53 , and the cap supporting member  90  is normally in a closed state in which this elastic cap  92  is fit into the ink inlet  53 . When the ink is refilled, the cap supporting member  90  in the closed state in which the elastic cap  92  is fit into the ink inlet  53  is tilted by a user who operates a handle portion  93  that has a bent tip to put the elastic cap  92  into an open state separated from the ink inlet  53 . As illustrated in  FIG.  32   , the unit cover  100  that covers the tops of the plurality of cap supporting members  90  as a group may further be provided so as to be openable/closeable. The elastic cap  92  may be made of, for example, an elastic material such as an elastomer, and the cap supporting member  90  may be made from a material stronger than the elastic cap  92 , for example, polyethylene or an ABS resin.   According to a modification example illustrated in  FIG.  33   , the ink refill adapter  47  may be mounted to the ink refill unit  40  so as to be movable relative to the ink tanks  41  to  44 . More specifically, the ink refill adapter  47  includes a fixed portion  125  fixed to the casing  22 , a displacement portion  126  that can become displaced from the ink tanks  41  to  44 , and a connection portion  127  that connects the fixed portion  125  and the displacement portion  126 . The connection portion  127  can deform, and the displacement portion  126  can become displaced in the direction that intersects the up-down direction in which the needle  56  extends. Therefore, the displacement portion  126  can displace under a state in which the ink refill container  63  is engaged with the inlet forming portion  119 , and relatively move the ink refill container  63  and the needle  56 . Therefore, because the ink outlet  65  of the ink refill container  63  and the needle  56  can be easily aligned, the risk of ink spillage can be reduced.   According to a modification example illustrated in  FIG.  34   , a groove portion  129  may be formed on the tip of the ink outlet  65 . In addition, at least one (in this embodiment, two) cyclic convex portion  130  may be formed between the tip of the ink outlet  65  and the positioning portion  73  so as to extend along the outer periphery of the small-diameter portion  80 . By providing the groove portion  129 , when the ink refill container  63  that has refilled the ink to the ink tanks  41  to  45  is made erect, the risk of ink leaking from the ink outlet  65  can be reduced. In addition, by providing the cyclic convex portions  130 , the ink can be held back even if the ink leaks from the ink outlet  65 .   According to a modification example illustrated in  FIG.  35   , the pair of convex portions  71  provided along a straight line D that passes through the center of the ink outlet  65  may be divided into a plurality of (in this embodiment, six) regions E, and the second concave/convex portion  72  may be formed of identification convex portions  132   a  to  132   c  provided in each of the regions E. In this modification example, the second concave/convex portion  72  is formed of three types of identification convex portions  132   a  to  132   c . More specifically, a first identification convex portion  132   a  having a long length from the straight line D to the side surface of the convex portion  71 , a second identification convex portion  132   b  that is shorter than the first identification convex portion  132   a , and a third identification convex portion  132   c  shorter than the second identification convex portion  132   b  may be combined as needed to form the second concave/convex portion  72 . The number of regions E and the number of types of identification convex portions  132   a  to  132   c  can be increased to increase patterns on the second concave/convex portion  72  and correspond to the amount and type of ink.   According to a modification example illustrated in  FIG.  36   , the small-diameter portion  80  may be made of a transparent or translucent material. In addition, a surface on an inner side of the small-diameter portion  80  extending toward the ink storage chamber  76  from the valve  74  may be a rough surface  80   a  provided with uneveness through, for example, grinding. The rough surface  80   a  can make it easier to identify the color of ink from outside the small-diameter portion  80  because the rough surface  80   a  has high wettability and ink easily remains on the rough surface  80   a.      According to a modification example illustrated in  FIGS.  36  and  37   , the cap  68  is attached to the ink refill container  63  so as to make contact with an attachment surface  134  of the ink refill container  63 , and is in a state of being attached. In addition, in the state of being attached, the cap  68  includes an annular sealing portion  135  configured to seal the ink outlet  65 . An inner surface  135   a  of the sealing portion  135  is obliquely formed so as to widen toward the tip. In the state of being attached, the cap  68  seals the ink outlet  65  by the inner surface  135   a  making contact with a corner  136  of the ink outlet  65 . Therefore, even when the cap  68  is lightly engaged with and attached to the attachment surface  134 , the contact between the inner surface  135   a  and the corner  136  can reduce the risk of the ink spilling from the ink outlet  65 . The corner  136  may be a portion at which two surfaces facing in different directions intersect, or may be curved.   Among the first concave/convex portion  62 , the adapter-side positioning portion  121 , and the rib  122  in the ink refill adapter  47 , at least one component may be formed separately. Among the ribs  122  provided in on both the front and rear sides, the rib  122  on the front side may not be provided. At least one rib  122  may be provided on the rear side, and the ink refill adapter  47  may be positioned in the front-back direction by the rib  122  on the rear side and the adapter-side positioning portion  121 . In addition, the rib  122  may not be provided.   If the tank-side positioning portion  113  and the adapter-side positioning portion  121  can be engaged with each other to position the ink refill adapter  47  to the ink tanks  41  to  45 , the shapes of those components may be changed as needed. For example, the tank-side positioning portion  113  may be a step portion formed around the needle  56 , and the adapter-side positioning portion  121  may be a concave portion that surrounds the step portion, or a hole. By providing the tank-side positioning portion  113  and the adapter-side positioning portion  121  at a position close to the needle  56 , positional accuracy of the inlet forming portion  119  with respect to the needle  56  can be increased.   The ink refill container  63  may protrude further outward than the outer peripheral surface of the container main body  64  provided with the ink storage chamber  76  in the radial direction in which the convex portions  71  are centered about the ink outlet  65 . With this configuration, the user can easily visually recognize the convex portions  71  when viewing the ink refill container  63 , and the convex portion  71  of the ink refill container  63  can be more easily fitted into the concave portion  61  of the ink tanks  41  to  45  when the ink is refilled. As a result, incorrect connection of the ink refill container  63  to the ink tanks  41  to  45  can be reduced.   The first portion provided to each of the ink tanks  41  to  45  as a portion that indicates information associated with the ink stored in the ink tanks  41  to  45 , and the second portion provided to each of the ink refill containers  63  as a portion that indicates information associated with the ink stored in the ink refill containers  63  may be information other than color information, such as text information or shape information. In addition, the first portion and the second portion may not be provided.   If the plurality of concave portions  61  is provided on the ink tank  41  to  45  side, the convex portions  71  on the ink refill container  63  side may have a single configuration. In addition, if there is a plurality of concave portions  61 , the plurality of concave portions  61  do not necessarily have to be arranged point symmetrical about the center of the ink inlet  53 .   If the plurality of concave portions  61  on the ink tank  41  to  45  side are provided at a point symmetrical position, in addition to the pair of concave portions  61  symmetrical at 180°, a plurality of point symmetric arrangement configurations may be used, such as three at 120° point symmetry, and four at 90° point symmetry.   Among the ink concave portions  61  and the convex portions  71  that are engaged when the ink is refilled, a convex portion  71  may be provided to the ink tank  41  to  45  side as a first fitting portion, and a concave portion  61  may be provided to the ink refill container  63  side as a second fitting portion.   If the depth direction of the concave portion  61  on the ink tank  41  to  45  sides follows the direction in which the needle  56  located at the center of the ink inlet  53  extends, the depth direction does not necessarily need to be a vertical direction, and may be a direction that intersects a perpendicular direction. However, in order to suppress ink leakage, a direction along a horizontal direction is not preferable as the depth direction of the concave portion  61 .   The height of the tip of the first concave/convex portion  62  on the inner surface of the concave portion  61  may be equal to or more than a height of the opening edge of the concave portion  61 .   If the identification portion with which it is possible to identify the ink refill container  63  having the ink outlet  65  that can connect to the ink inlet  53  of the ink tank  41  to  45  is provided separately, the first concave/convex portion  62  on the inner surface of the concave portion  61  and the second concave/convex portion  72  on the outer surface of the convex portion  71  need not necessarily be provided.   The two flow passages  54  and  55  that include the needle  56  of the ink inlet  53  may have both tip openings that are the same height, or a plurality of flow passages other than two may be provided.   In the ink refill container  63 , the convex portion  71  and the positioning portion  73  may be directly formed in the ink outlet-forming portion  66  instead of in the container appendage  67  that is added to the ink outlet-forming portion  66 . More specifically, the container appendage  67  may not be added to the ink outlet-forming portion  66 , and may be formed integrally with the ink outlet-forming portion  66 .   If the positioning portion  73  in the ink refill container  63  is in the region that forms an outer edge of ink outlet  65  in the radial direction centered about the ink outlet  65 , the positioning portion  73  may be provided outside the radial direction and not outside the plurality of radial directions centered on the ink outlet  65 .   The valve of the ink outlet  65  of the ink refill container  63  may be provided with a different number of slits  75 , for example, two slits or four slits, as long as the number of slits  75  is more than one. In addition, the valve is not limited to the slit valve provided with the slits  75 , and may be a valve that is not provided with the slits  75  and that displaces in a valve-open direction when pushed from below by the needle  56 .   The positioning portion  73  in the ink refill container  63  is not limited to a flat shape, and may have a shape including one or more protrusions or ribs if the positioning portion  73  is to abut against the upper surface (receiving surface)  58  of the ink refill adapter  47  when the ink is refilled.       

     REFERENCE SIGNS LIST 
       40  . . . ink refill unit,  41  to  45  . . . ink tank,  46  . . . ink refill tube,  47  . . . ink refill adapter,  48  . . . step portion,  49  . . . ink storage chamber,  50  . . . visual recognition portion,  53  . . . ink inlet,  54 ,  55  . . . flow passage,  56  . . . needle (ink inlet flow passage portion),  57  . . . remaining ink sensor,  58  . . . upper surface (receiving surface),  59  . . . lower surface (tank engaging portion),  60  . . . through hole,  61  . . . concave portion (first fitting portion),  62  . . . first concave/convex portion (identification unit),  63  . . . ink refill container,  64  . . . container main body,  65  . . . ink outlet,  66  . . . ink outlet-forming portion,  67  . . . container appendage,  69  . . . male threaded portion,  70  . . . protrusion,  71  . . . convex portion (second fitting portion),  72  . . . second concave/convex portion,  73  . . . positioning portion,  74  . . . valve,  75  . . . slit,  76  . . . ink storage chamber,  91  . . . joining portion,  92  . . . tubular portion,  93  . . . outflow passage,  94  . . . end surface,  102  . . . holder,  103  . . . flange portion,  113  . . . tank-side positioning portion,  119  . . . inlet forming portion,  121  . . . adapter-side positioning portion, IK . . . ink.