Patent Publication Number: US-6908184-B2

Title: Ink cartridge for ink-jet printing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This patent application is a continuation of application Ser. No. 09/686,877, filed on Oct. 12, 2000, now U.S. Pat. No. 6,634,738. 

   BACKGROUND OF THE INVENTION 
   This patent application claims priority based on a Japanese patent application, H11-290189 filed on Oct. 12, 1999, the contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an ink cartridge detachably attached to a printing apparatus and supplying ink to a printhead of the printing apparatus which ejects ink droplets in accordance with a printing signal. 
   2. Related Art 
   Typically, a printhead of an ink-jet printing apparatus connects with an ink cartridge via an ink supply channel. The printhead is designed to receive ink from the ink cartridge. The printing apparatus is provided with a hollow ink supply needle in the ink supply channel to supply ink to the printhead. The ink cartridge is formed with an ink supply port for supplying ink to the printhead. When the ink cartridge is mounted on the printing apparatus, the hollow ink supply needle is inserted into the ink supply port of the ink cartridge and ink is supplied to the printhead via the hollow ink supply needle. 
   Unexamined Japanese patent applications (OPI) Nos. Hei. 5-229137 and Hei. 9-174879 disclose an ink cartridge of this structure including a valve member at an upper part of the ink supply port, i.e., inside of the ink cartridge. The ink supply port of the ink cartridge of this type opens when the ink supply needle is inserted, and closes when the ink supply needle is removed. Thus, the ink cartridge is capable of preventing leakage of ink or is capable of being repeatedly attached to the printing apparatus. On the other hand, Unexamined Japanese patent application (OPI) No. Hei. 7-232438 discloses an ink cartridge having a semiconductor memory device that stores data relating to the ink cartridge. 
   The conventional valve member as mentioned above, however, has a drawback as the connection between the semiconductor memory device of the ink cartridge and a control unit of the printing apparatus is inadequate. More specifically, as the valve member is always urged by a spring in an insertion direction of the ink supply needle in order to seal the ink supply port, the ink cartridge does not completely fit to a carriage of the printing apparatus because the resilient force of the spring pushes the cartridge up to some extent with respect to the carriage after the ink cartridge is mounted on the carriage. Such results in that the accurate positioning of the ink cartridge with respect to the carriage is hardly accomplished, and if a memory device is mounted on the ink cartridge, the connection of terminals of the memory device to the contact member of a circuit unit of the printing apparatus may be failed due to the deviation caused by the resilient force of the spring urging the valve member. 
   Further, if the conventional ink cartridge is detached from the carriage of the printing apparatus to exchange to a cartridge of different kind or type while the original ink cartridge is not depleted, the ink may leak out of the ink cartridge through the ink supply port. Such a problem would be more emphasized when the ink cartridge is recycled and the valve or packing becomes worn out and, accordingly, the sealability of the valve mechanism is deteriorated. 
   In addition, if the memory device comes into contact the terminal of the printing apparatus whereas the ink supply needle does not correctly enter the ink supply port and thus still not ready for supplying ink, the printing operation may start and air would be conveyed to the nozzles of the printhead. Such could result in a serious problem in giving damage to the printhead, and no recovery can be expected without exchanging the printhead. Therefore, it has been required an appropriate interrelationship of the contact electrode of the memory device with the engagement between the ink supply port and the ink supply needle. 
   SUMMARY OF THE INVENTION 
   The present invention was made in view of the foregoing drawbacks accompanying the conventional ink cartridge. Therefore, it is an object of the present invention to provide an ink cartridge capable of performing an adequate connection between a memory device mounted on the ink cartridge and an external circuit unit, regardless of a reactive resilient force of a spring for urging a valve, so that the memory device of the ink cartridge is capable of electrically connecting in a stable manner with the external circuit unit. 
   Another object of the present invention is to provide an ink cartridge capable of preventing ink from leaking out through the ink supply port even though the ink cartridge is detached from the printing apparatus for exchanging while ink is not depleted. 
   Still another object of the invention is to provide an ink cartridge capable of achieving an appropriate interrelationship of the contact electrode of the memory device with the engagement between the ink supply port and the ink supply needle. 
   The above and other objects can be attained by a provision of an ink cartridge for an ink jet printing apparatus having a printhead which ejects ink droplets onto a recording medium and an ink supply needle introducing ink to the printhead which, according to the present invention, includes: a substantially rectangular housing for containing ink therein, said housing having a first outer wall and a second outer wall which is substantially perpendicular to said first outer wall; an ink supply port formed in said first wall for directing ink in said housing to the printhead; a valve mechanism arranged in said ink supply port comprising: a valve seat allowing the ink supply needle to pass therethrough; a valve body movable along the axis of said ink supply port; and an elastic member biasing said valve body against said valve seat, and a memory device for storing information relating to ink mounted on said second wall of said housing and substantially in parallel therewith, said memory device being arranged in the vicinity of said ink supply port, and said second wall extending in a direction parallel with a direction along which the ink supply needle is insertable into said valve seat, said memory device comprising a substrate and a plurality of electrode terminals arranged on one surface of said substrate. 
   The memory device may be disposed on a center line of the second wall of the housing. The second wall may have a projection which engages with a hook of an ink cartridge holder of the printing apparatus. The housing may be formed with a concave portion in which the memory device is accommodated. The ink cartridge according to any one of the preceding claims, wherein the housing comprises a plurality of ink chambers for different ink, each chamber comprising an ink supply port, and the memory device is disposed substantially at a center of the total width of the plurality of ink chambers. The memory device comprises a substrate, a plurality of electrode terminals arranged on one surface of the substrate and a storage device disposed on the other surface of the substrate. According to the invention, the memory device may include: a substrate; an electrode terminal arranged on one surface of the substrate at a position where the terminal electrically connects to a contact member of the printing apparatus when the ink supply needle is inserted into the valve seat up to a regular position where the ink supply needle feeds ink; and a storage device secured on the substrate, the storage device communicating with the printing apparatus when the ink cartridge is mounted on the printing apparatus. 
   According to the invention, the length of the terminal along the direction of insertion of the ink supply needle into the valve seat is longer than the maximum length of entry of the ink supply needle into the ink supply port from the valve seat, subtracted by a length that the ink supply needle is pushed back by a resilient force of the elastic member as a reactive force thereof generated by urging the valve body. The terminal starts to connect electrically with the contact member of the printing apparatus when the tip end portion of the ink supply needle comes into contact with the valve body. The terminal along the direction of insertion of the ink supply needle into the valve seat is longer than the length that the ink supply needle slides into the housing while pushing the valve body against the elastic member. The housing comprises a cover plate, the cover plate includes: a through-hole; an elongated groove which is in fluid communication with the inside of the housing through the through-hole; and a film covering the top of both the through-hole and the groove so that air flows through the groove and the through-hole into the housing. 
   The ink cartridge further includes a cylindrical packing member disposed in the ink supply port for communicating an interior of the housing with the printhead through the ink supply needle, wherein the valve body of the valve mechanism is disposed at the housing side of the cylindrical packing member, and always urged by the elastic member to seal the cylindrical packing member. The ink cartridge may further includes a. porous member accommodated in the housing for holding ink. A capillary force of the porous member is greater in the vicinity of the ink supply port than other parts of the porous member. 
   According to another aspect of the invention, the above objects can be achieved by a provision of an ink jet printing apparatus which includes: a printhead for ejecting ink droplets onto a recording medium; and an ink container supplying ink contained therein to the printhead, the ink container comprising: a first wall; a second wall; and an ink supply port formed in the first wall for directing ink in the ink container to the printhead; an ink supply needle for feeding ink from the ink container to the printhead by being inserted into the ink supply port; a valve mechanism arranged in the ink supply port comprising: a valve seat allowing the ink supply needle to pass therethrough; a valve body movable along an axis of the ink supply port; and an elastic member biasing the valve body against the valve seat; and a memory device for storing information relating to ink disposed on the second wall of the container, which second wall extends in a direction parallel with a direction along which the ink supply needle is inserted into the ink supply port, the memory device comprising a substrate and a plurality of electrode terminals arranged on one surface of the substrate. 
   According to still another aspect of the invention, an ink cartridge for an ink jet printing apparatus includes: a cylindrical packing member in an ink supply port thereof for communicating an ink chamber with a printhead through an ink supply needle; and a memory device having electrodes for connection, wherein said electrodes for connection accomplish a conductive relation with external contacts under a condition where the ink supply needle assuredly engages with the cylindrical packing member to allow ink to be supplied. 
   According to still another object of the invention, the above objects can be achieved by a provision of an ink cartridge communicating an ink chamber with a printhead through an ink supply needle and comprising a re-seal structure arranged in an ink supply port thereof, in which the ink cartridge includes a memory device for storing thereon information relating to the ink cartridge and a porous member for holding ink arranged at the ink chamber side of the re-seal member. 
   The ink chamber communicates with ambient air through a capillary action formed in a surface of the cartridge body. The re-seal structure is capable of supplying ink to the printhead in response to a negative pressure applied from the printhead, a porous member for holding ink is disposed, and a packing member is formed at the ink chamber side with a slit which is openable by the insertion of the ink supply needle. 
   According to still another object of the invention, the above objects can be attained by a provision of an ink cartridge for an ink jet printing apparatus which comprises a cylindrical packing in an ink supply port thereof for communicating an ink chamber with a printhead through an ink supply needle, wherein a valve body is disposed at an ink chamber side of the cylindrical packing, and always urged by a spring to seal the cylindrical packing, and a memory means, having electrodes for connection, is disposed on a wall of the ink cartridge, which wall being in parallel with an insertion direction of the ink supply needle. 
   The memory means is disposed on a wall which is in the vicinity of the ink supply port. The memory means has a region on which data of ink consumption amount is stored. The memory means has a region on which a recycling information of the ink cartridge is stored. The memory means may have one surface forming a front surface on which the electrodes for external connection are formed and a rear surface on which a semiconductor storage means is installed. Further, a porous member is housed in the ink chamber at least in the vicinity of the valve body. A porous member is housed in the ink chamber and a filter is provided upstream of the valve body. In addition, a cover plate for sealing an upper part of the ink chamber is formed with an air hole which communicates with ambient air through fine grooves formed in the surface of the cover plate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  shows a perspective view of a black ink cartridge according to the present invention viewed from above, and  FIG. 1B  shows a perspective view of the black ink cartridge according to the present invention viewed from below; 
       FIG. 2A  shows a perspective view of a color ink cartridge according to the present invention viewed from above, and  FIG. 2B  shows a perspective view of the color ink cartridge according to the present invention viewed from below; 
       FIG. 3A  shows a perspective view of the circuit substrate showing the first side, and  FIG. 3B  shows a perspective view of the circuit substrate showing the second side; 
       FIG. 4  shows a cross sectional view of the black ink cartridge when mounted on a carriage of the printing apparatus; 
       FIG. 5  shows an enlarged cross sectional view of the ink supply port; 
       FIG. 6  shows another embodiment of a cartridge according to the present invention; 
       FIG. 7A  shows upper side of the cover member of the black ink cartridge, and  FIG. 7B  shows upper side of the cover member  22  of the color ink cartridge; 
       FIG. 8A  shows the black ink cartridge with a film, and  FIG. 8B  shows the color ink cartridge with a film; and 
       FIG. 9  shows another embodiment of the valve member. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention will now be described in detail with reference to accompanying drawings. This does not intend to limit the scope of the preset invention, but: exemplify the invention. All of the features and the combinations thereof described in the embodiment are not necessarily essential to the invention. 
     FIGS. 1A and 1B  show, merely as an example, a black ink cartridge for an ink-jet printing apparatus. As shown in the figures, an ink cartridge  1  is substantially rectangular parallelepiped. The ink cartridge  1  is provided with a housing  2  formed with an ink chamber  60  (shown in  FIG. 4 ) and an opening, and a cover member  3  sealing the opening of the housing  2 . The ink cartridge  1  further includes an ink supply port  4  formed in one outer wall thereof, i.e., a bottom wall  2   a  in this embodiment. The printing apparatus includes a printhead with nozzles and an ink supply needle which is held in fluid communication with the printhead. The ink supply port  4  of the ink cartridge  1  is designed to supply ink to the printhead through the ink supply needle of the printing apparatus when the ink cartridge  1  is mounted on the printing apparatus and the ink supply needle is inserted in the ink supply port  4 . The bottom wall  2   a  has substantially square shape formed with two edges of longer width and the other two edges of shorter width. The ink supply port  4  is formed at a position closer to one of the shorter edges than the other of the shorter edges. 
   The ink cartridge  1  further includes a memory device  6  having a circuit substrate secured to one wall other than the bottom wall  2   a . The memory device  6  is placed in the vicinity of the ink supply port  4  and preferably, on a side outer wall  2   b  which is in parallel with the insertion direction of the ink supply needle  52 , shown in FIG.  4 . As shown in  FIGS. 1A and 12 , the memory device  6  is disposed on a center line of the side wall  2   b  of the housing  2 , which wall has a shorter width than the other wall of the housing  2 . The housing  2  is substantially rectangular in shape, and the side wall  2   b  of which is substantially perpendicular to the bottom wall  2   a  on which the ink supply port  4  is formed. Further, the memory device, which has a flat substrate, is disposed substantially in parallel with the side wall  2   b.    
   Because the ink supply port  4  of the ink cartridge  1  must be accurately positioned with respect to the ink supply needle of the printing apparatus, more accurate positioning around the ink supply port is accomplished than the other part of the ink cartridge. Accordingly, as the memory device  6  is disposed in the vicinity of the ink supply port  4  according to the present embodiment, an accurate positioning of the memory device  6  with respect to the contact member of the printing apparatus side is necessarily attained. In addition, when the ink cartridge  1  is mounted on the carriage, the level of deviation in position of the ink cartridge  1  with the carriage is less at the center of the ink cartridge than at the side edge parts thereof. Therefore, as the memory device  6  is disposed at the center in the widthwise direction of the side wall  2   b , the level of deviation in position of the memory device  6  is necessarily less. 
   According to the present embodiment, the housing  2  is formed with a concave portion  101  in which the memory device  6  is accommodated. 
   The ink supply port  4  is initially sealed with a sealing member  7  so that air or bubbles do not enter the ink supply port  4  or ink does not leak out of the ink supply port  4  before use. The ink cartridge  1  is formed with a protruding portion  10  which is designed to engage with a hook  102  of a cartridge holder of the printing apparatus for the purpose of aiding mounting and detaching of the ink cartridge  1  on and from the cartridge holder of the printing apparatus. As the protruding portion  10  extends from the side wall  2   b  on which the memory device  6  is mounted, the positioning accuracy of the memory device with the contact member of the printing apparatus can be attained. 
     FIGS. 2A and 2B  show, as an example, a color ink cartridge  20 . Similar to the black ink cartridge  1  shown in  FIGS. 1A and 1B , the ink cartridge  20  is substantially rectangular parallelepiped. The ink cartridge  20  has a housing  21  the interior of which is separated into a plurality of ink chambers by partition walls for accommodating different inks such as different color. According to this embodiment shown in  FIGS. 2A and 2B , five ink chambers  23  to  27  are defined, and each of the ink chambers  23  to  27  has an opening. The ink cartridge further  20  has a cover member  35  sealing all the openings of the ink chambers  23  to  27 . The ink cartridge  20  includes a plurality of ink supply ports  28  to  32  on one of its sides, each corresponding to the ink chambers  23  to  27 . Each of the ink supply ports  28  to  32  is held in communication with the respective ink chambers  23  to  27 , and is capable of providing ink to a corresponding ink supply needle when the ink supply needle is inserted into each of the ink supply ports  28  to  32 . As illustrated in  FIG. 2B , the ink supply ports  28  to  32  are formed at positions closer to one edge of a wall the other. 
   The ink cartridge  20  is further provided with a memory device  34  secured to one wall other than the wall on which the ink supply ports  28  to  32  are formed. According to the present embodiment, as shown in  FIG. 2B , the memory device  34  is disposed substantially at a center of the total width of the plurality of ink chambers  23  to  27 . The memory device  34  is positioned in the vicinity of the ink supply ports  28  to  32  and stores therein, for example, data for specifying the ink cartridge  20 . 
   The ink supply ports  28  to  32  are initially sealed with a sealing member  35  so that air or bubbles do not enter ink supply ports  28  to  32  or ink does not leak out of the ink supply ports  28  to  32  before use. The ink cartridge  20  is formed with a protruding portion  36  which is designed to engage with a hook of the printing apparatus for aiding mounting and detaching of the ink cartridge  20  on the cartridge holder of the printing apparatus. 
     FIGS. 3A and 3B  are perspective views of the memory device  6  or  34 , showing a first side and a second side, respectively. When the memory device  6  or  34  is mounted to the ink cartridge  1  or  20 , respectively, the second side shown in  FIG. 3B  is attached to the ink cartridge  1  or  20 . Thus, the first side shown in  FIG. 3A  is seen on the surface. The first side is formed with electrodes  42  and  43  which are designed to connect to a contact  40 , shown in  FIG. 4 , of the cartridge holder of the printing apparatus. A semiconductor storage device  44  is attached on the second side, i.e., rear side of the memory device  6  or  34 . The semiconductor storage device  44  can be accessed by the cartridge holder of the printing apparatus via the electrode  42  and  43  of the memory device  6  or  34  and the contact  40 , so that information relating to ink or ink cartridge can be stored in or read out from the storage device  44 . The memory device  6  is provided with a substrate  103 , a plurality of electrode terminal;  42 ,  43  and the semiconductor storage device  44 . The electrode terminals  42 ,  43  are arranged on a front surface of the substrate  103  and the storage device  44  is disposed on the other, rear surface of the substrate  103 . Because the semiconductor storage device, i.e., the chip; is disposed on the rear side of the substrate  103 , it is not exposed when the memory device is attached to the ink cartridge  1  and there is no possibility that a user may cause damage even though he drops the ink cartridge  1  on a floor. 
   The semiconductor storage device  44  is formed of an electrically rewritable memory such as a nonvolatile memory such as, for example, EEPROM. When the ink cartridge  1  or  20  is shipped from a manufacturing factory, data related to ink or to the ink cartridge  1  or  20  is previously written on the semiconductor storage device  44 . The previously written data may be, for example, a serial number for specifying the cartridge  1  or  20 , volume of ink contained in the ink cartridge  1  or  20 , and data related to a trademark indicating a manufacturer of ink or the ink cartridge  1  or  20 . The semiconductor storage device  44  is formed to have an area where a volume of ink consumed by a user can be written on. 
     FIG. 4  shows a cross sectional view of the black ink cartridge  1  when mounted on a carriage  51  of the printing apparatus. The printing apparatus includes a printhead  50  and an ink supply needle  52 . When the ink cartridge  1  is mounted on a predetermined position of the carriage  51  on which the printhead  50  is secured, the ink supply needle  52  forms a sealing connection with the ink supply port  4  of the ink cartridge  1  to be held in communication with the ink chamber  60  via the ink supply port  4 . 
   The ink supply needle  52  is hollow and formed from a cylindrical body having a tapered portion at its tip end. Therefore, the ink supply needle  52  is easily inserted into and removed from the ink supply port  4 . When the ink supply needle  52  is inserted in the ink supply port  4 , the ink supply needle  52  forms a sealing connection with a packing member  61  fitted in the ink supply port  4 , which will be described herein below. 
     FIG. 5  shows an enlarged cross sectional view of the ink supply port  4  and a valve mechanism arranged therein. The packing member  61  is press-fitted in the ink supply port  4 . The packing member  61  defines a hole substantially at a center thereof, allowing the ink supply needle  52  to pass therethrough, shown in FIG.  4 . 
   The packing member  61  is made of an elastic material such as a rubber material including a silicon rubber, a chloroprene rubber, a butyl rubber, a ethylene-propylene rubber, a nitrile rubber, and an elastomer material. 
   The hole of the packing member  61  has a tapered portion  62  which tapers out to guide the ink supply needle  52  of the printing apparatus, and a cylindrical fitting portion  63  in the vicinity of the ink chamber  60 . The valve mechanism includes a valve body  65  installed in the ink supply port  4  between the packing member  61  and the ink chamber  60 . The valve member  65  is always urged vertically with respect to the packing member  61  by a spring  64 . Thus, the valve body  65  and the packing member  61  form a sealing connection. The valve body  65  is urged by the ink supply needle  52  against the resilient force of the spring  64  to open the ink supply port  4 , when the ink supply needle  52  is inserted in the ink supply port  4 . 
   The length of the electrode terminals  42  and  43  of the memory device  6  along the direction of insertion of the ink supply needle  52  into the packing member  61  is designed to be longer than the maximum length of entry of the ink supply needle  52  into the ink supply port  4  from the packing member  61 , subtracted by a length that the ink supply needle is pushed back by a resilient force of the spring  64  as a reactive force thereof generated by urging the valve body  65 . The terminal electrodes are arranged on the substrate of the memory device  6  in a position where the electrode terminals start to connect electrically with the contact member  40  of the printing apparatus when the tip end portion of the ink supply needle  52  comes into contact with the valve body  65 . In addition, the length of the electrode terminals along the direction of insertion of the ink supply needle  52  into the packing member is longer than the length that the ink supply needle  52  slides into the housing while pushing the valve body  65  against the resilient force of the spring  64 . 
   Referring back to  FIG. 4 , when the ink cartridge  1  is mounted on the cartridge holder  70  and a lever  71  is pushed down, the tip of the ink supply needle  52  penetrates the sealing member  7  sealing the ink supply port  4 . Then, the tip of the ink supply needle  52  urges the valve body  65  to open against the resilient force of the spring  64  so that the ink chamber  60  becomes held in communication with the printhead  50 . The memory device  6  connects to a control unit installed in the printing apparatus, not shown in the drawings, via the contact  40  formed at the cartridge holder  70  in this embodiment. The contact  40  has resiliency in the vertical direction with respect to the insertion direction of the ink supply needle  52 . 
   The memory device  6  according to the present embodiment is mounted on a side wall which is substantially in parallel with the insertion direction of the ink supply needle  52 . Therefore, by forming the electrodes  42  and  43  of the memory device  6  slightly larger than the size necessary to contact with the contact  40 , the electrode terminals  42  and  43  of the memory device  6  can ensure the connection with the contact  40  of the carriage  51 , regardless of the distance between the ink cartridge  1  and the cartridge holder  70  of the printing apparatus. Furthermore, by forming the electrode terminal  42  relatively longer along the insertion direction of the ink supply needle  52 , the electrode terminals  42  and  43  of the memory device  6  can ensure the connection between the contact  40  of the cartridge  1  regardless of the insertion direction of the ink supply needle  52 . It is desirable that the memory device  6  and the contact  40  are placed such that the contact  40  forms an electric contact with the electrodes  42  and  43  of the memory device  6  only when the ink supply needle  52  is inserted in the ink supply port  4  to open the valve member  65  and ink is supplied from the ink chamber  60  to the printhead  50 . 
   With the afore-described structure, the fact that data from the storage device  44  can be read out means that the ink cartridge  1  is appropriately mounted on the cartridge holder  70 , because the storage device  44  can only be read out when the electric connection between the electrodes  42  and  43  and the contact  40  is formed. Therefore, even if a program for controlling the printing operation of the printing apparatus includes a sequence judging that the ink cartridge  1  is mounted on the cartridge holder  70  by the fact that the data can be read out from the storage device  44 , there is no danger that the printing apparatus starts printing operation when ink is not provided to printhead  50 . Thus, damage to the printhead  50  can be prevented. 
   With this structure, the printhead  50  can be prevented from sucking air when the ink cartridge  1  is not appropriately mounted on the cartridge holder  70 . This fact prevents waste of a large amount of ink for recovering the operation of the printhead  50  that is required when the printhead  50  sucks air or bubbles. 
   Furthermore, the ink supply port  4  is formed at a position closer to one of the shorter edges than the other of the bottom wall  2   a  of the ink cartridge  1  and is retained at a constant position by the ink supply needle  52  provided on the carriage  51  when the ink supply needle  52  is inserted in the ink supply port  4 . Thus, the memory device  6  disposed in the vicinity of the ink supply port  4 , which is formed on one wall of the ink cartridge  1 , is also retained at a relatively constant position. Therefore, the electric connection between the electrodes  42  and  43  of the memory device  6  and the contact  40  is ensured without changing the position of the memory device  6  even when the carriage  51  traverses and generates shaking. 
   When the printing operation is started and ink is consumed by the printhead  50 , that is, when printhead  50  ejects ink droplets, under this condition, the control unit such as a micro computer, not shown in the drawings, counts ejected ink droplets to calculate the amount of consumed ink. The control unit writes the amount of consumed ink on the semiconductor storage device  44  of the memory device  6  via the contact  40 . 
   It is preferable for the printing apparatus to apply a variety of ink cartridges in accordance with different types of printing mediums in order to enable a high print quality or a desired printing condition. 
   As shown in  FIG. 5 , which shows a condition where the ink cartridge  1  or  20  is not in use, the valve body  65  of the ink cartridge  1  or  20  is urged by the spring  64  to close the ink supply port  4 . Therefore, even when the ink cartridge  1  or  20  is detached from the carriage  5  for exchange, ink does not leak and undesirable air and bubbles do not enter the ink chamber  60  or  23  to  27 . 
   The length of the terminal along the direction of insertion of the ink supply needle into the packing member and into said valve seat is longer than the maximum length of entry of the ink supply needle into said ink supply port from said valve seat, subtracted by a length that the ink supply needle is pushed back by a resilient force of said elastic member as a reactive force thereof generated by urging said valve body. 
   As the semiconductor storage device  44  stores information relating to the amount of the consumed ink, the amount of the ink remaining in the ink chamber  60  or  23  to  27  can be calculated, even when the ink cartridge  1  or  20  is detached once and remounted on the ink carriage  51 . Thus, an ink end or near end condition of the ink cartridge  1  can readily be detected. 
     FIG. 6  shows another embodiment of an ink cartridge according to the present invention. The cartridge  101  includes a porous member  80  and a filter  171  in the ink chamber  60 , or  23  to  27 . The filter  171  is positioned between the ink chamber and the ink supply port  4  and has a flat shape one side of which is in contact with the porous member  80 . The porous member  80  has a capillary force which is smaller than a negative pressure generated by the nozzles of the printhead  50  but large enough to retain ink therein. The filter  171  also has a capillary force which is larger than the capillary force of the porous member  80  and smaller than the negative pressure generated by the printhead  50 . The filter  171  may be a plate-like member formed of a porous material or a mesh material. The pore size or mesh size of the porous member  80  and the filter  171  defines the capillary force thereof. In other words, the capillary force of the porous member  80  and the filter  171  can be controlled by selecting an appropriate pore size or mesh size. 
   A cover member  3  of the ink cartridge  101  is formed with a rib portion including a plurality of protruding portions  72 , each of which are spaced apart from each other by a predetermined distance. Owing to these protruding portions &#39; 72 , a space is defined in the ink chamber  60  between the porous member  80  and the cover member  3  or  22 . A part of the ink supply port  4  is formed to protrude inside the ink chamber  60 , or  23  to  27 . 
   Therefore, the porous member  80  is highly compressed in the vicinity of the ink supply port  4  to reduce the pore size so that the capillary force of the porous member  80  becomes greater in the vicinity of the ink supply port  4  than other parts of the porous member  80 . 
   The cover member  3  or  22  has an ink injecting hole  73  or  74  and an air hole  75  or  76  which is designed to be open to the external ambient air. 
     FIG. 7A  is a perspective view showing an upper side of the cover member  3  of the black ink cartridge. The cover member  3  has a fine, winding groove  77  connecting the air hole  75  and an air releasing hole  79 . The air releasing hole  79  is previously sealed by a film before use of the ink cartridge, which will be described in the following, but becomes open to the external ambient air when the film is removed for use. 
     FIG. 7B  is a perspective view showing an upper side of the cover member  22  of the color ink cartridge. The cover member  22  has fine grooves  78  connecting the air hole  76  to air releasing holes  180 . The air releasing holes  180  are previously sealed by a film before use of the ink cartridge, which will be described in the following, but become open to the external air when the film is removed for use. 
   Ink is introduced into the ink chamber of the ink cartridge as will be described in the following. First, the ink supply port  4  is sealed by a film. Then, a hollow ink introducing tube, not shown in the drawings, is inserted in the ink injecting hole  73  or  74 , and a vacuum tube is inserted in the air hole  75  or  76 . At this time, the ink chamber  60  or  23  to  27  is under a low pressure or a vacuum pressure and the ink is introduced from the ink introducing tube under this condition. 
   As the ink chamber  60  or  23  to  27  is maintained under the low-pressure condition, i.e., air is removed from the ink supply port  4  or the porous member  80 , ink can be introduced entirely into the ink chamber  60  or  23  to  27  with little residual air. Thus, whole of the porous member  80  becomes filled with ink. 
     FIGS. 8A and 8B  show the ink cartridges  1  and  2  with films, respectively. 
   After introducing the ink into the ink chamber  60  or  23  to  27 , the ink cartridge  1  or  20  is placed in a vacuum chamber to further decompress the ink chamber  60  or  23  to  27 , if necessary. Then, a film  81  or  82  is attached on the surface of the cover member  3  or  22  to protect the ink chamber  60  or  23  to  27  from ambient air. The film  81  or  82  has a tongue part  81   a  or  82   a  for easily removing a part of the film  81  or  82  when it is used. The ink cartridge  1  or  22  is shipped as a product. The ink cartridge may be packaged in a sealed film bag having a high air-impermeability with a decompressed condition, if necessary. 
   Before using the ink cartridge  1  or  21  thus constructed, a part of the film  81  or  82  is removed by pulling the tongue part  81   a  or  82   a  to open the air releasing hole  79  or  180 . Therefore, the ink chamber  60  or  23  to  27  becomes open to the ambient air via a capillary having high fluid resistance formed by the small groove  77  or  78  and the film  81  and  82 , respectively. 
   After the ink cartridge  1  or  22  is mounted on the cartridge holder and the fluid communication with the printhead  50  is accomplished, when printing is started, the negative pressure from the printhead  50  pulls the ink retained by the porous member  80 . The filter  171  of the ink cartridge  1  or  20  removes air or dust and passes merely ink to the printhead  50 . 
   As shown in  FIG. 5 , since the valve member  65  of the ink cartridge  1  or  20  is always urged by the resilient force of the spring  64 , the ink supply port  4  is closed by the valve mechanism at a time when the ink supply needle  52  comes out of contact with the packing member  61 . Therefore, even when the ink cartridge  1  or  20  is detached from the carriage  5  for changing to a different type of ink for printing, ink does not leak from the ink chamber  60 , and undesirable air and bubbles do not enter the ink supply port  4 . 
   Furthermore, in the preferred embodiment, the ink does not leak from the ink supply port  4  even when the sealing connection between the valve member  65  and the packing member  61  becomes loose, because the ink is retained by the porous member  80  in the ink chamber  60  or  23  to  27  and blocked by the filter  171  having a high capillary force. The ink is retained in the ink chamber  60  or  23  to  27  by the fluid resistance of the capillary action performed by the fine groove  77  or  78  and the film  81  and  82 , respectively. 
   In one arrangement of the embodiment, the packing member  61  may have a slit aperture therein at the ink chamber  60  or  23  to  27  side thereof, which slit can be opened by the insertion of the ink supply needle  52  and can retain the ink by generating a capillary force when the ink supply needle  52  is removed. In such arrangement, the valve member  65  may not be necessary. Thus, the structure of the ink cartridge can be further simplified. 
   As the ink chamber  60  or  23  to  27  is held in communication with the ambient air via the capillary generated by the fine groove  77  or  78  and the film  81  and  82 , respectively, evaporation of the ink can also be prevented. Thus, the memory device can accurately store information relating to the amount of the ink remaining in the ink chamber  60  or  23  to  27 . 
     FIG. 9  is a cross-sectional view showing still another example of an embodiment according to the present invention. In the present embodiment, the ink chamber  60  of an ink cartridge  201  may be separated into an ink chamber  60   a  and a foam chamber  60   b  by a partition wall  83  whose bottom portion is formed with a communication hole  83   a  for communicating the ink chamber  60   a  with the foam chamber  60   b.    
   The ink cartridge  201  accommodates a porous member  84  in the foam chamber  60   b . The filter  71 , the ink injecting hole  73 , and the air hole  75  are provided in the foam chamber  60   b . The ink chamber  60   a  serves as ink storage. The ink cartridge thus constructed can perform the same operation as that of the ink cartridge in the embodiments described above. 
   Furthermore, although the porous member  80  or  84  prevents ink from leaking because of its capillary force in the foregoing embodiments, another ink cartridge which includes only the filter  71  or  171 , without employing any porous member, can also prevent leakage, to a certain extent, of the ink caused by the weakness of the sealing connection between the valve member  65  and the packing member. 
   The ink can be introduced into the ink cartridge  1  or  20  thus constructed by using a refilling unit having the same function as the ink supply needle  52 . The needle portion of the refilling unit is inserted in the ink supply port  4  to open the valve member  65 . Thus, the ink cartridge is recycled. The semiconductor storage device  44  of the memory device  6  may have an area where the number of times of refill of the ink cartridge  1  or  20  can be written in order to regulate the number of recycling or, in other words, to prevent the cartridge from being recycled too many times. Therefore, the recycled cartridge with a high reliability can be produced. 
   As described above, an ink cartridge for an ink jet printing apparatus according to the present invention having a printhead which ejects ink droplets onto a recording medium and an ink supply needle introducing ink to the printhead, the ink cartridge includes: a substantially rectangular housing containing ink therein, said housing having a first outer wall and a second outer wall which is substantially perpendicular to said first outer wall; an ink supply port formed in said first wall for directing ink in said housing to the printhead; a valve mechanism arranged in said ink supply port comprising: a valve seat allowing the ink supply needle to pass therethrough; a valve body movable along the axis of said ink supply port; and an elastic member biasing said valve body against said valve seat, and a memory device for storing information relating to ink mounted on said second wall of said housing and substantially in parallel therewith, said memory device being formed in the vicinity of said ink supply port and said second wall extending in a direction parallel with a direction along which the ink supply needle is inserted into said valve seat. 
   Ink is supplied from the ink chamber of the ink cartridge to the printhead of the printing apparatus when the ink supply needle is inserted in the ink supply port of the ink cartridge. As the memory device is attached on the wall of the ink cartridge which is in parallel with respect to the insertion direction of the ink supply needle, the electric connection between the memory device of the ink cartridge and an external electrode of the printing apparatus can be surely maintained regardless of the variation of the distance between the ink cartridge and the printing apparatus caused by the resilient force of the spring biasing the valve body toward the packing member.