Abstract:
Generally speaking, in accordance with the invention, an ink cartridge for an ink-jet recording apparatus can include a container formed by a plurality of walls, an ink supply port extending through at least one of said walls of the container to permit ink to pass out of the container, a porous member disposed within the container for transferring ink to the ink supply port, and a projecting member that projects into the container and is formed with an inlet of the ink supply port. The projecting member can engage against and locally compress a portion of the porous member in the region of the inlet of the ink supply port. The projecting member can be formed so that a first region of the container proximal the front wall of the container is shallower than a second region of the container proximal the back wall of the container.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a replenishable ink cartridge for use in an ink-jet printer with a recording head. 
     A prior art ink jet printer in which an ink-containing unit and an ink jet recording head are mounted on a carriage is disclosed in European Patent Publication No. 581,531. In the disclosed printer, to prevent printing failures caused by fluctuation of ink head pressure or air bubbles due to movement of the ink cartridge caused by the movement of the carriage, the ink container is divided into two regions. A first region of the container adjacent the recording head houses ink impregnated in a porous member, and a second region contains liquid ink without a porous member. This structure enables the ink to be conducted to the recording head via the porous member so that the problems arising from movement of the ink in the cartridge are prevented from occurring to a certain extent. 
     As shown in FIGS. 8 and 9, to cause the ink absorbed in a porous member  451  to flow into the recording head (not shown) smoothly, a projecting member  452  is formed inside a container body  440  so as to draw ink toward an ink supply inlet  458  of an ink supply port  450  by locally pressing porous member  451  to selectively increase the capillary force. 
     To improve full-color print quality, on the other hand, an ink-jet recording apparatus has been designed to reduce the granular look of printed material produced by printers of the prior art by using light ink and dark ink to form dots. Such a recording apparatus requires ink of at least six colors: dark magenta, light magenta, dark cyan, light cyan, yellow and black. One problem caused by using an increased number of inks, however, is that the weight of the carriage is increased, which thereby impairs the movement of the carriage and increases the time it takes the carriage to return to a printing position. 
     To mitigate the aforementioned problems, the weight of the carriage is reduced by decreasing the size of each color&#39;s ink cartridge. Consequently, the width of each color in a container body forming the ink cartridge is narrowed to a small dimension. Referring to FIG. 9, as the width of the ink cartridge is narrowed, however, the rigidity of porous member  451  correspondingly increases and a portion  459  of porous member  451  located between a front wall  456  and projecting member  452  is deformed into a V shape, thereby creating a blank space  454 . A portion  460  located between projecting member  452  and a back wall  461  creases such that portion  460  is not pressed against projecting member  452 , thereby creating a blank space  455 . Finally, as is shown in FIG. 8, at a location above projecting member  452 , porous member  451  spans the gap from projecting member  452  to a side wall  463  and an internal wall  464 , thereby creating a blank spaces  453 . Thus, blank spaces  453 ,  454 ,  455  are produced because porous member  451  does not fully occupy the space defined by container body  440 . Even though spaces  453 ,  454 ,  455  may be filled with ink, because spaces  453 ,  454  and  455  are positioned below ink supply inlet  458 , ink stored in such spaces cannot flow to the recording head via ink supply port  480 . Thus, spaces  453 ,  454 ,  455  waste the ink and also may become bubble reservoirs. 
     One possible solution to this problem is to join porous member  451  to container body  440  during the manufacturing process. However, to do so requires that porous member  451  be cut to precise specifications, which is a complicated undertaking. Moreover, the supply of ink from those portions of porous material that would occupy spaces  453 ,  454 ,  455  in such a construction would be reduced because the portions would not be adequately compressed if joined to the walls of container body  440 . 
     Accordingly, it is desirable to provide an improved ink cartridge that overcomes the drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     Generally speaking, in accordance with the invention, an ink cartridge for an ink-jet recording apparatus can include a container formed by a plurality of walls, an ink supply port extending through at least one of said walls of the container to permit ink to pass out of the container, a porous member disposed within the container for transferring ink to the ink supply port, and a projecting member that projects into the container and is formed with an inlet of the ink supply port. The projecting member engages against and locally compresses a portion of the porous member in the region of the inlet of the ink supply port. The projecting member is formed so that a first region of the container proximal the front wall of the container is shallower than a second region of the container proximal the back wall of the container. 
     Further, in a first cross section, the projecting member can have a V-shaped profile at a region proximal to the front wall of the container, a slope region distal to the front wall of the container, and a plateau region containing the ink supply port therebetween. In a second cross section, the projecting member can have a first sloping region and a second sloping region having a plateau region containing the ink supply port therebetween. 
     Accordingly, it is an object of the invention to provide an improved ink cartridge. 
     Another object of the present invention is to overcome the foregoing problems by providing an ink cartridge with a porous member that occupies blank spaces within the container body, without requiring the porous member to be cut to a specific shape. 
     Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. 
     The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the invention, reference is made to the following description taken in connection with the accompanying drawings in which: 
     FIG. 1 is a rear elevational cross-sectional view of an ink cartridge constructed in accordance with a first embodiment of the present invention; 
     FIG. 2 is a side cross-sectional view of the ink cartridge depicted in FIG. 1; 
     FIG. 3 is a rear elevational cross-sectional view of an ink cartridge constructed in accordance with a second embodiment of the present invention; 
     FIG. 4 is a side cross-sectional view of the ink cartridge depicted in FIG. 3; 
     FIG. 5 is a rear elevational cross-sectional view of an ink cartridge constructed in accordance with a third embodiment of the present invention; 
     FIG. 6 is a side cross-sectional view of the ink cartridge depicted in FIG. 5; 
     FIG. 7 is a side cross-sectional view of the ink cartridge constructed in accordance with a fourth embodiment of the present invention; 
     FIG,  8  is a rear elevational cross-sectional view of an ink cartridge of the prior art; and 
     FIG. 9 is a side cross-sectional view of the prior art ink cartridge of FIG.  8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 and 2, an ink tank cartridge constructed in accordance with a first embodiment of the present invention and generally indicated at  10 , is disclosed. Ink cartridge  10  includes a container body  30  formed by a bottom wall  31 , two side walls  32  that extend upwardly from bottom wall  31 , and a front wall  33  and a back wall  34  that extend upwardly from bottom wall  31  and are positioned between side walls  32 . Walls  31 ,  32 ,  33  and  34  form an opening  40 . Container body  30  also includes an ink supply port  13 ,  14 , which extends through an outwardly projecting portion  90 , bottom wall  31 , and an inwardly projecting portion  60  to supply ink contained within container body  30  to an ink supply needle of a recording head (not shown). 
     Container body  30  is designed to accommodate porous member  20 , which is made of a resilient material suitable for absorbing ink. The volume of porous member  20  is larger than the volume of container body  30 , such that, when porous member  20  is inserted into container body  30 , porous member  20  is accommodated in a compressed condition. Preferably, porous member  20  is constructed with a slightly greater length and width than the length and width of opening  40 , and a slightly greater height than container body  30 . 
     Ink cartridge  10  also includes a lid  50 , having an outer surface  52  and inside surface  51  with ribs  16  formed thereon, for sealing opening  40  of container body  30 . 
     As is shown in FIG. 1, inwardly projecting portion  60  includes a plateau includes a plateau  62 , having a plateau top  68 , two plateau sides  69  extending downwardly from plateau top  68 , and sloped portions  64  that slope downwardly from plateau sides  69  to side walls  32 . As such, the dropoff from plateau top includes a plateau  62  to side walls  32  is more gradual than that disclosed in the prior art (see FIG.  8 ), and porous member  20  is more easily accommodated by sloped portions  64 . 
     Referring to FIG. 2, inwardly projecting portion  60  includes a front portion  66 , which is essentially V-shaped in profile, and slopes downwardly from plateau top  68  to a base point  67 , at which point front portion  66  slopes upwardly to meet front wall  33 , and a back portion  65  with a recess  61 , which slopes downwardly from plateau top  68  to meet bottom wall  31  at a point  63 . Base point  67  is preferably positioned higher than point  63 . As such, the volume of container  30  available to accommodate porous member  20  above front portion  66  is less than the volume of container  30  available to accommodate porous member  20  above back portion  65 . 
     Thus, when porous member  20  is disposed within container body  30 , and lid  50  is secured to container body  30 , lid  50 , ribs  16  and inwardly projecting portion  60  act to compress porous member  20 . Referring to FIG. 2, because a first length A measured between plateau top  68  of inwardly projecting portion  60  and rib  16  is less than a second length B measured between bottom wall  31  and rib  16 , a shallow region C is formed between plateau top  68  of inwardly projecting portion  60  and rib  16 , and a deeper region D is formed between projecting member  60  and back wall  34 . Because porous member  20  has a constant height, that portion of porous member  20  contained within shallow region C is compressed more than the portion of porous member  20  contained within deeper region D. As such, recess  61  of back portion  65  accommodates porous member  20  without forming any gap with respect to container  30 , and that portion of porous member  20  adjacent front portion  66  of projecting member  60  is deformed and accommodated by front portion  66  such that gaps are not formed between front wall  33  and back portion  65 . In this manner, porous member  20  occupies container body  30  such that no blank spaces are produced between projecting member  60  and porous member  20  or between front wall  33  and side walls  32  and porous member  20 . 
     Inwardly projecting portion  60  includes an ink supply port portion  14 , which terminates in an ink inlet  22  extending in the longitudinal direction and formed in plateau top  68 , outwardly projecting portion  90  includes an ink supply portion  13  for supplying ink contained in container body  30  to an ink supply needle (not shown), ink inlet  22  and ink supply port portion  13 . A packing member  15  is inserted into ink supply port portion  14  such that packing member  15  forms a fluid-tight fit with the ink supply needle (not shown) when the ink supply needle is inserted into ink supply port portion  13 . A filter  12 , preferably made of a mesh material, is fuse-bonded to cover ink inlet  22 . 
     Ink supply portion  13  is sealed with a film  55  so as to accommodate porous member  20  in container body  30  in a negative pressure environment. Preferably, ink supply port portion  13  is sealed after porous member  20  and ink are inserted into container body  30 . To supply ink to container body  30 , a supply needle (not shown) is inserted into an ink injection port  17  formed in lid  50  proximate front portion  66 , and then an exhaust needle (not shown) is inserted into a space formed adjacent ribs  16  through an exhaust through-hole  18  formed in lid  50 , so that porous member  20  absorbs a predetermined quantity of ink as the air is exhausted. A sealing film  56  is fused to outer surface  52  of lid  50  at the state when ink has been injected into container body  30 . 
     Referring to FIGS. 3 and 4, an ink tank cartridge  110  constructed in accordance with a second embodiment of the invention is depicted. Ink tank cartridge  110  of this embodiment differs from the first embodiment in that the weight of ink cartridge  110  may be reduced by forming hollow portions  119  in bottom wall  131  and inwardly projecting portion  160 , the inner side walls of said hollow portions  119  being essentially aligned with the side walls of outwardly projecting portion  190 , thereby facilitating high-speed printing. 
     Reference is now made to FIGS. 5 and 6, which disclose an ink tank cartridge constructed in accordance with a third embodiment of the invention, wherein similar reference numerals indicate similar structure. An ink cartridge  210  includes a container body  230  formed by a bottom wall  231 , two side walls  232  that extend upwardly from bottom wall  231 , and a front wall  233  and a back wall  234  that extend upwardly from bottom wall  231  and are positioned between side walls  232 . Walls  231 ,  232 ,  233  and  234  form an opening  240 . Unlike the first embodiment, container body  230  includes at least two partition walls  270 ,  271 , which divide container body  230  into three chambers  281 ,  282 ,  283  for accommodating porous members  220 ,  221 ,  223 . 
     Chambers  281 ,  282 ,  283  respectively include inwardly projecting portions of which  260  and  261 , respectively, are shown, and which are preferably integral with the walls of the respective chambers  281 ,  282 ,  283 . Chambers  281 ,  282 ,  283  also include ink supply partitions and ports, of which  213 ,  214  and  216 ,  217  are respectively shown. Ink supply portions  213 ,  214  and ink supply ports  216 ,  217  extend, respectively, through upwardly projecting portions  260 ,  261  and outwardly projecting portions  290 ,  291 , to supply ink contained within chambers  281 ,  282 ,  283  to ink supply needles (not shown). Ink supply port portions  214 ,  217  respectively terminate in an ink inlet, of which only  225  is shown, extending in the longitudinal direction formed in the respective plateau top, of which  268 ,  269  are shown. 
     Referring to FIG. 5, each inwardly projecting portion  260 ,  261  includes a plateau top  268 ,  269  and two short plateau sides  272 ,  277 , respectively, each extending downwardly from plateau top  268 ,  269  to plane portions  224 ,  225 . Plateau top  268 ,  269  are formed proximal to ink supply portions  214 ,  217  and extend upwardly from plane portion  224  a distance H, such that porous members  220 ,  221 ,  223  are compressed when inserted into chambers  281 ,  282 ,  283 , and blank space is not produced between porous members  220 ,  221 ,  223 , and plane portions  224 ,  225  and plateau top  268 ,  269 . 
     Referring to FIG. 6, projecting member  260  includes a front portion  266 , which has an essentially V-shaped cross-sectional profile having a low point  267  and is proximal front wall  233 , and a back portion  265  with a recess  261 , which slopes downwardly from plateau top  268  to meet bottom wall  231  at a point  263 , and is proximal back wall  234 . Low point  267  and plane portions  224 ,  225  are preferably positioned higher than point  263 . As such, the container volume available to accommodate porous member  220  above front portion  266  and above plateau top  268  is less than the container volume area available to accommodate porous member  220  above back portion  265 . 
     Ink supply port portions  213 ,  214  receives packing member  215 ,  292 . An ink injection port  277  and an exhaust throughhole  218  are formed in lid  250 , each of which is constructed similarly to their counterparts described above in connection with the first embodiment. 
     Thus, when porous member  220  is disposed within chamber  281 , and lid  250  is secured to the container body, lid  250 , ribs  216  formed on an inner surface  251  of lid  250 , and projecting member  260  act to compress porous member  220 . Referring to FIGS. 5 and 6, because a first length E measured between projecting member  260  and rib  216  is less than a second length F measured between bottom wall  231  and rib  216 , a shallow region M is formed between projecting member  260  and front wall  233 , and a deeper region P is formed between projecting member  260  and rib  216 . Because porous member  220  has a constant height, that portion of porous member  220  contained within shallow region M is compressed more than the portion of porous member  220  contained within deeper region P. As such, recess  261  of back portion  265  accommodates porous member  220  without forming any empty space with respect to chamber  281 , and that portion of porous member  220  adjacent front portion  266  of projecting member  260  is deformed and accommodated by front portion  266  such that blank space is not formed between front wall  233  and back portion  265 . In this manner, porous member  220  occupies the container body such that no blank spaces are produced between projecting member  260  and porous member  220  or between front wall  233  and side walls  232  and porous member  220 . 
     Accordingly, when chamber  281  thus constructed is loaded with porous member  220 , a region of the porous member  220  opposite ink supply port  214  is most strongly compressed by projecting member  260  and plateau top  268  formed thereon. As such, porous member  220  is prevented from being deformed at an extreme angle, and no blank space is produced between the container body and porous member  220 . Further, the region dislocated by plateau top  268  is deformed along the bottom of chamber  281  along front portion  266  and back portion  265  such that porous member  220  is accommodated in chamber  281  without forming blank space. 
     In this manner, porous members  220 ,  221 ,  223  occupy chambers  281 ,  282 ,  283  of container body  230 , respectively, such that no blank space is produced between projecting member  260  and porous member  220  or between front wall  233  and side walls  232  and porous member  220 . 
     While the foregoing description has focused on a cartridge with ink contained in chambers having porous members by way of example, the present invention is also applicable with the same effect to an ink cartridge having one chamber for holding ink and a second chamber containing a porous member. Such an embodiment is shown in FIG. 7, wherein ink cartridge  310  includes a container body  330  divided into an ink chamber  391  and a foam chamber  392  by means of a partition wall  370  having a through-hole  395  in the lower portion of wall  370 . Ink is contained in porous member  320  within foam chamber  392 , and ink chamber  391 , and ink is supplied via porous member  320  to a recording head (not shown). 
     Although a description has been given of the case where the ink supply port is vertically positioned and connected to the recording head in the aforesaid embodiments of the present invention it is understood that the effect is also achieved by horizontally positioning the ink supply port and connecting it to the recording head because ink may be introduced into the ink supply port by the capillary force of the porous material. 
     It will thus be seen that the objects set forth above, among those made apparent from the preceding description are efficiently obtained and, since certain changes may be made in carrying out the above method and in the constructions set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.