Abstract:
Multi-compartmentalized ink cartridges for ink jet printers and improved methods for making the ink cartridges. The multi-compartmentalized ink cartridge includes a molded, open-topped body having an interior cavity and a printhead surface area opposite the interior cavity. A divider wall is integrally molded with the molded body structure and disposed in the interior cavity to provide at least three segregated ink chambers. The divider wall includes a first wall section and a second wall section attached substantially perpendicular to the first wall section. At least first, second, third molded ink flow paths connect each of the at least three segregated ink chambers with the printhead surface area. The second and third ink flow paths are oriented relative to their corresponding ink chambers for molding with a mold insert tool so that the cartridge body does not require a separately attached member to close mold insert tool insertion areas in the body.

Description:
FIELD OF THE INVENTION 
   The invention relates to ink jet printers and in particular to ink reservoir configurations for multi-color ink cartridges. 
   BACKGROUND OF THE INVENTION 
   Multi-compartmented ink cartridge bodies generally have reduced spacing requirements as compared to multiple single color ink cartridges. There are generally two types of multi-compartmentalized ink cartridges; parallel chamber ink cartridges, and ink cartridges having a T-shaped divider between the chambers. Each of the chambers is filled with a negative pressure inducing device such as a capillary foam, bladders, or lungs. 
   Regardless of the negative pressure inducing device, ink flow paths must be provided from the reservoir area of each chamber to the printhead. The ink flow paths to the printheads from ink cartridges having parallel chambers are quite different from the flow paths in multi-compartmentalized ink cartridges having a T-shaped divider between the chambers. Thus manufacturing techniques for each type of ink cartridge are also quite different. 
   As the cost of materials increases, there is a need for improved ink cartridge designs that enable use of less material and improved production techniques. There is also a need for manufacturing techniques, that enable production of ink cartridges having integral ink flow paths, and ink cartridges that can be formed with fewer process steps. 
   SUMMARY OF THE INVENTION 
   With regard to the foregoing, the invention provides multi-compartmentalized ink cartridges and improved methods for making the ink cartridges. A first embodiment of the invention provides a multi-compartmentalized ink cartridge body for an ink jet printer including a molded unitary body structure having exterior side walls and a bottom wall forming an open-topped, interior cavity, and a printhead surface area on a portion of the bottom wall opposite the interior cavity. A divider wall is integrally molded with the molded body structure and disposed in the interior cavity between the side walls to provide at least three segregated ink chambers within the interior cavity of the body. Each of the ink chambers has a chamber axis, wherein the divider wall includes a first wall section and a second wall section attached substantially perpendicular to the first wall section and each wall section is substantially parallel with at least one chamber axis. At least first, second, and third molded ink flow paths connect each of the at least three segregated ink chambers with the printhead surface area. The ink flow paths each have an ink flow axis with respect thereto. At least the second and third ink flow paths are oriented relative to their corresponding ink chambers for molding with a mold insert tool so that the cartridge body does not require a separately attached member to close mold insert tool insertion areas on one or more of the exterior side walls of the body. 
   In second embodiment, the invention provides a method for making a multi-compartmentalized ink cartridge body for an ink jet printer. The method includes the steps of providing a mold body for molding a unitary body structure. The unitary structure has exterior side walls and a bottom wall forming an open-topped, interior cavity. A printhead surface area is provided on a portion of the bottom wall opposite the interior cavity. A divider wall is disposed in the interior cavity between the side walls, the divider wall having first and second wall sections providing at least three segregated ink chambers within the interior cavity of the body. Each ink chambers has a chamber axis, and at least one ink flow path connecting each of the segregated chambers with the printhead surface. A mold core is provided having first, second, and third chamber forming segments parallel with the chamber axes and a first ink flow path segment pending from the first chamber forming segment. The mold core is inserted into the mold body. The mold body is then injected with a thermoplastic material at a temperature sufficient to form the unitary body structure between the mold core and the mold body. The thermoplastic material is cooled to a temperature sufficient to form a solidified unitary body structure. Then the mold core is removed from the solidified unitary body structure to provide a multi-compartmentalized ink cartridge body, wherein openings on the exterior side walls of the cartridge body for forming the ink flow paths are avoided. 
   In another embodiment, the invention provides a molded unitary body structure having exterior side walls and a bottom wall forming an open-topped, interior cavity, and a printhead surface area on a portion of the bottom wall opposite the interior cavity. A divider wall is integrally molded with the molded body structure and disposed in the interior cavity between the side walls to provide at least three segregated ink chambers within the interior cavity of the body. The divider wall includes a first wall section and a second wall section attached substantially perpendicular to the first wall section, wherein each wall section is parallel with at least one chamber axis. At least first, second, third molded ink flow paths connect each of the at least three segregated ink chambers with the printhead surface area. At least the second and third ink flow paths are oriented relative to their corresponding ink chambers for molding with a mold insert tool through access ports in exterior side wall of the body structure. Injection molded plugs close the access ports in the exterior side wall of the body structure. 
   An important advantage of the invention is that the ink flow paths can be molded integral with a unitary cartridge body without having to attach a separate cover to access openings in an exterior wall of the ink cartridge body for use in forming the ink flow paths. The invention thus eliminates a step of fabricating and gluing a cover plate to the access openings thereby reducing manufacturing costs and increasing product yield. Multi-compartmentalized ink cartridges having separate access covers are often attached with adhesives, which may introduce contaminants into the ink. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings, wherein like reference characters designate like or similar elements throughout the several drawings as follows: 
       FIG. 1  is a top perspective view of an inside cavity of an ink cartridge according to a first embodiment of the invention; 
       FIG. 2  is a side cross-sectional view of an ink cartridge according to the first embodiment of the invention; 
       FIG. 3  is a top plan view of an ink cartridge according to the first embodiment of the invention; 
       FIG. 4  is a top perspective view of an inside cavity of an ink cartridge according to a second embodiment of the invention; 
       FIG. 5  is a side cross-sectional view of an ink cartridge according to the second embodiment of the invention; 
       FIG. 6  is a top plan view of an ink cartridge according to the second embodiment of the invention; 
       FIG. 7  is a top perspective view of an inside cavity of an ink cartridge according to a third embodiment of the invention; 
       FIG. 8  is a side cross-sectional view of an ink cartridge according to the third embodiment of the invention; 
       FIG. 9  is a top plan view of an ink cartridge according to the third embodiment of the invention; 
       FIG. 10  is a perspective view of an ink cartridge according to a fourth embodiment of the invention; 
       FIG. 11  is a side cross-sectional view of an ink cartridge according to the fourth embodiment of the invention; 
       FIGS. 12 and 13  are bottom perspective views of a printhead surface side of ink cartridges according to a fifth embodiment of the invention; 
       FIG. 14  is a top perspective view of an ink jet cartridge according to the first embodiment of the invention and mold tool insert for forming ink flow paths in an ink jet cartridge; 
       FIG. 15  is a side cross-sectional view of an ink cartridge body mold and mold insert for molding an ink cartridge according to the first embodiment of the invention; 
       FIG. 16  is a side cross-sectional view of an ink cartridge body mold and mold insert for molding an ink cartridge according to the second embodiment of the invention; 
       FIG. 17  is a side cross-sectional view of an ink cartridge body mold and mold insert for molding an ink cartridge according to the third embodiment of the invention; 
       FIG. 18  is a side cross-sectional view of an ink cartridge body mold and mold insert for molding an ink cartridge according to the fourth embodiment of the invention; 
       FIG. 19  is a top plan view of an ink cartridge according to a sixth embodiment of the invention; 
       FIG. 20  is a side cross-sectional view of an ink cartridge body according to the sixth embodiment of the invention; and 
       FIGS. 21 and 22  are side cross-sectional views of an ink cartridge body and mold insert tool according to the sixth embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to  FIGS. 1 ,  2  and  3  there is shown a multi-compartmentalized ink cartridge  10  for an ink jet printer in accordance with a first preferred embodiment of the invention. Each ink cartridge  10  includes a unitary body  12  having side walls  14  and  16 , end walls  18  and  20 , and a bottom wall  22 . The bottom wall  22  preferably includes a reservoir section  24  and a printhead section  26  having a printhead area  28 . The side walls  14  and  16 , end walls  18  and  20 , and bottom wall  22  form an open-topped interior cavity  30 . A T-shaped divider wall  32  having a longitudinal section  34  and a transverse section  36  is integrally molded with the body  12  to provide segregated ink chambers  38 ,  40 , and  42 . The longitudinal section  34  and transverse section  36  are disposed in the interior cavity  30  so that each of the ink chambers  38 ,  40 , and  42  has substantially the same void volume. In the alternative, one of the ink chambers  38 ,  40 , or  42  may be provided with a larger volume for containing an ink, which is used in a greater amount than the other ink. Multiple longitudinal sections  34  may also be provided to provide additional ink chambers substantially parallel to ink chambers  40  and  42 . One advantage of the invention is that multiple ink chambers may be provided without increasing the complexity of manufacture of the ink cartridges  10 . It is preferred, however, to provide an ink cartridge  10  having three ink chambers. 
   The cartridge body  12  is preferably molded as a unitary piece in a thermoplastic molding process. The body  12  is preferably made of a polymeric material selected from the group consisting of glass-filled polybutylene terephthalate available from G. E. Plastics of Huntersville, N.C. under the trade name VALOX 855, amorphous thermoplastic polyetherimide available from G. E. Plastics under the trade name ULTEM 1010, glass-filled thermoplastic polyethylene terephthalate resin available from E. I. du Pont de Nemours and Company of Wilmington, Del. under the trade name RYNITE, syndiotactic polystyrene containing glass fiber available from Dow Chemical Company of Midland, Mich. under the trade name QUESTRA, polyphenylene ether/polystyrene alloy resin available from G. E. Plastics under the trade names NORYL SE1 and NORYL 300X and polyamide/poly-phenylene ether alloy resin available from G. E. Plastics under the trade name NORYL GTX. A preferred material for making the body  12  is VALOX 855 resin. 
   First, second, third ink flow paths  44 ,  46  and  48  connect each of the ink chambers  38 ,  40  and  42  with a printhead chip attached to the printhead area  28  of the body  12 . As shown in  FIG. 2 , the ink flow paths  46  and  48  are oriented along an axis as represented by arrow  50 , so that a mold insert can be removed from the body  12  through ink chambers  40  and  42  to form ink flow paths  46  and  48  once the thermoplastic material forming the body  12  has solidified. Likewise, ink flow path  44  can be formed by removing a mold insert through ink chamber  38 , or in the alternative, a mold insert may be removed through the printhead area  28  of the body  12  to form the flow path  44 . Because the mold insert is removable through ink chambers  40  and  42  along the axis represented by arrow  50 , there is no need to remove a mold insert is through an exterior wall of the body  12 , such as side walls  14  and  16 , or printhead wall  52  in the printhead section  26  of the body  12 . Mold and inserts useful for making ink cartridge  10  are described below with reference to  FIGS. 14 and 15 . 
   As shown in plan view in  FIG. 3 , ink flow path  46  provides ink flow from reservoir  40  through filter tower  54  to printhead area  28 . Likewise, ink flow path  48  provides ink flow from ink reservoir  42  through filter tower  56  to printhead area  28 , and ink flow path  44  provides ink flow from ink reservoir  38  through filter tower  58  to printhead area  28 . 
   A second embodiment of an ink cartridge  60  of the invention is illustrated in  FIGS. 4 ,  5 , and  6 . In the second embodiment, removal of a mold insert tool through an exterior wall of the cartridge body  62  is avoided by removing the tool through the printhead area  28  of the body  62  along an axis represented by arrow  64  as shown in FIG.  5 . As in the previous embodiment, filter towers  70  and  72  provide ink through ink flow paths  66  and  68  respectively to the printhead area  28 . In all other respects, the unitary body  62  of this embodiment is substantially similar to the unitary body  12  of the first embodiment. The insert tool for flow path  44  may removed through the ink chamber  38  or through the printhead area  28  of the body  62 . Mold and inserts useful for making ink cartridge  60  are described below with reference to FIG.  16 . 
   A third embodiment of the invention is illustrated in  FIGS. 7 ,  8 , and  9 . In this embodiment, an ink cartridge  80  has a cartridge body  82  with angled end wall  84  and angled transverse section  86 . The wall  84  and section  86  are preferably parallel with arrow  92  which is substantially parallel with flow axes represented by arrow  94  through the ink flow paths  96  and  98  to the printhead area  28 . It will be appreciated that a single mold insert shaped to form chambers  88  and  90  substantially simultaneously with ink flow paths  96  and  98  may be provided with removal of the mold insert along the axes represented by arrow  94 . Likewise ink chamber  100  and ink flow path  102  may be formed with a single insert tool shaped to provide the chamber  100  and flow path  102  with removal of the tool along an axis represented by arrow  104 . Such a mold and insert for forming the chambers  88 ,  90 , and  100  and ink flow paths  96 ,  98 , and  102  are shown in  FIG. 17  described below. 
   In the alternative, transverse wall section  86  may be parallel to end side wall  18  rather than being angled, provided the angle of the flow paths  96  and  98  along axes represented by arrow  94  correspond to the angle of end wall  84 . The angle Θ that end side wall  84  and transverse wall section  86  make with the bottom wall  22  preferably ranges from about 65 to about 75 degrees. 
     FIGS. 10 and 11  illustrate a fourth embodiment of the invention. In this embodiment, an ink cartridge  110  has a unitary body  112  having angled ink chambers  114  and  116  with respect to ink chamber  118 . Ink chambers  114  and  116  have chamber axes  120  and ink chamber  118  has a chamber axis  122 . The angle Φ between axes  120  and axis  122  preferably ranges from about 55 to about 65 degrees. The ink flow paths, such as ink flow path  124  for ink chamber  116 , have ink flow axes  126  which are substantially parallel to chamber axes  120 . Likewise, ink flow path  128  has an axis  130  substantially parallel with chamber axis  122 . 
   As in the cartridge  80  of the third embodiment described above, a single mold insert shaped to form chambers  114  and  116  substantially simultaneously with ink flow paths, such as path  124 , may be provided with removal of the mold insert along the chamber axes  120 . Likewise ink chamber  118  and ink flow path  128  may be formed with a single insert tool shaped to provide the chamber  118  and flow path  128  with removal of the tool along axis  122 . Such a mold and insert are described below with reference to FIG.  18 . 
   In all of the foregoing embodiments illustrated in  FIGS. 1-11 , no exterior wall opening is required for a mold insert to form the ink flow paths for the cartridges. Hence, no separate cover is required to close such wall openings.  FIGS. 12 and 13  provide, as a fifth embodiment of the invention, an ink cartridge  140  that also does not require a separate cover to close access openings in an exterior wall of an ink cartridge body  142 . The ink cartridge  140  is similar to the ink cartridges  10  and  60  shown in  FIGS. 1-6  with respect to the dividing wall sections  32  and  36  and the filter towers for the ink flow paths. However, in this embodiment, access ports  144  are provided in an exterior wall  146  of the printhead section  26  of the ink cartridge body  142 . The access ports  144  enable an mold insert for forming ink flow paths  148  and  150  from the corresponding ink chambers through filter towers  152  and  154 , as described above, for flow of ink to the printhead area  28 . In all of the embodiments described above, the printhead area  28  includes ink channels, such as ink channels  156 ,  158  and  160  in the cartridge body  142 , for flow of ink from the ink chambers to a printhead attached in the printhead area  28  of the cartridges. Flow paths  148  and  150  provide ink flow from their corresponding ink chambers to ink channels  156  and  160 , respectively. 
   As beforementioned, a thermoplastic material is injected into a mold to form the body  142 . After the body  142  has solidified, but before the body  142  is removed from the mold, the mold inserts are removed from ink flow paths  148  and  150  and pins are inserted in filter towers  152  and  154  from the ink chamber side of the cartridge body  142  to block the flow of injection molded plastic material in ink flow paths  148  and  150 . Next an injection tool is partially inserted in access ports  144  to inject molten plastic material therein to form integrally molded plugs  162  closing the access ports  144 . The process described above is referred to as a “two shot” molding process, because two shots of molten plastic material are inserted in the mold for body  142 . The first shot of thermoplastic material provides body  142  and the second shot of thermoplastic material provides plugs  162 . 
   With reference now to  FIGS. 14-18 , illustrative molds and mold inserts for forming the ink cartridges  10 ,  60 ,  80 , and  110  according to the invention will now be described. With reference to  FIGS. 1-3  and  FIG. 14 , as set forth above, mold inserts  180  and  182  are provided to form the ink flow paths  46  and  48  through filter towers  54  and  56  for ink cartridges  10 . In the case of substantially cylindrical ink flow paths  46  and  48 , the inserts  180  and  182  are preferably cylindrical. However, the invention is not limited to cylindrical inserts  180  and  182  and cylindrical ink flow paths  46  and  48 . A wide variety of ink flow path shapes and filter tower shapes such as oval, rectangular, and the like may be formed for all of the embodiments of the invention. 
   The mold  184  for molding ink cartridges  10  is shown in cross-sectional view in FIG.  15 . The mold  184  includes a bottom section  186  and a top section or mold core  188  having an upper section  190  and pending chamber forming segments such as segments  192  and  194  attached to the upper section of the mold core  188 . Segment  192  forms ink chamber  42  and segment  194  forms ink chamber  38  and ink flow path  44 . As described above, mold inserts such as insert  182  is used to form ink flow paths  46  and  48 . Arrows  1  and  2  in  FIG. 15  show the direction of movement of the mold inserts  182  and mold core  188 , respectively from the solidified cartridge body  12 . In this case, mold insert  182  is removed from the cartridge body  12  and mold core  188  before the mold  184  is opened along the direction of arrow  2  by moving mold core  188  and bottom section  186  away from each other. Once insert  182  is removed from the mold  184  and the mold  184  is opened, the solidified ink cartridge body  12  can be separated from the mold  184 . 
   A mold  200  having a bottom section  202  and mold core  204  for forming an ink cartridge  60  according to the second embodiment of the invention is provided in FIG.  16 . In this embodiment, the ink flow paths  66  and  68  are formed by a mold insert  206  inserted from the printhead area  28  side of the ink cartridge  60 . Mold segments, such as segment  208  attached to the upper section  210  of the mold core  204  form ink chambers  40  and  42  and mold segment  212  forms ink chamber  38  and ink flow path  44 . Once the cartridge body  62  has solidified, the insert  206  is removed from the solidified cartridge body  62  along the direction of arrow  1 , then the cartridge body  62  is removed from the mold  200  by opening the mold  200  along the direction of arrow  2 . 
     FIG. 17  illustrates a mold  230  for forming the ink cartridges  80  according to the third embodiment of the invention. In this case, the mold  230  includes a lower section  232  and a mold core  234  provided by an upper section  236  and a pending segment  238  attached to the upper section for forming ink chamber  100  and ink flow path  102 . In this case, a mold insert  240  also has a pending segment  242  for forming the ink chambers  88  and  90  and ink flow paths  96  and  98 . Once, the cartridge body  82  has solidified, the mold insert  238  is preferably removed through an aperture  244  in the mold core  234  along the direction of arrow  1  before the mold  230  is opened. The mold  230  is opened by separating the upper section  236  and lower section  232  from one another along the direction of arrow  2 , then the cartridge body  82  is removed from the mold  230 . 
     FIG. 18  is an illustration of a variation on mold  230  for forming ink cartridges  110  according to the fourth embodiment of the invention. As before, mold  250  includes a lower section  252  and a mold core  254 . The mold core  254  has an upper section  256  and pending segment  258  attached to the upper section for forming ink chamber  118  and ink flow path  128 . A mold insert  260  having a pending segment  262  is inserted and removed through an aperture  264  in the mold core  254  and is used to form the ink chambers  114  and  116  and ink flow channels, such as channel  124 , for ink cartridge  110 . Once the cartridge body  112  has solidified, the mold insert  260  is removed along the direction of arrow  1  through the aperture  264  in the mold core  254  preferably before the mold  250  is opened along the direction of arrow  2 , then the solidified cartridge body  112  is separated from the mold  250 . 
     FIGS. 19-22  illustrate an alternative design of an ink cartridge  270  having curved or arcuate ink flow paths  272  and  274  from filter towers  276  and is  278  in ink flow chambers  280  and  282  to the printhead area  284 . The arcuate ink flow paths  272  and  274  are formed during the molding process by a mold insert  286  (FIGS.  21  and  22 ). In this embodiment, the ink flow paths  272  and  274  may be formed without changing the shape or size of the ink chambers  280  and  282 . Ink chamber  288  and ink flow path  290  are formed generally as described above with reference to 1-3. 
   The mold for forming the ink cartridge  270 , according to this embodiment is similar to the mold  184  ( FIG. 15 ) with the exception that the top section or mold core also contains an arcuate opening therein for positioning the mold inserts  286  in the mold during the molding process. The mold inserts  286  are located on the core side of the tooling. During the molding process, the mold insert  286  is actuated or rotated into position ( FIG. 22 ) for forming the ink flow paths  272  and  274 . After molding the ink cartridge  270 , the mold inserts  286  are retracted to a position as shown in FIG.  21  and the mold core and lower section of the mold are moved away from each other so that the ink cartridge  270  may be separated from the mold. 
   After the ink cartridges  10 ,  60 ,  80 ,  110 ,  140 , and  270  are formed in the molds described above, the thermoplastic material forming the cartridges is cooled to solidify the material and the cartridges are removed from their respective molds. A printhead chip and corresponding flexible circuit is attached to the cartridge bodies. Next, the ink chambers may be filled with a capillary material, such as foam, and/or ink in the absence of a capillary material and a cover is attached by adhesives or thermoplastic welding to the open-topped body of the ink cartridge to provide a closed container. 
   It is contemplated, and will be apparent to those skilled in the art from the preceding description and the accompanying drawings, that modifications and changes may be made in the embodiments of the invention. Accordingly, it is expressly intended that the foregoing description and the accompanying drawings are illustrative of preferred embodiments only, not limiting thereto, and that the true spirit and scope of the present invention be determined by reference to the appended claims.