Abstract:
A method of constructing an ink cartridge is disclosed. The method comprises the steps of: providing an ink bag with an ink supply port at one end and an ink charge opening at an opposite end thereof; then affixing a back member to an external flat side of the ink bag; then suspending the ink bag with the ink supply port facing downward and charging a predetermined amount of ink into the ink bag via the ink charge opening; then permanently sealing the ink charge opening; keeping the ink bag flat with the back member; and affixing the back member to the bottom of a case main body.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 08/946,461 filed Oct. 7, 1997, now U.S. Pat. No. 6,053,606. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to an ink cartridge that supplies ink to a recording head, and, in particular, to an improvement in the protection of the ink bag of an ink cartridge wherein the ink bag is accommodated in a case main body along with an ink depletion detecting plate affixed to the ink bag. 
     Generally an ink jet recording apparatus is designed to print data by causing the recording head thereof to reciprocally move along the width of a recording sheet. Ink is supplied from an ink supply source to the recording head. As a result of such a construction, an ink jet recording apparatus that must produce a large number of copies must carry a large-sized ink cartridge, which cannot be mounted on a carriage. Hence, the ink cartridge is mounted on the housing of the recording apparatus and the ink is supplied to the recording head through a tube. 
     Reference is made to FIG. 16 in which an example of such a prior art ink jet recording apparatus is shown. A case main body  63  contains an ink bag  62  which includes an ink supply port  64 . Ink cartridge  61  is connected via a tube  65  to a sub tank  66  located on a carriage  67 . In this manner, ink can be supplied from the sub tank  66  to a recording head affixed to a lower surface of the carriage  67 . The apparatus housing  60  also contains a waste ink tank  70 . 
     Supplying the ink in this manner significantly increases the number of copies that can be printed by using only one cartridge as compared with the case where the ink cartridge is mounted on the carriage. However, the large size of the ink cartridge results in a large recording apparatus, which is a problem. 
     Unexamined Japanese Patent Publication No. Hei. 5-16378 discloses the design of such an ink cartridge. An ink depletion detecting plate  69  (FIG. 17) is secured to the upper surface of the flexible ink bag  62  to cover part of the upper surface of the ink bag. The ink depletion detecting plate has a detecting piece which projects out from a side thereof and aligns with a window located in the case main body. A displacement of this detecting piece is sensed by an ink end detector disposed on the main body of the recording apparatus. 
     In an effort to overcome this problem, the ink bag  62  has been accommodated in a housing  60  in such a manner that a side surface along the length of the ink bag  62  extends vertically with respect to the corresponding side surface of the housing  60 , thereby decreasing the area needed to mount the ink cartridge  61  which results in the desired downsizing of the recording apparatus. Additionally, the size of the ink bag is increased to use any dead space within the housing which results in an increase in the ink capacity of the recording apparatus. 
     The prior art ink bag has been satisfactory. However, an increase in the size of the ink bag results in an increase in the area that is not covered by the ink depletion detecting plate. Subsequently, when the ink bag is subjected to vibrations during transportation or if the ink cartridge is dropped, the area of the ink bag  62  not covered by the ink depletion detecting plate  69  is shaken at a large amplitude. This results in the collision of the uncovered area of the ink bag with the side walls of the case main body. The uncovered area of the ink bag can also be subjected to bending, twisting or rubbing of the ink bag boundary with the ink depletion detecting plate. Consequent damage to the ink bag can result in the breaking of the bag or impairment of its air shielding characteristics. 
     Further, to prevent deformation of the ink bag and thereby ensure stable, consistent discharge of ink to the recording head, the shape of the ink bag is maintained by securing a flat area of the ink bag to the bottom on the case main body  63 . Additionally, this attachment prevents damage to the ink bag  62  during transportation. 
     However, in some cases, shaking of the ink at the time when the bottom, flat surface of the ink bag is affixed to the case main body with an adhesive  68 , results in the creation of wrinkles on the thus attached surface of the ink bag. These wrinkles extend parallel with the short side of the rectangular ink bag. Moreover, ink bags prepared by using a thick film to increase air shielding characteristics have wrinkles that do not collapse. These wrinkles cause problems with the flow of the ink resulting in the blockage of the ink to the ink supply port  64  which in turn causes the ink to stagnate in the ink bag. Additionally, the wrinkles cause the ink depletion detecting plate to float by a certain height G from the bottom of the ink cartridge. This condition persists even when there is no more ink left in the ink bag thus preventing the accurate detection of an ink end. 
     SUMMARY OF THE INVENTION 
     Generally speaking in accordance with the invention, an ink cartridge includes a case main body. A flat flexible ink bag is formed so as to be substantially rectangular and has an ink supply port formed on a short side thereof. An ink depletion detecting plate is fixed to one of the flat regions of the ink bag and has an outwardly projecting detecting piece. Another flat region of the ink bag is fixed to a bottom of the case. A cover covers an opening of the case main body. In an exemplary embodiment, the ink depletion detecting plate has projecting pieces on at least one long side thereof, the projecting pieces being such as to extend outward beyond an outer edge of the ink bag and such as to allow front ends thereof to come in contact with a side wall of the case main body. 
     A projecting piece extending outward beyond an outer edge of the ink bag is formed at least on a single side of the ink depletion detecting plate. The projecting piece is a short distance from said case to come in contact with the side wall of the case main body at a short stroke of the ink depletion detecting plate. Short stroke length is defined as a distance short enough in length to prevent vibration in the ink bag when the cartridge is shaken, dropped or the like. As a result, the amount of deformation of the ink bag during transportation or the like can be suppressed as much as possible. 
     Accordingly, it is an object of this invention to provide an improved ink cartridge capable of preventing damage to the ink bag due to shaking, accidental dropping and other such actions during the distribution process. 
     Another object of the invention is to provide an improved ink cartridge capable of reliably discharging ink by preventing the wrinkling of the ink bag where it is attached to the case main body. 
     Still another object of the invention is to provide an improved ink cartridge capable of correctly detecting ink depletion by preventing the wrinkling of the ink bag where it is attached to the case main body. 
     A further object of the invention is to provide an improved ink cartridge capable of keeping the amount of deformation of the ink bag to a minimum thereby protecting the ink bag from damage during transportation. 
     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 several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, 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 had to the following description taken in connection with the accompanying drawings, in which: 
     FIG. 1 is an exploded perspective view of a first embodiment of an ink cartridge constructed in accordance with the present invention; 
     FIG. 2 is a top plan view of the open ink cartridge showing an ink depletion detecting plate with the ink bag constructed in accordance with the first embodiment of the present invention; 
     FIG. 3 is a cross-sectional view taken along line A—A of FIG. 1; 
     FIG. 4 is a cross-sectional view taken along line B—B of FIG. 1; 
     FIGS.  5 (A) and  5 (B) are cross-sectional views taken along line B—B of FIG. 1, showing the relationship between the ink bag and the case main body when the ink bag and the case main body have been shaken horizontally and vertically; 
     FIG.  6 ,.is an exploded perspective view illustrating a second embodiment of an ink cartridge constructed in accordance with the present invention; 
     FIG. 7 is a cross-sectional view taken along a line C—C of FIG. 6; 
     FIG. 8 is a perspective view of a cover of the case main body constructed in accordance with a third embodiment of the invention; 
     FIG. 9 is a partially cutaway exploded perspective view of a fourth embodiment of an ink cartridge constructed in accordance with the present invention; 
     FIG. 10 is a cross-sectional view taken along line D—D of FIG. 9; 
     FIG. 11A is a diagram showing an ink bag used in the invention with no ink charged therein; 
     FIG. 11B is a diagram showing an ink bag with ink charged therein and with the opening thereof sealed; 
     FIG. 12 is a diagram showing an ink filled ink bag and case before the ink bag is placed within the case main body in accordance with the invention; 
     FIG. 13 is a sectional view showing a depleted ink bag secured to a case main body in accordance with the invention; 
     FIG. 14 is a sectional exploded view of an ink cartridge constructed in accordance with a fifth embodiment of the present invention; 
     FIG. 15 is a sectional view of an ink cartridge constructed in accordance with a sixth embodiment of the present invention; 
     FIG. 16 is a diagram showing an ink jet recording apparatus having an ink cartridge accommodated in a case in accordance with the prior art; and 
     FIG. 17 is a diagram showing an ink cartridge without any ink in an ink bag secured to a case main body in accordance with the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is made to FIG. 1 which illustrates an ink cartridge, generally indicated as  1 , constructed in accordance with a first embodiment of the invention. Ink cartridge  1  includes a case main body  30 , a flat, flexible, rectangular ink bag  10  with ink sealed therein and an ink depletion detecting plate  20 . Ink depletion detecting plate  20  has an extending detecting piece  21  on a long side thereof. The detecting piece  21  serves to operate an ink depletion detector, not shown, constructed of a light switch or similar device. Case main body  30  accommodates the ink bag  10  and the ink depletion detecting plate  20 . A cover  35  seals an open end of case main body  30 . 
     The front surface of the ink bag  10  facing the open end of the case main body  30  is affixed to ink depletion detecting plate  20  with an adhesive, a pressure sensitive adhesive double coated tape or by similar means, not shown. The rear surface of the ink bag  10  is affixed to the bottom of case main body  30  with an adhesive  34 , a pressure sensitive adhesive double coated tape, or by similar means. The adhesive is such that it allows the ink bag  10  to be released from the case main body  30 . 
     Further, in a preferred embodiment, ink bag  10  is constructed of an aluminum laminated film formed by interposing an aluminum foil between two films, e.g., a nylon film on the outer side and a polyethylene film on the inner side so that gas barrier characteristics can be ensured. The aluminum laminated film has an opening on a short side thereof. A conduit  14 , allowing a molded ink supply port  11  to be attached thereto, is attached to an opening on the short side of ink bag  10  by thermal fusion. 
     A flat region  200  of ink bag  10  forms a front surface side of the ink bag  10 , the surface facing the open end of case  30 . Positioning marks  13  are provided on flat region  200  and provide support for the ink depletion detecting plate  20 . The positioning marks  13  facilitate the positioning of the detecting piece  21  found on the ink depletion detecting plate  20  by causing the detecting piece  21  to confront a window  31  located in the bottom of the case main body  30 . 
     Further, the ink depletion detecting plate  20  is constructed of a thin plate having a rigidity such that it follows any deformation of the ink bag  10  caused by a change in the amount of ink in the ink bag  10 . The four corners of the ink depletion detecting plate  20  are chamfered to have rounded portions  23  (FIG.  2 ). Additionally, the ink depletion detecting plate has projecting pieces  22  formed at least on a long side of detecting plate  20  opposite the long side on which the detecting piece  21  is formed. The projecting pieces  22  are located at positions that allow the front ends thereof to extend beyond an outer edge  12  of ink bag  10  and come in contact with the side wall  31 A of the case main body  30 . 
     Further, as shown in FIG. 2, the width c of detecting plate  20  and the length d of detecting plate  20  are set to values that are 0.6 times or greater, or more preferably, 0.6 to 0.9 times the width C and the length D of an ink containing region of the ink bag  10  when ink bag  10  is filled with ink. c represents the short length (width) of the ink depletion detecting plate  20 , d represents the long length of the ink depletion detecting plate  20 , C represents the short length (width) of the ink bag  10 , and D represents the long length of the ink bag  10 . Additionally, the area of the ink depletion detecting plate  20  is defined to values that are 0.3 times or greater, or more preferably 0.4 to 0.8 times the area of a flat region  200  of the ink bag  10 . 
     Setting the area of the ink depletion detecting plate  20  slightly smaller than that of the ink containing region  200  of the ink bag  10 , results in the ability to smooth out any wrinkles and slack that may be formed on the ink bag  10  when there is a small amount of ink in the ink bag  10 . This in turn helps in the proper discharge of ink and allows for the correct detection of ink depletion. 
     As shown in FIG. 3, the case main body  30  has a sloped portion  32  on the bottom of case  30  at an end of case  30  on the side opposing the ink supply port  11  of ink bag  10 . This sloped portion  32  has a downward sloping surface which faces the opening of the case main body  30 . The opposite surface thereof forms a recess  33  so that the sloped portion  32  can fit the shape of a swollen portion  15  of the ink bag  10 . This arrangement within the case main body  30  allows for the attachment of the ink bag  10  to the bottom thereof with the adhesive  34  or similar means. This adhesion is made so as to be separable. 
     As shown in FIG. 4, there are a plurality of projections  36  on the back of the cover  35 . When the ink bag  10  is filled with ink, these projections  36  are substantially in contact with a front surface, facing cover  35 , of ink depletion detecting plate  20 . These projections  36  are made preferably of elastic bodies and are scattered around so as to enhance the ability of the ink depletion detecting plate  20  to coincide with the flat region of the ink bag  10 . 
     In this first embodiment, the ink cartridge  1  is assembled by affixing an ink filled ink bag  10  to the bottom of the case main body  30  with an adhesive  34  or a similar material. The four corners of the ink end detecting plate  20  are aligned with the positioning marks  13  of the ink bag  10 . The ink depletion detecting plate  20  is then secured to the exposed surface of the ink bag  10  with a pressure sensitive adhesive double coated tape or a similar material. This results in the positioning of the detecting piece  21  in alignment with and confronting the window  31  of the case main body. As a final step, the opening of the case main body  30  is sealed by affixing the cover  35  to the top of the case main body  30 . 
     FIGS. 5A and 5B depict an ink filled ink bag  10  being subjected to pressure vibrations in the directions of arrows O, P during transportation or the like. The inertia of the ink filled ink bag  10  causes the application of this force to result in the vibration of the ink bag  10  along the width of the ink bag  10 . However, since the upper surface of the ink bag  10  is fixed integrally to the ink depletion detecting plate  20  over a wide region, and since the projecting pieces  22  of the ink depletion detecting plate  20  come in contact with the side wall of the case main body  30  with extremely short displacements, the ink bag  10  is checked from shaking. 
     Further, when the ink cartridge  1  is subjected to vibrations in directions indicated by the arrows Q, in FIGS.  5 (A),  5 (B), the ink bag  10  tends to vibrate in the directions of thickness. However, the ink bag  10  has the lower surface thereof fixed to the bottom of the case main body  30  over a wide region with the adhesive  34  and has the upper surface thereof fixed over a wide region by the ink depletion detecting plate  20  that is pressed by the plurality of projections  36  arranged on the cover  35 . Therefore, the ink bag  10  is also prevented from shaking. As a result of these actions, the ink bag  10  can be reliably checked from shaking when transported or dropped. 
     Additionally, the four corners of the ink depletion detecting plate  20  come in contact with the ink bag  10  over a wide area of the rounded portions  23  as depicted in FIG.  2 . Therefore, there is no likelihood that the ink bag  10  will be damaged by scratching. 
     Further, the ink bag  10  has the ink supply port  11  fixed to the case main body  30 . The side opposite the ink supply port  11  is supported by a sloped portion  32  on the bottom of the case main body  30  as shown in FIG. 3 . The ink bag  10  has a shape regulated by the rigidity thereof. Thus, the exposed region of the ink bag  10  amounting to about 20% of the width extending between long sides of the ink depletion detecting plate  20  can be checked from being deformed wherever possible. Hence, damage caused to the ink bag  10  by bending, twisting, and rubbing that tended to occur at the boundary of the ink bag  10  with the ink depletion detecting plate  20  in the prior art can be prevented. 
     Moreover, in the prior art, when the ink cartridge  1  is attached to the recording apparatus, the ink bag  10  gets deformed. On the other hand, in the present invention, the ink depletion detecting plate  20 , which is in contact with the ink bag  10  on almost all the region, causes the ink bag to maintain a uniform shape resulting in the gradual consumption of the ink in the ink bag  10 . As a result, even with a minimal amount of ink in the ink bag  10 , the ink is discharged in a smooth manner. Additionally, such an arrangement is capable of correctly detecting an ink depletion when all the ink in the ink bag  10  is consumed. 
     Once the ink in the ink cartridge  1  has been consumed and an ink depletion is detected, the ink cartridge can be removed from the housing of the recording apparatus by hooking a finger in the recess  33  formed on the bottom of the case main body  30 . Thus, the ink cartridge  1  can be withdrawn from the recording apparatus main body with ease. 
     The ink depletion detecting plate  20  is designed so as to have substantially the same size as the flat region of the ink bag  10  in the aforementioned embodiment. If each side of the ink depletion detecting plate  20  is set to a size so as to project beyond the outer edge of the ink bag  10  toward the side wall of the case main body  30 , the projecting pieces  22  can be made as short as possible or dispensed with entirely. 
     Reference is now made to FIG. 6 in which a cartridge  100  constructed in accordance with a second embodiment of the invention is provided. Like structure is identified by like numerals. Ink cartridge  100  has a case main body  30  having a sloped portion  32 ′ on the bottom of case  30  at the side of case  30  at which the ink supply port  11  is to be positioned. Sloped portions  32 ,  32 ′ fit the shapes of the swollen portions  15  of the ink bag  10  as depicted in FIG.  7 . The case main body  30  contains the ink bag  10  therein in such a manner that the ink bag  10  is separably fixed to the bottom thereof with the adhesive  34  or a similar material. 
     Further, the cover  35  has sloped portions  37 ,  37 ′ on the bottom thereof that are disposed in confronting relationship with the sloped portions  32 ,  32 ′ formed on case main body  30 . The sloped portions  37 ,  37 ′ are provided so as to fit swollen portions  15  of the ink bag  10  facing cover  35 . The sloped portion  37  located on the opposite side of the ink supply port  11  is created by forming a recess  38  on the cover  35 , and provides an additional handle for attaching and detaching the ink cartridge  1  along with the confronting recess  33 . 
     When the ink cartridge  100  is subjected to vibrations in directions indicated by the arrows R as shown in FIG. 7, the ink bag  10  receives a force along the length thereof. Under such circumstances, the ink depletion detecting plate  20  comes in contact with the sloped portions  37 ,  37 ′ formed on the cover  35  before it can move a great distance resulting in extremely small displacements. In addition, the ink bag  10  has both surfaces thereof supported by the sloped portions  37 ,  37 ′ and  32 ,  32 ′. Therefore, the shaking of the ink bag  10  can be checked. 
     Reference is now made to FIG. 8 which shows an ink cover  135  constructed in accordance with a third embodiment of the invention. Like numerals are utilized to indicate like structures. A plurality of ribs  39 ,  39 ′ are disposed on opposed sides of cover  135  at the width (short side) of ink bag  10  so as to cover almost all the length of the short sides of ink bag  10 . This results in the formation of slopes that fit the shapes of the swollen portions  15  of the ink bag  10 . 
     Accordingly, the ribs  39 ,  39 ′ support the shapes of the swollen portions  15  of the ink bag  10  thereby checking the shaking of the ink bag  10  as a whole. Further, the absence of a recess on the cover  135  permits the surface of the cover  135  to be flat, which in turn allows for the bonding of a large adhesive label on the cover  135 . 
     Reference is now made to FIGS. 9 and 10 in which an ink cartridge, generally indicated as  300 , constructed in accordance with a fourth embodiment of the invention is shown. Like numerals are utilized to indicate like structure. Ink cartridge  300  includes a flat back member  16  secured to almost all the region of one of the flat regions of the ink bag  10 . The back member is designed so as to be fixed to the bottom of the case main body  30  with the adhesive  34 . 
     Reference is now made to FIGS.  11 (A) and  11 (B) in which charging ink bag  10  in accordance with the invention is shown. 
     Ink bag  10  has an ink charge opening  10   a  arranged therein as shown in FIG.  11 (A). The back member  16  is large enough to cover the majority of the flat surface when the ink bag  10 , with the ink filled therein, is accommodated in the case main body  30 . Back member  16  is prepared and then stuck to the surface of the ink bag  10  on the side that is fixed to case main body  30 , with the long sides of the ink bag  10  expanded, using the adhesive  34 , a pressure sensitive adhesive double coated tape, or the like. This is done before the ink is charged into ink bag  10 . 
     Next, the ink bag  10  is suspended with the ink supply port  11  facing downward, and a predetermined amount of ink is charged into the ink bag  10  in the opening  10   a . The opening  10   a  is then sealed by thermal fusion or a similar method, as shown in FIG.  11 (B). This completes the preparation of the ink bag  10 . 
     Reference is now made to FIG. 12 in which the continued assembly of ink cartridge  1  is shown. Ink bag  10  is then kept flat by one surface of the back member  16  and the other surface of the back member  16  is fixed to the bottom of the case main body  30  with the adhesive  34  or the like. Therefore, even if the ink is shaken during assembly, ink bag  10  is fixed to the case main body  30  without any wrinkling because the fixing surface of the ink bag  10  is kept flat by the back member  16 . 
     The ink cartridge  1  constructed in this manner has flat regions of the ink bag  10  that are wrinkle free and flat. Thus, the ink within the ink bag  10  is correctly discharged to the ink supply port  11 . Furthermore, upon consumption of the ink, both surfaces of the ink bag  10  are brought into intimate contact with each other without being disturbed by wrinkles as shown in FIG.  13 . Any remaining ink can be sensed by the ink depletion detecting plate  20  in accordance with the displacement of the detecting piece  21 . 
     Reference is now made to FIG. 14 in which an ink cartridge, generally indicated as  400 , constructed in accordance with a fifth embodiment of the invention is provided. Like numerals are utilized to indicate like structure. Ink cartridge  400  includes a back member  17  affixed to a flat region of ink bag  10 . A plurality of projections  18  are arranged on back member  17 . Recesses  41  are formed on the bottom of a case main body  40  so as to receive the projections  18 . As a result of this construction, the ink bag  10  can be correctly located on the case main body  40  only by positioning the projections  18  of the back member  17  with respect to the recesses  41  on the case main body  40  and engaging the former with the latter. 
     Reference is now made to FIG. 15 in which an ink cartridge, generally indicated as  500 , constructed in accordance with a sixth embodiment of the invention is provided. Like numerals are utilized to indicate like parts. Ink cartridge  500  includes a case main body  50 . A plurality of retaining members  51  are arranged on the inner side surfaces of case main body  50 . A back member  19  is secured to a flat surface of the ink bag  10  and is releasably secured to the case main body  50  by retaining members  51 . As a result of this construction, when the back member  19  is pushed into the bottom of the case main body  50 , both end portions of the back member  19  are fixed by the retaining members  51 . 
     In each of the aforementioned embodiments, the back member is bonded to the flat surface of the ink bag  10  before charging the ink into the ink bag  10 . However, the back member may be bonded to the flat region of the ink bag even after the ink has been charged into the ink bag. This can be done without any wrinkling as long as the ink bag with the ink filled therein is placed on a flat plate and tension is applied in all directions of the ink bag in order to prevent any shaking of the ink bag. 
     By providing a flat flexible ink bag that is formed so as to be substantially rectangular and that has an ink supply port formed on one short side thereof; an ink depletion detecting plate that is fixed to one flat region of the ink bag and that has an outwardly projecting detecting piece; a case main body that accommodates the ink bag while fixing the other flat region of the ink bag to the bottom thereof; and a cover that covers an opening of the case main body, and as arranging, on at least one long side of the ink depletion detecting plate, projecting pieces such as to extend outward beyond an outer edge of the ink bag and such as to allow front ends thereof to come in contact with a side wall of the case main body vibration of the ink bag may be checked. Because, the projecting pieces formed on the ink depletion detecting plate come in contact with the side wall of the case main body at short strokes, so that the ink bag can be reliably prevented from being damaged by the ink depletion detecting plate while suppressing deformation of the ink bag at the time the ink bag is subjected to vibrations due to transportation or the like the integrity of the ink bag is preserved. 
     It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above process and in the construction 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 noted 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.