JP5440264B2 - Ink cartridge and image forming apparatus - Google Patents

Description

  The present invention relates to an ink cartridge and an image forming apparatus that is detachably equipped with an ink cartridge.

  2. Description of the Related Art As an image forming apparatus such as a printer, a facsimile machine, and a copying machine, an ink jet type using a recording head that discharges ink droplets is known. Such a liquid discharge recording type image forming apparatus forms an image by discharging ink droplets from a recording head onto a transported recording medium (hereinafter sometimes simply referred to as “paper”). A serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head are used. There is a line type image forming apparatus.

  In such an image forming apparatus (hereinafter, also simply referred to as “inkjet recording apparatus”), for example, a sub tank for supplying ink to the recording head is mounted on a carriage on which the recording head is mounted, and the main ink cartridge is used as the image forming apparatus. A device that is detachably mounted on a main body (hereinafter sometimes simply referred to as “device main body”) and that supplies ink to a sub tank from an ink cartridge on the device main body side is known.

  As such an ink cartridge, a double bag provided with an outer bag portion for introducing compressed air to the outside of an ink bag serving as an inner bag portion is accommodated in a cartridge case, and air is introduced into the outer bag portion. In this type, an ink bag is pressurized and ink is supplied to the recording head side.

  In this pressure type ink cartridge, a high pressure is applied to the cartridge case. Moreover, in recent years, the pressure for pressurizing the cartridge tends to be further increased in order to increase the amount of liquid feeding in order to cope with an increase in printing speed, or to feed ink with quick drying and high viscosity.

  As a conventional ink cartridge, for example, a thin, substantially rectangular parallelepiped cartridge case containing an ink pack is provided, and the cartridge case includes a main body portion and a lid portion (Japanese Patent Laid-Open No. 2006-82290) (Patent Document 1). ).

  Also, Japanese Patent Publication No. 2002-505212 (Patent Document 2) proposes that ink is contained in a bottle-shaped case by blow molding.

  However, the ink cartridge is required to have a large capacity in order to cope with an increase in image forming speed and to be able to stably supply ink. In the ink cartridge disclosed in Patent Document 1 described above, the cartridge case is divided. Since the surface is divided into two surfaces having the largest area among the six surfaces and a parallel surface, a large load is applied to the divided surface of the case during pressurization. May be damaged.

  Further, the cartridge using the bottle-shaped case by blow molding disclosed in Patent Document 2 increases the pressure resistance by reducing the mouth of the bottle-shaped case. Cannot be put into the case or is very difficult.

  The present invention solves the above-described problems in conventional ink cartridges, and provides an ink cartridge that has a structure that does not break even when high pressure is applied, and that is excellent in assemblability, and an image forming apparatus including the ink cartridge. This is the issue.

  According to the present invention, a double bag comprising an inner bag filled with ink and an outer bag for accommodating the inner bag is accommodated in a cartridge case, and gas is introduced into the outer bag. An ink cartridge that pressurizes the inner bag to supply ink in the inner bag to the outside of the cartridge, and the cartridge case is a cylindrical shape in which a portion to which pressure is applied by introducing gas into the outer bag is integrally molded A front cover for closing the front opening of the cylindrical container main body portion and a rear cover for closing the rear opening, and the double bag is The problem is solved by an ink cartridge configured as a chamfered portion in which both side corners in the width direction on the front side in the insertion direction when the heavy bag is inserted into the container main body from the rear opening are chamfered.

  Further, the double bag is configured as a chamfered portion in which both end corners on the rear side in the insertion direction when the double bag is inserted into the container main body from the rear opening are also chamfered. It is preferable.

Further, it is preferable that the chamfered portion is connected to the chamfered portion and the outer portion thereof by a curved connecting portion.
In addition, the chamfered portion has a size in a direction perpendicular to an insertion direction when the double bag is inserted into the container main body portion from the rear opening, and a size in a direction parallel to the insertion direction is L2. Is preferably provided so as to satisfy the relationship of L1 <L2.

  Further, according to the present invention, a double bag comprising an inner bag filled with ink and an outer bag for accommodating the inner bag is accommodated in the cartridge case, and gas is introduced into the outer bag. An ink cartridge that pressurizes the inner bag to supply the ink in the inner bag to the outside of the cartridge, and the cartridge case is integrally formed with a portion to which pressure is applied by introducing gas into the outer bag It is configured to be held by a cylindrical container body, and has a front cover that closes the front opening of the cylindrical container body, and a rear cover that closes the rear opening. This is solved by an ink cartridge in which two sides located on both sides in a direction orthogonal to the insertion direction when the double bag is inserted into the container main body from the rear opening are configured as curved portions.

Further, it is preferable that the curved portion is a part of an arc.
Moreover, it is preferable that the two sides configured as the curved portion are connected to the front side and the rear side in the insertion direction by a curve.

  In addition, according to the present invention, the above problem is solved by an image forming apparatus in which the ink cartridge according to any one of claims 1 to 6 is detachably mounted.

  According to the ink cartridge of the first aspect and the ink cartridge of the fifth aspect, since the cartridge has a strong structure that does not break even when a high pressure is applied, the ink can be stably supplied. It is possible to provide an ink cartridge that is easy to insert a heavy bag and excellent in assembling.

  According to the configuration of claim 2, the corners at both ends on the rear side in the insertion direction are also chamfered, so that the double bag is not caught when the rear cover is attached, and the assemblability can be further improved.

  According to the configuration of claim 3, since the chamfered portion and the outer portion thereof are communicated with each other by the curved connecting portion, the double bag can be more easily inserted, and the assemblability can be further improved.

According to the configuration of the fourth aspect, since the inclination of the chamfered portion is increased, the double bag can be easily inserted, and the assemblability can be further improved.
According to the configuration of the sixth aspect, the double bag can be easily inserted into the cartridge case.

According to the configuration of the seventh aspect, the double bag can be more easily inserted, and the assemblability can be further improved.
According to the image forming apparatus of the eighth aspect, it is possible to supply a stable ink by using an ink cartridge having a high strength, to realize a stable image formation, and to cope with an increase in the image forming speed. it can.

1 is an external perspective view of a color inkjet printer which is an example of an image forming apparatus according to the present invention. It is a top view of the printing mechanism part of the inkjet printer. It is a perspective view which shows a carriage and a maintenance recovery mechanism part. It is a schematic diagram for demonstrating an ink supply system. 2 is an external perspective view of an ink cartridge. FIG. It is a perspective view of the ink cartridge seen from the opposite side. 2 is an exploded perspective view of an ink cartridge. FIG. It is a perspective view of a cartridge base. It is a disassembled perspective view of the front cover of a cartridge. It is a perspective view of the front cover seen from the other side. It is a perspective view of the double bag which is an ink container. It is a perspective view which shows the spout of a double bag. FIG. 3 is a plan sectional view of an ink cartridge. It is a perspective view which shows an example of the conventional ink container. It is a perspective view which shows 1st Example of a double bag. It is a perspective view which shows 2nd Example of a double bag. It is a perspective view which shows 3rd Example of a double bag.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view of a color inkjet printer which is an example of an image forming apparatus according to the present invention. FIG. 2 is a plan view of the printing mechanism of the ink jet printer. FIG. 3 is a perspective view showing the carriage and the maintenance / recovery mechanism.

  The ink jet printer of this example shown in these drawings is a serial type ink jet recording apparatus. Inside the recording apparatus main body 1, guide rods 3 and guide rails 4 are spanned on both side plates (not shown). The carriage 5 is held on the guide rail 4 so as to be slidable in the main scanning direction. The guide rail 4 is configured such that a sub-guide roller 6 rotatably supported on the rear portion of the carriage 5 comes into contact therewith.

  A main scanning mechanism that moves and scans the carriage 5 is disposed on one side in the main scanning direction, a driving pulley 12 that is rotationally driven by the driving motor 11, and on the other side in the main scanning direction. A driven pulley 13 and a timing belt (belt member) 14 wound around the drive pulley 12 and the driven pulley 13 are provided. The driven pulley 13 is tensioned outward (in a direction away from the drive pulley 12) by a tension spring.

  Here, the driving pulley 12 and the driven pulley 13 are arranged such that the pulley axial direction is located in a direction along the ink droplet ejection direction. The belt member 14 hung between the driving pulley 12 and the driven pulley 13 is partly fixed and held by a belt fixing portion provided on the back side of the carriage 5 so that the main scanning direction can be obtained. It is arranged on one side of the carriage 5 in the orthogonal direction.

  Further, the carriage 5 has ten buffer tanks (sub tanks) including liquid discharge heads having nozzles for discharging ink droplets of black (K), yellow (Y), magenta (M), and cyan (C). The attached recording heads 20a to 20j (referred to as “recording head 20” when not distinguished from each other) are arranged on a head base (not shown). Here, the recording heads 20a and 20b and the recording heads 20c and 20d are used in a staggered arrangement with their positions shifted in the paper conveyance direction, for example, as heads that eject black ink droplets. The recording heads 20e to 20g and the recording heads 20h to 20j are staggered by shifting the positions in the paper conveyance direction. For example, the recording heads 20e and 20h have cyan ink droplets, and the recording heads 20f and 20i have magenta ink droplets. The recording heads 20g and 20j are used as heads for ejecting yellow ink droplets, respectively, so that the area in the paper feeding direction for two heads can be printed by the same main scanning.

  On the other hand, in the main scanning area of the carriage 5, in the recording area, the paper 10 is intermittently conveyed by being guided by the platen member in a direction (sub-scanning direction) perpendicular to the main scanning direction of the carriage 5 by a paper feed mechanism (not shown). Is done. The platen member is disposed to face the recording head 20 at least in the recording area along the main scanning area of the carriage 5.

  In addition, a maintenance / recovery mechanism 8 that performs maintenance / recovery of the recording head 20 is disposed in one end side region of the main scanning region. The maintenance / recovery mechanism 8 includes a cap 30 that seals (capping) each nozzle surface of the recording heads 20a to 20j, a wiper member that wipes a nozzle surface (not shown), and the like.

  Further, as shown in FIG. 1, an ink cartridge (main tank) 200 containing ink of each color to be supplied to the recording head 20 is detachably mounted outside one main scanning area.

  In the ink jet recording apparatus configured as described above, the carriage 5 is moved in the main scanning direction, and the recording head 20 is driven according to the image information while the paper 10 is intermittently fed in the sub scanning direction, thereby ejecting droplets. By doing so, a required image is formed on the paper 10.

FIG. 4 is a schematic diagram for explaining an ink supply system in the inkjet recording apparatus 1.
In FIG. 4, a recording head 20 including a head portion 21 composed of a liquid discharge head that discharges droplets and a buffer tank (sub tank) 22 that supplies ink to the head portion 21, and a main that stores ink to be supplied to the recording head 20. A replaceable ink cartridge 200 as a tank is provided, and ink is replenished and supplied from the ink cartridge 200 to the buffer tank 22 through the supply tube 24 according to the ink consumption of the recording head 20.

  The ink cartridge 200 includes an ink bag 202 that is an inner bag for containing the ink 300 in the cartridge case 201, and an ink bag 202 that contains the ink bag 202 therein, and gas (here, air) is introduced thereinto. A double bag 204 comprising an air bag 203 as an outer bag for supplying the ink 300 in the ink bag 202 to the outside of the ink cartridge 200 by pressurizing the bag 202 is provided, and air is introduced into the air bag 203 by the pump 25. By pressurizing the ink bag 202, the ink 300 is supplied to the recording head 20 side. The supply tube 24 and the ink bag 202 are detachably connected by the hollow needle 400, and the pump 25 and the air bag 203 are detachably connected by the air joint unit 500.

  FIG. 5 is an external perspective view of the ink cartridge. FIG. 6 is a perspective view of the ink cartridge as viewed from the side opposite to FIG. FIG. 7 is an exploded perspective view of the ink cartridge. FIG. 8 is a perspective view of the cartridge base. FIG. 9 is an exploded perspective view of the front cover of the cartridge. FIG. 10 is a perspective view of the front cover as viewed from the side opposite to FIG. FIG. 11 is a perspective view of a double bag that is an ink container. FIG. 12 is a perspective view showing a double bag spout. FIG. 13 is a plan sectional view of the ink cartridge.

  As shown in these drawings, an ink cartridge 200 includes an ink bag 202 that stores ink in a cartridge case 201 that is a storage container, and an ink bag 202 that stores the ink bag 202 therein, and gas is introduced into the ink cartridge. A double bag 204 is housed as an ink container including an air bag 203 that pressurizes the bag 202 and supplies the ink in the ink bag 202 to the outside of the ink cartridge 200.

  The double bag 204 is composed of an ink bag 202 and an air bag 203, and an ink bag 202 on the inside and an air bag 203 on the outside are thermally welded to a spout 241 that is an engagement member made of resin such as polyethylene. It is fixed. The spout 241 includes an ink supply port 242 for supplying ink to the apparatus main body, an ink filling port 243 used in the ink filling process in the ink bag 202, and air (gas) for pressurization. An air inlet 244 used for introduction into the bag 203 is provided.

  The ink supply port 242 is internally provided with a rubber seal 245, and the hollow needle 400 on the apparatus body side penetrates the rubber seal 245 and communicates with the inside of the ink bag 202. Even if the ink cartridge 200 is removed from the apparatus main body 1 with the ink remaining, the rubber seal 245 is elastically restored and closes the portion where the hollow needle 400 is inserted, so that the ink stored in the ink bag 202 is retained in the ink cartridge. It will not leak out of the 200.

  The ink filling port portion 243 communicates with the inside of the ink bag 202, and after being filled with ink, is sealed on the way by thermal welding. When filling ink, the inside of the ink bag 202 is once evacuated, so that the ink bag 202 is crushed by two flat plates in order to keep the ink bag 202 in a flat state. By sucking air from the portion 243 and filling it with ink, it is possible to minimize unnecessary air from being put into the ink in the ink bag 202.

  The air introduction port portion 243 communicates with the outside of the ink bag 202 inside the air bag 203, and introduces pressurized air from the apparatus main body during printing to press the ink bag 202 in the compression direction.

  On the other hand, the cartridge case 201 which is a storage container for storing the double bag 204 is a base 211 which is a cylindrical container main body for storing the double bag 204 and before the opening 222 in front of the container main body 211 is closed. The cover 212 and the rear cover 213 that closes the opening 223 at the rear of the container main body 211 are constituted by three parts.

  In this example, the front cover 212 is provided with a protrusion 251, the base 211 is provided with a recess 252, and the front cover 212 and the base 211 are positioned by fitting the concave and convex portions. The holes 253 and 254 are fixed with screws. The fastening method of the base 211 and the rear cover 213 is fixed by any one or a plurality of methods such as screwing, snap fitting, welding, and adhesion.

  Here, the opening 222 in front of the base 211 is a part of the cylindrical portion of the base 211 and has an opening of a size that exposes at least the entire spout mounting portion 214 as an attachment portion described later. . Further, the rear opening 223 has an opening having a size that allows the entire cylindrical portion of the base 211 to be opened. The rear opening 223 is also an opening having a size that allows the base 211 to be removed from the mold when the base 211 is formed by injection molding.

  All of the three parts, the base 211, the front cover 212, and the rear cover 213 constituting the cartridge case 201, are formed by injection molding (integral molding) with a resin such as polystyrene or ABS. Considering the recyclability of the material, it is preferable to form all three parts from the same material, but it is also possible to form only the base 211 to which the load is most applied during pressurization from a high-strength resin.

  The base 211 is provided with a spout mounting portion 214 that is a mounting portion for attaching the spout 241 of the double bag 204, and the spout mounting portion 215 that is a mounting portion for mounting the spout 241 of the double bag 204 is also provided on the front cover 212. It has been. By attaching the front cover 212 to the base 211, the spout 241 is fixed at the spout mounting portions 214 and 215. In a state where the front cover 212 is set on the base 211, holes 216 and 217 are formed in the cartridge case 201 at portions corresponding to the supply port portion 242 and the air introduction port portion 243. The needle 400 and the air joint 500 are connected to allow access from the apparatus main body.

  Further, the cartridge case 201 composed of the three parts of the base 211, the front cover 212, and the rear cover 213 has the front side portion 255 and the rear side portion 256 deformed inward in accordance with the outer shape of the double bag 204. It is formed in a different shape. Further, reinforcing ribs 257.258 are formed on the outer surface side of the front portion 255 on the base 211 and the front cover 212, respectively, so that the structure is difficult to be deformed when pressurized. Note that the inner wall surface of the cartridge case 201 is formed in a smooth shape without irregularities so as not to damage the double bag 204 when dropped.

  Further, an ID chip 261 is fixed to the front surface of the front cover 212 (the front surface when mounted on the apparatus main body) by heat welding or double-sided tape. Further, the front cover 212 is integrally formed with a color non-compatible rib 262 corresponding to the color of the accommodated ink, and the position of the rib 262 differs depending on the color, thereby preventing a color mistake at the time of mounting.

  The front cover 212 is integrally formed with a positioning rib 263 with the apparatus main body, and the rib 263 extends from the front cover main body 212a closing the opening 222 of the base 211 in the rear cover direction in parallel with the mounting direction. Is provided. Thus, since the positioning rib 263 has a shape extending further rearward than the front cover main body 212a, the positioning with the apparatus main body becomes more reliable.

  The cartridge case 201 (particularly the base 211 and the front cover 212) formed of three parts is deflated at the front side and the peripheral portion reinforced by the ribs 257 and 258 is the amount of deformation during pressurization. Less is. For this reason, positioning with respect to the main body of the apparatus, positioning of the ID chip 261 and spout 241 and the position of the color non-compatible rib 262 are important, and components or parts having a low tolerance for deformation are concentrated on the base 211 and the front cover 212. Are preferably arranged.

  In this case, the front cover 212 is less deformed when pressurized than the base 211. Therefore, the front cover 212 is positioned with the apparatus body, the ID chip 261, the spout 241 and the color non-compatible rib 262. More preferably.

  That is, by configuring the front cover 212 to close the opening 222 of a part of the base 211, the strength of the front cover 212 is increased, and it is not necessary to make a thick case in order to avoid deformation due to pressure, The pressure during pressurization can be received while achieving the necessary positioning efficiently.

  When assembling the ink cartridge 200 configured as described above, the double bag 204 filled with ink is inserted from the rear opening 223 of the base 211 of the cartridge case 201, and the spout 241 of the double bag 204 is inserted into the spout of the base 211. The spout 241 of the double bag 204 is fixed at the spout mounting portion 215 of the front cover 212, and then the rear of the base 211. The rear cover 213 is attached to the opening 223. Thereby, the double bag 204 containing the deaerated ink can be stored in the cartridge case 201.

  In the present embodiment, the ink cartridge 200 is configured as described above, so that it is not necessary to use a thick case to avoid deformation, and the pressure at the time of pressurization can be achieved while efficiently achieving the necessary positioning. This realizes a durable ink cartridge that can accept the problem.

Here, an example of a conventional ink container will be described with reference to FIG.
The double bag 104 includes an ink bag 102 and an air bag 103, and a spout 141 is attached. The four corners of the air bag 103 are corners C. As can be seen from FIG. 14, since the double bag 104 has the ink bag 102 contained in the air bag 103, the air bag 103 projects over the outer portion of the ink bag 102 (in three directions other than the spout mounting portion). It has a different shape. When the double bag 104 having such a shape is set in the cartridge, the overhanging portion of the air bag 103, in particular, the corners C and shoulders on both sides in the width direction on the front side in the insertion direction come into contact with the case and become an obstacle. The double bag finally contained in the case is in a state in which the air bag overhanging portions on both sides in the width direction are folded (see FIG. 7). The shoulder portion comes into contact with the case.

  Therefore, in the double bag 204A according to the present invention shown in FIG. 15 (first embodiment), the four corners of the air bag 203 which is the outer bag of the double bag are obliquely chamfered to constitute a chamfer M. Both side portions of the chamfered portion M are configured as curved connecting portions R in which the sides connected to the chamfered portion M are connected in a curved shape. Accordingly, when the double bag 204A is inserted into the cartridge from the rear opening 223 of the base 211, it can be smoothly inserted into the case (base 211), and the assembly property of the ink cartridge can be improved. .

  In the double bag 204A of this embodiment, all four corners of the air bag 203 are chamfered portions M, but at least the corners on the front side in the insertion direction (the direction perpendicular to the insertion direction on the front side in the insertion direction = both sides in the width direction) The corners) may be configured as the chamfered portion M. However, if the corner on the rear side in the insertion direction is also the chamfered portion M, the rear cover 213 is not caught by the absence of the corner on the rear side, and the assemblability can be improved in this respect. Of course, it is preferable that both side portions of the chamfered portion M on the rear side are configured as the curved connecting portion R.

  FIG. 16 is a perspective view showing a second embodiment of the double bag according to the present invention. In the double bag 204B shown in this figure, the four corners of the air bag 203 are configured as chamfered portions M, and that both side portions of the chamfered portion M are configured as curved connecting portions R are shown in FIG. This is the same as the double bag 204A of the first embodiment.

  In addition, in the double bag 204B of the second embodiment, the dimension of the chamfered portion M is L1 in the direction (width direction) orthogonal to the direction of insertion into the cartridge (from the bottom to the top in the figure). When the size in the direction parallel to the insertion direction (length direction) is L2, the relationship is set so that L1 <L2. As a result, the inclination of the inclined surface of the chamfer M is increased (the angle α with respect to the direction orthogonal to the insertion direction is 45 degrees or more), so that the double bag 204B can be more easily inserted into the cartridge case (base 211). Thus, the assembling property of the ink cartridge can be improved.

  Also in this embodiment, at least the chamfered portion M on the front side in the insertion direction should satisfy L1 <L2, but the rear chamfered portion M on the rear side in the insertion direction can be easily covered with the rear cover 213. Also in this respect, the assembling property can be improved.

  FIG. 17 is a perspective view showing a third embodiment of the double bag according to the present invention. In the double bag 204C shown in this figure, sides K and K located on both sides in the direction (width direction) perpendicular to the direction of insertion into the cartridge (from the bottom to the top of the figure) are configured as curved portions, In addition, the sides K, K and the front side and the back side in the insertion direction are connected by a curve. Note that the sides K and K configured as the curved portion may be formed as a part of an arc.

  With such a configuration, the double bag 204C of the third embodiment can be smoothly inserted into the case (base 211) of the cartridge, and the rear cover 213 can be easily covered to improve the assembling property of the ink cartridge. Can be made.

  As described above, the ink cartridge of the present embodiment is a cartridge having a durable structure that does not break even when a high pressure is applied by adopting the cartridge configuration as described above. By using the double bag 204, since the setability of the double bag as the ink container is excellent, it is possible to provide an ink cartridge that achieves both high strength and excellent assemblability.

  Further, in the image forming apparatus using the ink cartridge of the present embodiment, it is possible to supply a stable ink by using an ink cartridge having a high strength, so that a stable image formation can be realized and the image forming speed can be increased. Can also respond.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the shape or the like of the double bag that is the ink container can be appropriately changed within the scope of the present invention. Further, the configuration of each part of the ink cartridge can be changed as appropriate. Of course, the color of the ink to be stored is arbitrary. The ink cartridge according to the present invention can be used not only in the serial type image forming apparatus of the illustrated example but also in a line type image forming apparatus in which the recording head does not move.

  Further, the number of ink colors and the number of ink cartridges in the ink jet recording apparatus are arbitrary. Further, the present invention can be applied not only to a color image forming apparatus but also to a monochrome apparatus. Further, the image forming apparatus is not limited to a printer, and any form such as a copying machine, a facsimile machine, or a multifunction machine having a plurality of functions can be adopted.

DESCRIPTION OF SYMBOLS 1 Recording device main body 5 Carriage 8 Maintenance recovery mechanism 20 Recording head 24 Ink supply tube 200 Ink cartridge 201 Cartridge case 202 Ink bag (inner bag)
203 Air bag (outer bag)
204 Double bag 211 Base 212 Front cover 213 Rear cover 213
223 Opening 241 Spout 300 Ink 400 Hollow needle 500 Air joint part

JP 2006-82290 A Special Table 2002-505212

Claims (8)

A double bag consisting of an inner bag filled with ink and an outer bag containing the inner bag is accommodated in the cartridge case, and the inner bag is pressurized by introducing gas into the outer bag. An ink cartridge that supplies ink in the inner bag to the outside of the cartridge,
The cartridge case is configured to hold a portion to which pressure is applied by gas introduction into the outer bag with an integrally formed cylindrical container body, and closes an opening in front of the cylindrical container body. Having a front cover and a rear cover that closes the rear opening;
The double bag is configured as a chamfered portion in which both corners in the width direction on the front side in the insertion direction when the double bag is inserted into the container body from the rear opening are chamfered in a slope shape. An ink cartridge characterized by that.   The double bag is configured as a chamfered portion in which both corners on the rear side in the insertion direction when the double bag is inserted into the container main body from the rear opening are also chamfered in a slope shape. The ink cartridge according to claim 1, wherein the ink cartridge is characterized.   3. The ink cartridge according to claim 1, wherein the chamfered portion is connected to the chamfered portion and an outer portion thereof by a curved connecting portion.   In the chamfered portion, the size in the direction orthogonal to the insertion direction when the double bag is inserted into the container main body portion from the rear opening is L1, and the size in the direction parallel to the insertion direction is L2. The ink cartridge according to any one of claims 1 to 3, wherein the ink cartridge is provided so as to satisfy a relationship of L1 <L2. A double bag consisting of an inner bag filled with ink and an outer bag containing the inner bag is accommodated in the cartridge case, and the inner bag is pressurized by introducing gas into the outer bag. An ink cartridge that supplies ink in the inner bag to the outside of the cartridge,
The cartridge case is configured to hold a portion to which pressure is applied by gas introduction into the outer bag with an integrally formed cylindrical container body, and closes an opening in front of the cylindrical container body. Having a front cover and a rear cover that closes the rear opening;
In the double bag, two sides positioned on both sides in a direction orthogonal to the insertion direction when the double bag is inserted into the container main body from the rear opening are configured as curved portions. Ink cartridge.   The ink cartridge according to claim 5, wherein the curved portion is a part of an arc.   The ink cartridge according to claim 5, wherein the two sides configured as the curved portion are connected to the front side and the rear side in the insertion direction by a curve. An image forming apparatus, wherein the ink cartridge according to claim 1 is detachably mounted.

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