JP2016175395A - Ink cartridge and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus that is able to reduce a density difference caused between recorded images in the beginning of use of an ink cartridge and those in the end of use of the ink cartridge, and that is able to shorten waiting time for recording due to agitation.SOLUTION: An ink cartridge 1 comprises a communication part that allows communication between space located outside a housing 2 and an ink storage chamber 11. The communication part 22 comprises: a communication port 8 formed in an external face of a housing; a confluent channel 200 one end of which communicates with the communication port; and a plurality of branch channels one end of each of which communicates with the confluent channel and the other end of each of which communicates with the ink storage chamber. Each branch channel comprises a first channel 210 communicating with a lower-layer area in the ink storage chamber; and a second branch channel 220 communicating with an upper-layer area. When ink flows reversely, ink flowing out from the confluent channel separately branches into a first branch channel and the second branch channel. At this time, the ratio (Q1/Q2) of ink flow rate (Q1) in the branch channel 210 to ink flow rate (Q2) in the second branch channel 220, during ink supply is smaller than that during ink reverse flow operation.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an ink cartridge capable of storing ink, and an ink jet recording apparatus that performs recording on a recording medium using ink supplied from the ink cartridge.

  As an ink used for an ink jet recording head, an ink using a pigment as a coloring material has been put into practical use. However, since the pigment is not a dissolution system such as a dye but a dispersion system, it is known that pigment particles settle in an ink cartridge storing ink.

  For example, when the ink cartridge is left in the ink jet recording apparatus for a long period of time, the pigment particles settle in the ink stored in the ink cartridge. Therefore, a concentration gradient of pigment particles occurs in the ink stored in the ink cartridge from the bottom to the top. As a result, a layer having a high pigment concentration and an excessively dark color is formed on the bottom of the ink cartridge, while a layer having an excessively light color and a low pigment concentration is formed on the top of the ink cartridge.

  Here, in the configuration in which the ink is led out from the bottom of the ink cartridge, a case where the ink cartridge is stored for a long time in a certain posture (a state in which the bottom is directed vertically downward) is considered. In this case, when ink derived from the bottom of the ink cartridge is supplied to the recording head, ink forming a layer having a high pigment concentration is supplied first, and an image having an excessively dark color is recorded. That is, there is a possibility that a density difference that can be recognized visually is produced between a recorded image recorded in the initial stage of use of the ink cartridge and a recorded image recorded in the later stage of use. Such a phenomenon becomes particularly significant in color recording in which a color image is recorded using color shading.

  As a method for solving such a problem, Patent Document 1 provides a connection part for leading out ink in the ink cartridge at the bottom of the ink cartridge, and a pipe extending vertically upward is provided at the connection part. A configuration is disclosed. This pipe is provided with a plurality of ink inlets communicating with the inside of the ink cartridge at a plurality of positions in the vertical direction, and the ink inlet located in the vertical direction has a larger inflow resistance than the other ink inlets. It has become.

  As a result, from the position where the pigment concentration is high and the position where the pigment concentration is low in the ink cartridge, an amount of ink corresponding to the ratio of the inflow resistance is caused to flow into the pipe, and the ink mixed in the pipe is formed at the lower end of the pipe A configuration to be derived is described.

  Further, Patent Document 2 discloses a liquid ejecting apparatus including another technique for eliminating a density difference generated between an image formed in the early stage of use of the cartridge and an image formed in the later stage of use. . The liquid ejecting apparatus disclosed in Patent Document 2 performs agitation by drawing the liquid in the liquid storage space into the circulation path and returning it from the circulation path to the liquid storage space, thereby achieving a uniform ink concentration in the cartridge. It has become.

Japanese Patent Laid-Open No. 2005-007855 Japanese Patent Application No. 2006-102971

  As described above, the ink cartridge described in Patent Document 1 takes out and mixes an amount of ink corresponding to the ratio of inflow resistance from a plurality of inflow ports provided in the tube. However, since the pigment concentration gradient of the ink stored in the ink cartridge varies depending on the storage period, storage posture, ink type, and the like, the pigment concentration near the inlet is not constant. Therefore, it is effective if the inside of the ink cartridge is equal to or less than a certain pigment concentration gradient, but depending on the magnitude of the pigment concentration gradient, a pigment concentration difference occurs in the mixed ink, and this appears as a density difference in the recorded image. there is a possibility.

  In addition, since the ink cartridge described in Patent Document 2 stirs by circulating the ink in the ink cartridge by the circulation means, it is necessary to drive the circulation means before using the ink. Therefore, the recording operation cannot be performed while the circulating means is driven, and a recording waiting time is generated. Therefore, it has been demanded to shorten the stirring time.

  The present invention provides an ink jet recording apparatus capable of reducing a density difference generated in a recorded image between an early stage of use of an ink cartridge and a later stage of use, and shortening a recording waiting time by circulating stirring, and an ink cartridge used for the same. Objective.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, an ink includes a housing in which an ink storage chamber for storing ink is formed, and a communication portion that communicates the space located outside the housing with the ink storage chamber. In the cartridge, the communication portion includes a communication port formed on an outer surface of the housing, a merge channel having one end communicating with the communication port, one end communicating with the merge channel, and the other end of the communication channel. A branch channel that communicates with the ink storage chamber, the branch channel including at least one first branch channel that communicates with a lower layer region in the ink storage chamber, and an upper layer above the lower layer region in the gravity direction. And at least one second branch flow channel communicating with the region, and when supplying ink for flowing ink from the ink storage chamber to the outside, the first branch flow channel and the second branch flow channel The ink leaked from the When the ink flow rate in the first branch flow path is Q1, the ink flow rate in the second branch flow path is Q2, and the ink flow rate in the first branch flow path is The ratio (Q1 / Q2) to the ink flow rate in the second branch flow path is smaller when the ink is supplied than when the ink flows backward from the outside to the ink storage chamber. To do.

  According to a second aspect of the present invention, there is provided an ink jet recording apparatus that performs recording on a recording medium by supplying ink from an ink distribution unit to a recording head, and discharging the ink from the recording head. An ink cartridge for storing ink to be supplied to the recording head, an ink distribution part that enables ink to flow between the ink cartridge and the recording head, and a reverse flow of ink from the ink distribution part to the ink cartridge An ink backflow means for allowing the ink cartridge to include a housing in which an ink storage chamber for storing ink is formed, and a communication portion for communicating the ink circulation portion with the ink storage chamber, The communication portion includes a communication port formed on the outer surface of the housing, a merge channel that has one end communicating with the communication port, and one end that communicates with the merge channel. And a branch channel whose other end communicates with the ink storage chamber, wherein the branch channel is at least one first channel communicating with a lower layer region in the ink storage chamber, At least one second flow path communicating with the upper layer area that exists above the lower layer area in the direction of gravity, and the first branch flow path during ink supply for flowing ink from the ink storage chamber to the outside And the ink flowing out from the second branch channel is merged in the merge channel, the ink flow rate in the first branch channel is Q1, and the ink channel in the second branch channel is Q2. In addition, the ratio (Q1 / Q2) of the ink flow rate in the first branch flow path and the ink flow rate in the second branch flow path is larger when the ink is supplied from the outside. Characterized in that less than when the ink backflow to flow the ink into.

  According to the present invention, it is possible to reduce the density difference generated in the recorded image between the initial use stage and the late use stage of the ink cartridge, and it is possible to reduce the recording waiting time due to stirring.

1 is a diagram illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating an appearance of an ink cartridge according to an embodiment. It is a figure which shows the external appearance of the board | substrate with which the ink cartridge shown in FIG. 2 is equipped. FIG. 3 is an exploded perspective view of the ink cartridge shown in FIG. 2. FIG. 3 is a cross-sectional view illustrating an internal configuration of the ink cartridge. FIG. 3 is a cross-sectional view illustrating an internal configuration of the ink cartridge. FIG. 2 is an enlarged perspective view of a main part showing the recording head unit in FIG. 1 in detail. It is a perspective view which shows the structure of a cartridge mounting unit. It is a partial longitudinal cross-sectional view which shows typically the IX-IX line cross section of FIG. (A) is a partial longitudinal sectional view schematically showing a cross section taken along line Xa-Xa of FIG. 8, and (b) is a sectional view showing ink backflow means. It is a longitudinal cross-sectional view which shows typically the state which the flexible member shown in FIG.10 (b) reversed. It is a top view which shows the internal structure of the housing | casing of the cartridge mounting unit in 2nd Embodiment. It is an expansion perspective view of the E section shown in FIG.

  Hereinafter, embodiments of an ink cartridge and an inkjet recording apparatus according to the present invention will be specifically described with reference to the drawings. In addition, each following embodiment shows a suitable example for implementing this invention, and this invention is not limited to these structures.

[First Embodiment]
1. Inkjet Recording Device FIG. 1 is a diagram schematically showing the overall configuration of an inkjet recording device 100. An ink cartridge 1 as an ink storage container is detachably mounted on a recording apparatus main body (hereinafter also referred to as “apparatus main body”) 30 shown in FIG. The apparatus main body 30 includes a carriage 31, a recording head 32, a sub tank 51 (see FIGS. 8, 9, and 11), a conveying means (conveying means) 34, a control unit 35, an input / output unit 36, and the like. Although not particularly shown here, the recording apparatus main body 30 includes an exterior cover that can be opened and closed when attaching and detaching ink cartridges, a feeding cassette for loading recording media, and a conveying means from the feeding cassette. 34 is provided with a feeding means for feeding the recording medium to 34. Further, the recording apparatus main body 30 includes a discharge tray (not shown) that holds a recorded recording medium, an operation unit that performs various input operations, and the like. The recording device main body 30 is configured to be connectable to an external device (not shown) such as a computer, a digital camera, or a memory card via the input / output unit 36.

  The control unit 35 performs overall control of the recording apparatus main body 30, control of information communication with the ink cartridge 1, analysis of information input from an external device via the input / output unit 36, processing, and input / output unit 36. Execute information output. For example, the control unit 35 controls the operation of each drive unit such as the carriage 31, the recording head 32, the conveyance unit 34, the feeding unit, and a pump unit 300 as a decompression unit described later. In addition, the control unit 35 performs control to read out cartridge-specific information such as ink color, initial ink filling amount, and ink consumption amount from the storage element 5 (FIG. 3B) serving as storage means provided in the ink cartridge 1 and ink to the storage element 5. Control to write information such as consumption. Further, the control unit 35 analyzes and processes information such as a recording command and image data input from an external device via the input / output unit 36 and outputs information such as the remaining ink amount to the input / output unit 36. .

  A sub tank 51 serving as a mounting portion provided on the carriage 31 is detachably mounted with ink cartridges 1C, 1Bk, 1M, and 1Y that respectively store cyan (C), black (Bk), magenta (M), and yellow (Ye) inks. It is configured so that it can be installed. The ink cartridge 1Bk is wider and has a larger capacity than the other three ink cartridges 1C, 1M, and 1Ye. In addition, the recording head 32 includes ejection units for ejecting cyan (C), black (Bk), magenta (M), and yellow (Ye) inks, respectively, and each color ink supplied from the ink cartridge 1 is supplied. It is comprised so that it can discharge from each discharge port of each discharge part.

  When the user attaches / detaches or replaces the ink cartridge 1 to / from such a carriage 31, the user first opens an exterior cover (not shown) that covers the carriage 31, the conveying means 34, and the like. To do. When the open state of the outer cover is detected by the recording apparatus main body, the carriage 31 moves to a cartridge replacement position (not shown). The user can mount (see FIG. 7) or remove (see FIG. 8) the ink cartridge 1 from the head unit 38 mounted on the carriage 31 at the cartridge replacement position. The head unit 38 includes a cartridge mounting unit 50 (described later) and a recording head 32 (see FIG. 9).

  When the user closes the exterior cover after the ink cartridge 1 is attached or detached or exchanged, the closed state is detected by an exterior sensor (not shown). When the closed state is detected, the control unit 35 of the recording apparatus main body 30 reads out ink color information from the storage element 5 of the ink cartridge 1 mounted on the carriage 31. Based on the read ink color information, the control unit 35 determines whether or not the ink cartridges 1 of all colors (four colors in the present embodiment) are mounted on the carriage 31. When it is determined that there is an ink cartridge 1 of a color that is not mounted on the carriage 31, the control unit 35 displays an error message on the display panel of the operation unit or the display unit of the external device. Outputs a command to execute error display. On the other hand, when it is determined that all color ink cartridges are mounted on the carriage 31, the ink jet recording apparatus 100 is in a recordable state.

  When a recording command is input from the external device or the operation unit to the control unit 35, the control unit 35 determines whether or not the recording device is in a recordable state. When the recording is possible, the feeding means (not shown) picks up the recording media P loaded in the feeding cassette (not shown) one by one, and the picked-up recording media P is transferred to the transport means 34. Feed toward. The transport unit 34 includes a platen that supports the lower surface of the recording medium P, a transport roller that can transport the recording medium intermittently, a drive unit that rotationally drives the transport roller, and the like. The sent recording medium P is conveyed toward a discharge tray (not shown). In the intermittent conveyance operation of the recording medium P by the conveyance means 34, the carriage 31 intersects the conveyance direction of the recording medium P during the conveyance stop period between the conveyance operations (in the present embodiment, orthogonal). It moves on the recording medium P along the X-axis direction. When ink is ejected from the recording head 32 toward the recording medium P while the carriage 31 is moving, an image is formed on the recording medium. As described above, an image is formed on the recording medium by repeating the movement of the carriage, the ink ejection of the recording head, and the conveyance of the recording medium.

1-1. Head Unit Next, the configuration of the head unit 38 mounted on the carriage 31 of the inkjet recording apparatus 100 will be described in more detail.

  FIG. 9 is a partial longitudinal sectional view showing the configuration of the head unit 38 in the present embodiment. The head unit 38 has a recording head 32 having an ejection port 32a capable of ejecting ink, and a cartridge mounting in which the ink cartridge 1 is detachably mounted and the ink derived from the ink cartridge 1 can be supplied to the recording head 32. A unit 50. The cartridge mounting unit 50 is provided between the sub tank 51 and the holding unit 60 as a mounting unit that can mount the ink cartridge 1, a holding unit 60 that holds the sub tank 51 and the recording head 32. And a flexible member 70. The sub tank 51 is provided with an apparatus main body side interface section 50A to which a cartridge side interface section 1A (see FIG. 2) formed on the front surface 2c1 of the ink cartridge 1 described later is detachably connected.

  The apparatus main body side interface unit 50A includes an ink supply pipe 52, an opening pin 53, and a positioning pin 54, which are respectively inserted into the tube insertion port 8, the atmosphere communication hole 7, and the positioning hole 6 of the cartridge side interface unit 1A. It is possible to remove. Further, the sub tank 51 is formed with a joint chamber 56 for storing ink flowing in from the ink cartridge 1 through the ink supply pipe 52 and an ink chamber 57 communicating with the joint chamber 56. The joint chamber 56 is formed by the lower portion of the sub tank 51 and the holding portion 60, and the ink chamber 57 is formed by a gas-liquid impermeable flexible member 70 that is closely and fixed on the holding portion 60.

  The holding unit 60 also includes an ink channel 61 for supplying ink in the joint chamber 56 to the recording head 32, a decompression chamber 62 defined by the flexible member 70 and the ink chamber 57, and the decompression chamber 62 and the external space. And a decompression channel 63 that communicates with each other. The flexible member 70 has a flexible portion 70 a that is deformed by the pressure in the decompression chamber 62. When the pressure in the decompression chamber 62 is equal to or higher than a certain value, the flexible portion 70a protrudes upward as shown in FIGS. 9 and 10, and the pressure in the decompression chamber 62 is less than the certain value. In the case of a depressurized state, the state protrudes downward as shown in FIG. As shown in FIG. 10B, the opening formed at the end of the decompression flow path 63 is covered with a suction pad 320 in the decompression means so as to be openable. The subtank 51 and the holding unit 60 having the above configuration constitute an ink circulation unit that enables ink to flow between the ink cartridge 1 and the recording head 32.

  In the present embodiment, a structure in which the head unit 38 is detachably mounted on the carriage 31 is employed. However, the present invention is not limited to this. The present invention can also take a form in which the recording head 32 and the cartridge mounting unit 50 are detachably mounted on the carriage 31. Alternatively, the cartridge mounting unit 50 may be integrated with the carriage 31 and only the recording head 32 may be detachably mounted on the carriage 31. Further, the recording head 32 and the cartridge mounting unit 50 may be integrated with the carriage 31. In short, the carriage 31 may be configured so that the recording head 32 can be detachably or fixedly mounted, and the ink cartridge 1 can be detachably mounted.

2. Ink Cartridge Next, an example of an ink cartridge that can be used in the inkjet recording apparatus 100 shown in FIG. 1 will be described with reference to FIGS. 2 to 5A and 5B. The four ink cartridges 1C, 1Bk, 1M, and 1Ye used in this embodiment are the types of ink to be stored, the cartridge width (the width of 1Bk is wider than the width of 1C, 1M, and 1Ye), and the identification unit 9 The basic configuration is the same except that is different. Therefore, the configuration of the ink cartridge 1M will be described below as a representative.

  FIG. 2 is a perspective view showing the appearance of the ink cartridge 1M in the first embodiment of the present invention. 3A and 3B are views showing the appearance of the substrate 3 provided in the ink cartridge 1 of FIG. 2, wherein FIG. 3A is a front view and FIG. 3B is a side view. FIG. 4 is an exploded perspective view of the ink cartridge of FIG. 5A and 5B are cross-sectional views showing the internal configuration of the ink cartridge of FIG. 2, wherein FIG. 5A is a cross-sectional view taken along the line Va-Va of FIG. 2, and FIG. 5B is Vb-Vb of FIG. It is line sectional drawing. In the ink cartridge, the top, bottom, left and right, top surface, bottom surface, front surface, back surface, side surface, and the like are defined when the ink cartridge is mounted on the mounting portion, that is, depending on the orientation (posture) of the ink cartridge 1 in use.

2-1. Housing As shown in FIG. 2, the ink cartridge 1 as an ink storage container includes a rectangular parallelepiped housing 2 having an ink storage chamber 11. The housing 2 includes a first housing member 40 including an upper wall 2a, a bottom wall 2b, a front wall 2c, a back wall 2d, and a left wall 2e, and a second housing member 41 constituting the right wall 2f. It has a configuration. The second housing member 41 functions as a lid member that closes the opening formed by the upper wall 2a, front wall 2c, back wall 2d, and left wall 2e of the first housing member 40. The ink storage chamber 11 is a space constituted by the inner wall surface of the first housing member 40 and the flexible member 12 in close contact with the inner wall surface of the first housing member 40, and ink is contained in this space. Is stored. In the present embodiment, the flexible member 12 is configured by a sheet having flexibility and gas-liquid impermeability. Further, in the case 2, the outer surfaces of the upper wall 2a, the bottom wall 2b, the front wall 2c, the back wall 2d, the left wall 2e, and the right wall 2f are respectively an upper surface 2a1, a bottom surface 2b1, a front surface 2c1, and a rear surface 2d1. These are referred to as a left surface 2e1 and a right surface 2f1.

  In FIG. 2, the X-axis direction is the width direction of the ink cartridge 1 and is also the moving direction of the ink cartridge 1 mounted on the carriage 31 (the moving direction of the carriage 31). The Y-axis direction is the depth direction of the ink cartridge 1 and is also the cartridge attachment / detachment direction. The Z-axis direction is the vertical direction (gravity direction) of the ink cartridge, and is a direction orthogonal to the X-axis direction and the Y-axis direction. The θx direction is a rotation direction with the X axis as the rotation center axis, the θy direction is a rotation direction with the Y axis as the rotation center axis, and the θz direction is a rotation direction with the Z axis as the rotation center axis.

  In this embodiment, since the rectangular parallelepiped housing 2 is employed, the X-axis direction is orthogonal to the left surface 2e1 and the right surface 2f1, the Y-axis direction is orthogonal to the front surface 2c1 and the back surface 2d1, and the Z-axis direction is It is orthogonal to the upper surface 2a1 and the lower surface (bottom surface) 2b1.

  However, as will be described later, the shape of the housing 2 applicable in the present embodiment is not limited to a rectangular parallelepiped shape, and for example, all or a part of the surface constituting the housing 2 is configured by a curved surface or an inclined surface. It may be. When all or a part of the surfaces constituting the housing 2 are configured by curved surfaces or inclined surfaces, the X axis, the Y axis, and the Z axis are not necessarily orthogonal to these surfaces.

2-2. Cartridge-side interface unit As shown in FIGS. 2, 4, and 5, the front surface 2c1 of the housing 2 is provided with a cartridge-side interface unit 1A that is detachably connected to the apparatus body-side interface unit 50A. Yes. The cartridge-side interface unit 1A includes a substrate 3 provided with electrical contacts 4, a positioning hole 6 as a positioning unit, an atmospheric communication hole 7 as an atmospheric communication unit, a tube insertion port 8 as a communication port, an identification unit 9, and the like. It is a configuration that includes. The electrical contact 4, positioning hole 6, atmospheric communication hole 7, tube insertion port 8, and identification part 9 are respectively an electrical contact (electrical connection part) 55, positioning pin 54, and unsealing pin 53 in the apparatus main body side interface part 50 A. The ink supply pipe 52 and the identification member 65 are connected.

  Hereinafter, the configuration of the ink cartridge 1 will be described focusing on the cartridge-side interface unit 1A. As shown in FIGS. 2, 4, and 5, the tube insertion port 8 provided on the front surface 2 c 1 of the housing 2 has a predetermined distance below the upper wall 2 a of the housing 2 in the gravitational direction (vertical direction). It arrange | positions via the space | interval and is arrange | positioned in the vicinity of the bottom wall 2b in this embodiment. The tube insertion port 8 is formed by an opening portion of a seal member 19 inserted into one end portion of a communication path (communication portion) 22 formed in the lower portion of the housing 2. The seal member 19 is formed of a cylindrical elastic body (for example, rubber), and is inserted and fixed to one end portion of the communication flow path 22, and the aforementioned tube insertion port 8 is formed at one end portion thereof. An opening is formed.

  A slit 19a that can be opened and closed elastically is provided at the end of the seal member 19 on the back side (side closer to the ink storage chamber 11 than the tube insertion port 8), and the ink supply tube 52 is not inserted. Then, the slit 19a is in a closed state. When the slit 19a of the seal member 19 is in a closed state, the communication flow path 22 is in a blocked state, and the tube insertion port 8 and the ink storage chamber 11 are not in communication. Further, when the ink supply pipe 52 is inserted into the communication flow path 22, the slit 19 a of the seal member 19 is expanded by the ink supply pipe 52 to open, and communication between the ink supply pipe 52 and the ink storage chamber 11 is ensured. Is done. At this time, the inner peripheral surface of the seal member 19 is elastically in close contact with the outer peripheral surface of the ink supply pipe 52 so that ink does not leak out. By connecting the communication channel 22 and the ink supply pipe 52 in this manner, the ink in the ink storage chamber 11 can be supplied to the ink supply pipe 52.

  When the ink cartridge 1 is attached to the sub tank 51 of the head unit 38 mounted on the apparatus main body 30, the ink supply pipe 52 of the apparatus main body side interface unit 50 </ b> A is inserted into the pipe insertion port 8 of the ink cartridge 1. . For this reason, the ink cartridge 1 is restricted from moving in the direction (X-axis direction and Z-axis direction) along the front surface 2c1 of the housing 2. That is, the tube insertion port 8 also plays a role of suppressing a positional deviation in the surface direction of the front surface 2c1 of the ink cartridge 1. In addition, in this embodiment, although the pipe insertion opening always opened is employ | adopted as a connection part, a connection part is not limited to the structure always opened. That is, the connecting portion only needs to be configured so that the ink supply pipe 52 can be inserted, and does not need to be opened before the ink supply pipe 52 is inserted.

  FIG. 5A shows the state of the ink cartridge 1 before being attached to the sub tank 51, that is, the ink cartridge 1 in an unused state. In this unused state, the sealing film 18 as a sealing member is closely attached and fixed to the periphery of the tube insertion port 8 so as to seal the tube insertion port 8. For this reason, the sealing film 18 functions as an ink leakage prevention means for preventing ink leakage from the ink storage chamber 11 before using the cartridge during distribution or the like. When the ink cartridge 1 is mounted, the sealing film 18 is opened by the penetration of the ink supply pipe 52.

  The substrate 3 provided with the electrical contacts 4 is provided at a position (upper position) closer to the upper surface 2a1 than the tube insertion port 8 on the front surface 2c1 of the housing 2. As shown in FIG. 3, a plurality of (five in the figure) electrical contacts 4 are provided on the front surface of the substrate 3, and a storage element 5 is provided on the back surface of the substrate 3. The electrical contact 4 and the memory element 5 are connected by wiring through a through hole provided in the substrate.

  The storage element 5 is an IC chip including an information storage unit (memory unit) and a control circuit. In the information storage unit, unique information of the cartridge 1 is stored. Specific information of the cartridge 1 includes, for example, information on the color of ink stored in the ink storage chamber 11, information on the initial filling amount of ink, information on the consumption of ink supplied from the ink storage chamber to the outside, Information on the date of manufacture. The configuration of the information storage unit (memory unit) is not particularly limited, and various forms such as EEPROM and FeRAM are applicable. On the other hand, the control circuit can analyze the information sent from the control unit 35 of the recording apparatus main body 30, write the information in the information storage unit, read the information from the information storage unit, and output the information to the control unit 35. It is configured as possible. For example, the control circuit can analyze the ink consumption amount information and the ink color information sent from the control unit 35 and write the ink consumption amount information and the ink color information into the information storage unit. Further, the control circuit can read out ink color information and ink consumption information stored in the information storage unit, and can output the read information to the control unit 35.

  An electrical contact (electrical connection part) 4 on the cartridge side provided in the cartridge 1 can be electrically connected to an electrical contact (electrical connection part) 55 on the main body side. As shown in FIG. 4 is a contact position 4 a with the electrical contact 55. A plurality of electrical contacts 4 are provided on the surface of the substrate 3. The plurality of electrical contacts 4 include, for example, a contact from which a clock signal is input from the recording apparatus main body, a contact from which data such as ink consumption is input / output, and a contact from which power to operate the storage element is supplied from the recording apparatus main body. , Contacts connected to ground, etc. are included. FIG. 3A shows the case where the number of electrical contacts 4 is 5. However, the number of electrical contacts is not limited to 5, and can be increased or decreased as necessary.

  In this embodiment, the electrical contact 4 should just be arrange | positioned in the position which can oppose the electrical contact 55 along a cartridge mounting direction (Y-axis direction). Therefore, it is desirable to arrange the electrical contacts 4 on a surface that intersects the cartridge mounting direction (Y-axis direction) (for example, one surface of the substrate 3 that intersects the cartridge mounting direction). By connecting the electrical contact 4 on the cartridge side to the electrical contact 55 on the main body side, the storage element 5 of the ink cartridge 1 and the control unit 35 of the recording apparatus main body 30 are electrically connected. As a result, the control unit 35 can read information stored in the storage element 5 (for example, the cartridge-specific information). Similarly, the control unit 35 can write information (for example, information related to the amount of ink consumed by the recording operation) to the storage element 5.

2-3. Ink Storage Chamber Next, the internal configuration of the ink cartridge 1 will be described focusing on the configuration of the ink storage chamber 11. FIG. 4 is an exploded perspective view of the ink cartridge 1 of FIG. The ink storage chamber 11 includes an inner wall surface of the first housing member 40 of the housing 2 and a flexible member 12 (a flexible sheet) in close contact with the edge of the inner wall surface of the first housing member 40. And a chamber for storing ink in an internal space formed by the above.

  Inside the ink storage chamber 11, a negative pressure generating spring 13 as a negative pressure generating member for generating a negative pressure in the ink storage chamber 11 and a rectangular shape smaller than the inner wall surface of the first housing member 40 are formed. A plate-like member 14 is arranged. One end of the negative pressure generating spring 13 is engaged with the inner surface 2e2 of the left wall 2e of the first housing member 40, and the other end of the negative pressure generating spring 13 is engaged with the plate member 14. The negative pressure generation spring 13 biases the flexible member 12 through the plate-like member 14 in the direction in which the ink storage chamber expands, thereby maintaining the inside of the ink storage chamber 11 within a certain negative pressure range.

  When ink in the ink storage chamber 11 is reduced by ink supply from the ink cartridge 1 to the external space, that is, ink supply to the recording apparatus main body 30, if the volume in the ink storage chamber 11 is constant, the ink storage chamber 11 The negative pressure inside increases significantly. However, in this embodiment, when the ink in the ink storage chamber 11 decreases, the negative pressure generating spring 13 contracts accordingly, and the plate-like member 14 moves in a direction to reduce the internal volume of the ink storage chamber 11. A significant increase in negative pressure is suppressed, and a constant negative pressure can be maintained.

  The space between the ink storage chamber 11 and the second housing member 41 (non-ink storage space) is a porous filter 15 provided in the left wall 2e of the ink cartridge 1, the atmospheric communication passage 16, and the atmospheric communication hole. 7 (see FIG. 6A) communicates with the external space of the ink cartridge 1. Specifically, the right wall 2f of the ink cartridge 1 is provided with an air communication path 16 formed of a meandering groove, one end of the groove communicates with the non-ink storage space, and the other end communicates with the air communication hole 7. Communicating with A label 25 is affixed to the outer surface of the left wall 2e so as to cover the serpentine groove, and the groove covered with the label 25 communicates with the non-ink storage space S1 (see FIG. 5B). It functions as an air communication path that communicates with the hole 7. Therefore, when the plate-like member 14 moves in the direction of reducing the internal volume of the ink storage chamber 11, the space between the ink storage chamber 11 and the second housing member 41 (non-ink storage space) is opened to the atmosphere. The atmosphere is taken in through the atmosphere communication passage 16 from 26.

2-4. Ink supply and ink supply flow path In the ink cartridge 1 mounted in the sub tank 51 of the apparatus main body 30, when the ink in the ink storage chamber 11 is consumed by the ink discharge operation of the recording head 32, the plate-like member 14 is negative. It moves against the pressure generating spring 13. When the consumption of ink proceeds and the negative pressure in the ink storage chamber 11 further increases due to the movement of the plate-like member 14, and the negative pressure reaches the meniscus force of the porous filter 15, the porous filter 15 is removed from the atmospheric communication passage 16. Passing through, air is introduced into the ink storage chamber 11. Thereafter, since the atmosphere is introduced into the ink storage chamber 11 from the atmosphere communication path 16 by the amount of ink supplied, the negative pressure in the ink storage chamber 11 is maintained within a certain range, and the negative pressure is more than necessary. There is no increase. As described above, in the present embodiment, since the atmosphere enters the ink storage chamber 11 from the middle of the ink supply operation, most of the ink stored in the ink storage chamber 11 can be used up. It becomes.

  Here, the configuration of the communication flow path 22 as a communication portion for communicating the ink cartridge 1 of the present embodiment and the external space will be described with reference to FIGS. 6A and 6B. 6A is a view showing a state where the ink supply tube 52 is inserted into the tube insertion port (communication port) 8 of the ink cartridge 1, and FIG. 6B is a view shown in FIG. 6A. It is an enlarged view (b section enlarged view of Drawing 6 (a)) which expands and shows the neighborhood of pipe insertion slot 8.

  In the present embodiment, the communication channel 22 includes a merging channel 200 that communicates with a tube insertion port (communication port) 8 formed in the front surface 2 c 1 of the housing 2, and one end portion that communicates with the merging channel 200. A branch channel having an end communicating with the ink storage chamber 11 is provided. In the present embodiment, two branch channels, a first branch channel 210 and a second branch channel 220, are provided as the branch channels. In addition, the opening 221 that connects the second branch flow path 220 and the ink storage chamber 11 has a greater gravity direction than the opening 211 that connects the other end of the first branch flow path 210 and the ink storage chamber 11. It is located upward in the (vertical direction). Further, the second branch flow path 220 communicates with the merge flow path 200 at the opening 222, and the first branch flow path 210 communicates with the merge flow path 200 at the opening 212. The communication channel 22 in the present embodiment is formed by sealing one surface of the substantially groove-shaped opening formed integrally with the first housing member 40 with a flexible member. Is not limited to this embodiment.

  In the present embodiment, both the first branch flow path 210 and the second branch flow path 220 have the same cross-sectional shape and cross-sectional area as the merge flow path 200. In addition, the angle α formed between the central axis of the first branch flow path 210 and the central axis of the merging flow path 200 is the angle β formed between the central axis of the second branch flow path 220 and the central axis of the merging flow path 200. It is set to be larger. In the present embodiment, the angle α is set to about 180 degrees, and the angle β is set to about 90 degrees. However, the angles α and β are not limited to the present embodiment, and the angles α and β can be set within a range of ± 90 degrees and α> β. The angle α is preferably 170 degrees or more and 190 degrees or less, and particularly preferably 180 degrees. Further, the angle β is preferably 80 degrees or more and 100 degrees or less, and particularly preferably 90 degrees.

  When the ink cartridge 1 having the above configuration is attached to the sub tank 51 of the apparatus main body 30, the ink stored in the ink cartridge 1 is transferred from the first and second branch flow paths 210 and 220 to the merge flow path 200. leak. The ink flowing into the merge channel 200 flows out from the tube insertion port 8 to the ink supply tube 52 inserted into the seal member 19, then flows into the joint chamber 56 of the sub tank 51, and is supplied to the recording head 32. .

  By the way, when the ink cartridge 1 is left for a long time in the state of being attached to the sub tank 51, or when the ink cartridge 1 is left for a long time in the same posture before being attached to the sub tank 51, the ink storage chamber 11 is stored. The ink coloring material gradually settles. In the present embodiment, since pigment is used as a color material used for ink, pigment particles settle in the ink storage chamber 11. Therefore, in the present embodiment, the ink in the ink storage chamber 11 has a concentration gradient of pigment particles from the lower part to the upper part. That is, in the lower layer region near the bottom surface 11a of the ink storage chamber 11, an ink layer having a high pigment concentration (coloring material concentration) and an excessively dark color is formed, and the upper layer positioned above the lower layer region in the gravity direction. In the region, a low density ink layer having a low pigment density and an excessively light color is formed.

  In the present embodiment, since the first branch flow path 210 communicates with the ink storage chamber 11 through the opening 211 located in the vicinity of the bottom surface 11a of the ink storage chamber 11, the first branch flow path 210 is a pigment. It communicates with the lower layer area where high density ink with high density exists. Further, since the second branch flow path 220 communicates with the ink storage chamber 11 through the opening 221 at a position higher than the opening 211, the second branch flow path 220 has a low concentration ink with a lower pigment concentration. It communicates with the upper layer area where there is. Therefore, low concentration ink flows from the second branch flow path 220 and high concentration ink flows from the first branch flow path 210 to the merge flow path 200. The ratio of the flow rate of ink flowing from the first branch flow channel 210 to the merge flow channel 200 and the flow rate of ink flowing from the second branch flow channel 220 to the merge flow channel 200 is the first flow rate. The value corresponds to the ratio between the flow resistance of the branch flow path 210 and the flow resistance of the second branch flow path 220. Thereafter, the ink that has passed through the merging channel 200 flows into the joint chamber 56 of the sub tank 51 through the ink supply pipe 52, and is supplied to the recording head 32 through the ink channel 61.

  As described above, in this embodiment, the low concentration ink and the high concentration ink in the ink storage chamber 11 flow into the merging flow path 200 at a certain flow rate ratio, and thereafter are supplied to the recording head 32. Mixed in. Therefore, even when the ink cartridge 1 is left in a constant posture for a long period of time, it is possible to stably supply ink having a constant pigment concentration during use.

2-5. Next, the agitation operation of the ink in the ink cartridge 1 executed by the ink jet recording apparatus 100 according to this embodiment in which the ink cartridge 1 is mounted will be described. As described above, when the ink cartridge 1 is left in the same posture for a long period of time, the ink coloring material (pigment particles in the case of pigment ink) settles and a density gradient of the coloring material occurs in the ink. At this time, if the settled color material is easy to flow, as described above, the ink taken out from the first and second branch flow paths 210 and 220 is merged so that the ink having a stable density can be obtained. 32 can be supplied. However, if the ink cartridge 1 is left in the same posture for a long time, the color material may accumulate on the bottom surface 11a of the ink storage chamber 11 and the density may affect the print quality.

  Therefore, in the present embodiment, when the ink cartridge 1 mounted in the sub tank 51 is left for a long period of time or the like is in a predetermined use condition, the ink is caused to flow backward from the apparatus main body 30 into the ink storage chamber 11 to store the ink. A reverse flow stirring operation is performed to stir the ink in the chamber 11. Hereinafter, this backflow stirring operation will be described with reference to FIGS. 1, 6, 9 to 11.

  The backflow stirring operation executed in the present embodiment uses a decompression means that changes the pressure of the decompression chamber 62 formed in the cartridge mounting unit 50 to deform and invert the flexible portion 70a of the flexible member 70. As shown in FIG. 10 (b), this decompression means includes a suction pad 320 provided on the side surface of the feeding device 330, a tube 310 connected to the suction pad 320, and a pump unit 300 connected to the tube 310. With.

  Here, the backflow agitating operation in the present embodiment, which is performed using the pressure reducing means, will be described in detail. FIG. 9 is a longitudinal sectional view (sectional view taken along line IX-IX in FIG. 8) showing a state (initial state) of the flexible member 70 before and after the start of the backflow stirring operation. 10 (a) is a partially longitudinal front view of FIG. 8 (cross-sectional view taken along line Xa-Xa of FIG. 8), FIG. 10 (b) is a partially enlarged view of FIG. 9, and FIG. It is a longitudinal cross-sectional view which shows the state (inversion state) of the member 70. FIG.

  When performing the backflow stirring operation, first, the head unit 38 is moved together with the carriage 31 in the main scanning direction (X-axis direction), and the suction pad 320 is disposed around the decompression port 64 as shown in FIG. Abut. Thereby, the periphery of the decompression port 64 and the suction pad 320 are in contact with each other in an airtight state, and the pump unit 300 and the decompression flow path 63 are connected via the suction pad 320 and the tube 310. After the connection, the decompression chamber 62 is decompressed by the pump unit 300, whereby the flexible portion 70a of the flexible member 70 is pulled toward the decompression chamber 62, and the flexible portion 70a is inverted downward. As a result, a sudden volume change of the decompression chamber 62 occurs, and a volume of ink corresponding to the changed volume is introduced from the ink cartridge 1 into the joint chamber 56. Thereafter, when the pump unit 300 is opened to the atmosphere, the flexible portion 70a that is inverted downward returns to the initial state (a state protruding upward) by the elastic restoring force of the flexible member 70. As a result, a sudden volume change (decrease) occurs in the ink chamber 57 and the joint chamber 56, and a volume of ink corresponding to the changed volume is returned to the ink cartridge 1 via the ink supply pipe 52.

  FIG. 6B shows a state in which the ink returned to the ink cartridge 1 flows into the ink storage chamber 11 during the backflow stirring operation. As shown in FIG. 6B, the ink flowing backward from the ink supply pipe 52 passes through the merged flow path 200 and then flows into the first branch flow path 210 through the opening 212, while the opening. It flows also into the 2nd branch flow path 220 through 222. As described above, in the present embodiment, the angle formed by the central axis of the first branch flow path 210 and the central axis of the merge flow path 200 is set to about 180 degrees, and the merge flow path 200 and the first branch flow path are formed. The flow path composed of the flow path 210 constitutes a continuous and substantially straight flow path. For this reason, the flow resistance when ink flows from the merging flow path 200 to the first branch flow path 210 is relatively small, and the ink smoothly passes through the first branch flow path and passes through the ink storage chamber. It flows into the lower layer area.

  On the other hand, the angle formed by the central axis of the merging channel 200 and the central axis of the second branch channel 220 is set to about 90 degrees as described above. That is, the flow path composed of the merge flow path 200 and the second branch flow path 220 is a bent flow path. For this reason, the ink that has passed through the merging channel 200 easily flows to the first branch channel 210 that is arranged on the same straight line as the merging channel 200, but is arranged in a direction perpendicular to the merging channel 200. It is difficult to flow to the second branch flow path 220. Therefore, the ratio (Q1 / Q2) between the ink flow rate (Q1) in the branch flow path 210 and the ink flow rate (Q2) in the second branch flow path 220 is different between the ink supply time and the ink reverse flow time. Become. That is, since the ratio (Q1 / Q2) at the time of ink supply is configured to be smaller than the ratio (Q1 / Q2) at the time of ink backflow, the pigment particles existing in the lower layer region, etc. The color material can be effectively stirred. Thereby, the backflow stirring operation can be completed in a short time, and the standby time for the recording operation can be shortened. The ink flow rates indicated by Q1 and Q2 are both flow rates per the same time (unit time). In the present embodiment, a large amount of pigment particles in the dense ink layer can be wound up by a single backflow agitating operation, and the pigment concentration of the ink existing in the lower layer region can be lowered, thereby minimizing the recording waiting time. be able to.

  Next, the necessity of the backflow stirring operation and the method for determining the number of stirring operations will be described.

  The necessity of the backflow stirring operation and the number of stirring operations are determined by the control unit 35 based on information stored in the storage element 5 of the ink cartridge 1. The information stored in the storage element 5 includes the date of manufacture of the ink cartridge, the type of ink, the date of the previous backflow stirring operation, the amount of ink injected into the ink storage chamber, and the remaining amount of ink. The necessity of the backflow stirring operation and the number of stirring operations are determined from one or more pieces of information. For example, it is necessary based on the elapsed time from the date of manufacture when the new ink cartridge 1 is installed in the sub tank 51, the type of ink, the amount of ink injected into the ink storage chamber 11, the ink injection time (for example, date), etc. Determine the number of backflow stirring operations. The longer the elapsed time from the date of manufacture, the greater the amount of ink injected into the ink storage chamber 11, and the more readily the color material settles, the greater the number of backflow agitation operations. However, the storage environment such as the storage posture and temperature / humidity of the unused ink cartridge 1 is unknown. Therefore, when the combination of the ink type and the ink flow rate of the unused ink cartridge 1 is a combination that causes a steep density gradient in the ink, the number of times that the ink can be sufficiently stirred regardless of the elapsed time is set. It is desirable to set.

  In addition, when the ink cartridge 1 is in use, the number of stirring operations is determined from the elapsed time from the previous backflow stirring, the type of ink, and the remaining amount of ink. The longer the elapsed time, the greater the amount of ink remaining, and the more likely the ink to settle, the more stirring operations are performed.

  In this way, by determining the conditions regarding the implementation of the backflow stirring operation based on the information stored in the storage element 5, the minimum necessary stirring operation can be set, and the waiting time due to the stirring operation until recording can be shortened. Is possible.

  Further, in this embodiment, as shown in FIG. 10A, four decompression chambers 62 provided corresponding to each of the four ink cartridges 1 are gathered in one decompression flow path 63, and four decompression chambers are collected. The chamber 62 is decompressed simultaneously. That is, one decompression port 64 communicating with one decompression flow path 63 is provided on the side wall of the cartridge mounting unit 50, and the four decompression chambers 62 are decompressed simultaneously using one decompression means including one suction pad 320. It is like that. This makes it possible to simplify the pressure reducing means and reduce the cost. Further, in the configuration in which a plurality of (four) ink cartridges 1 are back-stirred in the same process as in the present embodiment, in order to keep the ink in all the ink cartridges in a good state, the most stirring operation It is desirable to perform the stirring operation in accordance with the ink cartridge that requires the ink.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the first branch flow channel 210 communicating with the lower layer region of the ink storage chamber 11 and the second branch flow channel 220 communicating with the upper layer region of the ink storage chamber 11 are as follows. It is composed. Other configurations are the same as those in the first embodiment, and the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals in FIG.

FIG. 12 is a perspective view showing the internal structure of the first housing member 40 of the housing 2 in the second embodiment, and FIG. 13 is an enlarged perspective view of a portion E in FIG. A merge channel 200, a first branch channel 210, a second branch channel 220, and the like are shown.
In the second embodiment, a branch port 405 is formed at the end of the merged flow channel 200 communicating with the first and second branch flow channels 210 and 220, and the branch port 405 has the first branch flow. It branches into a lower outlet 407 communicating with the path 210 and an upper outlet 406. The lower outlet 407 is formed in a slit shape, and the width in the direction (X-axis direction) orthogonal to the gravity direction (vertical direction) is wider than the width in the gravity direction (Z-axis direction). Since the ink chamber has a width in the X-axis direction, the color material (pigment particles) of the settled ink is distributed over the entire width direction of the bottom surface 11 a of the ink storage chamber 11. Accordingly, when the predetermined flow path cross-sectional area is determined, the width of the bottom surface 11a of the ink storage chamber 11 is increased by increasing the width of the lower outlet 407 in the X-axis direction of the ink storage chamber 11 as in the present embodiment. Ink can flow widely in the direction. For this reason, the ink collected on the bottom surface 11a of the ink storage chamber 11 can be efficiently stirred. In addition, it is desirable that the width of the upper outlet 406 and the branch outlet 405 in the X-axis direction is also set to be equal to that of the lower outlet 407.

[Other Embodiments]
In each of the above embodiments, a plurality of (four) ink cartridges are configured to simultaneously depressurize by one depressurizing means, but the present invention is not limited to this. For example, a plurality of independent decompression means may be provided corresponding to each of the plurality of ink cartridges, and the backflow stirring operation may be performed independently for each ink cartridge.

  Furthermore, a plurality of ink cartridges may be divided into a plurality of groups, and the backflow stirring operation may be performed separately for each group. In this case, a plurality of pressure reducing means may be prepared corresponding to each of the plurality of groups, or communication between the single pressure reducing means and each group may be switched using a switching means such as a valve.

  In each of the above embodiments, the merging flow path is such that the ratio of the ink flow rate in the first branch flow path and the ink flow rate in the second branch flow path is smaller during ink backflow than during ink supply. The arrangement (angle) of each branch channel with respect to is set. However, the present invention is not limited to this, and the same function can be achieved by other configurations. For example, a one-way valve that can be opened and closed is provided between the second branch flow path and the merge flow path, the valve is opened when ink is supplied, and ink can be supplied to the merge flow path. It is configured to close and block part or all of the ink flowing out from the merging channel to the second branch channel. According to this, the ratio (Q1 / Q2) between the ink flow rate (Q1) of the first branch flow path and the ink flow rate (Q2) of the second branch flow path is greater when the ink is supplied and during the reverse flow stirring operation. It can be made smaller. In particular, if all the inflow of the ink into the second branch flow path is blocked by the valve during the backflow stirring operation, all of the ink from the merge flow path flows into the first branch flow path. The stirring operation for the lower layer region of the cartridge can be performed more strongly.

  Further, in each of the above embodiments, the case where one each of the first branch channel and the second branch channel is provided for the merge channel of each ink cartridge has been described. Either one or both of the path and the second branch channel may be configured by a plurality of channels.

DESCRIPTION OF SYMBOLS 1 Ink cartridge 2 Housing | casing 5 Memory | storage means 8 Pipe insertion port 11 Ink storage chamber 22 Communication path 51 Sub tank 60 Holding part 64 Pressure-reduction port 100 Inkjet recording apparatus 200 Merge flow path 210 1st branch flow path 220 2nd branch flow path 300 Pump unit 310 Tube 320 Suction pad 340 Decompression means P Recording medium α Angle formed by the central axis of the merged flow path and the central axis of the first branch flow path β The central axis of the merged flow path and the second branch flow path Angle made with the central axis

Claims (15)

A housing in which an ink storage chamber for storing ink is formed;
A communication portion that communicates a space located outside the housing with the ink storage chamber, the communication portion having a communication port formed on an outer surface of the housing, and one end communicating with the communication port. And a branch channel having one end communicating with the merge channel and the other end communicating with the ink storage chamber, wherein the branch channel communicates with at least a lower layer region in the ink storage chamber. One first branch channel;
And at least one second branch flow channel communicating with the upper layer region above the lower layer region in the direction of gravity,
At the time of supplying ink that causes ink to flow from the ink storage chamber to the outside, the ink that has flowed out of the first branch channel and the second branch channel is merged in the merge channel,
When the ink flow rate in the first branch flow path is Q1, and the ink flow rate in the second branch flow path is Q2,
The ratio (Q1 / Q2) between the ink flow rate in the first branch flow path and the ink flow rate in the second branch flow path is such that ink is supplied from the outside to the ink storage chamber when the ink is supplied. An ink cartridge characterized by being smaller than that when ink flows backward.   The ink cartridge according to claim 1, wherein ink having a higher color material concentration than the upper layer region is present in the lower layer region of the ink storage chamber due to sedimentation of the color material in the ink.   When the ink is supplied, the high-concentration ink that flows out from the lower layer region to the first branch flow path and the low-concentration ink that flows out from the upper layer region to the second branch flow path are combined. The ink cartridge according to claim 1, wherein the ink cartridge is supplied to the outside of the housing from the communication port after flowing into the path.   The angle formed between the central axis of the merging channel and the central axis of the first branch channel is larger than the angle formed between the central axis of the merging channel and the central axis of the second branch channel. The ink cartridge according to any one of 1 to 3.   5. The ink cartridge according to claim 4, wherein an angle formed by a central axis of the merging channel and a central axis of the first branch channel is 170 degrees or more and 190 degrees or less.   6. The ink cartridge according to claim 5, wherein an angle formed between a central axis of the merging channel and a central axis of the second branch channel is 80 degrees or more and 100 degrees or less.   The ink cartridge according to any one of claims 1 to 6, wherein the casing includes a decompression port connectable to a decompression unit that decompresses the ink storage chamber.   The ink cartridge according to any one of claims 1 to 7, wherein the communication port is connectable to an ink circulation portion for supplying ink to a recording head capable of ejecting ink.   The ink cartridge according to any one of claims 1 to 8, wherein the flow path communicating with the lower layer region is formed so that a width in a direction orthogonal to the gravity direction is wider than a width in the gravity direction. An ink jet recording apparatus that records ink on a recording medium by supplying ink from an ink distribution unit to a recording head and discharging the ink from the recording head,
The ink distribution part
An ink cartridge for storing ink to be supplied to the recording head;
An ink distribution section that enables distribution of ink between the ink cartridge and the recording head;
Ink backflow means for backflowing ink from the ink circulation section to the ink cartridge,
The ink cartridge is
A housing in which an ink storage chamber for storing ink is formed;
A communication part for communicating the ink circulation part and the ink storage chamber,
The communication section includes a communication port formed on the outer surface of the housing, a merge channel that has one end communicating with the communication port, one end that communicates with the merge channel, and the other that communicates with the ink storage chamber. The branch flow path includes at least one first branch flow path that communicates with a lower layer region in the ink storage chamber, and an upper layer that exists above the lower layer region in the gravity direction in the ink storage chamber. And at least one second branch channel communicating with the region,
At the time of supplying ink that causes the ink to flow from the ink storage chamber to the outside, the ink that has flowed out of the first branch channel and the second branch channel is merged in the merge channel,
When the ink flow rate in the first branch channel is Q1, and the ink channel in the second branch channel is Q2,
The ratio (Q1 / Q2) between the ink flow rate in the first branch flow path and the ink flow rate in the second branch flow path is such that ink is supplied from the outside to the ink storage chamber when the ink is supplied. An ink jet recording apparatus characterized in that the ink jet recording apparatus is smaller than that at the time of back flow of ink.   The ink jet recording apparatus according to claim 10, wherein the ink backflow unit causes the ink to flow back from the ink circulation unit to the ink storage chamber by increasing the pressure of the ink circulation unit to be higher than the pressure of the ink storage chamber.   The ink jet recording apparatus according to claim 10, wherein the ink cartridge includes a storage unit that stores information for determining an operation of the ink backflow unit.   The ink backflow unit is configured to perform ink backflow based on at least one of information on ink injection time, ink type, date of previous ink backflow, ink injection amount, and ink remaining amount stored in the storage unit. The ink jet recording apparatus according to claim 12, wherein the operation of the means is determined. The ink circulation unit includes a plurality of the ink cartridges,
The inkjet recording according to any one of claims 10 to 13, wherein the backflow unit performs a backflow of ink from the ink circulation unit to the ink storage chamber in the same process with respect to all of the plurality of ink cartridges. apparatus.   The ink backflow means performs the backflow of the ink to all of the plurality of ink cartridges when there is at least one ink cartridge that requires the backflow of ink among the plurality of ink cartridges. Item 15. The ink jet recording apparatus according to Item 14.