Liquid supply device, inkjet recording apparatus including the same, and liquid supply method

Description

Technical Field

[0001] The present disclosure relates to a liquid supply device and an inkjet recording apparatus including the same.

Background Art

[0002] Patent Document 1 discloses an inkjet printer having a cartridge that stores ink supplied to a recording head, a pressure damper disposed between the cartridge and the recording head and having a storage chamber formed therein, and a pump. The pump sucks ink adhering to the nozzles of the recording head. The printer further has a gas supply means for supplying air to the storage chamber. In this technology, even if the gas in the storage chamber flows out of the pressure damper, the gas supply means can supply gas to the storage chamber, so that the damper function of the pressure damper can be maintained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] A liquid supply device according to one aspect of the present disclosure includes at least one pump having a suction port for receiving a liquid, a chamber for receiving the received liquid together with a gas reservoir, and a discharge port for discharging the liquid received in the chamber, and an air supply mechanism capable of supplying gas to the chamber.

[0005] An inkjet recording apparatus according to another aspect of the present disclosure includes an ink head that receives supply of ink and discharges the ink onto a recording medium, and the liquid supply device described above that supplies the ink as the liquid to the ink head.

Brief Description of the Drawings

[0006]

Figure 1

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[0007] Hereinafter, a recording apparatus according to an embodiment of the present disclosure will be described with reference to the drawings. In the following embodiments, as a specific example of the recording apparatus, an inkjet printer equipped with an ink head for discharging ink for image formation onto a wide and long recording medium will be exemplified. The inkjet printer is suitable for digital textile printing in which images such as characters and patterns are printed on a recording medium made of a fabric such as a woven or knitted fabric by an inkjet method. Of course, the recording apparatus according to the present disclosure can also be used for applications such as printing various images on a recording medium such as a paper sheet or a resin sheet.

[0008] [Overall Configuration of Inkjet Printer] FIG. 1 is a perspective view showing the overall configuration of an inkjet printer 1 according to the first embodiment of the present disclosure, and FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. 1. The inkjet printer 1 is a printer that prints an image on a wide and long workpiece W (recording medium) by an inkjet method. As an example, the width of the workpiece W extends several meters. The printer 1 includes a device frame 10, a workpiece conveyance unit 20 incorporated in the device frame 10, and a carriage 3. In the present embodiment, the left-right direction is the main scanning direction S (FIG. 3) during printing on the workpiece W, and the direction from the rear to the front is the sub-scanning direction (the conveyance direction F of the workpiece W, which is a direction intersecting the main scanning direction S).

[0009] The device frame 10 forms a framework for mounting various components of the inkjet printer 1. The workpiece conveyance unit 20 is a mechanism that intermittently feeds (conveys) the workpiece W so that the workpiece W advances in the conveyance direction F from the rear to the front in the printing area where the inkjet printing process is performed. The carriage 3 mounts an ink head 4, a pretreatment liquid head 5, a post-treatment liquid head 6, and a sub-tank 7, and reciprocates in the main scanning direction S (left-right direction) intersecting the conveyance direction F of the workpiece W during the inkjet printing process.

[0010] The device frame 10 includes a central frame 111, a right frame 112, and a left frame 113. The central frame 111 forms a framework for mounting various components of the inkjet printer 1 and has a left-right width corresponding to the workpiece conveyance unit 20. The right frame 112 and the left frame 113 are erected adjacent to the right and left of the central frame 111, respectively. The area between the right frame 112 and the left frame 113 is a printing area 12 where printing processing is executed on the workpiece W.

[0011] The right frame 112 forms a maintenance area 13. The maintenance area 13 is an area for retracting the carriage 3 when the printing process is not executed. In the maintenance area 13, cleaning processes, purge processes, etc. of the nozzles (discharge holes) of the ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 are performed, and caps are also fitted. The left frame 113 forms a turning area 14 of the carriage 3. The turning area 14 is an area where the carriage 3 that has main-scanned the printing area 12 from right to left in the printing process temporarily enters when performing the main scanning in the reverse direction.

[0012] Above the device frame 10, a carriage guide 15 for causing the carriage 3 to reciprocate in the left-right direction is assembled. The carriage guide 15 is a flat plate-shaped member that is long in the left-right direction and is disposed above the work conveyance unit 20. A timing belt 16 is assembled to the carriage guide 15 so as to be capable of circular movement in the left-right direction (main scanning direction). The timing belt 16 is an endless belt and is driven to circularly move in the left direction or the right direction.

[0013] The carriage guide 15 is equipped with a pair of upper and lower guide rails 17 that hold the carriage 3 in a state where it can reciprocate in the main scanning direction S so as to extend in parallel in the left-right direction. The carriage 3 is engaged with the guide rails 17. Also, the carriage 3 is fixed to the timing belt 16. The carriage 3 moves in the left direction or the right direction along the carriage guide 15 while being guided by the guide rails 17 as the timing belt 16 circularly moves in the left direction or the right direction.

[0014] Referring mainly to FIG. 2, the work conveyance unit 20 includes a feed roller 21 that feeds out the work W before printing and a take-up roller 22 that takes up the work W after printing. The feed roller 21 is disposed at the lower rear of the apparatus frame 10 and is the take-up shaft of the feed roll WA, which is a wound body of the work W before printing. The take-up roller 22 is disposed at the lower front of the apparatus frame 10 and is the take-up shaft of the take-up roll WB, which is a wound body of the work W after the printing process. The take-up roller 22 is attached with a first motor M1 that rotationally drives the take-up roller 22 about its axis to perform the take-up operation of the work W.

[0015] The path between the feed roller 21 and the take-up roller 22 and passing through the printing area 12 serves as the conveyance path of the work W. In this conveyance path, a first tension roller 23, a work guide 24, a conveyance roller 25, a pinch roller 26, a folding roller 27, and a second tension roller 28 are arranged in order from the upstream side. The first tension roller 23 applies a predetermined tension to the work W on the upstream side of the conveyance roller 25. The work guide 24 changes the conveyance direction of the work W from upward to forward and conveys the work W into the printing area 12.

[0016] The conveyance roller 25 is a roller that generates a conveyance force for intermittently feeding the work W in the printing area 12. The conveyance roller 25 is rotationally driven about its axis by a second motor M2, and intermittently conveys the work W in the forward direction (predetermined conveyance direction F) so that the work W passes through the printing area 12 (image forming position) facing the carriage 3. The pinch roller 26 is arranged to face the conveyance roller 25 from above and forms a conveyance nip portion with the conveyance roller 25.

[0017] The folding roller 27 changes the conveyance direction of the workpiece W that has passed through the printing area 12 from the forward direction to the downward direction, and guides the workpiece W after the printing process to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W on the downstream side of the conveyance roller 25. A platen 29 is disposed below the conveyance path of the workpiece W in the printing area 12.

[0018] The carriage 3 reciprocates in the main scanning direction S (the left-right direction in this embodiment) that intersects (orthogonal in this embodiment) the conveyance direction F while being cantilever-supported by the guide rail 17. The carriage 3 includes a carriage frame 30, an ink head 4, a pretreatment liquid head 5, a post-treatment liquid head 6, and a sub-tank 7 (FIG. 3) mounted on the carriage frame 30. The carriage frame 30 includes a head support frame 31 and a back frame 32.

[0019] The head support frame 31 is a horizontal plate that holds the above-mentioned heads 4 to 6. The back frame 32 is a vertical plate that extends upward from the rear edge of the head support frame 31. As described above, the timing belt 16 is fixed to the back frame 32. Also, the guide rail 17 is engaged with the back frame 32. That is, in this embodiment, the back frame 32 is an engaging portion that is held by the guide rail 17 in a cantilever state. The head support frame 31 is a horizontal plate whose rear end side is cantilever-supported by the guide rail 17 by the engaging portion.

[0020] Note that the cantilever state means that, in the carriage 3, the engaging portion (the back frame 32), which is the portion held by the guide rail 17 as the holding member, exists only on one side, upstream or downstream, from the center of the carriage 3 in the conveyance direction F, and there is no other engaging portion on the opposite side of the side where the engaging portion exists. The engaging portion may be further disposed outside the range where the ink head 4 and the processing head are disposed in the conveyance direction F. That is, the engaging portion may be disposed only on the upstream side or only on the downstream side with respect to the range where the ink head 4 and the processing head are disposed in the conveyance direction F.

[0021] [Details of the carriage] Further explanation will be given for the carriage 3. FIG. 3 is an enlarged perspective view of the carriage 3 shown in FIG. 1. In FIG. 3, the conveyance direction F (sub-scanning direction) of the work W and the main scanning direction S which is the moving direction of the carriage 3 are shown. In FIG. 3, a plurality of ink heads 4 for discharging ink for image formation onto the work W, a pretreatment liquid head 5 and a post-treatment liquid head 6 for discharging a non-coloring treatment liquid, and a plurality of sub-tanks 7 for supplying the ink and the treatment liquid to these heads 4 to 6 are shown as an example mounted on the carriage 3.

[0022] Each of the ink heads 4 includes a number of nozzles (ink discharge holes) for discharging ink droplets by a discharge method such as a piezo method using a piezo element or a thermal method using a heating element, and an ink passage for guiding ink to this nozzle. As the ink, for example, an aqueous pigment ink containing an aqueous solvent, a pigment, and a binder resin can be used. The plurality of ink heads 4 in the present embodiment can discharge 8 colors of ink. The ink heads 4 are mounted on the head support frame 31 of the carriage 3 so as to be arranged in two rows in the main scanning direction S. Each color ink head 4 has two heads respectively.

[0023] Specifically, the ink head 4 has a first upstream ink head 41A and a first downstream ink head 41B. These ink heads 4 discharge yellow ink. Further, the ink head 4 has a second upstream ink head 42A and a second downstream ink head 42B. These ink heads 4 discharge magenta ink. Similarly, as shown in FIG. 3, two ink heads 4 discharging the same color ink are arranged at positions shifted from each other in the conveyance direction F and the main scanning direction S. Taking these two ink heads 4 as a set, a total of 8 sets of ink heads 4 (41A to 48A, 41B to 48B) discharge inks of different colors from each other.

[0024] The pretreatment liquid head 5 and the post-treatment liquid head 6 are arranged at positions different from those of the ink head 4 in the conveyance direction F. The pretreatment liquid head 5 is arranged upstream of the ink head 4 in the conveyance direction F. FIG. 3 shows an example in which one pretreatment liquid head 5 is arranged near the left end of the array of the ink heads 4. Similarly, the post-treatment liquid head 6 is arranged downstream of the ink head 4 in the conveyance direction F. FIG. 3 shows an example in which one post-treatment liquid head 6 is arranged at the right end of the array of the ink heads 4. In other embodiments, a plurality of pretreatment liquid heads 5 or a plurality of post-treatment liquid heads 6 may be arranged. It is desirable that the carriage 3 be provided with at least one pretreatment liquid head 5 and at least one post-treatment liquid head 6 respectively, but in other embodiments, the pretreatment liquid head 5 and the post-treatment liquid head 6 may not be arranged.

[0025] Note that the continuous arrangement of the heads along the main scanning direction S, which is composed of the ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6, is referred to as a row of heads, or simply a row. Also, the continuous arrangement of the heads along the conveyance direction F, which is composed of the ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6, is referred to as a column of heads, or simply a column.

[0026] The pretreatment liquid head 5 discharges a pretreatment liquid for performing predetermined pretreatment on the workpiece W. The pretreatment liquid is discharged from the pretreatment liquid head 5 to a position on the workpiece W where ink has not yet been discharged from the ink head 4. The pretreatment liquid is a non-color-developing treatment liquid that does not develop color even when it adheres to the workpiece W, and is a treatment liquid that exhibits functions such as enhancing the fixing property of ink to the workpiece W and the aggregating property of ink pigments. As such a pretreatment liquid, a treatment liquid in which a binder resin is blended in a solvent, or a treatment liquid in which a cation resin that is positively charged is blended in a solvent, etc. can be used.

[0027] The post-treatment liquid head 6 discharges a post-treatment liquid for performing a predetermined post-treatment on the work W to which ink has adhered. The post-treatment liquid is discharged from the post-treatment liquid head 6 to the position of the work W after the ink has been discharged from the ink head 4. The post-treatment liquid is a non-color-developing treatment liquid that does not develop color even when it adheres to the work W, and is a treatment liquid that exhibits a function of enhancing the fixability and fastness (resistance to rubbing and scratching) of the ink image printed on the work W by the ink head 4. As such a post-treatment liquid, a silicone-based treatment liquid or the like can be used. Note that the post-treatment liquid and the pre-treatment liquid are different treatment liquids. Specifically, the components contained in the post-treatment liquid and the pre-treatment liquid are different.

[0028] Here, the non-color-developing treatment liquid refers to a liquid that is not recognized by the human eye as having developed color when printed alone on a recording medium. The color here includes those with a chroma of 0 such as black, white, and gray. The non-color-developing treatment liquid is basically a transparent liquid. However, for example, when looking at 1 liter of the treatment liquid in a liquid state, it is not completely transparent and may appear slightly white or the like. Such a color is so faint that it cannot be recognized by the human eye as having developed color when printed alone on a recording medium. Note that depending on the type of the treatment liquid, there may be changes such as gloss on the recording medium when printed alone on the recording medium, but such a state is not color development.

[0029] In this embodiment, the pre-treatment liquid and the post-treatment liquid may be discharged onto substantially the entire surface of the work W, or the pre-treatment liquid and the post-treatment liquid may be selectively discharged in accordance with the image to be printed, similar to the ink.

[0030] Next, a case where the pretreatment liquid and the post-treatment liquid are selectively discharged will be described. As described above, on the work W of the portion where color is printed according to the image, the pretreatment liquid, ink, and post-treatment liquid are discharged in this order. In this case, the ink may be one color or a plurality of colors. Basically, the pretreatment liquid and the post-treatment liquid are not discharged to the portion where no color is printed, that is, the portion where ink is not discharged. Note that, in order to adjust the image quality of the printed image, the texture of the work W, etc., a part of the selection of the discharge of the pretreatment liquid and the post-treatment liquid may be made different from the discharge of the ink.

[0031] As shown in FIG. 3, an opening 31H is provided at the location of the head on the head support frame 31. The ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 are assembled to the head support frame 31 so as to be fitted into the respective openings 31H. From each opening 31H, the nozzles disposed on the lower end surfaces of the respective heads 4, 5, 6 are exposed.

[0032] The plurality of sub-tanks 7 are supported by the carriage 3 above the heads 4, 5, 6 via a holding frame (not shown). The plurality of sub-tanks 7 are provided corresponding to each of the heads 4, 5, 6. Ink or the treatment liquid is supplied to each sub-tank 7 from a main tank 90 (described later) in which the ink and the treatment liquid are stored, and these are supplied to each of the heads 4, 5, 6. Each sub-tank 7 and the heads 4, 5, 6 are connected by a pipeline (not shown) in FIG. 3.

[0033] Specifically, the plurality of sub-tanks 7 include a first supply sub-tank 71A to an eighth supply sub-tank 78A, a pretreatment supply sub-tank 7FA, and a post-treatment supply sub-tank 7RA arranged along the main scanning direction S on the rear side. Further, the plurality of sub-tanks 7 include a first recovery sub-tank 71B to an eighth recovery sub-tank 78B, a pretreatment recovery sub-tank 7FB, and a post-treatment recovery sub-tank 7RB arranged along the main scanning direction S on the front side.

[0034] The first supply sub-tank 71A and the first recovery sub-tank 71B, which are located at the leftmost side of the carriage 3, store yellow ink containing pigments. The first supply sub-tank 71A supplies yellow ink to the first upstream ink head 41A and the first downstream ink head 41B (both are also referred to as supply destinations). On the other hand, the first recovery sub-tank 71B stores the yellow ink recovered from the first upstream ink head 41A and the first downstream ink head 41B. As described above, a part of the yellow ink is discharged from the first upstream ink head 41A and the first downstream ink head 41B toward the workpiece W. Similarly, the second supply sub-tank 72A supplies magenta ink to the second upstream ink head 42A and the second downstream ink head 42B. On the other hand, the second recovery sub-tank 72B stores the magenta ink recovered from the second upstream ink head 42A and the second downstream ink head 42B. Each of the other third sub-tanks to the eighth sub-tanks also has the same structure and function as described above.

[0035] In addition, the pre-treatment supply sub-tank 7FA supplies the pre-treatment liquid to the pre-treatment liquid head 5, and the pre-treatment recovery sub-tank 7FB recovers the pre-treatment liquid from the pre-treatment liquid head 5. Also, the post-treatment supply sub-tank 7RA supplies the post-treatment liquid to the post-treatment liquid head 6, and the post-treatment recovery sub-tank 7RB recovers the post-treatment liquid from the post-treatment liquid head 6.

[0036] As described above, the inkjet printer 1 according to the present embodiment is an all-in-one type printer in which three types of heads, namely the ink head 4, the pre-treatment liquid head 5, and the post-treatment liquid head 6, are mounted on a single carriage 3. According to this inkjet printer 1, for example, in the printing process of inkjet printing on a fabric in digital printing, the discharge process of the pre-treatment liquid and the discharge process of the post-treatment liquid can be executed integrally. Therefore, the printing process can be simplified and the printing device can be made more compact.

[0037] Note that the inkjet printer 1 according to the present embodiment performs printing processing on the work W in a serial printing method. Specifically, when the work W has a wide size, printing cannot be performed while continuously feeding the work W. The serial printing method is a printing method that repeats the reciprocating movement of the carriage 3 equipped with the ink heads 4 of each color in the main scanning direction S and the intermittent feeding in the conveying direction F of the work W.

[0038] Specifically, while the carriage 3 moves in the forward path direction, which is one direction in the main scanning direction S, printing of the strip-shaped image is performed. During the main scanning in the forward path direction, the feeding of the work W is stopped. After the printing of the strip-shaped image, the work W is fed out in the conveying direction F by a predetermined pitch. At this time, the carriage 3 waits in the folding area 14 on the left end side. After the work W is fed out, the carriage 3 folds back in the return path direction opposite to the forward path direction along with the reverse movement of the timing belt 16. The work W is in a stopped state. Then, while the carriage 3 moves in the return path direction, the next strip-shaped image is printed upstream of the strip-shaped image. Hereinafter, the same operation is repeated.

[0039] <Regarding the circulation path of ink and processing liquid> Next, the flow of ink and processing liquid in the inkjet printer 1 according to the present embodiment will be described. In the following, the flow of ink will be described in detail, but the same structure is provided for each processing liquid. FIG. 4 is a schematic diagram showing the flow of ink around the liquid ejection head according to the present embodiment. FIG. 5 is a schematic diagram showing the supply sub-tank and the recovery sub-tank according to the present embodiment. In each figure, the lines connecting the members indicate the pipelines (tubes) through which gas and liquid flow.

[0040] In this embodiment, pressure is applied to each of the first supply sub-tanks 71A to the post-treatment supply sub-tank 7RA (each also referred to as a supply tank), the first recovery sub-tanks 71B to the post-treatment recovery sub-tank 7RB (each also referred to as a recovery tank) mounted on the carriage 3 in FIG. 3, via air (an example of a gas). As a result, liquid (ink, pretreatment liquid, post-treatment liquid) is supplied from each supply sub-tank to the ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6. In other embodiments, pressure may be applied to each sub-tank by a gas other than air, and liquid may be supplied.

[0041] Referring to FIG. 4, a circulation path including a supply and recovery path for yellow ink to the first upstream ink head 41A and the first downstream ink head 41B will be described. Note that a structure similar to that of FIG. 4 is also provided for ink heads of other colors. The inkjet printer 1 further includes filters 81, 82, 83, 84 disposed on the carriage 3, a circulation pump 85 (a pump, an ink pump), a check valve 86, and a degasser 87. The inkjet printer 1 further includes a main tank 90 disposed on the apparatus frame 10 (FIG. 1) outside the carriage 3, a capacitance sensor 91, a main tank valve 92, a main supply pump 93, and a control unit 100.

[0042] The yellow ink that has flowed into the ink supply path QA from the first supply sub-tank 71A is branched into a first ink path Q1 passing through the first upstream ink head 41A and a second ink path Q2 passing through the first downstream ink head 41B. The filter 81 is disposed upstream of the first upstream ink head 41A, and the filter 82 is disposed upstream of the first downstream ink head 41B. Further, the filter 83 is disposed downstream of the first upstream ink head 41A, and the filter 84 is disposed downstream of the first downstream ink head 41B. These filters have a function of removing foreign matters, dust, etc. in the ink. After a part of the yellow ink is discharged from the first upstream ink head 41A and the first downstream ink head 41B to the workpiece W, the other ink is recovered from the ink recovery path QB to the first recovery sub-tank 71B. Further, the recovered yellow ink is supplied to the first supply sub-tank 71A through the ink return path Q3.

[0043] As shown in FIG. 4, the circulation pump 85 constitutes a part of the circulation path of the yellow ink that returns from the first supply sub-tank 71A, passes through the first upstream ink head 41A, the first downstream ink head 41B, and the first recovery sub-tank 71B, and returns to the first supply sub-tank 71A. In the present embodiment, the circulation pump 85 feeds the yellow ink from the first recovery sub-tank 71B to the first supply sub-tank 71A. Note that the circulation pump 85, together with the ink circulation path and each sub-tank, constitutes the ink circulation device in the present disclosure.

[0044] The check valve 86 suppresses the backflow of the ink through the ink return path Q3 from the first supply sub-tank 71A to the first recovery sub-tank 71B. The degasser 87 has a function of degassing (removing bubbles) the ink in the ink return path Q3.

[0045] The main tank 90 is mounted on the apparatus frame 10 of the inkjet printer 1 and stores the yellow ink. Note that similar main tanks 90 are provided for other colors as well.

[0046] The capacitance sensor 91 detects the remaining amount of yellow ink in the main tank 90.

[0047] The main tank valve 92 is a valve capable of opening or closing the ink replenishment path Q4 extending from the main tank 90 to the first supply sub-tank 71A. The opening and closing of the main tank valve 92 may be performed manually or automatically according to a command signal input from the control unit 100.

[0048] The main supply pump 93 operates to supply the yellow ink in the main tank 90 to the first supply sub-tank 71A.

[0049] The control unit 100 comprehensively controls the operation of the inkjet printer 1 and electrically controls each member shown in FIG. 4.

[0050] As shown in FIG. 5, as an example, the first supply sub-tank 71A has a box-shaped structure. When yellow ink is stored therein, a supply tank gas region SA and a supply tank ink region SB are formed. The supply tank gas region SA is a space above the liquid level of the yellow ink in the first supply sub-tank 71A, and the supply tank ink region SB is a region formed by the yellow ink. The supply tank gas region SA communicates with the supply-side pressure supply path P11. The supply-side pressure supply path P11 communicates with a pressure source (not shown) and maintains the supply tank gas region SA of the first supply sub-tank 71A at a predetermined pressure. Also, the supply tank ink region SB communicates with the ink supply path QA (the first ink path Q1, the second ink path Q2), the ink return path Q3, and the ink replenishment path Q4, respectively.

[0051] Further, the first supply sub-tank 71A has a capacitance sensor 71A1 capable of detecting the liquid level (ink amount) of the yellow ink in the first supply sub-tank 71A.

[0052] Similarly, the first recovery sub-tank 71B has a box-shaped structure. When yellow ink is stored inside it, a recovery tank gas region SC and a recovery tank ink region SD are formed. The recovery tank gas region SC is a space above the liquid level of the yellow ink in the first recovery sub-tank 71B, and the recovery tank ink region SD is a region formed by the yellow ink. The recovery tank gas region SC communicates with the recovery-side pressure supply path P12. The recovery-side pressure supply path P12 communicates with a pressure source (not shown) and maintains the recovery tank gas region SC of the first recovery sub-tank 71B at a predetermined pressure. Also, the recovery tank ink region SD communicates with the ink recovery path QB (the first ink path Q1, the second ink path Q2) and the ink return path Q3 respectively.

[0053] Also, the first recovery sub-tank 71B has a capacitance sensor 71B1 capable of detecting the liquid level (ink amount) of the yellow ink in the first recovery sub-tank 71B.

[0054] In this embodiment, the supply tank gas region SA of the first supply sub-tank 71A is maintained at, for example, +2 kPa, and the recovery tank gas region SC of the first recovery sub-tank 71B is maintained at, for example, -15 kPa. As a result, a flow of yellow ink is formed from the first supply sub-tank 71A in FIG. 4 through the ink supply path QA (the first ink path Q1, the second ink path Q2) and the ink recovery path QB (the first ink path Q1, the second ink path Q2) to the first recovery sub-tank 71B.

[0055] When the control unit 100 determines that the ink in the first supply sub-tank 71A is low in response to the output signal of the capacitance sensor 71A1 (FIG. 5), the circulation pump 85 in FIG. 4 operates according to the command signal input from the control unit 100. As a result, a part of the yellow ink in the first recovery sub-tank 71B is supplied to the first supply sub-tank 71A through the ink return path Q3. Note that the operation of the above-mentioned circulation pump 85 is performed regardless of whether the printing operation in the inkjet printer 1 is being executed or stopped.

[0056] Further, based on the detection results of the capacitance sensors 71A1 and 71B1, when the control unit 100 determines that the ink amounts of the yellow ink in both the first supply sub-tank 71A and the first recovery sub-tank 71B are below a preset threshold value, the control unit 100 operates the main supply pump 93 to replenish the yellow ink from the main tank 90 to the first supply sub-tank 71A through the ink replenishment path Q4. At this time, the main tank valve 92 opens to adjust the maximum replenishment amount (replenishment speed) for the first supply sub-tank 71A. Also, when the capacitance sensor 91 detects that the remaining amount of the yellow ink in the main tank 90 is low, the control unit 100 causes an ink replenishment message to be displayed on a display unit (not shown) of the inkjet printer 1.

[0057] According to the image formed on the workpiece W, yellow ink is ejected from the first upstream ink head 41A and the first downstream ink head 41B, respectively. Meanwhile, as shown in FIG. 4, the yellow ink circulates through a circulation path formed by the ink supply path QA, the first ink path Q1, the second ink path Q2, the ink recovery path QB, and the ink return path Q3.

[0058] Next, the circulation pump 85 (FIG. 4) and the surrounding structure will be described in further detail. FIG. 6 is a perspective view showing a plurality of circulation pumps 85 and the air supply mechanism 50 according to the present embodiment. The inkjet printer 1 further includes an air supply mechanism 50. The air supply mechanism 50 supplies air to the suction side tank portion 126 and the delivery side tank portion 128 (both are chambers) of the circulation pump 85 described later, and together with the circulation pump 85, constitutes the liquid supply device of the present disclosure.

[0059] In FIG. 6, four circulation pumps 85 for circulating ink in the circulation paths of the four-color ink heads of the first upstream ink head 41A and the first downstream ink head 41B, the second upstream ink head 42A and the second downstream ink head 42B, the third upstream ink head 43A and the third downstream ink head 43B, and the fourth upstream ink head 44A and the fourth downstream ink head 44B shown in FIG. 3 are illustrated. Among these, the circulation pump 85 drawn at the far right front constitutes the circulation path of the yellow ink in FIG. 4 and supplies yellow ink from the first recovery sub-tank 71B to the first supply sub-tank 71A.

[0060] In the present embodiment, one air supply mechanism 50 is commonly provided for the four circulation pumps 85 for the four colors of ink. The air supply mechanism 50 is connected to each tank portion (chamber) of the circulation pump 85. Referring to FIG. 6, the air supply mechanism 50 includes an introduction pipe 50H, a branch pipe 50G, a first pipe 50A, a second pipe 50B, a third pipe 50C, and a fourth pipe 50D. The air supply mechanism 50 also includes four check valves 51, a flow control valve 52 (flow adjustment portion), and a solenoid valve 53.

[0061] The first pipe 50A, the second pipe 50B, the third pipe 50C, and the fourth pipe 50D are pipes for supplying air to the four circulation pumps 85 in FIG. 6. As shown in FIG. 6, in the circulation path of the yellow ink, the first pipe 50A is connected in the middle of the pipe connecting from the first recovery sub-tank 71B to the circulation pump 85. The same applies to the other colors.

[0062] The introduction pipe 50H has an atmospheric pressure communication portion AP at its inlet portion, and air (atmosphere) can be taken in from this atmospheric pressure communication portion AP. The branch pipe 50G is a pipe for causing the air introduced from the introduction pipe 50H to flow into the first pipe 50A, the second pipe 50B, the third pipe 50C, and the fourth pipe 50D, respectively.

[0063] The four check valves 51 are provided corresponding to the circulation pumps 85 of each color, and as shown in FIG. 6, they are provided one by one in the first pipeline 50A, the second pipeline 50B, the third pipeline 50C, and the fourth pipeline 50D. Each check valve 51 prevents the ink from flowing backward from each of the plurality of circulation pumps 85 toward the flow control valve 52 in FIG. 6. As a result, in the branch pipeline 50G, the introduction pipeline 50H, etc., the mixing of inks of different colors (liquids different from each other) is suppressed. In FIG. 6, the description is made using the circulation pumps 85 corresponding to the four-color inks. However, for example, when one of these circulation pumps 85 is a pump corresponding to the pretreatment liquid, if the ink and the pretreatment liquid are mixed in the branch pipeline 50G or the like, aggregates will be generated, and there will be a problem that the branch pipeline 50G will be blocked. The check valve 51 can also prevent such problems from occurring. Further, the aforementioned liquids different from each other may be not only combinations of different colors, but also combinations such as a dye black ink and a pigment black ink.

[0064] The flow control valve 52 is a control valve for adjusting the flow rate of air flowing into each circulation pump 85. The flow control valve 52 is also referred to as a spicon or a speed controller. As an example, when a command signal is input from the control unit 100 in FIG. 4 to the flow control valve 52, the flow control valve 52 opens to adjust the opening degree of the introduction pipeline 50H, and the flow rate of the air is adjusted.

[0065] The solenoid valve 53 can switch the supply of air to each circulation pump 85 and the stop of the supply. As an example, when a command signal is input from the control unit 100 in FIG. 4 to the solenoid valve 53, the solenoid valve 53 opens to switch the opening and closing of the introduction pipeline 50H.

[0066] Note that the flow control valve 52 and the solenoid valve 53 in FIG. 6 constitute an adjustment unit in the present embodiment, which is connected to each circulation pump 85. The adjustment unit can adjust the amount (volume) of air supplied to the chamber of each circulation pump 85.

[0067] FIG. 7 is a schematic horizontal cross-sectional view of the circulation pump 85 according to the present embodiment. FIG. 8 is a schematic longitudinal cross-sectional view of the circulation pump 85.

[0068] As shown in FIG. 7, the circulation pump 85 has a housing 116. The housing 116 has an intake nozzle 120A, a delivery nozzle 122A, a membrane vibrator 118, an intake side tank portion 126, a delivery side tank portion 128, and a pump chamber 130.

[0069] The intake nozzle 120A is connected to a pipeline extending from the first recovery sub-tank 71B (FIGS. 4 and 6). Similarly, the delivery nozzle 122A is connected to a pipeline leading to the first supply sub-tank 71A. An intake port 120 is arranged at the base end portion of the intake nozzle 120A, and a delivery port 122 is arranged at the base end portion of the delivery nozzle 122A.

[0070] Inside the housing 116, an intake-side tank portion 126 communicating with the intake port 120, a delivery-side tank portion 128 communicating with the delivery port 122, and a pump chamber 130 communicating with the intake-side tank portion 126 and the delivery-side tank portion 128 are respectively formed. Note that, as shown in FIG. 8, the intake-side tank portion 126 and the delivery-side tank portion 128 have a semi-circular shape with a slightly concave center in a front view and are symmetric with each other about the left and right. An intake-side check valve 132 is disposed between the intake-side tank portion 126 and the pump chamber 130. This intake-side check valve 132 allows ink (fluid) flowing from the intake-side tank portion 126 toward the pump chamber 130 to pass through the intake-side communication passage 144, but is set not to allow ink to pass in the reverse direction. Similarly, a delivery-side check valve 134 is disposed between the delivery-side tank portion 128 and the pump chamber 130. This delivery-side check valve 134 allows ink flowing from the pump chamber 130 toward the delivery-side tank portion 128 to pass through the delivery-side communication passage 146, but is set not to allow ink to pass in the reverse direction. A part of the wall constituting the pump chamber 130 is formed by the diaphragm vibrator 118. The diaphragm vibrator 118 includes a piezoelectric element 118a and bends in a direction according to the polarity of the voltage when a voltage is applied to the piezoelectric element 118a. Then, when a periodic voltage is applied to the piezoelectric element 118a, the diaphragm vibrator 118 vibrates, and the volume of the pump chamber 130 periodically repeats expansion and contraction.

[0071] When the membrane oscillator 118 bends downward in Fig. 7 and the volume of the pump chamber 130 expands, the pressure in the pump chamber 130 decreases, the suction-side check valve 132 opens, and the ink in the suction-side tank portion 126 is drawn into the pump chamber 130. At this time, since the delivery-side check valve 134 is maintained in the closed state, ink does not flow into the pump chamber 130 from the delivery-side tank portion 128. Next, when the membrane oscillator 118 bends upward in Fig. 7 and the volume of the pump chamber 130 contracts, the pressure in the pump chamber 130 increases, the delivery-side check valve 134 opens, and the ink in the pump chamber 130 is sent out into the delivery-side tank portion 128. At this time, since the suction-side check valve 132 is maintained in the closed state, ink does not flow into the suction-side tank portion 126 from the pump chamber 130. In this way, as the membrane oscillator 118 vibrates and the expansion and contraction of the volume of the pump chamber 130 are repeated, ink is sucked in from the suction port 120 and sent out from the delivery port 122.

[0072] As described above, when an alternating voltage is applied to the membrane oscillator 118 to vibrate the membrane oscillator 118, ink is sucked in from the suction port 120, and the suction-side tank portion 126 and the delivery-side tank portion 128 are filled with ink. However, when it is filled with ink to a certain extent, the liquid levels L1 and L2 of each tank portion no longer rise, and air pockets A1 and A2 (gas pockets) are formed in the upper spaces of the suction-side tank portion 126 and the delivery-side tank portion 128, respectively, as shown in Fig. 8.

[0073] The flow rate of the ink sent out from the delivery port 122 can be increased by increasing the voltage of the alternating voltage applied to the membrane oscillator 118 to increase the amplitude of the membrane oscillator 118, or by increasing the frequency of the alternating voltage to increase the vibration period of the membrane oscillator 118. As an example, the circulation pump 85 is driven at a frequency of about 20 Hz to 120 Hz.

[0074] In the circulation pump 85 as described above, when ink is sent out from the pump chamber 130, the pump chamber 130 contracts and the inside of the pump chamber 130 is pressurized, and the ink is sent out from the inside of the pump chamber 130 toward the delivery port 122. However, when the fluid resistance on the delivery port 122 side is large, it becomes impossible to send out a sufficient amount of ink from the pump chamber 130. Also, when ink is sucked into the pump chamber 130, a similar phenomenon occurs, and when the fluid resistance on the suction port 120 side is large, it becomes impossible to suck a sufficient amount of ink into the pump chamber 130. That is, due to the increase in the fluid resistance at the delivery port 122 and the suction port 120, the performance of the circulation pump 85 deteriorates.

[0075] In response to such a problem, in the present embodiment, a suction-side tank portion 126 and a delivery-side tank portion 128 are provided on the suction port 120 side and the delivery port 122 side, respectively. As described above, air pockets A1 and A2 are formed in each tank portion. Such air pockets A1 and A2 have a so-called damper function. Specifically, when sucking ink, the air in the suction-side tank portion 126 temporarily expands, so that the resistance when the ink is sucked from the suction-side tank portion 126 into the pump chamber 130 becomes small. Also, when sending out ink, the air in the delivery-side tank portion 128 temporarily contracts, so that the resistance when sending out the ink from the pump chamber 130 into the delivery-side tank portion 128 becomes small. Thereby, even when the fluid resistance at the suction port 120 and the delivery port 122 increases, it is possible to prevent the performance of the circulation pump 85 from deteriorating.

[0076] On the one hand, FIG. 9 is a graph showing the temporal change in the delivery flow rate of the circulation pump 85 when the air supply mechanism 50 according to the present embodiment is not provided, and shows the results of two experiments. Even when the film vibrator 118 is vibrated under the same conditions, it is confirmed that the delivery flow rate decreases over time. When visually checking the air pockets A1 and A2 in the suction side tank portion 126 and the delivery side tank portion 128 at this time, it is confirmed that each air pocket is shrinking, and for example, air is decreasing due to the discharge of bubbles or the like. Thus, when the delivery flow rate of the circulation pump 85 changes over time, the circulation amount of the ink from the first recovery sub-tank 71B to the first supply sub-tank 71A fluctuates, and it becomes difficult to supply the ink to each ink head at a stable flow rate. Therefore, in order to stably maintain the damping function as described above, it is necessary to continuously ensure the volumes of the air pockets A1 and A2 in the suction side tank portion 126 and the delivery side tank portion 128.

[0077] In the present embodiment, in order to solve the above problems, the inkjet printer 1 has the above-described air supply mechanism 50. The circulation pump 85 has a suction port 120 (suction port) for receiving ink, a suction side tank portion 126 and a delivery side tank portion 128 (both are chambers) for accommodating the received ink together with the air pockets A1 and A2, and a delivery port 122 for delivering the ink accommodated in the tank portion. The air supply mechanism 50 can supply air to the suction side tank portion 126 and the delivery side tank portion 128 of the circulation pump 85.

[0078] According to such a configuration, since the circulation pump 85 has the air pockets A1 and A2, even if the fluid resistance at the suction port 120 and the delivery port 122 increases, it is possible to prevent the performance of the circulation pump 85 from deteriorating thereby. Further, the air supply mechanism 50 makes it difficult for the air in the suction side tank portion 126 and the delivery side tank portion 128 of the circulation pump 85 to be insufficient, and the delivery flow rate of the circulation pump 85 can be stably maintained.

[0079] Further, in the present embodiment, since the circulation pump 85 is disposed in the ink flow path that returns from the first supply sub-tank 71A to the first supply sub-tank 71A via each ink head, the ink flow between each ink head and the first supply sub-tank 71A can be stably controlled.

[0080] In particular, the circulation pump 85 is disposed so as to send out ink in a portion (a predetermined portion of the flow path) from each ink head to the first supply sub-tank 71A in the flow path. For this reason, the bubbles discharged from the circulation pump 85 are less likely to flow to each ink head. In this case, the bubbles include both the air originally contained in the circulation pump 85 and the air supplied from the air supply mechanism 50. In other embodiments, the circulation pump 85 may be disposed in a portion of the flow path from the first supply sub-tank 71A to each ink head. In this case, it is desirable to dispose a member capable of removing the bubbles.

[0081] Also, in the present embodiment, the circulation pump 85 receives ink from the first recovery sub-tank 71B at the suction port 120 and sends out the ink from the discharge port 122 toward the first supply sub-tank 71A. And the air supply mechanism 50 is connected to a portion between the first recovery sub-tank 71B and the suction port 120 in the ink flow path as shown in FIG. 6.

[0082] According to such a configuration, air can be supplied to the suction-side tank portion 126 and the discharge-side tank portion 128 of the circulation pump 85 along the ink flow from the first recovery sub-tank 71B to the circulation pump 85. In other words, compared with the case where the air supply mechanism 50 is connected to a portion between the discharge port 122 and the first supply sub-tank 71A in the ink flow path, the inflow of air into the first supply sub-tank 71A is blocked, and air can be reliably supplied to the suction-side tank portion 126 and the discharge-side tank portion 128.

[0083] In addition, in the present embodiment, since the air supply mechanism 50 has an adjustment unit capable of adjusting the amount of air supplied to the suction side tank portion 126 and the discharge side tank portion 128, it is possible to prevent an excessive amount of air from being supplied to each tank portion and to prevent poor air replenishment.

[0084] Furthermore, in the present embodiment, the adjustment unit includes a solenoid valve 53 capable of switching between supplying air to the suction side tank portion 126 and the discharge side tank portion 128 and stopping the supply. Therefore, by opening and closing the solenoid valve 53, it is possible to easily switch the air supply to the circulation pump 85.

[0085] In addition, in the present embodiment, the adjustment unit includes a flow control valve 52 capable of adjusting the flow rate of air flowing into the suction side tank portion 126 and the discharge side tank portion 128. By adjusting the air flow rate with the flow control valve 52 in this way, it is possible to quickly replenish the suction side tank portion 126 and the discharge side tank portion 128 with air at a large flow rate, while gradually replenishing air at a small flow rate as needed.

[0086] Furthermore, in the present embodiment, the inkjet printer 1 includes a plurality of circulation pumps 85, and the adjustment unit is provided so as to be shared by the plurality of circulation pumps 85. Therefore, the number of the adjustment units can be reduced, and the cost of the inkjet printer 1 including the air supply mechanism 50 can be reduced.

[0087] In addition, in the present embodiment, each check valve 51 prevents ink from flowing backward from the circulation pump 85 toward the adjustment unit, so that mixing of inks of different colors is suppressed. Also, when some of the circulation pumps 85 supply a pretreatment liquid, it is possible to suppress the generation of aggregates due to mixing of the ink and the pretreatment liquid and to prevent a part of the pipeline from being blocked.

[0088] Furthermore, in the present embodiment, the pressure of the recovery tank exemplified by the first recovery sub-tank 71B is set to a negative pressure, and the electromagnetic valve 53 is controlled to be closed during the stop of the circulation pump 85 and opened during the drive of the circulation pump 85. As a result, due to the difference between the atmospheric pressure and the pressure of the first recovery sub-tank 71B when the electromagnetic valve 53 is opened, air can be supplied to the suction-side tank portion 126 and the delivery-side tank portion 128.

[0089] When controlling the air supply mechanism 50 described above, two main methods can be adopted. When simply supplying air to the circulation pump 85, the reduction of bubbles in the circulation pump 85 is grasped in advance through experiments or the like. From the elapsed time after the start of use, the total amount of ink flow rate delivered, the operating time of the circulation pump 85, etc., the electromagnetic valve 53 can be opened at intervals where the pump performance does not decrease significantly to send gas into the circulation pump 85. The amount of gas supplied can be estimated from the pressure difference between the negative pressure generated by the pump operation and the atmospheric pressure and the flow path resistance. A slightly larger amount of gas is sent in order to prevent the air in the circulation pump 85 from decreasing below the expected reduction amount. At this time, the opening time of the electromagnetic valve 53 may be simply set to a constant, or the electromagnetic valve 53 may be controlled to achieve a fixed quantity. Even if gas overflows from the circulation pump 85 due to an excessive amount of gas supplied, there will be no problem because it simply flows into the first supply sub-tank 71A. Also, if the flow path resistance in the supply path is adjusted so that the gas flow rate when the electromagnetic valve 53 is opened does not increase, both the recovery of the efficiency of the circulation pump 85 and the pressure fluctuation of the supply sub-tank 71A caused by the inflow of gas will be gentle. Therefore, these phenomena can be adjusted within the control range of normal ink circulation, so gas can be supplied while continuing printing.

[0090] Furthermore, when finer control than the above control method is desired, gas may be supplied when a predetermined efficiency decrease is detected for the circulation pump 85 based on the parameter controlling the ink circulation. As described above, when the gas supply is shared among the plurality of circulation pumps 85, when an efficiency decrease is detected in any one of the circulation pumps 85, gas is supplied to all the circulation pumps 85. The concept of the gas supply amount at this time is the same as in the case of the above-described simple control. However, if it is detected that the efficiency of one circulation pump 85 has significantly decreased, the gas supply amount may be increased in accordance with the decrease. Also, if the efficiency of the circulation pump 85 does not recover after the gas supply, a warning to that effect may be given on a display unit (not shown) of the inkjet printer 1 or the like. Detection and warning of such non-recovery of the circulation pump 85 may be applied to the previous embodiment.

[0091] According to the inkjet printer 1 (inkjet recording apparatus) including the liquid supply device according to the present embodiment as described above, the supply of ink or the processing liquid to each head can be stably performed. Also, by circulating the ink, it is possible to eliminate waste of the ink. Note that the present disclosure is not limited to the above embodiment, and can take the following forms.

[0092] (1) The ink head 4 is not limited to being arranged in two rows in the carriage 3. The ink head 4 may be in one row or three or more rows. Also, the inkjet printer 1 is not limited to a configuration capable of discharging a plurality of colors of ink onto the work W, and may be one that discharges a single color of ink.

[0093] (2) In the above embodiment, the inkjet printer 1 may not have a pretreatment liquid head 5 that discharges a pretreatment liquid, a post-treatment liquid head 6 that discharges a post-treatment liquid, and members related thereto.

[0094] (3) In the above-described embodiment, the recovery tank is provided in the ink circulation path. However, the recovery tank may not be provided. In this case, the ink circulation path is provided so as to return from the supply tank to the supply tank via the ink head (supply destination). Then, the circulation pump 85 forms a part of the circulation path and sends out the ink.

[0095] (4) A plurality of configurations respectively disclosed in the above-described embodiments can be combined with each other to constitute one disclosure.

Explanation of Reference Numerals

[0096] 1 Inkjet printer (inkjet recording apparatus) 116 Housing 118 Film-like vibrator 118a Piezoelectric element 120 Suction port 122 Delivery port 126 Suction-side tank portion (chamber) 128 Delivery-side tank portion (chamber) 130 Pump chamber 132 Suction-side check valve 134 Delivery-side check valve 144 Suction-side communication path 146 Delivery-side communication path 3 Carriage 4 Ink head 41A First upstream ink head 41B First downstream ink head 42A Second upstream ink head 42B Second downstream ink head 5 Pretreatment liquid head 50 Air supply mechanism 50A First pipeline 50B Second pipeline 50C Third pipeline 50D Fourth pipeline 50G Branch pipeline 50H Introduction pipeline 51 Check valve 52 Flow control valve (adjustment unit, flow rate adjustment unit) 53 Electromagnetic valve (adjustment unit) 6 Post-treatment liquid head 7 Sub-tank 71A First supply sub-tank (supply tank) 71B First recovery sub-tank (recovery tank) 72A Second supply sub-tank 72B Second recovery sub-tank 85 Circulation pump (pump) 90 Main tank 91 Capacitance sensor 92 Main tank valve 93 Main supply pump A1, A2 Air pockets AP Atmospheric pressure communication part L1, L2 Liquid levels

Claims

1. At least one pump having a liquid inlet for receiving a liquid, a first chamber for receiving the received liquid together with a gas reservoir, a pump chamber communicating with the first chamber, a second chamber communicating with the pump chamber for receiving the liquid together with the gas reservoir, and a liquid outlet for discharging the liquid received in the second chamber. An air supply mechanism capable of supplying gas to the first chamber and the second chamber. A liquid supply device comprising the same.

2. At least one pump having a liquid inlet for receiving a liquid, a chamber for receiving the received liquid together with a gas reservoir, and a liquid outlet for discharging the liquid received in the chamber. An air supply mechanism capable of supplying gas to the chamber. A supply tank for storing the liquid supplied to the supply destination. A flow path of the liquid that returns from the supply tank to the supply tank via the supply destination. Comprising The pump discharges the liquid at a predetermined part of the flow path. A liquid supply device.

3. The liquid supply device according to Claim 2, The pump discharges the liquid in a part of the flow path from the supply destination to the supply tank. A liquid supply device.

4. The liquid supply device according to Claim 3, Further comprising a recovery tank disposed in the flow path for storing the liquid recovered from the supply destination. The pump receives the liquid from the recovery tank at the liquid inlet and discharges the liquid from the liquid outlet toward the supply tank. The air supply mechanism is connected to a part of the flow path of the liquid between the recovery tank and the liquid inlet. A liquid supply device.

5. The liquid supply device according to Claim 2, The air supply mechanism includes an adjustment unit capable of adjusting the amount of gas supplied to the chamber. A liquid supply device.

6. At least one pump having a liquid inlet for receiving a liquid, a chamber for receiving the received liquid together with a gas reservoir, and a liquid outlet for discharging the liquid received in the chamber. An air supply mechanism capable of supplying gas to the chamber. Comprising The air supply mechanism includes an adjustment unit capable of adjusting the amount of gas supplied to the chamber. The adjustment unit includes a solenoid valve capable of switching between supplying gas to the chamber and stopping the supply. A liquid supply device.

7. The liquid supply device according to Claim 5 or 6, The liquid supply device, wherein the adjustment unit includes a flow rate adjustment unit capable of adjusting the flow rate of the gas flowing into the chamber.

8. At least one pump having a suction port for receiving a liquid, a chamber for accommodating the received liquid together with a gas reservoir, and a discharge port for discharging the liquid accommodated in the chamber; a gas supply mechanism capable of supplying gas to the chamber. The gas supply mechanism includes an adjustment unit capable of adjusting the amount of gas supplied to the chamber. The at least one pump includes a plurality of pumps. The adjustment unit is provided so as to be shared by the plurality of pumps. Liquid supply device.

9. The liquid supply device according to claim 8, each of the plurality of pumps discharges a different liquid, The gas supply mechanism further includes a plurality of check valves that prevent the liquid from flowing backward from each of the plurality of pumps toward the adjustment unit. Liquid supply device.

10. The liquid supply device according to claim 6, further comprising a recovery tank disposed in the flow path of the liquid for storing the liquid recovered from the supply destination, and the pressure of the recovery tank is set to a negative pressure. The solenoid valve is closed during the stop of the pump and opened during the drive of the pump. Liquid supply device.

11. An ink head for discharging ink onto a recording medium; The liquid supply device according to any one of claims 1 to 10, which supplies the ink as the liquid to the ink head; An inkjet recording apparatus comprising:

12. Delivering the liquid by at least one pump having a suction port for receiving the liquid, a first chamber for accommodating the received liquid together with a gas reservoir, a pump chamber communicating with the first chamber, a second chamber communicating with the pump chamber and accommodating the liquid together with a gas reservoir, and a discharge port for discharging the liquid accommodated in the second chamber; supplying gas to the first chamber and the second chamber by a gas supply mechanism; A liquid supply method comprising:

13. Arranging a flow path of the liquid that returns from the supply destination to the supply tank via the supply destination from a supply tank that stores the liquid to be supplied to the supply destination. Dispose at least one pump having a liquid inlet for receiving a liquid, a chamber for accommodating the received liquid together with a gas reservoir, and a liquid outlet for discharging the liquid accommodated in the chamber at a predetermined portion of the flow path, and discharge the liquid by the at least one pump, Supply gas to the chamber by an air supply mechanism, A liquid supply method comprising.

14. A liquid supply method according to claim 13, The liquid supply method, wherein the pump is disposed in a portion of the flow path from the supply destination to the supply tank, and the liquid is discharged.

15. A liquid supply method according to claim 13, In the flow path, further dispose a recovery tank for storing the liquid recovered from the supply destination, The pump receives the liquid from the recovery tank at the liquid inlet and discharges the liquid from the liquid outlet toward the supply tank, The liquid supply method, wherein the air supply mechanism is connected to a portion between the recovery tank and the liquid inlet in the liquid flow path. Discharging a liquid by at least one pump having a liquid inlet for receiving a liquid, a chamber for accommodating the received liquid together with a gas reservoir, and a liquid outlet for discharging the liquid accommodated in the chamber, Supplying gas to the chamber by an air supply mechanism including an adjustment unit capable of adjusting the amount of gas supplied to the chamber, Switching, by the adjustment unit, the supply of gas to the chamber and the stop of the supply, A liquid supply method comprising.

17. Discharging a liquid by a plurality of pumps each having a liquid inlet for receiving a liquid, a chamber for accommodating the received liquid together with a gas reservoir, and a liquid outlet for discharging the liquid accommodated in the chamber, Supplying gas to the chamber by an air supply mechanism including an adjustment unit capable of adjusting the amount of gas supplied to the chamber, The liquid supply method, wherein the adjustment unit is provided so as to be shared by the plurality of pumps. A liquid supply method comprising.

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