Recording device

Abstract

A pressure measurement device (1S) is for measuring the pressure of a plurality of pressure transmission paths for applying pressure to an object via a gas and comprises: at least one pressure measurement unit (1A) including a measurement path having an internal space capable of receiving the gas, and a pressure sensor (611) for detecting the pressure in the internal space; and at least one switching unit (63) capable of selectively switching the connection destination of the measurement path from among the plurality of pressure transmission paths.

Description

Pressure measuring device and recording device equipped with the same

[0001] The present disclosure relates to a pressure measuring device and a recording device including the same.

[0002] Japanese Patent Laid-Open No. 2006-129999 discloses a recording apparatus including a liquid ejection mechanism that ejects liquid onto a recording medium to form an image. The liquid ejection mechanism includes a liquid ejection head, a movable stage that supports the liquid ejection head and is movable in the main scanning direction, and a pressure measurement device disposed on the movable stage. The pressure measurement device measures the pressure of the liquid inside the liquid ejection head and includes a pressure transmission path that communicates with the liquid ejection head and a pressure sensor that can measure the pressure in the pressure transmission path.

[0003] JP 2010-52357 A

[0004] An object of the present disclosure is to provide a pressure measuring device that is capable of measuring the pressure in a pressure transmission path using a number of pressure sensors that is fewer than the number of pressure transmission paths, and a recording device that includes the same.

[0005] A pressure measuring device according to one aspect of the present disclosure is a pressure measuring device that measures the pressure of a plurality of pressure transmission paths that apply pressure to an object via gas, and is equipped with at least one pressure measuring unit that includes a measurement path having an internal space capable of receiving the gas and a pressure sensor that detects the pressure in the internal space, and at least one switching unit that is capable of selectively switching the connection destination of the measurement path from among the plurality of pressure transmission paths.

[0006] Furthermore, a recording device according to another aspect of the present disclosure includes the pressure measurement device described above, the plurality of pressure transmission paths, and at least one liquid ejection unit that ejects liquid onto a recording material, and each of the plurality of pressure transmission paths applies the pressure to the liquid supplied to the at least one liquid ejection unit or the liquid recovered from the at least one liquid ejection unit.

[0007] FIG. 1 is a perspective view showing the overall configuration of a recording apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is an enlarged perspective view of a carriage shown in FIG. 1. FIG. 4 is a schematic diagram showing multiple pressure transmission paths around a carriage according to an embodiment of the present disclosure. FIG. 5 is a schematic diagram showing a supply sub-tank and a recovery sub-tank according to an embodiment of the present disclosure. FIG. 6 is a schematic diagram showing the flow of liquid around a liquid ejection head according to an embodiment of the present disclosure. FIG. 7 is a schematic diagram corresponding to FIG. 4 showing a state during liquid ejection. FIG. 8 is a schematic diagram corresponding to FIG. 4 showing a state during a purge operation.

[0008] A pressure measuring device and a recording device according to each embodiment of the present disclosure will be described below with reference to the drawings. In the following embodiments, an inkjet printer equipped with an ink head that ejects ink for forming an image on a wide, long recording medium will be exemplified as a specific example of a recording device. Inkjet printers are suitable for digital textile printing, which uses an inkjet method to print images such as letters and patterns on a recording medium made of fabric such as woven or knitted fabric. Of course, the recording device according to the present disclosure can also be used to print various images on recording media such as paper sheets and resin sheets.

[0009] [Overall configuration of inkjet printer] Figure 1 is a perspective view showing the overall configuration of an inkjet printer 1 according to a first embodiment of the present disclosure, and Figure 2 is a schematic cross-sectional view taken along line II-II in Figure 1. The inkjet printer 1 is a printer that prints images on a wide and long workpiece W (recording medium) using an inkjet method, and includes a device frame 10, and a workpiece transport unit 20 (transport unit) and carriage 3 that are incorporated into this device frame 10. Note that in this embodiment, the left-to-right direction is the main scanning direction S (Figure 3) when printing on the workpiece W, and the direction from rear to front is the sub-scanning direction (the transport direction F of the workpiece W, which intersects with the main scanning direction S).

[0010] The device frame 10 forms a framework for mounting various components of the inkjet printer 1. The work transport unit 20 is a mechanism that intermittently feeds (transports) the work W so that the work W progresses in a transport direction F from rear to front in a printing area where inkjet printing processing is performed. The carriage 3 is equipped with an ink head 4, a pre-treatment liquid head 5, a post-treatment liquid head 6, and a sub-tank 7, and moves back and forth in a main scanning direction S (left and right direction) that intersects with the transport direction F of the work W during the inkjet printing processing.

[0011] 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-to-right width corresponding to the work transport section 20. The right frame 112 and left frame 113 are erected to the right and left of the central frame 111, respectively. Between the right frame 112 and the left frame 113 is the printing area 12 where printing processing is performed on the work W.

[0012] The right frame 112 forms the maintenance area 13. The maintenance area 13 is an area where the carriage 3 is retracted when the printing process is not being performed. In the maintenance area 13, cleaning processes, purging processes, etc. are performed on the nozzles (ejection holes) of the ink heads 4, pre-treatment liquid heads 5, and post-treatment liquid heads 6, and caps are also fitted. The left frame 113 forms a turn-back area 14 for the carriage 3. The turn-back area 14 is an area where the carriage 3 temporarily enters when it performs a main scan in the opposite direction after main scanning the printing area 12 from right to left during the printing process.

[0013] A carriage guide 15 for moving the carriage 3 back and forth in the left-right direction is attached to the upper side of the device frame 10. The carriage guide 15 is a flat plate-shaped member that is long in the left-right direction, and is disposed above the work transport unit 20. A timing belt 16 is attached to the carriage guide 15 so as to be able to move in a circular motion in the left-right direction (main scanning direction). The timing belt 16 is an endless belt that is driven to move in a circular motion in the left or right direction.

[0014] The carriage guide 15 is equipped with a pair of upper and lower guide rails 17 that extend parallel to the left and right and that hold the carriage 3 in a state that allows it to move back and forth in the main scanning direction S. The carriage 3 is engaged with the guide rails 17. The carriage 3 is also fixed to a timing belt 16. As the timing belt 16 moves orbitally leftward or rightward, the carriage 3 moves leftward or rightward along the carriage guide 15 while being guided by the guide rails 17.

[0015] Referring primarily to Figure 2, the work transport section 20 includes a feed roller 21 that pays 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 located at the rear lower part of the device frame 10, and is a take-up shaft for a feed roll WA that is a roll of the work W before printing. The take-up roller 22 is located at the front lower part of the device frame 10, and is a take-up shaft for a take-up roll WB that is a roll of the work W after the printing process. A first motor M1 is attached to the take-up roller 22, which drives the take-up roller 22 to rotate about its axis and perform the operation of winding up the work W.

[0016] The path between the delivery roller 21 and the take-up roller 22 and passing through the printing area 12 is the transport path for the workpiece W. Arranged on this transport path, in order from upstream, are a first tension roller 23, a work guide 24, a transport roller 25 and a pinch roller 26, a turn-back roller 27, and a second tension roller 28. The first tension roller 23 applies a predetermined tension to the workpiece W on the upstream side of the transport roller 25. The work guide 24 changes the transport direction of the workpiece W from upward to forward, allowing the workpiece W to enter the printing area 12.

[0017] The transport roller 25 is a roller that generates a transport force that intermittently feeds the workpiece W in the printing area 12. The transport roller 25 is driven to rotate around its axis by the second motor M2, and intermittently transports the workpiece W forward (in a predetermined transport direction F) so that the workpiece W passes through the printing area 12 (image forming position) facing the carriage 3. The pinch roller 26 is disposed opposite the transport roller 25 from above, and forms a transport nip portion with the transport roller 25.

[0018] The turn-back roller 27 changes the transport direction of the workpiece W that has passed through the printing area 12 from forward to downward, and guides the workpiece W after printing processing to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W downstream of the transport roller 25. A platen 29 is disposed below the transport path of the workpiece W in the printing area 12.

[0019] The carriage 3 is cantilevered on the guide rails 17 and moves back and forth in a main scanning direction S (left and right in this embodiment) that intersects (orthogonal in this embodiment) with the transport direction F. The carriage 3 includes a carriage frame 30, and an ink head 4, a pre-treatment liquid head 5, a post-treatment liquid head 6, and a sub-tank 7 ( FIG. 3 ) that are mounted on the carriage frame 30. The carriage frame 30 includes a head support frame 31 and a back frame 32.

[0020] The head support frame 31 is a horizontal plate that holds the 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. The guide rail 17 is engaged with the back frame 32. That is, in this embodiment, the back frame 32 is an engagement portion that holds the guide rail 17 in a cantilevered state. The head support frame 31 is a horizontal plate whose rear end is supported in a cantilevered state on the guide rail 17 by the engagement portion.

[0021] The cantilevered state refers to a state in which the engagement portion (back frame 32), which is the portion of the carriage 3 that is held by the guide rail 17, which is a holding member, is present only on one side, either upstream or downstream, from the center of the carriage 3 in the transport direction F, and no other engagement portion is present on the opposite side of the side where the engagement portion is present. The engagement portion may also be located outside the range in which the ink head 4 and processing head are arranged in the transport direction F. In other words, the engagement portion may be located only upstream or only downstream of the range in which the ink head 4 and processing head are arranged in the transport direction F.

[0022] [Details of Carriage] The carriage 3 will now be further described. Fig. 3 is an enlarged perspective view of the carriage 3 shown in Fig. 1. Fig. 3 shows the transport direction F (sub-scanning direction) of the workpiece W and the main scanning direction S, which is the direction of movement of the carriage 3. Fig. 3 shows an example in which the carriage 3 is equipped with a plurality of ink heads 4 that eject ink for image formation onto the workpiece W, a pre-treatment liquid head 5 and a post-treatment liquid head 6 that eject non-color-forming treatment liquid, and a plurality of sub-tanks 7 that supply the ink and treatment liquid to these heads 4 to 6.

[0023] Each ink head 4 has a number of nozzles (ink ejection holes) that eject ink droplets using an ejection method such as a piezoelectric method using a piezoelectric element or a thermal method using a heating element, and ink passages that guide the ink to the nozzles. For example, a water-based pigment ink containing a water-based solvent, pigment, and binder resin can be used as the ink. The multiple ink heads 4 in this embodiment are capable of ejecting eight colors of ink. The ink heads 4 are mounted on the head support frame 31 of the carriage 3 so as to be aligned in two rows in the main scanning direction S. Each color ink head 4 has two heads.

[0024] Specifically, the ink heads 4 include a first upstream ink head 41A and a first downstream ink head 41B. These ink heads 4 eject yellow ink. The ink heads 4 also include a second upstream ink head 42A and a second downstream ink head 42B. These ink heads 4 eject magenta ink. Similarly, as shown in FIG. 3, two ink heads 4 that eject ink of the same color are arranged at positions offset from each other in the transport direction F and the main scanning direction S. These two ink heads 4 form a group, and a total of eight groups of ink heads 4 (41A to 48A, 41B to 48B) eject inks of different colors.

[0025] The pre-treatment liquid head 5 and the post-treatment liquid head 6 are disposed at positions different from the ink heads 4 in the transport direction F. The pre-treatment liquid head 5 is disposed upstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one pre-treatment liquid head 5 is disposed near the left end of the array of ink heads 4. Similarly, the post-treatment liquid head 6 is disposed downstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one post-treatment liquid head 6 is disposed at the right end of the array of ink heads 4. In other embodiments, a plurality of pre-treatment liquid heads 5 or a plurality of post-treatment liquid heads 6 may be disposed. It is desirable that the carriage 3 be equipped with at least one pre-treatment liquid head 5 and at least one post-treatment liquid head 6, but in other embodiments, a pre-treatment liquid head 5 and a post-treatment liquid head 6 may not be disposed.

[0026] A series of heads arranged along the main scanning direction S, which are made up of the ink heads 4, pretreatment liquid heads 5, and posttreatment liquid heads 6, will be referred to as a row of heads, or simply as a row. Also, a series of heads arranged along the transport direction F, which are made up of the ink heads 4, pretreatment liquid heads 5, and posttreatment liquid heads 6, will be referred to as a row of heads, or simply as a row.

[0027] The pretreatment liquid head 5 ejects a pretreatment liquid for performing a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the ink head 4 onto a position on the workpiece W to which ink has not yet been ejected from the ink head 4. The pretreatment liquid is a non-color-forming 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 increasing the fixation of ink to the workpiece W or the coagulation of ink pigments. Examples of such pretreatment liquids that can be used include a treatment liquid in which a binder resin is blended into a solvent, or a treatment liquid in which a positively charged cationic resin is blended into a solvent.

[0028] The post-treatment liquid head 6 ejects a post-treatment liquid for performing a predetermined post-treatment on the workpiece W to which ink has adhered. The post-treatment liquid is ejected from the post-treatment liquid head 6 onto a position on the workpiece W after the ink has been ejected from the ink head 4. The post-treatment liquid is a non-color-forming treatment liquid that does not develop color even when it adheres to the workpiece W, and exhibits the function of increasing the fixation and robustness (resistance to rubbing and scraping) of the ink image printed on the workpiece W by the ink head 4. A silicone-based treatment liquid or the like can be used as such a post-treatment liquid. Note that the post-treatment liquid and the pre-treatment liquid are different treatment liquids. Specifically, the post-treatment liquid and the pre-treatment liquid contain different components.

[0029] Here, a non-color-forming treatment liquid refers to a treatment liquid that, when printed alone on a recording medium, is not perceived as having a color by the naked eye. Colors here include colors with a saturation of zero, such as black, white, and gray. A non-color-forming treatment liquid is essentially a transparent liquid; however, when viewed in its liquid state, for example, 1 liter of treatment liquid may not be completely transparent, but may appear slightly white. Such colors are so faint that, when printed alone on a recording medium, they are not perceived as having a color by the naked eye. Note that, depending on the type of treatment liquid, when printed alone on a recording medium, changes such as gloss may appear on the recording medium, but such a state is not considered color-forming.

[0030] In this embodiment, the pre-treatment liquid and the post-treatment liquid may be ejected onto almost the entire surface of the workpiece W, or the pre-treatment liquid and the post-treatment liquid may be ejected selectively in accordance with the image to be printed, similar to ink.

[0031] Next, a case where the pretreatment liquid and the posttreatment liquid are selectively ejected will be described. As described above, the pretreatment liquid, ink, and posttreatment liquid are ejected in this order onto the portion of the workpiece W where a color is to be printed in accordance with the image. In this case, the ink may be of one color or multiple colors. In portions where no color is to be printed, i.e., portions where no ink is ejected, the pretreatment liquid and the posttreatment liquid are basically not ejected either. Note that, in order to adjust the image quality of the image to be printed and the texture of the workpiece W, the selection of ejection of the pretreatment liquid and the posttreatment liquid may be made to differ from the ejection of the ink.

[0032] 3, openings 31H are provided at the positions where the heads are arranged in the head support frame 31. The ink heads 4, the pre-treatment liquid heads 5, and the post-treatment liquid heads 6 are attached to the head support frame 31 so as to be fitted into the respective openings 31H. Nozzles arranged on the lower end surfaces of the heads 4, 5, and 6 are exposed from the respective openings 31H.

[0033] The plurality of sub-tanks 7 are supported by the carriage 3 above the heads 4, 5, and 6 via a holding frame (not shown). The plurality of sub-tanks 7 are provided corresponding to each of the heads 4, 5, and 6. Ink or treatment liquid is supplied to each sub-tank 7 from a main tank 90 (described below) that contains ink and treatment liquid, and these are supplied to each of the heads 4, 5, and 6. Each sub-tank 7 and the heads 4, 5, and 6 are connected by pipes (not shown in FIG. 3).

[0034] Specifically, the multiple subtanks 7 include a first supply subtank 71A to an eighth supply subtank 78A, a pre-processing supply subtank 7FA, and a post-processing supply subtank 7RA, which are arranged on the rear side along the main scanning direction S. Furthermore, the multiple subtanks 7 include a first recovery subtank 71B to an eighth recovery subtank 78B, a pre-processing recovery subtank 7FB, and a post-processing recovery subtank 7RB, which are arranged on the front side along the main scanning direction S.

[0035] The first supply subtank 71A and first recovery subtank 71B, located on the far left side of the carriage 3, contain yellow ink. The first supply subtank 71A supplies yellow ink to the first upstream ink head 41A and the first downstream ink head 41B. Meanwhile, the first recovery subtank 71B recovers yellow ink from the first upstream ink head 41A and the first downstream ink head 41B. At this time, some of the yellow ink is ejected from the first upstream ink head 41A and the first downstream ink head 41B toward the workpiece W. Similarly, the second supply subtank 72A supplies magenta ink to the second upstream ink head 42A and the second downstream ink head 42B. Meanwhile, the second recovery subtank 72B recovers magenta ink from the second upstream ink head 42A and the second downstream ink head 42B. The remaining subtanks, from the third to the eighth subtank, have the same structure and function as those described above.

[0036] 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. 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.

[0037] As described above, the inkjet printer 1 according to this embodiment is an all-in-one printer in which three types of heads - the ink head 4, the pre-treatment liquid head 5, and the post-treatment liquid head 6 - are mounted on a single carriage 3. With this inkjet printer 1, for example, in the printing process of performing inkjet printing on fabric in digital textile printing, the process of ejecting the pre-treatment liquid and the process of ejecting the post-treatment liquid can be carried out in an integrated manner. This makes it possible to simplify the textile printing process and make the textile printing device more compact.

[0038] The inkjet printer 1 according to this embodiment uses a serial printing method to print on the workpiece W. Specifically, if the workpiece W is wide, it is not possible to print while continuously feeding the workpiece W. The serial printing method is a printing method that repeats reciprocating movement of a carriage 3 carrying ink heads 4 of each color in the main scanning direction S and intermittent feeding of the workpiece W in the transport direction F.

[0039] Specifically, the band-shaped image is printed while the carriage 3 moves in the forward direction, which is one of the main scanning directions S. During this main scanning in the forward direction, the feeding of the workpiece W is stopped. After the band-shaped image is printed, the workpiece W is sent out in the transport direction F by a predetermined pitch. At this time, the carriage 3 waits in the turn-back area 14 on the left end side. After the workpiece W is sent out, the carriage 3 turns back in the return direction, which is opposite to the forward direction, as the timing belt 16 moves in the reverse direction. The workpiece W is in a stopped state. Then, while moving in the return direction, the carriage 3 prints the next band-shaped image upstream of the previous band-shaped image. Similar operations are repeated thereafter.

[0040] Next, the pressure and ink supply to each ink head 4 according to this embodiment will be described with reference to Figures 4 to 6. Figure 4 is a schematic diagram showing multiple pressure transmission paths around the carriage 3 according to this embodiment. Figure 5 is a schematic diagram showing a supply sub-tank and a recovery sub-tank according to this embodiment. Figure 6 is a schematic diagram showing the flow of ink around the liquid ejection head according to this embodiment. In each figure, the lines connecting components indicate conduits (tubes) through which gas or liquid flows.

[0041] In this embodiment, pressure is applied via gas (air) to each of the first supply sub-tank 71A to post-treatment supply sub-tank 7RA and the first recovery sub-tank 71B to post-treatment recovery sub-tank 7RB mounted on the carriage 3 in Fig. 3. As a result, liquid (ink, pre-treatment liquid, post-treatment liquid) is supplied from each supply sub-tank to the ink head 4, pre-treatment liquid head 5, and post-treatment liquid head 6. First, the pressure supply path to each sub-tank 7 will be described with reference to Fig. 4.

[0042] The inkjet printer 1 includes a control unit 100, a compressor 50 (gas pressure source), a filter 51, a purge main regulator 52, a first main regulator 53, a second main regulator 54, an ink supply regulator 55, an ink recovery regulator 56, a treatment liquid supply regulator 57, and a treatment liquid recovery regulator 58. These devices or components are arranged on a device frame 10 ( FIG. 1 ) of the inkjet printer 1, outside the carriage 3.

[0043] The control unit 100 controls the overall operation of the inkjet printer 1, and electrically controls each of the components shown in FIG.

[0044] The compressor 50 generates the pressure to be supplied to each sub-tank 7, compressing the gas to increase the pressure and continuously sending it out. A known reciprocating or rotary compressor can be used as the compressor 50. As an example, the compressor pressure is set to 500 to 800 kPa.

[0045] The filter 51 removes foreign matter, dust, and the like contained in the gas discharged from the compressor 50. As an example, the opening diameter of the filter 51 is set to 5 μm. The gas that passes through the filter 51 flows into three flow paths: the first main pressure supply path P01, the second main pressure supply path P02, and the purge pressure supply path P03.

[0046] The purge main regulator 52 is disposed downstream of the filter 51 in the gas flow path and is a regulator for adjusting the pressure in the purge pressure supply path P03. Similarly, the first main regulator 53 is disposed downstream of the filter 51 in the gas flow path and is a regulator for adjusting the pressure in the first main pressure supply path P01. Similarly, the second main regulator 54 is disposed downstream of the filter 51 in the gas flow path and is a regulator for adjusting the pressure in the second main pressure supply path P02. Note that the purge main regulator 52, the first main regulator 53, and the second main regulator 54 are, for example, NPN-type regulators with open collector outputs. These regulators receive command signals from the control unit 100 and open their valves to adjust the pressure in each path to a value corresponding to the signal.

[0047] As shown in FIG. 4 , the first main pressure supply channel P01 is divided into eight flow paths downstream of the first main regulator 53, corresponding to the first to eighth supply sub-tanks 71A to 78A. Of these eight flow paths, FIG. 4 illustrates only the first supply-side pressure supply channel P11, the second supply-side pressure supply channel P21, and the eighth supply-side pressure supply channel P81, while omitting the other flow paths. The first supply-side pressure supply channel P11 extends from the first main pressure supply channel P01 (first main regulator 53) to the first supply sub-tank 71A. Similarly, the second supply-side pressure supply channel P21 extends from the first main pressure supply channel P01 to the second supply sub-tank 72A. The eighth supply-side pressure supply channel P81 extends from the first main pressure supply channel P01 to the eighth supply sub-tank 78A ( FIG. 3 ).

[0048] The ink supply regulators 55 are disposed in the respective supply-side pressure supply paths and function to adjust the pressure supplied to the respective ink supply sub-tanks. As an example, the ink supply regulators 55 are electropneumatic regulators. Also, in FIG. 4, a first ink supply regulator 551, a second ink supply regulator 552, and an eighth ink supply regulator 558 are illustrated corresponding to the first supply-side pressure supply path P11, the second supply-side pressure supply path P21, and the eighth supply-side pressure supply path P81, while the other ink supply regulators are not illustrated. These regulators receive command signals from the control unit 100 and open their valves to adjust the pressure of each flow path to a pressure corresponding to the signal. As an example, the target pressure applied to the supply sub-tank by each ink supply regulator 55 is set to 15 kPa.

[0049] Meanwhile, the second main pressure supply path P02 is divided into 12 flow paths downstream of the second main regulator 54, corresponding to the first recovery sub-tank 71B to the eighth recovery sub-tank 78B, the pre-treatment supply sub-tank 7FA, the pre-treatment recovery sub-tank 7FB, the post-treatment supply sub-tank 7RA, and the post-treatment recovery sub-tank 7RB. Of these 12 flow paths, Fig. 4 illustrates the first recovery-side pressure supply path P12, the second recovery-side pressure supply path P22, the eighth recovery-side pressure supply path P82, the pre-treatment liquid pressure supply path PFA, the pre-treatment liquid pressure recovery path PFB, the post-treatment liquid pressure supply path PRA, and the post-treatment liquid pressure recovery path PRB, while omitting the illustration of the other flow paths. The first recovery-side pressure supply path P12 is a flow path extending from the second main pressure supply path P02 (second main regulator 54) to the first recovery sub-tank 71B. Similarly, the second recovery-side pressure supply channel P22 is a flow path extending from the second main pressure supply channel P02 to the second recovery sub-tank 72B. The eighth recovery-side pressure supply channel P82 is a flow path extending from the second main pressure supply channel P02 to the eighth recovery sub-tank 78B. The pre-treatment liquid pressure supply channel PFA is a flow path extending from the second main pressure supply channel P02 (second main regulator 54) to the pre-treatment supply sub-tank 7FA, and the pre-treatment liquid pressure recovery channel PFB is a flow path extending from the second main pressure supply channel P02 to the pre-treatment recovery sub-tank 7FB. The post-treatment liquid pressure supply channel PRA is a flow path extending from the second main pressure supply channel P02 to the post-treatment supply sub-tank 7RA, and the post-treatment liquid pressure recovery channel PRB is a flow path extending from the second main pressure supply channel P02 to the post-treatment recovery sub-tank 7RB.

[0050] The ink recovery regulators 56 are disposed in the respective recovery pressure supply paths and function to adjust the pressure supplied to the respective ink recovery subtanks. As an example, the ink recovery regulators 56 are electropneumatic regulators. Also, in FIG. 4, a first ink recovery regulator 561, a second ink recovery regulator 562, and an eighth ink recovery regulator 568 are illustrated corresponding to the first recovery pressure supply path P12, the second recovery pressure supply path P22, and the eighth recovery pressure supply path P82, while the other ink recovery regulators are not illustrated. These regulators receive command signals from the control unit 100 and open their valves to adjust the pressure of each flow path to a pressure corresponding to the signal. As an example, the target pressure applied by each ink recovery regulator 56 to each ink recovery subtank is set to −20 kPa.

[0051] Similarly, the treatment liquid supply regulators 57 (pre-treatment liquid supply regulator 571, post-treatment liquid supply regulator 572) are disposed in the supply-side pressure supply paths of the respective treatment liquids, and the treatment liquid recovery regulators 58 (pre-treatment liquid recovery regulator 581, post-treatment liquid recovery regulator 582) are disposed in the recovery-side pressure supply paths of the respective treatment liquids. These regulators also have the same structure and function as the ink supply regulator 55 and the ink recovery regulator 56. Note that, as an example, the target pressure applied to each treatment liquid sub-tank by the treatment liquid supply regulator 57 and the treatment liquid recovery regulator 58 is set to −5 kPa.

[0052] Next, we will explain the pressure transmission paths above the carriage 3. As shown in Figure 4, the inkjet printer 1 further includes a first pressure measurement unit 1A, a second pressure measurement unit 1B, a third pressure measurement unit 1C, an ink supply purge valve 62, an ink supply measurement valve 63, an ink recovery purge valve 64, an ink recovery measurement valve 65, a treatment liquid purge valve 66, and a treatment liquid measurement valve 67, which are arranged above the carriage 3.

[0053] The first pressure measurement unit 1A has a first pressure sensor 611 and a first pressure measurement path M01. The second pressure measurement unit 1B has a second pressure sensor 612 and a second pressure measurement path M02. The third pressure measurement unit 1C has a third pressure sensor 613 and a third pressure measurement path M03.

[0054] The first pressure sensor 611 measures the pressure on the first pressure measurement path M01 and inputs a signal corresponding to the measurement result to the control unit 100. Similarly, the second pressure sensor 612 measures the pressure on the second pressure measurement path M02 and inputs a signal corresponding to the measurement result to the control unit 100. The third pressure sensor 613 measures the pressure on the third pressure measurement path M03 and inputs a signal corresponding to the measurement result to the control unit 100. The first pressure measurement path M01 can be connected to any of the supply paths from the first supply-side pressure supply path P11 to the eighth supply-side pressure supply path P81 depending on whether the ink supply measurement valve 63 is opened or closed. Similarly, the second pressure measurement path M02 can be connected to any of the supply paths from the first recovery-side pressure supply path P12 to the eighth recovery-side pressure supply path P82 depending on whether the ink recovery measurement valve 65 is opened or closed. The third pressure measurement path M03 can be connected to any one of the supply paths, namely, the pre-treatment liquid pressure supply path PFA, the pre-treatment liquid pressure recovery path PFB, the post-treatment liquid pressure supply path PRA, and the post-treatment liquid pressure recovery path PRB, depending on whether the treatment liquid measurement valve 67 is opened or closed.

[0055] The ink supply purge valves 62 are eight valves for connecting the purge pressure supply channel P03 to any of the first supply-side pressure supply channel P11 to the eighth supply-side pressure supply channel P81. As shown in FIG. 4 , the ink supply purge valves 62 include a first ink supply purge valve 621 arranged in the first supply-side pressure supply channel P11 and a second ink supply purge valve 622 arranged in the second supply-side pressure supply channel P21. Each of these valves is a known three-port solenoid valve, and in this embodiment, 20 three-port solenoid valves, together with the ink recovery purge valve 64 and the treatment liquid purge valve 66, are arranged in a single valve unit as a 20-port three-port solenoid valve.

[0056] As described above, the ink supply measurement valves 63 are eight valves for connecting the first pressure measurement path M01 to any of the first supply-side pressure supply channel P11 to the eighth supply-side pressure supply channel P81. As shown in Fig. 4, the ink supply measurement valves 63 include a first ink supply measurement valve 631 connected to the first supply-side pressure supply channel P11 and a second ink supply measurement valve 632 connected to the second supply-side pressure supply channel P21. Each of these valves is a known two-port solenoid valve, and in this embodiment, eight two-port solenoid valves are arranged in one valve unit as an eight-way two-port solenoid valve.

[0057] The ink recovery purge valve 64 is a set of eight valves for connecting the purge pressure supply channel P03 to any of the first recovery side pressure supply channel P12 to the eighth recovery side pressure supply channel P82. As shown in FIG. 4 , the ink recovery purge valve 64 includes a first ink recovery purge valve 641 disposed in the first recovery side pressure supply channel P12 and a second ink recovery purge valve 642 disposed in the second recovery side pressure supply channel P22. Each of these valves is a known three-port solenoid valve. A vacuum ejector (not shown) is disposed between the first ink recovery purge valve 641 and the first ink recovery regulator 561. The same applies to the other recovery valves and recovery regulators.

[0058] As described above, the ink recovery measurement valve 65 is eight valves for connecting the second pressure measurement path M02 to any of the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82. As shown in Fig. 4, the ink recovery measurement valve 65 includes a first ink recovery measurement valve 651 connected to the first recovery side pressure supply path P12 and a second ink recovery measurement valve 652 connected to the second recovery side pressure supply path P22. Each of these valves is a known two-port solenoid valve, and in this embodiment, eight two-port solenoid valves are arranged in one valve unit as an eight-way two-port solenoid valve.

[0059] The processing liquid purge valve 66 is a set of four valves for connecting the purge pressure supply channel P03 to any one of the pre-processing liquid pressure supply channel PFA, the pre-processing liquid pressure recovery channel PFB, the post-processing liquid pressure supply channel PRA, and the post-processing liquid pressure recovery channel PRB. As shown in Fig. 4, the processing liquid purge valve 66 includes a first processing liquid purge valve 661 connected to the pre-processing liquid pressure supply channel PFA and a second processing liquid purge valve 662 connected to the pre-processing liquid pressure recovery channel PFB. As described above, each of these valves is a known three-port solenoid valve.

[0060] The treatment liquid measurement valves 67 are four valves for connecting the third pressure measurement path M03 to any one of the treatment liquid pressure supply path PFA, the treatment liquid pressure recovery path PFB, the post-treatment liquid pressure supply path PRA, and the post-treatment liquid pressure recovery path PRB. As shown in FIG. 4 , the treatment liquid measurement valves 67 include a first treatment liquid measurement valve 671 connected to the treatment liquid pressure supply path PFA and a second treatment liquid measurement valve 672 connected to the treatment liquid pressure recovery path PFB. Each of these valves is a known two-port solenoid valve, and in this embodiment, four two-port solenoid valves are arranged in one valve unit as a quadruple two-port solenoid valve.

[0061] Next, the structure of the subtank 7 will be further described with reference to Figure 5. Note that the following description will be given using the first supply subtank 71A and the first recovery subtank 71B, which supply and recover yellow ink, as examples, but the structure of the other subtanks 7 is similar.

[0062] The first supply sub-tank 71A has a box-like structure, and when yellow ink is stored therein, a supply tank gas area SA and a supply tank ink area SB are formed. The supply tank gas area SA is the space above the liquid surface of the yellow ink in the first supply sub-tank 71A, and the supply tank ink area SB is the area formed by the yellow ink. The supply tank gas area SA is connected to the first supply-side pressure supply path P11 described above. The supply tank ink area SB is also connected to the ink supply path QA (first ink path Q1, second ink path Q2), ink circulation path Q3, and ink refill path Q4, which will be described later.

[0063] The first supply sub-tank 71A has a capacitance sensor 71A1 that can detect the liquid level (ink amount) of yellow ink in the first supply sub-tank 71A.

[0064] Similarly, the first recovery sub-tank 71B has a box-like structure, and when yellow ink is stored therein, a recovery tank gas region SC and a recovery tank ink region SD are formed. The recovery tank gas region SC is the space above the liquid surface of the yellow ink in the first recovery sub-tank 71B, and the recovery tank ink region SD is the region formed by the yellow ink. The recovery tank gas region SC is connected to the first recovery side pressure supply path P12 described above. The recovery tank ink region SD is also connected to the ink recovery path QB (first ink path Q1, second ink path Q2) and the ink circulation path Q3, which will be described later.

[0065] The first collection sub-tank 71B has a capacitance sensor 71B1 that can detect the liquid level (ink amount) of yellow ink in the first collection sub-tank 71B.

[0066] Next, the supply and recovery paths of yellow ink to the first upstream ink head 41A and the first downstream ink head 41B will be described with reference to Figure 6. Note that a structure similar to that shown in Figure 6 is also provided for the ink heads of other colors. The inkjet printer 1 further includes filters 81, 82, 83, and 84, a circulation pump 85, a check valve 86, and a degasser 87, which are arranged on the carriage 3. The inkjet printer 1 also includes a main tank 90, a capacitance sensor 91, a main tank valve 92, and a main supply pump 93, which are arranged on the device frame 10 (Figure 1) outside the carriage 3.

[0067] Yellow ink flowing from the first supply subtank 71A into the ink supply path QA is divided into a first ink path Q1 via the first upstream ink head 41A and a second ink path Q2 via the first downstream ink head 41B. A filter 81 is located upstream of the first upstream ink head 41A, and a filter 82 is located upstream of the first downstream ink head 41B. A filter 83 is located downstream of the first upstream ink head 41A, and a filter 84 is located downstream of the first downstream ink head 41B. These filters function to remove foreign matter, dust, etc. from the ink. After a portion of the yellow ink is ejected onto the workpiece W from the first upstream ink head 41A and the first downstream ink head 41B, the remaining ink is collected through the ink collection path QB into the first collection subtank 71B.

[0068] On the other hand, when the control unit 100 determines from the output of the capacitance sensor 71A1 (FIG. 5) that there is little ink in the first supply subtank 71A, the circulation pump 85 operates in response to a command signal input from the control unit 100. As a result, some of the yellow ink in the first recovery subtank 71B is supplied to the first supply subtank 71A through the ink circulation path Q3. The check valve 86 makes it difficult for ink to backflow from the first supply subtank 71A toward the first recovery subtank 71B within the ink circulation path Q3. The degasser 87 also removes air bubbles and other contaminants from the ink flowing into the first supply subtank 71A.

[0069] Furthermore, when the control unit 100 determines, based on the detection results of the capacitance sensors 71A1, 71B1, that the amount of yellow ink in both the first supply subtank 71A and the first recovery subtank 71B has fallen below a preset threshold, the control unit 100 operates the main supply pump 93 to replenish yellow ink from the main tank 90 to the first supply subtank 71A through the ink refill path Q4. The main tank valve 92 opens to adjust the maximum replenishment amount (replenishment speed) for the first supply subtank 71A. Furthermore, when the capacitance sensor 91 detects that the remaining amount of yellow ink in the main tank 90 is low, the control unit 100 displays an ink refill message on the display unit (not shown) of the inkjet printer 1.

[0070] <Pressure Transmission Path During Printing> Figure 7 is a schematic diagram corresponding to Figure 4 and showing the state during printing (when ejecting liquid). Below, we will explain the subtanks 7 (first supply subtank 71A, first recovery subtank 71B) corresponding to yellow ink and the subtanks 7 (second supply subtank 72A, second recovery subtank 72B) corresponding to magenta ink in Figure 7. The same applies to the other colors.

[0071] 7 , when the inkjet printer 1 ejects ink onto a workpiece W to perform printing, the first ink supply purge valve 621 connects the first ink supply regulator 551 to the first supply sub-tank 71A, and the second ink supply purge valve 622 connects the second ink supply regulator 552 to the second supply sub-tank 72A. The first ink recovery purge valve 641 connects the first ink recovery regulator 561 to the first recovery sub-tank 71B, and the second ink recovery purge valve 642 connects the second ink recovery regulator 562 to the second recovery sub-tank 72B. In other words, the first supply-side pressure supply channel P11, the first recovery-side pressure supply channel P12, the second supply-side pressure supply channel P21, and the second recovery-side pressure supply channel P22 are blocked from the purge pressure supply channel P03.

[0072] As a result, the adjusted pressure of the first ink supply regulator 551 is applied to the yellow ink in the supply tank ink region SB via the supply tank gas region SA of the first supply sub-tank 71A. Similarly, the adjusted pressure of the first ink recovery regulator 561 is applied to the yellow ink in the recovery tank ink region SD via the recovery tank gas region SC of the first recovery sub-tank 71B. Therefore, as shown in Figures 5 and 6, the ink inside the first upstream ink head 41A and the first downstream ink head 41B is adjusted to a predetermined pressure via the ink supply path QA and the ink recovery path QB, reducing the possibility of ink unintentionally spraying from the nozzles of the ink heads.

[0073] Furthermore, in this embodiment, during printing, the control unit 100 sequentially opens the ink supply measurement valve 63 and the ink recovery measurement valve 65. Specifically, as shown in FIG. 7 , the first ink supply measurement valve 631 connects the first supply-side pressure supply path P11 to the first pressure measurement path M01, while the other valves of the ink supply measurement valve 63, including the second ink supply measurement valve 632, are closed. In this state, the first pressure sensor 611 measures the pressure in the first pressure measurement path M01, making it possible to measure the pressure applied to the supply tank ink region SB through the supply tank gas region SA of the first supply subtank 71A. Similarly, the first ink recovery measurement valve 651 connects the first recovery-side pressure supply path P12 to the second pressure measurement path M02, while the other valves of the ink recovery measurement valve 65, including the second ink recovery measurement valve 652, are closed. In this state, the second pressure sensor 612 measures the pressure in the second pressure measurement path M02, making it possible to measure the pressure applied to the recovery tank ink area SD through the recovery tank gas area SC of the first recovery sub-tank 71B.

[0074] Next, the control unit 100 controls each valve to close the first ink supply measurement valve 631 and open the second ink supply measurement valve 632, and also to close the first ink recovery measurement valve 651 and open the second ink recovery measurement valve 652. In this state, the first pressure sensor 611 measures the pressure in the first pressure measurement path M01, making it possible to measure the pressure applied to the supply tank ink region SB through the supply tank gas region SA of the second supply subtank 72A. Furthermore, the second pressure sensor 612 measures the pressure in the second pressure measurement path M02, making it possible to measure the pressure applied to the recovery tank ink region SD through the recovery tank gas region SC of the second recovery subtank 72B. Thereafter, it becomes possible to measure the pressure applied to the ink in the supply subtank and recovery subtank of each color in turn.

[0075] The control unit 100 adjusts the opening of each ink supply regulator 55 and each ink recovery regulator 56 based on PID control from the pressure measured as described above, thereby adjusting the pressure applied to each sub-tank, and as a result, can adjust the pressure applied to the ink in the ink head 4. The same applies to the pressure measurement and pressure adjustment of each treatment liquid sub-tank and each treatment liquid head using the third pressure sensor 613 and treatment liquid measurement valve 67.

[0076] <Pressure Transmission Path During Purge Operation> Figure 8 is a schematic diagram corresponding to Figure 4 and showing the state during the purge operation. The purge operation applies a higher pressure to the ink head 4 than during printing, causing ink to be ejected from the nozzles of the ink head 4 in order to release or prevent ink clogging in the ink head 4. Referring to Figure 8, when applying purge pressure to the first upstream ink head 41A and the first downstream ink head 41B, the control unit 100 opens the first ink supply purge valve 621 of the ink supply purge valve 62 to connect the first supply-side pressure supply channel P11 and the purge pressure supply channel P03. This allows the purge pressure regulated by the purge main regulator 52 to act on the first supply-side pressure supply channel P11. At this time, the first ink supply measurement valve 631 is closed to reduce the possibility of the purge pressure being applied to the first pressure sensor 611 and damaging it.

[0077] On the other hand, in the first recovery side pressure supply path P12 that communicates with the first recovery sub-tank 71B, the first ink recovery measurement valve 651 is similarly closed to reduce the possibility of purge pressure being applied to the second pressure sensor 612. In addition, the first ink recovery purge valve 641 connects the first recovery side pressure supply path P12 with the first ink recovery regulator 561.

[0078] In this case, a two-port solenoid valve (not shown) may be disposed upstream of the first recovery sub-tank 71B (between the first recovery sub-tank 71B and the first ink recovery measurement valve 651 in FIG. 8), and the two-port solenoid valve may be closed when purge pressure is applied to each ink head through the first supply-side pressure supply path P11. Alternatively, the above-mentioned two-port solenoid valve may be disposed downstream of the first recovery sub-tank 71B (ink recovery path QB in FIG. 6), and similar switching may be performed. As a result, purge pressure can be applied to each ink head from the supply side while the recovery side path is closed.

[0079] In another embodiment, the first ink recovery purge valve 641 may be opened to connect the first recovery pressure supply channel P12 and the purge pressure supply channel P03. In this case, the purge pressure also acts on the first upstream ink head 41A and the first downstream ink head 41B through the first recovery sub-tank 71B, so that the purge pressure can be applied to the ink heads from both the supply side and the recovery side.

[0080] As shown in FIG. 4 , the inkjet printer 1 according to this embodiment includes a pressure measurement device 1S. The pressure measurement device 1S can measure the pressure of multiple pressure transmission paths that apply pressure to an object via gas (air). In this embodiment, the object is a liquid, particularly ink, that comes into contact with the gas ejected from the end of the pressure transmission path. The pressure measurement device 1S includes a pressure measurement unit and a switching unit. Focusing on the first supply-side pressure supply path P11 to the eighth supply-side pressure supply path P81 (multiple pressure transmission paths) in FIG. 4 , the pressure measurement unit includes a first pressure measurement path M01 (measurement path) that has an internal space capable of receiving the gas, and a first pressure sensor 611 (pressure sensor) that detects the pressure in the internal space. The switching unit also includes an ink supply measurement valve 63. The ink supply measurement valve 63 selectively switches the connection destination of the first pressure measurement path M01 from the first supply-side pressure supply path P11 to the eighth supply-side pressure supply path P81. Note that the second pressure sensor 612, the second pressure measurement path M02, and the ink recovery measurement valve 65, as well as the third pressure sensor 613, the third pressure measurement path M03, and the treatment liquid measurement valve 67 in Figure 4 similarly constitute the pressure measurement device 1S.

[0081] With this pressure measurement device 1S, it is possible to measure the pressure in the pressure transmission paths using a number of pressure sensors that is fewer than the number of pressure transmission paths. Furthermore, a predetermined pressure can be easily and stably applied to the ink in the subtank 7. Furthermore, because pressure is transmitted through each path via gas, even if the liquids contained in each subtank 7 (ink, pre-treatment liquid, post-treatment liquid) are different, the possibility of these liquids mixing with each other can be reduced.

[0082] Furthermore, in this embodiment, the pressure measurement device 1S is mounted on an inkjet printer 1. The inkjet printer 1 has an ink head 4 (liquid ejection unit) that ejects ink onto a workpiece W (recording material). Each of the pressure supply paths, represented by the first supply-side pressure supply path P11 and the first recovery-side pressure supply path P12, applies pressure to the liquid supplied to the ink head 4, the pre-treatment liquid head 5, and the post-treatment liquid head 6, or the liquid recovered from these heads. This makes it possible to stably apply pressure to the ink in the ink head 4, and to efficiently measure that pressure.

[0083] Furthermore, in this embodiment, each pressure transmission path represented by the first supply-side pressure supply path P11 and the first recovery-side pressure supply path P12 receives pressure via air from a compressor 50 (gas pressure source) disposed outside the carriage 3. In other words, the first supply-side pressure supply path P11 and the first recovery-side pressure supply path P12 receive pressure from the compressor 50 at the first main regulator 53. In this way, because the compressor 50 is disposed outside the carriage 3, pressure fluctuations due to movement of the carriage 3 are unlikely to occur, and pressure can be applied stably to each head and each sub-tank 7.

[0084] Note that instead of the compressor 50, the first main regulator 53 may receive pressure from a pump (gas pressure source) (not shown) mounted on the carriage 3. In this case, the pressure transmission paths for each head can be concentrated and arranged inside the carriage 3.

[0085] 3 constitute a liquid ejection unit of the present disclosure. The first upstream ink head 41A, the first downstream ink head 41B, the first supply sub-tank 71A, and the first recovery sub-tank 71B eject yellow ink onto the workpiece W. The first supply sub-tank 71A (supply sub-tank) includes a supply tank ink region SB (first liquid region) and a supply tank gas region SA (first gas region) therein, and supplies yellow ink to the first upstream ink head 41A and the first downstream ink head 41B. The first recovery sub-tank 71B (recovery sub-tank) includes a recovery tank ink region SD (second liquid region) and a recovery tank gas region SC (second gas region) therein, and recovers yellow ink from the first upstream ink head 41A and the first downstream ink head 41B. Ink heads, supply sub-tanks, and recovery sub-tanks corresponding to the other colors similarly constitute a liquid ejection unit of the present disclosure.

[0086] Each supply pressure transmission path, represented by the first supply-side pressure supply path P11, is connected to the supply tank gas area SA of each supply sub-tank. Each recovery pressure transmission path, represented by the first recovery-side pressure supply path P12, is connected to the recovery tank gas area SC of each recovery sub-tank. During printing with the inkjet printer 1, the ink supply measurement valve 63 (first switching unit) selectively switches the connection destination of the internal space (first internal space) of the first pressure measurement path M01 of the first pressure measurement unit 1A from the first supply-side pressure supply path P11 to one of the eighth supply-side pressure supply paths P81 (plurality of supply pressure transmission paths), and the first pressure sensor 611 of the first pressure measurement unit 1A measures the pressure of the first internal space while the first internal space is connected to the supply tank gas area SA of one of the supply sub-tanks of the plurality of liquid ejection units. Meanwhile, the ink recovery measurement valve 65 (second switching unit) selectively switches the connection destination of the internal space (second internal space) of the second pressure measurement unit 1B from the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82 (plurality of recovery pressure transmission paths), and the second pressure sensor 612 of the second pressure measurement unit 1B measures the pressure of the second internal space while the second internal space is connected to the recovery tank gas region SC of one of the plurality of liquid ejection units.

[0087] With this configuration, a first pressure measurement unit 1A is arranged for multiple supply sub-tanks, and a second pressure measurement unit 1B is arranged for multiple recovery sub-tanks. As described above, the first supply-side pressure supply path P11 to the eighth supply-side pressure supply path P81 are set to approximately the same pressure, and the first recovery-side pressure supply path P12 to the eighth recovery-side pressure supply path P82 are also set to approximately the same pressure. However, a predetermined pressure difference exists between the supply side and the recovery side to control ink ejection. With the above configuration, no large pressure difference occurs at the connection points of the first pressure measurement path M01 and the second pressure measurement path M02, and pressure fluctuations resulting from this pressure difference do not interfere with the flow of ink.

[0088] In particular, in this embodiment, a dedicated ink supply measurement valve 63 is provided on the ink supply side as a switching unit, and a dedicated ink recovery measurement valve 65 is provided on the ink recovery side. Therefore, compared to when a single switching unit is used to switch between the supply side path and the recovery side path, the pressure transmission path does not become complicated, and pressure transmission and measurement in each path can be performed stably. Note that in other embodiments, a single switching unit may be used to switch between the supply side path and the recovery side path, as described above.

[0089] In this embodiment, as shown in Figure 4, the first pressure measurement unit 1A is provided on the ink supply side and the second pressure measurement unit 1B is provided on the ink recovery side. However, if ink ejection can be sufficiently controlled by measuring and adjusting the pressure supplied to each supply subtank, the pressure measurement device 1S may have only the first pressure measurement unit 1A and not the second pressure measurement unit 1B. Similarly, if ink ejection can be sufficiently controlled by measuring and adjusting the pressure supplied to each recovery subtank, the pressure measurement device 1S may have only the second pressure measurement unit 1B and not the first pressure measurement unit 1A. In this case, the pressure in each pressure transmission path can be stably measured while reducing the number of pressure sensors and the associated costs.

[0090] 4 function as the pressure receiving section of the present disclosure. The ink supply measurement valve 63 switches the connection of the internal space of the first pressure measurement path M01 of the first pressure measurement unit 1A. For example, when measuring the pressure of the first supply-side pressure supply path P11, the first ink supply purge valve 621 opens the first supply-side pressure supply path P11 to connect the supply tank gas region SA of the first supply sub-tank 71A to the first main regulator 53. Similarly, the ink recovery measurement valve 65 switches the connection of the internal space of the second pressure measurement path M02 of the second pressure measurement unit 1B. For example, when measuring the pressure of the first recovery-side pressure supply path P12, the first ink recovery purge valve 641 opens the first recovery-side pressure supply path P12 to connect the recovery tank gas region SC of the first recovery sub-tank 71B to the second main regulator 54. In this state, the first pressure sensor 611 and the second pressure sensor 612 measure the pressure in the first pressure measurement path M01 and the second pressure measurement path M02, and if necessary, adjust the opening of the first ink supply regulator 551 and the first ink recovery regulator 561 to adjust the pressure acting on the first supply sub-tank 71A and the first recovery sub-tank 71B.

[0091] With this configuration, the first pressure measurement path M01 is connected to both the supply tank gas area SA of the first supply sub-tank 71A and the first ink supply regulator 551, so that the pressure of the entire ink supply system can be measured comprehensively, and the pressure acting on the ink in the first supply sub-tank 71A can be accurately determined. The same applies to the second pressure measurement path M02.

[0092] The first pressure sensor 611 and the second pressure sensor 612 may simultaneously measure the pressures of the first supply sub-tank 71A and the first recovery sub-tank 71B. That is, the first ink supply measurement valve 631 of the ink supply measurement valve 63 connects the first pressure measurement path M01 (first internal space) of the first pressure measurement unit 1A to the first supply side pressure supply path P11, so that the first internal space is in communication with the supply tank gas area SA of the first supply sub-tank 71A, and the first pressure sensor 611 of the first pressure measurement unit 1A measures the pressure of the first internal space, and the first ink recovery measurement valve 651 of the ink recovery measurement valve 65 connects the second pressure measurement path M02 (second internal space) of the second pressure measurement unit 1B to the first recovery side pressure supply path P12, so that the second internal space is in communication with the recovery tank gas area SC of the first recovery sub-tank 71B, and the second pressure sensor 612 of the second pressure measurement unit 1B measures the pressure of the second internal space.

[0093] According to this configuration, the pressure on the supply side and the pressure on the recovery side are measured simultaneously for the same liquid discharge portion, so that it is possible to improve the effective measurement accuracy.

[0094] 4, it is desirable that the volume of the first pressure measurement path M01 of the first pressure measurement unit 1A be set to be equal to or less than the volume of the first supply sub-tank 71A, and even more desirably, equal to or less than 0.5 times the volume of the first supply sub-tank 71A. With this configuration, the first pressure sensor 611 measures the pressure on the first pressure measurement path M01, thereby enabling the pressure of the first supply sub-tank 71A to be measured with high accuracy.

[0095] It is more desirable that the volume of the first pressure measurement path M01 of the first pressure measurement unit 1A be set to be equal to or less than the volume of the supply tank gas area SA of the first supply sub-tank 71A, and even more desirably, equal to or less than 0.5 times the volume of the supply tank gas area SA. With this configuration, the first pressure sensor 611 measures the pressure on the first pressure measurement path M01, thereby enabling the pressure of the first supply sub-tank 71A to be measured with even greater accuracy.

[0096] 4, the volume of the second pressure measurement path M02 of the second pressure measurement unit 1B is preferably set to be equal to or less than the volume of the first collection sub-tank 71B, and even more preferably equal to or less than 0.5 times the volume of the first collection sub-tank 71B. With this configuration, the second pressure sensor 612 measures the pressure on the second pressure measurement path M02, thereby enabling the pressure of the first collection sub-tank 71B to be measured with high accuracy.

[0097] Furthermore, it is more desirable that the volume of the second pressure measurement path M02 of the second pressure measurement unit 1B be set to be equal to or less than the volume of the recovery tank gas region SC of the first recovery sub-tank 71B, and even more desirably, equal to or less than 0.5 times the volume of the recovery tank gas region SC. With this configuration, the second pressure sensor 612 measures the pressure of the second pressure measurement path M02, thereby enabling the pressure of the first recovery sub-tank 71B to be measured with even greater accuracy.

[0098] In particular, when the volume relationship as described above is present, when the pressure measurement path is switched by the ink supply measurement valve 63 or the ink recovery measurement valve 65, pressure fluctuations in each head or subtank 7 are less likely to occur due to the pressure difference between the subtank 7 that is connected to the first pressure measurement path M01 or the second pressure measurement path M02 immediately before the switching and the subtank 7 that is connected to the first pressure measurement path M01 or the second pressure measurement path M02 immediately after the switching.

[0099] 2 and 4, in this embodiment, the pressures of the pressure transmission paths connecting the ink head 4 (ink ejection portion), the pre-treatment liquid head 5 (pre-treatment liquid ejection portion), and the post-treatment liquid head 6 (post-treatment liquid ejection portion) can be measured with high accuracy by the first pressure measurement portion 1A, the second pressure measurement portion 1B, and the third pressure measurement portion 1C, respectively. This makes it possible to stably control the amounts of the pre-treatment liquid, ink, and post-treatment liquid that land in sequence on the workpiece W.

[0100] A filter may be disposed in the first supply-side pressure supply path P11 between the supply tank gas region SA of the first supply sub-tank 71A and the first pressure measurement path M01 of the first pressure measurement unit 1A. This reduces the possibility of the ink and the pretreatment liquid mixing. If the mist-like ink and the pretreatment liquid enter and mix with each other within the first pressure measurement unit 1A, the pretreatment liquid may thicken some of the ink components, or they may aggregate and adhere or solidify within the first pressure measurement unit 1A. This phenomenon may reduce measurement accuracy or cause measurement malfunctions. By disposing a filter, mist larger than the filter opening can be prevented from entering, and mist smaller than the filter opening can be prevented from entering because it strikes areas other than the filter opening. For the same reason, a filter may be disposed in the first recovery-side pressure supply path P12 between the recovery tank gas region SC of the first recovery sub-tank 71B and the second pressure measurement path M02 of the second pressure measurement unit 1B. The same applies to the other sub-tanks 7.

[0101] 4, the first pressure measurement unit 1A exclusively measures the pressure in the pressure transmission path of the supply system, and the second pressure measurement unit 1B exclusively measures the pressure in the pressure transmission path of the recovery system. However, in other embodiments, a switching unit (valve, not shown) may selectively switch the connection destination of the first pressure measurement path M01 of the first pressure measurement unit 1A between the first supply-side pressure supply path P11 and the first recovery-side pressure supply path P12, so that the first pressure measurement path M01 is connected to the supply tank gas region SA of the first supply sub-tank 71A or the recovery tank gas region SC of the first recovery sub-tank 71B, and the first pressure sensor 611 may measure the pressure in the first pressure measurement path M01. In this case, the single first pressure sensor 611 can sequentially measure the pressures in the first supply sub-tank 71A and the first recovery sub-tank 71B corresponding to the same ink color. It is desirable that the first pressure sensor 611 be designed to have high pressure resistance so that it can handle the pressure difference between the first supply sub-tank 71A and the first recovery sub-tank 71B. In this embodiment, the third pressure sensor 613 in Fig. 4 can measure the pressures of the supply sub-tanks and recovery sub-tanks for the pre-treatment liquid and post-treatment liquid in sequence. This is because the pressure setting values ​​of these sub-tanks are similar.

[0102] Furthermore, the inkjet printer 1 according to this embodiment has the following configuration. The inkjet printer 1 includes a carriage 3 and a workpiece transport unit 20. As shown in FIG. 4 , the inkjet printer 1 also includes a first main regulator 53 (first pressure receiving portion) and a second main regulator 54 (second pressure receiving portion), which are arranged on the outside of the carriage 3. The carriage 3 includes a first supply sub-tank 71A and a first recovery sub-tank 71B. A portion of the ink sent from the supply tank ink region SB of the first supply sub-tank 71A to the first upstream ink head 41A and the first downstream ink head 41B is ejected from each head, and the other portion is sent to the recovery tank ink region SD of the first recovery sub-tank 71B. The first main regulator 53 is connected to the supply tank gas area SA of the first supply sub-tank 71A via air (gas), and the pressure received by the first main regulator 53 from the compressor 50 applies pressure to the supply tank ink area SB via the supply tank gas area SA. Similarly, the second main regulator 54 is connected to the recovery tank gas area SC of the first recovery sub-tank 71B via air, and the pressure received by the second main regulator 54 applies pressure to the recovery tank ink area SD via the recovery tank gas area SC.

[0103] With this configuration, the first ink supply regulator 551 can apply a desired pressure to the supply tank ink region SB (ink layer) of the first supply subtank 71A. Similarly, the second ink supply regulator 552 can apply a desired pressure to the recovery tank ink region SD of the first recovery subtank 71B. Ink can be supplied to and recovered from each ink head using the difference in pressure between the supply tank ink region SB (ink layer) in the first supply subtank 71A and the recovery tank ink region SD (ink layer) in the first recovery subtank 71B.

[0104] As described above, since the carriage 3 moves back and forth during printing, if pressure is applied from outside the carriage, the medium that mediates the pressure from outside the carriage will apply extra pressure due to acceleration during acceleration and deceleration, making the pressure more likely to fluctuate. However, in this embodiment, pressure is applied via gas as the medium, so the pressure fluctuations caused by the acceleration described above are reduced.

[0105] In the above configuration, the pressure receiving portion exemplified by the first main regulator 53 and the second main regulator 54 may be a single portion. Also, as shown in FIGS. 5 and 6 , the ink is circulated between each ink head, the supply sub-tank, and the recovery sub-tank, but a configuration without circulation is also possible. The sub-tank may be provided only for supply. Furthermore, the configuration for transmitting pressure from outside the carriage 3 via gas may be on at least one of the supply side and the recovery side. On the supply side or the recovery side to which the above configuration is not applied, pressure fluctuations may be tolerated, or a pressure receiving portion may be provided on the carriage 3.

[0106] Furthermore, in this embodiment, a first ink supply regulator 551 (first adjustment unit) that adjusts the amount of gas passing through is disposed in the first supply-side pressure supply path P11 that connects the first main regulator 53 and the supply tank gas area SA of the first supply sub-tank 71A and transmits pressure using air. The first pressure sensor 611 measures the pressure in the portion of the first supply-side pressure supply path P11 that is closer to the first supply sub-tank 71A than the first ink supply regulator 551.

[0107] With this configuration, the pressure acting on the ink in the supply tank ink region SB of the first supply sub-tank 71A can be controlled via the supply tank gas region SA of the first supply sub-tank 71A by adjusting the first ink supply regulator 551 based on the measurement results of the first pressure sensor 611. In this case, the first ink supply regulator 551 may be adjusted taking into account the measurement results of the second pressure sensor 612 in addition to the measurement results of the first pressure sensor 611.

[0108] Similarly, in this embodiment, a first ink recovery regulator 561 (second adjustment unit) that adjusts the amount of gas passing through is disposed in the first recovery side pressure supply path P12 that connects the second main regulator 54 and the recovery tank gas region SC of the first recovery sub-tank 71B and transmits pressure using air. The second pressure sensor 612 measures the pressure in the portion of the first recovery side pressure supply path P12 that is closer to the first recovery sub-tank 71B than the first ink recovery regulator 561.

[0109] With this configuration, it is possible to control the pressure acting on the ink in the recovery tank ink region SD of the first recovery sub-tank 71B via the recovery tank gas region SC by adjusting the first ink recovery regulator 561 based on the measurement results of the second pressure sensor 612. In this case, the first ink recovery regulator 561 may also be adjusted taking into account the measurement results of the first pressure sensor 611 in addition to the measurement results of the second pressure sensor 612. The same applies to inks of other colors.

[0110] 4, the adjustment units represented by the first ink supply regulator 551 and the first ink recovery regulator 561 are not limited to those arranged outside the carriage 3, but may be mounted on the carriage 3. When these adjustment units are mounted on the carriage 3, the number of air pressure tubes for adjusting pressure from the main body can be reduced to one, regardless of the number of colors. On the other hand, when these adjustment units are arranged outside the carriage 3, the weight and compactness of the carriage 3 can be reduced.

[0111] Furthermore, the present disclosure is not limited to the above-described embodiments, and may take the following forms.

[0112] (1) The ink heads 4 are not limited to being arranged in two rows on the carriage 3. The ink heads 4 may be arranged in one row, or in three or more rows. Furthermore, the inkjet printer 1 is not limited to being configured to be capable of ejecting ink of multiple colors onto the workpiece W, and may be configured to eject ink of a single color.

[0113] (2) In the above embodiment, the inkjet printer 1 may not have the pre-treatment liquid head 5 that ejects the pre-treatment liquid, the post-treatment liquid head 6 that ejects the post-treatment liquid, or any of their associated components. Furthermore, at least one of the pre-treatment liquid and the post-treatment liquid may not have a collection tank.

[0114] (3) The multiple configurations disclosed in the above embodiments can be combined with each other to form a single disclosure.

[0115] REFERENCE SIGNS LIST 1 Inkjet printer (recording device) 10 Device frame 100 Control unit 1A First pressure measurement unit (pressure measurement unit) 1B Second pressure measurement unit (pressure measurement unit) 1C Third pressure measurement unit (pressure measurement unit) 1S Pressure measurement device 20 Work transport unit (transport unit) 3 Carriage 4 Ink head (ink ejection unit) 41A First upstream ink head 41B First downstream ink head 5 Pre-treatment liquid head (pre-treatment liquid ejection unit) 50 Compressor (gas pressure source) 51 Filter 52 Purge main regulator 53 First main regulator (pressure receiving unit) 54 Second main regulator (pressure receiving unit) 55 Ink supply regulator 551 First ink supply regulator 552 Second ink supply regulator 56 Ink recovery regulator 561 First ink recovery regulator 562 Second ink recovery regulator 6 Post-treatment liquid head (post-treatment liquid ejection unit) 611 First pressure sensor 612 Second pressure sensor 613 Third pressure sensor 62 Ink supply purge valve 621 First ink supply purge valve 622 Second ink supply purge valve 63 Ink supply measurement valve (switching unit, first switching unit) 631 First ink supply measurement valve 632 Second ink supply measurement valve 64 Ink recovery purge valve 641 First ink recovery purge valve 642 Second ink recovery purge valve 65 Ink recovery measurement valve (switching unit, second switching unit) 651 First ink recovery measurement valve 652 Second ink recovery measurement valve 7 Subtank 71A First supply subtank (supply subtank) 71A1, 71B1 Capacitance sensor 71B First recovery subtank (recovery subtank) 72A Second supply subtank (supply subtank) 72B Second recovery subtank (recovery subtank) M01 First pressure measurement path (internal space, first internal space) M02 Second pressure measurement path (internal space, second internal space) M03 Third pressure measurement path P01 First main pressure supply path P02 Second main pressure supply pathP03 Purge pressure supply path P11 First supply side pressure supply path (pressure transmission path, supply pressure transmission path) P12 First recovery side pressure supply path (pressure transmission path, recovery pressure transmission path) P21 Second supply side pressure supply path (pressure transmission path, supply pressure transmission path) P22 Second recovery side pressure supply path (pressure transmission path, recovery pressure transmission path) SA Supply tank gas area SB Supply tank ink area SC Recovery tank gas area SD Recovery tank ink area W Work

Claims

1. A device comprising: a plurality of pressure transmission paths, each of which contains a gas for applying pressure to a liquid, and each of which can adjust the magnitude of the pressure of the gas; a pressure measuring device for measuring the magnitude of the pressure of the gas present in each of the plurality of pressure transmission paths; at least one liquid ejection unit that ejects liquid onto a recording material; Equipped with The pressure measuring device is At least one pressure measurement unit including a measurement path having an internal space capable of receiving the gas and a pressure sensor that detects the pressure of the gas present in the internal space; at least one switching unit capable of selectively switching the connection destination of the measurement path from among the plurality of pressure transmission paths in a state in which the gas is being supplied to the liquid; Equipped with The gas supplied from each of the plurality of pressure transmission paths applies the pressure to the liquid supplied to the at least one liquid ejection unit or the liquid recovered from the at least one liquid ejection unit.

2. 2. The recording device according to claim 1, a carriage that supports the at least one liquid ejection unit and moves back and forth in a main scanning direction; The plurality of pressure transmission paths receive pressure via the gas from a gas pressure source disposed outside the carriage.

3. A plurality of pressure transmission paths that apply pressure to an object via gas; a pressure measuring device for measuring pressures in the plurality of pressure transmission paths; at least one liquid ejection unit that ejects liquid onto a recording material; a carriage supporting the at least one liquid ejection unit and reciprocating in a main scanning direction; The pressure measuring device is At least one pressure measurement unit including a measurement path having an internal space capable of receiving the gas and a pressure sensor that detects the pressure in the internal space; at least one switching unit capable of selectively switching the connection destination of the measurement path from among the plurality of pressure transmission paths; Equipped with the target object is a liquid that comes into contact with the gas discharged from the terminal end of the pressure transmission path, each of the plurality of pressure transmission paths applies the pressure to the liquid supplied to the at least one liquid ejection unit or the liquid recovered from the at least one liquid ejection unit; The plurality of pressure transmission paths receive pressure via the gas from a gas pressure source mounted on the carriage.

4. 4. The recording device according to claim 1, the at least one liquid ejection unit has a plurality of liquid ejection units, each of which includes a liquid ejection head that ejects liquid onto the recording material, a supply sub-tank that includes a first liquid region and a first gas region therein and supplies the liquid to the liquid ejection head, and a recovery sub-tank that includes a second liquid region and a second gas region therein and recovers the liquid from the liquid ejection head; The plurality of pressure transmission paths include: a plurality of supply pressure transmission paths respectively communicating with the first gas regions of the supply sub-tanks of the plurality of liquid ejection units; a plurality of recovery pressure transmission paths respectively communicating with the second gas regions of the recovery sub-tanks of the plurality of liquid ejection units; Including, the at least one pressure measurement unit includes a first pressure measurement unit and a second pressure measurement unit; the at least one switching unit selectively switches a connection destination of a first internal space, which is the internal space of the first pressure measurement unit, from among the plurality of supply pressure transmission paths, so that the pressure sensor of the first pressure measurement unit measures the pressure of the first internal space in a state in which the first internal space is in communication with the first gas region of one of the supply sub-tanks of the plurality of liquid discharge units; a pressure sensor of the second pressure measuring unit that measures the pressure of the second internal space while the second internal space is connected to the second gas region of one of the recovery sub-tanks of the plurality of liquid ejection units;

5. 5. The recording device according to claim 4, the at least one switching unit includes a first switching unit and a second switching unit; the first switching unit selectively switches the connection destination of the first internal space of the first pressure measurement unit from among the plurality of supply pressure transmission paths, and the pressure sensor of the first pressure measurement unit measures the pressure of the first internal space in a state in which the first internal space is in communication with the first gas region of one of the supply sub-tanks of the plurality of liquid discharge units; a second switching unit selectively switching the connection destination of the second internal space of the second pressure measurement unit from among the plurality of recovery pressure transmission paths, and the pressure sensor of the second pressure measurement unit measures the pressure of the second internal space while the second internal space is connected to the second gas region of one of the recovery sub-tanks of the plurality of liquid ejection units.

6. 4. The recording device according to claim 1, the at least one liquid ejection unit has a liquid ejection head that ejects liquid onto the recording material, and a plurality of liquid ejection units each including a supply sub-tank that includes a first liquid region and a first gas region therein and supplies the liquid to the liquid ejection head; the plurality of pressure transmission paths include a plurality of supply pressure transmission paths respectively communicating with the first gas regions of the supply sub-tanks of the plurality of liquid ejection units, a pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit; a supply pressure transmission path for supplying the liquid to the at least one pressure measuring unit; a supply pressure transmission path for supplying the liquid to the at least one pressure measuring unit; a supply pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit;

7. 4. The recording device according to claim 1, the at least one liquid ejection unit has a plurality of liquid ejection units, each of which includes a liquid ejection head that ejects liquid onto the recording material, and a recovery sub-tank that includes a second liquid region and a second gas region therein and recovers the liquid from the liquid ejection head; the plurality of pressure transmission paths include a plurality of recovery pressure transmission paths respectively communicating with the second gas regions of the recovery sub-tanks of the plurality of liquid ejection units, a pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit; a pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit; a pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit;

8. 4. The recording device according to claim 1, the at least one liquid ejection unit includes a liquid ejection head that ejects liquid onto the recording material, a supply sub-tank that includes a first liquid region and a first gas region therein and supplies the liquid to the liquid ejection head, and a recovery sub-tank that includes a second liquid region and a second gas region therein and recovers the liquid from the liquid ejection head, The plurality of pressure transmission paths include: at least one supply pressure transmission path communicating with the first gas region of the supply sub-tank of the at least one liquid ejection unit; at least one recovery pressure transmission path communicating with the second gas region of the recovery sub-tank of the at least one liquid ejection unit; Including, a pressure sensor for measuring the pressure of the internal space of the at least one pressure measuring unit while the internal space is connected to the first gas region of the supply sub-tank of the at least one liquid ejection unit or the second gas region of the recovery sub-tank of the at least one liquid ejection unit, wherein the at least one switching unit selectively switches the connection destination of the internal space of the at least one pressure measuring unit from between the at least one supply pressure transmission path and the at least one recovery pressure transmission path,

9. 5. The recording device according to claim 4, the plurality of pressure transmission paths each have a pressure receiving portion that receives pressure from a gas pressure source via gas; the at least one switching unit selectively switches the connection destination of the first internal space of the first pressure measurement unit from among the plurality of supply pressure transmission paths, and the pressure sensor of the first pressure measurement unit measures the pressure of the first internal space in a state in which the first internal space is in communication with the first gas region and the pressure receiving portion of one of the supply sub-tanks of the plurality of liquid discharge units; a pressure sensor of the second pressure measuring unit that measures the pressure of the second internal space while the second internal space is connected to the second gas region and the pressure receiving portion of one of the recovery sub-tanks of the plurality of liquid ejection units;

10. 4. The recording device according to claim 1, the at least one liquid ejection unit includes a liquid ejection head that ejects liquid onto the recording material, a supply sub-tank that includes a first liquid region and a first gas region therein and supplies the liquid to the liquid ejection head, and a recovery sub-tank that includes a second liquid region and a second gas region therein and recovers the liquid from the liquid ejection head, The plurality of pressure transmission paths include: a supply pressure transmission path communicating with the first gas region of the supply sub-tank; a recovery pressure transmission path communicating with the second gas region of the recovery sub-tank; Including, the at least one pressure measurement unit includes a first pressure measurement unit and a second pressure measurement unit; a pressure sensor of the first pressure measurement unit measuring the pressure of the first internal space while the at least one switching unit connects the first internal space of the first pressure measurement unit to the supply pressure transmission path, and the pressure sensor of the first pressure measurement unit measures the pressure of the first internal space in a state where the first internal space is in communication with the first gas region of the supply sub-tank; and a pressure sensor of the second pressure measurement unit measuring the pressure of the second internal space simultaneously with measuring the pressure of the first internal space while the at least one switching unit connects the second internal space of the second pressure measurement unit to the recovery pressure transmission path, and the pressure sensor of the second pressure measurement unit measuring the pressure of the second internal space in a state where the second internal space is in communication with the second gas region of the recovery sub-tank.

11. 5. The recording device according to claim 4, A recording apparatus, wherein the volume of the first internal space of the first pressure measuring section is set to be equal to or smaller than the volume of the supply sub-tank.

12. 5. The recording device according to claim 4, A recording device, wherein the volume of the second internal space of the second pressure measuring unit is set to be equal to or smaller than the volume of the recovery sub-tank.

13. 5. The recording device according to claim 4, A recording apparatus, wherein the volume of the first internal space of the first pressure measuring unit is set to be equal to or less than the volume of the first gas region of the supply sub-tank.

14. 5. The recording device according to claim 4, A recording apparatus, wherein the volume of the second internal space of the second pressure measuring unit is set to be equal to or smaller than the volume of the second gas region of the recovery subtank.

15. 5. The recording device according to claim 4, The at least one liquid ejection unit an ink ejection unit that ejects ink as the liquid; a pretreatment liquid discharge unit that discharges a pretreatment liquid as the liquid; a post-treatment liquid discharge unit that discharges a post-treatment liquid as the liquid; A recording device comprising:

16. 5. The recording device according to claim 4, The recording device further comprises a filter disposed in the supply pressure transmission path between the first gas region of the supply sub-tank and the first internal space of the first pressure measurement unit.

17. 5. The recording device according to claim 4, a filter disposed in the recovery pressure transmission path between the second gas region of the recovery subtank and the second internal space of the second pressure measurement unit;