Pressure measurement device and recording device provided with same

Abstract

A pressure measurement device (1S) that measures the pressure of a plurality of pressure transmission paths that apply pressure to an object via a gas is provided with: at least one pressure measurement unit (1A) that includes a measurement path having an internal space capable of receiving the gas, and a pressure sensor (611) that detects the pressure of 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

Technical Field

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

[0002] Patent document 1 discloses a recording device including a liquid ejection mechanism for ejecting liquid onto a recording medium to form an image. The liquid ejection mechanism includes a liquid ejection head, a movable stage supporting the liquid ejection head and movable in a main scanning direction, and a pressure measuring device disposed on the movable stage. The pressure measuring device measures the pressure of the liquid inside the liquid ejection head, and includes a pressure transmission path connected to the liquid ejection head and a pressure sensor capable of measuring the pressure of the pressure transmission line.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-52357 Summary of the invention

[0006] An object of the present disclosure is to provide a pressure measuring device capable of measuring the pressure of a pressure transmission path by using pressure sensors whose number is smaller than the number of pressure transmission paths, and a recording device including the pressure measuring device.

[0007] A pressure measuring device involved in one aspect of the present disclosure is a pressure measuring device that measures the pressure of multiple pressure transmission paths that apply pressure to an object via a gas, and comprises: at least one pressure measuring unit, including a measurement path having an internal space capable of receiving the gas and a pressure sensor that detects the pressure of the internal space; and at least one switching unit that can selectively switch the connection destination of the measurement path from the multiple pressure transmission paths.

[0008] In addition, the recording device involved in another aspect of the present disclosure comprises: the pressure measuring device described above; the multiple pressure transmission paths; and at least one liquid ejection unit that ejects liquid onto the recording material, and the multiple pressure transmission paths respectively apply 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view showing the overall structure of a recording device according to one embodiment of the present disclosure.

[0010] Figure 2 yes Figure 1 Schematic cross-sectional view of line II-II.

[0011] Figure 3 yes Figure 1 An enlarged perspective view of the carriage is shown.

[0012] Figure 4 It is a schematic diagram showing a plurality of pressure transmission paths around a carriage according to an embodiment of the present disclosure.

[0013] Figure 5 It is a schematic diagram showing a supply sub-tank and a recovery sub-tank according to an embodiment of the present disclosure.

[0014] Figure 6 This is a schematic diagram showing the flow of liquid around a liquid ejection head according to an embodiment of the present disclosure.

[0015] Figure 7 It means Figure 4 A schematic diagram of the corresponding liquid ejection situation.

[0016] Figure 8 It means Figure 4 Schematic diagram of the corresponding purge operation. DETAILED DESCRIPTION

[0017] Hereinafter, the pressure measuring device and the recording device involved in each embodiment of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, as a specific example of the recording device, an inkjet printer having an ink jet head that ejects ink for image formation onto a wide and long recording medium is illustrated. The inkjet printer is suitable for digital printing and dyeing of images such as text and patterns on a recording medium composed of fabrics such as woven fabrics by inkjet liquid. Of course, the recording device involved in the present disclosure can also be used for printing various images on recording media such as paper sheets and resin sheets.

[0018] [Overall structure of an inkjet printer]

[0019] Figure 1 is a perspective view showing the overall structure of an inkjet printer 1 according to a first embodiment of the present disclosure. Figure 2 for Figure 1 The schematic cross-sectional view of the line II-II of FIG. The inkjet printer 1 is a printer that prints an image on a wide and long workpiece W (recording medium) by inkjet liquid, and includes a device frame 10, a workpiece conveying unit 20 (conveying unit) assembled to the device frame 10, and a carriage 3. In addition, in the present embodiment, the left-right direction is the main scanning direction S ( Figure 3 ), the direction from the rear to the front is the sub-scanning direction (the direction intersecting the main scanning direction S, ie, the conveying direction F of the workpiece W).

[0020] The device frame 10 forms a framework for mounting various structural members of the inkjet printer 1. The workpiece conveying unit 20 is a mechanism for intermittently conveying (conveying) the workpiece W in the printing area where the inkjet printing process is performed so that the workpiece W moves along the conveying direction F from the rear to the front. The carriage 3 carries the inkjet head 4, the pre-treatment liquid head 5, the post-treatment liquid head 6, and the sub-tank 7, and reciprocates in the main scanning direction S (left-right direction) intersecting the conveying direction F of the workpiece W during the inkjet printing process.

[0021] 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 structural components of the inkjet printer 1, and has a left-right width corresponding to the workpiece conveying unit 20. The right frame 112 and the left frame 113 are respectively erected on the right and left sides of the central frame 111. Between the right frame 112 and the left frame 113 is a printing area 12 for performing printing processing on the workpiece W.

[0022] The right frame 112 forms a 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, the nozzles (ejection holes) of the ink jet head 4, the pre-treatment liquid jet head 5, and the post-treatment liquid jet head 6 are cleaned, purged, etc., and capping is also performed. The left frame 113 forms a return area 14 for the carriage 3. The return area 14 is an area where the carriage 3, which has performed a main scan on the printing area 12 from the right to the left in the printing process, temporarily enters when performing a main scan in the opposite direction.

[0023] A carriage guide 15 for reciprocating the carriage 3 in the left-right direction is assembled on 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 arranged above the workpiece conveying unit 20. The timing belt 16 is assembled to the carriage guide 15 so as to be able to be wound and moved in the left-right direction (main scanning direction). The timing belt 16 is an endless belt, and is driven so as to be wound and moved in the left or right direction.

[0024] The carriage guide 15 is provided with a pair of upper and lower guide rails 17 that hold the carriage 3 in a state of being reciprocating in the main scanning direction S, so that the guide rails 17 extend parallel to the left-right direction. The carriage 3 is engaged with the guide rails 17. In addition, the carriage 3 is fixed to the timing belt 16. The carriage 3 moves in the left direction or the right direction along the carriage guide 15 while being guided by the guide rails 17 as the timing belt 16 is wound in the left direction or the right direction.

[0025] Main reference Figure 2The workpiece conveying unit 20 includes a delivery roller 21 for delivering the workpiece W before printing and a winding roller 22 for winding the workpiece W after printing. The delivery roller 21 is arranged at the rear lower part of the device frame 10, and is the winding body of the workpiece W before printing, that is, the winding shaft of the delivery roller WA. The winding roller 22 is arranged at the front lower part of the device frame 10, and is the winding body of the workpiece W after printing, that is, the winding shaft of the winding roller WB. A first motor M1 is attached to the winding roller 22, and the first motor M1 drives the winding roller 22 to rotate around the axis to perform the winding action of the workpiece W.

[0026] The path between the delivery roller 21 and the take-up roller 22 and passing through the printing area 12 is a conveying path for the workpiece W. On this conveying path, a first tension roller 23, a workpiece guide 24, a conveying roller 25, a pinch roller 26, a return roller 27, and a second tension roller 28 are arranged in order from the upstream side. The first tension roller 23 applies a given tension to the workpiece W on the upstream side of the conveying roller 25. The workpiece guide 24 changes the conveying direction of the workpiece W from the upper direction to the front direction, so that the workpiece W is carried into the printing area 12.

[0027] The conveying roller 25 is a roller that generates a conveying force for intermittently conveying the workpiece W in the printing area 12. The conveying roller 25 is driven to rotate about an axis by the second motor M2, and intermittently conveys the workpiece W in the forward direction (a given conveying direction F) so that the workpiece W passes through the printing area 12 (image forming position) opposite to the carriage 3. The pinch roller 26 is arranged to face the conveying roller 25 from above, and forms a conveying nip portion with the conveying roller 25.

[0028] The return roller 27 changes the conveying direction of the workpiece W passing through the printing area 12 from the front direction to the downward direction, and guides the workpiece W after the printing process to the winding roller 22. The second tension roller 28 applies a given tension to the workpiece W on the downstream side of the conveying roller 25. In the printing area 12, a platen 29 is arranged below the conveying path of the workpiece W.

[0029] The carriage 3 reciprocates in a main scanning direction S (in the present embodiment, the left-right direction) intersecting (in the present embodiment, orthogonal) with the conveying direction F while being cantilevered by the guide rail 17. The carriage 3 includes a carriage frame 30, an ink jet head 4, a pre-treatment liquid jet head 5, a post-treatment liquid jet head 6, and a sub-tank 7 ( Figure 3 ). The carriage frame 30 includes a nozzle support frame 31 and a back frame 32.

[0030] The nozzle support frame 31 is a horizontal plate that holds the nozzles 4 to 6. The back frame 32 is a vertical plate that extends upward from the rear end edge of the nozzle support frame 31. As described above, the timing belt 16 is fixed to the back frame 32. In addition, the guide rail 17 is engaged with the back frame 32. That is, in the present embodiment, the back frame 32 is an engaging portion that is held in a cantilever state on the guide rail 17. The nozzle support frame 31 is a horizontal plate whose rear end side is cantilevered on the guide rail 17 through the engaging portion.

[0031] In addition, the cantilever state means a state in which the engaging portion (back frame 32) as the portion held by the holding member, that is, the guide rail 17, in the carriage 3 exists only on one side of the upstream side or the downstream side from the center of the carriage 3 in the conveying direction F, and no other engaging portion exists on the side opposite to the side where the engaging portion exists. The engaging portion may be arranged at a position outside the range where the ink jet head 4 and the processing head are arranged in the conveying direction F. That is, the engaging portion may be arranged only on the upstream side or only on the downstream side relative to the range where the ink jet head 4 and the processing head are arranged in the conveying direction F.

[0032] [the details of the carriage]

[0033] The carriage 3 will be further described. Figure 3 yes Figure 1 An enlarged perspective view of the carriage 3 is shown. Figure 3 , the conveying direction F (sub-scanning direction) of the workpiece W and the main scanning direction S which is the moving direction of the carriage 3 are shown. Figure 3 In the figure, there is shown an example in which a plurality of ink nozzles 4 for ejecting ink for image formation onto a workpiece W, a pre-treatment liquid nozzle 5 and a post-treatment liquid nozzle 6 for ejecting a non-color developing treatment liquid, and a plurality of sub-tanks 7 for supplying the ink and the treatment liquid to these nozzles 4 to 6 are mounted on a slide 3.

[0034] The inkjet heads 4 each have a plurality of nozzles (ink ejection holes) for ejecting ink droplets in an ejection method such as a piezoelectric method using a piezoelectric element or a thermal method using a heating element, and an ink passage for guiding the ink to the nozzle. As the ink, for example, an aqueous pigment ink including an aqueous solvent, a pigment, and a binding resin can be used. The plurality of inkjet heads 4 in this embodiment can eject inks of eight colors. The inkjet heads 4 are mounted on a nozzle support frame 31 of the carriage 3 so as to be arranged in two rows in the main scanning direction S. Each color of the inkjet heads 4 has two inkjet heads.

[0035] Specifically, the ink jet head 4 has a first upstream ink jet head 41A and a first downstream ink jet head 41B. These ink jet heads 4 eject yellow ink. In addition, the ink jet head 4 has a second upstream ink jet head 42A and a second downstream ink jet head 42B. These ink jet heads 4 eject magenta ink. Similarly, Figure 3 As shown, two ink jet heads 4 ejecting ink of the same color are arranged at positions offset from each other in the conveying direction F and the main scanning direction S. The two ink jet heads 4 are regarded as one group, and a total of eight groups of ink jet heads 4 (41A to 48A, 41B to 48B) eject ink of different colors.

[0036] The pre-treatment liquid ejection head 5 and the post-treatment liquid ejection head 6 are arranged at different positions from the ink ejection head 4 in the conveying direction F. The pre-treatment liquid ejection head 5 is arranged on the upstream side of the ink ejection head 4 in the conveying direction F. Figure 3 , an example is shown in which the pre-treatment liquid ejection head 5 is arranged near the left end of the array of the ink ejection head 4. Similarly, the post-treatment liquid ejection head 6 is arranged on the downstream side of the ink ejection head 4 in the conveying direction F. Figure 3 , an example is shown in which a post-treatment liquid nozzle 6 is arranged at the right end of the array of ink nozzles 4. In other embodiments, multiple pre-treatment liquid nozzles 5 or multiple post-treatment liquid nozzles 6 may be arranged. Preferably, at least one pre-treatment liquid nozzle 5 and at least one post-treatment liquid nozzle 6 are respectively provided on the carriage 3, but in other embodiments, the pre-treatment liquid nozzle 5 and the post-treatment liquid nozzle 6 may not be arranged.

[0037] In addition, a series of heads along the main scanning direction S composed of the ink jet head 4, the pre-treatment liquid jet head 5, and the post-treatment liquid jet head 6 is referred to as a head column, or simply a column. In addition, a series of heads along the conveying direction F composed of the ink jet head 4, the pre-treatment liquid jet head 5, and the post-treatment liquid jet head 6 is referred to as a head row, or simply a row.

[0038] The pretreatment liquid ejection head 5 ejects a pretreatment liquid for performing a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the pretreatment liquid ejection head 5 to a position of the workpiece W from the ink ejection head 4 to which the ink has not yet been ejected from the ink ejection head 4. The pretreatment liquid is a non-color developing treatment liquid that does not develop color even when attached to the workpiece W, and is, for example, a treatment liquid that exhibits a function of improving the fixability of the ink to the workpiece W and the cohesion of the ink pigment. As such a pretreatment liquid, a treatment liquid prepared with a binder resin in a solvent, a treatment liquid prepared with a positively charged cationic resin in a solvent, and the like can be used.

[0039] The post-treatment liquid nozzle 6 ejects a post-treatment liquid for performing a given post-treatment on the workpiece W to which the ink is attached. The post-treatment liquid is ejected from the post-treatment liquid nozzle 6 to the position of the workpiece W after the ink is ejected from the ink nozzle 4. The post-treatment liquid is also a non-color developing treatment liquid that does not develop color even if attached to the workpiece W, and is a treatment liquid that exhibits the function of improving the fixability and firmness (resistance to friction and cutting) of the ink image printed on the workpiece W by the ink nozzle 4. As such a post-treatment liquid, a silicone-based treatment liquid or the like can be used. In addition, the post-treatment liquid and the pre-treatment liquid are different treatment liquids. Specifically, the components contained in the post-treatment liquid and the pre-treatment liquid are different.

[0040] Here, the non-color developing treatment liquid refers to a treatment liquid that cannot be recognized as color developing by the naked eye when printed on a recording medium alone. The colors here also include colors with a saturation of 0, such as black, white, and gray. The non-color developing treatment liquid is basically a transparent liquid, but for example, when observing 1 liter of the treatment liquid in a liquid state, it is sometimes not completely transparent, but slightly appears white. Such a color is very light, so when printed on a recording medium alone, it cannot be recognized as color developing by the naked eye. In addition, depending on the type of treatment liquid, when printing on a recording medium alone, there may be changes in the gloss of the recording medium, but such a state is not color developing.

[0041] In the present embodiment, the pre-treatment liquid and the post-treatment liquid may be ejected onto substantially the entire surface of the workpiece W. The pre-treatment liquid and the post-treatment liquid may also be ejected selectively according to the image to be printed, similar to the ink.

[0042] Next, the case of selectively ejecting the pre-treatment liquid and the post-treatment liquid is described. As described above, the pre-treatment liquid, the ink, and the post-treatment liquid are ejected to the portion of the workpiece W where the color corresponding to the image is printed in the order of the pre-treatment liquid, the ink, and the post-treatment liquid. In this case, the ink is one color or a plurality of colors. In the portion where the color is not printed, that is, the portion where the ink is not ejected, the pre-treatment liquid and the post-treatment liquid are basically not ejected. In addition, in order to adjust the image quality of the printed image, the feel of the workpiece W, etc., a part of the selection of ejecting the pre-treatment liquid and the post-treatment liquid can also be different from the ejection of the ink.

[0043] like Figure 3 As shown, an opening 31H is provided at the head arrangement portion of the head support frame 31. The inkjet head 4, the pre-treatment liquid head 5, and the post-treatment liquid head 6 are assembled to the head support frame 31 so as to fit into each opening 31H. The nozzles arranged at the lower end surfaces of the inkjet heads 4, 5, and 6 are exposed from each opening 31H.

[0044] The plurality of sub-tanks 7 are supported by the carriage 3 above the ink jet heads 4, 5, and 6 via a holding frame (not shown). The plurality of sub-tanks 7 are provided corresponding to the ink jet heads 4, 5, and 6, respectively. Ink or processing liquid is supplied to each sub-tank 7 from a main tank 90 described later containing ink and processing liquid, and is supplied to the ink jet heads 4, 5, and 6, respectively. Each sub-tank 7 is connected to the ink jet heads 4, 5, and 6 via a main tank 90 (not shown). Figure 3 The pipes shown in the figure are omitted for connection.

[0045] Specifically, the plurality of sub-tanks 7 include the first supply sub-tank 71A to the eighth supply sub-tank 78A, the pre-processing supply sub-tank 7FA, and the post-processing supply sub-tank 7RA, which are arranged on the rear side along the main scanning direction S. Furthermore, the plurality of sub-tanks 7 include the first recovery sub-tank 71B to the eighth recovery sub-tank 78B, the pre-processing recovery sub-tank 7FB, and the post-processing recovery sub-tank 7RB, which are arranged on the front side along the main scanning direction S.

[0046] The first supply sub-tank 71A and the first recovery sub-tank 71B located on the leftmost side of the carriage 3 contain yellow ink. The first supply sub-tank 71A supplies yellow ink to the first upstream ink jet head 41A and the first downstream ink jet head 41B. On the other hand, the first recovery sub-tank 71B recovers yellow ink from the first upstream ink jet head 41A and the first downstream ink jet head 41B. At this time, a portion of the yellow ink is ejected from the first upstream ink jet head 41A and the first downstream ink jet head 41B to the workpiece W. Similarly, the second supply sub-tank 72A supplies magenta ink to the second upstream ink jet head 42A and the second downstream ink jet head 42B. On the other hand, the second recovery sub-tank 72B recovers magenta ink from the second upstream ink jet head 42A and the second downstream ink jet head 42B. Each of the other third sub-tanks to each of the eighth sub-tanks also has the same structure and function as described above.

[0047] The pre-treatment supply sub-tank 7FA supplies the pre-treatment liquid to the pre-treatment liquid nozzle 5, and the pre-treatment recovery sub-tank 7FB recovers the pre-treatment liquid from the pre-treatment liquid nozzle 5. The post-treatment supply sub-tank 7RA supplies the post-treatment liquid to the post-treatment liquid nozzle 6, and the post-treatment recovery sub-tank 7RB recovers the post-treatment liquid from the post-treatment liquid nozzle 6.

[0048] As described above, the inkjet printer 1 according to the present embodiment is an all-in-one printer in which three types of nozzles, namely, the ink nozzle 4, the pre-treatment liquid nozzle 5, and the post-treatment liquid nozzle 6, are mounted on a carriage 3. According to the inkjet printer 1, for example, in the printing and dyeing process of inkjet printing on cloth in digital printing and dyeing, the pre-treatment liquid ejection process and the post-treatment liquid ejection process can be performed in one body. Therefore, the printing and dyeing process can be simplified and the printing and dyeing device can be made compact.

[0049] In addition, the inkjet printer 1 according to the present embodiment performs a printing process on the workpiece W in a serial printing method. Specifically, when the workpiece W has a wide size, it is impossible to print while continuously conveying the workpiece W. The serial printing method is a printing method in which the carriage 3 equipped with the inkjet heads 4 of each color repeatedly reciprocates in the main scanning direction S and the workpiece W is intermittently conveyed in the conveying direction F.

[0050] Specifically, the carriage 3 prints a band-shaped image while moving in one direction of the main scanning direction S, namely, the outward direction. During the main scanning in the outward direction, the feeding of the workpiece W stops. After the printing of the band-shaped image, the workpiece W is sent out along the conveying direction F at a given spacing. At this time, the carriage 3 waits in the return area 14 on the left end side. After the workpiece W is sent out, the carriage 3 turns back in the return direction opposite to the outward direction as the synchronous belt 16 turns over. The workpiece W is in a stopped state. Then, the carriage 3 moves in the return direction, and at the same time, prints the next band-shaped image on the upstream side of the band-shaped image. The same action is repeated below.

[0051] Next, refer to Figures 4 to 6 The supply of pressure and ink to each ink ejecting head 4 according to the present embodiment will be described. Figure 4 It is a schematic diagram showing a plurality of pressure transmission paths around the carriage 3 according to the present embodiment. Figure 5 It is a schematic diagram showing the supply sub-tank and the recovery sub-tank according to the present embodiment. Figure 6 Schematic diagrams showing the flow of ink around the liquid ejection head according to the present embodiment. In each figure, the lines connecting the components represent conduits (tubes) through which gas or liquid flows.

[0052] In this embodiment, the gas (air) is used to carry Figure 3 The first supply sub-tank 71A to the post-processing supply sub-tank 7RA and the first recovery sub-tank 71B to the post-processing recovery sub-tank 7RB on the carriage 3 are respectively pressurized. As a result, the liquid (ink, pre-processing liquid, post-processing liquid) is supplied from each supply sub-tank to the ink jet head 4, the pre-processing liquid jet head 5, and the post-processing liquid jet head 6. First, refer to Figure 4 , the pressure supply path to each sub-tank 7 will be described.

[0053] 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 process liquid supply regulator 57, and a process liquid recovery regulator 58. These devices or components are arranged on the device frame 10 ( Figure 1 ).

[0054] The control unit 100 controls the operation of the inkjet printer 1 and Figure 4 The components shown are electrically controlled.

[0055] The compressor 50 generates pressure to be supplied to each sub-tank 7, compresses the gas to increase the pressure, and continuously delivers it. A known reciprocating compressor or rotary compressor can be used as the compressor 50. As an example, the compressor pressure is set to 500 to 800 kPa.

[0056] The filter 51 removes foreign matter, dust, etc. contained in the gas ejected from the compressor 50. As an example, the opening diameter of the filter 51 is set to 5 μm. The gas after passing through the filter 51 flows into three flow paths, namely, the first main pressure supply path P01, the second main pressure supply path P02, and the purge pressure supply path P03.

[0057] The purge main regulator 52 is arranged downstream of the filter 51 in the flow path of the gas, and is a regulator for adjusting the pressure of the purge pressure supply path P03. Similarly, the first main regulator 53 is a regulator arranged downstream of the filter 51 in the flow of the gas, and is used to adjust the pressure of the first main pressure supply path P01. Similarly, the second main regulator 54 is a regulator arranged downstream of the filter 51 in the flow of the gas, and is used to adjust the pressure of the second main pressure supply path P02. In addition, as an example, the purge main regulator 52, the first main regulator 53 and the second main regulator 54 are NPN type regulators with open collector outputs. These regulators receive a command signal from the control unit 100 and open the valve so that each flow path is adjusted to a pressure corresponding to the signal.

[0058] like Figure 4 As shown, the first main pressure supply path P01 is divided into eight flow paths corresponding to the first supply sub-tank 71A to the eighth supply sub-tank 78A on the downstream side of the first main regulator 53. Figure 4 , 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 of the eight flow paths are illustrated, and the illustration of other flow paths is omitted. The first supply side pressure supply path P11 is a flow path extending from the first main pressure supply path P01 (first main regulator 53) to the first supply sub-tank 71A. Similarly, the second supply side pressure supply path P21 is a flow path extending from the first main pressure supply path P01 to the second supply sub-tank 72A. In addition, the eighth supply side pressure supply path P81 extends from the first main pressure supply path P01 to the eighth supply sub-tank 78A ( Figure 3 ) flow path.

[0059] The ink supply regulator 55 is disposed on each supply side pressure supply path and has the function of adjusting the pressure supplied to each ink supply sub-tank. As an example, the ink supply regulator 55 is composed of an electric pneumatic regulator. Figure 4 , the first ink supply regulator 551, the second ink supply regulator 552, and the 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, and the illustration of other ink supply regulators is omitted. These regulators receive command signals from the control unit 100 and open valves so that each flow path is adjusted to a pressure corresponding to the signal. In addition, as an example, the target pressure applied to the supply sub-tank by each ink supply regulator 55 is set to 15 kPa.

[0060] On the other hand, the second main pressure supply path P02 is divided into 12 paths on the downstream side 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. Figure 4 , 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 pretreatment liquid pressure supply path PFA, the pretreatment liquid pressure recovery path PFB, the post-treatment liquid pressure supply path PRA, and the post-treatment liquid pressure recovery path PRB of the 12 flow paths are illustrated, and the illustration of other flow paths is omitted. 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 path P22 is a flow path extending from the second main pressure supply path P02 to the second recovery sub-tank 72B. In addition, the eighth recovery side pressure supply path P82 is a flow path extending from the second main pressure supply path P02 to the eighth recovery sub-tank 78B. Furthermore, the pre-treatment liquid pressure supply path PFA is a flow path extending from the second main pressure supply path P02 (second main regulator 54) to the pre-treatment supply sub-tank 7FA, and the pre-treatment liquid pressure recovery path PFB is a flow path extending from the second main pressure supply path P02 to the pre-treatment recovery sub-tank 7FB. In addition, the post-treatment liquid pressure supply path PRA is a flow path extending from the second main pressure supply path P02 to the post-treatment supply sub-tank 7RA, and the post-treatment liquid pressure recovery path PRB is a flow path extending from the second main pressure supply path P02 to the post-treatment recovery sub-tank 7RB.

[0061] The ink recovery regulator 56 is disposed on each recovery side pressure supply path and has the function of adjusting the pressure supplied to each ink recovery sub-tank. As an example, the ink recovery regulator 56 is composed of an electric pneumatic regulator. Figure 4In the figure, the first ink recovery regulator 561, the second ink recovery regulator 562, and the eighth ink recovery regulator 568 are illustrated corresponding to the first recovery side pressure supply path P12, the second recovery side pressure supply path P22, and the eighth recovery side pressure supply path P82, and the illustration of other ink recovery regulators is omitted. These regulators receive the command signal from the control unit 100 and open the valve so that each flow path is adjusted to the pressure corresponding to the signal. In addition, as an example, the target pressure applied by each ink recovery regulator 56 to the recovery sub-tank of each ink is set to -20kPa.

[0062] Similarly, the process liquid supply regulator 57 (pre-process liquid supply regulator 571, post-process liquid supply regulator 572) is arranged on the supply side pressure supply path of each process liquid, and the process liquid recovery regulator 58 (pre-process liquid recovery regulator 581, post-process liquid recovery regulator 582) is arranged on the recovery side pressure supply path of each process liquid. These regulators also have the same structure and function as the ink supply regulator 55 and ink recovery regulator 56. In addition, as an example, the target pressure applied by the process liquid supply regulator 57 and the process liquid recovery regulator 58 to each process liquid sub-tank is set to -5kPa.

[0063] Furthermore, the path on the carriage 3 in the above-mentioned pressure transmission path will be described. Figure 4 As shown, the inkjet printer 1 also has a first pressure measuring unit 1A, a second pressure measuring unit 1B, a third pressure measuring unit 1C, an ink supply purge valve 62, an ink supply measuring valve 63, an ink recovery purge valve 64, an ink recovery measuring valve 65, a processing liquid purge valve 66, and a processing liquid measuring valve 67, which are arranged on the slide 3.

[0064] The first pressure measuring unit 1A includes a first pressure sensor 611 and a first pressure measuring path M01. The second pressure measuring unit 1B includes a second pressure sensor 612 and a second pressure measuring path M02. The third pressure measuring unit 1C includes a third pressure sensor 613 and a third pressure measuring path M03.

[0065] The first pressure sensor 611 measures the pressure of the first pressure measuring 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 of the second pressure measuring path M02, and inputs a signal corresponding to the measurement result to the control unit 100. The third pressure sensor 613 measures the pressure of the third pressure measuring path M03, and inputs a signal corresponding to the measurement result to the control unit 100. The first pressure measuring path M01 can be connected to any one of the first supply side pressure supply path P11 to the eighth supply side pressure supply path P81 according to the opening and closing of the ink supply measuring valve 63. Similarly, the second pressure measuring path M02 can be connected to any one of the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82 according to the opening and closing of the ink recovery measuring valve 65. The third pressure measurement path M03 can communicate with any one of 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 according to the opening and closing of the treatment liquid measurement valve 67 .

[0066] The ink supply purge valves 62 are eight valves for connecting the purge pressure supply path P03 to any one of the first supply side pressure supply path P11 to the eighth supply side pressure supply path P81. Figure 4 As shown, the ink supply purge valve 62 includes a first ink supply purge valve 621 disposed on the first supply side pressure supply path P11 and a second ink supply purge valve 622 disposed on the second supply side pressure supply path P21. In addition, these valves are respectively constituted by a known three-way solenoid valve. In this embodiment, 20 three-way solenoid valves are configured as 20 series of three-way solenoid valves together with the ink recovery purge valve 64 and the processing liquid purge valve 66 in one valve unit.

[0067] As described above, the ink supply measurement valve 63 is composed of eight valves for connecting the first pressure measurement path M01 to any one of the first supply side pressure supply path P11 to the eighth supply side pressure supply path P81. Figure 4 As shown, the ink supply measuring valve 63 includes a first ink supply measuring valve 631 connected to the first supply side pressure supply path P11 and a second ink supply measuring valve 632 connected to the second supply side pressure supply path P21. In addition, these valves are respectively composed of well-known two-way electromagnetic valves. In this embodiment, eight two-way electromagnetic valves are arranged in one valve unit as eight series of two-way electromagnetic valves.

[0068] The ink recovery purge valve 64 is a valve for connecting the purge pressure supply path P03 to any one of the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82. Figure 4As shown, the ink recovery purge valve 64 includes a first ink recovery purge valve 641 configured on the first recovery side pressure supply path P12 and a second ink recovery purge valve 642 configured on the second recovery side pressure supply path P22. These valves are respectively composed of a known three-way electromagnetic valve. In addition, between the first ink recovery purge valve 641 and the first ink recovery regulator 561, a vacuum ejector not shown is configured to be interposed therebetween. The same is true between other recovery valves and recovery regulators.

[0069] As described above, the ink recovery measuring valve 65 is composed of eight valves for connecting the second pressure measuring path M02 to any one of the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82. Figure 4 As shown, the ink recovery measuring valve 65 includes a first ink recovery measuring valve 651 connected to the first recovery side pressure supply path P12 and a second ink recovery measuring valve 652 connected to the second recovery side pressure supply path P22. In addition, these valves are respectively composed of well-known two-way solenoid valves. In this embodiment, eight two-way solenoid valves are arranged in one valve unit as eight series of two-way solenoid valves.

[0070] The treatment liquid purge valve 66 is a valve used to connect the purge pressure supply path P03 with any one of 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. Figure 4 As shown, the treatment liquid exhaust valve 66 includes a first treatment liquid purge valve 661 connected to the pretreatment liquid pressure supply path PFA and a second treatment liquid purge valve 662 connected to the pretreatment liquid pressure recovery path PFB. As described above, these valves are respectively constituted by a well-known three-way electromagnetic valve.

[0071] The treatment liquid measuring valve 67 is a valve for connecting the third pressure measuring path M03 to any one of 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. Figure 4 As shown, the treatment liquid measuring valve 67 includes a first treatment liquid measuring valve 671 connected to the pretreatment liquid pressure supply path PFA and a second treatment liquid measuring valve 672 connected to the pretreatment liquid pressure recovery path PFB. In addition, these valves are respectively composed of well-known two-way solenoid valves. In this embodiment, four two-way solenoid valves are configured as four series of two-way solenoid valves in one valve unit.

[0072] Next, refer to Figure 5 The structure of the sub-tank 7 will be further described. In the following description, the first supply sub-tank 71A and the first recovery sub-tank 71B for supplying and recovering yellow ink are described as an example, but the structures of the other sub-tanks 7 are also the same.

[0073] The first supply sub-tank 71A has a box-shaped structure. If 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 a space above the liquid surface of the yellow ink in the first supply sub-tank 71A, and the supply tank ink area SB is an 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. In addition, the supply tank ink area SB is respectively connected to the ink supply path QA (first ink path Q1, second ink path Q2), the ink circulation path Q3, and the ink replenishment path Q4 described later.

[0074] The first supply sub-tank 71A includes an electrostatic capacitance sensor 71A that can detect the liquid level (ink amount) of the yellow ink in the first supply sub-tank 71A.

[0075] Similarly, the first recovery sub-tank 71B has a box-shaped structure, and if yellow ink is stored therein, a recovery tank gas area SC and a recovery tank ink area SD are formed. The recovery tank gas area SC is a space above the liquid surface of the yellow ink in the first recovery sub-tank 71B, and the recovery tank ink area SD is an area formed by the yellow ink. The recovery tank gas area SC is connected to the first recovery side pressure supply path P12 described above. In addition, the recovery tank ink area SD is respectively connected to the ink recovery path QB (the first ink path Q1, the second ink path Q2) and the ink circulation path Q3 described later.

[0076] The first recovery sub-tank 71B includes an electrostatic capacitance sensor 71B1 capable of detecting the liquid level (ink amount) of the yellow ink in the first recovery sub-tank 71B.

[0077] Next, refer to Figure 6 , explaining the supply and recovery paths of yellow ink to the first upstream ink jet head 41A and the first downstream ink jet head 41B. In addition, ink jet heads of other colors are also provided with the same Figure 6 The inkjet printer 1 also includes filters 81, 82, 83, 84, a circulation pump 85, a check valve 86, and a deaerator 87 arranged on the carriage 3. In addition, the inkjet printer 1 also includes a device frame 10 ( Figure 1 ) of the main tank 90, the electrostatic capacitance sensor 91, the main tank valve 92 and the main supply pump 93.

[0078] The yellow ink flowing into the ink supply path QA from the first supply sub-tank 71A is divided into the first ink path Q1 via the first upstream inkjet head 41A and the second ink path Q2 via the first downstream inkjet head 41B. The filter 81 is arranged on the upstream side of the first upstream inkjet head 41A, and the filter 82 is arranged on the upstream side of the first downstream inkjet head 41B. In addition, the filter 83 is arranged on the downstream side of the first upstream inkjet head 41A, and the filter 84 is arranged on the downstream side of the first downstream inkjet head 41B. These filters have the function of removing foreign matter, dust, etc. in the ink. After a part of the yellow ink is ejected from the first upstream inkjet head 41A and the first downstream inkjet head 41B to the workpiece W, the rest of the ink is recovered from the ink recovery path QB to the first recovery sub-tank 71B.

[0079] On the other hand, if the control unit 100 detects the capacitance sensor 71A1 ( Figure 5 ) determines that there is less ink in the first supply sub-tank 71A, the circulation pump 85 operates according to the command signal input from the control unit 100. As a result, a part of the yellow ink in the first recovery sub-tank 71B is supplied to the first supply sub-tank 71A through the ink circulation path Q3. The check valve 86 makes it difficult for the ink to flow back from the first supply sub-tank 71A to the first recovery sub-tank 71B in the ink circulation path Q3. In addition, the degasser 87 removes bubbles and the like in the ink flowing into the first supply sub-tank 71A.

[0080] Furthermore, when the control unit 100 determines that the amount of yellow ink in both the first supply sub-tank 71A and the first recovery sub-tank 71B is lower than a preset threshold value based on the detection results of the electrostatic capacitance sensors 71A1 and 71B1, the control unit 100 operates the main supply pump 93, thereby replenishing the yellow ink from the main tank 90 to the first supply sub-tank 71A through the ink replenishment path Q4. In addition, the main tank valve 92 is opened so as to adjust the maximum replenishment amount (replenishment speed) relative to the first supply sub-tank 71A. In addition, when the electrostatic capacitance sensor 91 detects that the remaining amount of yellow ink in the main tank 90 is small, the control unit 100 causes the display unit (not shown) of the inkjet printer 1 to display an ink replenishment message.

[0081] <About the pressure transmission path during printing>

[0082] Figure 7 For Figure 4 The corresponding schematic diagram shows the situation during printing (liquid ejection). Figure 7 In the description, the sub-tanks 7 corresponding to yellow ink (the first supply sub-tank 71A and the first recovery sub-tank 71B) and the sub-tanks 7 corresponding to magenta ink (the second supply sub-tank 72A and the second recovery sub-tank 72B) are described. The same is true for other colors.

[0083] When the inkjet printer 1 ejects ink onto the workpiece W and performs printing, Figure 7 As shown, 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. In addition, 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 path P11, the first recovery side pressure supply path P12, the second supply side pressure supply path P21, and the second recovery side pressure supply path P22 are cut off relative to the purge pressure supply path P03.

[0084] As a result, the regulated pressure of the first ink supply regulator 551 is applied to the yellow ink in the supply tank ink area SB via the supply tank gas area SA of the first supply sub-tank 71A. Similarly, the regulated pressure of the first ink recovery regulator 561 is applied to the yellow ink in the recovery tank ink area SD via the recovery tank gas area SC of the first recovery sub-tank 71B. Figure 5 , Figure 6 As shown, the ink inside each of the first upstream ink jet head 41A and the first downstream ink jet head 41B is adjusted to a given pressure via the ink supply path QA and the ink recovery path QB, thereby reducing the possibility of accidental ejection of ink from the nozzles of the ink jet heads.

[0085] Furthermore, in the present embodiment, during the printing operation, the control unit 100 opens the ink supply measuring valve 63 and the ink recovery measuring valve 65 in sequence. Figure 7 As shown, the first ink supply measuring valve 631 connects the first supply side pressure supply path P11 with the first pressure measuring path M01, and on the other hand, the other valves of the ink supply measuring valve 63 represented by the second ink supply measuring valve 632 are set to a closed state. In this state, the pressure of the first pressure measuring path M01 is measured by the first pressure sensor 611, and the pressure applied to the supply tank ink area SB through the supply tank gas area SA of the first supply sub-tank 71A can be measured. Similarly, the first ink recovery measuring valve 651 connects the first recovery side pressure supply path P12 with the second pressure measuring path M02, and on the other hand, the other valves of the ink recovery measuring valve 65 represented by the second ink recovery measuring valve 652 are set to a closed state. In this state, the second pressure sensor 612 measures the pressure of the second pressure measuring path M02, thereby measuring the pressure applied to the recovery tank ink area SD through the recovery tank gas area SC of the first recovery sub-tank 71B.

[0086] Next, the control unit 100 controls each valve to close the first ink supply measuring valve 631 and open the second ink supply measuring valve 632, and to close the first ink recovery measuring valve 651 and open the second ink recovery measuring valve 652. In this state, the first pressure sensor 611 measures the pressure of the first pressure measuring path M01, thereby being able to measure the pressure applied to the supply tank ink area SB through the supply tank gas area SA of the second supply sub-tank 72A. In addition, the pressure applied to the recovery tank ink area SD through the recovery tank gas area SC of the second recovery sub-tank 72B can be measured by measuring the pressure of the second pressure measuring path M02 through the second pressure sensor 612. Thereafter, the pressure applied to the ink of each color of the supply sub-tank and the recovery sub-tank can be measured in sequence.

[0087] The control unit 100 adjusts the opening of each ink supply regulator 55 and each ink recovery regulator 56 based on the PID control according to the pressure measured as described above, thereby adjusting the pressure applied to each sub-tank, and as a result, it is possible to adjust the pressure of the ink applied to the ink jet head 4. The pressure measurement and pressure adjustment of each process liquid sub-tank and each process liquid head using the third pressure sensor 613 and the process liquid measuring valve 67 are also the same.

[0088] <About the pressure transmission path during purge operation>

[0089] Figure 8 It means Figure 4 Schematic diagram of the corresponding purge operation. The purge operation is an operation to apply a higher pressure than during printing to the ink ejection head 4 to release or prevent ink clogging in the ink ejection head 4 and eject ink from the nozzles of the ink ejection head 4. Figure 8 When the purge pressure is applied to the first upstream ink ejection head 41A and the first downstream ink ejection head 41B, the control unit 100 opens the first ink supply purge valve 621 of the ink supply purge valve 62, and connects the first supply side pressure supply path P11 with the purge pressure supply path P03, so that the purge pressure adjusted in the purge main regulator 52 acts on the first supply side pressure supply path P11. At this time, in order to reduce the possibility of the first pressure sensor 611 being damaged by the purge pressure, the first ink supply measuring valve 631 is closed.

[0090] On the other hand, in the first recovery side pressure supply path P12 connected to the first recovery sub-tank 71B, the first ink recovery measuring valve 651 is similarly closed to reduce the possibility of applying the purge pressure to the second pressure sensor 612. In addition, the first ink recovery purge valve 641 connects the first recovery side pressure supply path P12 to the first ink recovery regulator 561.

[0091] At this time, the upstream side of the first recovery sub-tank 71B ( Figure 8 A two-way solenoid valve (not shown) is arranged between the first recovery sub-tank 71B and the first ink recovery measuring valve 651, and the two-way solenoid valve is closed when the purge pressure is applied to each ink nozzle through the first supply side pressure supply path P11. Figure 6 The above-mentioned two-way solenoid valve is configured in the ink recovery path QB) and the same switching is performed. As a result, the purge pressure can be applied to each ink ejection head from the supply side while the path on the recovery side is closed.

[0092] Furthermore, as another embodiment, the first ink recovery purge valve 641 may be opened to connect the first recovery side pressure supply path P12 with the purge pressure supply path P03. In this case, the purge pressure also acts on the first upstream ink jet head 41A and the first downstream ink jet head 41B through the first recovery sub-tank 71B, so that the purge pressure can act on the ink jet head from both the supply side and the recovery side.

[0093] like Figure 4 As shown, the inkjet printer 1 according to the present embodiment is provided with a pressure measuring device 1S. The pressure measuring device 1S is capable of measuring the pressure of a plurality of pressure transmission paths for applying pressure to an object via gas (air). In the present embodiment, the object is a liquid, in particular, ink, that contacts the gas ejected from the end of the pressure transmission path. The pressure measuring device 1S includes a pressure measuring unit and a switching unit. Figure 4 When the first supply side pressure supply path P11 to the eighth supply side pressure supply path P81 (multiple pressure transmission paths), the pressure measuring unit includes: a first pressure measurement path M01 (measurement path) having an internal space capable of receiving the gas; a first pressure sensor 611 (pressure sensor) for detecting the pressure of the internal space. In addition, the switching unit has 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. In addition, Figure 4 The second pressure sensor 612 , the second pressure measurement path M02 , and the ink recovery measurement valve 65 , and the third pressure sensor 613 , the third pressure measurement path M03 , and the processing liquid measurement valve 67 also constitute the pressure measurement device 1S in the same manner.

[0094] According to such a pressure measuring device 1S, the pressure of the pressure transmission path can be measured by the pressure sensors whose number is less than the number of the pressure transmission paths. In addition, a given pressure can be easily and stably applied to the ink in the sub-tank 7. Moreover, since the pressure is transmitted via the gas in each path, even if the liquids (ink, pre-treatment liquid, post-treatment liquid) contained in each sub-tank 7 are different, the possibility of mixing these liquids can be reduced.

[0095] Moreover, in the present embodiment, the pressure measuring device 1S is mounted on the inkjet printer 1. The inkjet printer 1 has an inkjet head 4 (liquid ejection unit) that ejects ink onto a workpiece W (recording material). Furthermore, the pressure supply paths represented by the first supply side pressure supply path P11 and the first recovery side pressure supply path P12 apply the pressure to the liquid supplied to the inkjet head 4, the pre-treatment liquid ejection head 5, and the post-treatment liquid ejection head 6, or to the liquid recovered from these heads. Therefore, the pressure can be stably applied to the ink in the inkjet head 4, and the pressure can be efficiently measured.

[0096] Furthermore, in the present 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 from the compressor 50 (gas pressure source) arranged outside the carriage 3 via air. 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 in the first main regulator 53. In this way, since the compressor 50 is arranged outside the carriage 3, it is not easy to generate pressure fluctuations caused by the movement of the carriage 3, so that pressure can be stably applied to each head and each sub-tank 7.

[0097] Alternatively, the first main regulator 53 may receive pressure from a pump (gas pressure source) not shown mounted on the carriage 3 instead of the compressor 50 . In this case, the pressure transmission paths for the respective nozzles can be centrally arranged in the carriage 3 .

[0098] and, Figure 3The first upstream ink jet head 41A, the first downstream ink jet head 41B, the first supply sub-tank 71A and the first recovery sub-tank 71B constitute the liquid ejection portion of the present disclosure. The first upstream ink jet head 41A and the first downstream ink jet head 41B eject yellow ink to the workpiece W. The first supply sub-tank 71A (supply sub-tank) includes a supply tank ink area SB (first liquid area) and a supply tank gas area SA (first gas area) inside, and supplies yellow ink to the first upstream ink jet head 41A and the first downstream ink jet head 41B. In addition, the first recovery sub-tank 71B (recovery sub-tank) includes a recovery tank ink area SD (second liquid area) and a recovery tank gas area SC (second gas area) inside, and recovers yellow ink from the first upstream ink jet head 41A and the first downstream ink jet head 41B. Ink jet heads, supply sub-tanks and recovery sub-tanks corresponding to other colors also constitute the liquid ejection portion of the present disclosure in the same manner.

[0099] Moreover, 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. In addition, 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. When the inkjet printer 1 is printing, the ink supply measuring valve 63 (first switching unit) selectively switches the connection destination of the internal space (first internal space) of the first pressure measuring path M01 of the first pressure measuring unit 1A from the first supply side pressure supply path P11 to the eighth supply side pressure supply path P81 (multiple supply pressure transmission paths), so that the first pressure sensor 611 of the first pressure measuring unit 1A measures the pressure of the first internal space when the first internal space is connected to the supply tank gas area SA of one of the multiple liquid ejection units. On the other hand, the ink recovery measuring valve 65 (second switching unit) selectively switches the connection destination of the internal space (second internal space) of the second pressure measuring unit 1B from the first recovery side pressure supply path P12 to the eighth recovery side pressure supply path P82 (multiple recovery pressure transmission paths), and when the second internal space is connected to the recovery tank gas area SC of a recovery sub-tank among the multiple liquid ejection units, the second pressure sensor 612 of the second pressure measuring unit 1B measures the pressure of the second internal space.

[0100] According to such a structure, a first pressure measuring part 1A is arranged relative to a plurality of supply sub-tanks, and a second pressure measuring part 1B is arranged relative to a plurality of 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, for the purpose of ink ejection control, there is a given pressure difference between the supply side and the recovery side. In the above structure, a large pressure difference will not be generated at the respective connection destinations of the first pressure measuring path M01 and the second pressure measuring path M02, and the pressure change caused by the pressure difference will not hinder the flow of ink.

[0101] In particular, in this embodiment, as a switching unit, a dedicated ink supply measuring valve 63 is provided on the ink supply side, and a dedicated ink recovery measuring valve 65 is provided on the ink recovery side. Therefore, compared with the case where the path on the supply side and the path on the recovery side are switched separately by one switching unit, the pressure transmission path does not become complicated, and the transmission and measurement of the pressure in each path can be stably performed. In addition, in other embodiments, the path on the supply side and the path on the recovery side can also be switched separately by one switching unit as described above.

[0102] In addition, in this embodiment, if Figure 4 As shown in the figure, a method of providing a first pressure measuring unit 1A on the ink supply side and a second pressure measuring unit 1B on the ink recovery side is described, but in the case where the ejection of ink can be fully controlled by measuring and adjusting the pressure supplied to each supply sub-tank, the pressure measuring device 1S may have only the first pressure measuring unit 1A without the second pressure measuring unit 1B. Similarly, in the case where the ejection of ink can be fully controlled by measuring and adjusting the pressure supplied to each recovery sub-tank, the pressure measuring device 1S may have only the second pressure measuring unit 1B without the first pressure measuring unit 1A. In this case, the number of pressure sensors and the cost associated therewith can be reduced, and the pressure of each pressure transmission path can be stably measured.

[0103] Furthermore, in this embodiment, Figure 4The first main regulator 53 and the second main regulator 54 function as the pressure receiving section of the present disclosure. Then, the ink supply measuring valve 63 switches the connection destination of the internal space of the first pressure measuring path M01 of the first pressure measuring section 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, so that the supply tank gas area SA of the first supply sub-tank 71A is connected to the first main regulator 53. Similarly, the ink recovery measuring valve 65 switches the connection destination of the internal space of the second pressure measuring path M02 of the second pressure measuring section 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, so that the recovery tank gas area SC of the first recovery sub-tank 71B is connected to the second main regulator 54. In this state, the first pressure sensor 611 and the second pressure sensor 612 measure the pressure of the first pressure measurement path M01 and the second pressure measurement path M02, and adjust the opening of the first ink supply regulator 551 and the first ink recovery regulator 561 as needed, thereby adjusting the pressure acting on the first supply sub-tank 71A and the first recovery sub-tank 71B.

[0104] According to such a structure, the first pressure measurement path M01 is connected to the supply tank gas area SA of the first supply sub-tank 71A and the first ink supply regulator 551, respectively, so that the pressure of the entire system for supplying ink can be comprehensively measured, so that the pressure acting on the ink in the first supply sub-tank 71A can be accurately grasped. The second pressure measurement path M02 is similar.

[0105] In addition, the first pressure sensor 611 and the second pressure sensor 612 may also measure the pressures of the first supply sub-tank 71A and the first recovery sub-tank 71B at the same time. That is, the first pressure sensor 611 of the first pressure measuring unit 1A may measure the pressure of the first internal space when the first ink supply measuring valve 631 of the ink supply measuring valve 63 connects the first pressure measuring path M01 (first internal space) of the first pressure measuring unit 1A to the first supply side pressure supply path P11 and the first internal space is connected to the supply tank gas area SA of the first supply sub-tank 71A, and the first pressure sensor 612 of the second pressure measuring unit 1B may measure the pressure of the second internal space when the first ink recovery measuring valve 651 of the ink recovery measuring valve 65 connects the second pressure measuring path M02 (second internal space) of the second pressure measuring unit 1B to the first recovery side pressure supply path P12 and the second internal space is connected to the recovery tank gas area SC of the first recovery sub-tank 71B.

[0106] According to such a configuration, since the pressure on the supply side and the pressure on the recovery side are measured simultaneously for the same liquid ejection portion, it is possible to improve effective measurement accuracy.

[0107] In addition, Figure 4 In the embodiment, the volume of the first pressure measurement path M01 of the first pressure measurement unit 1A is preferably set to be less than the volume of the first supply sub-tank 71A, and more preferably set to be less than 0.5 times the volume of the first supply sub-tank 71A. According to such a structure, the pressure of the first pressure measurement path M01 is measured by the first pressure sensor 611, and the pressure of the first supply sub-tank 71A can be measured with high accuracy.

[0108] In addition, the volume of the first pressure measurement path M01 of the first pressure measurement unit 1A is more preferably set to be less than the volume of the supply tank gas area SA of the first supply sub-tank 71A, and is further preferably set to be less than 0.5 times the volume of the supply tank gas area SA. According to such a structure, the pressure of the first pressure measurement path M01 is measured by the first pressure sensor 611, and the pressure of the first supply sub-tank 71A can be measured with higher accuracy.

[0109] Similarly, in Figure 4 In the embodiment, the volume of the second pressure measuring path M02 of the second pressure measuring unit 1B is preferably set to be less than the volume of the first recovery sub-tank 71B, and is further preferably set to be less than 0.5 times the volume of the first recovery sub-tank 71B. According to such a structure, the pressure of the second pressure measuring path M02 is measured by the second pressure sensor 612, and the pressure of the first recovery sub-tank 71B can be measured with high accuracy.

[0110] In addition, the volume of the second pressure measurement path M02 of the second pressure measurement unit 1B is more preferably set to be less than the volume of the recovery tank gas area SC of the first recovery sub-tank 71B, and further set to be less than 0.5 times the volume of the recovery tank gas area SC. According to such a structure, the pressure of the second pressure measurement path M02 is measured by the second pressure sensor 612, and the pressure of the first recovery sub-tank 71B can be measured with higher accuracy.

[0111] In particular, in the case of having the volume relationship as described above, when the pressure measuring path is switched using the ink supply measuring valve 63 or the ink recovery measuring valve 65, the pressure difference between the sub-tank 7 connected to the first pressure measuring path M01 or the second pressure measuring path M02 just before the switching and the sub-tank 7 connected to the first pressure measuring path M01 or the second pressure measuring path M02 just after the switching can be utilized to make it difficult for each head or the sub-tank 7 to produce pressure changes.

[0112] In addition, in this embodiment, if Figure 2 , Figure 4 As shown, the pressures of the pressure transmission paths connected to the ink jet head 4 (ink ejection unit), the pre-treatment liquid jet head 5 (pre-treatment liquid ejection unit), and the post-treatment liquid jet head 6 (post-treatment liquid ejection unit) can be measured with high accuracy by the first pressure measuring unit 1A, the second pressure measuring unit 1B, and the third pressure measuring unit 1C. Therefore, the landing amounts of the pre-treatment liquid, the ink, and the post-treatment liquid that land on the workpiece W in sequence can be stably controlled.

[0113] In addition, a filter may be arranged between the supply tank gas area SA of the first supply sub-tank 71A in the first supply side pressure supply path P11 and the first pressure measurement path M01 of the first pressure measuring part 1A. In this case, the possibility of mixing of ink and pretreatment liquid can be reduced. When the mist-like ink and pretreatment liquid enter the first pressure measuring part 1A and mix, it is possible that a part of the components of the ink is thickened or agglomerated by the pretreatment liquid so as to adhere or stick to the first pressure measuring part 1A. Such a phenomenon may reduce the measurement accuracy or cause poor measurement operation. By configuring a filter, mist larger than the opening of the filter can be prevented from intruding, and mist smaller than the opening of the filter can also hit the parts other than the opening of the filter, so it is difficult to intrude. For the same reason, a filter may also be arranged between the recovery tank gas area SC of the first recovery sub-tank 71B in the first recovery side pressure supply path P12 and the second pressure measurement path M02 of the second pressure measuring part 1B. In addition, the same is true for other sub-tanks 7.

[0114] In addition, in this embodiment, if Figure 4 As shown, it is described in a manner that the first pressure measuring unit 1A specifically measures the pressure of the pressure transmission path of the supply system, and the second pressure measuring unit 1B specifically measures the pressure of the pressure transmission path of the recovery system. However, in other embodiments, the switching unit (valve) not shown in the figure may selectively switch the connection destination of the first pressure measuring path M01 of the first pressure measuring unit 1A from the first supply side pressure supply path P11 and the first recovery side pressure supply path P12, and the first pressure sensor 611 measures the pressure of the first pressure measuring path M01 when the first pressure measuring path M01 is connected to the supply tank gas area SA of the first supply sub-tank 71A or the recovery tank gas area SC of the first recovery sub-tank 71B. In this case, the pressures of the first supply sub-tank 71A and the first recovery sub-tank 71B corresponding to the same ink color can be measured in sequence by one first pressure sensor 611. In addition, in order to be able to cope with the pressure difference between the first supply sub-tank 71A and the first recovery sub-tank 71B, it is preferred to set the pressure resistance performance of the first pressure sensor 611 to be high. In this embodiment, Figure 4The third pressure sensor 613 in the embodiment can sequentially measure the pressures of the supply sub-tank and the recovery sub-tank of the pre-treatment liquid and the post-treatment liquid. This is because the pressure setting values ​​of these sub-tanks are similar.

[0115] The inkjet printer 1 according to the present embodiment has the following structure. The inkjet printer 1 includes a carriage 3 and a workpiece conveying unit 20. Figure 4 As shown, the inkjet printer 1 further includes a first main regulator 53 (first pressure receiving portion) and a second main regulator 54 (second pressure receiving portion) 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 transported from the supply tank ink area SB of the first supply sub-tank 71A to the first upstream ink jet head 41A and the first downstream ink jet head 41B is ejected from each jet head, and the other portion is transported to the recovery tank ink area 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.

[0116] According to such a structure, the first ink supply regulator 551 can be used to apply a desired pressure to the supply tank ink area SB (ink layer) of the first supply sub-tank 71A. Similarly, the second ink supply regulator 552 can be used to apply a desired pressure to the recovery tank ink area SD of the first recovery sub-tank 71B. In addition, the ink can be supplied to and recovered from each ink jet head by the difference between the pressure applied to the supply tank ink area SB (ink layer) in the first supply sub-tank 71A and the pressure applied to the recovery tank ink area SD (ink layer) in the first recovery sub-tank 71B.

[0117] In addition, as described above, since the carriage 3 reciprocates during printing, when a structure is adopted in which pressure is applied from the outside of the carriage, the medium to which pressure is applied from the outside of the carriage will add additional pressure due to acceleration during acceleration / deceleration, so that pressure is likely to fluctuate. However, in this embodiment, since pressure is applied via gas as the medium, pressure fluctuations due to the above-mentioned acceleration are reduced.

[0118] In addition, regarding the above-mentioned structure, the pressure receiving portion illustrated in the first main regulator 53 and the second main regulator 54 may also be one. Figure 5 , Figure 6As shown, the ink is described in a manner that the ink circulates between each ink jet head, the supply sub-tank and the recovery sub-tank, but it can also be a non-circulating structure. In addition, the sub-tank can also be used only for supply. Moreover, the structure that transmits pressure from the outside of the slide 3 via gas can also be at least one of the supply side and the recovery side. In the supply side and the recovery side, the side that does not apply the above-mentioned structure can allow pressure fluctuations or have a pressure receiving portion on the slide 3.

[0119] Furthermore, in the present embodiment, a first ink supply regulator 551 (first regulating unit) for regulating the amount of gas passing therethrough is disposed in the middle of 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 by air. Furthermore, the first pressure sensor 611 measures the pressure of the first supply side pressure supply path P11 at a portion closer to the first supply sub-tank 71A side than the first ink supply regulator 551.

[0120] According to such a configuration, the pressure of the ink acting on the supply tank ink area SB via the supply tank gas area SA of the first supply sub-tank 71A can be controlled by adjusting the first ink supply regulator 551 based on the measurement result of the first pressure sensor 611. In this case, the first ink supply regulator 551 can be adjusted by adding the measurement result of the second pressure sensor 612 to the measurement result of the first pressure sensor 611.

[0121] Similarly, in the present embodiment, the first ink recovery regulator 561 (second adjustment unit) for adjusting the amount of gas passing is arranged in the middle of the first recovery side pressure supply path P12 that connects the second main regulator 54 to the recovery tank gas area SC of the first recovery sub-tank 71B and transmits pressure by air. In addition, the second pressure sensor 612 measures the pressure of the first recovery side pressure supply path P12 at a portion closer to the first recovery sub-tank 71B than the first ink recovery regulator 561.

[0122] According to such a structure, the pressure of the ink acting on the recovery tank ink area SD via the recovery tank gas area SC of the first recovery sub-tank 71B can be controlled by adjusting the first ink recovery regulator 561 based on the measurement result of the second pressure sensor 612. In this case, the first ink recovery regulator 561 can be adjusted by adding the measurement result of the first pressure sensor 611 to the measurement result of the second pressure sensor 612. The same is true for inks of other colors.

[0123] In addition, if Figure 4As shown, the adjustment parts represented by the first ink supply regulator 551 and the first ink recovery regulator 561 are not limited to being arranged outside the carriage 3, but can also be mounted on the carriage 3. When these adjustment parts are mounted on the carriage 3, the number of air pressure pipes for pressure adjustment from the main body side can be set to one regardless of the number of colors. On the other hand, when these adjustment parts are arranged outside the carriage 3, the weight of the carriage 3 can be reduced and compact.

[0124] Furthermore, the present disclosure is not limited to the above-described embodiments, and can adopt the following modes.

[0125] (1) The ink jet heads 4 are not limited to being arranged in two rows on the carriage 3. The ink jet heads 4 may be arranged in one row or in three or more rows. Furthermore, the ink jet printer 1 is not limited to being able to eject ink of multiple colors onto the workpiece W, and may eject ink of a single color.

[0126] (2) In the above embodiment, the inkjet printer 1 may not include the pre-treatment liquid head 5 for discharging the pre-treatment liquid, the post-treatment liquid head 6 for discharging the post-treatment liquid, and components related thereto. In addition, at least one of the pre-treatment liquid and the post-treatment liquid may not include a recovery tank.

[0127] (3) A plurality of structures respectively disclosed in the above-mentioned embodiments can constitute one disclosure by being combined with each other.

[0128] -Explanation of symbols-

[0129] 1 Inkjet printer (recording device)

[0130] 10. Device Framework

[0131] 100 Control Department

[0132] 1A First pressure measuring unit (pressure measuring unit)

[0133] 1B Second pressure measuring unit (pressure measuring unit)

[0134] 1C Third pressure measuring unit (pressure measuring unit)

[0135] 1S Pressure measuring device

[0136] 20 Workpiece conveying unit (conveying unit)

[0137] 3 Slide

[0138] 4 Ink nozzle (ink ejection part)

[0139] 41A First upstream ink jet head

[0140] 41B First downstream ink jet head

[0141] 5 Pretreatment liquid nozzle (pretreatment liquid spraying part)

[0142] 50 Compressor (gas pressure source)

[0143] 51 Filters

[0144] 52 Main regulator for purge

[0145] 53 First main regulator (pressure receiving part)

[0146] 54 Second main regulator (pressure receiving part)

[0147] 55 Ink supply regulator

[0148] 551 First ink supply regulator

[0149] 552 Second ink supply regulator

[0150] 56 Ink recovery regulator

[0151] 561 First ink recovery regulator

[0152] 562 Second ink recovery regulator

[0153] 6 Post-treatment liquid nozzle (post-treatment liquid spraying part)

[0154] 611 First pressure sensor

[0155] 612 Second pressure sensor

[0156] 613 Third pressure sensor

[0157] 62 Ink supply purge valve

[0158] 621 First ink supply purge valve

[0159] 622 Second ink supply purge valve

[0160] 63 ink supply measuring valve (switching unit, first switching unit)

[0161] 631 First ink supply measurement valve

[0162] 632 Second ink supply measurement valve

[0163] 64 Ink recovery purge valve

[0164] 641 First ink recovery purge valve

[0165] 642 Second ink recovery purge valve

[0166] 65 ink recovery measuring valve (switching unit, second switching unit)

[0167] 651 First ink recovery measurement valve

[0168] 652 Second ink recovery measurement valve

[0169] 7 Auxiliary tank

[0170] 71A First supply sub-tank (supply sub-tank)

[0171] 71A1, 71B1 Capacitive Sensor

[0172] 71B First recovery tank (recovery tank)

[0173] 72A Second supply sub-tank (supply sub-tank)

[0174] 72B Second recovery tank (recovery tank)

[0175] M01 First pressure measurement path (internal space, first internal space)

[0176] M02 Second pressure measurement path (internal space, second internal space)

[0177] M03 Third pressure measurement path

[0178] P01 1st main pressure supply line

[0179] P02 Second main pressure supply line

[0180] P03 Purge pressure supply line

[0181] P11 First supply side pressure supply path (pressure transmission path, supply pressure transmission path)

[0182] P12 First recovery side pressure supply path (pressure transmission path, recovery pressure transmission path)

[0183] P21 Second supply side pressure supply path (pressure transmission path, supply pressure transmission path)

[0184] P22 Second recovery side pressure supply path (pressure transmission path, recovery pressure transmission path)

[0185] SA Supply tank gas area

[0186] SB Supply Tank Ink Area

[0187] SC Recovery Tank Gas Area

[0188] SD recovery tank ink area

[0189] W workpiece.

Claims

1. A pressure measuring device for measuring pressures of a plurality of pressure transmission paths for applying pressure to an object via a gas, comprising: at least one pressure measuring unit including a measuring path having an internal space capable of receiving the gas and a pressure sensor for detecting the pressure of the internal space; and At least one switching unit can selectively switch a connection destination of the measurement path from among the plurality of pressure transmission paths.

2. The pressure measuring device according to claim 1, wherein: The object is a liquid that comes into contact with the gas ejected from the end of the pressure transmission path.

3. A recording device comprising: The pressure measuring device according to claim 2; the plurality of pressure transmission paths; and at least one liquid ejecting unit ejects liquid onto the recording material, The plurality of pressure transmission paths respectively apply the pressure to the liquid supplied to the at least one liquid ejection portion or the liquid recovered from the at least one liquid ejection portion.

4. The recording device according to claim 3, wherein: The apparatus further comprises: a carriage that supports the at least one liquid ejecting unit and reciprocates in a main scanning direction, The plurality of pressure transmission paths receive pressure from a gas pressure source disposed outside the carriage via the gas.

5. The recording device according to claim 3, wherein: The apparatus further comprises: a carriage that supports the at least one liquid ejecting unit and reciprocates in a main scanning direction, The plurality of pressure transmission paths receive pressure from a gas pressure source mounted on the carriage via the gas.

6. The recording device according to claim 3, wherein: The at least one liquid ejection unit has a plurality of liquid ejection units, each of which includes: a liquid ejection head for ejecting liquid to the recording material; a supply sub-tank, which includes a first liquid area and a first gas area inside, and supplies the liquid to the liquid ejection head; and a recovery sub-tank, which includes a second liquid area and a second gas area inside, 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 parts; and a plurality of recovery pressure transmission paths respectively connected to the second gas regions of the recovery sub-tanks of the plurality of liquid ejection units, The at least one pressure measuring unit includes a first pressure measuring unit and a second pressure measuring unit, The at least one switching unit selectively switches the connection destination of the internal space of the first pressure measuring unit, i.e., the first internal space, from the plurality of supply pressure transmission paths, and the pressure sensor of the first pressure measuring unit measures the pressure of the first internal space in a state where the first internal space is connected to the first gas region of one of the supply sub-tanks of the plurality of liquid ejecting units. The at least one switching unit selectively switches the connection destination of the internal space of the second pressure measuring unit, i.e., the second internal space, from the multiple recovery pressure transmission paths, and when the second internal space is connected to the second gas region of one of the recovery sub-tanks among the multiple liquid ejection units, the pressure sensor of the second pressure measuring unit measures the pressure of the second internal space.

7. The recording device according to claim 6, wherein: The at least one switching unit includes a first switching unit and a second switching unit, The first switching unit selectively switches a connection destination of the first internal space of the first pressure measuring unit from among the plurality of supply pressure transmission paths, and the pressure sensor of the first pressure measuring unit measures the pressure of the first internal space in a state where the first internal space is connected to the first gas region of one of the supply sub-tanks of the plurality of liquid ejecting units. The second switching unit selectively switches the connection destination of the second internal space of the second pressure measuring unit from the multiple recovery pressure transmission paths, and when the second internal space is connected to the second gas area of ​​one of the recovery sub-tanks among the multiple liquid ejection units, the pressure sensor of the second pressure measuring unit measures the pressure of the second internal space.

8. The recording device according to claim 3, wherein: The at least one liquid ejection unit includes a plurality of liquid ejection units, each of which includes: a liquid ejection head for ejecting liquid to the recording material; and a supply sub-tank including a first liquid area and a first gas area therein for supplying 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. The at least one switching unit selectively switches the connection destination of the internal space of the at least one pressure measuring unit from the multiple supply pressure transmission paths, and the pressure sensor measures the pressure of the internal space when the internal space is connected to the first gas area of ​​one of the supply sub-tanks among the multiple liquid ejection units.

9. The recording device according to claim 3, wherein: The at least one liquid ejection unit includes a plurality of liquid ejection units, each of which includes a liquid ejection head for ejecting liquid to the recording material; and a recovery sub-tank including a second liquid area and a second gas area therein for recovering 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. The at least one switching unit selectively switches the connection destination of the internal space of the at least one pressure measuring unit from the multiple recovery pressure transmission paths, and the pressure sensor measures the pressure of the internal space when the internal space is connected to the second gas region of one of the recovery sub-tanks among the multiple liquid ejection units.

10. The recording device according to claim 3, wherein: The at least one liquid ejection unit includes: a liquid ejection head for ejecting liquid to the recording material; a supply sub-tank including a first liquid area and a first gas area inside and supplying the liquid to the liquid ejection head; and a recovery sub-tank including a second liquid area and a second gas area inside and recovering 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 portion; and 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, The at least one switching unit selectively switches the connection destination of the internal space of the at least one pressure measuring unit from the at least one supply pressure transmission path and the at least one recovery pressure transmission path, and the pressure sensor measures the pressure of the internal space when the internal space is connected to the first gas area of ​​the supply sub-tank or the second gas area of ​​the recovery sub-tank of the at least one liquid ejection unit.

11. The recording device according to claim 6, wherein: The plurality of pressure transmission paths each include 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 measuring unit from among the plurality of supply pressure transmission paths, and the pressure sensor of the first pressure measuring unit measures the pressure of the first internal space in a state where the first internal space is connected to the first gas region of one of the supply sub-tanks of the plurality of liquid ejection units and the pressure receiving unit. The at least one switching unit selectively switches the connection destination of the second internal space of the second pressure measuring unit from the multiple recovery pressure transmission paths, and when the second internal space is connected to the second gas area of ​​one of the recovery sub-tank among the multiple liquid ejection units and the pressure receiving unit, the pressure sensor of the second pressure measuring unit measures the pressure of the second internal space.

12. The recording device according to claim 3, wherein: The at least one liquid ejection unit comprises: a liquid ejection head for ejecting liquid to the recording material; a supply sub-tank including a first liquid region and a first gas region therein for supplying the liquid to the liquid ejection head; and a recovery sub-tank including a second liquid region and a second gas region therein for recovering 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; and a recovery pressure transmission path communicating with the second gas region of the recovery sub-tank, The at least one pressure measuring unit includes a first pressure measuring unit and a second pressure measuring unit, The at least one switching unit connects the internal space of the first pressure measuring unit, i.e., the first internal space, to the supply pressure transmission path. When the first internal space is connected to the first gas region of the supply sub-tank, the pressure sensor of the first pressure measuring unit measures the pressure of the first internal space. The at least one switching unit connects the internal space of the second pressure measuring unit, i.e., the second internal space, to the recovery pressure transmission path. When the second internal space is connected to the second gas region of the recovery sub-tank, the pressure sensor of the second pressure measuring unit measures the pressure of the second internal space while measuring the pressure of the first internal space.

13. The recording device according to claim 6, wherein: The volume of the first internal space of the first pressure measuring section is set to be less than or equal to the volume of the supply sub-tank.

14. The recording device according to claim 6, wherein: The volume of the second internal space of the second pressure measuring section is set to be less than or equal to the volume of the sub-tank for recovery.

15. The recording device according to claim 6, wherein: The volume of the first internal space of the first pressure measuring unit is set to be less than or equal to the volume of the first gas region of the supply sub-tank.

16. The recording device according to claim 6, wherein: The volume of the second internal space of the second pressure measuring unit is set to be less than or equal to the volume of the second gas region of the recovery sub-tank.

17. The recording device according to claim 6, wherein: The at least one liquid ejection portion comprises: An ink ejection unit ejects ink as the liquid; A pretreatment liquid spraying part sprays the pretreatment liquid as the liquid; as well as The post-processing liquid ejecting portion ejects the post-processing liquid as the liquid.

18. The recording device according to claim 6, wherein: The system further includes a filter disposed between the first gas region of the supply sub-tank and the first internal space of the first pressure measuring unit in the supply pressure transmission path.

19. The recording device according to claim 6, wherein: The system further includes a filter disposed between the second gas region of the recovery sub-tank and the second internal space of the second pressure measuring unit in the recovery pressure transmission path.

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