Pressure adjustment device, and printer

Abstract

To provide a pressure adjustment device which has such a mechanism as to circulate a liquid between two tanks by generating a differential pressure between the two tanks, and can detect leakage of the liquid from the two tanks in the mechanism.SOLUTION: A pressure adjustment device includes: a first supply tank and a first recovery tank which are fluid-connected to a first inkjet head; a second supply tank and a second recovery tank which are fluid-connected to a second inkjet head; first and second supply side air flow channels which are respectively fluid-connected to the first and second supply tanks; a first sensor assembly which is fluid-connected to the first and second supply side air flow channels; a first air regulator which is fluid-connected to the first sensor assembly; first and second recovery side air flow channels which are respectively fluid-connected to the first and second recovery tanks; a second sensor assembly which is fluid-connected to the first and second recovery side air flow channels; and a second air regulator which is fluid-connected to the second sensor assembly.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a pressure adjusting device and a printing device equipped with the pressure adjusting device. [Background technology]

[0002] Conventionally, there is known an inkjet printing device that includes an inkjet head, a pressurized tank that stores ink to be supplied to the inkjet head, a negative pressure tank that stores ink returned from the inkjet head, a circulation path for circulating ink from the pressurized tank to the negative pressure tank via the inkjet head, and an ink pump that sends ink from the negative pressure tank to the pressurized tank. This inkjet printing device further includes a pressurized air chamber that communicates with an air layer of the pressurized tank, and a negative pressure air chamber that communicates with an air layer of the negative pressure tank. The pressurized air chamber is communicated with a pressurized pump and a pressurized side pressure sensor. The pressurized pump adjusts the pressure of the air layer of the pressurized tank via the pressurized air chamber. The pressurized side pressure sensor detects the pressure in the pressurized air chamber. The negative pressure air chamber is communicated with a negative pressure pump and a negative pressure side pressure sensor. The negative pressure pump adjusts the pressure of the air layer of the negative pressure tank via the negative pressure air chamber. The negative pressure side pressure sensor detects the pressure in the negative pressure air chamber (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-068327 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the inkjet printing device described in Patent Document 1, for example, if the balance between the pressure of the air space of the pressurized tank and the pressure of the air space of the negative pressure tank is lost, the ink in the pressurized tank may flow into the pressurized air chamber, or the ink in the negative pressure tank may flow into the negative pressure air chamber. However, the pressurized side pressure sensor detects the pressure of the air in the pressurized air chamber, and cannot detect the ink that has flowed into the pressurized air chamber. Similarly, the negative pressure side pressure sensor detects the pressure of the air in the negative pressure air chamber, and cannot detect the ink that has flowed into the negative pressure air chamber. If the ink in the pressurized tank passes through the pressurized air chamber and flows into the pressurized pump without being detected by the pressurized side pressure sensor, this may cause the pressurized pump to break down. Also, if the ink in the negative pressure tank passes through the negative pressure air chamber and flows into the negative pressure pump without being detected by the negative pressure side pressure sensor, this may cause the negative pressure pump to break down.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a pressure adjustment device that has a mechanism for circulating liquid between two tanks by generating a pressure difference between the two tanks, and that is capable of detecting leakage of liquid from the two tanks using the mechanism, and a printing device that is equipped with the pressure adjustment device. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided a first ink-jet head having a circulation flow path connecting a first supply port and a first recovery port, the first supply tank being fluidly connected to the first supply port, and a first recovery tank being fluidly connected to the first recovery port; a second inkjet head having a circulation flow path connecting a second supply port and a second recovery port, the second inkjet head including a second supply tank fluidly connected to the second supply port and a second recovery tank fluidly connected to the second recovery port; a first supply air flow passage fluidly connected to the first supply tank and a second supply air flow passage fluidly connected to the second supply tank; a first sensor assembly fluidly connected to the first supply air flow path and the second supply air flow path; a first air regulator fluidly connected to the first sensor assembly; a first recovery air flow passage fluidly connected to the first recovery tank, and a second recovery air flow passage fluidly connected to the second recovery tank; a second sensor assembly fluidly connected to the first return air flow path and the second return air flow path; a second air regulator fluidly connected to the second sensor assembly; the first sensor assembly includes a first sensor configured to detect the presence or absence of a first liquid within the first sensor assembly; A pressure regulating apparatus is provided, wherein the second sensor assembly includes a second sensor for detecting the presence or absence of a second liquid within the second sensor assembly.

[0007] According to a second aspect of the present invention, there is provided a pressure regulating device according to the first aspect, A printing apparatus is provided that includes a transport device that transports a medium relative to the first inkjet head and the second inkjet head. Effect of the Invention

[0008] According to the first and second aspects of the present invention, there is provided a pressure adjustment device that includes a mechanism for causing a pressure difference between two ink tanks to cause ink to flow between the two ink tanks, and that is capable of detecting ink leakage from the two ink tanks in the mechanism, and a printing device that includes the pressure adjustment device. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a printer 1000 according to an embodiment. [Diagram 2] FIG. 1 is a perspective view of a head system 100. [Diagram 3] FIG. 2 is an exploded perspective view of the subtank 20. [Figure 4] FIG. [Diagram 5] FIG. 2 is a perspective view of the head mechanism 40. [Figure 6] FIG. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] 1A and 1B are diagrams for explaining the flow path configuration of an HPM (Hydraulic Pneumatics Module) 500, and the connections between a first air regulator AR1, a second air regulator AR2, a first sensor assembly SA1, a second sensor assembly SA2, and a head system 100. [Figure 9] 1A is a perspective view of the first sensor assembly SA1, and FIG. 1B is a vertical sectional view of the first sensor assembly SA1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a printer (printing device) 1000 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9(b).

[0011] <Printer 1000> As shown in FIG. 1, the printer 1000 mainly comprises six head systems 100, a platen 200, two conveying rollers 301, 302, six ink tanks 400, a first air regulator AR1, a first sensor assembly SA1, a second air regulator AR2, a second sensor assembly SA2, a controller 700, and a housing 900 that houses these.

[0012] In the printer 1000, the direction in which the two transport rollers 301 and 302 are aligned, i.e., the direction in which the medium PM is transported during image formation, is referred to as the "transport direction." Additionally, the direction that extends in the horizontal plane and is perpendicular to the transport direction is referred to as the "medium width direction."

[0013] Each of the six head systems 100 is a so-called line-type head (head bar), and is supported by a frame 100a at both ends in the medium width direction. The specific structure and function of the head system 100 will be described later.

[0014] The frame 100a supports the six head systems 100 with their front-to-rear directions (described later) aligned with the transport direction of the printer 1000 and with their nozzle surfaces 40n (described later) facing the upper surface of a platen 200.

[0015] The platen 200 is a plate-like member that supports the medium PM from the side opposite the head systems 100 (below) when ink is ejected from the six head systems 100 toward the medium PM.

[0016] The two transport rollers 301, 302 are positioned to sandwich the platen 200 in the transport direction. The two transport rollers 301, 302 function as a transport device that sends the medium PM in a predetermined manner in the transport direction when the six head systems 100 form an image on the medium PM.

[0017] Each of the six ink tanks 400 is connected to one of the six head systems 100 by a hydraulic pneumatics module (HPM) 500 (see FIG. 8).

[0018] One HPM 500 is provided to connect one ink tank 400 and one head system 100. In other words, the printer 1000 has a total of six HPMs 500. The specific structure and function of the HPM 500 will be described later.

[0019] In this embodiment, six different types of ink are stored in the six ink tanks 400, and each of the six head systems 100 ejects one of the six different types of ink. The six types of ink are, for example, black ink, cyan ink, light cyan ink, magenta ink, light magenta ink, and yellow ink.

[0020] The first air regulator AR1 is fluidly connected to the six head systems 100 via a conduit T1, a first sensor assembly SA1, and six supply-side air flow paths AT1. The second air regulator AR2 is fluidly connected to the six head systems 100 via a conduit T2, a second sensor assembly SA2, and six recovery-side air flow paths AT2. The first air regulator AR1 and the second air regulator AR2 are, for example, electro-pneumatic regulators, and circulate ink within each head system 100 by generating a pressure difference in each head system 100. The specific structures and functions of the first sensor assembly SA1 and the second sensor assembly SA2 will be described later.

[0021] The controller 700 controls each unit of the printer 1000 as a whole, causing each unit to perform operations such as forming an image on the medium PM. The controller 700 includes an FPGA (Field Programmable Gate Array), an EEPROM (Electrically Eracable Programmable Read-Only Memory, registered trademark), a RAM (Random Access Memory), and the like. The controller 700 may also include a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and the like. The controller 700 is connected to an external device EA such as a PC so as to be able to perform data communications, and controls each unit of the printer 1000 based on print data sent from the external device EA.

[0022] <Head System 100> 2, each of the six head systems 100 mainly includes a housing 10, a subtank 20, ten head mechanisms 40 arranged in a staggered pattern, a relay board 50, and a control board unit 60. Since the six head systems 100 have the same configuration, the following description focuses on one of the six head systems 100.

[0023] In the following description, the direction in which the ten head mechanisms 40 are arranged in a staggered (zigzag) pattern is referred to as the width direction of the head system 100, and the direction in which the ten head mechanisms 40 and the subtanks 20 are arranged is referred to as the up-down direction. In addition, the direction perpendicular to the width direction and up-down direction is referred to as the front-rear direction of the head system 100.

[0024] 2 are defined as the front and rear sides in the front-to-rear direction. Regarding the width direction, the left and right sides when viewed from the front in the front-to-rear direction are defined as the left and right sides in the width direction. Regarding the up-down direction, the side where the sub-tanks 20 are located with respect to the ten head mechanisms 40 is defined as the upper side, and the opposite side is defined as the lower side.

[0025] When the head system 100 is mounted on the printer 1000 , the width direction of the head system 100 coincides with the medium width direction of the printer 1000 , and the front-rear direction of the head system 100 coincides with the transport direction of the printer 1000 .

[0026] <Case 10> The housing 10 may be made of, for example, metal. The housing 10 includes a first housing 11 and a second housing 12 that is detachable from the first housing 11.

[0027] The first housing 11 has a top plate, a bottom portion, a front wall (not shown in FIG. 2 in order to show the interior of the first housing 11), a rear wall, a left wall, and a right wall. Inside the first housing 11, a space is defined that is surrounded by the top plate, the bottom portion, the front wall, the rear wall, the left wall, and the right wall.

[0028] The top plate of the first housing 11 has a first area extending to the right from the upper end of the left wall of the first housing 11, a vertical area extending downward from the right end of the first area, and a second area extending to the right from the lower end of the vertical area to the upper end of the right wall of the first housing 11.

[0029] The left wall of the first housing 11 has two air vents AP aligned in the front-rear direction. 10 and two ink flow ports IP aligned in the front-back direction. 10 Two ink flow ports IP 10 AP has two air vents10 Located below.

[0030] 2, the second housing 12 has a top plate, a bottom plate, a front wall, a rear wall, a left wall, and a right wall. When the second housing 12 is attached to the first housing 11, the bottom plate of the second housing 12 abuts against a second region of the top plate of the first housing 11.

[0031] <Subtank 20> The subtank 20 stores the ink supplied from the ink tank 400 to the head system 100. The ink stored in the subtank 20 is distributed to the ten head mechanisms 40.

[0032] 2, the sub-tank 20 has an elongated shape. The sub-tank 20 is positioned in the space within the first housing 11 with its longitudinal direction coinciding with the width direction of the head system 100.

[0033] 3 and 4, the subtank 20 is composed of a main body 21, a top plate 22, and a bottom plate 23. As shown in Fig. 4, a sheet heater 24 is attached to the lower surface of the bottom plate 23.

[0034] The main body 21 is formed of resin, for example. The main body 21 has a front wall 21c and a rear wall 21d extending along a plane perpendicular to the front-rear direction of the head system 100, and a left wall 21e and a right wall 21f extending along a plane perpendicular to the width direction of the head system 100. Inside the main body 21, a separation wall 21w is located which is parallel to the front wall 21c and the rear wall 21d.

[0035] The top plate 22 is, for example, a flat plate made of metal. The shape of the top plate 22 in a plan view is the same as the outline shape of the main body 21 when viewed from above. The top plate 22 is fixed to the upper end of the main body 21 with a seal rubber (not shown) sandwiched therebetween.

[0036] The bottom plate 23 is a flat plate made of metal. The shape of the bottom plate 23 in a plan view is the same as the outline shape of the main body 21 when viewed from above. The bottom plate 23 is fixed to the lower end of the main body 21 with a seal rubber (not shown) sandwiched therebetween.

[0037] 3, in the subtank 20, a fill tank FT is formed by the front wall 21c, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. A drain tank DT is formed by the rear wall 21d, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The internal space IN of the fill tank FT FT and the internal space of the drain tank DT IN DT The sub-tank 20 is a closed space and is separated from the internal space IN of the fill tank FT. FT A liquid level sensor (not shown) detects the liquid level of the ink contained in the drain tank DT. DT and a liquid level sensor (not shown) that detects the liquid level of the ink contained in the ink container.

[0038] The left wall 21e has two ink flow ports IP 20 are arranged in the front-rear direction. 20 The internal space of the fill tank FT IN FT The ink flow port IP at the rear 20 is the internal space of the drain tank DT DT It is connected to.

[0039] The top plate 22 has two air vents AP 20 The front air vents AP are aligned in the front-rear direction. 20 The internal space of the fill tank FT FT The rear air vent AP 20 is the internal space of the drain tank DT DT In addition, the front air vent AP 20 The air flow opening AP 1 at the front of the first housing 11 is connected to the supply side air flow passage AT1, which will be described later. 10The rear air outlet AP is fluidly connected to the 20 The air flow port AP 11 is connected to the rear of the first housing 11 by a single recovery air flow path AT2 (described later). 10 is in fluid communication with

[0040] As shown in Fig. 4, ten ink circulation port sets S are formed on the lower surface of the bottom plate 23. Each of the ink circulation port sets S includes one ink supply port SP and one ink recovery port DP. The ten ink circulation port sets S are arranged in a staggered (zigzag) pattern along the width direction of the head system 100. In each ink circulation port set S, the ink supply port SP and the ink recovery port DP are aligned in the width direction.

[0041] A flow path (not shown) formed in the lower part of the inside of the main body 21 allows the internal space IN of the fill tank FT to flow through the FT are connected to the ink supply ports SP of each ink circulation port set S, and the internal space IN of the drain tank DT DT are in communication with the ink recovery ports DP of each ink circulation port set S.

[0042] <Head mechanism 40> Each of the ten head mechanisms 40 has the same configuration. The configuration of one head mechanism 40 will be described below. As shown in Fig. 5, the head mechanism 40 has, in order from the top, a connection plate 41, a main body 42, and a head 43. The head mechanism 40 further has a wiring connection part WC that extends in the vertical direction between the upper part of the connection plate 41 and the head 43.

[0043] The connection plate 41 is formed with an ink supply port ISP and an ink recovery port IDP.

[0044] The main body 42 is fixed to the lower surface of the connection plate 41. Inside the main body 42, a supply branch flow path (not shown) for supplying ink supplied to the ink supply port ISP to the head 43, and a recovery branch flow path (not shown) for returning ink not ejected from the head 43 to the ink recovery port IDP are formed.

[0045] The head 43 is fixed to the lower surface of the main body 42. The head 43 includes a flow path unit 431 and a piezoelectric actuator 432 (see FIGS. 6 and 7).

[0046] 7, the flow path unit 431 is a laminated structure in which an ink sealing film 431A, plates 431B to 431E, and a nozzle plate 431F are laminated in this order from above. As shown in FIG. 6, a flow path CH is formed inside the flow path unit 431.

[0047] The flow channel CH has eight ink flow ports IP 43 Each of the four manifold channels M1 to M4 is a linear channel extending in the left-right direction, and has an ink flow port IP 43 Each of the four manifold channels M1 to M4 is connected to 12 individual channels iCH.

[0048] As shown in FIG. 7, each of the individual channels iCH includes a pressure chamber 1, a descender channel 2, and a nozzle 3. The upper surface of the pressure chamber 1 is formed by an ink sealing film 431A. The descender channel 2 extends in the vertical direction from the pressure chamber 1 toward the nozzle 3. The nozzle 3 is a minute opening that ejects ink toward the medium PM, and is formed in the nozzle plate 431F. The lower surface of the nozzle plate 431F is the lower surface of the head mechanism 40, and is the nozzle surface 40n. As shown in FIG. 6, the nozzle surface 40n has four nozzle rows L aligned in the front-rear direction. 3 Each nozzle row L 3 is formed by twelve nozzles 3 aligned in the left-right direction.

[0049] 7, the piezoelectric actuator 432 is composed of a first piezoelectric layer L1 located on the upper surface of the flow path unit 431, a second piezoelectric layer L2 above the first piezoelectric layer L1, a common electrode cET sandwiched between the first piezoelectric layer L1 and the second piezoelectric layer L2, and a plurality of individual electrodes iET located on the upper surface of the second piezoelectric layer L2. The plurality of individual electrodes iET are respectively located above the plurality of pressure chambers 1 of the plurality of individual flow paths iCH. The portions of the second piezoelectric layer L2 sandwiched between the common electrode cET and each of the plurality of individual electrodes iET become active portions AC polarized in the thickness direction.

[0050] Each of the individual electrodes iET of the piezoelectric actuator 432 is connected to a control board 442 on which a driver IC is mounted via an FPC (Flexible Printed Circuits) 441. The control board 442 is located inside the main body .

[0051] The wiring connection part WC is in the form of a substrate. An upper end of the wiring connection part WC protrudes above the connection plate 41. The wiring connection part WC is connected to the relay board 50 (see FIG. 2) via a flexible substrate (not shown). A lower end of the wiring connection part WC is connected to the control board 442.

[0052] The ten head mechanisms 40 are fixed to the bottom of the first housing 11 (see FIG. 2). In this state, the nozzle surface 40n of each head mechanism 40 is exposed toward the bottom of the housing 10. In addition, each nozzle row L of the nozzle surface 40n 3 extends along the width direction of the head system 100. The ten head mechanisms 40 are arranged in a staggered (zigzag) pattern along the width direction.

[0053] Each of the head mechanisms 40 and the sub-tank 20 are connected by an ink tube set ITS (see FIG. 2). The ink tube set ITS includes one ink supply tube IST and one ink recovery tube IDT.

[0054] The upper end of each ink supply tube IST is connected to the ink supply port SP of each ink circulation port set S of the subtank 20. The lower end of each ink supply tube IST is connected to the ink supply port ISP of the head mechanism 40. The upper end of each ink recovery tube IDT is connected to the ink recovery port DP of each ink circulation port set S of the subtank 20. The lower end of each ink recovery tube IDT is connected to the ink recovery port IDP of the head mechanism 40. In other words, the fill tank FT of the subtank 20 is fluidly connected to the ink supply port ISP of each head mechanism 40, and the drain tank DT of the subtank 20 is fluidly connected to the ink recovery port IDP of each head mechanism 40.

[0055] In each head mechanism 40, the ink flowing from the fill tank FT of the subtank 20 to the ink supply port ISP is passed through the supply branch flow paths of the main body 42 and the four ink flow ports IP 43 The ink in the four manifolds M1 to M4 that is not ejected from the nozzles 3 flows through the remaining four ink flow ports IP 43 The ink is collected in the drain tank of the sub-tank 20 via the ink collection branch flow path of the main body 42 and the ink collection port IDP. 43 A circulation flow path within each head mechanism 40 is formed by the four manifolds M1 to M4 and the recovery branch flow path.

[0056] <Relay board 50> The relay board 50 mainly serves as a relay between a control board unit 60 (described later) and a control board 442 of the head mechanism 40. The relay board 50 is connected to the wiring connection parts WC of each of the ten head mechanisms 40 by a flexible board (not shown).

[0057] The relay board 50 is also connected to an electrical connector of the housing 10 by wiring (not shown), and distributes the power supplied from the electrical connector to the control board unit 60 and the like.

[0058] As shown in FIG. 2, the relay board 50 is attached to the underside of the second area of ​​the top plate of the first housing 11 in parallel with the second area.

[0059] <Control board unit 60> The control board unit 60 receives print data signals from the controller 700 of the printer 1000, and sends them to the control board 442 of each head mechanism 40 via the relay board 50. The control board unit 60 is provided inside the second housing 12 of the housing 10 (FIG. 2).

[0060] A terminal (not shown) of the control board unit 60 protrudes downward through an opening (not shown) provided in the bottom plate of the second housing 12. The second housing 12 is attached to and detached from the first housing 11 by attaching and detaching the terminal of the control board unit 60 to a connector (not shown) of the relay board 50 through an opening (not shown) provided in a second region of the top plate of the first housing 11.

[0061] <hpm500> As described above, each HPM 500 (see FIG. 8) connects one ink tank 400 and one head system 100. Since the six HPMs 500 have the same configuration, the following description focuses on one of the six.

[0062] As shown in FIG. 8, the HPM 500 mainly includes a pump P, a degassing unit DU, five flow paths (flow paths CH1 to CH5), and five valves (valves V1 to V5).

[0063] The flow channel CH1 connects the ink tank 400 and the suction port PA of the pump P. The flow channel CH2 connects the ink flow port IP 10 and one ink flow port IP of the subtank 20 20 The outlet PB of the pump P is connected to the fill tank FT via the ink passage CH2. The ink passage CH3 is a passage branched off from the ink passage CH2 at the branch J1. The ink passage CH3 is connected to the ink passage IP 10 and the other ink flow port IP of the subtank 20 20 The flow path CH4 is a flow path that branches off from the flow path CH1 at the branch J2 and merges with the flow path CH3. The flow path CH4 connects the branch J2 of the flow path CH1 and the branch J3 of the flow path CH3. The flow path CH5 is a flow path that branches off from the flow path CH2 at the branch J4. The flow path CH5 connects the branch J4 of the flow path CH2 and the ink tank 400.

[0064] The valve V1 is located in the flow path CH1 between the ink tank 400 and the branch J2. The valve V2 is located in the flow path CH2 between the branch J1 and the fill tank FT. The valve V3 is located in the flow path CH3 between the branches J1 and J3. The valve V4 is located in the flow path CH4. The valve V5 is located in the flow path CH5.

[0065] The degassing unit DU is located between the branch J1 and the branch J4 of the flow path CH2. The degassing unit DU of this embodiment is a known degassing module, and removes gases such as air contained in the ink passing through the degassing unit DU.

[0066] As one example, the controller 700 supplies ink only to the fill tank FT from the ink tank 400 by driving the pump P with the first valve V1 and the second valve V2 of the HPM 500 open and the third valve V3 to the fifth valve V5 closed. As another example, the controller 700 supplies ink from the ink tank 400 to both the fill tank FT and the drain tank DT by driving the pump P with the first valve V1 to the third valve V3 of the HPM 500 open and the fourth valve V4 and the fifth valve V5 closed.

[0067] On the other hand, the controller 700 recovers ink from the drain tank DT to the ink tank 400 by driving the pump P with the fourth valve V4 and the fifth valve V5 of the HPM 500 open and the first valve V1 to the third valve V3 closed.

[0068] <Pressure Regulating Device> The pressure regulating device of the present invention mainly comprises a fill tank FT and a drain tank DT provided in each head system 100, six supply side air flow paths AT1 and six recovery side air flow paths AT2, a first sensor assembly SA1 and a second sensor assembly SA2, a first air regulator AR1 and a second air regulator AR2, and a controller 700. As shown in FIG. 1, the first sensor assembly SA1 communicates with the six head systems 100 via the six supply side air flow paths AT1. The second sensor assembly SA2 communicates with the six head systems 100 via the six recovery side air flow paths AT2. More specifically, as shown in FIG. 8, the first sensor assembly SA1 communicates with the fill tank FT of one head system 100 via one of the six supply side air flow paths AT1. The second sensor assembly SA2 communicates with the drain tank DT of the one head system 100 via one of the six recovery side air flow paths AT2. In FIG. 8, only one head system 100 to which the first sensor assembly SA1 and the second sensor assembly SA2 communicate is representatively shown, and the remaining five head systems 100 are omitted from the illustration.

[0069] 8, one supply-side air flow path AT1 is fluidly connected to the fill tank FT of the head system 100, and a first sensor assembly SA1 is fluidly connected to the supply-side air flow path AT1. One recovery-side air flow path AT2 is fluidly connected to the drain tank DT of the head system 100, and a second sensor assembly SA2 is fluidly connected to the recovery-side air flow path AT2. In other words, one supply-side air flow path AT1 is connected to an air circulation port AP in front of the sub tank 20. 20 and an air circulation port AP at the front of the first housing 11 10 Through the inner space of the fill tank FT IN FT The first sensor assembly SA1 is connected to the collection air passage AT2 through the air outlet AP 20 and the air circulation port AP at the rear of the first housing 11 10 Through the drain tank DT, the internal space IN DT and the second sensor assembly SA2.

[0070] Next, the specific structures of the first sensor assembly SA1 and the second sensor assembly SA2 will be described with reference to Figures 9(a) and 9(b). Note that the first sensor assembly SA1 and the second sensor assembly SA2 have different connection destinations, but have the same structure. For this reason, Figures 9(a) and 9(b) show the first sensor assembly SA1 as a representative example.

[0071] 9(a) and 9(b), each of the first sensor assembly SA1 and the second sensor assembly SA2 mainly includes a container 600 and a sensor 800. The container 600 of the first sensor assembly SA1 functions as a buffer to prevent ink that has leaked from any of the six fill tanks FT and passed through the supply-side air flow path AT1 from flowing into the first air regulator AR1. The container 600 of the second sensor assembly SA2 functions as a buffer to prevent ink that has leaked from any of the six drain tanks DT and passed through the recovery-side air flow path AT2 from flowing into the second air regulator AR2.

[0072] The sensor 800 of the first sensor assembly SA1 and the sensor 800 of the second sensor assembly may be, for example, a known float sensor. Each sensor 800 includes a shaft 800a, a float 800b inserted into the shaft 800a, and a signal output device (not shown). The float 800b moves up and down along the shaft 800a depending on the amount of ink in the container 600, in other words, the position of the ink level in the container 600. The signal output device outputs a signal to the controller 700 according to the position of the float 800b moving up and down along the shaft 800a, that is, the position of the ink level in the container 600. In the first sensor assembly SA1, when the position of the ink level stored in the container 600 is equal to or higher than a predetermined position in the internal space 670 of the container 600 (for example, the position indicated by the dashed line in FIG. 9B), the signal output device of the sensor 800 outputs an ON signal indicating the presence of ink in the container 600 to the controller 700. On the other hand, when the position of the liquid level of the ink stored in the container 600 has not reached the predetermined position, the signal output device of the sensor 800 outputs an OFF signal to the controller 700. That is, the controller 700 detects whether or not ink leaking from any of the six fill tanks FT is present in the container 600 of the first sensor assembly SA1 based on a signal from the signal output device of the first sensor assembly SA1. Similarly, in the second sensor assembly SA2, when the position of the liquid level of the ink stored in the container 600 is equal to or higher than a predetermined position in the internal space 670 of the container 600 (for example, the position indicated by the dashed line in FIG. 9B), the signal output device of the sensor 800 outputs an ON signal indicating the presence of ink in the container 600 to the controller 700. On the other hand, when the position of the liquid level of the ink stored in the container 600 has not reached the predetermined position, the signal output device of the sensor 800 outputs an OFF signal to the controller 700. That is, the controller 700 detects whether or not ink leaked from any of the six drain tanks DT is present in the container 600 of the second sensor assembly SA2 based on a signal from the signal output device of the second sensor assembly SA2.

[0073] The container 600 has a top wall 610, a side wall 620, a flange 630, an annular plate 640, a bottom plate 650, and a cap 660. The top wall 610, the side wall 620, the bottom plate 650, and the cap 660 define an interior space 670 of the container 600.

[0074] The upper wall 610, the side wall 620, and the flange 630 are integrally molded from, for example, polyoxymethylene (POM) resin. The upper wall 610 is, for example, circular, and the flange 630 is, for example, annular. The side wall 620 connects the circumference of the upper wall 610 and the inner peripheral edge of the flange 630.

[0075] The upper wall 610 is formed with seven cylindrical connection parts CP communicating with the internal space 670 and one through hole TH for inserting the sensor 800. The seven connection parts CP are arranged along the circumference of the upper wall 610. One through hole TH is located in the center of the upper wall 610. A shaft 800a of the sensor 800 is inserted into one through hole TH. An annular float 800b is located in the internal space 670 of the container 600, and a portion of the shaft 800a located in the internal space 670 is inserted into a central hole of the annular float 800b. When the sensor 800 is inserted into the through hole TH and viewed from above, the sensor 800 is located inside the seven connection parts CP with respect to the circumference of the upper wall 610.

[0076] In the first sensor assembly SA1, the six connectors CP are fluidly connected to the six supply air flow paths AT1, respectively, and one connector CP is fluidly connected to the first air regulator AR1 via a pipe T1. In the second sensor assembly SA2, the six connectors CP are fluidly connected to the six recovery air flow paths AT2, respectively, and one connector CP is fluidly connected to the second air regulator AR2 via a pipe T2. That is, the first air regulator AR1 is fluidly connected to one connector CP of the first sensor assembly SA1 via the pipe T1. The second air regulator AR2 is fluidly connected to one connector CP of the second sensor assembly SA2 via the pipe T2.

[0077] Seven ribs 610a are formed on the lower surface of the upper wall 610, each extending downward. The seven ribs 610a are lined up along the circumference of the upper wall 610. Each rib 610a is located between two adjacent connection parts CP. Each rib 610a prevents ink flowing into the internal space 670 from one of the two adjacent connection parts CP, from flowing down the lower surface of the upper wall 610 into the other connection part CP.

[0078] The annular plate 640 and the bottom plate 650 are each formed of, for example, stainless steel (SUS). The bottom plate 650 is fixed to the lower surface of the flange 630 with a plurality of bolts BT in a state in which the annular plate 640 is placed on the upper surface of the flange 630. In other words, the flange 630 is sandwiched between the annular plate 640 and the bottom plate 650 from above and below.

[0079] The bottom plate 650 is formed with an outlet 650a penetrating the bottom plate 650. The cap 660 is attached to the lower surface of the bottom plate 650 to close the outlet 650a. The ink accumulated in the internal space 670 of the container 600 is discharged from the outlet 650a by removing the cap 660 from the bottom plate 650.

[0080] <Effects of this embodiment> The sensor 800 of the first sensor assembly SA1, the sensor 800 of the second sensor assembly SA2, the first air regulator AR1, and the second air regulator AR2 are all electrically connected to the controller 700.

[0081] In each head system 100, when ink flows from the fill tank FT to the drain tank DT via the head mechanism 40, the controller 700 drives the first air regulator AR1 and the second air regulator AR2 so that the pressure in the fill tank FT becomes higher than the pressure in the drain tank DT. In this case, in order to prevent ink from leaking from the multiple nozzles 3 of the head mechanism 40, the controller 700 drives the first air regulator AR1 and the second air regulator AR2 so that the pressures in the fill tank FT and the drain tank DT are maintained at negative pressure.

[0082] Here, for example, while ink is being supplied from the ink tank 400 to the fill tank FT and the drain tank DT, a malfunction may occur in the liquid level sensor (not shown) of the fill tank FT and / or the liquid level sensor (not shown) of the drain tank DT. In such a case, the supply of ink to the fill tank FT and / or the drain tank DT may not stop, and ink may leak from the fill tank FT and / or the drain tank DT. The ink leaking from the fill tank FT and / or the drain tank DT may flow into the container 600 of the first sensor assembly SA1 and / or the container 600 of the second sensor assembly SA2 via the supply side air flow path AT1 and / or the recovery side air flow path AT2.

[0083] When the controller 700 detects the presence of ink in the container 600 based on a signal from the sensor 800 of the first sensor assembly SA1 and / or detects the presence of ink in the container 600 based on a signal from the sensor 800 of the second sensor assembly SA2, the controller 700 stops driving the first air regulator AR1, the second air regulator AR2, and the pump P of the HPM 500. This makes it possible to detect ink leakage from the fill tank FT and the drain tank DT of the head system 100, and to prevent the leaked ink from flowing into the first air regulator AR1 and the second air regulator AR2.

[0084] In each of the first sensor assembly SA1 and the second sensor assembly SA2, seven connection parts CP are formed on the upper wall 610 of the container 600. For this reason, for example, ink that flows in from one connection part CP and is stored in the internal space 670 of the container 600 is unlikely to flow into other connection parts CP.

[0085] In addition, when the controller 700 drives the first air regulator AR1 and the second air regulator AR2 so that the inside of the fill tank FT and the inside of the drain tank DT are maintained at negative pressure, the internal space 670 of the first sensor assembly SA1 and the internal space 670 of the second sensor assembly SA2 are also maintained at negative pressure. For this reason, if the container 600 of the first sensor assembly SA1 and the container 600 of the second sensor assembly SA2 do not include the annular plate 640, there is a risk that the resin flange 630 will deform so as to move away from the bottom plate 650. In this regard, in this embodiment, the resin flange 630 is sandwiched in the vertical direction by the annular plate 640 and the bottom plate 650 made of stainless steel, which have higher rigidity than resin, so that the above-mentioned deformation of the flange 630 can be suppressed.

[0086] [Variations] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various design modifications are possible within the scope of the claims.

[0087] In each of the first sensor assembly SA1 and the second sensor assembly SA2 in the above-described embodiment, the connection part CP of the container 600 is formed on the top wall 610, but this is not limiting. For example, the connection part CP may be formed on the side wall 620 of the container 600. In this case, the connection part CP may be located above the position of the ink liquid level in the container 600 when the sensor 800 detects the presence of ink in the container 600. Alternatively, the connection part CP may be located above the position of the ink liquid level in the container 600 when the controller 700 stops driving the first air regulator AR1, the second air regulator AR2, and the pump P of the HPM 500.

[0088] Although each of the first sensor assembly SA1 and the second sensor assembly SA2 in the above embodiment has a float sensor as the sensor 800, this is not limiting. The sensor 800 only needs to be able to detect at least whether or not ink is present in the container 600, and may be, for example, a known optical liquid level detection sensor equipped with a light-emitting unit and a light-receiving unit, or may be a known capacitance-type or electrode-type liquid level detection sensor.

[0089] The printer 1000 in the above embodiment has six head systems 100 that eject ink of six colors, but is not limited to this. For example, the printer 1000 may have four head systems 100 that eject ink of only four colors, black, cyan, magenta, and yellow. In this case, the first sensor assembly SA1 and the second sensor assembly SA2 are each fluidly connected to the four head systems via four air flow paths. Alternatively, the printer 1000 may have a plurality of head systems that eject ink of other colors in addition to the six head systems 100. In this case, the printer 1000 may further have a third sensor assembly fluidly connected to a plurality of fill tanks FT of the plurality of head systems, and a fourth sensor assembly fluidly connected to a plurality of drain tanks DT of the plurality of head systems.

[0090] In the above embodiment, after stopping the operation of the first air regulator AR1, the second air regulator AR2, and the pump P of the HPM500, the controller 700 may display a message on a display unit (not shown) of the printer 1000 encouraging the user to remove the cap 660 of the container 600 and drain the ink that has flowed into the container 600 from the outlet 650a.

[0091] The liquid ejected from the nozzles 11a is not limited to ink, and may be a liquid other than ink (for example, a treatment liquid that aggregates or precipitates components in the ink).

[0092] The print medium PM is not limited to paper, but may be, for example, cloth, a resin material, or the like.

[0093] The above embodiment and its modified examples are illustrative in all respects and should not be considered as limiting. For example, the number and configuration of the head mechanisms 40 may be changed. The number of colors that the printer 1000 can print simultaneously is not limited, and the printer 1000 may be configured to be equipped with multiple head systems 100 but capable of single-color printing only. The number, shape, position, etc. of the various flow paths may also be changed as appropriate. [Explanation of symbols]

[0094] 10. Chassis 20 Subtank 40 Head mechanism 100 Head System 400 Ink Tank 500 HPM 600 containers 700 Controller 800 Sensors 1000 Printers AR1 First Air Regulator AR2 Second Air Regulator AT1 Supply air flow path AT2 Recovery air flow path CP Connection DT Drain Tank FT Fill Tank SA1 First Sensor Assembly SA2 Second Sensor Assembly T1, T2 pipeline

Claims

1. a first inkjet head having a circulation flow path connecting a first supply port and a first recovery port, a first supply tank fluidly connected to the first supply port, and a first recovery tank fluidly connected to the first recovery port; a second inkjet head having a circulation flow path connecting a second supply port and a second recovery port, the second inkjet head including a second supply tank fluidly connected to the second supply port and a second recovery tank fluidly connected to the second recovery port; a first supply air flow passage fluidly connected to the first supply tank and a second supply air flow passage fluidly connected to the second supply tank; a first sensor assembly fluidly connected to the first supply air flow path and the second supply air flow path; a first air regulator fluidly connected to the first sensor assembly; a first recovery air flow passage fluidly connected to the first recovery tank, and a second recovery air flow passage fluidly connected to the second recovery tank; a second sensor assembly fluidly connected to the first return air flow path and the second return air flow path; a second air regulator fluidly connected to the second sensor assembly; the first sensor assembly includes a first sensor configured to detect the presence or absence of a first liquid within the first sensor assembly; The second sensor assembly includes a second sensor configured to detect the presence or absence of a second liquid within the second sensor assembly.

2. The first sensor assembly includes a first container defining a first space; the first sensor detects the presence of the first liquid in the first sensor assembly when a liquid level of the first liquid in the first space is equal to or higher than a first position in the first space; the first container has a first supply side connection part fluidly connected to the first supply side air flow path and a second supply side connection part fluidly connected to the second supply side air flow path, the first supply side connection portion and the second supply side connection portion are located above the first position in the first space, The second sensor assembly includes a second container defining a second space; the second sensor detects the presence of the second liquid in the second sensor assembly when a liquid level of the second liquid in the second space is equal to or higher than a second position in the second space; the second container has a first recovery side connection part fluidly connected to the first recovery side air flow passage and a second recovery side connection part fluidly connected to the second recovery side air flow passage, The pressure regulating device according to claim 1 , wherein the first recovery side connecting portion and the second recovery side connecting portion are located above the second position in the second space.

3. The first container has an upper wall that defines the first space, the first supply side connection portion and the second supply side connection portion are formed on the upper wall of the first container, The second container has an upper wall that defines the second space, The pressure regulating device according to claim 2 , wherein the first recovery side connecting portion and the second recovery side connecting portion are formed on the upper wall of the second container.

4. the top wall of the first container is circular; the first supply side connection portion and the second supply side connection portion are aligned along a circumference of the top wall of the first container, the first sensor is located on the inner side of the first supply side connection portion and the second supply side connection portion with respect to a circumference of the upper wall of the first container when viewed from above, the top wall of the second container is circular; the first recovery side connection portion and the second recovery side connection portion are aligned along a circumference of the upper wall of the second container, The pressure regulating device according to claim 3 , wherein the second sensor is located on the inner side of the first recovery side connecting portion and the second recovery side connecting portion with respect to a circumference of the upper wall of the second container when viewed from above.

5. the upper wall of the first container has a rib located between the first supply side connection portion and the second supply side connection portion and extending downward from a lower surface of the upper wall of the first container; The pressure regulating device according to claim 3 , wherein the upper wall of the second container has a rib located between the first recovery side connection portion and the second recovery side connection portion and extending downward from a lower surface of the upper wall of the second container.

6. the first container further includes a supply side connection portion fluidly connected to the first air regulator and located above the first position in the first space; The pressure regulating device according to claim 2 , wherein the second container further includes a recovery side connection portion that is fluidly connected to the second air regulator and is located above the second position in the second space.

7. The first container has an upper wall that defines the first space, the supply side connection is located on the top wall of the first container; The second container has an upper wall that defines the second space, The pressure regulating device according to claim 6 , wherein the recovery side connection portion is located on the top wall of the second container.

8. The first container further includes a flange, an annular plate, and a bottom plate that defines the first space. The flange of the first container is sandwiched between the bottom plate of the first container and the annular plate of the first container, The second container further includes a flange, an annular plate, and a bottom plate that defines the second space. The pressure regulating device according to claim 2 , wherein the flange of the second container is sandwiched between the bottom plate of the second container and the annular plate of the second container.

9. the first container further includes a bottom plate that defines the first space, an outlet for the first liquid that is formed in the bottom plate of the first container, and a first cap that closes the outlet of the first container; The pressure regulating device of claim 2, wherein the second container further has a bottom plate that forms the second space, an outlet for the second liquid formed in the bottom plate of the second container, and a second cap that closes the outlet of the second container.

10. a controller connected to the first air regulator, the second air regulator, the first sensor, and the second sensor; 2. The pressure regulating device of claim 1, wherein the controller is configured to stop the first air regulator and the second air regulator when the first sensor detects the presence of the first liquid in the first sensor assembly and / or when the second sensor detects the presence of the second liquid in the second sensor assembly.

11. The first sensor assembly has a first container defining a first space; the first sensor is located within the first space; the first container has a first supply side connection part fluidly connected to the first supply side air flow path and a second supply side connection part fluidly connected to the second supply side air flow path, the first supply side connection portion and the second supply side connection portion are located above a liquid level of the first liquid in the first space when the controller stops the first air regulator and the second air regulator, The second sensor assembly has a second container defining a second space; the second sensor is located within the second space; the second container has a first recovery side connection part fluidly connected to the first recovery side air flow passage and a second recovery side connection part fluidly connected to the second recovery side air flow passage, The pressure regulating device according to claim 10, wherein the first recovery side connection portion and the second recovery side connection portion are located above a liquid level of the second liquid in the second space when the controller stops the first air regulator and the second air regulator.

12. A pressure adjusting device according to any one of claims 1 to 10; a transport device that transports a medium relative to the first inkjet head and the second inkjet head.

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