HEAD SYSTEM, LIQUID EJECTION APPARATUS, IMAGE FORMING APPARATUS, AND LIQUID SUPPLY METHOD

Abstract

To provide a head system which can adjust a temperature of a liquid to be supplied to a liquid discharge head preferably.SOLUTION: A head system includes: multiple heads; a sub tank which is connected to each of the multiple heads and distributes a liquid into each of the multiple heads; a supply passage which supplies the liquid to the sub tank; a heater which heats the liquid in the supply passage; and a housing which houses the sub tank, the supply passage, and the heater.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a head system, a liquid ejection apparatus, an image forming apparatus, and a liquid supplying method. [Background technology]

[0002] There are image recording devices that eject liquid such as ink onto a medium such as paper via a liquid ejection head. In such image recording devices, a structure is used in which the liquid to be supplied to the liquid ejection head is heated by a heater (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-207064 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a head system, a liquid ejection apparatus, an image forming apparatus, and a liquid supplying method that are capable of suitably adjusting the temperature of liquid supplied to a liquid ejection head. [Means for solving the problem]

[0005] According to a first aspect of the present invention, Multiple heads and a sub-tank connected to each of the plurality of heads and distributing liquid to each of the plurality of heads; a supply flow path for supplying the liquid to the subtank; a heater for heating the liquid in the supply flow path; There is provided a head system including a housing that houses the sub-tank, the supply flow path, and the heater.

[0006] According to a second aspect of the present invention, A head system according to a first aspect; A liquid ejection apparatus including a control unit for controlling the head system, There is provided a liquid ejection device in which the control unit controls the head system so that an amount of increase in temperature of the liquid caused by the heater is greater than an amount of increase in temperature of the liquid caused by the sub-tank heater.

[0007] According to a third aspect of the present invention, A liquid ejection device according to a second aspect; and a transport device that transports a medium toward the plurality of heads.

[0008] According to a fourth aspect of the present invention, A liquid supplying method for supplying liquid to a plurality of heads in a head system, comprising the steps of: While supplying the liquid to a subtank through a supply flow path, a control unit that controls the head system controls a heater that heats the liquid in the supply flow path to increase the temperature of the liquid by ΔT1° C.; Next, a subtank heater that heats the liquid in the subtank is controlled by the control unit to increase the temperature of the liquid in the subtank by ΔT2° C., which is smaller than ΔT1° C.; Then, the liquid in the subtank is sent to each of the plurality of heads. Effect of the Invention

[0009] According to the present invention, it is possible to provide a head system, a liquid ejection apparatus, an image forming apparatus, and a liquid supplying method that are capable of suitably adjusting the temperature of liquid supplied to a liquid ejection head. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a printer according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic perspective view of a head system according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a plan view of the left wall of the first portion of the housing as viewed from the outside (left side). [Figure 4] Fig. 4(a) is a perspective view of a preheating flow path. Fig. 4(b) is a cross-sectional view taken along line BB in Fig. 4(a). Fig. 4(c) is a diagram showing the arrangement of ink flow paths in a flow path block. Fig. 4(d) is a side view of the flow path block as viewed from the rear. [Diagram 5] FIG. 5 is an exploded perspective view in which the top plate is separated from the subtank. [Figure 6] FIG. 6 is a bottom view of the subtank. [Figure 7] FIG. 7 is an explanatory diagram showing the connection relationship between each storage portion of the subtank and each circulation port of the ink circulation port set. [Figure 8] FIG. 8 is a partial bottom perspective view of the main body of the subtank, showing the structure of the distribution flow paths that connect each storage portion of the subtank with each flow port of the ink flow port set. [Figure 9] FIG. 9 is a perspective view of the head mechanism. [Figure 10] FIG. 10 is a perspective view of a flow path block of the head mechanism. [Figure 11] 11 is an exploded perspective view showing the configuration below the flow path block in the head mechanism, and the enclosed drawing is a perspective view of the heat transfer member as seen from below. [Figure 12] FIG. 12 is a plan view of the flow passage unit and the actuator. [Figure 13] FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. [Figure 14] Fig. 14 is a side view of the head mechanism, in which some of the configuration is seen through for the purpose of illustrating the arrangement. [Figure 15] FIG. 15 is a plan view showing the arrangement of the ten head mechanisms at the bottom of the housing. [Figure 16] FIG. 16 is a side view of each ink tube included in the ink tube set. [Figure 17] FIG. 17 is a schematic perspective view of the refrigerant distribution mechanism. [Figure 18] FIG. 18 is an explanatory diagram showing the arrangement of components in the housing in the front-rear direction. [Figure 19] 19 is a perspective view showing the arrangement of the preheating flow path, the ink tube set, and the coolant flow mechanism above the head mechanism. Only a portion in the left-right direction of the flow path block 21 of the preheating flow path 20, the coolant supply manifold 51 of the coolant flow mechanism, and the coolant discharge manifold 53 are shown. The preheating flow path 20 is drawn with dotted lines as a transparent structure so as not to obstruct the visual observation of the structure located behind it. [Figure 20] FIG. 20 is a schematic diagram of a flow path of the first ink in the head system. [Figure 21] FIG. 21 is a schematic diagram of a flow path of the second ink in the head system. [Figure 22] FIG. 22 is a side view of a flow path block included in a preheating flow path of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment] A head system 100, a liquid ejection device 900, and a printer (printing device) 1000 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 22. FIG.

[0012] <Printer 1000> As shown in FIG. 1, the printer 1000 mainly comprises four head systems 100, a platen 200, a pair of transport rollers 301, 302 as a transport device, an ink tank 400, a reservoir 500, a control unit 600, and a housing 700 that houses these components.

[0013] In the printer 1000, the direction in which the pair of transport rollers 301, 302 are aligned, i.e., the direction in which the medium PM is transported during image formation, is referred to as the "medium feed direction." Additionally, the direction that extends in the horizontal plane and is perpendicular to the medium feed direction is referred to as the "medium width direction."

[0014] Each of the four 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 frame 100a supports the four head systems 100 such that the front-rear direction (described later) of each of the four head systems 100 coincides with the medium feed direction (transport direction) of the printer 1000, and the nozzle surfaces 40n (described later) of the four head systems 100 face the upper surface of the platen 200. In Fig. 1, a frame 100a is provided for each head system 100, but the four head systems 100 may be collectively supported by a single frame 100a.

[0015] In this embodiment, each of the four head systems 100 is configured to eject two of four different types of ink. The four types of ink are, for example, cyan ink, magenta ink, yellow ink, and black ink. The specific structure and function of the head system 100 will be described later. The ink may be an ultraviolet-curable ink (UV ink).

[0016] The platen 200 is a plate-like member that supports the medium PM from the side opposite (below) the head system 100 when ink is ejected from the head system 100 toward the medium PM. Therefore, the upper surface of the platen 200 corresponds to the transport surface of the medium PM.

[0017] The pair of transport rollers 301, 302 are disposed on either side of the platen 200 in the medium feed direction. The pair of transport rollers 301, 302 function as a transport device that transports the medium PM in a predetermined manner in the medium feed direction when the head system 100 forms an image on the medium PM.

[0018] The ink tank 400 is divided into four sections so as to accommodate four different colors of ink. The four different colors of ink are sent to the reservoir 500 through a pipe 410. The reservoir 500 is also divided into four sections so as to accommodate four different colors of ink. The ink of each color sent to the reservoir 500 is circulated between the reservoir 500 and the head system 100 through pipes and pumps (not shown).

[0019] The control unit (controller) 600 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 control unit 600 includes an FPGA (Field Programmable Gate Array), an EEPROM (Electrically Eracable Programmable Read-Only Memory), and a RAM (Random Access Memory). The control unit 600 may also include a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). The control unit 600 is connected to an external device (not shown) such as a PC so as to be able to communicate data with the printer 1000, and controls each unit of the printer 1000 based on print data sent from the external device.

[0020] The liquid ejection device 900 of this embodiment includes a control unit 600 and at least one head system 100.

[0021] <Head System 100> 2, each of the four head systems 100 mainly includes a housing 10, two preheating paths 20 housed in the housing 10, a sub-tank 30, ten head mechanisms 40, ten ink tube sets ITS connecting the sub-tanks 30 and the ten head mechanisms 40, a coolant distribution mechanism 50, a relay board 70, and a control board unit 80. Since the four head systems have the same configuration, the following description focuses on one of the four.

[0022] 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 (first direction) of the head system 100, and the direction in which the ten head mechanisms 40 and the sub-tanks 30 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 (second direction) of the head system 100.

[0023] 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 30 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.

[0024] 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 medium feed direction of the printer 1000 .

[0025] <Case 10> The housing 10 may be made of, for example, metal. The housing 10 includes a first portion 11 and a second portion 12 that is detachable from the first portion 11.

[0026] The first portion 11 has a top plate 11a, a bottom portion 11b, a front wall 11c (FIG. 18; the illustration is omitted in FIG. 2 so that the inside of the first portion 11 can be seen), a rear wall 11d, a left wall (side wall) 11e, and a right wall 11f. The top plate 11a and the bottom portion 11b are rectangular in shape with a long width in a plan view. The top plate 11a has a step portion ST 11 The left wall 11c and the rear wall 11d are flat plates extending along a plane including the width direction and the up-down direction, and the left wall 11e and the right wall 11f are flat plates extending along a plane including the front-rear direction and the up-down direction. The left wall 11e and the right wall 11f are perpendicular to the front wall 11c (the rear surface of the inner wall 11c) and the rear wall 11d (the front surface of the rear wall 11d).

[0027] As shown in FIG. 3, an electric connector CN is provided on the upper part of the left wall 11e, and four air circulation ports AP 10 There are four air vents AP 10 Below are two ink supply ports ISP 10 and two ink outlets IDP 10 is provided, and below it is the coolant supply port CSP 10and refrigerant outlet CDP 10 In addition, the electrical connector CN, the air vent AP 10 The supply ports and discharge ports are not shown in FIG.

[0028] 2, the second portion 12 has a top plate 12a, a bottom plate 12b, a front wall 12c, a rear wall 12d, a left wall 12e, and a right wall 12f. When the second portion 12 is attached to the first portion 11, the bottom plate 12b of the second portion 12 abuts against the vicinity of the right end of the top plate 11a of the first portion 11.

[0029] <Preheating channel 20> The preheating flow path 20 is an ink supply port ISP of the housing 10. 10 The ink supplied to the head system 100 through the nozzle is sent to the subtank 30 while being heated.

[0030] 2, two preheating channels 20 are arranged side by side in the front-rear direction near the bottom 11b of the first portion 11 of the housing 10. Each of the two preheating channels 20 has an elongated shape, and is arranged so that its longitudinal direction coincides with the width direction of the head system 100. In addition, the preheating channels 20 are arranged in the ink flow direction in such a manner that the ink supply port ISP 10 2. The preheating flow path 20 is located downstream of the preheating flow path 20 and upstream of the sub-tank 30. Note that the preheating flow path 20 in Fig. 2 is drawn with a dotted line so as not to obstruct the visual observation of the structure located behind it.

[0031] As shown in Figures 4(a) to 4(d), each of the two preheating flow paths 20 has a flow path block 21, a heater module 22 thermally connected to the flow path block 21, and a radiation sheet 23 attached to the flow path block 21.

[0032] The flow path block 21 causes ink to flow along a flow path defined inside the flow path block 21, and applies heat to the ink from the heater module 22. The flow path block 21 is preferably made of a material with high thermal conductivity, and may be made of a metal such as aluminum, for example.

[0033] The flow path block 21 has a main body portion 211 and heater support pieces 212 and 213 formed integrally with the main body portion 211 .

[0034] The main body 211 has a rectangular bar shape and extends along the width direction of the head system 100. The main body 211 has a front surface 211c and a rear surface 211d that extend along a plane perpendicular to the front-rear direction of the head system 100.

[0035] As shown in FIG. 4B and FIG. 4C, the main body 211 includes an ink flow path IC 20 The ink flow path IC 20 includes a linear first portion A1 extending in the longitudinal direction (i.e., left-right direction) of the main body portion 211 within a plane including the left-right and front-rear directions, a linear second portion A2 located above the first portion A1 and extending parallel to the first portion A1, and a U-shaped folded portion A3 connecting the right end A1f of the first portion A1 and the right end A2f of the second portion A2.

[0036] The left end A1e of the first portion A1 is the ink flow path IC 20 The upstream end of ICa 20 The right end A1f of the first portion A1 is connected to the lower end A3b of the folded portion A3. The left end A2e of the second portion A2 is connected to the ink flow path IC 20 Downstream end ICb 20 The right end A2f of the second portion A2 is connected to the upper end A3a of the folded portion A3.

[0037] As shown in Figure 4(b), the ink flow path IC 20 The cross-sectional shape of the ink flow path IC is oval. The long axis of the oval is aligned in the vertical direction, and the short axis is aligned in the front-rear direction. 20 If the cross-sectional shape of the ink flow path IC is an ellipse, it will be 20This makes it easy to increase the contact area between the ink flowing through the main body 211 and the main body 211. Therefore, heat from the heater module 22 can be efficiently applied to the ink, and the amount of heat generated by the heater module 22 required to warm the ink can be reduced. This makes it possible to suppress an excessive temperature rise in the heater module 22, and ultimately to suppress an excessive temperature rise inside the housing 10.

[0038] Ink flow path IC 20 The length of the flow passage, i.e., the upstream end ICa 20 and downstream end ICb 20 The length of the ink flow path between the ink flow path IC and the ink flow path IC is, for example, about 600 mm to 900 mm. 20 The cross-sectional area (area of ​​the cross section perpendicular to the direction in which the flow path extends) is, for example, 5 mm 2 ~15mm 2 The flow path length and cross-sectional area are the flow path length and cross-sectional area of ​​the flow path defined in the flow path block 21, and are the flow path length and cross-sectional area of ​​the region where the heater module 22 heats the ink.

[0039] Ink flow path IC 20 The length of the ink flow passage IC is greater than the left-right dimensions of the first storage section R1 to the fourth storage section R4 (described later) of the subtank 30. 20 The cross-sectional area of ​​the first storage portion R1 to the fourth storage portion R4 of the subtank 30 is smaller than the cross-sectional area of ​​each of the first storage portion R1 to the fourth storage portion R4 of the subtank 30 taken along a plane perpendicular to the left-right direction.

[0040] Heater support piece 212 is an angle-shaped part that protrudes forward from the upper edge of front surface 211c of main body 211 and bends downward, and has a surface 212s facing front surface 211c (FIG. 4(b)). Heater support piece 213 is an angle-shaped part that protrudes forward from the lower edge of front surface 211c of main body 211 and bends upward, and has a surface 213s facing front surface 211c.

[0041] The front surface 211c and the heater support pieces 212 and 213 form a slit SL for accommodating the heater module 22. 21 is defined.

[0042] The heater module 22 generates heat to be applied to the flow path block 21. The heater module 22 includes a heater 221, a heat dissipation sheet 222, and a metal plate 223.

[0043] The heater 221 is a long planar (strip-shaped) heater. The heater 221 has a long heat generating surface 221m and an opposite surface 221n opposite to the heat generating surface 221m.

[0044] The heat dissipation sheet 222 dissipates excess heat generated by the heater 221 to the outside of the preheating flow path 20. The heat dissipation sheet 222 can be a long planar (strip-shaped) member made of an elastic material having high thermal conductivity, for example, silicone.

[0045] The heat dissipation sheet 222 is joined to the heater 221 with its longitudinal direction coinciding with the longitudinal direction of the heater 221. Specifically, one surface of the heat dissipation sheet 222 is joined to the opposite surface 221n of the heater 221.

[0046] The metal plate 223 dissipates excess heat transferred from the heater 221 to the heat dissipation sheet 222 to the outside of the preheating flow path 20. The metal plate 223 may be a long flat plate made of a material having high thermal conductivity, for example, aluminum.

[0047] The metal plate 223 is joined to the heat dissipation sheet 222 with its longitudinal direction aligned with the longitudinal direction of the heat dissipation sheet 222. Specifically, one surface of the metal plate 223 is joined to the entire surface of the heat dissipation sheet 222 opposite to the surface joined to the heater 221.

[0048] The heater module 22 has a slit SL 21 Inserted into the slit SL 21 In this state, the heat dissipation sheet 222 is compressed in the thickness direction, pressing the heater 221 and the metal plate 223 backward and forward, respectively. As a result, the heat generating surface 221m of the heater 221 is in close contact with the front surface 211c of the main body 211, and the metal plate 223 is in close contact with the surfaces 212s and 213s of the heater support pieces 212 and 213.

[0049] The radiation sheet 23 is provided to efficiently radiate heat to the outside from the flow path block 21. As shown in Fig. 4(d), the radiation sheet 23 is attached to the rear surface 211d in an area excluding the vicinity of the lower edge of the rear surface 211d of the main body 211 of the flow path block 21 and the vicinity of both longitudinal ends. The radiation sheet 23 may be a sheet formed of a material having a higher emissivity than the flow path block 21, such as a carbon sheet or heat-radiating silicone.

[0050] Near the lower left end of the rear surface 211d, that is, the ink flow path IC 20 The upstream end of ICa 20 A temperature measuring device TM is installed near the 20 Temperature Measuring Instrument TM 20 An example of a temperature measuring device is a thermistor. 20 is the ink flow path IC 20 Measures the temperature of the ink flowing into the 20 The ink temperature measured by the is sent to the control unit 600 via a relay substrate 70 (described later).

[0051] <Subtank 30> The sub-tank 30 receives and stores the ink that has been heated in the preheating flow path 20. The sub-tank 30 also heats the ink stored therein. The ink stored in the sub-tank 30 is distributed to each of the multiple head mechanisms 40.

[0052] 2, the sub-tank 30 is disposed above the two pre-heating paths 20. The sub-tank 30 has an elongated shape, and is disposed so that its longitudinal direction coincides with the width direction of the head system 100. The sub-tank 30 is located downstream of the pre-heating path 20 and upstream of the multiple head mechanisms 40 in the ink flow direction.

[0053] 5 and 6, the subtank 30 is composed of a main body 31, a top plate 32, and a bottom plate 33. A subtank heater 34 (FIG. 6) is attached to the lower surface of the bottom plate 33.

[0054] The main body 31 is formed of a resin such as POM, for example. The thermal conductivity of these resins is about 0.1 to 0.5 W / m·K.

[0055] The main body 31 has a front wall 31c and a rear wall 31d extending along a plane perpendicular to the front-rear direction of the head system 100, and a left wall 31e and a right wall 31f extending along a plane perpendicular to the width direction of the head system 100.

[0056] The left wall 31e and the right wall 31f have a stepped portion ST at the center in the front-rear direction. 31 The stepped portion ST 31 The front portions 31ec and 31fc are located in front of the stepped portion ST 31 It is located to the left of the rear portions 31ed and 31fd which are located behind the rear portions 31ed and 31fd.

[0057] The front portion 31ec has an ink supply port ISP at the front near the lower edge. 30 is provided, and behind it is the ink discharge port IDP 30 In addition, two air vents AP are provided near the upper edge. 30 The rear portion 31ed has an ink supply port ISP at the rear near the lower edge. 30 In front of it is the ink discharge port IDP. 30 In addition, two air vents AP are provided near the upper edge. 30 are arranged in a line at the front and back.

[0058] The main body 31 further has a first separation wall 31w1, a second separation wall 31w2, and a third separation wall 31w3 which are parallel to the front wall 31c and the rear wall 31d and extend between the left wall 31e and the right wall 31f.

[0059] The first separation wall 31w1 is formed by a step ST 31 The second separation wall 31w2 is provided at the same position as the ink supply port ISP of the front portion 31ec of the left wall 31e in the front-rear direction. 30 and ink outlet IDP 30 Between the two, there are two air vents AP30 The third separation wall 31w3 is provided between the ink supply port ISP of the rear portion 31ed of the left wall 31e in the front-rear direction. 30 and ink outlet IDP 30 Between the two, there are two air vents AP 30 It is set between.

[0060] The top plate 32 is, for example, a flat plate made of metal. The shape of the top plate 32 in a plan view is the same as the outline shape of the main body 31 when viewed from above. The top plate 32 is fixed to the upper end of the main body 31 with a seal rubber (not shown) sandwiched therebetween.

[0061] The bottom plate 33 is a flat plate made of metal (for example, aluminum, copper, stainless steel, etc.). The thermal conductivity of these metals is about 20 to 400 W / m·K, which is greater than the thermal conductivity of the resin that forms the main body 31. The shape of the bottom plate 33 in a plan view is the same as the outline of the main body 31 when viewed from above.

[0062] 6, ten ink circulation port sets S are provided on the lower surface of the bottom plate 33. Each of the ink circulation port sets S includes a first ink supply port SP1, a second ink supply port SP2, a first ink outlet port DP1, and a second ink outlet port DP2.

[0063] 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 first ink supply port SP1, the second ink supply port SP2, the first ink discharge port DP1, and the second ink discharge port DP2 are arranged in a staggered (zigzag) pattern along the width direction.

[0064] The bottom plate 33 is fixed to the lower end of the main body 31 with a sealing rubber (not shown) sandwiched therebetween.

[0065] As shown in FIG. 5, inside the subtank 30, a first storage section R1, a second storage section R2, a third storage section R3, and a fourth storage section R4 are defined by a main body section 31, a top plate 32, and a bottom plate 33, in that order from the front side.

[0066] The longitudinal dimension of each of the first to fourth storage sections R1 to R4, i.e., the dimension between the left wall 31e and the right wall 31f, is, for example, about 300 mm to 500 mm. Also, the cross-sectional area of ​​each of the first to fourth storage sections R1 to R4 (the area of ​​a cross section taken along a plane including the front-rear and up-down directions of the head system 100) is, for example, 1000 mm. 2 ~1500mm 2 That's about it.

[0067] Fig. 7 shows how the first storage portion R1, the second storage portion R2, the third storage portion R3, and the fourth storage portion R4 are connected to the ink flow port set S. Because Fig. 7 is a top view and Fig. 6 is a bottom view, the arrangement of the ten ink flow port sets S and the arrangement of each supply port and each discharge port in both figures are inverted up and down on the paper.

[0068] 7, the first storage portion R1 communicates with the first ink supply port SP1 (the supply port located at the front right of each set) of each ink circulation port set S. The second storage portion R2 communicates with the first ink exhaust port DP1 (the exhaust port located at the front left of each set) of each ink circulation port set S. The third storage portion R3 communicates with the second ink exhaust port DP2 (the exhaust port located at the rear right of each set) of each ink circulation port set S. The fourth storage portion R4 communicates with the second ink supply port SP2 (the supply port located at the rear left of each set) of each ink circulation port set S.

[0069] This configuration is realized, for example, by providing a distribution channel DC shown in Fig. 8 near the lower end of the main body 31. The distribution channel DC is defined by a three-dimensional structure formed integrally with each wall of the main body 31, and includes a tunnel-shaped channel DC1 connecting the first storage section R1 and the first ink supply port SP1, a tunnel-shaped channel DC2 connecting the second storage section R2 and the first ink discharge port DP1, a tunnel-shaped channel DC3 connecting the third storage section R3 and the second ink discharge port DP2, and a tunnel-shaped channel DC4 connecting the fourth storage section R4 and the second ink supply port SP2. Note that Fig. 8 only shows the vicinity of the left wall 31e of the main body 31.

[0070] The arrangement of the flow paths DC1 to DC4 is not limited to the arrangement shown in Fig. 8, and may be any arrangement as long as the flow paths from the bottoms of the first storage section R1 to the fourth storage section R4 to the corresponding supply ports or discharge ports do not interfere with each other. In addition, the distribution flow paths DC may be formed inside a flow path member separate from the main body section 31.

[0071] The sub-tank heater 34 applies heat to the ink stored in the first storage section R1 to the fourth storage section R4. The sub-tank heater 34 is a planar heater similar to the heater 221 of the preheating flow path 20, and is provided on the lower surface of the bottom plate 33 (FIG. 6).

[0072] In this embodiment, the subtank heater 34 is attached to the lower surface of the bottom plate 33 so as to be located between the ink circulation port sets S in the front-rear and width directions of the head system 100. Heat generated in the subtank heater 34 is provided to the distribution flow paths DC and the ink in the first storage portion R1 to the fourth storage portion R4 via the bottom plate 33, which is a metal plate.

[0073] The ink heated at the bottom of the first storage unit R1 to the fourth storage unit R4 moves to the upper part of the first storage unit R1 to the fourth storage unit R4 due to the rise in temperature. This causes ink convection inside each of the first storage unit R1 to the fourth storage unit R4, so that the ink inside the first storage unit R1 to the fourth storage unit R4 is efficiently heated.

[0074] Four air vents AP on the left wall 31e 30 The four air vents AP of the housing 10 10 The first to fourth storage sections R1 to R4 are connected to each other by pipes (not shown). The inside of each of the first to fourth storage sections R1 to R4 is divided into a liquid phase in which ink is stored and an air phase above the liquid phase in which air exists. 10 , AP 30 By making the gas phase pressure in the first storage section R1 and the fourth storage section R4 greater than the gas phase pressure in the second storage section R2 and the third storage section R3 via the head mechanism 40, an ink flow is generated from the first storage section R1 and the fourth storage section R4 through the head mechanism 40 to the second storage section R2 and the third storage section R3.

[0075] As shown in FIG. 6, among the five ink circulation port sets S arranged on the rear side of the head system 100 in the front-rear direction, temperature measuring devices TM are provided near the first, third, and fifth ink circulation port sets S from the left. 30 Each temperature measuring instrument is equipped with a temperature measuring instrument TM. 30 An example is a thermistor.

[0076] Temperature measuring device TM 30 Measures the temperature of the ink flowing out of the subtank 30. 30 The ink temperature measured by the is sent to the control unit 600 via a relay substrate 70 (described later).

[0077] <Head mechanism 40> The head mechanism 40 ejects toward the medium PM the ink supplied from the subtank 30. The head mechanism 40 also raises the temperature of the ink flowing inside.

[0078] 9, each of the ten head mechanisms 40 has, in order from the top, a connection plate 41, a pair of flow path blocks 42, an alignment frame 43, a cooling frame 44, a front-end frame 45, and a head 46. As shown in Fig. 11 and Fig. 14, a head heater mechanism 47 and a discharge control unit 48 are provided inside the front-end frame 45. 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 front-end frame 45, as shown in Fig. 14.

[0079] 9, the connection plate 41 is a plate-like member for connecting the head mechanism 40 and each of the pipelines connected to the head mechanism 40. The connection plate 41 is provided with six holes H penetrating the connection plate 41 in the thickness direction.

[0080] The first ink supply tube connection portion ISC1, the second ink supply tube connection portion ISC2, the first ink discharge tube connection portion IDC1, the second ink discharge tube connection portion IDC2, the refrigerant supply tube connection portion CSC, and the refrigerant discharge tube connection portion CDC are inserted into the six holes H of the connection plate 41, respectively.

[0081] Each of the connection parts ISC1, ISC2, IDC1, IDC2, CSC, and CDC is a cylindrical member. An O-ring (not shown) is provided at the lower end of each connection part so as to surround the lower end. Each connection part is inserted into hole H so that the O-ring is positioned within hole H, and protrudes to the upper surface side of connection plate 41. In this state, each connection part extends in the vertical direction perpendicular to connection plate 41.

[0082] The upper end of each connection part is configured to be connected to a one-touch joint (a joint configured so that the connection and fixation between the tubular member and the joint can be completed simply by inserting the tubular member into the joint). In other words, each connection part is a tubular member for a one-touch joint to which the one-touch joint is connected.

[0083] The pair of flow path blocks 42 define, below the connection plate 41, a flow path that supplies ink supplied from the sub-tank 30 to the head 46, and a flow path that discharges ink not ejected from the head 46 to the sub-tank 30.

[0084] Each of the pair of flow path blocks 42 is formed of a resin such as POM, for example, and has a rectangular plate-shaped main part MP, and a first base part BP1 and a second base part BP2 protruding from the main part MP, as shown in FIG.

[0085] The upper surface MPu of the main part MP has flow ports P1 and P2 formed side by side in the long side direction of the main part MP. The lower surface of the base part BP1 has flow ports P3 and P4 formed side by side in the thickness direction of the main part MP, and the lower surface of the base part BP2 has flow ports P5 and P6 formed side by side in the thickness direction of the main part MP.

[0086] A first groove G1 and a second groove G2 are formed on the surface MPi of the main portion MP.tp Extends obliquely downward from the first base portion BP1 to a lower end G1 bt1 A first portion G11 leading to the top portion G1 tp Extends obliquely downward from the lower end G1 toward the second base portion BP2 bt2 The second groove G2 includes a second portion G12 extending from the top G2 tp Extending obliquely downward from the first base portion BP1 to the lower end G2 bt1 A first portion G21 leading to the top portion G2 tp Extends obliquely downward from the second base portion BP2 to a lower end G2 bt2 and a second portion G22 leading to

[0087] Inside the main portion MP, there are provided a flow path C1 connecting the flow port P1 and the first groove G1, a flow path C2 connecting the flow port P2 and the second groove G2, a flow path C3 connecting the flow port P3 and the first groove G1, a flow path C4 connecting the flow port P4 and the second groove G2, a flow path C5 connecting the flow port P5 and the first groove G1, and a flow path C6 connecting the flow port P6 and the second groove G2.

[0088] The pair of flow path blocks 42 are joined with an elastic sheet (not shown) sandwiched therebetween so that the surfaces MPi face each other. The joined body of the pair of flow path blocks 42 is fixed to the lower surface of the connection plate 41 via a seal rubber (not shown). In this state, the flow ports P1 and P2 of the flow path block 42 located at the back side of the paper surface of Fig. 9 communicate with the second ink supply tube connection portion ISC2 and the second ink discharge tube connection portion IDC2 through the hole H of the connection plate 41, respectively, and the flow ports P1 and P2 of the flow path block 42 located at the front side of the paper surface of Fig. 9 communicate with the first ink supply tube connection portion ISC1 and the first ink discharge tube connection portion IDC1, respectively, through the hole H of the connection plate 41.

[0089] The alignment frame 43 is, for example, a flat plate member made of SUS. The alignment frame 43 has a central through hole TH, which is rectangular in plan view and penetrates the center from top to bottom. 43 and the central through hole TH 43 Eight ink flow paths ICs are arranged around the 43 and

[0090] The alignment frame 43 is fixed to the lower surfaces of the pair of flow path blocks 42. In this state, the circulation ports P3 to P6 on the lower surfaces of the pair of flow path blocks 42 are aligned with the ink flow paths IC of the alignment frame 43. 43 It is connected to.

[0091] The cooling frame 44 is a thick plate-like member having a rectangular shape in a plan view as shown in Fig. 11. The cooling frame 44 may be formed of a material having high thermal conductivity, such as aluminum, for example.

[0092] A refrigerant flow passage CC having a generally U-shaped planar shape is formed inside the cooling frame 44. The refrigerant flow passage CC is connected to a refrigerant supply port CSP on the top surface of the cooling frame 44. 44 and refrigerant outlet CDP 44 The refrigerant flow path CC is surrounded by eight ink flow paths IC 44 and the central through hole TH 44 and is provided.

[0093] The cooling frame 44 is fixed to the lower surface of the alignment frame 43. In this state, the eight ink flow paths IC 43 Each of the eight ink flow paths IC of the cooling frame 44 44 Each of the above is in communication with the other.

[0094] 9, a refrigerant supply pipe CST and a refrigerant discharge pipe CDT are provided between the connection plate 41 and the cooling frame 44. An O-ring (not shown) is provided at the upper end of the refrigerant supply pipe CST. The refrigerant supply pipe CST is connected to the connection plate 41 by inserting its upper end, together with the O-ring, from below into a hole H to which the refrigerant supply pipe connection part CSC of the connection plate 41 is connected. In addition, the lower end of the refrigerant supply pipe CST is inserted into a central through-hole TH of the alignment frame 43. 43 The cooling frame 44 has a coolant supply port CSP 44 is connected to.

[0095] An O-ring (not shown) is provided at the upper end of the refrigerant discharge pipe CDT. The refrigerant discharge pipe CDT is connected to the connection plate 41 by inserting the upper end thereof, together with the O-ring, from below into a hole H to which the refrigerant discharge pipe connection part CDC of the connection plate 41 is connected. In addition, the lower end of the refrigerant discharge pipe CDT is inserted into the central through hole TH of the alignment frame 43. 43 Coolant outlet CDP of cooling frame 44 via 44 is connected to.

[0096] The front end frame 45 is, for example, a flat plate member made of SUS. The front end frame 45 has a central through hole TH that is rectangular in plan view and penetrates the center from top to bottom. 45 and the central through hole TH 45 Eight ink flow paths ICs, each of which is roughly rectangular in plan view, are provided around the 45 and

[0097] The front end frame 45 is fixed to the lower surface of the cooling frame 44. In this state, the eight ink flow paths IC 45 Each of the eight ink flow paths IC of the cooling frame 44 44 Each of the above is in communication with the other.

[0098] The head 46 includes a flow passage unit 461 and a piezoelectric actuator 462 (FIGS. 11 and 12).

[0099] 13, the flow path unit 461 is a laminated structure in which an ink sealing film 461A, plates 461B to 461E, and a nozzle plate 461F are laminated in this order from above. As shown in FIG. 12, a flow path CH is formed inside the flow path unit 461.

[0100] The flow channel CH has eight ink flow ports IP 46 Each of the four manifold channels M1 to M4 is a linear channel, and has an ink flow port IP 46Each of the four manifold channels M1 to M4 is connected to 12 individual channels iCH.

[0101] As shown in FIG. 13, 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 461A. 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 461F. The lower surface of the nozzle plate 461F is the lower surface of the head mechanism 40, which is the nozzle surface 40n. A nozzle row L3 (FIG. 12) is formed in the nozzle surface 40n along the direction in which the manifold channels M1 to M4 extend.

[0102] 13, the piezoelectric actuator 462 is composed of a first piezoelectric layer L1 provided on the upper surface of the flow path unit 461, 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 provided on the upper surface of the second piezoelectric layer L2. The plurality of individual electrodes iET are provided on the upper surface of the second piezoelectric layer L2 so as to be located above the 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.

[0103] The head heater mechanism 47 applies heat to the head 46 to heat the ink flowing inside the head 46. As shown in FIG.

[0104] Heat transfer member 471 is made of a metal with high thermal conductivity, for example, aluminum. As shown in Fig. 11 (the enclosed diagram in Fig. 11 shows a perspective view of the bottom of heat transfer member 471) and Fig. 14, heat transfer member 471 has plate portion 471A having a substantially square shape in plan view, a pair of wall portions 471B protruding upward from both ends of the top surface of plate portion 471A, and frame-shaped protrusion portion 471C protruding downward from the outer edge of the bottom surface of plate portion 471A.

[0105] The heat transfer member 471 is attached to the upper surface of the head 46 so that the lower end of the frame-shaped protrusion 471C abuts against the flow passage unit 461 around (outside) the piezoelectric actuator 462. Note that a flexible printed circuit board 481 of the discharge control unit 48 is partially sandwiched between the frame-shaped protrusion 471C and the flow passage unit 461 (described later).

[0106] The film heater 472 has a generally square shape in a plan view. The film heater 472 is disposed on the heat transfer member 471 such that the heat generating surface of the film heater 472 is in contact with the upper surface of the plate portion 471A of the heat transfer member 471. The heat generated by the film heater 472 is provided to the flow passage unit 461 via the heat transfer member 471.

[0107] The leaf spring 473 is disposed on the upper surface of the film heater 472 .

[0108] 11 and 14, the discharge control unit 48 includes an FPC (Flexible Printed Circuits) 481 and a control board 482 on which a driver IC is mounted. The FPC 481 is not shown in FIG.

[0109] The FPC 481 is strip-shaped, and has a plurality of contacts (not shown) formed in a central portion 481A in the longitudinal direction.

[0110] The control board 482 is disposed above the leaf spring 473 of the head heater mechanism 47 and parallel to the plate portion 471A of the heat transfer member 471. The control board 482 is separated from the film heater 472 by the leaf spring 473 and is in contact with the cooling frame 44. In addition, the radiant heat of the film heater 472 is blocked by the leaf spring 473, and heating of the control board 482 is suppressed.

[0111] 14, the FPC481 is disposed on the upper surface of the piezoelectric actuator 462 such that each of the multiple contacts of the central portion 481A is electrically connected to each of the multiple individual electrodes iET of the piezoelectric actuator 462. An outer portion of the central portion 481A of the FPC481 passes between the heat transfer member 471 of the head heater mechanism 47 and the head 46, extends upward along the side surface of the heat transfer member 471, and is connected to the control board 482. As a result, each of the multiple individual electrodes iET of the piezoelectric actuator 462 is connected to the control board 482 via the FPC481.

[0112] The head 46 is fixed to the front end frame 45. In this state, eight ink flow ports IP 46 Each of the eight ink flow path ICs of the front end frame 45 45 The piezoelectric actuator 462, the head heater mechanism 47, and the discharge control unit 48 are connected to the central through hole TH of the front end frame 45. 45 It is placed inside.

[0113] As shown in FIG. 14, a temperature measuring device TM is provided on the upper surface of the flow passage unit 461 in the vicinity of the area in contact with the heat transfer member 471. 40 Temperature measuring instrument TM 40 An example of the temperature measuring device is a thermistor. 40 are omitted in FIG.

[0114] Temperature measuring device TM 40 The temperature measuring device TM measures the temperature of the ink flowing through the flow channel CH in the flow channel unit 461. 40 The ink temperature measured by the is sent to the control unit 600 via a relay substrate 70 (described later).

[0115] The wire connection portion WC is in the form of a board and extends vertically as shown in FIG. 14. The upper end of the wire connection portion WC is disposed above the connection plate 41 and adjacent to the connection plate 41. The lower end of the wire connection portion WC is inserted into the central through-hole TH of the front-end frame 45. 45The wiring connection portion WC is located inside the central through hole TH of the alignment frame 43. 43 , the central through hole TH of the cooling frame 44 44 It penetrates vertically.

[0116] A flexible substrate 71 extending from a relay substrate 70 is connected to the upper end of the wiring connection portion WC (described later). A film heater 472 of the head heater mechanism 47 and a temperature measuring device TM are connected to the lower end of the wiring connection portion WC. 40 A control board 482 of the discharge control unit 48 is connected to the discharge control unit 48.

[0117] Each of the head mechanisms 40 is fixed to the bottom 11b of the first portion 11 of the housing 10 via an alignment frame 43. In this state, the nozzle surface 40n of each head mechanism 40 is exposed toward the bottom of the housing 10. In addition, the nozzle row L3 of the nozzle surface 40n extends along the width direction of the head system 100.

[0118] 15, ten head mechanisms 40 are arranged in a staggered (zigzag) pattern along the width direction on the bottom 11b of the first portion 11 of the housing 10. Each of the ten head mechanisms 40 is provided such that the refrigerant supply pipe connection part CSC and the refrigerant discharge pipe connection part CDC are located on the front side, and the wiring connection part WC is located on the rear side.

[0119] Five head mechanisms 40 are arranged at equal intervals in the width direction of the head system 100 on the front side of the bottom 11b. The row of head mechanisms 40 on the front side of the bottom 11b is referred to as the front row FL as appropriate. The remaining five head mechanisms 40 are arranged at equal intervals in the width direction of the head system 100 on the rear side of the front row FL. The row of head mechanisms 40 on the rear side of the front row FL is referred to as the rear row RL as appropriate.

[0120] The coolant supply pipe connection portion CSC, the first ink discharge pipe connection portion IDC1, the coolant discharge pipe connection portion CDC, and the first ink supply pipe connection portion ISC1 are arranged in a staggered (zigzag) pattern in the width direction of the head system 100, in this order from left to right.

[0121] The second ink supply tube connection portion ISC2, the first ink discharge tube connection portion IDC1, the second ink discharge tube connection portion IDC2, and the first ink supply tube connection portion ISC1 are arranged in a staggered (zigzag) pattern in the width direction of the head system 100, in this order from left to right.

[0122] The second ink supply pipe connection portion ISC2, the coolant supply pipe connection portion CSC, the second ink discharge pipe connection portion IDC2, and the coolant discharge pipe connection portion CDC are arranged in a staggered (zigzag) pattern in the width direction of the head system 100, in this order from left to right.

[0123] Here, the arrangement of the ten head mechanisms 40 on the bottom 11b (FIG. 15) corresponds to the arrangement of the ten ink flow port sets S on the bottom plate 33 of the subtank 30 (FIGS. 6 and 7). That is, the ten head mechanisms 40 are each located directly below the ten ink flow port sets S.

[0124] Between one of the ten ink flow port sets S and the head mechanism 40 located directly below it, in a plan view, the first ink supply port SP1 and the first ink supply tube connection part ISC1 are at the same position, the second ink supply port SP2 and the second ink supply tube connection part ISC2 are at the same position, the first ink discharge port DP1 and the first ink discharge tube connection part IDC1 are at the same position, and the second ink discharge port DP2 and the second ink discharge connection part IDC2 are at the same position. That is, in a plan view, the center of each supply port or discharge port and the center of the flow path defined in each connection part coincide with each other.

[0125] <Ink flow path between the subtank 30 and the head mechanism 40> As shown in Fig. 2, each of the head mechanisms 40 is connected to the sub-tank 30 by an ink tube set ITS. Although the ink tube set ITS is shown by a single line in Fig. 2, it includes four pipes, namely, a first ink supply tube IST1, a second ink supply tube IST2, a first ink discharge tube IDT1, and a second ink discharge tube IDT2 (Fig. 19).

[0126] As shown in FIG. 16, the first ink supply tube IST1, the second ink supply tube IST2, the first ink discharge tube IDT1, and the second ink discharge tube IDT2 have the same shape as each other, and each have a main portion MT that extends linearly in the vertical direction, and a joint portion JT provided at the lower end of the main portion MT.

[0127] The main part MT is a circular pipe made of resin or metal. In this embodiment, the joint part JT is a one-touch joint. The outer diameter of the joint part JT is larger than the outer diameter of the main part MT. The joint part JT may be called a large diameter part, and the main part MT may be called a small diameter part.

[0128] Between each of the head mechanisms 40 and the ink flow port set S of the sub-tank 30 located directly above it, the upper end of the first ink supply tube IST1 is connected to the first ink supply port SP1, and the joint JT of the first ink supply tube IST1 is connected to the first ink supply tube connection part ISC1. The upper end of the second ink supply tube IST2 is connected to the first ink supply port SP2, and the joint JT of the second ink supply tube IST2 is connected to the second ink supply tube connection part ISC2. The upper end of the first ink discharge tube IDT1 is connected to the first ink discharge port DP1, and the joint JT of the first ink discharge tube IDT1 is connected to the first ink discharge tube connection part IDC1. The upper end of the second ink discharge tube IDT2 is connected to the second ink discharge port DP2, and the joint JT of the second ink discharge tube IDT2 is connected to the second ink discharge tube connection part IDC2.

[0129] As a result, the first ink supply tube IST1, the second ink supply tube IST2, the first ink discharge tube IDT1, and the second ink discharge tube IDT2 extend linearly in the vertical direction below the subtank 30 and above the multiple head mechanisms 40, throughout the entire area between the subtank 30 and the head mechanism 40, connecting the subtank 30 to each of the multiple head mechanisms 40.

[0130] 18 and 19, the flow path block 21 of the preheating flow path 20 is disposed near the ink tube set ITS. Therefore, the ink tube set ITS is heated by heat radiated from the radiation sheet 23 attached to the flow path block 21, and the ink flowing inside the ink tube set ITS is heated or the temperature of the ink flowing inside is maintained.

[0131] 18, for each head mechanism 40, the preheating flow path 20 directly above it is disposed in front of the first ink supply tube IST1 and the first ink discharge tube IDT1 so that the radiation sheet 23 attached to the flow path block 21 faces the outer circumferential surfaces of the first ink supply tube IST1 and the first ink discharge tube IDT1 connected to the head mechanism 40. Specifically, the preheating flow path 20 is disposed so that the lower end of the flow path block 21 is located above the upper end of the joint portion JT of the first ink supply tube IST1 and the first ink discharge tube IDT1, that is, so that the entire area of ​​the flow path block 21 in the vertical direction faces the main portion MT of the first ink supply tube IST1 and the first ink discharge tube IDT1. By making the position of the joint portion JT, which has an outer diameter larger than that of the main portion MT, different from the position of the flow path block 21 in the vertical direction, the gap between the radiation sheet 23 and the main portion MT of the first ink supply tube IST1 and the first ink discharge tube IDT1 can be reduced. Therefore, the preheating flow path 20 and the ink tube set ITS can be arranged compactly in the front-to-rear direction, and the heat radiated from the radiation sheet 23 of the preheating flow path 20 can be efficiently imparted to the ink flowing through the ink tube set ITS.

[0132] <Refrigerant distribution mechanism 50, cooling mechanism 60> The coolant flow mechanism 50 supplies a coolant (water, for example) to the ten head mechanisms 40 and discharges the coolant from the ten head mechanisms 40.

[0133] As shown in FIG. 2, the coolant flow mechanism 50 is disposed inside the first portion 11 of the housing 10, below the sub-tank 30 and above the multiple head mechanisms 40.

[0134] As shown in FIG. 17, the refrigerant flow mechanism 50 mainly includes two refrigerant supply manifolds 51 and ten refrigerant supply pipes 52 connected thereto, two refrigerant discharge manifolds 53 and ten refrigerant discharge pipes 54 connected thereto.

[0135] Each of the two coolant supply manifolds 51 is a straight circular pipe extending in the width direction of the head system 100, and has a coolant flow path defined therein. The coolant supply manifold 51 may be made of stainless steel, for example.

[0136] The upstream ends 51a of the two coolant supply manifolds 51 are connected to the coolant supply ports CSP of the first portion 11 of the housing 10 through pipes (not shown). 10 The downstream end 51b of the refrigerant supply manifold 51 is closed.

[0137] One of the two coolant supply manifolds 51 is located above five head mechanisms 40 included in the front row FL out of the ten head mechanisms 40. More specifically, as shown in Fig. 18, it is located behind the ink tube sets ITS connected to the head mechanisms 40 included in the front row FL and directly above the wiring connection parts WC of the head mechanisms 40 included in the front row FL.

[0138] The other of the two coolant supply manifolds 51 is located above the head mechanism 40 included in the rear row RL among the ten head mechanisms 40. More specifically, as shown in Fig. 18, it is located behind the ink tube set ITS connected to the head mechanism 40 included in the rear row RL and directly above the wiring connection parts WC of the five head mechanisms 40 included in the rear row RL.

[0139] The refrigerant supply pipes 52 are pipes that connect the refrigerant supply manifolds 51 and the refrigerant supply pipe connections CSC of the head mechanism 40. Five refrigerant supply pipes 52 are connected to each of the two refrigerant supply manifolds 51 at equal intervals.

[0140] 19, each of the refrigerant supply pipes 52 includes a straight portion 52A extending straight down from the refrigerant supply manifold 51, and a bent joint portion 52B connecting the straight portion 52A to the refrigerant supply pipe connection portion CSC. The bent joint portion 52B extends from the lower end of the straight portion 52A to the right front in a plane perpendicular to the up-down direction, to reach the refrigerant supply pipe connection portion CSC.

[0141] Each of the two coolant discharge manifolds 53 is a straight circular pipe extending in the width direction of the head system 100, and a coolant flow path is defined therein. The pipe diameter of the coolant discharge manifold 53 may be larger than the pipe diameter of the coolant supply manifold 51, and the diameter of the coolant flow path defined in the coolant discharge manifold 53 may be larger than the diameter of the coolant flow path defined in the coolant supply manifold 51. The coolant discharge manifold 53 may be made of stainless steel, for example.

[0142] The upstream ends 53a of the two coolant discharge manifolds 53 are closed. The downstream ends 53b of the two coolant discharge manifolds 53 are connected to the coolant discharge ports CDP of the first portion 11 of the housing 10 through pipes (not shown). 10 is connected to

[0143] 18, one of the two coolant discharge manifolds 53 is located directly above the coolant supply manifold 51 connected to the head mechanism 40 included in the front row FL and extends parallel to the coolant supply manifold 51. The other of the two coolant discharge manifolds 53 is located directly above the coolant supply manifold 51 connected to the head mechanism 40 included in the rear row RL and extends parallel to the coolant supply manifold 51.

[0144] The coolant discharge pipes 54 are pipes that connect the coolant discharge manifolds 53 and the coolant discharge pipe connection parts CDC of the head mechanism 40. Five coolant discharge pipes 54 are connected to each of the two coolant discharge manifolds 53 at equal intervals.

[0145] As shown in FIG. 19, each of the refrigerant discharge pipes 54 includes a straight portion 54A extending forward and downward from the refrigerant discharge manifold 53, and a bent joint portion 54B connecting the straight portion 54A to the refrigerant discharge pipe connection portion CDC.

[0146] The bent joint portion 54B extends leftward from the lower end of the straight portion 54A in a plane perpendicular to the up-down direction, and reaches the refrigerant discharge pipe connection portion CDC.

[0147] The refrigerant flow mechanism 50, the cooling frame 44 of the head mechanism 40, the refrigerant supply pipe CST, and the refrigerant discharge pipe CDT constitute a cooling mechanism 60 that cools the control board 482 of the discharge control unit 48. The cooling mechanism 60 cools the control board 482 by cooling the cooling frame 44, which the control board 482 abuts against, with the refrigerant.

[0148] <Relay board 70> The relay board 70 mainly serves as a relay between the control board unit 80 and the ejection control unit 48 of the head mechanism 40. The relay board 70 also distributes power supplied from the electrical connector CN of the housing 10 to the control board unit 80, the ejection control unit 48, and each heater in the housing 10.

[0149] 2 and 18, the relay board 70 is attached to the underside of the right end of the top board 11a in parallel to the top board 11a. That is, the mounting surface of the relay board 70 is parallel to the top and bottom surfaces of the top board 11a and is parallel to a plane including the width direction and the front-rear direction.

[0150] A rectangular opening OP that is long in the width direction of the head system 100 is provided in an area of ​​the top plate 11a located above the relay substrate .

[0151] 18, the relay board 70 is connected to each of the ten head mechanisms 40 by a flexible board 71. The flexible board 71 is provided with wiring connecting the control board unit 80 and the ejection control unit 48, and wiring connecting the control board unit 80 and the temperature measuring device TM 40 and wiring for supplying power to the head heater mechanism 47 and the discharge control unit 48.

[0152] One flexible substrate 71 is provided for each of the ten head mechanisms 40. One end of the flexible substrate 71 is connected to the wiring connection portion WC of the head mechanism 40, and the other end is connected to the relay substrate .

[0153] The relay board 70 is connected to the electrical connector CN on the left wall 11e of the first portion 11, the heater module 22 of the preheating flow path 20, and the heater 34 of the sub-tank 30 by wiring (not shown).

[0154] The relay board 70 is connected to the temperature measuring device TM of the preheating flow path 20 by wiring (not shown). 20 The relay board 70 is also connected to the temperature measuring device TM of the subtank 30 by wiring (not shown). 30 and is connected.

[0155] <Control board unit 80> The control board unit 80 receives print data signals from the control unit 600 of the printer 1000, and sends them to the ejection control units 48 of the head mechanisms 40 via the relay board 70. The control board unit 80 also receives the temperature measuring device TM 20 , T.M. 30 , T.M. 40 and transmits information therefrom to the control unit 600. The control board unit 80 is provided inside the second portion 12 of the housing 10 (FIG. 2).

[0156] A terminal (not shown) of the control board unit 80 protrudes downward through an opening (not shown) provided in the bottom plate 12b of the second part 12. The second part 12 is attached to and detached from the first part 11 by attaching and detaching the terminal to and from a connector (not shown) of the relay board 70 through an opening OP provided in the top plate 11a of the first part 11.

[0157] <Ink flow> 20 and 21, the flow of ink in the head system 100 will be summarized. The head system 100 can allow up to two types of ink to flow simultaneously.

[0158] As shown in FIG. 20, the reservoir 500 is connected to two ink supply ports ISP of the housing 10. 10 The ink supply port ISP on the front side 10 The first ink is supplied to the ink flow path IC 20 The upstream end of ICa 20 The ink flows into the ink passage IC 20 After the temperature is raised, the ink flow path IC 20 Downstream end ICb 20 The first ink is heated inside the preheating flow path 20 by the heater 221 of the heater module 22.

[0159] Ink flow path IC 20 Downstream end ICb 20 The first ink flows through a pipe to the ink supply port ISP of the subtank 30. 30 The first ink flows into the first storage portion R1 from the sub-tank heater 34. The first ink is heated in the first storage portion R1 by the sub-tank heater 34.

[0160] The first ink inside the first storage section R1 is supplied to each of the first ink supply ports SP1 of the ten ink circulation port sets S of the bottom section 33 by the distribution flow path DC at the bottom of the subtank 30, passes through the first ink supply tube IST1, and flows into the head mechanism 40 from the first ink supply tube connection parts ISC1 of each of the ten head mechanisms 40. At this time, the first ink flowing through the first ink supply tube IST1 is kept warm or heated by the heat radiated from the radiation sheet 23 of the preheating flow path 20.

[0161] The first ink that has flowed into the head mechanism 40 flows through the first and second manifolds M1 and M2 inside the head mechanism 40, and is ejected onto the medium PM from the nozzles 3 of the individual channels iCH connected to these. The temperature of the first ink flowing through the manifolds M1 and M2 is increased by the head heater mechanism 47.

[0162] The first ink that has not been ejected from the nozzle 3 flows from the first ink discharge pipe connection part IDC1 of the head mechanism 40 through the first ink discharge pipe IDT1 into the first ink discharge port DP1 of the ink circulation port set S, and reaches the second storage part R2 through the distribution flow path DC. 30 The ink flows out from the ink outlet IDP of the housing 10 through a pipe. 10 and is returned to the reservoir 500.

[0163] Here, the ink supply port ISP on the front side of the housing 10 10 downstream of the ink supply port ISP of the subtank 30 30 The upstream flow path of the front supply flow path IC S1 Front supply channel IC S1 indicates the ink supply port ISP on the front side of the housing 10 10 The ink flow path IC in the preheating flow path 20 on the front side from 20 Ink supply port ISP of subtank 30 30 It is a flow path leading to.

[0164] As shown in FIG. 21, the reservoir 500 is connected to two ink supply ports ISP of the housing 10. 10 The ink supply port ISP at the rear 10 The second ink (which may be of a different type from the first ink) supplied to the ink passage IC 10 of the rear pre-heating passage 20 passes through a pipe. 20 The upstream end of ICa 20 The ink flows into the ink passage IC 20 After the temperature is raised, the ink flow path IC 20 Downstream end ICb 20 The second ink is heated inside the preheating flow path 20 by the heater 221 of the heater module 22.

[0165] Ink flow path IC 20 Downstream end ICb 20 The second ink flows through a pipe to the ink supply port ISP of the subtank 30. 30 The second ink flows into the fourth storage portion R4 from the sub-tank heater 34. The second ink is heated inside the fourth storage portion R4 by the sub-tank heater 34.

[0166] The second ink inside the fourth storage section R4 is supplied to each of the second ink supply ports SP2 of the ten ink circulation port sets S of the bottom section 33 by the distribution flow path DC at the bottom of the subtank 30, passes through the second ink supply tube IST2, and flows into the head mechanism 40 from the second ink supply tube connection parts ISC2 of each of the ten head mechanisms 40. At this time, the second ink flowing through the second ink supply tube IST2 is kept warm or heated by the heat radiated from the radiation sheet 23 of the preheating flow path 20.

[0167] The second ink that has flowed into the head mechanism 40 flows through the third and fourth manifolds M3 and M4 inside the head mechanism 40, and is ejected onto the medium PM from the nozzles 3 of the individual channels iCH connected to these. The temperature of the second ink flowing through the manifolds M3 and M4 is increased by the head heater mechanism 47.

[0168] The second ink that is not ejected from the nozzle 3 flows from the second ink discharge pipe connection part IDC2 of the head mechanism 40 through the second ink discharge pipe IDT2 into the second ink discharge port DP2 of the ink circulation port set S, and reaches the third storage part R3 through the distribution flow path DC. 30 The ink flows out from the ink outlet IDP of the housing 10 through a pipe. 10 and is returned to the reservoir 500.

[0169] Here, the ink supply port ISP on the rear side of the housing 10 10 downstream of the ink supply port ISP of the subtank 30 30 The upstream flow path is the rear supply flow path IC S2 Rear supply channel IC S2 The ink supply port ISP on the rear side of the housing 10 10 The ink flow path IC in the preheating flow path 20 on the rear side from 20 Ink supply port ISP of subtank 30 30 It is a flow path leading to.

[0170] <Temperature control> Next, the temperature control of the ink flowing inside the head system 100, which is executed by the control unit 600 in the liquid ejection device 900 of this embodiment, will be described using an example in which the ink is UV ink.

[0171] The optimum ejection temperature of UV ink (the temperature most suitable for ejection from the nozzles 3 of the head mechanism 40) is approximately 39° C. to 41° C. Therefore, the control unit 600 controls the temperature of the ink flowing inside the head system 100 so that the temperature of the ink ejected from the nozzles 3 of the head mechanism 40 is approximately 40° C.

[0172] Here, we will explain the temperature control of ink flowing through the front flow path shown in Figure 20, but the temperature control of ink flowing through the rear flow path shown in Figure 21 is essentially the same as the temperature control of ink flowing through the front flow path.

[0173] The control unit 600 controls the temperature of the ink by controlling the output of the heater module 22 of the preheating flow path 20, the sub-tank heater 34 of the sub-tank 30, and the head heater mechanism 47 of the head mechanism 40. Note that, in this embodiment, the control unit 600 controls the temperature of the ink without actively controlling (changing) the flow rate (flow speed) of the ink flowing in the head system 100. However, the control unit 600 may be made to actively control the flow rate of the ink.

[0174] (1) Control of heater module 22 The control unit 600 controls the ink supply port ISP 10 The ink at T0 [°C] flowing into the head system 100 through the front supply flow channel IC S1 In other words, the control unit 600 controls the heater module 22 so that the temperature in the front supply flow path IC S1 The output of the heater module 22 is controlled with the target temperature of the ink temperature control in the ink tank 20 set to T1 [° C.].

[0175] Hereinafter, temperature T0 [°C] will be referred to as "initial temperature T0" and temperature T1 [°C] will be referred to as "supply flow path target temperature T1". In addition, the difference obtained by subtracting the initial temperature T0 from the supply flow path target temperature T1 is set to ΔT1, and hereinafter will be referred to as "supply flow path target temperature rise width ΔT1".

[0176] The control unit 600 is an ink flow path IC 20 The upstream end of ICa 20 A temperature measuring device TM installed near 20 Based on the output of the front supply channel IC S1 The ink flow path IC acquires the temperature of the ink flowing through the ink flow path. 20 The upstream end of ICa 20 Since no ink is heated upstream of the 20 The temperature of the ink obtained based on the output of is approximately equal to the initial temperature T0.

[0177] The control unit 600 is a temperature measuring device TM 20 The output of the heater module 22 is controlled based on the initial temperature T0 acquired via the front supply channel IC. The amount of heat given to the ink according to the output of the heater module 22 is S1 The temperature T1 is known based on the structure of the ink (the flow path length, the flow path cross-sectional area, the thermal conductivity of each structure, etc.) and the flow rate of the ink. Therefore, the control unit 600 can know the amount of output of the heater module 22 required to achieve the supply flow path target temperature T1 based on the initial temperature T0.

[0178] The initial temperature T0 is normal temperature (room temperature), and is usually about 20° C. to 25° C. The supply flow path target temperature T1 is about 34° C. to 36° C. in this embodiment. The supply flow path target temperature rise width ΔT1 is about 9° C. to 16° C. in this embodiment.

[0179] (2) Control of the subtank heater 34 The control unit 600 controls the ink supply port ISP 30The control unit 600 controls the subtank heater 34 so as to heat the ink that has flowed into the first storage section R1 of the subtank 30 via the ink supply passage 601 to T2 [°C] in the subtank 30. That is, the control unit 600 controls the output of the subtank heater 34 with the target temperature for ink temperature control in the subtank 30 set to T2 [°C].

[0180] Hereinafter, the temperature T2 [°C] will be referred to as the "subtank target temperature T2" ​​as appropriate. The difference obtained by subtracting the supply flow path target temperature T1 from the subtank target temperature T2 is set to ΔT2, and hereinafter will be referred to as the "subtank target temperature rise width ΔT2" as appropriate.

[0181] The control unit 600 detects the temperature of the subtank 30 by a temperature measuring device TM 30 The temperature of the ink flowing out from the sub-tank 30 to the first ink supply pipe IST1 is obtained based on the output of the temperature sensor 11. Then, the output of the sub-tank heater 34 is controlled so that the temperature coincides with the sub-tank target temperature T2.

[0182] In this embodiment, the subtank target temperature T2 is about 36° C. to 37° C. The subtank target temperature rise width ΔT2 is about 1° C. to 3° C. in this embodiment.

[0183] (3) Control of head heater mechanism 47 The control unit 600 controls the head heater mechanism 47 so as to heat the ink, which has flowed into the head mechanism 40 via the first ink supply pipe IST1, to T3 [°C] within the head mechanism 40. That is, the control unit 600 controls the output of the head heater mechanism 47 by setting the target temperature for ink temperature control within the head mechanism 40 to T3 [°C].

[0184] Hereinafter, the temperature T3 [° C.] will be referred to as the "target discharge temperature T3" as appropriate. The difference obtained by subtracting the sub-tank target temperature T2 from the target discharge temperature T3 is set to ΔT3, and hereinafter will be referred to as the "head target temperature rise width ΔT3" as appropriate.

[0185] The control unit 600 detects the temperature of the temperature measuring device TM provided on the upper surface of the flow path unit 451. 40Based on the output of , the temperature of the ink flowing in the manifolds M1 and M2 is obtained. Then, the output of the head heater mechanism 47 is controlled so that the temperature matches the target ejection temperature T3.

[0186] In this embodiment, the target ejection temperature T3 is approximately 39°C to 41°C, which is the optimum ejection temperature of the UV ink. The target head temperature rise width ΔT3 is approximately 2°C to 5°C in this embodiment.

[0187] As described above, the ink flowing through the ink supply pipe IST1 may be heated by radiant heat from the radiation sheet 23 of the preheating channel 20, and the temperature of the ink may rise due to the radiant heat. In this case, part of the target head temperature rise width ΔT3 is achieved by the radiant heat from the preheating channel 20.

[0188] In this way, the control unit 600 gradually warms the ink supplied to the head system 100 through the preheating channel 20, the sub-tank 30, and the head mechanism 40 so that the temperature of the ink becomes the optimum ejection temperature in the head mechanism 40. The sub-tank target temperature T2 is higher than the supply channel target temperature T1, and the target ejection temperature T3 is higher than the sub-tank target temperature T2. That is, the relationship T1 < T2 < T3 holds.

[0189] Also, the supply channel target temperature rise width ΔT1 is larger than the sub-tank target temperature rise width ΔT2 and the target head temperature rise width ΔT3.

[0190] Here, the significance of providing the preheating channel 20 in the head system 100 of this embodiment, and the significance of heating the ink in each of the preheating channel 20, the sub-tank 30, and the head mechanism 40 will be described.

[0191] Since it is desirable for a head system (head bar system) to be compact, it is considered to heat the ink in a sub-tank that is normally provided in the head system. However, the inventor of the present invention has found that heating in the sub-tank can cause deterioration in the quality of the formed image, and after extensive research, has found that the reason for this is the variation in ink temperature between multiple heads caused by heating the ink in the sub-tank. A specific explanation based on the inventor's findings is as follows.

[0192] The subtank is a tank for distributing ink to multiple heads, and is configured to allow ink flowing in from one inlet to flow out from multiple outlets. Here, the multiple outlets are provided one for each of the multiple heads, and their positions are different from one another. Therefore, the flow paths defined within the subtank, from the ink inlet to each of the multiple outlets, have different flow path lengths from one another. For example, in this embodiment, the ink supply port ISP provided on the left wall 31e of the subtank 30 is 30 The flow path lengths from the ink supply port SP1 to each of the multiple first ink supply ports SP1 arranged along the left-right direction are different from each other. The first ink supply port SP1 located on the leftmost side is the ink supply port ISP 30 Because it is close to the ink supply port ISP 30 The length of the flow path from the first ink supply port SP1 located on the leftmost side to the first ink supply port SP1 is the shortest. In contrast, the first ink supply port SP1 located on the rightmost side has the shortest length of the flow path among the multiple first ink supply ports SP1. 30 Because it is located far from the ink supply port ISP 30 The length of the flow passage from the first ink supply port SP1 located at the rightmost position is the longest.

[0193] Therefore, when heating ink with a heater in the sub-tank, the ink flowing out of the outlet located near the inlet to the sub-tank has a short flow path length in the heated area and a small temperature rise, whereas the ink flowing out of the outlet located far from the inlet to the sub-tank has a long flow path length in the heated area and a large temperature rise.

[0194] Specifically, for example, the ink supply port ISP of the subtank 30 in this embodiment 30 It was observed that when UV ink at 20° C. was supplied to first reservoir R1 from the ink supply port SP1 located at the leftmost position in the left-right direction, the ink flowing out from the ink supply port SP1 located at the rightmost position was about 26° C., and the ink flowing out from the ink supply port SP1 located at the rightmost position was about 36° C. In this case, a difference of about 10° C. occurs in the temperature of the ink flowing inside between the head mechanism 40 located at the leftmost position in the width direction of the head system 100 and the head mechanism 40 located at the rightmost position.

[0195] In this way, when the ink is heated from normal or room temperature (i.e., the initial temperature T0) by the subtank, since the multiple first ink supply ports SP1 are aligned along the direction in which the subtank heater extends, it is difficult to uniform the temperature of the ink flowing out of the multiple outlets, and therefore difficult to uniform the temperature of the ink flowing through each of the multiple heads. Therefore, the temperature and viscosity of the ink differs for each head, which can cause deterioration in the quality of the image formed on the medium by ejecting the ink.

[0196] In contrast, in this embodiment, a preheating flow path 20 is provided upstream of the subtank 30, and the ink flowing into the subtank 30 is heated in advance by the preheating flow path 20, thereby reducing the amount of temperature rise that must be achieved by heating in the subtank 30. Therefore, the range of variation in ink temperature between heads that may occur due to heating in the subtank 30 can be reduced.

[0197] Specifically, for example, when temperature control was performed using the head system 100 of this embodiment with the supply flow path target temperature T1 set to 34.7°C, the sub-tank target temperature T2 set to 36.5°C, and the target ejection temperature T3 set to 40°C, it was observed that the temperature variation of the UV ink flowing through each of the ten head mechanisms 40 was 0.6°C or less.

[0198] Furthermore, by providing the preheating flow path 20 in the head system 100 and directly connecting it to the upstream side of the subtank 30, the ink heated by the preheating flow path 20 can flow into the subtank 30 with almost no drop in temperature. Therefore, the ink can be efficiently heated to the optimum ejection temperature.

[0199] In addition, the fact that the preheating flow path 20 is directly connected to the upstream side of the sub-tank 30 means that no tank, pump, or valve is provided between the preheating flow path 20 and the sub-tank 30. In addition, in this embodiment, the downstream end ICb 20 and the ink supply port ISP of the subtank 30 30 The length of the ink flow path between the ink flow path IC 20 The flow path length is smaller than that of the

[0200] Furthermore, by providing the preheating flow path 20 in the head system 100, the heating capacity in the head system 100 is improved. Therefore, the ink can be heated to the optimum ejection temperature without reducing the flow rate of the ink flowing in the head system 100.

[0201] Since the head system 100 does not have a mechanism for cooling the ink in the ink flow path (the cooling mechanism 60 does not cool the ink), it is not possible to actively lower the temperature of the ink within the head system 100. Therefore, if the subtank target temperature T2 is made higher than the target ejection temperature T3 or if the supply flow path target temperature T1 is made higher than the target ejection temperature T3, the ink in the head mechanism 40 will exceed the target ejection temperature T3 (i.e., the optimal ejection temperature), and there is a risk of the quality of the formed image deteriorating. By making the supply flow path target temperature T1 and the subtank target temperature T2 lower than the target ejection temperature T3, such deterioration in image quality can be suppressed.

[0202] The effects of the head system 100 of this embodiment are summarized below.

[0203] The head system 100 of this embodiment has a preheating flow path 20 disposed inside the housing 10 and upstream of the sub-tank 30. Therefore, the temperature of the ink supplied to the head mechanism 40 can be suitably adjusted.

[0204] Specifically, for example, it is possible to suppress the variation in temperature of ink flowing through the multiple head mechanisms 40 by heating the ink through the preheating flow path 20. Also, even if the flow rate of ink flowing through the head system 100 is large, the ink can be sufficiently heated.

[0205] In addition, since the preheating flow path 20 is directly connected to the upstream side of the sub-tank 30, the ink heated by the preheating flow path 20 can flow into the sub-tank 30 with almost no temperature drop.

[0206] The effects of the liquid ejection device 900 of this embodiment, which is equipped with the head system 100 and the control unit 600, are summarized below.

[0207] In the liquid ejection device 900 of this embodiment, the control unit 600 controls the head system 100 so that the supply flow path target temperature rise width ΔT1 is larger than the sub-tank target temperature rise width ΔT2. This makes it possible to reduce the temperature rise width in the sub-tank 30, and suppress variations in ink temperature between the head mechanisms 40.

[0208] In the liquid ejection device 900 of this embodiment, the control unit 600 sets the subtank target temperature T2 higher than the supply flow path target temperature T1, and sets the target ejection temperature T3 higher than the subtank target temperature T2. In this way, by gradually increasing the target temperature of the temperature control from the upstream side to the downstream side, it becomes unnecessary to cool the ink in the flow path, and heating can be performed efficiently.

[0209] In the liquid ejection device 900 of this embodiment, the control unit 600 controls the head system 100 so that the supply flow path target temperature rise width ΔT1 is greater than the head target temperature rise width ΔT3. S1 ,I C S2 The majority of the heating is performed by the heater, and then the ink temperature is raised slightly by the subtank 30 and the head mechanism 40, and the ink temperature is adjusted slightly to approach the optimum ejection temperature. This type of stepwise temperature adjustment makes it possible to control the ink temperature more precisely.

[0210] [Variations] In the head system 100 of the above embodiment, the following modifications may also be used.

[0211] In the head system 100 of the above embodiment, the housing 10 includes, but is not limited to, the first part 11 and the second part detachable from the first part 11. The housing 10 may have any configuration, and the first part 11 and the second part 12 may be integrally formed inseparably.

[0212] In the head system 100 of the above embodiment, the pre-heating flow path 20 may have various configurations.

[0213] The ink flow path IC defined in the flow path block 21 of the preheating flow path 20 of the above embodiment 20 In the ink flow path IC, the first portion A1 and the second portion A2 extend within a plane including the left-right direction and the front-rear direction, that is, within a horizontal plane, but is not limited to this. 20 The upstream end ICa 20 From downstream end ICb 20 Specifically, for example, the first portion A1 may be provided so as to gradually rise from the left end A1e to the right end A1f, and the second portion A2 may be provided so as to gradually rise from the right end A2f to the left end A2e.

[0214] Ink flow path IC 20 The upstream end ICa 20 From downstream end ICb 20 By gradually increasing the ink flow path 20 This allows air bubbles mixed in the ink flow path IC to flow smoothly to the subtank 30. 20 This can suppress the occurrence of hot spots (localized high temperature areas caused by the heating of bubbles) inside the mold.

[0215] In addition, the ink flow paths IC defined in the flow path block 21 20 The ink flow path IC does not necessarily have to travel once in the longitudinal direction of the flow path block 21. 20 Specifically, the ink flow path IC may be a flow path that passes linearly between one end and the other end in the longitudinal direction of the flow path block 21, or may be a flow path that makes two or more round trips in the longitudinal direction of the flow path block 21. 20 By making the length longer, the heat of the flow path block 21 can be applied to the ink more efficiently.

[0216] Ink flow path IC 20 The cross-sectional shape of the ink flow path IC does not necessarily have to be elliptical. 20 The cross-sectional shape of the ink flow path IC can be made into any longitudinal shape such as an ellipse or a rectangle. 20This makes it easier to increase the contact area between the ink flowing through the flow path block 21 and the flow path block 21, and allows heat to be applied to the ink efficiently. In the present invention, the term "longitudinal shape" regarding the cross-sectional shape of the flow path means a two-dimensional shape in which the dimension in a certain direction is greater than the dimension in a direction perpendicular to the direction.

[0217] In the preheating flow path 20 of the above embodiment, the heater 221 of the heater module 22 abuts on substantially the entire area in the longitudinal direction of the flow path block 21, but this is not limited thereto. Specifically, for example, as shown in Fig. 22, a pair of heaters 221' may be provided in an area excluding the central part in the longitudinal direction of the flow path block 21.

[0218] Since heat given from the heater 221 to the flow path block 21 tends to gather in the central portion in the longitudinal direction of the flow path block 21, the central portion in the longitudinal direction of the flow path block 21 may be excessively heated by heat generated by the heater 221. By using a configuration in which a heater is not provided in the central portion in the longitudinal direction of the flow path block 21, such an excessive temperature rise in the central portion can be suppressed.

[0219] The area of ​​the region in the longitudinal center of the flow path block 21 where no heater is provided may be approximately 1 / 14 to 1 / 16 of the area of ​​the regions on both sides where the heaters are provided.

[0220] In the present invention, the "region where the heater is provided" refers to a region where the heating surface (heating element) of the heater is in contact directly or via a thin layer that can be thermally ignored. Therefore, for example, when a heater having a laminate structure in which a planar heating element made of an electric heating wire is sandwiched between a pair of protective layers is used, the region where the heating element is in contact via the protective layer corresponds to the "region where the heater is provided." On the other hand, a region where there is no heating element and only the protective layer is in contact is a region where part of the heater is provided, but does not correspond to the "region where the heater is provided" in the present invention.

[0221] The preheating flow path 20 does not need to have the flow path block 21. Specifically, for example, a planar heater may be attached directly to a tubular flow path. In this case, the area of ​​the tubular flow path to which the planar heater is attached corresponds to the "portion heated by the heater." Furthermore, each heater used in the above embodiment may be a linear heater.

[0222] In the liquid ejection device 900 of the above embodiment, the supply flow path target temperature T1, the subtank target temperature T2, the target ejection temperature T3, the supply flow path target temperature rise width ΔT1, the subtank target temperature rise width ΔT2, and the head target temperature rise width ΔT3 can be set appropriately.

[0223] It is desirable to make the supply flow path target temperature rise width ΔT1 as large as possible from the viewpoint of preventing variation in ink temperature among the multiple head mechanisms 40. ΔT1 may be, for example, ΔT / 2 or more, or ΔT / 1.5 or more, where ΔT is the difference obtained by subtracting the initial temperature T0 from the target discharge temperature T3 (hereinafter, appropriately referred to as "head system target temperature rise width ΔT").

[0224] Alternatively, each of the subtank target temperature rise width ΔT2 and the head target temperature rise width ΔT3 may be set to ⅓ or less of the supply flow path target temperature rise width ΔT1, or ¼ or less of the supply flow path target temperature rise width ΔT1.

[0225] In the liquid ejection device 900 of the above embodiment, the control unit 600 may perform control to increase the temperature of the ink in a short period of time when the temperature of the ink is low.

[0226] Specifically, for example, the control unit 600 controls the temperature measuring device TM of the subtank 30. 30 If the temperature of the ink flowing out of the subtank 30, which is obtained based on the output of the temperature measuring device TM of the subtank 30, is lower than the subtank target temperature T2, the temperature of the heater 221 of the heater module 22 of the preheating flow path 20 is set to a temperature higher than the subtank target temperature T2. This allows the ink in the preheating flow path 20 to be heated in a short time. After that, the control unit 600 controls the temperature measuring device TM of the subtank 30 to 30After the temperature of the ink flowing out of the subtank 30, which is obtained based on the output of the temperature sensor 600, reaches the subtank target temperature T2, the temperature of the heater 221 may be lowered to a temperature equal to or lower than the subtank target temperature T2. The control unit 600 may estimate the temperature of the heater 221 based on a predetermined calculation formula. Alternatively, the heater 221 may be provided with a thermistor to actually measure the temperature of the heater 221.

[0227] In the head system 100 of the above embodiment, the subtank 30 may not include the heater 34, and the head mechanism 40 may not include the head heater mechanism 47. In this case, the ink may be heated in the preheating flow path 20 from the initial temperature T0 to the target ejection temperature T3.

[0228] The head system 100 in the above embodiment includes ten head mechanisms 40 arranged in a staggered pattern along the width direction, but is not limited to this. The number of head mechanisms 40 included in the head system 100 is arbitrary. In an embodiment having at least three head systems 100, the head systems 100 may be arranged in a staggered pattern.

[0229] In the head system 100 of the above embodiment, each of the first and second ink supply tubes IST1, IST2 and the first and second ink discharge tubes IDT1, IDT2 has a main portion MT and a joint portion JT having an outer diameter larger than that of the main portion MT, but is not limited to this.

[0230] Specifically, for example, each of the first and second ink supply tubes IST1, IST2 and the first and second ink discharge tubes IDT1, IDT2 may have only a main portion MT. In this case, each ink tube can be connected to the head mechanism 40 by inserting a connection part such as the first ink supply tube connection part ISC1 into the lower end of the main portion MT. In this case, the large diameter portion corresponds to a portion of the ink tube whose outer diameter is increased by inserting a connection part (connection tube) into the ink tube, or a portion whose outer diameter is increased by surrounding the portion of the ink tube into which the connection part (connection tube) is inserted with a tightening member or the like.

[0231] Furthermore, the above-described connection between each ink tube and the head mechanism 40 may be applied to the connection between each ink tube and the sub-tank 30. In this case, each ink tube also has a large diameter portion at the upper end connected to the sub-tank 30.

[0232] The head system 100 in the above embodiment is configured to allow two types of ink to flow simultaneously, but is not limited to this. The head system 100 may be configured to allow only one type of ink to flow.

[0233] Specifically, for example, the subtank 30 is configured to have only two storage parts, the second ink supply port SP2 and the second ink discharge port DP2 are omitted from the ink circulation port set S, and the distribution flow path DC is configured such that one of the two storage parts communicates with the first ink supply port SP1 and the other of the two storage parts communicates with the first ink discharge port DP1. Furthermore, the second ink supply tube IST2 and the second ink discharge tube IDT2 are omitted from the ink tube set ITS, and the second ink supply tube connection part ISC2, the second ink discharge tube connection part IDC2, and the flow path structures related to these are omitted from the head mechanism 40.

[0234] The head system 100 of the above embodiment is a circulation type head system that includes a structure for discharging ink not ejected in the head mechanism 40 to the outside of the head system 100, but is not limited to this. Each configuration related to discharging ink may be omitted from the head system 100 of the above embodiment.

[0235] The above describes the embodiment and modified examples using as an example a case where an image is formed on a medium PM by ejecting ink from the head system 100. The head system 100 may be a liquid ejection system that ejects any liquid for forming an image, and the medium PM on which the image is formed may be, for example, paper, cloth, resin, etc. The head system 100 may also be used as a head system for a serial head type printer.

[0236] The embodiments described in this specification are illustrative in all respects and should not be considered as limiting. For example, the number, configuration, etc. of the head systems 100 in the printer 1000 may be changed. The number of colors that the printing device 1000 can print simultaneously is not limited, and the printing device 1000 may be configured to be capable of only monochrome printing. In addition, the number, arrangement, etc. of the individual flow channels iCH may be changed as appropriate. Furthermore, the technical features described in each embodiment and modified example may be combined with each other.

[0237] As long as the characteristics of the present invention are maintained, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0238] 10. Chassis 20 Preheating channel 30 Subtank 40 Head mechanism 50 Refrigerant distribution mechanism 51 Refrigerant supply manifold 53 Refrigerant discharge manifold 60 Cooling mechanism 70 Relay board 80 Control board section 600 Control section 900 Liquid dispensing device 1000 Printers ITS Ink Tube Set

Claims

1. Multiple heads and a sub-tank connected to each of the plurality of heads and distributing liquid to each of the plurality of heads; a supply flow path for supplying the liquid to the subtank; a heater for heating the liquid in the supply flow path; a housing that houses the sub-tank, the supply flow path, and the heater, The supply flow path is defined inside a flow path member that is an elongated block-shaped member having a longitudinal direction, The heater is located on one surface of the flow path member, the supply flow path includes a first portion having an upstream end located at one end side of the flow path member in the longitudinal direction and a downstream end located at the other end side of the flow path member in the longitudinal direction, a second portion having an upstream end located at the other end side of the flow path member in the longitudinal direction and a downstream end located at one end side of the flow path member in the longitudinal direction, and a third portion connecting the downstream end of the first portion and the upstream end of the second portion, A head system in which the first portion and the second portion are aligned in an orthogonal direction that is orthogonal to a direction in which the heater and the flow path member are aligned and is also orthogonal to a longitudinal direction of the flow path member.

2. A head system as described in claim 1, wherein a cross-section of the supply flow path along a plane perpendicular to the direction in which the supply flow path extends has a longitudinal shape.

3. 3. The head system of claim 1, wherein the supply passage rises gradually from the upstream end of the first portion to the downstream end of the second portion.

4. A head system described in any one of claims 1 to 3, wherein the heater is provided in an area other than the longitudinal center portion of the flow path member.

5. the sub-tank is disposed above the plurality of heads, a plurality of conduits, each of which fluidly connects the sub-tank to one of the plurality of heads; 5. The head system according to claim 1, wherein the flow path member is disposed between the sub-tank and the plurality of heads in the vertical direction.

6. a surface of the flow path member opposite to a surface thermally connected to the heater faces the plurality of pipes, 6. The head system according to claim 5, further comprising a planar member formed of a high emissivity material having a higher emissivity than a material of the flow path member, on the opposite surface.

7. The head system according to any one of claims 1 to 6, further comprising a heat dissipation member thermally connected to the heater, on a surface of the heater opposite to a surface thermally connected to the flow path member.

8. The plurality of heads are aligned along a first direction, the sub-tank has a storage portion extending in the first direction, 8. The head system according to claim 1, further comprising a sub-tank heater that heats the liquid in the reservoir.

9. The head system according to claim 8 , wherein a length of the portion of the supply flow path that is heated by the heater is greater than a length of the storage portion in the first direction.

10. 10. The head system according to claim 8, wherein a cross-sectional area of ​​a portion of the supply flow passage that is heated by the heater is smaller than a cross-sectional area of ​​a cross section of the storage portion that is perpendicular to the first direction.

11. the supply flow path is made of metal, the sub-tank has a metal plate disposed at a lower portion of the sub-tank and defining a bottom of the storage portion; 11. The head system according to claim 8, wherein the sub-tank heater is thermally connected to a lower surface of the metal plate.

12. 12. The head system according to claim 11, wherein the sub-tank further comprises a body portion that defines a side wall of the storage portion, and the body portion has a thermal conductivity lower than that of the metal plate.

13. the sub-tank has a plurality of openings spaced apart from each other in the first direction, and is configured to supply the liquid to one of the plurality of heads from each of the plurality of openings; 13. The head system according to claim 8, wherein a downstream end of the supply flow path is connected to an end of the sub-tank in the first direction.

14. A head system according to any one of claims 8 to 13, A liquid ejection apparatus including a control unit for controlling the head system, The control unit controls the head system so that an amount of increase in temperature of the liquid caused by the heater is greater than an amount of increase in temperature of the liquid caused by the sub-tank heater.

15. the head system further includes a head heater provided in each of the plurality of heads; The liquid ejection device according to claim 14 , wherein the control unit controls the head system so that an amount of increase in temperature of the liquid caused by the heater is greater than an amount of increase in temperature of the liquid caused by the head heater.

16. A liquid ejection device as described in claim 15, wherein the temperature of the liquid flowing into the subtank is T1, the temperature of the liquid flowing out of the subtank is T2, and the temperature of the liquid ejected from the multiple heads is T3, and the control unit controls the head system so that T3>T2 or T3>T1.

17. The liquid ejection apparatus according to claim 16 , wherein the control unit controls the head system so that T2>T1.

18. A liquid ejection device described in any one of claims 14 to 17, wherein the control unit sets the temperature of the heater to above the target temperature when the temperature of the liquid flowing out of the subtank is lower than a target temperature, and lowers the temperature of the heater to below the target temperature after the temperature of the liquid flowing out of the subtank becomes above the target temperature.

19. A liquid ejection device according to any one of claims 14 to 18, a transport device that transports a medium toward the plurality of heads.

20. A liquid supplying method for supplying liquid to a plurality of heads in a head system, comprising the steps of: While supplying the liquid to a subtank through a supply flow path, a control unit that controls the head system controls a heater that heats the liquid in the supply flow path to increase the temperature of the liquid by ΔT1° C.; Next, a subtank heater that heats the liquid in the subtank is controlled by the control unit to increase the temperature of the liquid in the subtank by ΔT2° C., which is smaller than ΔT1° C.; and then supplying the liquid from the sub-tank to each of the plurality of heads.

21. The liquid supply method according to claim 20, further comprising controlling a head heater provided in each of the plurality of heads by the control unit to increase the temperature of the liquid in each of the plurality of heads by ΔT3°C which is smaller than ΔT1°C.

22. The liquid supply method according to claim 21, wherein the temperature of the liquid flowing into the subtank is T1, the temperature of the liquid flowing out of the subtank is T2, and the temperature of the liquid ejected from the multiple heads is T3, and the control unit controls the head heater and the subtank heater to raise the temperature of the liquid so that T3 > T2, or the control unit controls the head heater and the heater to raise the temperature of the liquid so that T3 > T1.

23. The liquid supply method according to claim 22, wherein the control unit controls the sub-tank heater and the heater to increase the temperature of the liquid so that T2>T1.

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