Liquid discharge head and liquid discharge device

Abstract

To enhance cooling effect by a refrigerant flow passage.SOLUTION: A liquid discharge head 100 comprises a head tank 102 and a second frame member 103 having different linear expansion coefficients provided to contact each other, and a temperature adjustment-liquid flow passage 12 passing through the second frame member 103. The temperature adjustment-liquid flow passage 12 has a first temperature adjustment pool 106 and a second temperature adjustment pool 107 which are protruding parts protruding in a direction different from a feeding direction of temperature adjustment liquid. In a feeding direction of the temperature adjustment liquid in the temperature adjustment-liquid flow passage 12, the first temperature adjustment pool 106 is formed at either of an upstream side and a downstream side of a contact surface on which the head tank 102 contacts the second frame member 103, and the second temperature adjustment pool 107 is formed at the other side of the upstream side and the downstream side of the contact surface C.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] In a liquid ejection head, for example, a piezoelectric actuator is driven to generate pressure in an individual liquid chamber, causing the ink in the individual liquid chamber to be ejected from the nozzle. During this process, the piezoelectric element in the piezoelectric actuator generates heat, causing the temperature inside the liquid ejection head to rise.

[0003] In response to this, there is already an invention of a liquid ejection head that prevents the temperature from rising by providing a coolant flow path through which cooling water flows as a coolant (for example, Patent Document 1 (Japanese Patent No. 7196569)). Summary of the Invention [Problem to be solved by the invention]

[0004] Providing a refrigerant flow path can provide a certain level of cooling effect for the liquid ejection head. However, in a configuration in which a first member and a second member with different linear expansion coefficients are stacked inside the liquid ejection head, there is a problem in that cracks occur in the members due to the difference in thermal contraction after thermal expansion between the first member and the second member.

[0005] An object of the present invention is to improve the cooling effect of the refrigerant flow path. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a liquid ejection head comprising a first member and a second member having different linear expansion coefficients and arranged in contact with each other, and a refrigerant flow path passing through the inside of the second member, wherein the refrigerant flow path has a first protrusion and a second protrusion that protrude in a direction different from the refrigerant flow direction, and the first protrusion is arranged on one of the upstream and downstream sides of a contact surface where the first member and the second member come into contact in the refrigerant flow path, and the second protrusion is arranged on the other of the upstream and downstream sides of the contact surface. [Effects of the Invention]

[0007] In the present invention, the cooling effect of the refrigerant flow path can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating the configuration of a main part of an inkjet recording apparatus equipped with a liquid ejection head according to an embodiment of the present invention. [Figure 2] FIG. 1 is a plan view of an inkjet recording apparatus. [Figure 3] FIG. 2 is an exploded perspective view showing a simple configuration of a head main body provided in the liquid ejection head. [Figure 4] FIG. 2 is a plan view showing each member of the head main body from the nozzle surface side. [Figure 5] FIG. 2 is a plan view showing each member of the head body from the laminated piezoelectric element side. [Figure 6] 4 is a cross-sectional view of the liquid ejection head, corresponding to the cross section AA' in FIG. 3. [Figure 7] FIG. 7 is a cross-sectional view taken along line BB' in FIG. [Figure 8] A figure showing the arrangement of the temperature control liquid flow path in the first frame member, where (a) is an oblique view showing the liquid ejection head, (b) is an E-E' cross-sectional view of (a), and (c) is a plan view showing a simplified view of the temperature control liquid flow path. [Figure 9] FIG. 10 is a cross-sectional view showing a modified example of the liquid ejection head. [Figure 10]FIG. 10 is a cross-sectional view showing a modified example of the liquid ejection head. [Figure 11] FIG. 10 is a cross-sectional view showing a modified example of the liquid ejection head. [Figure 12] FIG. 10 is a diagram illustrating the configuration of a main part of another example of a liquid ejection device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted.

[0010] First, the basic configuration of an inkjet recording apparatus (liquid ejection apparatus) according to one embodiment of the present invention will be described. Fig. 1 is a diagram showing the configuration of the main parts of the inkjet recording apparatus. Fig. 2 is a plan view showing the configuration of the main parts.

[0011] The inkjet recording apparatus 1 according to the first embodiment is a serial-type inkjet recording apparatus. A carriage 433 is supported by main and sub guide rods 431 and 432, which are horizontally supported on left and right side plates 421A and 421B, allowing it to move back and forth in the main scanning direction (the direction of the arrow). This carriage 433 is equipped with two liquid ejection heads 100A and 100B, each of which integrates a head main body 101 and a head tank 102, a sub-tank that supplies ink (liquid) to the head main body 101. The head main body 101 has a nozzle array (the longitudinal direction of the nozzle array) consisting of multiple nozzles (ejection holes) aligned in a sub-scanning direction (the longitudinal direction of the liquid ejection head) perpendicular to the main scanning direction. The head main body 101 is mounted with the liquid ejection direction, or the extension direction of the nozzles, perpendicular to the main scanning direction and the sub-scanning direction, pointing downward in the vertical direction. However, this does not have to be strictly vertical. Hereinafter, the liquid ejection head 100A or the liquid ejection head 100B will also be simply referred to as the liquid ejection head 100.

[0012] Each of the two liquid ejection heads 100A, 100B has two nozzle rows. The head body 101 of one liquid ejection head 100A ejects black (K) ink droplets from each nozzle of one nozzle row, and ejects cyan (C) ink droplets from each nozzle of the other nozzle row. The head body 101 of the other liquid ejection head 100B ejects magenta (M) ink droplets from each nozzle of one nozzle row, and ejects yellow (Y) ink droplets from each nozzle of the other nozzle row.

[0013] Although the inkjet recording apparatus according to the first embodiment uses two liquid ejection heads to eject ink droplets of four colors, it is also possible to arrange four nozzle rows in one liquid ejection head and eject ink droplets of four colors from one liquid ejection head. Furthermore, the term "integrated" in the liquid ejection heads 100A and 100B means that the head main body 101 and the head tank 102 are fixed to each other by a fastening member or adhesive, either directly or via a filter member or the like. Alternatively, it means that the head main body 101 and the head tank 102 are connected to each other by a tube or the like.

[0014] Main tanks 410k, 410c, 410m, and 410y, which are liquid cartridges for the respective colors, are detachably mounted in a cartridge holder 404 on the apparatus main body side. Then, ink of each color is sent from the main tank 410 of each color to the head tank 102 of each liquid ejection head 100A, 100B via supply tubes 436 of each color by a liquid sending unit 424 including a liquid sending pump 438c.

[0015] The inkjet recording apparatus according to the first embodiment includes a paper feed unit for feeding recording sheets 442 as recording materials stacked on a sheet stacking unit 441 of a paper feed tray 402. The paper feed unit includes a paper feed roller 443 that separates and feeds the recording sheets 442 one by one from the sheet stacking unit 441, and a separation pad 444 that faces the paper feed roller 443.

[0016] The inkjet recording apparatus 1 according to the first embodiment also includes a guide 445 for transporting and guiding the fed recording sheet 442, a counter roller 446, a transport guide member 447, and a presser member 448 having a tip pressure roller 449. Furthermore, the inkjet recording apparatus 1 also includes a transport belt 451, which is a transport means for suctioning the transported recording sheet 442 and transporting it to a position facing the head main body 101 of the liquid ejection head 100.

[0017] The conveyor belt 451 is an endless belt that is stretched between a conveyor roller 452 and a tension roller 453 and rotates in the belt conveyance direction (sub-scanning direction). This conveyor belt 451 is an electrostatic conveyor belt that is charged by a charging roller 456 that serves as a charging means. However, the conveyor belt 451 may also be a conveyor belt that is adsorbed by air suction. Alternatively, the conveyor means may not use a conveyor belt but may be one that conveys by rollers.

[0018] A separation claw 461 for separating the recording sheet 442 from the conveyor belt 451, a paper discharge roller 462 and a paper discharge roller 463 are provided downstream of the tension roller 453 around which the conveyor belt 451 is wound, and a paper discharge tray 403 is provided below the paper discharge roller 462. A duplex unit 471 is detachably attached to the rear of the device body. This duplex unit 471 takes in the recording sheet 442 returned by the reverse rotation of the conveyor belt 451, turns it over, and feeds it again between the counter roller 446 and the conveyor belt 451. The upper surface of this duplex unit 471 serves as a manual feed tray 472. Furthermore, a maintenance and recovery mechanism 481 for maintaining and recovering the state of the nozzles of the head main body 101 of the liquid ejection heads 100A and 100B is arranged in a non-printing area on one side of the scanning direction of the carriage 433.

[0019] The maintenance and recovery mechanism 481 is equipped with caps 482a and 482b for capping the nozzle surface of the head main body 101. The maintenance and recovery mechanism 481 is also equipped with a blade member 483 for wiping the nozzle surface. The maintenance and recovery mechanism 481 is also equipped with an idling receiver 484 that receives ink when idling is performed to eject ink that does not contribute to image formation in order to discharge thickened ink. In addition, an idling receiver 488 is arranged in the non-printing area on the other side of the scanning direction of the carriage 433, which receives ink when idling is performed during image formation, etc. The idling receiver 488 is equipped with an opening 489 that is aligned with the nozzle arrangement direction of the head main body 101.

[0020] In the inkjet recording apparatus according to the first embodiment, recording sheets 442 are separated and fed one by one from a paper feed tray 402. The recording sheets 442 fed upward in a substantially vertical direction are guided by a guide 445 and conveyed while being sandwiched between a conveyor belt 451 and a counter roller 446. Furthermore, the leading edge of the recording sheet 442 is guided by a conveyor guide 437, and is pressed against the conveyor belt 451 by a leading edge pressure roller 449, thereby changing the conveying direction by approximately 90 degrees. When the recording sheet 442 is fed onto the charged conveyor belt 451, the recording sheet 442 is attracted to the conveyor belt 451, and is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 451. Then, by driving the head bodies 101 of the liquid ejection heads 100A and 100B in accordance with an image signal while moving the carriage 433, ink is ejected onto the stationary recording sheet 442 to record one line of an image. Then, after conveying the recording sheet 442 by a predetermined distance, the next line of image formation is performed. Upon receiving a recording end signal or a signal indicating that the rear end of the recording sheet 442 has reached the recording area, the recording operation is terminated and the recording sheet 442 is discharged to the discharge tray 403.

[0021] Fig. 3 is an exploded perspective view showing a simplified configuration of the head main body 101. Fig. 4 is an exploded plan view showing each plate-like member of the head main body 101 from the nozzle side. Fig. 5 is an exploded plan view showing each plate-like member of the head main body 101 from the laminated piezoelectric element side. Note that Figs. 3 to 5 only show one of the two nozzle rows provided in the head main body 101.

[0022] In these figures, the nozzles 2A, which are multiple ejection holes, are formed in a nozzle plate 2, which serves as an ejection hole forming member. The nozzle plate 2 is made of, for example, a stainless steel plate. The processing accuracy of the slits (through holes) that become the nozzles 2A has a significant effect on the ink ejection characteristics of the head main body 101. In order to minimize variations in dimensional accuracy between the multiple nozzles 2A, the multiple slits in the nozzle plate 2 must be processed with high precision. For this reason, the multiple slits in the nozzle plate 2 are formed by methods such as press processing, laser processing, and nickel electroforming.

[0023] The pressure generating chambers 3, which are multiple individual liquid chambers, and the multiple individual supply channels 4, which individually communicate with these chambers, have their sides formed by slits provided in the flow channel plate 5. Each of the multiple individual supply channels 4 individually connects a common liquid chamber 10, which is part of the liquid flow channel, with the multiple pressure generating chambers 3, and has a large diameter portion (reference numeral 4a in FIG. 6) that is relatively large in size in the plate surface direction, and a small diameter portion (reference numeral 4b in FIG. 6). The flow channel resistance of the small diameter portion 4b controls the amount of ink that flows from the common liquid chamber 10 to the pressure generating chambers 3.

[0024] Each of the multiple pressure generating chambers 3 is connected to one of the multiple nozzles 2A provided in the nozzle plate 2. The slits provided in the flow path plate 5, which serves as an individual liquid chamber forming member and an individual supply path forming member, for forming the individual supply paths 4 and pressure generating chambers 3 are processed by precision pressing.

[0025] The diaphragm plate 8 is formed with a diaphragm membrane 7 for efficiently transmitting the displacement of the piezoelectric actuator 21 to the pressure generating chamber 3, and individual supply openings 6 located at the boundary between the common liquid chamber 10 and the multiple individual supply paths 4. The diaphragm membrane 7 is formed from a solid area of ​​the base material of the diaphragm plate 8 and has the same thickness as the base material. The areas of the diaphragm plate 8 that are thicker than the diaphragm membrane 7 are formed from the base material and portions that are electroplated onto the base material by electroforming. The individual supply openings 6 are through openings that connect the inside of the individual supply paths 4 with the inside of the common liquid chamber 10.

[0026] A large rectangular through-opening is formed in the first frame member 11 serving as a flow path member. This opening constitutes an actuator insertion portion 9 for inserting a piezoelectric actuator 21, which will be described later. A large rectangular opening is also formed for forming a common liquid chamber 10. Furthermore, a large rectangular opening 11a is also formed on the side of the first frame member 11 opposite to the side where the common liquid chamber 10 opens, for forming a temperature adjustment liquid flow path 12, which is a refrigerant flow path. The temperature adjustment liquid flow path 12 is formed adjacent to the common liquid chamber 10 and is located on the opposite side of the common liquid chamber 10 from the flow path plate 5 in which the pressure generating chambers 3 are formed. In this embodiment, the temperature adjustment liquid flow path 12 is disposed vertically above the common liquid chamber 10.

[0027] The partition plate 13 is used to cover the opening of the temperature control liquid flow path 12 in the first frame member 11 and seal the temperature control liquid flow path 12. The partition plate 13 has through holes formed therein that form ink inlet and outlet paths 14. The ink inlet and outlet paths 14 are paths that guide ink sent from the head tank 102 to the common liquid chamber 10 and discharge ink that has passed through the common liquid chamber 10 from the common liquid chamber 10. The partition plate 13 also has through holes 13a that form temperature control liquid inlet and outlet paths 15. The temperature control liquid inlet and outlet paths 15 are paths that introduce and discharge the temperature control liquid, which is a refrigerant, into and from the temperature control liquid flow path 12. Cutting and the like can be used as a method for forming these through openings and through holes.

[0028] The rectangular through-opening for constituting the actuator insertion portion 9 is formed to accommodate the entire piezoelectric actuator 21, but rigidity may be increased by providing multiple partition walls to individually accommodate multiple piezoelectric elements 19 of the piezoelectric actuator 21. Increasing rigidity can reduce defects due to the random cause of crosstalk (mutual interference between channels (combinations of nozzles 2A, pressure generating chambers 3, individual supply paths 4, and piezoelectric elements 19)).

[0029] The piezoelectric actuator 21 includes a plurality of piezoelectric elements 19, each corresponding to a corresponding one of the nozzles 2A, and a fixing member 20 for fixing the piezoelectric elements. One end of each piezoelectric element 19 is fixed to one end of the fixing member 20 using an adhesive, and the other end of each piezoelectric element 19 is bonded to the diaphragm film 7. Each piezoelectric element 19 is connected to an individual electrode provided for each element and a common electrode shared by all elements. Individual switching elements for individually controlling the on / off of power are connected to the individual electrodes. These switching elements are disposed on a flexible printed circuit board 22. This electrode configuration allows each of the plurality of piezoelectric elements 19 to be individually driven (displaced), and this individual driving can individually change the ink pressure in each of the plurality of pressure-generating chambers 3. Ink droplets are ejected from the nozzles 2A connected to the pressure-generating chambers 3, whose ink pressure is increased by the displacement of the piezoelectric elements 19.

[0030] FIG. 6 is a cross-sectional view of the liquid ejection head 100, corresponding to the cross section AA' in FIG.

[0031] 6, the liquid ejection head 100 has a head main body 101, a head tank 102 as a first member, and a second frame member 103. The head tank 102 is a liquid storage member that stores ink (liquid).

[0032] The head tank 102 has an internal storage space for storing ink. The second frame member 103 forms part of the outer circumferential surface of the liquid ejection head 100.

[0033] The head tank 102 of this embodiment is made of a resin material such as high density polyethylene, and its linear expansion coefficient is 10×10 ―5 [ / K] or more. The second frame member 103 of this embodiment is made of a metal material, and its linear expansion coefficient is set to 2×10 ―5 [ / K] or less. The second frame member 103 is made of, for example, SUS. By making the head tank 102 out of a resin material, the cost of the head tank 102 can be reduced. However, the material of the head tank 102 is not limited to this.

[0034] Ink introduced from the head tank 102 flows into the common liquid chamber 10 via the ink inlet / outlet flow path 14. The large diameter portions 4a of the individual supply paths 4 of each channel are connected to this common liquid chamber 10 via the individual supply openings 6. Ink that has entered the large diameter portions 4a of the individual supply paths 4 from the common liquid chamber 10 enters the small diameter portions 4b and is directed toward the pressure generating chambers 3 while being subjected to flow path resistance.

[0035] In the head main body 101 of this embodiment, the piezoelectric element generates heat to drive the piezoelectric actuator 21 for ink ejection. The generated heat heats the ink to be ejected via the head structure (first frame member 11, etc.) that constitutes the head main body 101. To eject ink faster, the piezoelectric actuator 21 must vibrate at a high frequency. This generates heat, which changes the ink temperature. The ink temperature also changes with changes in ambient temperature. Such temperature changes cause changes in the ink viscosity and surface tension, which in turn changes the ink ejection speed and ejection volume (ejection amount), adversely affecting recording quality. Note that this problem is not limited to the piezo-based method used in this embodiment, but also occurs in methods using heating elements and electrostatic types.

[0036] The cooling configuration for cooling the components and ink inside the liquid ejection head will be described below with reference to Figure 7. Figure 7 is a cross-sectional view taken along line BB' in Figure 6. However, some parts such as the common liquid chamber have been omitted.

[0037] As shown in FIG. 7, the head tank 102 and the second frame member 103 are fastened together with screws 105. Surface C in FIG. 7 is the contact surface C where the head tank 102 and the second frame member 103 come into contact. In FIG. 7, the contact surface C is a flat surface parallel to the longitudinal direction, but it may also have projections and recesses. Furthermore, a sheet-like member, for example, may be interposed between the head tank 102 and the second frame member 103, so that the two are in indirect contact with each other. In this case, the contact surface C may be any surface of the interposed member.

[0038] A through-hole 103a that constitutes part of the temperature control liquid flow path 12 is formed in the second frame member 103. One end of the through-hole 103a communicates with the through-hole 13a in the partition plate 13 and with the opening 11a in the first frame member 11. A through-hole 102a is also formed in the head tank 102. The other end of the through-hole 103a in the second frame member 103 communicates with the through-hole 102a in the head tank 102.

[0039] Furthermore, a temperature control flow path member 104 as a refrigerant flow path member is attached to the other end of the through hole 103a of the frame member 103, passing through the through hole 102a of the head tank 102. The temperature control flow path member 104 is a hollow, approximately cylindrical member, and is made of, for example, a metal material.

[0040] By attaching the temperature control flow path member 104 to the other end of the through hole 103a of the frame member 103, the internal space 104a of the temperature control flow path member 104 and the through hole 103a of the frame member 103 are connected. This forms a part of the temperature control liquid flow path 12 that continues from the internal space 104a, through the through hole 103a, through the through hole 13a, and through the opening 11a. In this manner, the temperature control liquid flow path 12 of this embodiment forms a flow path that flows from the head tank 102 side, passing through the contact surface C, to the second frame member 103 side. The directions indicated by arrows D1 and D2 in FIG. 7 are the directions in which the temperature control liquid is sent through the temperature control liquid flow path 12. The temperature control liquid flow path 12 is connected on the upstream side of the internal space 104a and the downstream side of the opening 11a, forming a circulation path within the liquid ejection head or liquid ejection device. The branch path 12a, which is part of the temperature adjustment liquid flow path 12, is a portion of the temperature adjustment liquid flow path 12 that is adjacent to the common liquid chamber 10 within the first frame member 11 and extends in the longitudinal direction of the first frame member 11. Furthermore, two of these branch paths 12a are provided for each head body 101, for a total of four.

[0041] In this embodiment, by circulating the temperature-regulating liquid within the temperature-regulating liquid flow path 12, heat exchange occurs between the components within the liquid ejection head 100 and the temperature-regulating liquid, thereby cooling the liquid ejection head. This suppresses temperature rise within the liquid ejection head due to heat generation by the piezoelectric element, as described above. In particular, as shown in FIG. 6, by locating the temperature-regulating liquid flow path 12 adjacent to the common liquid chamber 10 through which ink passes and extending longitudinally within the first frame member 11 (see FIG. 5), the liquid ejection head can be efficiently cooled. That is, heat generated by the piezoelectric element is transferred from the pressure generating chambers 3 and the individual supply paths 4 to the common liquid chamber 10, thereby heating the ink within the common liquid chamber 10. Regarding the overall heat distribution of the ink within the head main body 101, the ink temperature tends to be higher vertically above the common liquid chamber 10 due to thermal convection. In this embodiment, the head main body 101 is mounted with the nozzle plate 2 facing vertically downward, and the liquid ejection direction is directed vertically downward. Therefore, the temperature adjustment liquid flow path 12 in this embodiment is disposed vertically above the common liquid chamber 10. Therefore, according to this embodiment, heat from the vertically above the common liquid chamber 10 can be exchanged with the refrigerant in the temperature adjustment liquid flow path 12, and a head main body 101 with good cooling efficiency can be realized.

[0042] However, in a configuration in which the head tank 102 and the second frame member 103, which have different linear expansion coefficients, are in contact with each other, as in this embodiment, the difference in thermal contraction between them can cause problems such as peeling between the two, peeling of the sealant, and cracking of the components. That is, when the head tank 102 is heated, it expands more than the second frame member 103. As a result, when these components cool and contract over time after heating, stress is generated between the two, resulting in the peeling and cracking. In particular, in this embodiment, the metal second frame member 103 is in contact with the resin head tank 102, and the large difference in linear expansion coefficients between them exacerbates these problems. Therefore, a configuration in which a temperature control liquid is simply flowing through the temperature control liquid flow path 12 does not provide a sufficient cooling effect.

[0043] In contrast, in this embodiment, temperature-controlled pools serving as protrusions are provided on both the upstream and downstream sides of the contact surface C between the head tank 102 and the second frame member 103. Specifically, as shown in FIG. 7, the temperature-controlled flow path member 104 has a portion with a larger diameter, and this larger diameter portion forms a first temperature-controlled pool 106 serving as a first protrusion. The first temperature-controlled pool 106 in this embodiment is provided inside the head tank 102. Alternatively, the first temperature-controlled pool 106 may be provided adjacent to the head tank 102 outside the head tank 102. The opening 11a of the first frame member 11 has a portion extending in the opposite direction to the branch path 12a, and this portion forms a second temperature-controlled pool 107 serving as a second protrusion. In the flow direction of the temperature-controlled liquid in the temperature-controlled liquid flow path 12, the first temperature-controlled pool 106 is provided on one side, that is, upstream of the contact surface C, and the second temperature-controlled pool 107 is provided on the other side, that is, downstream of the contact surface C. However, the flow direction of the temperature control liquid may be opposite to that shown in FIG.

[0044] The temperature control pool as a protruding portion is a portion of the space constituting the temperature control liquid flow path 12 that protrudes (bulges) in a direction different from the temperature control liquid flow direction relative to other portions (e.g., its surroundings) of the temperature control liquid flow path 12. For example, the first temperature control pool 106 is a portion that protrudes in each direction on a plane perpendicular to the temperature control liquid flow direction D1, and the second temperature control pool 107 is a portion that protrudes in the opposite direction to the temperature control liquid flow direction D2 (also a portion that protrudes in a direction different from the flow direction D1). The temperature control liquid flow direction is the direction in which the temperature control liquid flows along the temperature control liquid flow path 12 when no temperature control pool is provided, or the main extension direction of the temperature control liquid flow path 12. Furthermore, if the temperature control liquid flow path 12 passes through the contact surface C at multiple locations, it is sufficient to provide a temperature control pool upstream and downstream of any of the contact positions. In particular, in this embodiment, the first temperature-controlled pool 106 on the upstream side is provided inside (or adjacent to) the head tank 102, and the second temperature-controlled pool 107 on the downstream side is provided inside the first frame member 11. Alternatively, the second temperature-controlled pool 107 can be provided upstream of the first frame member 11.

[0045] In this embodiment, providing a temperature-controlling pool in the temperature-controlling liquid flow path 12 disrupts the flow of the temperature-controlling liquid within the temperature-controlling liquid flow path 12, generating turbulence in the temperature-controlling pool. This allows the temperature-controlling liquid to remain in the temperature-controlling pool, enabling more efficient heat exchange between the temperature-controlling liquid and each component within the liquid ejection head. In particular, providing temperature-controlling pools upstream and downstream of the contact surface C generates turbulent flow of the temperature-controlling liquid on both the upstream and downstream sides of the contact surface C, sandwiching the contact surface C where stress is generated due to thermal contraction. This reduces stress at and near the contact surface C, preventing separation between the head tank 102 and the second frame member 103, peeling of the sealant therebetween, or cracking of these components. In particular, providing a second temperature-controlling pool 107 within the first frame member 11, which is provided with a common liquid chamber and located near the piezoelectric element, allows for efficient cooling within the liquid ejection head. Furthermore, by providing the first temperature control pool 106 inside the head tank 102 or adjacent to the head tank 102 in the temperature control liquid flow path 12, the head tank 102 can be cooled efficiently and thermal expansion of the head tank 102 can be suppressed.

[0046] In particular, as in this embodiment, the difference in the linear expansion coefficient between the head tank 102 and the second frame member 103 that are in contact with each other is 8×10 ―5 When the thickness is large, such as [ / K] or more, the above-mentioned problems of peeling and cracking become particularly noticeable, and it is therefore preferable to apply the configuration of the liquid ejection head of this embodiment.

[0047] In this embodiment, the linear expansion coefficient can be measured using, for example, JIS Z 2285 (Method for measuring the linear expansion coefficient of metallic materials) or JIS K7197:2012, a method for measuring the linear expansion coefficient by thermomechanical analysis of plastics. Furthermore, the measurement method specified in JIS can be appropriately adopted depending on the target member.

[0048] Figure 8 shows the arrangement of the temperature control liquid flow path 12 in the first frame member 11, where (a) is an oblique view showing the liquid ejection head, (b) is a cross-sectional view taken along line E-E' of (a), and (c) is a plan view showing a simplified view of the temperature control liquid flow path.

[0049] 8(a), the temperature adjustment liquid flow path passes through the inside of temperature adjustment flow path members 104A and 104B on the inlet and outlet sides, respectively, of the liquid ejection head 100 (first frame member 11). In other words, the temperature adjustment flow path members 104A and 104B form the inlet and outlet portions of the temperature adjustment liquid flow path with respect to the first frame member 11.

[0050] As shown in FIG. 8(b), each branch path 12a of the temperature adjustment liquid flow path is provided adjacent to each common liquid chamber 10.

[0051] As shown in FIG. 8(c), on a plane perpendicular to the direction of liquid ejection from the nozzles on the paper surface of FIG. 8(c), the temperature adjustment flow path members 104A and 104B, which are the inlet and outlet portions of the temperature adjustment liquid flow path 12 with respect to the first frame member 11, are arranged at diagonal positions relative to the center position of the first frame member 11. This allows the temperature adjustment liquid flow path 12 to be arranged evenly in the first frame member 11, as shown in FIG. 8(c). This makes the temperature distribution in the first frame member 11 (or the liquid ejection head 100) more uniform, and prevents uneven stress generation in the first frame member 11. This prevents peeling of the head tank 102 and the second frame member 103 or their seals, as well as cracking of these components. However, they do not necessarily have to be arranged at diagonal positions.

[0052] Next, modified examples of the liquid ejection head will be described in order.

[0053] In the embodiment shown in FIG. 9 , a resistance member 108 is provided in the temperature control liquid flow path 12. The resistance member 108 is provided across the contact surface C on both sides of the head tank 102 and the second frame member 103. The resistance member 108 in this embodiment is a static mixer. However, any member that resists the flow of the temperature control liquid in the temperature control liquid flow path 12 may be used. For example, a longitudinal member having a mesh or slits may be disposed across the contact surface C in the vertical direction in FIG. 9 . By providing the resistance member 108, the flow of the temperature control liquid in the temperature control liquid flow path 12 can be impeded, generating turbulence and enhancing the cooling effect of the temperature control liquid. In particular, by providing the resistance member 108 on the head tank 102 and second frame member 103 side across the contact surface C, the head tank 102 and the second frame member 103 can be efficiently cooled. This further reduces peeling of the head tank 102 and the second frame member 103 and their seals, as well as cracking of these components.

[0054] In the embodiment shown in FIG. 10, a single first temperature-controlled pool 106 is provided across the contact surface C, extending from both the upstream and downstream sides thereof, i.e., from the head tank 102 to the second frame member 103. This generates turbulence in the temperature-controlled liquid flow path 12, particularly near the contact surface C where peeling and cracking due to thermal contraction occur, thereby achieving a greater cooling effect from the temperature-controlled liquid. This effectively prevents the peeling and cracking. Note that, when a single temperature-controlled pool is provided across the contact surface C on both the upstream and downstream sides thereof, as in this embodiment, a second temperature-controlled pool is not required. However, providing a second temperature-controlled pool 107 is more preferable because it allows for efficient cooling of the first frame member 11, in which the common liquid chamber is provided, and its vicinity.

[0055] In the embodiment shown in FIG. 10 , adhesive 109 is applied as a coating agent to the outer periphery of the contact surface C between the head tank 102 and the second frame member 103. In this embodiment, a metallic adhesive is used as the coating agent. By providing the coating agent at the contact surface C, i.e., the boundary between the head tank 102 and the second frame member 103, a portion of the heat near the contact surface C can be absorbed by the adhesive 109, thereby suppressing temperature increases in the head tank 102 and the second frame member 103. This further suppresses peeling of the head tank 102 and the second frame member 103 or their sealants, as well as cracking of these components. However, the coating agent is not limited to this, and may be a sealant that seals the boundary between the head tank 102 and the second frame member 103, or a coating agent that simply increases heat capacity.

[0056] 11, an adhesive 110 is filled between the head tank 102 and the temperature control flow path member 104, i.e., in the gap of the through-hole 102a, as a coating material. This allows the adhesive 110 to absorb heat from the head tank 102, thereby suppressing a rise in temperature of the head tank 102. This further suppresses peeling of the head tank 102 and the second frame member 103, or the sealants thereon, and cracking of these members. The coating material may be a sealant or a coating material simply for increasing heat capacity.

[0057] The adhesive 109 or adhesive 110 is preferably made of a material having a higher thermal conductivity than the head tank 102. This allows the adhesive 109 or adhesive 110 to efficiently absorb heat from the head tank 102 and the like.

[0058] In Figure 10, a configuration is shown in which both the first temperature control pool 106 and adhesive 109 are provided across the contact surface C, but the configuration may also be such that adhesive 109 is provided in the embodiment shown in Figure 7, or the configuration may be combined with the resistance member 108 in Figure 9 or the adhesive 110 in Figure 11, and any combination is possible.

[0059] Next, another example of a liquid ejection device to which the above-described liquid ejection head is applied will be described with reference to Fig. 12. The liquid ejection device of Fig. 12 ejects liquid onto a web as a recording material.

[0060] An embodiment of the present invention will be described in detail below. First, as shown in FIG. 12 , a liquid ejection device 200 includes a paper feeder 201, a pretreatment liquid application / drying device 202, and a printing device 203. The paper feeder 201 supplies a web W, which is a recording material such as a roll of continuous long paper, to the pretreatment liquid application / drying device 202, which is provided downstream of the web transport path. The pretreatment liquid application / drying device 202 applies pretreatment liquid to the web W using a pretreatment liquid application unit consisting of application devices 204 and 205. The pretreatment liquid prevents bleeding and show-through of inkjet ink printed on the web W. After the pretreatment liquid is applied, the web W is dried by a drying device 206. A dancer unit 16 ensures a buffer amount for the web W between the pretreatment liquid application / drying device 202 and the printing device 203. The printing device 203 forms a desired image by ejecting ink droplets onto at least one side of the web W to which the pretreatment liquid has been applied in the pretreatment liquid application / drying device 202. The printing device 203 is equipped with first and second inkjet printer units and a reversing unit that eject ink droplets onto the front and back sides of the web W. For simplicity, FIG. 12 shows only the liquid ejection head 100 that ejects ink droplets onto one side of the web W. A post-drying device may be provided within the printing device 203 or downstream of the conveyance path of the printing device 203, and a winding device or a cutter device that cuts and stacks the web may be located further downstream. The direction indicated by the arrow in FIG. 12 is the feed direction of the web W (the conveyance direction of the recording material) and is also the direction in which a series of liquid ejection processes (printing processes) are arranged.

[0061] The above-described liquid ejection heads can also be applied to the above-described liquid ejection device 200. This can enhance the cooling effect of the refrigerant flow path. In particular, in this liquid ejection device 200, a drying device 206 is provided upstream of the liquid ejection head 100 in the liquid ejection process. Therefore, the web W transported to the liquid ejection head 100 is likely to reach a high temperature, and the liquid ejection head 100 is also likely to reach a high temperature. Therefore, it is preferable to apply the liquid ejection head 100 of the above-described embodiment.

[0062] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0063] In this specification, a "liquid ejecting device" refers to a device that includes a liquid ejection head or a liquid ejection unit and ejects liquid by driving the liquid ejection head. Liquid ejecting devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0064] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0065] For example, examples of "liquid ejecting devices" include inkjet recording devices, which are devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices), which eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0066] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0067] The term "something to which a liquid can adhere" means something to which a liquid can adhere at least temporarily, something to which the liquid adheres and sticks, something to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all things to which a liquid can adhere.

[0068] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing.

[0069] Furthermore, the term "liquid" is not particularly limited as long as it has a viscosity and surface tension that allows it to be ejected from a liquid ejection head. However, it is preferable that the viscosity of the liquid be 30 mPa·s or less at room temperature and pressure, or upon heating or cooling. More specifically, the term "liquid" refers to solutions, suspensions, emulsions, etc. containing solvents such as water or organic solvents, colorants such as dyes or pigments, functionalizing materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural dyes. These can be used for applications such as inkjet inks, surface treatment solutions, liquids for forming components of electronic devices and light-emitting elements, and resist patterns for electronic circuits, and liquid materials for 3D modeling. Specifically, "liquid" also includes inks, treatment solutions, DNA samples, resists, patterning materials, binders, modeling liquids, and solutions and dispersions containing amino acids, proteins, and calcium.

[0070] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0071] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0072] A "liquid ejection unit" is a collection of components related to the ejection of liquid, integrating functional parts and mechanisms with a liquid ejection head. For example, a "liquid ejection unit" includes a combination of a liquid ejection head and at least one of the following components: a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism.

[0073] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism fixed to each other by fastening, bonding, engaging, etc., or one held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0074] Some liquid ejection units integrate a liquid ejection head and a carriage. Other liquid ejection units integrate a liquid ejection head and a scanning movement mechanism by movably holding the liquid ejection head on a guide member that constitutes part of the scanning movement mechanism. Other liquid ejection units integrate a liquid ejection head, a carriage, and a main scanning movement mechanism. Other liquid ejection units integrate a liquid ejection head, a carriage, and a maintenance and recovery mechanism by fixing a cap member that is part of a maintenance and recovery mechanism to a carriage to which the liquid ejection head is attached. Other liquid ejection units integrate a liquid ejection head and a supply mechanism by connecting a tube to a head tank or a liquid ejection head to which a flow path component is attached. The main scanning movement mechanism also includes the guide member alone. The supply mechanism also includes the tube alone and the loading unit alone.

[0075] In addition, in the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0076] The aspects of the present invention are as follows, for example. <1> a first member and a second member having different linear expansion coefficients and provided in contact with each other; a coolant flow path passing through the inside of the second member, the refrigerant flow path has a first protrusion and a second protrusion that protrude in a direction different from a direction in which the refrigerant is sent, This liquid ejection head is characterized in that, in the refrigerant flow path, the first protrusion is provided on one of the upstream and downstream sides of the contact surface where the first member and the second member come into contact, and the second protrusion is provided on the other of the upstream and downstream sides of the contact surface. <2> The difference in the linear expansion coefficient between the first member and the second member is 8×10 ―5 [ / K] or more <1> The liquid ejection head is as described above. <3> The first member has a linear expansion coefficient of 10×10 ―5 A liquid storage member formed of a resin material of [ / K] or more, which stores the liquid to be discharged by the liquid discharge head, The second member has a linear expansion coefficient of 2×10 ―5 [ / K] Made of the following materials <2> The liquid ejection head is as described above. <4> A resistance member for obstructing the flow of the coolant is provided inside the coolant flow path on the side of the first member and the second member across the contact surface. <1> from <3> The liquid ejection head according to any one of the above is provided. <5> The protrusions are provided on the first and second members across the contact surfaces. <1> from <4> The liquid ejection head according to any one of the above is provided. <6> A coating material is applied between the first member and the second member. <1> from <5> The liquid ejection head according to any one of the above is provided. <7> a refrigerant flow path member formed inside the first member and forming a flow path adjacent to the first member in a part of the refrigerant flow path; The gap between the refrigerant flow path member and the first member is filled with a coating material. <1> from <6> The liquid ejection head according to any one of the above is provided. <8> a discharge hole forming member having a plurality of discharge holes for discharging liquid; a flow path member having a part of the refrigerant flow path and a liquid flow path, which is a flow path for the liquid to be discharged, inside the flow path member; On a plane perpendicular to the direction in which the liquid is discharged from the discharge hole, The inlet and outlet portions of the refrigerant flow path with respect to the flow path member are disposed at diagonal positions with respect to the center position of the flow path member. <1> from <7> The liquid ejection head according to any one of the above is provided. <9> <1> from <8> A liquid ejection apparatus including any one of the liquid ejection heads. <10> Ejects liquid onto the recording material <9> The liquid ejection device described above, The liquid ejection device is provided with a drying device on the upstream side of the liquid ejection head in the recording material conveyance direction. [Explanation of symbols]

[0077] 1. Inkjet recording device (liquid ejection device) 2 Nozzle plate (discharge hole forming member) 2A Nozzle (discharge hole) 10 Common liquid chamber (liquid flow path) 11 First frame member (flow path member) 12 Temperature control liquid flow path (refrigerant flow path) 12a Fork 100 Liquid ejection head 101 Head body 102 head tank (first member or liquid storage member) 103 Second frame member (second member) 104 Temperature control flow path component (refrigerant flow path component) 106 First temperature-controlled pool (first protrusion) 107 Second temperature-controlled pool (Second protrusion) 108 Resistance Member 109 Adhesives (coating agents) 110 Adhesives (coating agents) C. Contact surface between the head tank and the second frame member (contact surface between the first member and the second member) D1, D2: Temperature control liquid flow direction in the temperature control liquid flow path (refrigerant flow direction in the refrigerant flow path) [Prior art documents] [Patent documents]

[0078] [Patent Document 1] Patent No. 7196569

Claims

1. a first member and a second member having different linear expansion coefficients and provided in contact with each other; a coolant flow path passing through the inside of the second member, the refrigerant flow path has a first protrusion and a second protrusion that protrude in a direction different from a direction in which the refrigerant is sent, A liquid ejection head characterized in that, in the refrigerant flow path, the first protrusion is provided on one of the upstream and downstream sides of a contact surface where the first member and the second member come into contact, and the second protrusion is provided on the other of the upstream and downstream sides of the contact surface.

2. The difference in the linear expansion coefficient between the first member and the second member is 8×10 ―５ 2. The liquid ejection head according to claim 1, wherein the thickness is [ / K] or more.

3. The first member has a linear expansion coefficient of 10×10 ―５ A liquid storage member formed of a resin material of [ / K] or more, which stores the liquid to be discharged by the liquid discharge head, The second member has a linear expansion coefficient of 2×10 ―５ 3. The liquid ejection head according to claim 2, which is made of a material having a thickness of 1000 to 10000 mm.

4. 2. The liquid ejection head according to claim 1, wherein a resisting member for obstructing the flow of the coolant is provided inside the coolant flow path on the side of the first member and the second member across the contact surface.

5. The liquid ejection head according to claim 1 , wherein the protrusions are provided on the first and second members across the contact surface.

6. 2. The liquid ejection head according to claim 1, wherein a coating material is applied between the first member and the second member.

7. a refrigerant flow path member formed inside the first member and forming a flow path adjacent to the first member in a part of the refrigerant flow path; 2. The liquid ejection head according to claim 1, wherein a space between the coolant flow path member and the first member is filled with a coating material.

8. a discharge hole forming member having a plurality of discharge holes for discharging liquid; a flow path member having a part of the refrigerant flow path and a liquid flow path, which is a flow path for the liquid to be discharged, inside the flow path member; On a plane perpendicular to the direction in which the liquid is discharged from the discharge hole, 2. The liquid ejection head according to claim 1, wherein an inlet portion and an outlet portion of the coolant flow path with respect to the flow path member are disposed at diagonal positions relative to a center position of the flow path member.

9. A liquid ejection device comprising the liquid ejection head according to claim 1 .

10. 10. A liquid ejection apparatus according to claim 9, which ejects liquid onto a recording material, A liquid ejection device including a drying device located upstream of the liquid ejection head in a recording material conveyance direction.

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