Liquid ejecting head and liquid ejecting apparatus

Abstract

A liquid ejecting head and a liquid ejecting apparatus which heat a liquid of a liquid ejecting head without waste and efficiently by a heater are provided. The liquid ejecting head includes: a plurality of head chips which have a plurality of nozzles which eject a liquid; a holder which holds the plurality of head chips; and a heater which is a flat shape, is arranged on the holder, and heats the holder, the heater including, in a plan view, a peripheral region along an outer edge of the holder and a central region located inward of the peripheral region, a heat generation amount per unit time of the peripheral region being greater than a heat generation amount per unit time of the central region.

Description

Technical Field

[0001] This invention relates to a liquid injection head and a liquid injection device. Background Technology

[0002] Liquid ejection devices, such as inkjet printers, typically include a liquid ejection head that ejects liquids such as ink as droplets. In some liquid ejection heads, a heater is provided to heat the liquid, as in the inkjet head described in Patent Document 1.

[0003] Patent Document 1 does not disclose the distribution of heat generation per unit time of the heater. Here, a technique for heating liquids efficiently and without waste using a heater is desired.

[0004] Patent document 1: Japanese Patent Application Publication No. 2010-143109. Summary of the Invention

[0005] To address the above-mentioned issues, the preferred embodiment of the present invention relates to a liquid injection head comprising: a plurality of head chips having a plurality of nozzles for injecting liquid; a support holding the plurality of head chips; and a heater, which is planar and disposed on the support for heating the support, wherein the heater, when viewed from above, includes an outer peripheral region along the outer edge of the support and a central region located more inward than the outer peripheral region, the heat generated per unit time in the outer peripheral region being greater than the heat generated per unit time in the central region.

[0006] The liquid injection device according to a preferred embodiment of the present invention includes: a liquid injection head as described above; and a control unit that controls the driving of the heater. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating a structural example of the liquid injection device according to the first embodiment.

[0008] Figure 2 This is a perspective view of the liquid injection head and support body according to the first embodiment.

[0009] Figure 3 This is an exploded perspective view of the liquid injection head according to the first embodiment.

[0010] Figure 4 for Figure 2 Sectional view along line AA in the diagram.

[0011] Figure 5 for Figure 2 BB line section view.

[0012] Figure 6 This is a cross-sectional view showing an example of a head chip.

[0013] Figure 7 This is a bottom view of the bracket in the first embodiment.

[0014] Figure 8 This is a top view of the bracket in the first embodiment.

[0015] Figure 9 This is a plan view of the heater in the first embodiment.

[0016] Figure 10 This is a diagram illustrating the heat distribution of the heater in the first embodiment.

[0017] Figure 11 This is a diagram illustrating the heat transfer path from the heater in the first embodiment.

[0018] Figure 12 This is a diagram illustrating the heat transfer path from the heater in the first embodiment.

[0019] Figure 13 This is a diagram illustrating the heat distribution of the heater in the second embodiment.

[0020] Figure 14 This is a diagram illustrating the heat distribution of the heater in the third embodiment.

[0021] Figure 15 This is a diagram illustrating the heat distribution of the heater in the fourth embodiment.

[0022] Figure 16 This is a schematic diagram of the liquid injection head involved in Modified Example 1.

[0023] Figure 17 This is a schematic diagram of the liquid injection head involved in Modified Example 2.

[0024] Figure 18 This is a schematic diagram of the liquid injection head involved in Modified Example 3. Detailed Implementation

[0025] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the dimensions or scales of various parts in the drawings differ appropriately from actual dimensions, and some parts are shown schematically for ease of understanding. Furthermore, unless otherwise stated in the following description, the scope of the invention is not limited to these embodiments.

[0026] For ease of explanation, the following description appropriately uses intersecting X-axis, Y-axis, and Z-axis. Furthermore, in the following description, one direction along the X-axis is the X1 direction, and the opposite direction is the X2 direction. Similarly, opposite directions along the Y-axis are the Y1 and Y2 directions. Furthermore, opposite directions along the Z-axis are the Z1 and Z2 directions. Additionally, the view from the Z-axis direction is sometimes simply referred to as a "top-down view." Also, the Y1 or Y2 direction is an example of a "first direction." The X1 or X2 direction is an example of a "second direction."

[0027] Here, typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z-axis may not be a vertical axis. Furthermore, although the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, this is not a limitation, as long as they intersect at an angle, for example, between 80 and 100 degrees.

[0028] 1. First Implementation Method

[0029] 1-1. Overview of the liquid injection device

[0030] Figure 1 This is a schematic diagram illustrating a structural example of the liquid jetting apparatus 100 according to the first embodiment. The liquid jetting apparatus 100 is an inkjet printing apparatus that jets an example of a "liquid," namely ink, as droplets onto a medium M. Typically, the medium M is printing paper. However, the medium M is not limited to printing paper; for example, it can be any printing material such as a resin film or fabric.

[0031] like Figure 1 As shown, the liquid injection device 100 includes a liquid storage section 10, a control unit 20, a conveying mechanism 30, a moving mechanism 40, and a liquid injection head 50.

[0032] The liquid storage section 10 is a container for storing ink. Specific examples of the liquid storage section 10 include ink cartridges that are detachable from the liquid jetting device 100, ink pouches formed of flexible films, and ink cans that can be replenished with ink.

[0033] Although not shown, the liquid storage section 10 has multiple containers for storing inks of different types. While the inks stored in these containers are not particularly limited, examples include blue-green ink, magenta ink, yellow ink, black ink, transparent ink, white ink, and processing liquid, and combinations of two or more of these inks can be used. Furthermore, the combination of inks is not particularly limited; for example, it can be a water-based ink in which color materials such as dyes or pigments are dissolved in an aqueous solvent, a solvent-based ink in which color materials are dissolved in an organic solvent, or an ultraviolet-curing ink.

[0034] In this embodiment, a structure using four different types of ink is illustrated. These four types of ink are, for example, blue-green ink, magenta ink, yellow ink, and black ink, inks of different colors.

[0035] The control unit 20 controls the operation of various elements of the liquid injection device 100. For example, the control unit 20 includes processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and storage circuits such as semiconductor memory. The control unit 20 outputs a drive signal D and a control signal S to the liquid injection head 50. The drive signal D is a signal that includes drive pulses driving the drive element of the liquid injection head 50. The control signal S is a signal specifying whether to supply the drive signal D to the drive element. Furthermore, the control unit 20 is an example of a "control unit" that controls the drive of the heater 56, which will be described later.

[0036] The conveying mechanism 30, based on control implemented by the control unit 20, conveys the medium M in the Y1 direction, i.e., the conveying direction DM. The moving mechanism 40, based on control implemented by the control unit 20, causes the liquid injection head 50 to reciprocate in the X1 and X2 directions. Figure 1 In the example shown, the moving mechanism 40 has a generally box-shaped support 41, called a carriage, which houses the liquid injection head 50, and a conveyor belt 42 to which the support 41 is fixed. The support 41 supports the liquid injection head 50 and is made of metal. In addition to mounting the liquid injection head 50, the liquid reservoir 10 described above can also be mounted on the support 41.

[0037] The liquid ejector head 50 has a plurality of nozzles 54, and based on control implemented by the control unit 20, ink supplied from the liquid reservoir 10 is ejected from each of the plurality of nozzles of each nozzle along the Z2 direction toward the medium M. This ejection is performed in parallel by the transport of the medium M implemented by the transport mechanism 30 and the reciprocating movement of the liquid ejector head 50 implemented by the moving mechanism 40, thereby forming a predetermined image composed of ink on the surface of the medium M.

[0038] Alternatively, the liquid reservoir 10 can be connected to the liquid jet head 50 via a circulation mechanism. This circulation mechanism supplies ink to the liquid jet head 50 and recovers ink discharged from the liquid jet head 50 for resupply. By operating this circulation mechanism, the increase in ink viscosity can be suppressed, or the retention of air bubbles within the ink can be reduced.

[0039] 1-2. Installation status of the liquid injection head

[0040] Figure 2 This is a perspective view of the liquid injection head 50 and the support body 41 according to the first embodiment. Figure 2 As shown, the liquid injection head 50 is supported on the support body 41. The support body 41 is a component that supports the liquid injection head 50, and as described above, in this embodiment it is a generally box-shaped carriage. Although the structural material of the support body 41 is not particularly limited, it is preferably made of metal materials such as stainless steel, aluminum, titanium, or magnesium alloy. When the support body 41 is made of a metal material, the rigidity of the support body 41 is easily increased, and the liquid injection head 50 can be stably supported relative to the support body 41. Furthermore, in this case, since the support body 41 is conductive, a reference potential can be supplied to the liquid injection head 50 through the support body 41.

[0041] Here, an opening 41a and a plurality of screw holes 41b are provided on the support body 41. In this embodiment, the support body 41 is generally box-shaped with a plate-like bottom, for example, an opening 41a and a plurality of screw holes 41b are provided on the bottom. The liquid injection head 50 is fixed to the support body 41 by means of the threads of the plurality of screw holes 41b when it is inserted into the opening 41a. As described above, the liquid injection head 50 is mounted on the support body 41.

[0042] exist Figure 2 In the example shown, the number of liquid injection heads 50 mounted on the support 41 is one. Alternatively, the number of liquid injection heads 50 mounted on the support 41 may be two or more. In this case, the support 41 may, for example, be appropriately provided with a number or shape of openings 41a corresponding to the number of injection heads 50.

[0043] 1-3. Structure of the liquid injection head

[0044] Figure 3 This is an exploded perspective view of the liquid injection head 50 according to the first embodiment. Figure 4 for Figure 2 Sectional view along line AA in the diagram. Figure 5 for Figure 2 The BB line section view. Additionally, for ease of explanation, in... Figures 3 to 5 The various parts of the liquid injection head 50 are shown in a simplified manner. For example, although a gap is provided between the outer wall portion 5b and the flow channel structure 51 (described later), Figure 4 as well as Figure 5 For ease of drawing, the illustration of this gap has been omitted. Furthermore, in... Figure 4 as well as Figure 5 The illustrations of the heater 56 and heat transfer component 57, which will be described later, are simplified.

[0045] like Figure 3 As shown, the liquid injection head 50 has a flow channel structure 51, a substrate unit 52, a bracket 53, four head chips 54_1 to 54_4, a fixing plate 55, a heater 56, a heat transfer component 57, a cover 58, four pressing components 59_1 to 59_4 and two heat dissipation components 60_1 and 60_2.

[0046] The cover 58, substrate unit 52, flow channel structure 51, heat transfer component 57, heater 56, bracket 53, four head chips 54_1 to 54_4, and fixing plate 55 are arranged in this order facing the Z2 direction. Here, four pressing components 59_1 to 59_4 and two heat dissipation components 60_1 and 60_2 are arranged on the Z1-facing surface of the bracket 53. The various parts of the liquid injection head 50 will be described in turn below.

[0047] The flow channel structure 51 is a structure in which flow channels are provided inside for supplying ink stored in the liquid reservoir 10 to the four head chips 54. The flow channel structure 51 has flow channel components 51a and eight connecting pipes 51b.

[0048] Although not shown in the diagram, the flow channel component 51a is provided with four supply channels and four discharge channels for each of the four inks. Each of the four supply channels has an inlet for receiving ink and two outlets for discharging ink. Each of the four discharge channels has two inlets for receiving ink and one outlet for discharging ink. The inlets of each supply channel and the outlets of each discharge channel are respectively located on the surface of the flow channel component 51a facing the Z1 direction. Conversely, the outlets of each supply channel and the inlets of each discharge channel are respectively located on the surface of the flow channel component 51a facing the Z2 direction.

[0049] Furthermore, a plurality of wiring holes 51c are provided on the flow channel component 51a. These wiring holes 51c are holes through which the wiring substrate 54i of the feed head chip 54 (described later) passes toward the substrate unit 52. In addition, notches are provided at two locations in the circumferential direction on the side surface of the flow channel component 51a. Within the space formed by these notches, for example, wiring components (not shown) that connect the heater 56 and the substrate unit 52 are arranged. Furthermore, the flow channel component 51a is provided with holes (not shown) and is fixed to the bracket 53 by means of threaded fastening through these holes.

[0050] Although not illustrated, the flow channel component 51a is constructed from a laminate made by laminating multiple substrates in the direction along the Z-axis. Grooves and holes for the aforementioned supply and discharge channels are appropriately provided on each of the multiple substrates. The multiple substrates are joined together, for example, by adhesives, brazing, welding, or threaded fastening. Furthermore, a sheet-like sealing member made of rubber or the like may be appropriately disposed between the multiple substrates as needed. Moreover, the number and thickness of the substrates constituting the flow channel component 51a are determined by the shape of the supply and discharge channels and are not particularly limited; they can be any number or thickness.

[0051] As the structural materials for each of the multiple substrates, materials with good thermal conductivity are preferably used. For example, metallic materials such as stainless steel, titanium, and magnesium alloys with a thermal conductivity of 10.0 W / m·K or higher at room temperature (20°C) are preferred, as well as ceramic materials such as silicon carbide, aluminum nitride, sapphire, alumina, silicon nitride, cermet, and yttrium oxide. By using such metallic or ceramic materials to construct the flow channel component 51a, the ink within the flow channel component 51a can be effectively heated using heat from the heater 56.

[0052] The eight connecting pipes 51b are pipe bodies protruding from the Z1-oriented surface of the flow channel component 51a. The eight connecting pipes 51b correspond to the four supply flow channels and four discharge flow channels mentioned above, and are connected to the inlet of the corresponding supply flow channel or the outlet of the corresponding discharge flow channel. While the structural material of each connecting pipe 51b is not particularly limited, it is preferable to use, for example, metallic materials such as stainless steel, titanium, and magnesium alloys, or ceramic materials such as silicon carbide, aluminum nitride, sapphire, alumina, silicon nitride, cermet, and yttrium oxide.

[0053] The liquid reservoir 10 is connected to four of the eight connecting pipes 51b corresponding to the four supply channels, to receive supplies of different types of ink. On the other hand, the four connecting pipes 51b corresponding to the four discharge channels are connected to a discharge container or auxiliary tank, which discharges ink at a predetermined time, such as during the initial filling of the liquid jet head 50. The auxiliary tank is positioned between the liquid reservoir 10 and the liquid jet head 50 and is used to retain the liquid. During printing or other normal operations, the four connecting pipes 51b corresponding to the four discharge channels are sealed with a cap or similar sealing material. Furthermore, when the liquid reservoir 10 is connected to the liquid jet head 50 via a circulation mechanism, the four connecting pipes 51b corresponding to the four discharge channels are normally connected to the ink recovery channel of that circulation mechanism.

[0054] The base unit 52 is an assembly having mounting components for electrically connecting the liquid injection head 50 to the control unit 20. The base unit 52 includes a circuit board 52a, a connector 52b, and a support plate 52c.

[0055] The circuit board 52a is a rigid wiring board or other printed wiring board with wiring for electrically connecting each chip 54 and connector 52b. The circuit board 52a is disposed on the flow channel structure 51 with the support plate 52c in between, and the connector 52b is provided on the surface of the circuit board 52a facing the Z1 direction.

[0056] Connector 52b is a connecting component for electrically connecting the liquid injection head 50 and the control unit 20. Support plate 52c is a plate-shaped component for mounting the circuit board 52a onto the flow channel structure 51. The circuit board 52a is mounted on one side of the support plate 52c and is fixed to the support plate 52c by threaded fastening or the like. Furthermore, the other side of the support plate 52c contacts the flow channel structure 51, and in this state, the support plate 52c is fixed to the flow channel structure 51 by threaded fastening.

[0057] Here, the support plate 52c not only functions to support the circuit board 52a as described above, but also ensures electrical insulation between the circuit board 52a and the flow channel structure 51, or provides thermal insulation between the heater 56 and the circuit board 52a. From the viewpoint of appropriately fulfilling these functions, the structural material of the support plate 52c is preferably a material with excellent insulation and thermal insulation properties. Specifically, it is preferably a resin material such as Zylon-modified polyphenylene ether resin, polyphenylene sulfide (PPS) resin, or polypropylene resin. Zylon is a registered trademark. Furthermore, in addition to resin materials, the structural material of the support plate 52c may also include fiber substrates such as glass fiber or fillers such as alumina particles.

[0058] The support 53 is a structure that houses and supports the four head chips 54. The structural material of the support 53 is preferably a material with good thermal conductivity, such as stainless steel, titanium, or magnesium alloys with a thermal conductivity of 10.0 W / m·K or higher at room temperature (20°C), or ceramic materials such as silicon carbide, aluminum nitride, sapphire, alumina, silicon nitride, cermet, and yttrium oxide. By using such metal or ceramic materials to construct the support 53, heat from the heater 56 can be effectively transferred to each head chip 54 via the support 53.

[0059] The support 53 is generally tray-shaped. Furthermore, when viewed from above, the support 53 appears rectangular or approximately rectangular. Here, "approximately rectangular" includes both shapes that can be substantially called rectangular and shapes resembling rectangles. A shape that can be substantially called rectangular is, for example, a shape obtained by chamfering the four corners of a rectangle using C-bevels or R-bevels. A shape resembling a rectangle is, for example, an octagonal shape that includes the four sides of a rectangle and four sides shorter than those four sides.

[0060] The support 53 has a recess 53a, a plurality of ink holes 53b, a plurality of wiring holes 53c, a plurality of recesses 53d, a plurality of screw holes 53i, and a plurality of screw holes 53k. The recess 53a is a space of a laminate that opens in the Z1 direction and houses the aforementioned flow channel component 51a, heater 56, and heat transfer component 57. The plurality of ink holes 53b are flow channels that allow ink to flow between the head chip 54 and the flow channel structure 51. The plurality of wiring holes 53c are holes through which the wiring substrate 54i of the head chip 54 passes toward the substrate unit 52. The plurality of recesses 53d are spaces that open in the Z2 direction and house the head chip 54. The plurality of screw holes 53i are screw holes for threading the support 53 onto the support body 41. The plurality of screw holes 53k are screw holes for threading the cover 58 onto the support 53. Further details regarding the support 53 will be provided below. Figures 7 to 9 Let me explain.

[0061] Head chips 54_1 to 54_4 are respectively Figure 1 The head chip 54 is shown. In the following text, without distinguishing between head chips 54_1 to 54_4, these chips are referred to as head chip 54. Furthermore, in the following text, the symbols of the structural elements corresponding to head chips 54_1 to 54_4 are appropriately marked with sub-numbers “_1” to “_4”.

[0062] Each die 54 ejects ink. More specifically, each die 54 has a nozzle face FN. Figure 3 The illustration is omitted, but multiple nozzles for spraying a first ink and multiple nozzles for spraying a second ink of a different type than the first ink are provided on the nozzle surface FN. Here, the first ink and the second ink are two of the four types of inks mentioned above. For example, in each of head chips 54_1 and 54_2, two of the four inks are used as the first ink and the second ink. Furthermore, in each of head chips 54_3 and 54_4, the remaining two of the four inks are used. A wiring board 54i is provided on each head chip 54. Additionally, in… Figure 3 The simplified diagram below illustrates the structure of each head chip 54. The structure of the head chip 54 will be discussed in detail below. Figure 6 Let me describe it in detail.

[0063] The fixing plate 55 is a plate-shaped component that has four head chips 54 and a bracket 53 fixed thereon. Specifically, the fixing plate 55 is configured such that the four head chips 54 are sandwiched between it and the bracket 53, and each head chip 54 and the bracket 53 are fixed by adhesive or the like.

[0064] Multiple openings 55a are provided on the fixing plate 55 to expose the nozzle surfaces FN of the four head chips 54. Figure 3 In the example shown, the plurality of openings 55a are individually provided for each head chip 54. The fixing plate 55 is made of metal materials such as stainless steel, titanium, and magnesium alloy, and has the function of transferring heat from the support 53 to each head chip 54. In addition, the fixing plate 55 is conductive. Therefore, the fixing plate 55 is grounded via the support 53 and the support body 41, and also functions as an electrostatic shield to prevent the effects of static electricity from the dielectric M. Alternatively, the fixing plate 55 may also be constructed by laminating multiple plate-shaped parts made of metal materials.

[0065] Alternatively, the opening 55a can be shared by two or more head chips 54. However, when the opening 55a is provided separately for each head chip 54, the contact area between the fixing plate 55 and each head chip 54 is easily increased, thus effectively transferring heat from the support 53 to each head chip 54.

[0066] Heater 56 is a planar heater disposed between the flow channel structure 51 and the support 53. Heater 56 is, for example, a thin-film heater having a thin-film substrate, an insulating film, and a heating resistor sandwiched between the substrate and the film. The substrate is made of an insulating material, such as a resin material like polyimide or PET (polyethylene terephthalate). The film is, for example, made of a resin material like polyimide or PET (polyethylene terephthalate). The heating resistor is an electric heating wire patterned on the substrate, made of a metal material such as stainless steel, copper, or a nickel alloy. Alternatively, heater 56 can also be a planar heater such as a silicone rubber heater or a ceramic heater with a heating resistor sandwiched between silicone rubber incorporating glass fibers. Furthermore, the heating resistor is heating resistor 56c or 56d, described later.

[0067] A plurality of holes 56a and a plurality of holes 56b are provided on the heater 56. The plurality of holes 56a are respectively holes through which the wiring substrate 54i of the head chip 54 passes and the flow channel 53l formed on the support 53 passes. The ink holes 53b formed inside the flow channel 53l are part of the flow channel through which ink flows between the head chip 54 and the flow channel structure 51. The flow channel 53l protrudes, for example, from the upper surface of the support 53 in the Z1 direction (the first surface F1 described later) in the Z1 direction. Moreover, by bonding the top end of the flow channel 53l on the Z1 direction side to the lower surface of the flow channel structure 51 in the Z2 direction, the ink holes 53b and the flow channel inside the flow channel structure 51 are sealed in a liquid-tight state. The plurality of holes 56b are also holes for threading the heater 56 onto the support 53.

[0068] In particular, heater 56, when viewed from above, is divided into multiple regions with varying heat output per unit time to uniformly heat head chips 54_1 to 54_4. Furthermore, the structure of heater 56 will be discussed below based on... Figures 9 to 12 Let me describe it in detail.

[0069] The heat transfer component 57 is a plate-shaped component with thermal conductivity, disposed between the flow channel structure 51 and the heater 56. The heat transfer component 57 functions to transfer heat in both the thickness direction and the surface direction. Through this function, heat from the heater 56 is effectively transferred to the flow channel structure 51 via the heat transfer component 57. Here, the surface-direction heat transfer of the heat transfer component 57 reduces uneven heating of the flow channel structure 51 caused by localized uneven heating of the heater 56.

[0070] From the viewpoint of appropriately fulfilling the aforementioned functions, the heat transfer component 57 is constructed from a thermally conductive material such as a metal or ceramic. Examples of such metal materials include stainless steel, aluminum, titanium, and magnesium alloys. Examples of such ceramic materials include silicon carbide, aluminum nitride, sapphire, alumina, silicon nitride, cermets, and yttrium oxide. Preferably, the heat transfer component 57 is made of a material with higher thermal conductivity compared to the structural material of the flow channel structure 51 or the support 53.

[0071] The heat transfer component 57 is provided with a plurality of holes 57a, a plurality of wiring holes 57b, and a plurality of holes 57c. The plurality of holes 57a are for inserting the aforementioned flow channel tube 53l. The plurality of wiring holes 57b are for the wiring substrate 54i of the head chip 54 to pass through towards the substrate unit 52. The plurality of holes 57c are for threading the heat transfer component 57 onto the bracket 53. In this embodiment, two of the plurality of holes 57c are used to simultaneously fasten the heater 56 and the heat transfer component 57 onto the bracket 53. Furthermore, the heat transfer component 57 can be provided only as needed and may be omitted.

[0072] The cover 58 is a box-shaped component that houses the substrate unit 52. The cover 58 is made of resin materials such as modified polyphenylene ether resin, polyphenylene sulfide resin, and polypropylene resin, for example, similar to the support plate 52c described above.

[0073] The cover 58 has eight through holes 58a and openings 58b. The eight through holes 58a correspond to the eight connecting pipes 51b of the flow channel structure 51, and a corresponding connecting pipe 51b is inserted into each through hole 58a. In the openings 58b, the connectors 52b mentioned above pass through from the inside to the outside of the cover 58.

[0074] Heat dissipation components 60_1 and 60_2 are thermally conductive components used to release heat from the drive circuit 54j to the bracket 5. Furthermore, in the following text, without distinguishing between the two heat dissipation components 60_1 and 60_2, these components are referred to as heat dissipation component 60.

[0075] The heat dissipation component 60 provides a thermal connection to the drive circuit 54j and the flow channel structure 51 or the bracket 53. Furthermore, in this specification, "thermal connection" refers to a situation where any one of the following conditions a, b, or c is met: Condition a: The two components are physically directly connected. Condition b: The two components are arranged with a gap of 100 μm or less. Condition c: The two components are physically connected via another component with a thermal conductivity of 1.0 W / m·K or higher at room temperature (20°C). Additionally, heat transfer oil or adhesives may be present between the two components under each condition. In this case, from the viewpoint of improving thermal conductivity, the adhesive is preferably a filler containing thermally conductive materials.

[0076] The heat dissipation component 60 is made of a metal material or a thermally conductive material such as silicon carbide, aluminum nitride, sapphire, alumina, silicon nitride, cermet, or yttrium oxide. Examples of such metal materials include gold, silver, copper, stainless steel, aluminum, titanium, and magnesium alloys. The heat dissipation component 60 is preferably made of a material with higher thermal conductivity compared to the flow channel structure 51 or the support 53. By using such a heat dissipation component 60 with high thermal conductivity, the drive circuit 54j can be effectively cooled.

[0077] exist Figure 3 In the example shown, the heat dissipation component 60 is a U-shaped plate with portions 60a, 60b, and 60c. Portion 60a is disposed between the flow channel structure 51 and the support 53 and is fixed to either the support 53 or the flow channel structure 51. Portion 60b extends along the Z1 direction from its X2 end and is connected to the drive circuit 54j. Portion 60c extends along the Z1 direction from its X1 end and is connected to a drive circuit 54j different from that of portion 60b. In this embodiment, the heat dissipation component 60 is fixed to the support 53 by threaded fastening.

[0078] Pressing members 59_1 to 59_4 are elastic members configured such that the drive circuit 54j (described later) and the wiring board 54i (described later) are sandwiched between the heat dissipation member 60, and press the drive circuit 54j and the wiring board 54i toward the heat dissipation member 60. Furthermore, in the following text, without distinguishing between the four pressing members 59_1 to 59_4, these members will be referred to as pressing member 59.

[0079] The pressing member 59 is preferably made of a material with excellent thermal insulation properties, so that the heat from the drive circuit 54j can be transferred to the heat dissipation member 60 more easily than the heat from the pressing member 59.

[0080] When the pressing member 59 is made of a material with excellent thermal insulation properties, an elastic material is preferred, specifically a material with a thermal conductivity of less than 1.0 W / m·K at room temperature (20°C). Examples of such materials include modified polyphenylene ether resin, polyphenylene sulfide resin, and polypropylene resin. By forming the pressing member 59 from a resin material, the pressing member 59 can be manufactured at a low cost. The pressing member 59, which uses a resin material as a structural material, is obtained, for example, by injection molding. Furthermore, from the viewpoint of improving the mechanical strength of the pressing member 59, inorganic fillers such as alumina can be included in the structural material of the pressing member 59. In addition, from the viewpoint of appropriately maintaining the pressing state to the drive circuit 54j, etc., achieved by the pressing member 59, it is preferable that the softening point of the resin material constituting the pressing member 59 is higher than the upper limit temperature of the heater 56.

[0081] The pressing member 59 is positioned in a state where it has undergone slight elastic deformation in the direction away from the heat dissipation member 60. Through the elastic force generated by this elastic deformation, the pressing member 59 presses the drive circuit 54j toward the heat dissipation member 60. Figure 3 In the example shown, the pressing member 59 is a plate-shaped member bent into an L-shape, and has a base portion 59a and a bent portion 59b. The base portion 59a is disposed between the flow channel structure 51 and the bracket 53, and is fixed to the bracket 53 or the flow channel structure 51. The bent portion 59b extends from the base portion 59a along the Z1 direction and presses against the drive circuit 54j. In this embodiment, the pressing member 59 is fixed to the bracket 53 by a screw fastener.

[0082] 1-4. Structure of the head chip

[0083] Figure 6 This is a cross-sectional view showing an example of head chip 54. (See attached image.) Figure 6 As shown, the head chip 54 has a plurality of nozzles N arranged along the Y-axis. The plurality of nozzles N are divided into a first column L1 and a second column L2 arranged side by side with intervals between them along the X-axis. The first column L1 and the second column L2 are sets of a plurality of nozzles N arranged in a straight line along the Y-axis.

[0084] The head chip 54 has a structure that is approximately symmetrical to each other along the X-axis. However, the positions of the plurality of nozzles N in the first column L1 and the plurality of nozzles N in the second column L2 along the Y-axis can be either identical or different. Figure 6 The diagram illustrates a structure in which multiple nozzles N in the first column L1 and multiple nozzles N in the second column L2 are positioned in the same direction along the Y-axis.

[0085] like Figure 6As shown, the head chip 54 has a flow channel substrate 54a, a pressure chamber substrate 54b, a nozzle plate 54c, a vibration absorber 54d, a vibration plate 54e, multiple piezoelectric elements 54f, a protection plate 54g, a housing 54h, a wiring substrate 54i, and a drive circuit 54j.

[0086] The flow channel substrate 54a and the pressure chamber substrate 54b are laminated in this order in the Z1 direction to form a flow channel for supplying ink to a plurality of nozzles N. In the region located in the Z1 direction relative to the laminate formed by the flow channel substrate 54a and the pressure chamber substrate 54b, a vibrating plate 54e, a plurality of piezoelectric elements 54f, a protective plate 54g, a housing 54h, a wiring substrate 54i, and a drive circuit 54j are provided. On the other hand, in the region located in the Z2 direction relative to the laminate, a nozzle plate 54c and a vibration absorber 54d are provided. Each element of the head chip 54 is a plate-shaped component that is generally elongated in the Y direction and is bonded to each other, for example, by an adhesive. Hereinafter, each element of the head chip 54 will be described in turn.

[0087] The nozzle plate 54c is a plate-shaped component having a plurality of nozzles N, each in a first row L1 and a second row L2. Each nozzle N is a through-hole through which ink passes. Here, the surface of the nozzle plate 54c facing the Z2 direction is the nozzle surface FN. The nozzle plate 54c is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing techniques such as dry etching or wet etching. However, other known methods and materials may be appropriately used in the manufacture of the nozzle plate 54c. Furthermore, although the cross-sectional shape of the nozzles is typically circular, it is not limited to this; for example, it may be a non-circular shape such as a polygon or an ellipse.

[0088] On the flow channel substrate 54a, a space R1, a plurality of supply channels Ra, and a plurality of connecting channels Na are respectively provided for the first column L1 and the second column L2. The space R1 is an elongated opening extending along the Y-axis when viewed from above along the Z-axis. The supply channels Ra and the connecting channels Na are through holes formed for each nozzle N. Each supply channel Ra is connected to the space R1.

[0089] The pressure chamber substrate 54b is a plate-shaped component having a plurality of pressure chambers C, referred to as chambers, respectively provided for the first column L1 and the second column L2. The plurality of pressure chambers C are arranged along the Y-axis. Each pressure chamber C is formed for each nozzle N and is an elongated space extending along the X-axis when viewed from above. Similar to the nozzle plate 54c described above, the flow channel substrate 54a and the pressure chamber substrate 54b are manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology. However, other known methods and materials may be appropriately used in the respective manufacturing of the flow channel substrate 54a and the pressure chamber substrate 54b. The flow channel substrate 54a is preferably made of a material with a thermal conductivity of 10.0 W / m·K or higher; in addition to a single-crystal silicon substrate, it may also be formed of stainless steel.

[0090] The pressure chamber C is the space located between the flow channel substrate 54a and the vibrating plate 54e. For the first column L1 and the second column L2, multiple pressure chambers C are arranged in the direction along the Y-axis. Furthermore, the pressure chamber C is connected to the connecting flow channel Na and the supply flow channel Ra, respectively. Therefore, the pressure chamber C is connected to the nozzle N via the connecting flow channel Na and to the space R1 via the supply flow channel Ra.

[0091] A vibrating plate 54e is disposed on the Z1-oriented surface of the pressure chamber substrate 54b. The vibrating plate 54e is a plate-shaped component capable of elastic vibration. The vibrating plate 54e has, for example, a first layer and a second layer, and these layers are laminated in this order in the Z1 direction. The first layer is, for example, an elastic film made of silicon oxide (SiO2). This elastic film is formed, for example, by thermal oxidation of one side of a single-crystal silicon substrate. The second layer is, for example, an insulating film made of zirconium oxide (ZrO2). This insulating film is formed, for example, by sputtering a zirconium layer and then by thermal oxidation of that layer. Furthermore, the vibrating plate 54e is not limited to a structure formed by laminating the first and second layers described above; for example, it can be composed of a single layer or three or more layers.

[0092] On the Z1-oriented surface of the vibrating plate 54e, for the first column L1 and the second column L2, multiple piezoelectric elements 54f are arranged as driving elements, corresponding to the nozzles N. Each piezoelectric element 54f is a driven element that deforms upon the supply of a driving signal. When viewed from above, each piezoelectric element 54f appears as an elongated strip extending along the X-axis. The multiple piezoelectric elements 54f are arranged along the Y-axis in a manner corresponding to multiple pressure chambers C. When viewed from above, the piezoelectric elements 54f overlap with the pressure chambers C.

[0093] Although not illustrated, each piezoelectric element 54f has a first electrode, a piezoelectric layer, and a second electrode, and these components are laminated in this order along the Z1 direction. One of the first and second electrodes is a separate electrode arranged independently for each piezoelectric element 54f, and a driving signal is applied to this electrode. The other of the first and second electrodes is a strip-shaped common electrode extending continuously along the Y-axis across multiple piezoelectric elements 54f, and a predetermined reference potential is supplied to this other electrode. Examples of metallic materials used as electrodes include platinum (Pt), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu). These materials can be used individually or in combination by alloying or lamination. The piezoelectric layer is made of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3) and, for example, is a strip extending continuously along the Y-axis across multiple piezoelectric elements 54f. However, the piezoelectric layer may also be a single unit spanning multiple piezoelectric elements 54f. In this case, a through-hole extending along the X-axis is provided in the piezoelectric layer in the region corresponding to the gap between adjacent pressure chambers C when viewed from above. When the vibrating plate 54e vibrates in a manner linked to the deformation of the piezoelectric elements 54f, the pressure in the pressure chamber C changes, causing ink to be ejected from the nozzle N. Alternatively, a heating element that heats the ink in the pressure chamber C may be used as the driving element instead of the piezoelectric element 54f.

[0094] The protective plate 54g is a plate-shaped component disposed on the Z1-oriented surface of the vibrating plate 54e, and it protects the multiple piezoelectric elements 54f while strengthening the mechanical strength of the vibrating plate 54e. Here, multiple piezoelectric elements 54f are housed between the protective plate 54g and the vibrating plate 54e. The protective plate 54g is, for example, made of resin material.

[0095] The housing 54h is a housing for storing ink supplied to multiple pressure chambers C. The housing 54h is made of, for example, resin material. Spaces R2 are provided in the housing 54h for the first column L1 and the second column L2, respectively. Spaces R2 communicate with the aforementioned space R1 and, together with space R1, function as reservoirs R for storing the ink supplied to the multiple pressure chambers C. An inlet IO for supplying ink to each reservoir R is provided on the housing 54h. The ink in each reservoir R is supplied to the pressure chamber C via a supply channel Ra.

[0096] The absorber 54d, also known as a flexible substrate, is a flexible resin film that forms the wall of the reservoir R and absorbs pressure fluctuations of the ink within the reservoir R. Alternatively, the absorber 54d can be a flexible sheet of metal. The Z1-facing surface of the absorber 54d is bonded to the flow channel substrate 54a using an adhesive or similar material. On the other hand, a frame 54k is bonded to the Z2-facing surface of the absorber 54d using an adhesive or similar material. The frame 54k is a frame-shaped component along the outer periphery of the absorber 54d and contacts the aforementioned fixing plate 55. Here, the frame 54k is constructed from metal materials such as stainless steel, aluminum, titanium, and magnesium alloy. By constructing the frame 54k from a metal material, heat from the heater 56 can be appropriately transferred to the ink within the head chip 54 via the support 53 and the fixing plate 55.

[0097] exist Figure 6 The heat transfer path H1 from heater 56 to head chip 54 is schematically shown using dashed arrows. Although a portion of the transfer path H1 includes a resin absorber 54d, a material with low thermal conductivity, the absorber 54d is thin and has very low thermal resistance because it is formed as a thin film for flexibility. Therefore, the effect of the absorber 54d in hindering heat conduction from frame 54k to flow channel substrate 54a is minimal.

[0098] The wiring board 54i is a mounting component installed on the Z1-oriented surface of the vibrating plate 54e for electrically connecting the control unit 20 and the head chip 54. The wiring board 54i is, for example, a flexible wiring board such as COF (Chip On Film), FPC (Flexible Printed Circuit), or FFC (Flexible Flat Cable). In this embodiment, a drive circuit 54j is mounted on the wiring board 54i for supplying drive voltage to each piezoelectric element 54f. The drive circuit 54j is a circuit including a switching element that switches whether to supply at least a portion of the waveform contained in the drive signal D as a drive pulse to the drive element based on a control signal S.

[0099] 1-5. Structure of the support

[0100] Figure 7 A bottom view of the bracket 53 in the first embodiment, viewed in the Z1 direction. Figure 8 This is a top view of the bracket 53 in the first embodiment, viewed in the Z2 direction. (See attached image.) Figure 7 as well as Figure 8As shown, the support 53, which is generally tray-shaped as described above, has a bottom 5a, an outer wall portion 5b, and a flange portion 5c.

[0101] The bottom 5a is generally plate-shaped, extending in a direction orthogonal to the Z-axis, and forms the bottom surface of the aforementioned recess 53a. Here, the bottom 5a is divided into a holding portion 5a1 and a connecting portion 5a2, the connecting portion 5a2 being arranged to surround the outer periphery of the holding portion 5a1 and being thinner than the holding portion 5a1.

[0102] The holding part 5a1 has the four recesses 53d described above, and holds the four head chips 54. Here, each head chip 54 is housed in the space surrounded by the inner wall surface of each recess 53d and the fixing plate 55 described above.

[0103] like Figure 7 As shown by the double-dotted lines, head chips 54_1, 54_2, 54_3, and 54_4 are arranged in an alternating manner when viewed from above. Specifically, head chips 54_1, 54_2, 54_3, and 54_4 are arranged in this order in the X1 direction. However, head chips 54_1 and 54_3 are positioned offset from head chips 54_2 and 54_4 in the Y1 direction. Here, head chips 54_1 and 54_3 are arranged in a manner that aligns their positions with each other along the Y-axis in the X-axis direction. Similarly, head chips 54_2 and 54_4 are arranged in a manner that aligns their positions with each other along the Y-axis in the X-axis direction. Furthermore, as... Figure 8 As shown by the double-dotted line, the heater 56 is configured to include a holding part 5a1 when viewed along the Z-axis.

[0104] In addition, such as Figure 7 As shown, in addition to the four recesses 53d, the retaining part 5a1 also has two recesses 53h. Each recess 53h is a recess for removing the interior and is arranged between the four recesses 53d, having the same depth as the recesses 53d. Such a retaining part 5a1 has a heat-receiving part 5a11 and a sidewall part 5a12.

[0105] The heated portion 5a11 is plate-shaped, having a first surface F1 and a second surface F2 extending in a direction orthogonal to the Z-axis, and forming the bottom surfaces of recesses 53d and 53h. The first surface F1 faces the Z1 direction and is the heated surface that receives heat from the heater 56. A flow channel structure 51 is mounted on the first surface F1 via the aforementioned heater 56 and heat transfer member 57. Four pressing members 59 and two heat dissipation members 60 are provided on the first surface F1. Furthermore, the second surface F2 faces the Z2 direction and forms the bottom surface of recesses 53d and 53h.

[0106] exist Figure 7 as well as Figure 8 In the example shown, multiple ink holes 53b and multiple wiring holes 53c are provided on the heated portion 5a11 with openings on the first surface F1 and the second surface F2, respectively. In addition to these structures, the first surface F1 of the heated portion 5a11 also has multiple holes 53e, multiple holes 53f, multiple screw holes 53g, multiple recesses 53m, multiple screw holes 53n, multiple recesses 53o, and multiple screw holes 53p.

[0107] Multiple holes 53e are for positioning the head chip 54 relative to the support 53, and protrusions (not shown) provided on the head chip 54 are inserted therein. Multiple holes 53f are for inserting positioning pins used in positioning the flow channel structure 51, the heater 56, and the heat transfer component 57. Multiple screw holes 53g are screw holes for threaded fastening of the heat transfer component 57. Multiple screw holes 53g are screw holes for threaded fastening of the flow channel structure 51.

[0108] Multiple recesses 53m are recesses for mounting the pressing member 59. A base portion 59a of the pressing member 59 is disposed within each recess 53m. Figure 8 In the example shown, the recess 53m is located between the wiring hole 53c and the outer wall portion 5b when viewed from the Z2 direction. The shape of the recess 53m as seen from above corresponds to the shape of the base portion 59a. Therefore, positioning of the pressing member 59 relative to the bracket 53 can be performed. A screw hole 53n is provided on the bottom surface of the recess 53m. The multiple screw holes 53n are internal threads for threaded fastening of the pressing member 59 relative to the bracket 53.

[0109] The plurality of recesses 53o are recesses for housing the heat dissipation component 60. A portion 60a of the heat dissipation component 60 is disposed within each of the recesses 53o. Figure 8In the example shown, the recess 53o is located between two wiring holes 53c arranged side-by-side in the X1 or X2 direction when viewed from the Z2 direction. The shape of the recess 53o as seen from above corresponds to the shape of part 60a. Therefore, positioning of the heat dissipation component 60 relative to the bracket 53 is possible. A screw hole 53p is provided on the bottom surface of the recess 53o. The plurality of screw holes 53p are internal threads for threaded fastening of the heat dissipation component 60 relative to the bracket 53. In addition, the recess 53o is an example of a "connection part that is thermally connected to the drive circuit" and is thermally connected to the drive circuit 54j via the heat dissipation component 60.

[0110] The sidewall portion 5a12 protrudes from the heated portion 5a11 in the Z2 direction and forms the side surfaces of the recesses 53d and 53h. A connecting portion 5a2 is connected to the end of the sidewall portion 5a12 in the Z2 direction. Here, when viewed from the direction along the Z-axis, the shape of the sidewall portion 5a12 is the shape after removing the shapes of the multiple recesses 53d and multiple recesses 53h from the shape of the heated portion 5a11.

[0111] The connecting portion 5a2 is configured to surround the retaining portion 5a1 when viewed along the Z-axis. The connecting portion 5a2 is plate-shaped, extending from the side wall portion 5a12 in a direction orthogonal to the Z-axis, and spans the entire circumference to connect the side wall portion 5a12 and the outer wall portion 5b. In addition, the connecting portion 5a2 can be in the shape of having a missing part, or it can be composed of multiple portions spaced apart and arranged side by side in the circumferential direction.

[0112] The outer wall portion 5b is a frame-shaped portion that extends in the Z1 direction from the periphery of the bottom 5a to the entire circumference, and forms the side surface of the aforementioned recess 53a.

[0113] The flange portion 5c is plate-shaped, protruding outward from its end edge in the Z1 direction of the outer wall portion 5b and in a direction orthogonal to the Z-axis. Thus, the outer periphery of the connecting portion 5a2 of the bottom 5a is connected to the inner periphery of the flange portion 5c via the outer wall portion 5b. Figure 7 as well as Figure 8 In the example shown, the flange 5c is rectangular or approximately rectangular when viewed from above. Therefore, the bracket 53 has a rectangular or approximately rectangular shape when viewed from above. In addition to the aforementioned plurality of screw holes 53i and plurality of screw holes 53k, the flange 5c also has plurality of holes 53j. These holes 53j are for positioning the bracket 53 relative to the support body 41 by means of protrusions (not shown) inserted into the support body 41.

[0114] 1-6. Structure of the heater

[0115] Figure 9 This is a plan view of the heater 56 in the first embodiment. Figure 9 In the diagram, solid lines are used to represent the shape of the heater 56 as observed in the Z2 direction, and double-dotted lines are used to represent the respective shapes of the holding part 5a1 and the plurality of head chips 54 as observed in the Z2 direction.

[0116] like Figure 9 As shown, when viewed from above along the Z-axis, the outer edge OE1 of the retaining part 5a1 has a shape corresponding to the arrangement of the head chips 54_1, 54_2, 54_3, and 54_4. That is, when viewed from above, the outer edge OE1 has a shape such that a pair of opposite corners of the four corners of the rectangle and their surrounding portions form a roughly rectangular notch.

[0117] Similarly, when viewed from above along the Z-axis, the outer edge OE2 of the heater 56 has a shape corresponding to the arrangement of the head chips 54_1, 54_2, 54_3, and 54_4. In this embodiment, the outer edge OE2 is generally the same shape as the outer edge OE1 of the holding portion 5a1 described above. That is, the outer edge OE2 can also be described as being along the shape of the outer edge OE1.

[0118] Figure 10 This is a diagram illustrating the heat distribution of the heater 56 in the first embodiment. (See diagram below.) Figure 10 As shown, heater 56 includes an outer peripheral region RE1 and a central region RE2. Additionally, in Figure 10 In this design, for ease of understanding, the outer region RE1 and the central region RE2 are represented by different shades of gray. Furthermore, in... Figure 10 The diagram schematically shows a pattern of the heating resistors of heater 56.

[0119] The outer peripheral region RE1 is the area formed along the outer edge OE of the aforementioned support 53 when viewed from above. Figure 10 In the example shown, the outer peripheral region RE1 is a frame-like region surrounding the assembly of four holes 56a when viewed from above. Here, the outer peripheral region RE1 is shaped along the outer perimeter of the outer edge OE2 and is provided along the outer edge OE2 and spans the entire circumference. In addition, as mentioned above, since the outer edge OE2 is generally the same shape as the outer edge OE1, the outer peripheral region RE1 can also be described as being shaped along the outer perimeter of the outer edge OE1.

[0120] A heating resistor 56c is disposed in the outer peripheral region RE1. The heating resistor 56c is configured across the entire circumference of the outer peripheral region RE1. Figure 10In the example shown, the heating resistor 56c has a wave-like shape that extends along the circumferential direction of the outer peripheral region RE1 while meandering. Furthermore, the shape and arrangement of the heating resistor 56c are not limited to any particular type, as long as they can generate heat approximately uniformly within the outer peripheral region RE1. Figure 10 The example shown is not for any shape and configuration.

[0121] The heating resistor 56c heats up by receiving a power supply, based on the control implemented by the control unit 20 described above. In this embodiment, the control unit 20 controls the power supply to the heating resistor 56c to achieve a predetermined temperature based on the detection result of the temperature sensor 70 configured in the central region RE2. The temperature sensor 70 is, for example, a thermistor or a thermocouple. Furthermore, the configuration of the temperature sensor 70 is not limited to… Figure 10 The example shown is not for any configuration; for example, it can be set in the head chip 54 or on the bracket 53.

[0122] The central region RE2 is located on the inner side compared to the peripheral region RE1 when viewed from above. Figure 10 In the example shown, the central region RE2 is composed of two interconnected first central regions RE2a and RE2b. The first central region RE2a is located within the four holes 56a when viewed from above. Figure 10 The left side of the image shows a roughly quadrilateral region between two adjacent holes 56a along the X-axis. The first central region RE2b is located between the four holes 56a when viewed from above. Figure 10 The right side of the area is a roughly quadrilateral-shaped region between the other two holes 56a arranged side by side along the X-axis.

[0123] A heating resistor 56d is provided in the central region RE2. The heating resistor 56d is configured to span approximately the entire area of ​​the central region RE2. Figure 10 In the example shown, the heating resistor 56d has a wave-like shape that extends along the Y-axis while exhibiting a meandering motion. Furthermore, the shape and configuration of the heating resistor 56d are not limited to... Figure 10 The example shown is not for any shape and configuration.

[0124] In this embodiment, since the heating resistor 56d is not supplied with electricity and is therefore not energized, it does not generate heat. Therefore, the heat generated per unit area of ​​the central region RE2 is less than the heat generated per unit area of ​​the outer peripheral region RE1. As a result, the heat generated per unit time of the central region RE2 is less than the heat generated per unit time of the outer peripheral region RE1.

[0125] Here, the heating resistor 56d is not electrically connected to the heating resistor 56c described above. Furthermore, although the heating resistor 56d does not heat up when energized, it functions as a heat transfer element that transfers heat from the outer peripheral region RE1 towards the surface. Additionally, the heating resistor 56d also functions as a spacer that defines the distance between the support 53 and the heat transfer component 57. Since the shape of this heating resistor 56d does not need to consider heating caused by energization, it is sufficient to consider its function solely as a heat transfer element or spacer as described above.

[0126] 1-7. Heat transfer path from the heater

[0127] Figure 11 This is a diagram illustrating the heat transfer path H2 from the heater 56 in the first embodiment. Figure 12 This is a diagram illustrating the heat transfer path H3 from the heater 56 in the first embodiment. Additionally, for ease of explanation, in Figure 11 as well as Figure 12 The bracket 53, head chip 54, fixing plate 55 and heater 56 are schematically shown.

[0128] As described above, the support 53 appears rectangular or roughly rectangular when viewed from above, and as... Figure 11 As shown, in the short-side direction of the bracket 53, the bracket 53 does not contact the support body 41. Therefore, in the short-side direction of the bracket 53, a portion of the heat from the heater 56 flows along the... Figure 11 The transmission path H2, indicated by the dashed line, is transmitted to the outer wall portion 5b via the bottom 5a, and is then dissipated to the outside by the outer wall portion 5b.

[0129] In addition, such as Figure 12 As shown, in the long side direction of the bracket 53, the bracket 53 is in contact with the support body 41. Therefore, in the long side direction of the bracket 53, a portion of the heat from the heater 56 is not only dissipated from the outer wall portion 5b to the outside via the aforementioned transfer path H2, but also along the direction of the bracket 53... Figure 12 The transmission path H3, shown by the dashed line, is transmitted to the flange portion 5c via the bottom 5a and the outer wall portion 5b, and is dissipated from the flange portion 5c to the support body 41.

[0130] As described above, the outer periphery of the support 53 dissipates heat more easily than the central portion of the support 53. Therefore, as mentioned above, the heat generated per unit time in the outer periphery region RE1 is greater than the heat generated per unit time in the central region RE2. Thus, temperature uniformity of the support 53 can be achieved.

[0131] As described above, the liquid jetting head 50 includes a plurality of head chips 54, a support 53, and a planar heater 56. Each of the plurality of head chips 54 has a plurality of nozzles N for jetting ink, an example of a "liquid". The support 53 holds the plurality of head chips 54. The heater 56 is disposed on the support 53 and heats the support 53.

[0132] Here, when viewed from above, heater 56 includes an outer peripheral region RE1 along the outer edge of support 53 and a central region RE2 located further inward than the outer peripheral region RE1. Furthermore, the heat generated per unit time in the outer peripheral region RE1 is greater than the heat generated per unit time in the central region RE2.

[0133] In the liquid ejector head 50 described above, since the heat generated per unit time in the outer peripheral region RE1 is greater than that in the central region RE2, more heat can be supplied to the outer periphery of the support 53 per unit time compared to the central region. Therefore, even though the outer periphery of the support 53 dissipates heat more easily than the central region, the temperature difference between the outer periphery and the central region of the support 53 can be reduced. As a result, the temperature difference between the multiple head chips 54 can be reduced. Thus, the ink in the liquid ejector head 50 can be heated efficiently and without waste by the heater 56.

[0134] In contrast, assuming the heat output of heater 56 is uniform per unit time, for example, the heating of ink in the easily heat-dissipating parts of the liquid ejector head 50 may become insufficient, resulting in a higher probability of poor ink ejection. Furthermore, in this case, the difficult-to-heat or non-heat-requiring parts of the liquid ejector head 50 may overheat, unnecessarily increasing power consumption. Additionally, since temperature unevenness occurs within the liquid ejector head 50 between the easily heat-dissipating and difficult-to-heat-dissipate parts, differences in ink ejection characteristics will also appear, leading to a decrease in print quality.

[0135] Furthermore, examples of parts of the liquid jet head 50 that are difficult to dissipate heat include, for example, the central portion of the liquid jet head 50 when viewed from above, and the hollow portion inside the liquid jet head 50. Examples of parts of the liquid jet head 50 that do not require heating include, for example, the portion where only the discharge channel exists, and the portion where the heating object exists only on one surface of the heater 56.

[0136] In this embodiment, as described above, the heat generated per unit area of ​​the outer peripheral region RE1 is greater than the heat generated per unit area of ​​the central region RE2. Therefore, even when the driving of the outer peripheral region RE1 and the central region RE2 is controlled using a shared control system, it is possible to ensure that the heat generated per unit time of the outer peripheral region RE1 is greater than the heat generated per unit time of the central region RE2. Furthermore, in this embodiment, as described above, since the heating resistor 56d of the central region RE2 does not receive a power supply, it does not generate heat. Here, the heating resistor 56d functions as a heat transfer element that transfers heat from the outer peripheral region RE1 in the planar direction, and also functions as a spacer that defines the distance between the support 53 and the heat transfer component 57.

[0137] Furthermore, as described above, the liquid injection head 50 includes a piezoelectric element 54f and a drive circuit 54j, which serve as examples of "drive elements". The piezoelectric element 54f is a component for ejecting ink from multiple nozzles N. The drive circuit 54j is electrically connected to the piezoelectric element 54f. Moreover, the drive circuit 54j is located inside the outer peripheral region RE1 when viewed from above.

[0138] In this structure, since the heat generated in the drive circuit 54j is supplied to the central portion of the support 53, assuming the heat generation of the heater 56 is uniform per unit time, the temperature of the central portion of the support 53 tends to be extremely high compared to the outer periphery. Therefore, in this structure, it is particularly useful to make the heat generation per unit time of the outer periphery region RE1 greater than that of the central region RE2.

[0139] In this embodiment, as described above, the support 53 has a recess 53o as an example of a "connection portion". The recess 53o is thermally connected to the drive circuit 54j and overlaps with the central region RE2 when viewed from above. In such a structure, since the heat generated in the drive circuit 54j is supplied to the central portion of the support 53, assuming that the heat generated per unit time by the heater 56 is uniform, the temperature of the central portion of the support 53 tends to become extremely high compared to the outer periphery. Therefore, in such a structure, it is particularly useful to make the heat generated per unit time of the outer periphery RE1 greater than the heat generated per unit time of the central region RE2.

[0140] Furthermore, as described above, the support 53 forms part of the outer wall of the liquid injection head 50. In such a structure, since the outer periphery of the support 53 is easy to dissipate heat, it is particularly useful to make the heat generated per unit time in the outer peripheral region RE1 greater than the heat generated per unit time in the central region RE2.

[0141] As described above, the outer peripheral region RE1 surrounds the multiple nozzles N of the multiple head chips 54 in a top-down view. Therefore, it is possible to reduce the temperature difference between the multiple nozzles N of each of the multiple head chips 54.

[0142] 2. Second Implementation Method

[0143] Hereinafter, a second embodiment of the present invention will be described. In the embodiments illustrated below, elements that have the same function and effect as those in the first embodiment will be referred to by the same symbols used in the description of the first embodiment, and their detailed descriptions will be omitted as appropriate.

[0144] Figure 13 This diagram illustrates the heat distribution of the heater 56A in the second embodiment. The heater 56A is identical to the heater 56 in the first embodiment, except that it has heating resistors 56e and 56f instead of heating resistors 56c and 56d.

[0145] Heating resistors 56e and 56f are identical to heating resistors 56c and 56d, except that they are connected in series with respect to a power source (not shown). Here, heating resistor 56e is located in the outer peripheral region RE1 and is electrically connected to heating resistor 56f through the boundary between the outer peripheral region RE1 and the central region RE2. Heating resistor 56f is located in the central region RE2. Figure 13 In the example shown, the heating resistor 56f is divided into a first central region RE2a and a first central region RE2b. Alternatively, the heating resistor 56f can also be integrally formed, spanning both the first central region RE2a and the first central region RE2b.

[0146] The heating resistor 56f is configured such that the heat generated per unit area of ​​the central region RE2 is less than the heat generated per unit area of ​​the outer peripheral region RE1. That is, the resistance of the heating resistor 56e per unit area in the outer peripheral region RE1 is configured to be greater than the resistance of the heating resistor 56f per unit area in the central region RE2. Specifically, this is achieved by satisfying at least one of the following: the cross-sectional area of ​​the heating resistor 56e is smaller than the cross-sectional area of ​​the heating resistor 56f; the length of the heating resistor 56e per unit area in the outer peripheral region RE1 is longer than the length of the heating resistor 56f per unit area in the central region RE2; and the resistivity of the material constituting the heating resistor 56e is higher than the resistivity of the material constituting the heating resistor 56f. This results in the resistance of the heating resistor 56e per unit area in the outer peripheral region RE1 being greater than the resistance of the heating resistor 56f per unit area in the central region RE2. For the heating resistor 56e per unit area in the outer peripheral region RE1 to be longer than the heating resistor 56f per unit area in the central region RE2, it is possible to, for example, make the spacing between adjacent folded portions of the heating resistor 56e narrower than the spacing between adjacent folded portions of the heating resistor 56f. For example, for the heating resistor 56f to have a cross-sectional area larger than that of the heating resistor 56e, although at least one of the width and thickness of the heating resistor 56f is larger than that of the heating resistor 56e, from the viewpoint of properly functioning the heating resistor 56f as a spacer, it is preferable that the thickness of the heating resistor 56f is equal to the thickness of the heating resistor 56e, and that the width of the heating resistor 56f is larger than the width of the heating resistor 56e.

[0147] According to the second embodiment described above, similarly to the first embodiment, the liquid in the liquid jet head 50 can be heated efficiently and without waste using the heater 56A. Furthermore, the heating resistors 56e and 56f can also be electrically connected in parallel with respect to a power source (not shown). In this case, the heating resistors 56e and 56f only need to be configured in a structure opposite to the case where they are electrically connected in series with respect to a power source (not shown), and only need to be configured such that the resistance of the heating resistor 56e per unit area in the peripheral region RE1 is less than the resistance of the heating resistor 56e per unit area in the central region RE2.

[0148] 3. Third Implementation Method

[0149] The third embodiment of the present invention will now be described. In the embodiments illustrated below, elements that have the same function and effect as those in the first embodiment will be referred to by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions of each will be omitted.

[0150] Figure 14 This diagram illustrates the heat distribution of the heater 56B in the third embodiment. The heater 56B is identical to the heater 56 of the first embodiment described above, except that it has a heating resistor 56g instead of a heating resistor 56d.

[0151] Heating resistor 56g is identical to heating resistor 56d except that it heats up when energized. Here, heating resistor 56g is located in the central region RE2. Figure 13 In the example shown, the heating resistor 56f has a portion disposed in the first central region RE2a and a portion disposed in the first central region RE2b, and they are electrically connected in series. Alternatively, the heating resistor 56f can also be divided into the first central region RE2a and the first central region RE2b.

[0152] The heating resistor 56g heats up by receiving a power supply, based on the control implemented by the control unit 20 described above. In this embodiment, the control unit 20 controls the power supply to the heating resistor 56g based on the detection result of the temperature sensor 70b disposed in the central region RE2, in a manner that makes the detected temperature of the temperature sensor 70b reach a predetermined temperature. Furthermore, the control unit 20 controls the power supply to the heating resistor 56c based on the detection result of the temperature sensor 70a disposed in the outer peripheral region RE1, in a manner that makes the detected temperature of the temperature sensor 70a reach a predetermined temperature.

[0153] Here, the control unit 20 controls the power supply to the heating resistors 56c and 56g in such a way that the heat generated per unit time in the outer peripheral region RE1 is greater than the heat generated per unit time in the central region RE2. According to the third embodiment described above, similarly to the first embodiment, the liquid in the liquid jet head 50 can be heated efficiently and without waste by the heater 56B.

[0154] 4. Fourth Implementation Method

[0155] The fourth embodiment of the present invention will now be described. In the embodiments illustrated below, elements that have the same function and effect as those in the first embodiment will be referred to by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions of each will be omitted.

[0156] Figure 15 This diagram illustrates the heat distribution of the heater 56C in the fourth embodiment. The heater 56C is identical to the heater 56 of the first embodiment described above, except for its shape when viewed from above and the distribution of heat output per unit time.

[0157] like Figure 15 As shown, heater 56C is roughly quadrilateral when viewed from above. In heater 56C, the outer peripheral region RE1 includes first outer peripheral regions RE1a and RE1b, and second outer peripheral regions RE1c and RE1d.

[0158] The first outer peripheral regions RE1a and RE1b are the portions of the outer peripheral region RE1 along the two short sides of the outer edge OE2. The second outer peripheral regions RE1c and RE1d are the portions of the outer peripheral region RE1 along the two long sides of the outer edge OE2. Here, the heat generated per unit time of each of the first outer peripheral regions RE1a and RE1b is greater than the heat generated per unit time of each of the second outer peripheral regions RE1c and RE1d. Furthermore, for example, this heat generation relationship can be achieved by adjusting the resistance per unit area of ​​the heating resistor, as described in the second embodiment above.

[0159] Furthermore, in heater 56C, the central region RE2 includes first central regions RE2a and RE2b, and second central regions RE2c and RE2d. The second central region RE2c is the region between the first central region RE2a and the outer peripheral region RE1. The second central region RE2d is the region between the first central region RE2b and the outer peripheral region RE1. Here, the heat generation per unit time of each of the second central regions RE2c and RE2d is greater than the heat generation per unit time of each of the first central regions RE2a and RE2b. Moreover, this heat generation relationship is achieved, for example, as in the second embodiment described above, by adjusting the resistance per unit area of ​​the heating resistor.

[0160] According to the fourth embodiment described above, similarly to the first embodiment, the liquid in the liquid injection head 50 can be heated efficiently and without waste by means of the heater 56C. Here, as described above, the liquid injection head 50 includes a flange portion 5c. The flange portion 5c contacts the support body 41 that supports the liquid injection head 50, and protrudes relative to the heater 56C in the Y1 and Y2 directions, which are examples of the "first direction," when viewed from above. In this embodiment, as described above, the outer peripheral region RE1 includes first outer peripheral regions RE1a, RE1b and second outer peripheral regions RE1c, RE1d. The first outer peripheral regions RE1a, RE1b are located in the Y1 or Y2 direction relative to the central region RE2 when viewed from above. The second outer peripheral regions RE1c, RE1d are located in the X1 or X2 direction, which are examples of the "second direction orthogonal to the first direction," when viewed from above, relative to the central region RE2.

[0161] Furthermore, the heat generated per unit time in the first outer peripheral regions RE1a and RE1b is greater than the heat generated per unit area in the second outer peripheral regions RE1c and RE1d. Therefore, the heat supplied to the portion of the support 53 near the flange 5c per unit time is greater than the heat supplied to the portion of the support 53 away from the flange 5c per unit time. Thus, even if the portion of the support 53 near the flange 5c dissipates heat more easily than the portion away from the flange 5c, the support 53 can still be heated uniformly.

[0162] Here, as described above, the flange 5c is part of the support 53. Therefore, compared to a structure where the flange 5c and the support 53 are separate, the portion of the support 53 closer to the flange 5c is more prone to heat dissipation than the portion farther from the flange 5c.

[0163] Furthermore, as described above, the central region RE2 includes first central regions RE2a and RE2b, which are disposed between two adjacent head chips 54 among the plurality of head chips 54 when viewed from above, and second central regions RE2c and RE2d, which are different from the first central regions RE2a and RE2b. Moreover, the heat generated per unit time by the second central regions RE2c and RE2d is greater than the heat generated per unit time by the first central regions RE2a and RE2b. Therefore, compared to a structure where the heat generated per unit time by the second central regions RE2c and RE2d is less than or equal to the heat generated per unit time by the first central regions RE2a and RE2b, the temperature difference between the head chips 54 can be reduced.

[0164] 5. Variations

[0165] The methods illustrated above can be modified in various ways. The following examples illustrate specific modifications that can be applied to the methods described above. Any two or more methods selected from the following examples can be appropriately combined within the bounds of mutual non-contradiction.

[0166] 5-1. Variation Example 1

[0167] Figure 16 This is a schematic diagram of the liquid injection head 50D involved in Modification 1. The liquid injection head 50D is the same as the liquid injection head 50 of the first embodiment described above, except that it has a support 53D and a heater 56D instead of a support 53 and a heater 56.

[0168] A space 5d is provided between the support 53D and the fixing plate 55. Since the space 5d is composed of air, heat transfer is difficult. Therefore, in the heater 56D, a second region RE2 and a third region RE3, which generate less heat per unit time compared to the first region RE1, are provided at a position overlapping the space 5d when viewed from above. Here, the third region RE3 is located closer to the outer periphery of the support 53D than the first region RE1. Thus, the third region RE3 can be located closer to the outer periphery of the support 53D than the first region RE1, or the first region RE1 can be located outside the outermost periphery of the heater 56D.

[0169] 5-2. Variation Example 2

[0170] Figure 17 This is a schematic diagram of the liquid injection head 50E involved in Modification Example 2. The liquid injection head 50E is the same as the liquid injection head 50 of the first embodiment described above, except that it has a head chip 54E instead of a portion of the plurality of head chips 54, and a support 53D and a heater 56E instead of a support 53 and a heater 56.

[0171] The heat capacity of head chip 54E is less than that of head chip 54. Therefore, head chip 54E is easier to heat up compared to head chip 54. That is, head chip 54 is more difficult to heat up compared to head chip 54E. Therefore, in heater 56E, a fourth region RE4 with a smaller heat generation per unit time compared to the first region RE1 is provided at a position overlapping head chip 54E when viewed from above. Here, the heat generation per unit time of the fourth region RE4 is greater than the heat generation per unit time of the second region RE2 and the third region RE3, respectively.

[0172] 5-3. Variation Example 3

[0173] Figure 18 This is a schematic diagram of the liquid injection head 50F involved in Modification Example 3. The liquid injection head 50F is identical to the liquid injection head 50 of the first embodiment described above, except that it has a bracket 53F and a heater 56F instead of the bracket 53 and heater 56. The bracket 53F is identical to the bracket 53D described above, except that the space 5d is omitted.

[0174] In Modification 3, the emissivity of heat from the fixed plate 55 is higher than that from the nozzle plate 54c. Therefore, in the assembly consisting of the support 53F and the head chip 54, the portion overlapping the fixed plate 55 when viewed from above is easier to dissipate heat. Therefore, in the heater 56F, a first region RE1 and a fifth region RE5, which have a larger heat output per unit time compared to the second region RE2, are provided at the position where they overlap with the fixed plate 55 when viewed from above. Here, the fifth region RE5 is located further inside than the second region RE2. Thus, the fifth region RE5 can be located further inside than the second region RE2, or the second region RE2 can be located outside the innermost part of the heater 56D. Furthermore, the heat output per unit time of the fifth region RE5 can be equal to or different from that of the first region RE1.

[0175] 5-4. Variation Example 4

[0176] In the above-described manner, the shape of the holding part 5a1 when viewed from above is a shape different from a rectangle, depending on the arrangement of the four head chips 54. The shape of the holding part 5a1 when viewed from above is not limited to the above-described manner; for example, it may also be a rectangle or a roughly rectangular shape.

[0177] 5-5. Variation Example 5

[0178] In the above-described manner, the shape of the heater 56 when viewed from above is a shape different from a rectangle, depending on the arrangement of the four head chips 54. The shape of the heater 56 when viewed from above is not limited to the above-described manner; for example, it can also be rectangular or approximately rectangular.

[0179] 5-6. Variation Example 6

[0180] Although the above method illustrates a structure using a heat transfer component 57, it is not limited to this structure; for example, the heat transfer component 57 may be omitted.

[0181] 5-7. Variation Example 7

[0182] Although the above description illustrates a structure in which the liquid injection head 50 has four head chips 54, it is not limited to this structure; the number may also be two, three, or five or more. Furthermore, although in the above description the multiple head chips 54 are arranged in a staggered pattern along the long side of the head chip 54, it is not limited to this structure; the multiple head chips 54 may also be arranged in a staggered pattern along the short side of the head chip 54.

[0183] 5-8. Variation Example 8

[0184] Although the above-described embodiment illustrates a serial liquid ejection device 100 in which the support body 41 supporting the liquid ejection head 50 reciprocates, the present invention can also be applied to a row-type liquid ejection device in which multiple nozzles N are distributed across the entire width of the medium M. That is, the support body supporting the liquid ejection head 50 is not limited to a serial carriage, but can also be a structure that supports the liquid ejection head 50 in a row configuration. In this case, for example, multiple liquid ejection heads 50 are arranged in a manner that runs along the width direction of the medium M, and these multiple liquid ejection heads 50 are supported together on a single support body.

[0185] 5-9. Variation Example 9

[0186] The liquid jetting apparatus illustrated above can be used not only in printing equipment but also in various other devices such as fax machines and copiers. Of course, the applications of the liquid jetting apparatus are not limited to printing. For example, a liquid jetting apparatus for jetting solutions of color materials is used as a manufacturing apparatus for color filters in display devices such as liquid crystal display panels. Furthermore, a liquid jetting apparatus for jetting solutions of conductive materials is used as a manufacturing apparatus for wiring and electrodes in wiring substrates. Additionally, a liquid jetting apparatus for jetting solutions of organic substances related to living organisms is used as a manufacturing apparatus, for example, for manufacturing biochips.

[0187] Symbol Explanation

[0188] 5a… Bottom; 5a1… Holding part; 5a11… Heated part; 5a12… Side wall part; 5a2… Connecting part; 5b… Outer wall part; 5c… Flange part; 10… Liquid reservoir part; 20… Control unit (control section); 30… Conveying mechanism; 40… Moving mechanism; 41… Support body; 41a… Opening; 41b… Screw hole; 42… Conveyor belt; 50… Liquid injection head; 51… Flow channel structure; 51a… Flow channel component; 51b… Connecting pipe; 51c… Wiring hole; 52… Substrate unit; 52a… Circuit board; 52b… Connector; 52c… Support plate; 53… Bracket; 53a… Recess; 53b… Ink hole; 53c… Wiring hole; 53d… Recess; 53e… Hole; 53f… Hole; 53g… Screw Hole; 53h…recess; 53i…screw hole; 53j…hole; 53k…screw hole; 53l…flow channel; 53m…recess; 53n…screw hole; 53o…recess (connection part); 53p…screw hole; 54…head chip; 54_1…head chip; 54_2…head chip; 54_3…head chip; 54_4…head chip; 54a…flow channel substrate; 54b…pressure chamber substrate; 54c…nozzle plate; 54d…vibration absorber; 54e…vibrating plate; 54f…piezoelectric element; 54g…protection plate; 54h…housing; 54i…wiring substrate; 54j…drive circuit; 54k…frame; 55…fixing plate; 55a…opening; 56…heater; 56A…heater; 56B…heater; 56C…heater Device; 56a…hole; 56b…hole; 56c…heating resistor; 56d…heating resistor; 56e…heating resistor; 56f…heating resistor; 56g…heating resistor; 57…heat transfer component; 57a…hole; 57b…wiring hole; 57c…hole; 58…cover; 58a…through hole; 58b…opening; 59…pressing component; 59_1…pressing component; 59_2…pressing component; 59_3…pressing component; 59_4…pressing component; 59a…base part; 59b…bending part; 60…heat dissipation component; 60_1…heat dissipation component; 60_2…heat dissipation component; 60a…part; 60b…part; 60c…part; 70…temperature sensor; 70a…temperature sensor; 70b… Temperature sensor; 100…Liquid injection device; C…Pressure chamber; D…Drive signal; DM…Conveying direction; F1…First face; F2…Second face; FN…Nozzle face; H1…Transmission path; H2…Transmission path; H3…Transmission path; IO…Inlet; L1…First column; L2…Second column; M…Medium; N…Nozzle; Na…Connecting channel; OE…Outer edge; OE1…Outer edge; OE2…Outer edge; R…Reservoir; R1…Space; R2…Space; RE1…Outer peripheral region; RE1a…First outer peripheral region; RE1b…First outer peripheral region; RE1c…Second outer peripheral region; RE1d…Second outer peripheral region; RE2…Central region; RE2a…First central region; RE2b…First central region;RE2c…Second central region; RE2d…Second central region; Ra…Supply channel; S…Control signal.

Claims

1. A liquid injection head, characterized in that, have: Multiple head chips, each head chip having multiple nozzles for spraying liquid; A support that holds the plurality of head chips; A heater, which is planar in shape, is disposed on the support and heats the support. When viewed from above, the heater includes an outer peripheral region along the outer edge of the support and a central region located more inward than the outer peripheral region. The heat generated per unit time in the outer peripheral region is greater than the heat generated per unit time in the central region. The heat generated per unit area of ​​the outer peripheral region is greater than the heat generated per unit area of ​​the central region.

2. The liquid injection head as claimed in claim 1, wherein, The resistance of the heating resistor per unit area in the outer peripheral region is greater than the resistance of the heating resistor per unit area in the central region.

3. The liquid injection head as described in claim 1 or 2, wherein, It also includes a flange portion that contacts a support body that supports the liquid injection head and protrudes in a first direction relative to the heater when viewed from above. The outer peripheral region includes a first outer peripheral region and a second outer peripheral region. When viewed from above, the first outer peripheral region is located in the first direction relative to the central region, and the second outer peripheral region is located in the second direction orthogonal to the first direction relative to the central region when viewed from above. The heat generated per unit time in the first peripheral region is greater than the heat generated per unit area in the second peripheral region.

4. The liquid injection head as described in claim 3, wherein, The flange is part of the bracket.

5. The liquid injection head as claimed in claim 1, wherein, It also has: A drive element for spraying liquid from each of the plurality of nozzles; The driving circuit is electrically connected to the driving element. The drive circuit is positioned inside the outer peripheral region when viewed from above.

6. The liquid injection head as claimed in claim 5, wherein, The bracket has a connection portion that is thermally connected to the drive circuit. The connecting portion overlaps with the central region when viewed from above.

7. The liquid injection head as claimed in claim 1, wherein, The support forms part of the outer wall of the liquid jet head.

8. The liquid injection head as claimed in claim 1, wherein, The outer peripheral region surrounds the plurality of nozzles of the plurality of head chips when viewed from above.

9. The liquid injection head as claimed in claim 1, wherein, The central region includes a first central region and a second central region. The first central region, when viewed from above, is positioned between two adjacent head chips among the plurality of head chips. The second central region differs from the first central region when viewed from above. The heat generated per unit time in the second central region is greater than that generated per unit time in the first central region.

10. The liquid injection head as claimed in claim 1, wherein, The heater has a heating resistor disposed in the central region and a heating resistor disposed in the outer peripheral region. The heating resistor located in the central area is not energized. The thickness of the heating resistor located in the central region is equal to the thickness of the heating resistor located in the outer peripheral region.

11. A liquid injection device, characterized in that, have: The liquid injection head according to any one of claims 1 to 10; The control unit controls the driving of the heater.

12. The liquid injection device as claimed in claim 11, wherein, It also includes a support body that supports the liquid injection head and is made of a metal material.

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