Liquid ejection head and liquid ejection device

Abstract

To provide a technique that enables a liquid discharge head to suppress or prevent heat transmitted from liquid in pressure chambers to a detection resistor from being radiated from the detection resistor.SOLUTION: A liquid discharge head comprises: a pressure chamber substrate provided with a plurality of pressure chambers; an individual electrode provided individually for the plurality of pressure chambers; a common electrode provided in common for the plurality of pressure chambers; a piezoelectric body provided between the individual electrode and the common electrode to apply pressure to liquid in the pressure chambers; drive wiring that is electrically connected to the individual electrode and the common electrode, and applies a voltage for driving the piezoelectric body; a detection resistor that is formed of the same materials as any of the individual electrode, the common electrode and the drive wiring for detecting temperature of the liquid in the pressure chambers; and a first layer that is provided on a surface opposite to a surface facing the pressure chamber substrate in the detection resistor, and has a lower thermal conductivity than the detection resistor.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] A liquid ejection device is known that has a temperature detection unit on the side of a carriage on which a liquid ejection head is mounted (for example, Patent Document 1). This liquid ejection device changes the number of maintenance drive pulses applied to the piezoelectric element based on the environmental temperature detected by the temperature detection unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-104916 Summary of the Invention [Problem to be solved by the invention]

[0004] However, providing a temperature detection unit outside the liquid ejection head may reduce the accuracy of detecting the temperature of the ink inside the pressure chamber. Therefore, there is a demand for locating the temperature detection unit near the pressure chamber inside the liquid ejection head. The inventors have therefore discovered a new method for obtaining the temperature of the ink inside the pressure chamber by locating a resistive wiring inside the liquid ejection head and using the correspondence between the resistance value of the resistive wiring and the temperature. However, there is a demand for improving the accuracy of temperature detection using resistive wiring located inside the liquid ejection head. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a liquid ejection head comprising: a pressure chamber substrate having a plurality of pressure chambers, individual electrodes provided individually for the plurality of pressure chambers, a common electrode provided in common to the plurality of pressure chambers, a piezoelectric body provided between the individual electrodes and the common electrode for applying pressure to liquid in the pressure chambers, drive wiring electrically connected to the individual electrodes and the common electrode for applying a voltage to drive the piezoelectric body, a detection resistor formed of the same material as any of the individual electrodes, the common electrode, and the drive wiring for detecting the temperature of the liquid in the pressure chambers, and a first layer of the detection resistor provided on a surface opposite to a surface facing the pressure chamber substrate, the first layer having a lower thermal conductivity than the detection resistor.

[0006] According to a second aspect of the present disclosure, there is provided a liquid ejection device, comprising: the liquid ejection head according to the first aspect; and a control unit that controls the ejection operation of the liquid ejection head. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a liquid ejection device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing the functional configuration of the liquid ejection device. [Figure 3] FIG. 2 is an exploded perspective view showing the configuration of a liquid ejection head. [Figure 4] FIG. 2 is an explanatory diagram showing the configuration of a liquid ejection head in a plan view. [Figure 5] 5 is a cross-sectional view showing the VV position in FIG. 4. [Figure 6] FIG. 5 is an enlarged cross-sectional view of a part of FIG. 4. [Figure 7] FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6. [Figure 8] FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 6. [Figure 9] FIG. 2 is an explanatory diagram showing an example of a material that can be used for a low thermal conductive layer. [Figure 10] FIG. 3 is an explanatory diagram showing a cross-sectional structure near a detection resistor and a low thermal conductive layer. [Figure 11] FIG. 10 is a cross-sectional view showing the structure in the vicinity of a detection resistor of a liquid ejection head according to a second embodiment of the present disclosure. [Figure 12] FIG. 10 is a cross-sectional view showing the structure in the vicinity of a detection resistor of a liquid ejection head according to a third embodiment of the present disclosure. [Figure 13] FIG. 10 is a cross-sectional view showing the structure in the vicinity of a detection resistor of a liquid ejection head according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is an explanatory diagram showing a schematic configuration of a liquid ejection device 500 according to a first embodiment of the present disclosure. In this embodiment, the liquid ejection device 500 is an inkjet printer that ejects ink, an example of a liquid, onto printing paper P to form an image. Instead of printing paper P, the liquid ejection device 500 may eject ink onto any type of medium, such as a resin film or fabric. X, Y, and Z shown in FIG. 1 and subsequent figures represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are also referred to as the X-axis direction, Y-axis direction, and Z-axis direction. When specifying a direction, positive and negative signs are used in combination, with a positive direction indicated by "+" and a negative direction indicated by "-." The direction indicated by the arrow in each figure is referred to as the + direction and the opposite direction as the - direction. In this embodiment, the Z direction coincides with the vertical direction, with the +Z direction indicating a vertically downward direction and the -Z direction indicating a vertically upward direction. Furthermore, when the positive and negative directions are not limited, the following description will be given assuming that the three X, Y, and Z are the X-axis, Y-axis, and Z-axis.

[0009] As shown in FIG. 1 , the liquid ejection device 500 includes a liquid ejection head 510, a temperature acquisition unit 400, an ink tank 550, a transport mechanism 560, a movement mechanism 570, and a control unit 580. The liquid ejection head 510 includes a detection resistor 401. In this embodiment, the temperature acquisition unit 400 is provided in the liquid ejection head 510. The liquid ejection head 510 has multiple nozzles formed therein and ejects ink of four colors, for example, black, cyan, magenta, and yellow, in the +Z direction to form an image on printing paper P. The liquid ejection head 510 is mounted on a carriage 572 and moves back and forth in the main scanning direction along with the movement of the carriage 572. In this embodiment, the main scanning direction is the +X direction and the −X direction. The liquid ejection head 510 is not limited to the four colors and may eject ink of any color, such as light cyan, light magenta, or white.

[0010] The ink tank 550 contains ink to be ejected from the liquid ejection head 510. The ink tank 550 is connected to the liquid ejection head 510 by a resin tube 552. The ink in the ink tank 550 is supplied to the liquid ejection head 510 via the tube 552. Instead of the ink tank 550, a bag-shaped liquid pack made of a flexible film may be provided.

[0011] The transport mechanism 560 transports the printing paper P in the sub-scanning direction. The sub-scanning direction is a direction that intersects with the X-axis direction, which is the main scanning direction, and in this embodiment, is the +Y direction and the -Y direction. The transport mechanism 560 includes a transport rod 564 to which three transport rollers 562 are attached, and a transport motor 566 that rotates the transport rod 564. The transport motor 566 rotates the transport rod 564, thereby transporting the printing paper P in the +Y direction, which is the sub-scanning direction. The number of transport rollers 562 is not limited to three and may be any number. Furthermore, a configuration may be provided with multiple transport mechanisms 560.

[0012] The movement mechanism 570 includes a carriage 572, a conveyor belt 574, a movement motor 576, and a pulley 577. The carriage 572 carries a liquid ejection head 510 that is ready to eject ink. The carriage 572 is fixed to the conveyor belt 574. The conveyor belt 574 is stretched between the movement motor 576 and the pulley 577. When the movement motor 576 is driven to rotate, the conveyor belt 574 moves back and forth in the main scanning direction. As a result, the carriage 572, which is fixed to the conveyor belt 574, also moves back and forth in the main scanning direction.

[0013] The control unit 580 controls the entire liquid ejection device 500. The control unit 580 controls, for example, the reciprocating movement of the carriage 572 in the main scanning direction, the transport movement of the printing paper P in the sub-scanning direction, and the ejection movement of the liquid ejection head 510. The control unit 580 includes, for example, one or more processing circuits such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits such as a semiconductor memory.

[0014] Fig. 2 is a block diagram showing the functional configuration of the liquid ejection device 500. In Fig. 2, the configurations of the ink tank 550, the transport mechanism 560, and the movement mechanism 570 are omitted. The liquid ejection head 510 of this embodiment is provided with a piezoelectric element 300, a detection resistor 401, and a temperature acquisition unit 400.

[0015] The piezoelectric element 300 generates a pressure change in the ink within the pressure chamber of the liquid ejection head 510. The detection resistor 401 is a resistive wiring used to detect the temperature of the pressure chamber, as will be described later. The temperature acquisition unit 400 estimates the temperature of the ink within the pressure chamber by detecting the temperature of the detection resistor 401 using the characteristic that the electrical resistance value of resistive wiring made of metal, semiconductor, or the like changes with temperature. The temperature acquisition unit 400 includes a current application circuit 430, a voltage detection circuit 440, a temperature calculation unit 450, and a memory unit 460.

[0016] The current application circuit 430 applies a current to the detection resistor 401. In this embodiment, the current application circuit 430 is a constant current circuit that applies a predetermined constant current to the detection resistor 401. The voltage detection circuit 440 detects the voltage value of the voltage generated in the detection resistor 401 by the application of the current.

[0017] The storage unit 460 may be, for example, a nonvolatile memory such as an EEPROM that can be erased with an electrical signal, a nonvolatile memory such as a One-Time-PROM or an EPROM that can be erased with ultraviolet light, or a non-erasable nonvolatile memory such as a PROM. The storage unit 460 stores various programs for realizing the functions provided by the temperature acquisition unit 400 in this embodiment. The CPU of the temperature acquisition unit 400 executes the various programs stored in the storage unit 460, thereby functioning as the temperature calculation unit 450.

[0018] The temperature calculation unit 450 acquires the electrical resistance value of the detection resistor 401 and calculates the temperature of the pressure chamber. Specifically, the temperature calculation unit 450 acquires the resistance value of the detection resistor 401 based on the current value of the current applied to the detection resistor 401 from the current application circuit 430 and the voltage value of the voltage generated in the detection resistor 401 by the application of the current. The temperature calculation unit 450 calculates the temperature of the pressure chamber using the acquired resistance value of the detection resistor 401 and a temperature calculation formula stored in the storage unit 460. The temperature calculation formula indicates the correspondence relationship between the electrical resistance value of the detection resistor 401 and the temperature.

[0019] The temperature acquisition unit 400 outputs the detected temperature of the pressure chamber to the control unit 580. The control unit 580 outputs a drive signal based on the temperature of the pressure chamber acquired from the temperature acquisition unit 400 to the liquid ejection head 510 to drive the piezoelectric element 300, thereby controlling the ejection of ink onto the printing paper P.

[0020] The detailed configuration of the liquid ejection head 510 will be described with reference to FIGS. 3 to 5. FIG. 3 is an exploded perspective view showing the configuration of the liquid ejection head 510. FIG. 4 is an explanatory diagram showing the configuration of the liquid ejection head 510 in a plan view. FIG. 4 shows the configuration around the pressure chamber substrate 10 in the liquid ejection head 510. In FIG. 4, the protection substrate 30 and the case member 40 are omitted from illustration to facilitate understanding of the technology. FIG. 5 is a cross-sectional view showing the VV position in FIG. 4.

[0021] As shown in FIG. 3, the liquid ejection head 510 includes a pressure chamber substrate 10, a communication plate 15, a nozzle plate 20, a compliance substrate 45, a protective substrate 30, a case member 40, a vibration plate 50, and a relay substrate 120, and further includes a piezoelectric element 300 shown in FIG. 4. The pressure chamber substrate 10, the communication plate 15, the nozzle plate 20, the compliance substrate 45, the vibration plate 50, the piezoelectric element 300, the protective substrate 30, and the case member 40 are laminated members, and are stacked to form the liquid ejection head 510. In the present disclosure, the direction in which the laminated members that form the liquid ejection head 510 are stacked is also referred to as the "stacking direction." In this embodiment, the stacking direction coincides with the Z-axis direction.

[0022] The pressure chamber substrate 10 is formed using, for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, or the like. As shown in FIG. 4 , the pressure chamber substrate 10 has a plurality of pressure chambers 12 arranged along a predetermined direction. The direction in which the plurality of pressure chambers 12 are arranged is also referred to as the "arrangement direction." The pressure chambers 12 are formed in a substantially rectangular shape in which the length in the X-axis direction is longer than the length in the Y-axis direction in a plan view. However, the shape of the pressure chambers 12 is not limited to a rectangular shape and may be a parallelogram, polygon, circle, oval, or the like. An oval shape refers to a shape that is based on a rectangular shape and has semicircular ends at both longitudinal ends, and includes a rounded rectangle, an ellipse, an egg shape, and the like.

[0023] In this embodiment, the pressure chambers 12 are arranged in two rows, each with its arrangement direction aligned in the Y-axis direction. In the example of FIG. 4, two pressure chamber rows are formed in the pressure chamber substrate 10: a first pressure chamber row L1 with its arrangement direction aligned in the Y-axis direction, and a second pressure chamber row L2 with its arrangement direction aligned in the Y-axis direction. The first pressure chamber row L1 and the second pressure chamber row L2 are arranged on either side of the relay substrate 120. Specifically, the second pressure chamber row L2 is arranged on the opposite side of the first pressure chamber row L1, across the relay substrate 120, in a direction intersecting the arrangement direction of the first pressure chamber row L1. The direction intersecting the arrangement direction is also referred to as the "intersecting direction." In the example of FIG. 4, the intersecting direction is the X-axis direction, and the second pressure chamber row L2 is arranged in the -X direction relative to the first pressure chamber row L1, across the relay substrate 120. The pressure chambers 12 do not necessarily have to be arranged in a straight line, but may be arranged in a staggered arrangement along the Y-axis direction, in which every other pressure chamber 12 is staggered in the intersecting direction, for example.

[0024] The pressure chambers 12 belonging to the first pressure chamber row L1 and the pressure chambers 12 belonging to the second pressure chamber row L2 are arranged so that their positions in the arrangement direction coincide with each other and that they are adjacent to each other in the intersecting direction. In each pressure chamber row, the pressure chambers 12 adjacent to each other in the Y-axis direction are partitioned by partition walls 11 shown in FIG. 9, as will be described later.

[0025] As shown in FIG. 3, a communication plate 15, a nozzle plate 20, and a compliance substrate 45 are stacked on the +Z direction side of the pressure chamber substrate 10. The communication plate 15 is a flat plate-like member made of, for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, or a metal substrate. Examples of metal substrates include a stainless steel substrate. As shown in FIG. 5, the communication plate 15 is provided with a nozzle communication passage 16, a first manifold portion 17, a second manifold portion 18, and a supply communication passage 19. It is preferable that the communication plate 15 be made of a material with approximately the same thermal expansion coefficient as that of the pressure chamber substrate 10. This makes it possible to suppress warping of the pressure chamber substrate 10 and the communication plate 15 due to differences in thermal expansion coefficients when the temperatures of the pressure chamber substrate 10 and the communication plate 15 change.

[0026] As shown in Fig. 5, the nozzle communication passage 16 is a flow path that communicates between the pressure chambers 12 and the nozzles 21. The first manifold portion 17 and the second manifold portion 18 function as part of a manifold 100 that serves as a common liquid chamber through which the multiple pressure chambers 12 communicate. The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the Z-axis direction. Furthermore, as shown in Fig. 5, the second manifold portion 18 is provided on the surface of the communication plate 15 on the +Z direction side, without penetrating the communication plate 15 in the Z-axis direction.

[0027] As shown in FIG. 5 , the supply communication passage 19 is a flow path connected to a pressure chamber supply path 14 provided in the pressure chamber substrate 10. The pressure chamber supply path 14 is a flow path connected to one end of the pressure chamber 12 in the X-axis direction via a throttle portion 13. The throttle portion 13 is a flow path provided between the pressure chamber 12 and the pressure chamber supply path 14. The throttle portion 13 has an inner wall that protrudes further than the pressure chamber 12 and the pressure chamber supply path 14, and is formed to have a narrower flow path than the pressure chamber 12 and the pressure chamber supply path 14. As a result, the throttle portion 13 is set to have a higher flow path resistance than the pressure chamber 12 and the pressure chamber supply path 14. Therefore, even if pressure is applied to the pressure chamber 12 by the piezoelectric element 300 during ink ejection, it is possible to reduce or prevent ink from flowing back into the pressure chamber supply path 14 inside the pressure chamber 12. There are multiple supply communication passages 19, which are arranged in the Y-axis direction, i.e., the arrangement direction, and are individually provided for each pressure chamber 12. The supply communication passage 19 and the pressure chamber supply passage 14 connect the second manifold portion 18 to each pressure chamber 12, and supply ink in the manifold 100 to each pressure chamber 12.

[0028] The nozzle plate 20 is provided on the opposite side of the communicating plate 15 from the pressure chamber substrate 10, i.e., on the surface of the communicating plate 15 in the +Z direction. The material of the nozzle plate 20 is not particularly limited, and examples thereof include a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, and a metal substrate. Examples of metal substrates include a stainless steel substrate. The nozzle plate 20 can also be made of an organic material such as a polyimide resin. However, it is preferable to use a material for the nozzle plate 20 with approximately the same thermal expansion coefficient as the communicating plate 15. This makes it possible to suppress warping of the nozzle plate 20 and the communicating plate 15 due to differences in thermal expansion coefficients when the temperatures of the nozzle plate 20 and the communicating plate 15 change.

[0029] A plurality of nozzles 21 are formed in the nozzle plate 20. Each nozzle 21 is connected to a corresponding pressure chamber 12 via a nozzle communication passage 16. As shown in FIG. 3, the plurality of nozzles 21 are arranged along the arrangement direction of the pressure chambers 12, i.e., the Y-axis direction. The nozzle plate 20 is provided with two nozzle rows, each of which is provided with a plurality of nozzles 21. The two nozzle rows are provided corresponding to the first pressure chamber row L1 and the second pressure chamber row L2, respectively.

[0030] As shown in FIG. 5 , the compliance substrate 45 is provided together with the nozzle plate 20 on the side opposite the pressure chamber substrate 10 across the communicating plate 15, i.e., on the surface of the communicating plate 15 on the +Z direction side. The compliance substrate 45 is provided around the nozzle plate 20 and covers the openings of the first manifold section 17 and the second manifold section 18 provided in the communicating plate 15. In this embodiment, the compliance substrate 45 includes a sealing film 46 made of a flexible thin film and a fixed substrate 47 made of a hard material such as metal. As shown in FIG. 5 , the region of the fixed substrate 47 facing the manifold 100 forms an opening 48 that is completely removed in the thickness direction. Therefore, one side of the manifold 100 forms a compliance section 49 that is sealed only by the sealing film 46.

[0031] As shown in Fig. 5, a vibration plate 50 and a piezoelectric element 300 are laminated on the side of the pressure chamber substrate 10 opposite the nozzle plate 20, etc., i.e., on the surface of the pressure chamber substrate 10 on the -Z direction side. The piezoelectric element 300 flexes and deforms the vibration plate 50, causing a pressure change in the ink inside the pressure chamber 12. In Fig. 5, the configuration of the piezoelectric element 300 is shown in a simplified manner to make the technology easier to understand. The vibration plate 50 is provided on the +Z direction side of the piezoelectric element 300, and the pressure chamber substrate 10 is provided on the +Z direction side of the vibration plate 50.

[0032] As shown in FIG. 5 , a protective substrate 30 having substantially the same size as the pressure chamber substrate 10 in a plan view is bonded to the surface of the pressure chamber substrate 10 on the −Z direction side with an adhesive or the like. The protective substrate 30 includes a lid portion 30T, a wall portion 30W, a holding portion 31, and a through-hole 32. The holding portion 31 is a space defined by the lid portion 30T and the wall portion 30W, and protects the piezoelectric elements 300. The holding portion 31 of the protective substrate 30 is provided for each row of the piezoelectric elements 300 arranged in the arrangement direction. In this embodiment, two holding portions 31 are formed adjacent to each other in the X-axis direction. The through-hole 32 extends along the Y-axis direction between the two holding portions 31 and penetrates the protective substrate 30 along the Z-axis direction.

[0033] 5, a case member 40 is fixed onto the protective substrate 30. The case member 40 forms a manifold 100, which communicates with the multiple pressure chambers 12, together with the communication plate 15. The case member 40 has approximately the same outer shape as the communication plate 15 in a plan view, and is joined so as to cover the protective substrate 30 and the communication plate 15.

[0034] The case member 40 has a storage section 41, a supply port 44, a third manifold section 42, and a connection port 43. The storage section 41 is a space deep enough to store the pressure chamber substrate 10 and the protection substrate 30. The third manifold section 42 is a space formed in the case member 40 on both sides of the storage section 41 in the X-axis direction. The third manifold section 42 is connected to the first manifold section 17 and the second manifold section 18 provided on the communication plate 15, thereby forming a manifold 100. The manifold 100 has an elongated shape that is continuous along the Y-axis direction. The supply port 44 communicates with the manifolds 100 and supplies ink to each manifold 100. The connection port 43 is a through hole that communicates with the through hole 32 of the protection substrate 30, and a relay substrate 120 is inserted through the through hole 43.

[0035] 5, ink supplied from the ink tank 550 shown in Fig. 1 is taken in through the supply port 44 shown in Fig. 5, and the internal flow paths from the manifold 100 to the nozzles 21 are filled with ink. Then, a voltage based on a drive signal is applied to each of the piezoelectric elements 300 corresponding to the plurality of pressure chambers 12. This causes the vibration plate 50 to flex and deform together with the piezoelectric elements 300, increasing the pressure inside each pressure chamber 12 and causing ink droplets to be ejected from each nozzle 21.

[0036] The configurations of the piezoelectric element 300 and the detection resistor 401 will be described with reference to Figures 4 and 5 as well as Figures 6 to 8. Figure 6 is an enlarged cross-sectional view showing the range AR in Figure 4. Figure 7 is a cross-sectional view showing the position VII-VII in Figure 6. Figure 8 is a cross-sectional view showing the position VIII-VIII in Figure 6. As shown in Figure 6, the liquid ejection head 510 has, on the -Z direction side of the pressure chamber substrate 10, not only the vibration plate 50 and the piezoelectric element 300, but also individual lead electrodes 91, common lead electrodes 92, measurement lead electrodes 93, and the detection resistor 401.

[0037] As shown in FIG. 7, the diaphragm 50 includes an elastic film 55 made of silicon oxide (SiO2) provided on the pressure chamber substrate 10, and an insulating film 56 made of zirconium oxide (ZrO2) provided on the elastic film 55. The flow paths formed in the pressure chamber substrate 10, such as the pressure chambers 12, are formed by anisotropically etching the pressure chamber substrate 10 from the surface on the +Z direction side. The elastic film 55 forms the surface on the -Z direction side of the flow paths of the pressure chambers 12, etc. Note that the diaphragm 50 may be made up of, for example, either the elastic film 55 or the insulating film 56, or may include other films in addition to the elastic film 55 and the insulating film 56. Examples of materials for the other films include silicon and silicon nitride.

[0038] The piezoelectric element 300 applies pressure to the pressure chamber 12. As shown in Fig. 7, the piezoelectric element 300 has a first electrode 60, a piezoelectric body 70, and a second electrode 80. As shown in Fig. 7, the first electrode 60, the piezoelectric body 70, and the second electrode 80 are stacked in this order from the +Z direction side to the -Z direction side along the stacking direction. The piezoelectric body 70 is provided between the first electrode 60 and the second electrode 80 in the stacking direction in which the first electrode 60, the second electrode 80, and the piezoelectric body 70 are stacked.

[0039] The first electrode 60 and the second electrode 80 are both electrically connected to the relay substrate 120 shown in FIG. 5 . The first electrode 60 and the second electrode 80 apply a voltage corresponding to a drive signal to the piezoelectric body 70. A drive voltage that varies depending on the amount of ink ejected is supplied to the first electrode 60, and a constant reference voltage signal is supplied to the second electrode 80 regardless of the amount of ink ejected. When the piezoelectric element 300 is driven, a potential difference occurs between the first electrode 60 and the second electrode 80, causing the piezoelectric body 70 to deform. The deformation of the piezoelectric body 70 causes the vibration plate 50 to deform or vibrate, changing the volume of the pressure chamber 12. The change in volume of the pressure chamber 12 applies pressure to the ink contained in the pressure chamber 12, causing ink to be ejected from the nozzle 21 via the nozzle communication passage 16.

[0040] The first electrodes 60 are individual electrodes provided for the multiple pressure chambers 12. As shown in FIG. 7, the first electrodes 60 are provided on the opposite side of the piezoelectric body 70 from the second electrode 80, i.e., on the +Z direction side of the piezoelectric body 70, below the piezoelectric body 70. The first electrodes 60 are formed to a thickness of, for example, approximately 80 nanometers. The first electrodes 60 are formed from a conductive material, for example, a metal such as platinum (Pt), iridium (Ir), gold (Au), or titanium (Ti), or a conductive metal oxide such as indium tin oxide (ITO). The first electrodes 60 may be formed by laminating multiple materials, such as platinum (Pt), iridium (Ir), gold (Au), or titanium (Ti). In this embodiment, platinum (Pt) is used as the first electrode 60.

[0041] As shown in FIG. 4, the piezoelectric body 70 has a predetermined width in the X-axis direction and extends along the arrangement direction of the pressure chambers 12, i.e., the Y-axis direction. As shown in FIG. 7, an end 70a of the piezoelectric body 70 in the +X direction is covered with a wiring portion 96 formed at the same time as the individual lead electrode 91. The thickness of the piezoelectric body 70 is, for example, approximately 1000 to 4000 nanometers. The piezoelectric body 70 may be a crystalline film with a perovskite structure, so-called perovskite crystal, made of a ferroelectric ceramic material exhibiting electromechanical transduction and formed on the first electrode 60. Examples of the material for the piezoelectric body 70 include ferroelectric piezoelectric materials such as lead zirconate titanate (PZT), and materials to which a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide is added. Specifically, lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZrO3), lead lanthanum titanate ((Pb,La),TiO3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O3), lead magnesium zirconium titanate (Pb(Zr,Ti)(Mg,Nb)O3), etc. In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric body 70.

[0042] The material of the piezoelectric body 70 is not limited to lead-based piezoelectric materials containing lead, and lead-free piezoelectric materials can also be used. Examples of lead-free piezoelectric materials include bismuth ferrite ((BiFeO3), abbreviated as "BFO"), barium titanate ((BaTiO3), abbreviated as "BT"), potassium sodium niobate ((K,Na)(NbO3), abbreviated as "KNN"), potassium sodium lithium niobate ((K,Na,Li)(NbO3)), potassium sodium lithium tantalate niobate ((K,Na,Li)(Nb,Ta)O3), bismuth potassium titanate ((Bi1 / 2K1 / 2)TiO3, abbreviated as "BKT"), bismuth sodium titanate ((Bi1 / 2Na1 / 2)TiO3, abbreviated as "BNT"), manganese dioxide (MgO3), ... Examples include bismuth phosphate (BiMnO3, abbreviated as "BM"), composite oxides containing bismuth, potassium, titanium, and iron and having a perovskite structure (x[(BixK1-x)TiO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), composite oxides containing bismuth, iron, barium, and titanium and having a perovskite structure ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), and oxides to which metals such as manganese, cobalt, and chromium are added ((1-x)[Bi(Fe1-yMy)O3]-x[BaTiO3] (M is Mn, Co, or Cr)).

[0043] As shown in FIG. 4, the second electrode 80 is a common electrode provided for the multiple pressure chambers 12. The second electrode 80 has a predetermined width in the X-axis direction and extends along the arrangement direction of the pressure chambers 12, i.e., the Y-axis direction. As shown in FIG. 7, the second electrode 80 is provided on the opposite side of the piezoelectric body 70 from the first electrode 60, i.e., on the −Z direction side of the piezoelectric body 70 and above the piezoelectric body 70. The material of the second electrode 80 is not particularly limited, but similar to the first electrode 60, conductive materials such as metals such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti), and conductive metal oxides such as indium tin oxide (ITO) are used. Alternatively, the second electrode 80 may be formed by stacking multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti). In this embodiment, iridium (Ir) is used as the second electrode 80.

[0044] A wiring portion 85 is provided further toward the −X direction side than the −X direction end portion 80b of the second electrode 80. The wiring portion 85 is in the same layer as the second electrode 80 but is electrically discontinuous with the second electrode 80. The wiring portion 85 is formed from the −X direction end portion 70b of the piezoelectric body 70 to the −X direction end portion 60b of the first electrode 60, with a gap between them and the end portion 80b of the second electrode 80. A wiring portion 85 is provided for each piezoelectric element 300, and multiple wiring portions 85 are arranged at predetermined intervals along the Y axis direction. The wiring portion 85 is preferably formed in the same layer as the second electrode 80. This simplifies the manufacturing process of the wiring portion 85 and reduces costs. However, the wiring portion 85 may be formed in a layer different from that of the second electrode 80.

[0045] 6 and 7, an individual lead electrode 91 is electrically connected to the first electrode 60, which is an individual electrode, and an extension portion 92a and an extension portion 92b of a common lead electrode 92 are electrically connected to the second electrode 80, which is a common electrode. The individual lead electrode 91 and the common lead electrode 92 function as drive wiring for applying a voltage to the piezoelectric body 70 to drive the piezoelectric body 70. In this embodiment, the power supply circuit for supplying power to the piezoelectric body 70 via the drive wiring and the current application circuit 430 for supplying power to the detection resistor 401 are different circuits.

[0046] The individual lead electrode 91 and the common lead electrode 92 are made of a conductive material, such as gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), or aluminum (Al). In this embodiment, gold (Au) is used for the individual lead electrode 91 and the common lead electrode 92. The individual lead electrode 91 and the common lead electrode 92 may also have an adhesion layer that improves adhesion to the first electrode 60, the second electrode 80, and the diaphragm 50.

[0047] The individual lead electrode 91 and the common lead electrode 92 are formed in the same layer so as to be electrically discontinuous. This simplifies the manufacturing process and reduces costs compared to when the individual lead electrode 91 and the common lead electrode 92 are formed separately. The individual lead electrode 91 and the common lead electrode 92 may be formed in different layers.

[0048] 6, an individual lead electrode 91 is provided for each first electrode 60. As shown in Fig. 7, the individual lead electrode 91 is connected to the vicinity of the end 60b of the first electrode 60 via a wiring portion 85, and is drawn out onto the diaphragm 50 in the -X direction.

[0049] 4, the common lead electrode 92 extends along the Y-axis direction, is bent at both ends in the Y-axis direction, and is drawn out in the −X direction. The common lead electrode 92 has an extension portion 92a and an extension portion 92b that extend along the Y-axis direction. As shown in FIGS. 4 and 5, the individual lead electrodes 91 and the common lead electrode 92 extend so as to be exposed in through holes 32 formed in the protection substrate 30, and are electrically connected to the relay substrate 120 within the through holes 32.

[0050] The relay substrate 120 is formed of, for example, a flexible substrate (FPC: Flexible Printed Circuit). The relay substrate 120 has a plurality of wirings formed thereon for connection to the control unit 580 and a power supply circuit (not shown). Note that instead of an FPC, any flexible substrate such as an FFC (Flexible Flat Cable) may be used. An integrated circuit 121 having a switching element is mounted on the relay substrate 120. A signal for driving the piezoelectric element 300 is input to the integrated circuit 121. The integrated circuit 121 controls the timing at which the signal for driving the piezoelectric element 300 is supplied to the first electrode 60 based on the input signal. This controls the timing at which the piezoelectric element 300 is driven and the amount of drive of the piezoelectric element 300.

[0051] As shown in FIG. 4, a detection resistor 401 is further provided on the surface of the diaphragm 50 on the -Z direction side. As shown in FIG. 4, in this embodiment, the detection resistor 401 is continuously formed so as to surround the periphery of the first pressure chamber row L1 and the second pressure chamber row L2 in a plan view. In the example of FIG. 4, the detection resistor 401 is formed in a so-called meandering pattern, which makes multiple trips near the first pressure chamber row L1 and the second pressure chamber row L2. This configuration can improve the accuracy of detection of the temperature of ink in the pressure chambers 12 by the detection resistor 401. However, the detection resistor 401 is not limited to a meandering pattern and may be formed in any shape, such as a straight line.

[0052] 7, the detection resistor 401 is arranged so as to pass near the ink flow path in the pressure chamber substrate 10 in a cross-sectional view. In this embodiment, the detection resistor 401 is arranged so as to pass on the -Z direction side of the vibration plate 50 with respect to the throttle portion 13 of each pressure chamber 12. This makes it possible to detect the temperature of the ink in the pressure chamber 12 with higher accuracy than when the detection resistor 401 is arranged at a position farther away from the pressure chamber 12.

[0053] The material of the detection resistor 401 is a material whose electrical resistance value is temperature dependent, and can be, for example, gold (Au), platinum (Pt), iridium (Ir), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), etc. Of these, platinum (Pt) is suitable for use as the material of the detection resistor 401 from the viewpoints of its large temperature-dependent change in electrical resistance, stability, and high accuracy.

[0054] 7, in this embodiment, the detection resistor 401 is formed in the same layer as the first electrode 60 in the stacking direction, and is electrically discontinuous with the first electrode 60. The detection resistor 401 is formed together with the first electrode 60 in the process of forming the first electrode 60. The material of the detection resistor 401 is platinum (Pt), the same as the first electrode 60, and the thickness of the detection resistor 401 is about 80 nanometers, the same as the first electrode 60. However, this is not limiting, and the detection resistor 401 may be formed separately from the first electrode 60, or may be formed together with a layer different from that of the first electrode 60.

[0055] As shown in FIG. 7 , in this embodiment, the detection resistor 401 is laminated on top of an insulating layer. The detection resistor 401 is formed on the diaphragm 50, and an insulating film 56 is provided in contact with the surface of the detection resistor 401 facing the pressure chamber. The insulating layer provided on the surface of the detection resistor 401 facing the pressure chamber is also referred to as the “second layer.” In this embodiment, the second layer is made of ZrO2. The second layer does not necessarily need to be in contact with the detection resistor 401. For example, an adhesion layer made of, for example, Ti may be provided between the detection resistor 401 and the low thermal conductivity layer 402 to improve adhesion between the detection resistor 401 and the insulating layer. The second layer may also be omitted.

[0056] FIG. 6 shows the measurement lead electrodes 93, including the measurement lead electrodes 93a and 93b. The measurement lead electrodes 93 function as a connection portion that electrically connects the detection resistor 401 and the relay board 120. One end of the detection resistor 401 is electrically connected to the measurement lead electrode 93a via a contact hole 93H. Although not shown, the other end of the detection resistor 401 is similarly connected to the measurement lead electrode 93b via the contact hole 93H. This enables the temperature calculation unit 450 to detect the electrical resistance value of the detection resistor 401. Note that the connection between the measurement lead electrodes 93 and the detection resistor 401 is not limited to the contact hole 93H. For example, the measurement lead electrode 93 may be stacked on the detection resistor 401, or other methods may be used to electrically connect the measurement lead electrodes 93 and the detection resistor 401.

[0057] In this embodiment, the measurement lead electrode 93 is formed in the same layer as the individual lead electrode 91 and the common lead electrode 92, and is formed so as to be electrically discontinuous. The material of the measurement lead electrode 93 is a conductive material, such as gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), aluminum (Al), etc. In this embodiment, gold (Au) is used as the measurement lead electrode 93. The material of the measurement lead electrode 93 is the same material as the individual lead electrode 91 and the common lead electrode 92.

[0058] 7, in this embodiment, a low thermal conductive layer 402 is laminated on the detection resistor 401. Specifically, the low thermal conductive layer 402 is provided on the surface of the detection resistor 401 opposite to the surface facing the pressure chamber substrate 10, i.e., on the surface on the -Z direction side. The low thermal conductive layer 402 has a lower thermal conductivity than the detection resistor 401. The low thermal conductive layer 402 is also referred to as the "first layer."

[0059] The low thermal conductive layer 402 is laminated only on the detection resistor 401 and is covered together with the detection resistor 401 by the piezoelectric element 70. By providing a layer with low thermal conductivity on the surface of the detection resistor 401 opposite the surface facing the pressure chamber substrate 10, it is possible to prevent heat transferred from the ink in the pressure chamber 12 to the detection resistor 401 from being dissipated from the surface opposite the surface facing the pressure chamber substrate 10. The low thermal conductive layer 402 preferably has a thickness of 15 nanometers or more. The thicker the low thermal conductive layer 402, the more reliably it suppresses heat dissipation from the detection resistor 401. Note that the low thermal conductive layer 402 does not necessarily need to abut against the detection resistor 401. For example, an adhesive layer such as iridium (Ir) may be disposed between the detection resistor 401 and the low thermal conductive layer 402 to improve adhesion between the detection resistor 401 and the low thermal conductive layer 402.

[0060] 8, the low thermal conductive layer 402 is laminated on top of the detection resistor 401. From the viewpoint of facilitating electrical connection between the measurement lead electrode 93 and the detection resistor 401 via the contact hole 93H, the low thermal conductive layer 402 is preferably made of a conductive material such as a metal.

[0061] The structure and function of the low thermal conductive layer 402 will be described in detail with reference to FIGS. 9 and 10. FIG. 9 is an explanatory diagram showing an example of a material that can be used for the low thermal conductive layer 402. FIG. 9 shows a graph with thermal conductivity [W / (m·K)] on the horizontal axis and specific heat [J / (g·K)] on the vertical axis, plotting the results of each material using known physical properties. As shown in FIG. 9, the thermal conductivity [W / (m·K)] of each material is, for example, 17 for Ti, 13.4 for Ni and Cr, 56 for Ta, 58 for Nb, 70 for Pt, 147 for Ir, 236 for Al, and 295 for Au. The values ​​are also 0.03 for air, 1.38 for SiO2, 3 for ZrO2, 200 for SiC, and 150 for SiN. The specific heat [J / (g·K)] of each material is, for example, 0.52 for Ti, 0.5 for Ni and Cr, 0.14 for Ta, 0.27 for Nb, 0.13 for Pt, 0.13 for Ir, 0.13 for Al, 0.9 for Au, 1.03 for air, 0.77 for SiO2, 0.47 for ZrO2, 0.66 for SiC, and 0.68 for SiN.

[0062] From the viewpoint of suppressing heat radiation from the detection resistor 401, it is preferable that a material with low thermal conductivity is used for the low thermal conductive layer 402. For example, it has been experimentally confirmed that in temperature detection using the detection resistor 401, high measurement accuracy can be obtained when the low thermal conductive layer 402 has a thermal conductivity of 130 [W / (m·K)] or less. For this reason, it is preferable that the low thermal conductive layer 402 be made of any of SiO2, ZrO2, Ti, Ni, Cr, Ta, Nb, and Pt.

[0063] In this embodiment, the thermal conductivity of Pt used as the detection resistor 401 is 70. The thermal conductivity of the low thermal conductive layer 402 is preferably at least lower than that of the detection resistor 401, from the viewpoint of suppressing heat dissipation from the detection resistor 401. Furthermore, from the viewpoint of suppressing heat transfer from the low thermal conductive layer 402 to the detection resistor 401, the low thermal conductive layer 402 is preferably made of a material with a higher specific heat. Furthermore, the specific heat of the low thermal conductive layer 402 is preferably higher than that of the detection resistor 401. For these reasons, the low thermal conductive layer 402 is preferably made of any of Ti, Ni, Cr, Ta, and Nb. In this embodiment, the low thermal conductive layer 402 is made of Ti. Forming a Ti layer on the detection resistor 401 allows the low thermal conductive layer 402 to function as a seed layer or an orientation control layer for the piezoelectric element 70 on the low thermal conductive layer 402.

[0064] Fig. 10 is an explanatory diagram showing the cross-sectional structure near the detection resistor 401 and the low thermal conductive layer 402. Fig. 10 schematically shows the positional relationship of each layer in the stacking direction from the communicating plate 15 to the low thermal conductive layer 402. Note that Fig. 10 and Figs. 11 and 12, which will be described later, are conceptual diagrams and do not accurately show the thickness of each part.

[0065] 10 conceptually shows the path of heat dissipation from the ink in the pressure chamber 12. As shown by the arrow TD, the heat of the ink in the pressure chamber 12 is transferred to the detection resistor 401 via the diaphragm 50. The heat transferred to the detection resistor 401 is not easily transferred to the low thermal conductive layer 402, which has low thermal conductivity, but is easily transferred within the detection resistor 401, thereby improving the accuracy of temperature detection by the detection resistor 401.

[0066] As described above, the liquid ejection head 510 of this embodiment comprises a pressure chamber substrate 10 in which a plurality of pressure chambers 12 are provided, a first electrode 60 as an individual electrode provided individually for each of the plurality of pressure chambers 12, a second electrode 80 as a common electrode provided in common to each of the plurality of pressure chambers 12, a piezoelectric element 70 provided between the first electrode 60 and the second electrode 80 and for applying pressure to the ink in the pressure chambers 12, an individual lead electrode 91 and a common lead electrode 92 electrically connected to the first electrode 60 and the second electrode 80 and serving as drive wiring for applying a voltage to drive the piezoelectric element 70, a detection resistor 401 formed from the same material as any of the first electrode 60, the second electrode 80, the individual lead electrode 91, and the common lead electrode 92 and for detecting the temperature of the liquid in the pressure chamber 12, and a low thermal conductive layer 402 provided on the surface of the detection resistor 401 opposite to the surface facing the pressure chamber substrate 10 and serving as a first layer having a lower thermal conductivity than the detection resistor 401. By providing a low thermal conductivity layer 402 on the surface of the detection resistor 401 opposite to the surface facing the pressure chamber substrate 10, it is possible to reduce or prevent the heat transferred from the ink in the pressure chamber 12 to the detection resistor 401 from being dissipated from the detection resistor 401.

[0067] According to the liquid ejection head 510 of this embodiment, the detection resistor 401 is made of the same material as the first electrode 60. Therefore, the detection resistor 401 can be formed together with the first electrode 60 in the process of forming the first electrode 60. As a result, the manufacturing process can be simplified and productivity can be improved compared to when the detection resistor 401 is formed separately from the first electrode 60.

[0068] In the liquid ejection head 510 of this embodiment, the detection resistor 401 is made of Pt. By using a material whose electrical resistance changes greatly with temperature and which is highly stable and accurate for the detection resistor 401, the accuracy of temperature detection by the detection resistor 401 can be improved.

[0069] According to the liquid ejection head 510 of this embodiment, the low thermal conductive layer 402 as the first layer has a larger specific heat than the detecting resistor 401. Therefore, it is possible to reduce or suppress heat transfer from the low thermal conductive layer 402 to the detecting resistor 401, and it is possible to improve the accuracy of temperature detection by the detecting resistor 401.

[0070] According to the liquid ejection head 510 of this embodiment, the low thermal conductive layer 402 as the first layer is formed of metal. For example, an electrode located above the detection resistor 401, such as the measurement lead electrode 93, can be electrically connected to the detection resistor 401 via the low thermal conductive layer 402. Therefore, while providing the low thermal conductive layer 402, it is possible to easily electrically connect the relay substrate 120 and the detection resistor 401.

[0071] According to the liquid ejection head 510 of this embodiment, the low thermal conductive layer 402 is made of any one of Ti, Ni, Cr, Ta, and Nb. By using a metal material that has a lower thermal conductivity and a higher specific heat than Pt or the like used for the detection resistor 401, it is possible to form a low thermal conductive layer 402 that is suitable for temperature detection by the detection resistor 401.

[0072] According to the liquid ejection head 510 of this embodiment, the thermal conductivity of the low thermal conductive layer 402 is 130 [W / (m·K)] or less. Therefore, it is possible to form a low thermal conductive layer 402 that is suitable for temperature detection by the detection resistor 401.

[0073] The liquid ejection head 510 of this embodiment includes an insulator film 56 as a second insulating layer provided on the surface of the detection resistor 401 facing the pressure chamber substrate 10. By forming the detection resistor 401 on the second insulating layer, the detection accuracy of the electrical resistance value of the detection resistor 401 by the temperature acquisition unit 400 is improved, and the temperature detection accuracy can be improved.

[0074] According to the liquid ejection head 510 of this embodiment, the second layer is made of ZrO2. By forming the detection resistor 401 on the insulator film 56, the detection accuracy of the electrical resistance value of the detection resistor 401 by the temperature acquisition unit 400 is improved, and the temperature detection accuracy can be improved.

[0075] B. Second embodiment: 11 is a cross-sectional view showing the structure near the detection resistor 401 of a liquid ejection head 510 according to a second embodiment of the present disclosure. The liquid ejection head 510 of the second embodiment differs from the liquid ejection head 510 of the first embodiment in that the detection resistor 401 is layered on top of a high thermal conductivity layer 403 that has a higher thermal conductivity than the detection resistor 401, but other configurations are the same as those of the liquid ejection head 510 of the first embodiment.

[0076] 11, the detection resistor 401 is provided with a high thermal conductivity layer 403 in contact with the surface of the detection resistor 401 facing the pressure chamber substrate 10. In other words, the high thermal conductivity layer 403 is disposed between the detection resistor 401 and the insulating film 56 serving as the second layer. The layer disposed between the detection resistor 401 and the second layer and having a higher thermal conductivity than the detection resistor 401 is also referred to as the "third layer."

[0077] From the viewpoint of smoothly transferring heat from the ink in the pressure chamber 12 to the detection resistor 401, it is preferable that the thermal conductivity of the third layer is at least higher than that of the detection resistor 401. Therefore, as shown in FIG. 9, the high thermal conductivity layer 403 is preferably formed of, for example, Ir, Al, or Au. Furthermore, it is preferable that the high thermal conductivity layer 403 is made of a material having a lower specific heat than the detection resistor 401. Therefore, it is more preferable that the high thermal conductivity layer 403 is made of Ir or Au. It is preferable that the third layer has characteristics other than high thermal conductivity. In this embodiment, from the viewpoint of further improving adhesion between the insulator film 56 and the detection resistor 401, the high thermal conductivity layer 403 is made of Au.

[0078] The thickness of the high thermal conductivity layer 403 is preferably as thin as possible from the viewpoint of smoothly transferring heat from the ink in the pressure chamber 12 to the detection resistor 401. The thickness of the high thermal conductivity layer 403 is preferably at least thinner than the thickness of the detection resistor 401, and is more preferably thinner than the low thermal conductivity layer 402. The high thermal conductivity layer 403 is preferably less than 15 nanometers, for example. The high thermal conductivity layer 403 does not necessarily need to abut against the detection resistor 401, and for example, an adhesive layer made of, for example, Ti may be provided between the detection resistor 401 and the high thermal conductivity layer 403.

[0079] According to the liquid ejection head 510 of this embodiment, a high thermal conductivity layer 403 serving as a third layer having a higher thermal conductivity than the detection resistor 401 is provided between the detection resistor 401 and the insulating film 56 serving as the second layer. Therefore, the heat of the ink in the pressure chamber 12 can be smoothly transferred to the detection resistor 401 via the third layer.

[0080] According to the liquid ejection head 510 of this embodiment, the high thermal conductivity layer 403 is made of Au, which further improves the adhesion between the insulating film 56 as the second layer and the detection resistor 401.

[0081] According to the liquid ejection head 510 of this embodiment, the thickness of the high thermal conductive layer 403 is thinner than the thickness of the low thermal conductive layer 402. Therefore, heat radiation from the detection resistor 401 can be suppressed, and heat from the ink in the pressure chamber 12 can be smoothly transferred to the detection resistor 401 via the third layer.

[0082] According to the liquid ejection head 510 of this embodiment, the thickness of the low thermal conductive layer 402 is 15 nanometers or more. Therefore, heat from the ink in the pressure chamber 12 can be smoothly transferred to the detection resistor 401 via the third layer, while heat radiation from the detection resistor 401 can be suppressed.

[0083] C. Third embodiment: 12 is a cross-sectional view showing the structure near the detection resistor 401 of a liquid ejection head 510 according to a third embodiment of the present disclosure. The liquid ejection head 510 of the third embodiment differs from the liquid ejection head 510 of the first embodiment in that it includes a high thermal conductivity layer 403c as a third layer, but other configurations are similar to those of the liquid ejection head 510 of the first embodiment. The high thermal conductivity layer 403c differs from the high thermal conductivity layer 403 shown in the second embodiment in that it has a different cross-sectional shape, but other configurations are similar to those of the high thermal conductivity layer 403 of the second embodiment.

[0084] 12, the high thermal conductivity layer 403c has an uneven shape on the surface facing the detection resistor 401. The depth from the surface to the bottom of the uneven shape can be, for example, about 1 to 2 nanometers. The uneven shape can be formed, for example, by performing dry etching such as ion milling on the high thermal conductivity layer 403c.

[0085] By bringing the high thermal conductivity layer 403c and the detection resistor 401 into contact with each other via the uneven surface, the contact area between the high thermal conductivity layer 403c and the detection resistor 401 can be increased and heat can be transferred more smoothly from the high thermal conductivity layer 403c to the detection resistor 401, compared to when the high thermal conductivity layer 403c does not have an uneven shape. In addition, the adhesion between the detection resistor 401 and the insulator film 56 can be further improved.

[0086] D. Other Embodiments: (D1) In the first embodiment described above, an example was shown in which the detection resistor 401 is formed on the insulator film 56 serving as the second layer. However, an insulating layer other than the insulator film 56 may be provided as the second layer on the surface of the detection resistor 401 facing the pressure chamber substrate 10. FIG. 13 is a cross-sectional view showing the structure in the vicinity of the detection resistor 401 of a liquid ejection head 510 according to another embodiment of the present disclosure. As shown in FIG. 13, the detection resistor 401 may be formed on an insulating layer 52 that is different from the insulator film 56 and the elastic film 55. The insulating layer 52 may be formed of, for example, silicon, silicon nitride, or the like. Note that the detection resistor 401 may be provided so as to face a portion of the pressure chamber substrate 10 other than the ink flow path, such as the pressure chamber 12, as shown in FIG.

[0087] (D2) In each of the above embodiments, the detection resistor 401 is made of platinum (Pt), the same material as the first electrode 60. However, the detection resistor 401 is not limited to being made of an individual electrode, and may be made of the same material as the common electrode or the drive wiring. For example, the detection resistor 401 may be made of the same material as the second electrode 80, which is a common electrode. According to the liquid ejection head 510 of this embodiment, for example, the detection resistor 401 can be formed in the process of forming the second electrode 80, thereby simplifying the manufacturing process and reducing costs. Furthermore, the detection resistor 401 may be made of the same material as the individual lead electrode 91 and the common lead electrode 92, which are the drive wiring. According to the liquid ejection head 510 of this embodiment, for example, the detection resistor 401 can be formed in the process of forming the individual lead electrode 91 and the common lead electrode 92, thereby simplifying the manufacturing process and reducing costs.

[0088] (D3) In the above embodiments, an example was shown in which the second electrode 80 serving as a common electrode is provided on the upper part of the piezoelectric body 70, and the first electrode 60 serving as an individual electrode is provided on the lower part of the piezoelectric body 70. In contrast to this, the second electrode serving as a common electrode may be provided on the lower part of the piezoelectric body 70, and the first electrode 60 serving as an individual electrode may be provided on the upper part of the piezoelectric body 70.

[0089] E. Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0090] (1) According to one aspect of the present disclosure, there is provided a liquid ejection head comprising: a pressure chamber substrate having a plurality of pressure chambers; individual electrodes provided for the plurality of pressure chambers; a common electrode provided for the plurality of pressure chambers; a piezoelectric element provided between the individual electrodes and the common electrode for applying pressure to the liquid in the pressure chamber; drive wiring electrically connected to the individual electrodes and the common electrode for applying a voltage to drive the piezoelectric element; a detection resistor formed of the same material as any of the individual electrodes, the common electrode, and the drive wiring for detecting the temperature of the liquid in the pressure chamber; and a first layer provided on a surface of the detection resistor opposite to a surface facing the pressure chamber substrate, the first layer having a lower thermal conductivity than the detection resistor. According to this aspect of the liquid ejection head, a low thermal conductive layer is provided on a surface of the detection resistor opposite to a surface facing the pressure chamber substrate, thereby reducing or preventing heat transferred from the liquid in the pressure chamber to the detection resistor from being dissipated from the detection resistor.

[0091] (2) In the liquid ejection head of the above aspect, the detection resistor may be formed of the same material as the individual electrodes. According to this aspect of the liquid ejection head, the detection resistor can be formed together with the individual electrodes in the process of forming the individual electrodes.

[0092] (3) In the liquid ejection head of the above aspect, the detection resistor may be made of Pt. With this liquid ejection head, the detection resistor is made of a material that exhibits a large change in electrical resistance with temperature and is highly stable and accurate, thereby improving the accuracy of temperature detection by the detection resistor.

[0093] (4) In the liquid ejection head of the above aspect, the common electrode may be provided above the piezoelectric body, and the individual electrodes may be provided below the piezoelectric body.

[0094] (5) In the liquid ejection head of the above aspect, the first layer may further have a larger specific heat than the detection resistor. With this liquid ejection head, it is possible to reduce or suppress heat transfer from the first layer to the detection resistor, thereby improving the accuracy of temperature detection by the detection resistor.

[0095] (6) In the liquid ejection head of the above aspect, the first layer may be formed of metal. According to the liquid ejection head of this aspect, the electrode located above the detection resistor can be electrically connected to the detection resistor via the first layer.

[0096] (7) In the liquid ejection head of the above aspect, the first layer may be formed of any one of Ti, Ni, Cr, Ta, and Nb. According to the liquid ejection head of this aspect, by using a metal material with low thermal conductivity and high specific heat, it is possible to form the first layer suitable for temperature detection by the detection resistor.

[0097] (8) In the liquid ejection head of the above aspect, the thermal conductivity of the first layer may be 130 [W / (m·K)] or less. According to the liquid ejection head of this aspect, it is possible to form a first layer that is suitable for temperature detection by the detection resistor.

[0098] (9) In the liquid ejection head of the above aspect, the thickness of the first layer may be 15 nanometers or more. With this liquid ejection head, it is possible to more reliably reduce or prevent heat from being dissipated from the liquid in the pressure chamber through the detection resistor.

[0099] (10) The liquid ejection head of the above aspect may further include a second insulating layer provided on the surface of the detection resistor facing the pressure chamber substrate. According to this aspect of the liquid ejection head, the detection resistor is formed on the second insulating layer, thereby improving the accuracy of detecting the electrical resistance value of the detection resistor and improving the accuracy of detecting temperature.

[0100] (11) In the liquid ejection head of the above aspect, the second layer may be made of ZrO2.

[0101] (12) In the liquid ejection head of the above aspect, a third layer having a higher thermal conductivity than the detection resistor may be provided between the detection resistor and the second layer. With this liquid ejection head, heat from the liquid in the pressure chamber can be smoothly transferred to the detection resistor via the third layer.

[0102] (13) In the liquid ejection head of the above aspect, the third layer may be made of Au. According to the liquid ejection head of this aspect, it is possible to further improve the adhesion between the second layer and the detection resistor.

[0103] (14) In the liquid ejection head of the above aspect, the third layer may contact the detecting resistor via a surface having projections and recesses. This liquid ejection head increases the contact area between the third layer and the detecting resistor, thereby enabling smoother heat transfer from the third layer to the detecting resistor.

[0104] (15) In the liquid ejection head of the above aspect, the thickness of the third layer may be thinner than the thickness of the first layer. With this liquid ejection head, heat radiation from the detection resistor can be suppressed, and heat from the liquid in the pressure chamber can be smoothly transferred to the detection resistor via the third layer.

[0105] (16) According to another aspect of the present disclosure, there is provided a liquid ejection device including the liquid ejection head of the above aspect and a control unit that controls the ejection operation of the liquid ejection head.

[0106] The present disclosure can also be realized in various forms other than liquid ejection devices and liquid ejection heads, for example, in the form of a method for manufacturing a liquid ejection head, a method for manufacturing a liquid ejection device, etc.

[0107] The present disclosure is not limited to inkjet systems, but can also be applied to any liquid ejection device that ejects liquid other than ink and the liquid ejection heads used in such liquid ejection devices. For example, the present disclosure can be applied to various liquid ejection devices and their liquid ejection heads, such as those listed below. (1) Image recording devices such as facsimile machines. (2) A color material ejection device used in the manufacture of color filters for image display devices such as liquid crystal displays. (3) Electrode material ejection equipment used to form electrodes for organic EL (Electro Luminescence) displays, surface-emitting displays (Field Emission Displays, FEDs), etc. (4) A liquid ejection device that ejects a liquid containing a bioorganic substance used in biochip manufacturing. (5) A sample dispensing device as a precision pipette. (6) Lubricating oil discharge device. (7) A resin liquid ejection device. (8) A liquid ejection device that ejects lubricating oil precisely onto precision machinery such as watches and cameras. (9) A liquid ejection device that ejects a transparent resin liquid, such as an ultraviolet curable resin liquid, onto a substrate to form minute hemispherical lenses (optical lenses) used in optical communication elements, etc. (10) A liquid ejection device that ejects an acidic or alkaline etching liquid for etching a substrate or the like. (11) A liquid ejection device having a liquid consuming head that ejects any other minute amount of liquid droplets.

[0108] A "liquid" can be any material that can be consumed by a liquid ejection device. For example, a "liquid" can be any material in a liquid phase, and includes materials with high or low viscosity, as well as liquid materials such as sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, and liquid metals (metal melts). Furthermore, not only liquids as a state of matter, but also particles of functional materials made of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent are also included in the term "liquid." Representative examples of liquids include the following: (1) Adhesive base and hardener (2) Base paints and thinners, clear paints and thinners (3) The main solvent and dilution solvent containing cells in the cell-based ink (4) Metallic leaf pigment dispersion and dilution solvent for ink (metallic ink) that expresses a metallic luster (5) Gasoline, diesel and biofuels for vehicles (6) Main ingredients and protective ingredients of medicines (7) Phosphors and encapsulants for light-emitting diodes (LEDs) [Explanation of symbols]

[0109] 10...pressure chamber substrate, 11...partition wall, 12...pressure chamber, 13...throttle portion, 14...pressure chamber supply path, 15...communication plate, 16...nozzle communication path, 17...first manifold portion, 18...second manifold portion, 19...supply communication path, 20...nozzle plate, 21...nozzle, 30...protective substrate, 30T...lid portion, 30W...wall portion, 31...holding portion, 32...through hole, 40...case member, 41...accommodating portion, 42...third manifold conductor portion, 43...connection port, 44...supply port, 45...compliance substrate, 46...sealing film, 47...fixed substrate, 48...opening, 49...compliance portion, 50...diaphragm, 52...insulating layer, 55...elastic film, 56...insulating film, 60...first electrode, 60b...end portion, 70...piezoelectric body, 70a, 70b...end portion, 80...second electrode, 80b...end portion, 85...wiring portion, 91...individual lead electrode, 92...common lead electrode, 92a, 92b...extension portion, 93, 93a, 93b...measurement lead electrode, 93H...contact hole, 96...wiring portion, 100...manifold, 120...relay board, 121...integrated circuit, 300...piezoelectric element, 400...temperature acquisition portion, 401...detection resistor, 402...low thermal conductivity layer, 403, 403c...high thermal conductivity layer, 430...current application circuit, 440...voltage detection circuit, 450...temperature calculation portion, 460...storage Storage unit, 500...liquid ejection device, 510...liquid ejection head, 550...ink tank, 552...tube, 560...transport mechanism, 562...transport roller, 564...transport rod, 566...transport motor, 570...movement mechanism, 572...carriage, 574...transport belt, 576...movement motor, 577...pulley, 580...control unit, L1...first pressure chamber row, L2...second pressure chamber row, P...printing paper

Claims

1. A liquid ejection head, a pressure chamber substrate provided with a plurality of pressure chambers; individual electrodes provided individually for the plurality of pressure chambers; a common electrode provided in common to the plurality of pressure chambers; a pressure sensor provided between the individual electrode and the common electrode for applying pressure to the liquid in the pressure chamber; a piezoelectric body for The individual electrodes and the common electrode are electrically connected to each other, and the piezoelectric element is driven by the individual electrodes and the common electrode. drive wiring for applying pressure; The individual electrodes, the common electrodes, and the drive wirings are formed of the same material, and the pressure a sensing resistor for sensing the temperature of the liquid in the chamber; The detecting resistor is provided on a surface opposite to a surface facing the pressure chamber substrate, a first layer having a thermal conductivity lower than that of the resistor and formed of a metal; Liquid ejection head.

2. 2. The method according to claim 1, wherein the first layer is made of any one of Ti, Ni, Cr, Ta, and Nb. The liquid ejection head according to claim 1.

3. A liquid ejection head, a pressure chamber substrate provided with a plurality of pressure chambers; individual electrodes provided individually for the plurality of pressure chambers; a common electrode provided in common to the plurality of pressure chambers; a pressure sensor provided between the individual electrode and the common electrode for applying pressure to the liquid in the pressure chamber; a piezoelectric body for The individual electrodes and the common electrode are electrically connected to each other, and the piezoelectric element is driven by the individual electrodes and the common electrode. drive wiring for applying pressure; The individual electrodes, the common electrodes, and the drive wirings are formed of the same material, and the pressure a sensing resistor for sensing the temperature of the liquid in the chamber; The detecting resistor is provided on a surface opposite to a surface facing the pressure chamber substrate, a first layer having a lower thermal conductivity than the resistor; a second layer having insulating properties, the second layer being provided on a surface of the detection resistor facing the pressure chamber substrate; and, Liquid ejection head.

4. 4. The liquid ejection head according to claim 3, wherein the second layer is made of ZrO2.

5. Between the detection resistor and the second layer, a layer having a higher thermal conductivity than the detection resistor is provided. The liquid ejection head according to claim 3 or 4, further comprising a third layer.

6. The liquid ejection head according to claim 5 , wherein the third layer is made of Au.

7. The third layer abuts against the detection resistor via a surface having projections and recesses.

7. The liquid ejection head according to claim 6.

8. Any of claims 5 to 7, wherein the thickness of the third layer is thinner than the thickness of the first layer.

1. The liquid ejection head according to claim 1 .

9. 10. The detecting resistor is formed of the same material as the individual electrodes.

10. The liquid ejection head according to claim 1,

10. 10. The detecting resistor according to claim 1, wherein the detecting resistor is made of Pt. The liquid ejection head according to claim 1.

11. 11. The liquid ejection head according to claim 1, the common electrode is provided on the upper part of the piezoelectric body, The individual electrodes are provided below the piezoelectric bodies. Liquid ejection head.

12. 12. The method according to claim 1, wherein the first layer further has a specific heat greater than that of the detection resistor.

10. The liquid ejection head according to claim 1, wherein the liquid ejection head is a liquid ejection head having a diameter of 100 mm or less.

13. The thermal conductivity of the first layer is 130 [W / (m·K)] or less.

13. A liquid ejection head according to any one of claims 11 to 12.

14. Any of claims 1 to 13, wherein the thickness of the first layer is 15 nanometers or more.

2. The liquid ejection head according to claim 1,

15. A liquid ejection head according to any one of claims 1 to 14, a control unit that controls the ejection operation of the liquid ejection head, Liquid discharge device.

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