Liquid ejection head and liquid ejection device

Abstract

To provide a liquid discharge head that can suppress heat of a detection resister from being radiated so as to enhance accuracy in detection of a temperature by the detection register.SOLUTION: A liquid discharge head comprises: a pressure chamber substrate provided with a plurality of pressure chambers; an individual electrode; a common electrode; a piezoelectric body provided between the individual electrode and the common electrode to apply pressure to liquid in the pressure chambers; drive wiring that applies a voltage so as to drive the piezoelectric body; a detection resistor 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 sealing substrate that has a wall portion and a ceiling portion, and protects the piezoelectric body by the wall portion and the ceiling portion. The detection resistor is provided to have a part overlapping the wall portion which is shorter than a part not overlapping the wall portion when viewed along a lamination direction of the piezoelectric body, the individual electrode and the common electrode.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. The liquid ejection head includes 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 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 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 sealing substrate having wall portions and a ceiling portion for protecting the piezoelectric element. When viewed along the stacking direction of the piezoelectric element, the individual electrodes, and the common electrode, the detection resistor is provided so that the portion overlapping with the wall portion is shorter than the portion not overlapping with the wall portion.

[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 showing 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]10 is an explanatory diagram showing the positional relationship between a detection resistor and a sealing substrate in a plan view. FIG. [Figure 10] FIG. 10 is an explanatory diagram showing the configuration of a liquid ejection head according to a second embodiment in a plan view. [Figure 11] FIG. 10 is an explanatory diagram showing the configuration of a liquid ejection head according to a third embodiment in a plan view. [Figure 12] FIG. 10 is an explanatory diagram showing a cross-sectional view of the configuration of a liquid ejection head according to a fourth embodiment. 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 as "+" and a negative direction indicated as "-." 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 ink within the pressure chamber. 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 of the pressure chamber substrate 10 and its surroundings in the liquid ejection head 510. In FIG. 4, the sealing 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 sealing substrate 30, a case member 40, a vibration plate 50, and an intermediate 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 sealing 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, etc. 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.” In a plan view, 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 the present disclosure, “plan view” refers to a state in which an object is viewed along the stacking direction. The shape of the pressure chambers 12 is not limited to a rectangular shape, and may be a parallelogram, a polygon, a circle, an oval, etc. An oval shape refers to a shape based on a rectangular shape with semicircular ends at both longitudinal ends, and includes a rounded rectangle, an ellipse, an egg shape, etc.

[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. A direction perpendicular to both the arrangement direction and the stacking 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 plurality of pressure chambers 12 belonging to the first pressure chamber row L1 and the plurality of 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.

[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 is a flow path whose inner wall protrudes further than the pressure chamber 12 and the pressure chamber supply path 14 and is formed narrower 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. With the liquid ejection head 510 configured in this manner, it is possible to reduce or prevent ink from flowing back into the pressure chamber supply path 14 in the pressure chamber 12 even when pressure is applied to the pressure chamber 12 by the piezoelectric element 300 during ink ejection. There are multiple supply communication passages 19, which are arranged in the Y-axis direction, i.e., the arrangement direction, and each is provided individually 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 sealing substrate 30, which has approximately 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 39 (described later). The sealing substrate 30 includes a ceiling portion 30T, a wall portion 30W, a holding portion 31, and a through-hole 32. The holding portion 31 is a concave space defined by the ceiling portion 30T and the wall portion 30W, and protects the active portions of the piezoelectric elements 300. The holding portions 31 of the sealing substrate 30 are provided for each column 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 sealing substrate 30 along the Z-axis direction.

[0033] 5, a case member 40 is fixed on the sealing 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 to cover the sealing 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 sealing 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 sealing substrate 30, and an intermediate 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 portion of the piezoelectric element 300 where piezoelectric strain occurs in the piezoelectric body 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is also called an active portion. The active portion is a portion of the piezoelectric element 300 where the piezoelectric body 70 is sandwiched between the first electrode 60 and the second electrode 80.

[0040] A driving 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 active part of 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 part of the piezoelectric element 300 that actually displaces in the Z-axis direction when it is driven is also called the flexible part. The part of the piezoelectric element 300 that faces the pressure chamber 12 in the Z-axis direction is the flexible part. 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.

[0041] The first electrodes 60 are individual electrodes provided for the multiple pressure chambers 12. As shown in FIG. 7, the first electrodes 60 are lower electrodes 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 thickness of the first electrodes 60 is, 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.

[0042] 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, the end 70a of the piezoelectric body 70 in the +X direction is covered by a wiring portion 96 that is formed at the same time as the individual lead electrodes 91. An adhesive 39 is disposed on the upper part of the wiring portion 96 to bond the wall portion 30W of the sealing substrate 30. The wiring portion 96 may be omitted.

[0043] The thickness of the piezoelectric body 70 is, for example, approximately 1000 to 4000 nanometers. Examples of the piezoelectric body 70 include a perovskite-structured crystalline film made of a ferroelectric ceramic material exhibiting electromechanical transduction, which is formed on the first electrode 60, known as a perovskite crystal. Examples of materials that can be used for the piezoelectric body 70 include ferroelectric piezoelectric materials such as lead zirconate titanate (PZT), and materials to which metal oxides such as niobium oxide, nickel oxide, or magnesium oxide are added. Specifically, examples that can be used include lead titanate (PbTiO), lead zirconate titanate (Pb(Zr,Ti)O), lead zirconate (PbZrO), lead lanthanum titanate ((Pb,La),TiO), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O), and magnesium niobate lead zirconium titanate (Pb(Zr,Ti)(Mg,Nb)O). In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric body 70.

[0044] 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)).

[0045] 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 an upper electrode 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, above the piezoelectric body 70. The material of the second electrode 80 is not particularly limited, but, like 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.

[0046] As shown in FIG. 7 , a wiring portion 85 is provided further toward the −X direction than the −X direction end portion 80b of the second electrode 80. The wiring portion 85 is formed 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 the wiring portion 85 and the end portion 80b of the second electrode 80. The −X direction end portion 60b of the first electrode 60 extends further to the outside than the end portion 70b of the piezoelectric body 70. A plurality of wiring portions 85 are provided for each piezoelectric element 300, and 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 separate from the second electrode 80.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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 in the -X direction onto the diaphragm 50. The individual lead electrode 91 is electrically connected to the end 60b of the first electrode 60 in the -X direction, which is drawn out further to the outside than the end 70b of the piezoelectric body 70. The wiring portion 85 may be omitted, and the individual lead electrode 91 may be directly connected to the end 60b of the first electrode 60.

[0051] 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, one end of each of the individual lead electrodes 91 and the common lead electrode 92 extends so as to be exposed in a through hole 32 formed in the sealing substrate 30, and is electrically connected to the relay substrate 120 within the through hole 32.

[0052] 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.

[0053] 4 and 6 show the measurement lead electrode 93. The measurement lead electrode 93 is electrically connected to the detection resistor 401. In this embodiment, the measurement lead electrode 93 is formed in the same layer as the individual lead electrodes 91 and the common lead electrode 92, and is formed so as to be electrically discontinuous with each other. The detection resistor 401 is electrically connected to the relay board 120 by the measurement lead electrode 93, which enables the temperature calculation unit 450 to detect the electrical resistance value of the detection resistor 401.

[0054] The measurement lead electrode 93 is 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, the measurement lead electrode 93 is made of gold (Au), which has a lower electrical resistance than platinum (Pt) used as the detection resistor 401 (described later). The measurement lead electrode 93 is made of the same material as the individual lead electrode 91 and the common lead electrode 92. The measurement lead electrode 93 may be made of any material other than gold (Au), or may be made of a different material from the individual lead electrode 91 and the common lead electrode 92.

[0055] 8, the measurement lead electrode 93 includes wiring portions 93a and 93b extending above the piezoelectric body 70, and a contact hole 93H provided in a through hole 70H that penetrates the piezoelectric body 70. The through hole 70H can be formed, for example, by ion milling when forming the piezoelectric body 70. The wiring portion 93a is electrically connected to the detection resistor 401 via the contact hole 93H. Although not shown, the wiring portion 93b is also electrically connected to the detection resistor 401 via the contact hole 93H. The contact hole 93H may be provided in only one of the wiring portions 93a and 93b. In addition, the contact hole 93H may be omitted. In this case, for example, the detection resistor 401 may be extended so that the detection resistor 401 is exposed from the end 70b of the piezoelectric body 70, and the wiring portions 93a, 93b may be electrically connected to the detection resistor 401 exposed from the end 70b.

[0056] 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 formed continuously so as to surround the periphery of the first pressure chamber row L1 and the second pressure chamber row L2 in a plan view. More specifically, the detection resistor 401 includes a first extension portion 401A electrically connected to the measurement lead electrode 93, which is the first wiring portion, a second extension portion 401B continuing from the first extension portion 401A, and a third extension portion 401C.

[0057] The first extension portion 401A extends along the X-axis direction, which is the intersecting direction, at a position on one side in the arrangement direction of the multiple pressure chambers 12, specifically on the -Y direction side. In this embodiment, the first extension portion 401A includes a first extension portion 401A1 connected to the wiring portion 93a and a first extension portion 401A2 electrically connected to the wiring portion 93b. The second extension portion 401B extends along the Y-axis direction, which is the arrangement direction. In this embodiment, the second extension portion 401B includes a second extension portion 401B1 continuous with the first extension portion 401A1 and a second extension portion 401B2 continuous with the first extension portion 401A2. The third extension portion 401C extends along the X-axis direction, which is the intersecting direction, at a position on the other side in the arrangement direction of the multiple pressure chambers 12, specifically on the +Y direction side. In this embodiment, the third extension portion 401C is formed continuously from the second extension portion 401B, and electrically connects the second extension portion 401B1 and the second extension portion 401B2.

[0058] As shown in FIGS. 6 and 7 as examples, the detection resistor 401 is arranged to pass near the ink flow path in the pressure chamber substrate 10. In this embodiment, the second extension portion 401B of the detection resistor 401 is arranged to pass on the -Z direction side of the vibration plate 50 with respect to the throttle portion 13 near each pressure chamber 12. For this reason, the second extension portion 401B can be considered to be a portion that contributes more to detecting the temperature of ink in the pressure chamber 12 than the first extension portion 401A and the third extension portion 401C. In the example of FIG. 4, the second extension portion 401B of the detection resistor 401 is formed in a so-called meandering pattern that moves back and forth multiple times along the arrangement direction. By configuring the second extension portion 401B, which contributes more to temperature detection, in this manner, the detection accuracy of the ink temperature in the pressure chamber 12 by the detection resistor 401 can be improved. However, the second extension portion 401B of the detection resistor 401 may be formed in a serpentine pattern that moves back and forth multiple times along the intersecting direction instead of the arrangement direction, or may be formed in any shape, such as a straight line, instead of the serpentine pattern.

[0059] 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.

[0060] 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. In this embodiment, the detection resistor 401 is formed together with the first electrode 60 in the process of forming the first electrode 60. That is, the detection resistor 401 is formed of platinum (Pt), which is the same material 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.

[0061] From the viewpoint of preventing a decrease in the accuracy of temperature detection, it is preferable to prevent heat radiation from the detection resistor 401. As shown in Fig. 7, in this embodiment, a low thermal conductive layer 402 is further laminated on top of 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 is a layer with lower thermal conductivity than the detection resistor 401.

[0062] As shown in FIG. 8 , the low thermal conductive layer 402 is preferably made of a conductive material such as metal to facilitate electrical connection between the measurement lead electrode 93 and the upper part of the detection resistor 401 via the contact hole 93H. By providing a low thermal conductivity layer on the surface of the detection resistor 401 opposite the surface facing the pressure chamber substrate 10, heat transferred from the ink in the pressure chamber 12 to the detection resistor 401 can be prevented from being dissipated from the surface opposite the surface facing the pressure chamber substrate 10. The low thermal conductive layer 402 is preferably as thick as possible to more reliably prevent heat dissipation from the detection resistor 401. The low thermal conductive layer 402 does not necessarily need to be in contact with 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. The low thermal conductive layer 402 can be omitted, and in the following description, unless otherwise specified, the configuration of the low thermal conductive layer 402 will be omitted.

[0063] The position of the detection resistor 401 will be described in detail with reference to FIG. 7 and FIG. 9. FIG. 7 conceptually illustrates an area AT above the detection resistor 401. The area AT is an area that can cover the detection resistor 401 and its vicinity. In this embodiment, the amount of material disposed in the area AT is reduced to prevent heat from being dissipated from the detection resistor 401 through the material disposed in the area AT. Specifically, the amount of the wiring portion 96, adhesive 39, and wall portion 30W of the sealing substrate 30 disposed in the area AT is set to only the overlapping portion 401T (described later), thereby reducing the amount of material disposed in the area AT. This makes it possible to prevent heat from being transferred from the detection resistor 401 to the wiring portion 96, adhesive 39, and wall portion 30W and dissipated.

[0064] FIG. 9 is an explanatory diagram showing the positional relationship between the detection resistor 401 and the sealing substrate 30 in a plan view. In FIG. 9, the wall portions 30W of the sealing substrate 30 are hatched to facilitate understanding of the technology. The portion surrounded by the wall portions 30W corresponds to the ceiling portion 30T of the sealing substrate 30. The overlapping portion 401T shown in FIG. 9 indicates the portion of the detection resistor 401 that overlaps with the wall portions 30W of the sealing substrate 30 in a plan view. The overlapping portion 401T is a part of the third extension portion 401C of the detection resistor 401. On the other hand, the overlapping portion 401T does not exist in the first extension portion 401A or the second extension portion 401B. In this embodiment, the detection resistor 401 is provided such that the overlapping portion between the detection resistor 401 and the wall portions 30W is shorter than the portion where the detection resistor 401 does not overlap with the wall portions 30W in a plan view.

[0065] In this embodiment, the detection resistor 401 is further provided such that the portion where the detection resistor 401 overlaps with the ceiling portion 30T is longer than the portion where the detection resistor 401 does not overlap with the ceiling portion 30T. That is, the detection resistor 401 is configured such that the portion disposed inside the wall portion 30W of the sealing substrate 30 is larger than the other portions. According to the liquid ejection head 510 configured in this manner, by increasing the portion of the detection resistor 401 covered by the sealing substrate 30, it is possible to prevent the detection resistor 401 from being exposed to the outside air, foreign matter, and the like. However, without being limited thereto, the detection resistor 401 may be configured such that the portion disposed outside the wall portion 30W of the sealing substrate 30 is larger than the other portions.

[0066] As shown in FIG. 7 , in this embodiment, the detection resistor 401 is provided in an exposed state in a groove 70G provided in the piezoelectric body 70. The groove 70G is not shown in FIGS. 4 , 6 , and 9 . The groove 70G is provided at a position corresponding to the arrangement positions of the second extension portion 401B and the third extension portion 401C of the detection resistor 401, but is not provided at a position corresponding to the arrangement position of the first extension portion 401A. According to the liquid ejection head 510 configured in this manner, by covering the detection resistor 401 with an air layer having low thermal conductivity, heat dissipation from the detection resistor 401 can be reduced or prevented. However, the groove 70G is not necessarily provided, and the detection resistor 401 may be arranged in a state where it is covered by the piezoelectric body 70, for example.

[0067] As described above, the liquid ejection head 510 of this embodiment includes the pressure chamber substrate 10 in which a plurality of pressure chambers 12 are provided, the first electrodes 60 as individual electrodes provided individually for the plurality of pressure chambers 12, the second electrode 80 as a common electrode provided in common to the plurality of pressure chambers 12, the piezoelectric bodies 70 provided between the individual electrodes and the common electrode for applying pressure to the liquid in the pressure chambers 12, the individual lead electrodes 91 and the common lead electrode 92 electrically connected to the individual electrodes and the common electrode as drive wiring for applying a voltage to drive the piezoelectric bodies 70, the detection resistors 401 for detecting the temperature of the ink in the pressure chambers 12, and the sealing substrate 30 having wall portions 30W and a ceiling portion 30T that protect the piezoelectric bodies 70. When viewed along the stacking direction of the piezoelectric bodies 70, the upper electrode, and the lower electrode, the detection resistors 401 are provided so that the portion overlapping with the wall portions 30W is shorter than the portion not overlapping with the wall portions 30W. According to the liquid ejection head 510 of this embodiment, it is possible to avoid arranging the wall portion 30W or the like above the detection resistor 401, and to prevent the heat of the detection resistor 401 from being dissipated through the wall portion 30W or the like. This improves the accuracy with which the detection resistor 401 detects the electrical resistance value, and thereby improves the accuracy with which the detection resistor 401 detects the temperature of the ink in the pressure chamber 12.

[0068] According to the liquid ejection head 510 of this embodiment, the detection resistor 401 is provided such that, when viewed along the stacking direction, the portion that overlaps with the ceiling portion 30T is longer than the portion that does not overlap with the ceiling portion 30T. According to the liquid ejection head 510 configured in this manner, by increasing the portion of the detection resistor 401 that is covered by the sealing substrate 30, it is possible to prevent the detection resistor 401 from being exposed to the outside air, foreign matter, and the like.

[0069] In the liquid ejection head 510 of this embodiment, the detection resistor 401 is formed from the same material as the individual electrodes. With this type of liquid ejection head 510, the detection resistor 401 can be formed in the same process as the individual electrodes, simplifying the manufacturing process and reducing costs.

[0070] In the liquid ejection head 510 of this embodiment, the detection resistor 401 is provided in an exposed state in a groove portion 70G provided in the piezoelectric body 70. According to the liquid ejection head 510 of this embodiment, by covering the detection resistor 401 with an air layer, it is possible to reduce or prevent heat radiation from the detection resistor 401.

[0071] According to the liquid ejection head 510 of this embodiment, when the direction in which the multiple pressure chambers 12 are arranged is defined as the arrangement direction and the direction perpendicular to both the arrangement direction and the stacking direction is defined as the intersecting direction, the detection resistor 401 is provided with a first extension portion 401A extending along the intersecting direction at a position on one side in the arrangement direction relative to the multiple pressure chambers 12, and a second extension portion 401B continuing from the first extension portion 401A and extending along the arrangement direction. By arranging the second extension portion 401B along the arrangement direction of the multiple pressure chambers 12, the detection resistor 401 can be arranged efficiently from the perspective of temperature detection of the multiple pressure chambers 12.

[0072] According to the liquid ejection head 510 of this embodiment, the detection resistor 401 further includes a third extending portion 401C extending along the intersecting direction at a position on the other side in the arrangement direction of the plurality of pressure chambers 12. By arranging the detection resistor 401 so as to surround the plurality of pressure chambers 12, the detection resistor 401 can be arranged efficiently.

[0073] The liquid ejection device 500 of this embodiment includes the above-described liquid ejection head 510 and a control unit 580 that controls the ejection operation of the liquid ejection head 510. Therefore, it is possible to provide a liquid ejection device 500 that can improve the accuracy with which the detection resistor 401 detects the electrical resistance value, and can improve the accuracy with which the detection resistor 401 detects the temperature of the ink in the pressure chamber 12.

[0074] B. Second embodiment: 10 is an explanatory diagram showing a plan view of the configuration of a liquid ejection head 510b according to a second embodiment of the present disclosure. As shown in Fig. 10, the liquid ejection head 510b according to the second embodiment differs from the liquid ejection head 510 according to the first embodiment in that the liquid ejection head 510b according to the second embodiment is configured such that there is no overlapping portion 401T of the detection resistor 401 that overlaps with the wall portion 30W of the sealing substrate 30. The other configurations are the same as those of the liquid ejection head 510 according to the first embodiment.

[0075] 10 , in a liquid ejection head 510b according to the second embodiment, the measurement lead electrode 93 is provided with wiring portions 93a1 and 93a2, which are configured similarly to the wiring portion 93a and are located on the −Y direction side of the pressure chamber substrate 10, and wiring portions 93b1 and 93b2, which are configured similarly to the wiring portion 93b and are located on the +Y direction side of the pressure chamber substrate 10. Instead of the detection resistor 401, the liquid ejection head 510b is provided with a detection resistor 401b1 for detecting the temperature of ink in the pressure chambers 12 included in the first pressure chamber array L1, and a detection resistor 401b2 for detecting the temperature of ink in the pressure chambers 12 included in the second pressure chamber array L2. The detection resistor 401b1 is electrically connected to the wiring portion 93a1 and the wiring portion 93b1, and is also electrically connected to the relay substrate 120. The detection resistor 401b2 is electrically connected to the wiring portion 93a2 and the wiring portion 93b2, and is electrically connected to the relay substrate 120. According to the liquid ejection head 510 configured in this manner, it is possible to individually detect the temperature of ink inside each of predetermined pressure chamber groups each having a plurality of pressure chambers 12, such as the first pressure chamber row L1 and the second pressure chamber row L2.

[0076] In this embodiment, the wiring portions 93a1, 93a2, 93b1, and 93b2 and the detection resistors 401b1 and 401b2 are electrically connected to each other at positions inside the wall portion 30W of the sealing substrate 30 in a plan view. The detection resistors 401b1 and 401b2 are configured so as not to have overlapping portions 401T that overlap with the wall portion 30W of the sealing substrate 30 in a plan view. That is, the detection resistors 401b1 and 401b2 are provided so as not to overlap with the wall portion 30W in a plan view. The detection resistors 401b1 and 401b2 are also provided so as not to overlap with the wall portion 30W in a plan view, and are provided so as to be inside the wall portion 30W of the sealing substrate 30 in a plan view, and overlap only with the ceiling portion 30T.

[0077] According to the liquid ejection head 510b of this embodiment, the detection resistors 401b1 and 401b2 are arranged so as not to overlap with the wall portion 30W in a plan view. This more reliably prevents the heat from the detection resistors 401b1 and 401b2 from being dissipated via the wall portion 30W or the like, and further improves the accuracy with which the detection resistors 401b1 and 401b2 detect the temperature of the ink in the pressure chamber 12.

[0078] According to the liquid ejection head 510b of this embodiment, the detection resistors 401b1 and 401b2 are provided so as to overlap only with the ceiling portion 30T in a plan view. According to the liquid ejection head 510 configured in this manner, by covering the entire detection resistors 401b1 and 401b2 with the sealing substrate 30, it is possible to more reliably prevent the detection resistors 401b1 and 401b2 from being exposed to the outside air, etc.

[0079] C. Third embodiment: 11 is an explanatory diagram showing, in plan view, the configuration of a liquid ejection head 510c according to a third embodiment of the present disclosure. As shown in FIG. 11, the liquid ejection head 510c according to the third embodiment differs from the liquid ejection head 510 according to the first embodiment in that, as in the second embodiment, the measurement lead electrode 93 includes wiring portions 93a1, 93a2, 93b1, and 93b2 instead of the wiring portions 93a and 93b, and in that the detection resistor 401 includes detection resistors 401b1 and 401b2 instead of the detection resistor 401. Another difference is that the overlapping portions 401T of the detection resistors 401b1 and 401b2, which are portions that overlap with the wall portion 30W of the sealing substrate 30, are positioned differently. The remaining configuration is the same as that of the liquid ejection head 510 according to the first embodiment.

[0080] As shown in FIG. 11, in this embodiment, the overlapping portion 401T is a part of the second extending portion 401B of the detection resistors 401b1 and 401b2. The overlapping portion 401T does not exist in the first extending portion 401A or the third extending portion 401C. Furthermore, the portions of the detection resistors 401b1 and 401b2 that overlap with the ceiling portion 30T are longer than the portions that do not overlap with the ceiling portion 30T. In this way, the overlapping portion 401T may exist in any part of the detection resistors 401b1 and 401b2. This configuration of the liquid ejection head 510c can also achieve the same effects as the first embodiment.

[0081] D. Fourth embodiment: 12 is an explanatory diagram showing a cross-sectional view of the configuration of a liquid ejection head 510d according to a fourth embodiment of the present disclosure. As shown in Fig. 12, the liquid ejection head 510d according to the fourth embodiment differs from the liquid ejection head 510 according to the first embodiment in that a detection resistor 401 is provided in a groove 70G provided in a piezoelectric body 70 and is covered with an insulating film 405. The other configuration is the same as that of the liquid ejection head 510 according to the first embodiment.

[0082] The insulator film 405 is formed on the upper portion of the detection resistor 401 provided in the groove 70G and covers the detection resistor 401. The insulator film 405 functions as a protective film that protects the detection resistor 401 from condensation, foreign matter, and the like. The insulator is used to prevent short-circuiting between the wiring of the detection resistor 401. The insulator film 405 can be formed using, for example, the same material as the adhesive 39. This configuration allows the insulator film 405 to be formed during the formation process of the adhesive 39, thereby simplifying the manufacturing process and reducing costs. Note that the insulator film 405 is not limited to the same material as the adhesive 39 and may be formed using other insulators such as silicon oxide or zirconium oxide. In cases where the detection resistor 401 is formed linearly and no short-circuiting of the detection resistor 401 occurs, a protective film using a conductor such as a metal may be formed instead of the insulator film 405.

[0083] In the liquid ejection head 510d of this embodiment, the detection resistor 401 is provided in a groove 70G provided in the piezoelectric body 70 and is covered with an insulating film 405. According to the liquid ejection head 510d of this embodiment, the heat of the detection resistor 401 is prevented from being dissipated to the wall 30W or the like, and the insulating film 405 can protect the detection resistor 401 from condensation and foreign matter.

[0084] E. Other Embodiments: (E1) In the first embodiment described above, an example was shown in which the second electrode 80 serving as a common electrode is provided above the piezoelectric body 70, and the first electrode 60 serving as an individual electrode is provided below the piezoelectric body 70. However, the common electrode may be a lower electrode provided below the piezoelectric body 70, and the individual electrodes may be upper electrodes provided above the piezoelectric body 70. In this case, it is preferable that the detection resistor 401 is formed using the same material as the lower electrode serving as a common electrode provided below the piezoelectric body 70. This allows the detection resistor 401 to be formed in the process of forming the common electrode, simplifying the manufacturing process and reducing costs.

[0085] (E2) In the first embodiment, the detection resistor 401 is made of platinum (Pt), the same material as the first electrode 60. However, the detection resistor 401 may be made of the same material as the individual electrode, the common electrode, or the drive wiring, not limited to the individual electrode. For example, the detection resistor 401 may be made of the same material as the second electrode 80, which is the 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.

[0086] (E3) In the first embodiment described above, the detection resistor 401 includes the first extension portion 401A electrically connected to the measurement lead electrode 93, which is the first wiring portion, the second extension portion 401B continuing from the first extension portion 401A, and the third extension portion 401C. Alternatively, the third extension portion 401C may be omitted, and only the first extension portion 401A and the second extension portion 401B may be provided. In this case, for example, the wiring portion 93b may be provided adjacent to the wiring portion 93a, and two first extension portions 401A may be provided: the first extension portion 401A connected to the wiring portion 93a, and the first extension portion 401A connected to the wiring portion 93b. The second extension portion 401B may be connected to the two first extension portions 401A and have a shape that makes a round trip along the arrangement direction.

[0087] (E4) In the above first embodiment, an example was shown in which the wiring portions 93a and 93b were arranged on the −Y direction side of the multiple pressure chambers 12, and the first extending portion 401A was arranged on the −Y direction side of the multiple pressure chambers 12. In contrast to this, the wiring portions 93a and 93b and the first extending portion 401A may be arranged on the +Y direction side of the multiple pressure chambers 12.

[0088] F. 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.

[0089] (1) According to one aspect of the present disclosure, there is provided a liquid ejection head. The liquid ejection head includes a pressure chamber substrate having a plurality of pressure chambers, individual electrodes provided for the plurality of pressure chambers, a common electrode provided in common to the plurality of pressure chambers, a piezoelectric element provided between the individual electrode and the common electrode for applying pressure to liquid in the pressure chamber, drive wiring electrically connected to the individual electrode 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 electrode, the common electrode, and the drive wiring for detecting the temperature of the liquid in the pressure chamber, and a sealing substrate having wall portions and a ceiling portion for protecting the piezoelectric element. When viewed along the stacking direction of the piezoelectric element, the individual electrodes, and the common electrode, the detection resistor is provided so that a portion overlapping the wall portion is shorter than a portion not overlapping the wall portion. According to this configuration of the liquid ejection head, by avoiding the placement of the wall portion of the sealing substrate in a position overlapping with the detection resistor, it is possible to prevent the heat from the detection resistor from being dissipated through the wall portion, thereby improving the accuracy of detecting the electrical resistance value by the detection resistor and improving the accuracy of detecting the temperature by the detection resistor.

[0090] (2) In the liquid ejection head of the above aspect, the detection resistor may be provided so as not to overlap with the wall portion when viewed along the stacking direction. With this liquid ejection head, it is possible to more reliably prevent heat from being dissipated from the detection resistor through the wall portion or the like, thereby further improving the accuracy of temperature detection by the detection resistor.

[0091] (3) In the liquid ejection head of the above aspect, the detecting resistor may be provided such that, when viewed along the stacking direction, a portion of the detecting resistor that overlaps with the ceiling portion is longer than a portion that does not overlap with the ceiling portion. According to the liquid ejection head of this aspect, by increasing the portion of the detecting resistor that is covered with the sealing substrate, it is possible to prevent the detecting resistor from being exposed to the outside air, foreign matter, etc.

[0092] (4) In the liquid ejection head of the above aspect, the detection resistor may be provided so as to overlap only with the ceiling portion when viewed along the stacking direction. According to this aspect of the liquid ejection head, by covering the entire detection resistor with a sealing substrate, it is possible to more reliably prevent the detection resistor from being exposed to the outside air, foreign matter, etc.

[0093] (5) In the liquid ejection head of the above aspect, the detection resistor may be formed of the same material as the individual electrodes. With this liquid ejection head, the detection resistor can be formed in the process of forming the individual electrodes, thereby simplifying the manufacturing process and reducing costs.

[0094] (6) 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.

[0095] (7) In the liquid ejection head of the above aspect, the detection resistor may be provided in an exposed state in a groove provided in the piezoelectric body. According to this aspect of the liquid ejection head, by covering the detection resistor with an air layer, it is possible to reduce or prevent heat radiation from the detection resistor.

[0096] (8) In the liquid ejection head of the above aspect, the detection resistor may be provided in a groove provided in the piezoelectric body and covered with an insulator. With this liquid ejection head, the detection resistor can be protected from condensation and foreign matter by the insulator film while suppressing heat dissipation from the detection resistor to a wall or the like.

[0097] (9) In the liquid ejection head of the above aspect, when the direction in which the plurality of pressure chambers are arranged is defined as an arrangement direction and the direction perpendicular to both the arrangement direction and the stacking direction is defined as an intersecting direction, the detection resistor may include a first extension portion that extends along the intersecting direction at a position on one side of the plurality of pressure chambers in the arrangement direction, and a second extension portion that is continuous with the first extension portion and extends along the arrangement direction. According to the liquid ejection head of this aspect, by arranging the second extension portion along the arrangement direction of the plurality of pressure chambers, the detection resistor can be arranged efficiently from the perspective of temperature detection of the plurality of pressure chambers.

[0098] (10) In the liquid ejection head of the above aspect, the detection resistor may further include a third extension portion that extends along the intersecting direction at a position on the other side of the pressure chambers in the arrangement direction. According to the liquid ejection head of this aspect, the detection resistor can be arranged efficiently by arranging the detection resistor so as to surround the pressure chambers.

[0099] (11) In the liquid ejection head of the above aspect, the common electrode may contain iridium, and the individual electrodes may contain platinum.

[0100] (12) According to another aspect of the present disclosure, there is provided a liquid ejection device. The liquid ejection device includes the liquid ejection head of the above aspect and a control unit that controls the ejection operation of the liquid ejection head. With this aspect of the liquid ejection device, it is possible to provide a liquid ejection device that can suppress heat dissipation from the detection resistor through a wall portion and improve the accuracy of temperature detection by the detection resistor.

[0101] 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.

[0102] 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.

[0103] 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) The main agent and hardener of adhesives. (2) Base paints and thinners, and clear paints and thinners. (3) A main solvent and a dilution solvent containing cells for the cell ink. (4) Metallic leaf pigment dispersion and dilution solvent for ink (metallic ink) that exhibits a metallic luster. (5) Gasoline, diesel and biofuels for vehicles. (6) The active ingredient and protective ingredient of a drug. (7) Phosphors and encapsulants for light-emitting diodes (LEDs). [Explanation of symbols]

[0104] 10...pressure chamber substrate, 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...sealing substrate, 30T...ceiling portion, 30W...wall portion, 31...holding portion, 32...through hole, 39...adhesive, 40...case member, 41...accommodating portion, 42...third manifold portion, 43...connection port, 44...supply port, 45...compliance substrate, 46...sealing film, 47...fixed substrate, 48...opening, 49...compliance portion, 50...diaphragm, 55...elastic film, 56...insulating film, 60...first electrode, 60b...end, 70...piezoelectric body, 70G...groove portion, 70H...through hole, 70a...end, 70b...end, 80...second electrode, 80b...end, 85...wiring portion, 91...individual lead electrode, 92...common lead electrode, 92a...extension portion, 92b...extension portion, 93...measurement lead electrode, 93H...contact hole, 93a, 93a1, 93a 2, 93b, 93b1, 93b2...wiring section, 96...wiring section, 100...manifold, 120...relay board, 121...integrated circuit, 300...piezoelectric element, 400...temperature acquisition section, 401, 401b1, 401b2...detection resistor, 401A, 401A1, 401A2...first extension section, 401B, 401B1, 401B2...second extension section, 401C...third extension section, 401T...overlapping section, 402...low thermal conductive layer, 405...insulator film, 430...current application circuit, 440...voltage detection Circuit, 450... temperature calculation unit, 460... memory unit, 500... liquid ejection device, 510, 510b, 510c, 510d... 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 in which a plurality of pressure chambers are provided; 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 electrode 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 one of the individual electrodes, the common electrode, and the drive wiring, for detecting the temperature of the liquid in the pressure chamber; a sealing substrate having a wall portion and a ceiling portion, the wall portion and the ceiling portion protecting the piezoelectric body, the detection resistor is provided such that a portion overlapping with the wall portion is shorter than a portion not overlapping with the wall portion when viewed along a stacking direction of the piezoelectric body, the individual electrode, and the common electrode; When the direction in which the plurality of pressure chambers are arranged is defined as an arrangement direction, and a direction perpendicular to both the arrangement direction and the stacking direction is defined as a cross direction, The detection resistor is a first extending portion extending along the intersecting direction at a position on one side of the plurality of pressure chambers in the arrangement direction; a second extending portion that is continuous with the first extending portion and extends along the arrangement direction.

2. The liquid ejection head according to claim 1 , wherein the detection resistor is provided so as not to overlap the wall portion when viewed along the stacking direction.

3. 3. The liquid ejection head according to claim 1, wherein the detection resistor is arranged so that, when viewed along the stacking direction, the portion overlapping with the ceiling portion is longer than the portion not overlapping with the ceiling portion.

4. The liquid ejection head according to claim 3 , wherein the detection resistor is provided so as to overlap only with the ceiling portion when viewed along the stacking direction.

5. The liquid ejection head according to claim 1 , wherein the detection resistor is made of the same material as the individual electrodes.

6. 6. The liquid ejection head according to claim 5, 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.

7. The liquid ejection head according to claim 6 , wherein the detection resistor is provided in an exposed state in a groove provided in the piezoelectric body.

8. The liquid ejection head according to claim 6 , wherein the detection resistor is provided in a groove provided in the piezoelectric body and is covered with an insulator.

9. A liquid ejection head described in any one of claims 1 to 8, wherein the detection resistor further has a third extension portion extending along the intersecting direction at a position on the other side of the plurality of pressure chambers in the arrangement direction.

10. 10. The liquid ejection head according to claim 1, wherein the common electrode contains iridium, and the individual electrodes contain platinum.

11. The liquid ejection head according to any one of claims 1 to 10, a control unit that controls the ejection operation of the liquid ejection head.

12. A liquid ejection head, a pressure chamber substrate in which a plurality of pressure chambers are provided; 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 electrode 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 one of the individual electrodes, the common electrode, and the drive wiring, for detecting the temperature of the liquid in the pressure chamber; a sealing substrate having a wall portion and a ceiling portion, the wall portion and the ceiling portion protecting the piezoelectric body, the detection resistor is provided such that a portion overlapping with the wall portion is shorter than a portion not overlapping with the wall portion when viewed along a stacking direction of the piezoelectric body, the individual electrode, and the common electrode; the detection resistor is formed of the same material as the individual electrodes, the common electrode is provided on the upper part of the piezoelectric body, the individual electrodes are provided below the piezoelectric bodies, The liquid ejection head, wherein the detection resistor is provided in an exposed state in a groove provided in the piezoelectric body.

13. A liquid ejection head, a pressure chamber substrate in which a plurality of pressure chambers are provided; 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 electrode 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 one of the individual electrodes, the common electrode, and the drive wiring, for detecting the temperature of the liquid in the pressure chamber; a sealing substrate having a wall portion and a ceiling portion, the wall portion and the ceiling portion protecting the piezoelectric body, the detection resistor is provided such that a portion overlapping with the wall portion is shorter than a portion not overlapping with the wall portion when viewed along a stacking direction of the piezoelectric body, the individual electrode, and the common electrode; the detection resistor is formed of the same material as the individual electrodes, the common electrode is provided on the upper part of the piezoelectric body, the individual electrodes are provided below the piezoelectric bodies, The liquid ejection head, wherein the detection resistor is provided in a groove provided in the piezoelectric body and is covered with an insulator.

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