Liquid ejection head and liquid ejection device

Abstract

To prevent accuracy of temperature measurement from decreasing due to a resistor even in a case where the resistor for measuring a temperature and a piezoelectric body are used together.SOLUTION: A liquid ejection head comprises: a pressure chamber substrate provided with a plurality of pressure chambers; a piezoelectric body which is driven to apply a pressure to a liquid in the plurality of pressure chambers and contains lead atoms; a first electrode provided on a first surface of two surfaces of the piezoelectric body; a second electrode provided on a second surface of the two surfaces of the piezoelectric body, which is opposite to the first surface; drive wiring electrically connected to the first electrode and the second electrode and configured to apply a voltage for driving the piezoelectric body; a resistor which is formed of the same material as any one of the first electrode, the second electrode, and the drive wiring and configured to measure a temperature of the liquid in the plurality of pressure chambers, and a diffusion prevention layer provided between the resistor and the piezoelectric body and configured to prevent the lead atoms contained in the piezoelectric body from diffusing into the resistor.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A liquid ejection head of a liquid ejection device such as a piezoelectric inkjet printer has a pressure chamber filled with liquid and a piezoelectric element for applying pressure to the liquid in the pressure chamber. For example, Patent Document 1 discloses a liquid ejection device having a liquid ejection head and a resistor for measuring the temperature of the liquid in the liquid ejection device. [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, in the conventional technology, when a resistor and a piezoelectric element are used together to measure temperature, there is a problem that the accuracy of temperature measurement by the resistor may be reduced. [Means for solving the problem]

[0005] In order to solve the above problems, the liquid ejection head of the present invention is characterized by having a pressure chamber substrate having a plurality of pressure chambers; a piezoelectric body containing lead atoms and driven to apply pressure to the liquid in the plurality of pressure chambers; a first electrode provided on a first of two surfaces of the piezoelectric body; a second electrode provided on a second of two surfaces of the piezoelectric body opposite to the first surface; drive wiring electrically connected to the first electrode and the second electrode and applying a voltage to drive the piezoelectric body; a resistor formed of the same material as any of the first electrode, the second electrode, and the drive wiring and used to measure the temperature of the liquid in the plurality of pressure chambers; and a diffusion suppression layer provided between the resistor and the piezoelectric body for suppressing diffusion of lead atoms contained in the piezoelectric body into the resistor.

[0006] A liquid ejection apparatus according to the present invention includes the above-described liquid ejection head and a control unit that controls the ejection operation from the liquid ejection head. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating a liquid ejection device 100 according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the liquid ejection head 1. [Figure 3] 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 2 is a plan view of the liquid ejection head 1. [Figure 5] Cross-sectional view of line jJ in Figure 4. [Figure 6] 5 is a cross-sectional view of line kK in FIG. 4. [Figure 7] Cross-sectional view of line mM in Figure 4. [Figure 8] FIG. 10 is a diagram illustrating a liquid ejection head 1-A according to a second embodiment. [Figure 9] FIG. 10 is a diagram illustrating a liquid ejection head 1-B according to a third embodiment. [Figure 10] FIG. 10 is a diagram illustrating a liquid ejection head 1-C according to a fourth embodiment. [Figure 11] FIG. 10 is a plan view of a liquid ejection head 1-D according to a first modified example. [Figure 12] Cross-sectional view of line jJ in Figure 11. [Figure 13] FIG. 10 is a diagram illustrating a liquid ejection head 1-E according to a second modified example. [Figure 14] FIG. 10 is a diagram illustrating a liquid ejection head 1-F according to a third modified example. [Figure 15] FIG. 10 is a diagram illustrating a liquid ejection head 1-G according to a fourth modified example. [Figure 16] FIG. 11 is a plan view of a liquid ejection head 1-H according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part are appropriately different from those of the actual parts. Furthermore, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0009] 1. First embodiment 1.1. Overview of the liquid ejection device 1 is a schematic diagram illustrating a liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects ink onto a medium PP. The medium PP is typically printing paper, but any printing target such as a resin film or fabric can also be used as the medium PP.

[0010] The liquid ejection device 100 includes a liquid container 93 that stores ink. The liquid container 93 may be, for example, a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of flexible film, or an ink tank that can be refilled with ink. The liquid container 93 stores a plurality of types of ink with different colors.

[0011] The liquid ejection device 100 includes a plurality of liquid ejection heads 1, a control unit 7, a detection device 8, a movement mechanism 91, a transport mechanism 92, and a circulation mechanism 94.

[0012] The control unit 7 includes a processing circuit such as a CPU or FPGA, and a storage circuit such as a semiconductor memory, and controls each element of the liquid ejection device 100. Here, CPU is an abbreviation for Central Processing Unit, and FPGA is an abbreviation for Field Programmable Gate Array. Various programs and data are stored in the storage circuit.

[0013] The movement mechanism 91 transports the medium PP in the Y1 direction along the Y axis under the control of the control unit 7. Hereinafter, the Y1 direction and the Y2 direction opposite to the Y1 direction will be collectively referred to as the Y-axis direction. Hereinafter, the X1 direction along the X axis intersecting the Y axis and the X2 direction opposite to the X1 direction will be collectively referred to as the X-axis direction. Hereinafter, the Z1 direction along the Z axis intersecting the X and Y axes and the Z2 direction opposite to the Z1 direction will be collectively referred to as the Z-axis direction. In this embodiment, as an example, a case will be described in which the X axis, Y axis, and Z axis are orthogonal to one another. However, the present invention is not limited to this example. It is sufficient that the X axis, Y axis, and Z axis intersect with one another.

[0014] The transport mechanism 92 reciprocates the plurality of liquid ejection heads 1 in the X1 and X2 directions under the control of the control unit 7. The transport mechanism 92 includes a storage case 921 that houses the plurality of liquid ejection heads 1, and an endless belt 922 to which the storage case 921 is fixed. Note that the liquid container 93 may be stored in the storage case 921 together with the liquid ejection heads 1.

[0015] The circulation mechanism 94 supplies the ink stored in the liquid container 93 to the liquid ejection head 1 under the control of the control unit 7. The circulation mechanism 94 also recovers the ink stored in the liquid ejection head 1 under the control of the control unit 7, and returns the recovered ink to the liquid ejection head 1.

[0016] The control unit 7 controls the ejection operation from the liquid ejection head 1. Specifically, the control unit 7 supplies the liquid ejection head 1 with a drive signal Com for driving the liquid ejection head 1 and a control signal SI for controlling the liquid ejection head 1. The liquid ejection head 1 is driven by the drive signal Com under the control of the control signal SI, causing some or all of the nozzles N provided in the liquid ejection head 1 to eject ink in the Z1 direction. That is, the liquid ejection head 1 ejects ink from some or all of the nozzles N in conjunction with the transport of the medium PP by the movement mechanism 91 and the reciprocating movement of the liquid ejection head 1 by the transport mechanism 92, and causes the ejected ink to land on the surface of the medium PP, thereby executing a printing process to form a desired image on the surface of the medium PP. The nozzles N will be described later with reference to FIGS. 2 and 3.

[0017] The liquid ejection head 1 performs maintenance processes separately from the printing process. One of the maintenance processes is a flushing process. The flushing process is a process in which the liquid ejection head 1 is repeatedly driven by a maintenance drive signal Com to forcibly remove thickened ink and air bubbles mixed in the ink. If air bubbles mix with the ink, the air bubbles may absorb pressure fluctuations, resulting in ink not being ejected from the nozzle N (so-called missing dots), or ejection defects such as deflected flight. By performing the flushing process, missing dots and ejection defects can be prevented.

[0018] The detection device 8 includes a current supply circuit 81 and a voltage detection circuit 82.

[0019] The current supply circuit 81 supplies a current I0 to the liquid ejection head 1. In this embodiment, the current I0 is a constant current of a predetermined magnitude. In this embodiment, it is assumed that part or all of the current I0 supplied from the current supply circuit 81 to the liquid ejection head 1 flows from one end to the other end of a detection resistor TK provided in the liquid ejection head 1. The detection resistor TK will be described later with reference to Figures 4, 6, and 7. The detection resistor TK is an example of a "resistor."

[0020] The voltage detection circuit 82 detects the voltage VK applied to the detection resistor TK. Here, the voltage VK is the potential difference between one end and the other end of the detection resistor TK. Specifically, in this embodiment, the voltage detection circuit 82 detects the voltage VK across the detection resistor TK when part or all of the current I0 supplied from the current supply circuit 81 flows from one end to the other end of the detection resistor TK. The voltage detection circuit 82 outputs a detection result signal DK having a value corresponding to the voltage VK detected from the detection resistor TK to the control unit 7.

[0021] In this embodiment, an example is described in which the current supply circuit 81 and the voltage detection circuit 82 are provided outside the liquid ejection head 1, but the present invention is not limited to this example. The current supply circuit 81 and the voltage detection circuit 82 may also be provided in the liquid ejection head 1.

[0022] The processing circuit provided in the control unit 7 can function as the temperature specifying unit 71 and the signal adjusting unit 72 by reading out the program stored in the storage circuit and executing this program. The temperature specifying unit 71 specifies the temperature of the ink inside the liquid ejection head 1 based on the detection result signal DK. The signal adjusting unit 72 adjusts the maintenance drive signal Com based on the temperature identified by the temperature identifying unit 71. For example, the signal adjusting unit 72 increases the number of pulses included in the maintenance drive signal Com as the temperature identified by the temperature identifying unit 71 increases.

[0023] 1.2. Overview of liquid ejection head The liquid ejection head 1 will now be outlined with reference to FIGS.

[0024] Fig. 2 is an exploded perspective view of the liquid ejection head 1. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.

[0025] As shown in Figures 2 and 3, the liquid ejection head 1 includes a nozzle substrate 21, compliance sheets CS1 and CS2, a communication plate 22, a pressure chamber substrate 23, a vibration plate 24, a sealing substrate 25, a flow path forming substrate 26, and a wiring substrate 4.

[0026] As shown in Fig. 2, the nozzle substrate 21 is a plate-like member that is long in the Y-axis direction and extends approximately parallel to the XY plane. Here, "approximately parallel" is a concept that includes not only completely parallel, but also a case where it can be considered to be parallel when an error is taken into consideration. In this embodiment, "approximately parallel" is a concept that includes a case where it can be considered to be parallel when an error of about 10% is taken into consideration. The nozzle substrate 21 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing techniques such as etching, but known materials and manufacturing methods may be arbitrarily adopted for manufacturing the nozzle substrate 21.

[0027] A plurality of nozzles N are formed on the nozzle substrate 21. Here, the nozzles N are through-holes provided in the nozzle substrate 21. In this embodiment, it is assumed that the plurality of nozzles N formed on the nozzle substrate 21 include a plurality of nozzles N1 arranged to extend in the Y-axis direction and a plurality of nozzles N2 arranged to extend in the Y-axis direction at positions in the X2 direction as viewed from the plurality of nozzles N1. Hereinafter, the plurality of nozzles N1 extending in the Y-axis direction will be referred to as a nozzle row Ln1, and the plurality of nozzles N2 extending in the Y-axis direction will be referred to as a nozzle row Ln2. Furthermore, hereinafter, the nozzle row Ln1 and the nozzle row Ln2 may be collectively referred to as a nozzle row Ln.

[0028] 2 and 3, a communicating plate 22 is provided at a position in the Z2 direction as viewed from the nozzle substrate 21. The communicating plate 22 is a plate-shaped member that is long in the Y-axis direction and extends approximately parallel to the XY plane. The communicating plate 22 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the communicating plate 22 may be manufactured using any known material and method.

[0029] Ink flow paths are formed in the communication plate 22. Specifically, the communication plate 22 is formed with one supply flow path BA1 extending in the Y-axis direction and one supply flow path BA2 extending in the Y-axis direction at a position in the X2 direction as viewed from the supply flow path BA1. The communication plate 22 also is formed with a plurality of connection flow paths BK1 corresponding to the plurality of nozzles N1, a plurality of connection flow paths BK2 corresponding to the plurality of nozzles N2, a plurality of communication flow paths BR1 corresponding to the plurality of nozzles N1, and a plurality of communication flow paths BR2 corresponding to the plurality of nozzles N2.

[0030] Of these, the connection flow path BK1 communicates with the supply flow path BA1 and is provided so as to extend in the Z-axis direction at a position in the X2 direction as viewed from the supply flow path BA1. The communication flow path BR1 is provided so as to extend in the Z-axis direction at a position in the X2 direction as viewed from the connection flow path BK1. The communication flow path BR1 communicates with the nozzle N1 corresponding to the communication flow path BR1. The connection flow path BK2 communicates with the supply flow path BA2 and is provided so as to extend in the Z-axis direction at a position in the X1 direction as viewed from the supply flow path BA2. The communication flow path BR2 is provided so as to extend in the Z-axis direction at a position in the X1 direction as viewed from the connection flow path BK2 and at a position in the X2 direction as viewed from the communication flow path BR1. The communication flow path BR2 communicates with the nozzle N2 corresponding to the communication flow path BR2. In the following, the supply flow paths BA1 and BA2 may be collectively referred to as the supply flow paths BA. In the following, the connection flow paths BK1 and BK2 may be collectively referred to as the connection flow paths BK. In the following, the communication flow paths BR1 and BR2 may be collectively referred to as the communication flow path BR.

[0031] 2 and 3, a pressure chamber substrate 23 is provided at a position in the Z2 direction as viewed from the communication plate 22. The pressure chamber substrate 23 is a plate-shaped member that is long in the Y-axis direction and extends approximately parallel to the XY plane. The pressure chamber substrate 23 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the pressure chamber substrate 23 may be manufactured using any known material and manufacturing method.

[0032] Ink flow paths are formed in the pressure chamber substrate 23. Specifically, the pressure chamber substrate 23 is formed with a plurality of pressure chambers CV1 corresponding to the plurality of nozzles N1 and a plurality of pressure chambers CV2 corresponding to the plurality of nozzles N2. Of these, the pressure chamber CV1 is provided so as to connect the X2-direction end of the connection flow path BK1 and the X1-direction end of the communication flow path BR1 and extend in the X-axis direction when viewed in the Z-axis direction. The pressure chamber CV2 is provided so as to connect the X1-direction end of the connection flow path BK2 and the X2-direction end of the communication flow path BR2 when viewed in the Z-axis direction and extend in the X-axis direction. Note that hereinafter, the pressure chamber CV1 and the pressure chamber CV2 may be collectively referred to as pressure chamber CV.

[0033] 2 and 3, a diaphragm 24 is provided at a position in the Z2 direction as viewed from the pressure chamber substrate 23. The diaphragm 24 is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane, and is a member that can elastically vibrate. In this embodiment, of the two faces of the diaphragm 24 whose normal direction is the Z-axis direction, the face in the Z2 direction is formed from a non-conductive member. Specifically, the diaphragm 24 has an elastic layer made of silicon oxide and an insulating layer made of zirconium oxide provided at a position in the Z2 direction as viewed from the elastic layer.

[0034] As shown in FIGS. 2 and 3, a plurality of piezoelectric elements PZ1 corresponding to a plurality of pressure chambers CV1 and a plurality of piezoelectric elements PZ2 corresponding to a plurality of pressure chambers CV2 are provided at positions in the Z2 direction as viewed from the vibration plate 24. Hereinafter, the piezoelectric elements PZ1 and PZ2 may be collectively referred to as the piezoelectric element PZ. The piezoelectric element PZ is a passive element that deforms in response to a change in the potential of the drive signal Com. In other words, the piezoelectric element PZ is an example of an energy conversion element that converts the electrical energy of the drive signal Com into kinetic energy. Specifically, the piezoelectric element PZ is driven and deforms in response to a change in the potential of the drive signal Com. The vibration plate 24 vibrates in conjunction with the deformation of the piezoelectric element PZ. When the vibration plate 24 vibrates, the pressure in the pressure chamber CV fluctuates. The fluctuation in the pressure in the pressure chamber CV causes ink filled inside the pressure chamber CV to be ejected from the nozzle N via the communication channel BR.

[0035] 2 and 3, a sealing substrate 25 for protecting the plurality of piezoelectric elements PZ1 and the plurality of piezoelectric elements PZ2 is provided at a position in the Z2 direction as viewed from the pressure chamber substrate 23. The sealing substrate 25 is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The sealing substrate 25 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the sealing substrate 25 may be manufactured using any known material and method.

[0036] The sealing substrate 25 has two surfaces normal to the Z-axis direction, and the surface facing the Z1 direction has recesses for covering the piezoelectric elements PZ1 and recesses for covering the piezoelectric elements PZ2. Hereinafter, the sealed space covering the piezoelectric elements PZ1 and formed between the vibration plate 24 and the sealing substrate 25 will be referred to as the sealed space SP1, and the sealed space covering the piezoelectric elements PZ2 and formed between the vibration plate 24 and the sealing substrate 25 will be referred to as the sealed space SP2. Hereinafter, the sealed spaces SP1 and SP2 may be collectively referred to as the sealed space SP. The sealed space SP is a space for sealing the piezoelectric elements PZ and preventing deterioration of the piezoelectric elements PZ due to moisture and the like. Hereinafter, when the sealing substrate 25 is viewed from above in the Z1 direction, the side walls of the sealed space SP1 will be referred to as the side walls WL1, and the side walls of the sealed space SP2 will be referred to as the side walls WL2. In the following description, the side wall WL1 and the side wall WL2 may be collectively referred to as the side wall WL.

[0037] A through hole 250 is provided in the sealing substrate 25. When the sealing substrate 25 is viewed in the Z1 direction, the through hole 250 is located between the sealed space SP1 and the sealed space SP2, and is a hole that penetrates from the Z1 direction surface of the sealing substrate 25 to the Z2 direction surface of the sealing substrate 25. The wiring substrate 4 is inserted into the through hole 250.

[0038] 2 and 3, a flow path forming substrate 26 is provided at a position in the Z2 direction as viewed from the communication plate 22. The flow path forming substrate 26 is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The flow path forming substrate 26 is formed, for example, by injection molding of a resin material, but the flow path forming substrate 26 may be manufactured using any known material and method.

[0039] Ink flow channels are formed in the flow channel forming substrate 26. Specifically, one supply channel BB1 and one supply channel BB2 are formed in the flow channel forming substrate 26. Of these, supply channel BB1 communicates with supply channel BA1 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction as viewed from supply channel BA1. Supply channel BB2 communicates with supply channel BA2 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction as viewed from supply channel BA2 and at a position in the X2 direction as viewed from supply channel BB1. Note that, hereinafter, supply channel BB1 and supply channel BB2 may be collectively referred to as supply channel BB.

[0040] The flow path forming substrate 26 is provided with an inlet HL1 communicating with the supply flow path BB1 and an inlet HL2 communicating with the supply flow path BB2. Ink is supplied to supply flow channel BB1 from the liquid container 93 via inlet HL1. The ink supplied to supply flow channel BB1 from the liquid container 93 via inlet HL1 flows into supply flow channel BA1. Some of the ink that flows into supply flow channel BA1 passes through connecting flow channel BK1 and fills pressure chamber CV1. When piezoelectric element PZ1 is driven by drive signal Com, some of the ink that has filled pressure chamber CV1 passes through communicating flow channel BR1 and is ejected from nozzle N1. Furthermore, ink is supplied to supply flow channel BB2 from the liquid container 93 via inlet HL2. The ink supplied to supply flow channel BB2 from the liquid container 93 via inlet HL2 flows into supply flow channel BA2. Some of the ink that flows into supply flow channel BA2 passes through connecting flow channel BK2 and fills pressure chamber CV2. When piezoelectric element PZ2 is driven by drive signal Com, some of the ink that has filled pressure chamber CV2 is ejected from nozzle N2 via communicating flow channel BR2.

[0041] A through hole 260 is provided in the flow path forming substrate 26. When the flow path forming substrate 26 is viewed in the Z1 direction, the through hole 260 is located between the supply flow path BB1 and the supply flow path BB2, and is a hole that penetrates from the Z1 direction surface of the flow path forming substrate 26 to the Z2 direction surface of the flow path forming substrate 26. The wiring substrate 4 is inserted into the through hole 260.

[0042] As shown in Figures 2 and 3, a wiring board 4 is mounted on the Z2 direction surface of the vibration plate 24. The wiring board 4 is a component for electrically connecting the liquid ejection head 1 to the control unit 7. As the wiring board 4, for example, a flexible wiring board such as an FPC or FFC is preferably used. Here, FPC is an abbreviation for Flexible Printed Circuit, and FFC is an abbreviation for Flexible Flat Cable. An integrated circuit 40 is mounted on the wiring board 4. The integrated circuit 40 is an electric circuit that switches whether or not to supply a drive signal Com to the piezoelectric element PZ under the control of a control signal SI.

[0043] 2 and 3, a compliance sheet CS1 is provided in a position in the Z1 direction as viewed from the communicating plate 22 so as to block the supply flow path BA1 and the connecting flow path BK1, and a compliance sheet CS2 is provided so as to block the supply flow path BA2 and the connecting flow path BK2. Hereinafter, the compliance sheets CS1 and CS2 may be collectively referred to as the compliance sheet CS. The compliance sheet CS is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The compliance sheet CS is made of an elastic material and absorbs pressure fluctuations of the ink in the supply flow path BA and the connecting flow path BK.

[0044] 1.3.Detection resistor TK The detection resistor TK is disposed close to the pressure chamber CV, thereby enabling more accurate measurement of the temperature of the ink in the pressure chamber CV. In the first embodiment, the detection resistor TK is provided between the piezoelectric body Qm, which is part of the piezoelectric element PZ, and the vibration plate 24, and is provided at a position overlapping the pressure chamber CV when the liquid ejection head 1 is viewed in a plan view in the Z1 direction. The detection resistor TK will be described below with reference to FIGS. 4, 6, and 7.

[0045] 1.3.1. Structure of the detection resistor TK Fig. 4 is a plan view of the liquid ejection head 1 when viewed in the Z1 direction. Fig. 5 is a cross-sectional view taken along line jJ in Fig. 4. However, for ease of explanation, Fig. 4 omits the illustration of the flow path forming substrate 26 and the integrated circuit 40. Furthermore, Fig. 4 also conveniently illustrates the periphery of an element located behind any one element, i.e., a portion that would normally be hidden by an element in front.

[0046] 4, when the liquid ejection head 1 is viewed in a plane in the Z1 direction, a plurality of pressure chambers CV1 corresponding to the plurality of nozzles N1, a plurality of individual electrodes Qc corresponding to the plurality of nozzles N1, a plurality of individual wires Lc corresponding to the plurality of nozzles N1, a piezoelectric element Qm, a common electrode Qb, a common wire Lb, a detection resistor TK, a detection wire LK1, and a detection wire LK2 are provided at positions overlapping with a sealed space SP1, which is a space located inside a side wall WL1 of the sealing substrate 25. The plurality of individual wires Lc and the common wire Lb are an example of "drive wires."

[0047] Here, the dimensions of each part in FIG. 4 are merely examples, and the actual dimensions may differ. For example, the area where the individual electrode Qc, the piezoelectric element Qm, and the common electrode Qb overlap when viewed from the Z-axis direction corresponds to the area where the diaphragm 24 vibrates, the so-called active area. The width of this active area in the X-axis direction may be longer than the width shown in FIG. 4. A longer width of this area in the X-axis direction increases the width over which the diaphragm 24 can vibrate, and therefore increases the amount of vibration, which is preferable in terms of ejection characteristics. The ejection characteristics are one or both of the ejection amount and the ejection speed.

[0048] 4, the common electrode Qb is formed so as not to overlap with resistor extension portions Tky1, Tky2, and TKy3, which will be described later, when viewed from the Z-axis direction, but it may be formed so as to overlap with the resistor extension portions TKy1, TKy2, and TKy3. In other words, the width in the X-axis direction of the portion of the common electrode Qb extending in the Y-axis direction may be longer than that shown in FIG. 4, and as a result, the common electrode Qb may overlap with the resistor extension portions TKy1, TKy2, and TKy3.

[0049] 4, the common electrode Qb and the common wiring Lb completely overlap when viewed from the Z-axis direction, in other words, are positioned in the same positional relationship on the XY plane, but they may be different. For example, the common electrode Qb may remain as shown in FIG. 4, and the common wiring Lb may be shaped so that it branches into two at the portion extending in the Y-axis direction.

[0050] The detection resistor TK is a resistive wiring used to measure the temperature of the ink in the pressure chamber CV1, and the electrical resistance of the detection resistor TK changes depending on the temperature of the detection resistor TK. The temperature specifying unit 71 utilizes the property of the detection resistor TK that the electrical resistance changes depending on the temperature of the detection resistor TK to estimate the temperature of the ink in the pressure chamber CV1 based on the detection result signal DK having a value corresponding to the voltage VK detected from the detection resistor TK.

[0051] One end of the detection resistor TK is connected to a contact hole CH1 of the detection wiring LK1. The detection resistor TK is electrically connected to a wiring provided on the wiring board 4 via the detection wiring LK1. The other end of the detection resistor TK is connected to a contact hole CH2 of the detection wiring LK2. The detection resistor TK is electrically connected to a wiring provided on the wiring board 4 via the detection wiring LK2.

[0052] The detection resistor TK includes a resistor extending portion TKx1, a resistor extending portion TKy1, a resistor extending portion TKy2, a resistor extending portion TKy3, and a resistor extending portion TKx2.

[0053] The resistor extension portion TKx1 extends in the X-axis direction. One end of the resistor extension portion TKx1 is connected to the contact hole CH1 of the detection wiring LK1, and the other end is connected to the resistor extension portion TKy1. The resistor extension portion TKy1 extends in the Y-axis direction. One end of the resistor extension portion TKy1 is connected to the resistor extension portion TKx1, and the other end is connected to the resistor extension portion TKy2. The resistor extension portion TKy2 extends in the Y-axis direction at a position closer to the wiring board 4 than the resistor extension portion TKy1. One end of the resistor extension portion TKy2 is connected to the resistor extension portion TKy1, and the other end is connected to the resistor extension portion TKy3. The resistor extension portion TKy3 extends in the Y-axis direction at a position closer to the wiring board 4 than the resistor extension portion TKy2. One end of resistor extension portion TKy3 is connected to resistor extension portion TKy2, and the other end is connected to resistor extension portion TKx2. Resistor extension portion TKx2 extends in the X-axis direction at a position in the Y1 direction further than resistor extension portion TKx1. One end of resistor extension portion TKx2 is connected to contact hole CH2 of detection wiring LK2, and the other end is connected to resistor extension portion TKy3.

[0054] A current I0, which is a constant current of a predetermined magnitude, is supplied to the detection wiring LK1 from the current supply circuit 81 via wiring on the wiring board 4. Furthermore, wiring on the wiring board 4 that is set to ground potential is electrically connected to the detection wiring LK2. Therefore, the current I0 supplied to the detection wiring LK1 flows from the detection wiring LK1 through resistor extension portion TKx1, resistor extension portion TKy1, resistor extension portion TKy2, resistor extension portion TKy3, resistor extension portion TKx2, and the detection wiring LK2, to wiring on the wiring board 4 to which the detection wiring LK2 is electrically connected.

[0055] The detection resistor TK is made of a conductive material whose electrical resistance is temperature dependent, such as gold, platinum, iridium, aluminum, copper, titanium, tungsten, nickel, or chromium. The detection wiring LK1 and the detection wiring LK2 are formed from a conductive material. Examples of materials that can be used for the detection wiring LK1 and the detection wiring LK2 include gold, copper, titanium, tungsten, nickel, chromium, platinum, and aluminum. In this embodiment, the detection wiring LK1 and the detection wiring LK2 are formed from a material with a lower electrical resistance than the detection resistor TK. This makes it possible to accurately determine the voltage VK across the detection resistor TK compared to an embodiment in which the detection wiring LK1 and the detection wiring LK2 are formed from a material with a higher electrical resistance than the detection resistor TK. However, the present invention is not limited to this embodiment. For example, the detection wiring LK1 and the detection wiring LK2 may be formed from the same material as the detection resistor TK.

[0056] The common wiring Lb includes a partial wiring Lb1, a partial wiring Lb2, and a partial wiring Lb3.

[0057] The partial wiring Lb1 extends in the X-axis direction. One end of the partial wiring Lb1 is electrically connected to a wiring provided on the wiring substrate 4, and the other end is connected to the partial wiring Lb2. The partial wiring Lb2 extends in the Y-axis direction. One end of the partial wiring Lb2 is connected to the partial wiring Lb1, and the other end is connected to the partial wiring Lb3. The partial wiring Lb3 extends in the X-axis direction. One end of the partial wiring Lb3 is connected to the partial wiring Lb2, and the other end is electrically connected to a wiring provided on the wiring substrate 4.

[0058] The wiring on the wiring board 4 to which the partial wiring Lb1 is electrically connected and the wiring on the wiring board 4 to which the partial wiring Lb3 is electrically connected are set to a predetermined reference potential VBS. Therefore, the potential of the common wiring Lb is also set to the reference potential VBS.

[0059] The common electrode Qb is provided in a region overlapping with the partial wiring Lb2 when the liquid ejection head 1 is viewed in a plane in the Z1 direction. In this embodiment, the common electrode Qb is provided in common to a plurality of pressure chambers CV1. More specifically, the common electrode Qb is provided so as to overlap with a plurality of pressure chambers CV1 when the liquid ejection head 1 is viewed in a plane in the Z1 direction. The common electrode Qb is provided so that some or all of the plurality of pressure chambers CV1 have portions that do not overlap with the common electrode Qb when the liquid ejection head 1 is viewed in a plane in the Z1 direction.

[0060] 5, the common electrode Qb is provided on a surface PL1 of the piezoelectric body Qm. In the first embodiment, the common electrode Qb is a so-called upper electrode.

[0061] The common electrode Qb is connected to the partial wiring Lb2. Therefore, the potential of the common electrode Qb is set to the reference potential VBS. Here, in the first embodiment, the common electrode Qb is an example of a "first electrode."

[0062] The common electrode Qb is made of a conductive material, such as a metal, such as platinum, iridium, gold, or titanium, or a conductive metal oxide, such as indium tin oxide (ITO). The common wiring Lb is made of a conductive material, such as gold, copper, titanium, tungsten, nickel, chromium, platinum, or aluminum.

[0063] The piezoelectric body Qm is provided in common to the multiple pressure chambers CV1. More specifically, the piezoelectric body Qm is provided so as to overlap the multiple pressure chambers CV1 when the liquid ejection head 1 is viewed in a plane in the Z1 direction. However, the piezoelectric body Qm may be provided so that some or all of the multiple pressure chambers CV1 have portions that do not overlap with the piezoelectric body Qm when the liquid ejection head 1 is viewed in a plane in the Z1 direction.

[0064] The piezoelectric body Qm is formed, for example, from a perovskite-structured crystalline film made of a ferroelectric ceramic material exhibiting electromechanical transduction, i.e., a perovskite-type crystal. Specifically, the material for the piezoelectric body Qm can be, for example, a ferroelectric piezoelectric material such as lead zirconate titanate, or a ferroelectric piezoelectric material such as lead zirconate titanate to which a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide has been added. More specifically, the material for the piezoelectric body Qm can be, for example, lead titanate, lead zirconate titanate, lead zirconate, lead lanthanum titanate, lead lanthanum zirconate titanate, or magnesium zirconium niobate titanate. That is, the piezoelectric body Qm is composed of a lead compound and contains lead atoms. The piezoelectric body Qm can be formed by forming the above-mentioned piezoelectric material by a known film forming technique such as sputtering, and then firing the piezoelectric material at a high temperature by a known processing technique such as photolithography.

[0065] As described above, the liquid ejection head 1 is provided with a plurality of individual electrodes Qc corresponding to the plurality of pressure chambers CV1. The liquid ejection head 1 is also provided with a plurality of individual wirings Lc corresponding to the plurality of individual electrodes Qc. A drive signal Com is supplied to each individual wiring Lc from the control unit 7 via wiring provided on the wiring substrate 4. As illustrated in FIG. 5, the individual electrode Qc is provided on the surface PL2 of the piezoelectric body Qm. In the first embodiment, the individual electrode Qc is a so-called lower electrode. Note that in the first embodiment, the individual electrode Qc is an example of a "second electrode."

[0066] The individual wirings Lc are made of a conductive material, such as gold, copper, titanium, tungsten, nickel, chromium, platinum, or aluminum. The individual electrodes Qc are formed from a conductive material. Specifically, the individual electrodes Qc may be formed from a conductive material such as a metal such as platinum, iridium, gold, or titanium, or a conductive metal oxide such as indium tin oxide (ITO). In this embodiment, as an example, it is assumed that the detection resistor TK is formed from the same material as the individual electrodes Qc and the common electrode Qb. Specifically, in this embodiment, as an example, it is assumed that the detection resistor TK, the individual electrodes Qc, and the common electrode Qb are formed from platinum.

[0067] The piezoelectric element PZ is a laminate in which a piezoelectric body Qm is interposed between a common electrode Qb set to a reference potential VBS and an individual electrode Qc to which a drive signal Com is supplied. When the liquid ejection head 1 is viewed in a plane in the Z1 direction, the portion where the piezoelectric body Qm, the common electrode Qb, and the individual electrode Qc corresponding to one pressure chamber CV1 overlap corresponds to the piezoelectric element PZ corresponding to one pressure chamber CV1. The pressure chamber CV1 corresponding to the piezoelectric element PZ is provided at a position of the piezoelectric element PZ in the Z1 direction.

[0068] As described above, the piezoelectric element PZ is driven and deformed in response to changes in the potential of the drive signal Com. The vibration plate 24 vibrates in conjunction with the deformation of the piezoelectric element PZ. When the vibration plate 24 vibrates, the pressure inside the pressure chamber CV1 fluctuates. When the pressure inside the pressure chamber CV1 fluctuates, the ink filled inside the pressure chamber CV1 is ejected from the nozzle N1 via the communication flow path BR1.

[0069] 1.3.2. Role of the detection resistor TK The current I0 supplied from the current supply circuit 81 to the detection wiring LK1 flows through the detection resistor TK to the detection wiring LK2, which is set to ground potential. Therefore, the voltage VK applied between one end of the detection resistor TK connected to the detection wiring LK1 and the other end of the detection resistor TK connected to the detection wiring LK2 is expressed as "VK = I0 * RK" using the resistance value RK between one end and the other end of the detection resistor TK. In other words, when the current I0 is supplied from the current supply circuit 81 to the detection resistor TK through the detection wiring LK1, the voltage detection circuit 82 detects the voltage VK, which indicates the value "I0 * RK", from the detection resistor TK.

[0070] Because the resistance value RK changes depending on the temperature of the detection resistor TK, the temperature determination unit 71 can determine the temperature of the pressure chamber CV1 based on the detection result signal DK indicating the voltage VK detected by the voltage detection circuit 82. The temperature-dependent resistance value RK characteristic of the detection resistor TK can be determined by determining the material and shape of the detection resistor TK. The material and shape of the detection resistor TK are determined by the developer of the liquid ejection head 1. The memory circuit of the control unit 7 stores a table showing the relationship between the multiple temperatures that the detection resistor TK can assume and the resistance value RK at each of the multiple temperatures that the detection resistor TK can assume. Note that because the current IO is a predetermined magnitude, the resistance value RK and the voltage VK are proportional to each other. Therefore, the memory circuit of the control unit 7 may store a table showing the relationship between the multiple temperatures that the detection resistor TK can assume and the voltage VK at each of the multiple temperatures that the detection resistor TK can assume. For ease of understanding, the following description will be given assuming that the memory circuit of the control unit 7 stores a table showing the relationship between the multiple temperatures that the detection resistor TK can assume and the resistance value RK at each of the multiple temperatures that the detection resistor TK can assume. The temperature determination unit 71 refers to this table and determines the temperature of the pressure chamber CV1 based on the detection result signal DK.

[0071] However, using the piezoelectric element Qm and the detection resistor TK together can reduce the accuracy of temperature measurement by the detection resistor TK. If the accuracy of temperature measurement is reduced, adjusting the maintenance drive signal Com by the signal adjustment unit 72 will not be able to sufficiently remove the thickened ink and air bubbles mixed in the ink from the liquid ejection head 1, increasing the likelihood of missing dots and ejection failures. Furthermore, because ejection characteristics change with temperature, if the accuracy of temperature measurement is reduced, there is a risk that the desired ejection characteristics will not be obtained even if the drive signal Com, etc. is adjusted according to the measured temperature. The inventors' experiments have revealed that the cause of the decrease in the accuracy of temperature measurement by the detection resistor TK is the diffusion of lead atoms from the piezoelectric body Qm to the detection resistor TK. If the lead atoms contained in the piezoelectric body Qm diffuse into the detection resistor TK when the piezoelectric body Qm is fired, the material of the detection resistor TK will differ from the material assumed by the developer of the liquid ejection head 1. Therefore, it is believed that the decrease in the accuracy of temperature measurement by the detection resistor TK occurs because the characteristics of the resistance value RK corresponding to the temperature of the detection resistor TK shown in the table stored in the memory circuit of the control unit 7 differ from the characteristics of the resistance value RK corresponding to the actual temperature of the detection resistor TK.

[0072] Therefore, the liquid ejection head 1 according to the first embodiment has a diffusion-preventing layer YK to prevent lead atoms contained in the piezoelectric body Qm from diffusing to the detecting resistor TK. The diffusion-preventing layer YK is provided between the piezoelectric body Qm and the detecting resistor TK. Note that another layer may be provided between the piezoelectric body Qm and the diffusion-preventing layer YK, or another layer may be provided between the diffusion-preventing layer YK and the detecting resistor TK.

[0073] In the first embodiment, the diffusion suppression layer YK is provided to cover the detection resistor TK. More specifically, the detection resistor TK contacts the diaphragm 24 in the Z1 direction, and contacts the detection resistor TK in directions other than the Z1 direction, specifically the Z2 direction, the X-axis direction, and the Y-axis direction. Therefore, in the first embodiment, the detection resistor TK does not contact the piezoelectric element Qm. The diffusion suppression layer YK also contacts the diaphragm 24. The diffusion suppression layer YK includes a suppression layer extension portion YKx1, a suppression layer extension portion YKy, and a suppression layer extension portion YKx2.

[0074] A diffusion suppression layer YK may be provided between the piezoelectric body Qm and the individual electrode Qc, or the diffusion suppression layer YK may not be provided. In the first embodiment, it is assumed that a diffusion suppression layer YK is not provided between the piezoelectric body Qm and the individual electrode Qc.

[0075] The suppression layer extension portion YKx1 extends in the X-axis direction. One end of the suppression layer extension portion YKx1 is connected to the contact hole CH1, and the other end is connected to the suppression layer extension portion YKy. The suppression layer extension portion YKx1 is provided so as to cover the resistor extension portion TKx1. The suppression layer extension portion YKy extends in the Y-axis direction. One end of the suppression layer extension portion YKy is connected to the suppression layer extension portion YKx1, and the other end is connected to the suppression layer extension portion YKx2. The suppression layer extension portion YKy is provided so as to cover the resistor extension portion TKy1, resistor extension portion TKy2, and resistor extension portion TKy3. The suppression layer extension portion YKx2 extends in the X-axis direction. One end of the suppression layer extension portion YKx2 is connected to the contact hole CH2, and the other end is connected to the suppression layer extension portion YKy. The suppression layer extension portion YKx2 is provided so as to cover the resistor extension portion TKx2.

[0076] The diffusion barrier layer YK is made of an oxide containing any one of the metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium. In this embodiment, it is assumed that the diffusion barrier layer YK is made of zirconium oxide.

[0077] 4 and 5 and the later-described FIGS. 6 and 7 illustrate the configuration of the portion of the liquid ejection head 1 corresponding to the sealed space SP1 located in the X1 direction relative to the wiring substrate 4, but the same explanation as in FIGS. 4, 5, 6, and 7 also applies to the configuration of the portion corresponding to the sealed space SP2 located in the X2 direction relative to the wiring substrate 4.

[0078] FIG. 6 is a cross-sectional view taken along line kK in FIG.

[0079] As shown in Figure 6, of the two surfaces of the vibration plate 24 whose normal direction is the Z-axis direction, a piezoelectric element PZ1, a detection resistor TK, a diffusion suppression layer YK, and a sealing substrate 25 are formed on the Z2-direction surface.

[0080] Hereinafter, of the two surfaces of the piezoelectric body Qm whose normal direction is the Z-axis direction, the surface in the Z2 direction will be referred to as surface PL1, and the surface in the Z1 direction will be referred to as surface PL2. Note that surface PL1 is an example of a "first surface," and surface PL2 is an example of a "second surface."

[0081] A common electrode Qb and a part of the individual wiring Lc are formed on a surface PL1 of the piezoelectric body Qm. Of the two surfaces of the common electrode Qb whose normal direction is the Z-axis direction, a partial wiring Lb2 that is a part of the common wiring Lb is formed on the surface in the Z2 direction.

[0082] An individual electrode Qc and a diffusion suppression layer YK are formed on the surface PL2 of the piezoelectric body Qm. The detection resistor TK is formed on the surface PL2 with the diffusion suppression layer YK interposed therebetween. The detection resistor TK is provided closer to the surface PL2 than to the surface PL1. In this embodiment, the detection resistor TK and the diffusion suppression layer YK are provided at positions overlapping with the sealed space SP when the liquid ejection head 1 is viewed in the Z1 direction. That is, in this embodiment, the detection resistor TK and the diffusion suppression layer YK are provided at positions not overlapping with the side wall WL1 of the sealing substrate 25 when the liquid ejection head 1 is viewed in the Z1 direction.

[0083] 6, the thickness HT of the detection resistor TK is thinner than the thickness HY of the diffusion-inhibiting layer YK. The thickness HY is the shortest distance from the surface PY1 of the diffusion-inhibiting layer YK facing the Z2 direction to the surface PT1 of the detection resistor TK facing the Z2 direction. Furthermore, it is preferable that the distance LX1 from the X1-direction end of the inhibition layer extension portion YKy to the X1-direction end of the resistor extension portion TKy1 and the distance LX2 from the X2-direction end of the inhibition layer extension portion YKy to the X2-direction end of the resistor extension portion TKy3 are longer than the thickness HT.

[0084] FIG. 7 is a cross-sectional view taken along line mM in FIG.

[0085] 7, the detection wiring LK1 has a wiring portion LKp1 and a contact hole CH1. Of the two surfaces of the diaphragm 24 whose normal direction is the Z-axis direction, the wiring portion LKp1, the detection resistor TK, the diffusion suppression layer YK, the piezoelectric body Qm, and the sealing substrate 25 are formed on the Z2-direction surface.

[0086] A wiring portion LKp1 and a common electrode Qb are formed on a surface PL1 of the piezoelectric body Qm. Of the two surfaces of the common electrode Qb whose normal direction is the Z-axis direction, a partial wiring Lb2, which is a part of the common wiring Lb, is formed on the surface in the Z2 direction.

[0087] A diffusion-inhibiting layer YK is formed on the surface PL2 of the piezoelectric body Qm. The sensing resistor TK is provided on the surface PL2 via the diffusion-inhibiting layer YK. The sensing resistor TK and the wiring portion LKp1 are electrically connected by a contact hole CH1 that penetrates the piezoelectric body Qm and the diffusion-inhibiting layer YK.

[0088] In this embodiment, it is assumed that the detection wiring LK2 has a configuration similar to that of the detection wiring LK1, the resistor extension portion TKx2 has a configuration similar to that of the resistor extension portion TKx1, the suppression layer extension portion YKx2 has a configuration similar to that of the suppression layer extension portion YKx1, and the partial wiring Lb3 has a configuration similar to that of the partial wiring Lb1.

[0089] 1.4. Summary of the First Embodiment As described above, the liquid ejection head 1 of this embodiment is characterized by having a pressure chamber substrate 23 in which a plurality of pressure chambers CV are provided, a piezoelectric body Qm containing lead atoms and driven to apply pressure to the ink in the plurality of pressure chambers CV, a common electrode Qb provided on surface PL1 of the two surfaces of the piezoelectric body Qm, individual electrodes Qc provided on surface PL2 of the two surfaces of the piezoelectric body Qm opposite surface PL1, individual wiring Lc and common wiring Lb electrically connected to the common electrode Qb and the individual electrodes Qc and applying a voltage to drive the piezoelectric body Qm, a detection resistor TK formed from the same material as any of the common electrode Qb, individual electrode Qc, individual wiring Lc, and common wiring Lb and used to measure the temperature of the ink in the plurality of pressure chambers CV, and a diffusion suppression layer YK provided between the detection resistor TK and the piezoelectric body Qm for suppressing the diffusion of lead atoms contained in the piezoelectric body Qm into the detection resistor TK. The diffusion-preventing layer YK provided between the detecting resistor TK and the piezoelectric element Qm prevents lead atoms from diffusing into the detecting resistor TK. Therefore, even when the piezoelectric element Qm and the detecting resistor TK are used together, the liquid ejection head 1 according to the first embodiment can improve the accuracy of temperature measurement by the detecting resistor TK compared to an embodiment that does not have the diffusion-preventing layer YK. By improving the accuracy of temperature measurement by the detecting resistor TK, it becomes more likely that thickened ink and air bubbles mixed in the ink can be sufficiently removed from the liquid ejection head 1, thereby reducing the possibility of missing dots and ejection defects. Furthermore, the ejection characteristics can be brought closer to the desired conditions.

[0090] The diffusion prevention layer YK is made of an oxide containing any one of the metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium. The lead atoms present as oxides in the piezoelectric body Qm cease to exist as oxides as the piezoelectric body Qm is fired at high temperatures, and in an embodiment without a diffusion-inhibiting layer YK, the lead atoms diffuse into the detection resistor TK. In contrast, in the first embodiment, the lead atoms diffused from the piezoelectric body Qm receive oxygen atoms from the oxides in the diffusion-inhibiting layer YK and are again stabilized as oxides in the diffusion-inhibiting layer YK. As described above, according to the first embodiment, the diffusion-inhibiting layer YK contains oxides of the above-mentioned metal atoms, thereby improving the accuracy of temperature measurement by the detection resistor TK compared to an embodiment without a diffusion-inhibiting layer YK. Furthermore, the diffusion-suppressing layer YK provided between the detecting resistor TK and the piezoelectric element Qm makes it difficult for the heat of the detecting resistor TK to be transmitted to the outside, so the temperature of the detecting resistor TK becomes closer to the temperature of the ink in the pressure chamber CV compared to an embodiment that does not have the diffusion-suppressing layer YK. Therefore, the liquid ejection head 1 according to the first embodiment can improve the accuracy of temperature measurement by the detecting resistor TK compared to an embodiment that does not have the diffusion-suppressing layer YK.

[0091] The piezoelectric element further includes a vibration plate 24 that is disposed closer to the surface PL2 of the piezoelectric element Qm than to the surface PL1 of the piezoelectric element Qm and vibrates when the piezoelectric element Qm is driven, and the common electrode Qb is disposed in common to the multiple pressure chambers CV, and the individual electrodes Qc are disposed individually to the multiple pressure chambers CV. Even in a configuration in which the common electrode Qb is a so-called upper electrode and the individual electrode Qc is a so-called lower electrode, the accuracy of temperature measurement by the detection resistor TK can be improved. Therefore, according to the first embodiment, the degree of freedom in the configuration of the piezoelectric element PZ can be improved.

[0092] The detection resistor TK is also characterized by being made of the same material as the individual electrodes Qc. In this embodiment, the detection resistor TK and the individual electrodes Qc are made of platinum. The liquid ejection head 1 of the first embodiment makes it possible to suppress an increase in manufacturing costs of the liquid ejection head 1 due to the provision of the detection resistor TK, compared to an embodiment in which the detection resistor TK and the individual electrode Qc are formed from different materials.

[0093] Furthermore, the detection resistor TK is characterized in that it is provided closer to the surface PL2 of the piezoelectric body Qm than to the surface PL1. That is, in the liquid ejection head 1 according to the first embodiment, the detection resistor TK and the individual electrodes Qc are provided in the same layer, so that the detection resistor TK and the individual electrodes Qc can be patterned simultaneously. Therefore, according to the liquid ejection head 1 according to the first embodiment, it is possible to suppress an increase in the manufacturing cost of the liquid ejection head 1 due to the provision of the detection resistor TK, compared to an embodiment in which the detection resistor TK and the individual electrodes Qc are provided in different layers.

[0094] The diaphragm 24 includes an insulating layer made of zirconium oxide, and the diffusion-preventing layer YK also includes zirconium oxide. That is, the insulating layer of the diaphragm 24 and the diffusion-preventing layer YK contain the same molecules. Generally, when two objects contain the same molecules, the interfacial adhesive strength tends to be higher than when they do not. Therefore, peeling of the diffusion-preventing layer YK from the diaphragm 24 can be suppressed compared to when the diffusion-preventing layer YK does not contain zirconium oxide. When the diffusion-preventing layer YK peels off from the diaphragm 24, the sensing resistor TK may also peel off from the diaphragm 24 along with the diffusion-preventing layer YK. Peeling of the sensing resistor TK from the diaphragm 24 reduces the heat transfer from the diaphragm 24 to the diffusion-preventing layer YK. Therefore, when the sensing resistor TK peels off from the diaphragm 24, the temperature of the sensing resistor TK deviates from the temperature of the ink in the pressure chamber CV compared to when the sensing resistor TK is bonded to the diaphragm 24. Therefore, the liquid ejection head 1 according to the first embodiment can improve the accuracy of temperature measurement by the sensing resistor TK compared to when the diffusion-preventing layer YK does not contain zirconium oxide.

[0095] The detection resistor TK is characterized by containing platinum. Platinum is preferably used as the material for the electrodes, and in the first embodiment, the material of the individual electrodes Qc is also platinum. Therefore, by including platinum in the detection resistor TK, it is possible to suppress an increase in the manufacturing cost of the liquid ejection head 1 due to the provision of the detection resistor TK, compared to an embodiment in which the detection resistor TK and the individual electrodes Qc are formed of different materials.

[0096] Furthermore, the thickness HT of the detection resistor TK is thinner than the thickness HY of the diffusion-preventing layer YK. As the thickness of the diffusion-preventing layer YK increases, the diffusion of lead atoms into the detection resistor TK can be suppressed. Furthermore, since the temperature determination unit 71 determines the temperature based on the resistance value RK, as the resistance value RK increases, the noise value relative to the resistance value RK decreases, thereby improving the accuracy of temperature measurement by the detection resistor TK. Generally, the resistance value of an electric wire can be increased by increasing the length of the electric wire and reducing the cross-sectional area of ​​the electric wire. Therefore, as the thickness of the detection resistor TK decreases, the accuracy of temperature measurement by the detection resistor TK can be further improved. Therefore, the liquid ejection head 1 according to the first embodiment can improve the accuracy of temperature measurement by the detection resistor TK compared to an embodiment in which the thickness HT of the detection resistor TK is thicker than the thickness HY of the diffusion-preventing layer YK. In addition, the liquid ejection head 1 according to the first embodiment has the detection resistor TK bent on the XY plane as shown in FIG. 4, thereby increasing the length of the detection resistor TK and improving the accuracy of temperature measurement by the detection resistor TK.

[0097] Another feature is that no diffusion suppression layer YK is provided between the piezoelectric body Qm and the individual electrode Qc. When a diffusion-suppressing layer YK is provided between the piezoelectric body Qm and the individual electrode Qc, the characteristics of the current flow through the piezoelectric element PZ from the individual electrode Qc to the common electrode Qb via the piezoelectric body Qm may change, compared to an embodiment in which a diffusion-suppressing layer YK is not provided between the piezoelectric body Qm and the individual electrode Qc. Therefore, even if the piezoelectric element PZ is driven by the drive signal Com, there is a higher possibility of ejection defects occurring, compared to an embodiment in which a diffusion-suppressing layer YK is not provided between the piezoelectric body Qm and the individual electrode Qc. Therefore, the liquid ejection head 1 according to the first embodiment can reduce the possibility of ejection defects occurring, compared to an embodiment in which a diffusion-suppressing layer YK is provided between the piezoelectric body Qm and the individual electrode Qc.

[0098] The liquid ejection device 100 according to the first embodiment also includes the liquid ejection head 1 and a control unit 7 that controls the ejection operation from the liquid ejection head 1. The liquid ejection device 100 according to the first embodiment can improve the accuracy of temperature measurement by the detection resistor TK compared to an embodiment that does not have the diffusion suppression layer YK.

[0099] 2. Second embodiment The diffusion prevention layer YK in the first embodiment is made of an oxide containing any one of metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium. On the other hand, the diffusion prevention layer YK in the second embodiment differs from the first embodiment in that it is made of any one of metal atoms of iridium, ruthenium, rhodium, and osmium. The second embodiment will be described below.

[0100] Fig. 8 is a diagram illustrating a liquid ejection head 1-A according to a second embodiment. Fig. 8 shows an enlarged view of the vicinity of an extended portion YKy-A of the diffusion-suppressing layer YK-A according to the second embodiment in a cross section of the liquid ejection head 1-A taken along line kK in Fig. 4. The liquid ejection head 1-A differs from the liquid ejection head 1 in that it has a diffusion-suppressing layer YK-A instead of the diffusion-suppressing layer YK. The diffusion-suppressing layer YK-A is composed of metal atoms of any one of iridium, ruthenium, rhodium, and osmium.

[0101] The diffusion-preventing layer YK-A prevents lead atoms from diffusing into the detecting resistor TK. Experiments conducted by the inventors have shown that when the diffusion-preventing layer YK-A is made of iridium, the diffusion of lead atoms into the detecting resistor TK is prevented. The thicker the diffusion-preventing layer YK-A, the more effectively the diffusion of lead atoms into the detecting resistor TK is prevented. Furthermore, the diffusion-preventing layer YK-A reduces the transfer of heat from the detecting resistor TK to the outside, so the temperature of the detecting resistor TK is closer to the temperature of the ink in the pressure chamber CV than in an embodiment without the diffusion-preventing layer YK. Therefore, the liquid ejection head 1-A according to the second embodiment can improve the accuracy of temperature measurement by the detecting resistor TK compared to an embodiment without the diffusion-preventing layer YK.

[0102] 3. Third embodiment The diffusion suppression layer YK-B in the third embodiment differs from that in the first embodiment in that it includes a metal layer S1 made of any one of iridium, ruthenium, rhodium, and osmium atoms, and an oxide layer S2 made of an oxide containing any one of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium atoms. The third embodiment will be described below.

[0103] Fig. 9 is a diagram illustrating a liquid ejection head 1-B according to a third embodiment. Fig. 9 shows an enlarged view of the vicinity of an extended portion YKy-B of the diffusion-suppressing layer YK-B according to the third embodiment in a cross section of the liquid ejection head 1-B taken along line kK in Fig. 4. The liquid ejection head 1-B differs from the liquid ejection head 1 in that it has a diffusion-suppressing layer YK-B instead of the diffusion-suppressing layer YK.

[0104] The diffusion prevention layer YK-B has a metal layer S1 and an oxide layer S2. The metal atoms contained in the metal layer S1 and the metal atoms contained in the oxide layer S2 may be the same type of element or different types of elements. The diffusion prevention layer YK-B may also include layers other than the metal layer S1 and the oxide layer S2. The metal layer S1 is an example of a "first layer." The oxide layer S2 is an example of a "second layer."

[0105] 9, the detection resistor TK, oxide layer S2, metal layer S1, and piezoelectric body Qm are stacked in this order in the Z2 direction. In other words, the oxide layer S2 is provided between the detection resistor TK and the metal layer S1. However, the detection resistor TK, metal layer S1, oxide layer S2, and piezoelectric body Qm may also be stacked in this order in the Z2 direction. The following description is based on the assumption that the detection resistor TK, oxide layer S2, metal layer S1, and piezoelectric body Qm are stacked in this order in the Z2 direction.

[0106] The liquid ejection head 1-B according to the third embodiment can improve the accuracy of temperature measurement by the detection resistor TK compared to a mode that does not have the diffusion suppression layer YK.

[0107] In addition, the oxide layer S2 is provided between the detection resistor TK and the metal layer S1. By providing the oxide layer S2 between the detection resistor TK and the metal layer S1, heat from the detection resistor TK is less likely to be transmitted to the metal layer S1, and so the temperature of the detection resistor TK becomes closer to the temperature of the ink in the pressure chamber CV compared to an embodiment in which the metal layer S1 is provided between the detection resistor TK and the oxide layer S2. Therefore, the liquid ejection head 1-B according to the third embodiment can improve the accuracy of temperature measurement by the detection resistor TK compared to an embodiment that does not have the diffusion suppression layer YK.

[0108] As described above, in the first, second, and third embodiments, the diffusion-preventing layer YK contains one of the metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium. As can be seen from the third embodiment, the diffusion-preventing layer YK may contain one or more types of metal atoms selected from zirconium, hafnium, iridium, ruthenium, rhodium, and osmium. Because the diffusion-inhibiting layer YK contains any of the metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium, the liquid ejection head 1 of any of the first, second, and third embodiments can improve the accuracy of temperature measurement by the detection resistor TK compared to a configuration that does not have the diffusion-inhibiting layer YK.

[0109] 4. Fourth embodiment The fourth embodiment differs from the first embodiment in that an absorption layer KS is provided between the diffusion suppression layer YK of any one of the first to third embodiments and the piezoelectric body Qm. The fourth embodiment will be described below.

[0110] Fig. 10 is a diagram illustrating a liquid ejection head 1-C according to a fourth embodiment. Fig. 10 shows an enlarged view of the vicinity of the diffusion-suppressing layer extending portion YKy of the diffusion-suppressing layer YK according to the fourth embodiment in a cross section of the liquid ejection head 1-C taken along line kK in Fig. 4. The liquid ejection head 1-C differs from the liquid ejection head 1 in that it has an absorption layer KS.

[0111] As shown in FIG. 10, the absorption layer KS is provided between the diffusion prevention layer YK and the piezoelectric body Qm. The absorption layer KS absorbs lead atoms. The absorption layer KS is made of, for example, titanium. Note that another layer may be provided between the diffusion prevention layer YK and the absorption layer KS, or another layer may be provided between the absorption layer KS and the piezoelectric body Qm. Note that the absorption layer KS corresponds to a "layer made of titanium."

[0112] As described above, the liquid ejection head 1-C according to the fourth embodiment is characterized by further having an absorption layer KS made of titanium provided between the diffusion suppression layer YK and the piezoelectric body Qm. By absorbing lead atoms in the absorbing layer KS, the amount of lead atoms diffusing from the piezoelectric body Qm to the diffusion suppression layer YK can be reduced compared to an embodiment without the absorbing layer KS. Therefore, in the fourth embodiment, the amount of lead atoms diffusing to the detecting resistor TK can be reduced compared to an embodiment without the absorbing layer KS. As a result, the liquid ejection head 1-C according to the fourth embodiment can improve the accuracy of temperature measurement by the detecting resistor TK compared to an embodiment without the absorbing layer KS.

[0113] 5. Variations The above-described embodiments can be modified in various ways. Specific modifications are exemplified below. Two or more embodiments selected from the following examples can be combined as long as they are not mutually contradictory.

[0114] 5.1. First Modification In each of the above-described embodiments, the common electrode Qb is provided on the surface PL1 of the piezoelectric body Qm, and the individual electrode Qc is provided on the surface PL2 of the piezoelectric body Qm, but the common electrode Qb may be provided on the surface PL2, and the individual electrode Qc may be provided on the surface PL1.

[0115] Fig. 11 is a plan view of the liquid ejection head 1-D according to the first modified example when viewed in the Z1 direction. Fig. 12 is a cross-sectional view taken along line jJ in Fig. 11. The liquid ejection head 1-D differs from the liquid ejection head 1 according to the first embodiment in that it has a common electrode Qb-D instead of the common electrode Qb, a common wiring Lb-D instead of the common wiring Lb, a plurality of individual electrodes Qc-D instead of the plurality of individual electrodes Qc, and a plurality of individual wiring Lc-D instead of the plurality of individual wiring Lc.

[0116] The common wiring Lb-D is a wiring that extends in the X-axis direction. One end of the common wiring Lb-D is electrically connected to a wiring provided on the wiring substrate 4, and the other end is connected to the common electrode Qb-D. As shown in FIG. 12, the common electrode Qb-D is provided on the surface PL2 of the piezoelectric body Qm. In the first modified example, the common electrode Qb-D is a so-called lower electrode. Note that in the first modified example, the common electrode Qb-D is an example of a "second electrode."

[0117] The individual wiring Lc-D is a wiring that extends in the X-axis direction when the liquid ejection head 1-D is viewed in a plane in the Z1 direction. One end of the individual wiring Lc-D is electrically connected to a wiring provided on the wiring substrate 4. The individual electrode Qc-D is provided in an area that overlaps with the individual wiring Lc-D when the liquid ejection head 1-D is viewed in a plane in the Z1 direction. The individual electrode Qc-D is connected to the individual wiring Lc-D. As shown in FIG. 12, the individual electrode Qc-D is provided on the surface PL1 of the piezoelectric body Qm. In the first modified example, the individual electrode Qc-D is a so-called upper electrode. Note that in the first modified example, the individual electrode Qc-D is an example of a "first electrode."

[0118] As described above, the liquid ejection head 1-D of the first modified example is characterized in that it is arranged closer to the surface PL2 of the piezoelectric body Qm than to the surface PL1, and further has a vibration plate 24 that vibrates when the piezoelectric body Qm is driven, and that individual electrodes Qc-D are arranged individually for the multiple pressure chambers CV, and that a common electrode Lb-D is arranged in common for the multiple pressure chambers CV. According to the first embodiment, even in an embodiment in which the common electrode Qb-D is a so-called lower electrode and the individual electrode Qc-D is a so-called upper electrode, the accuracy of temperature measurement by the detection resistor TK can be improved. Therefore, according to the first modification, the degree of freedom in the configuration of the piezoelectric element PZ can be improved.

[0119] 5.2. Second Variant In each of the above-described embodiments, the diffusion suppression layer YK is in contact with the diaphragm 24 in the Z1 direction and in contact with the detection resistor TK in directions other than the Z1 direction, but this is not limiting.

[0120] Fig. 13 is a diagram illustrating a liquid ejection head 1-E according to a second modified example. Fig. 13 shows an enlarged view of the vicinity of the diffusion-suppressing layer YK-E in the second modified example, in a cross section of the liquid ejection head 1-E taken along line kK in Fig. 4. The liquid ejection head 1-E differs from the liquid ejection head 1 according to the first embodiment in that it has a diffusion-suppressing layer YK-E instead of the diffusion-suppressing layer YK.

[0121] When the liquid ejection head 1 is viewed in a plane in the Z1 direction, the outer shape of the diffusion-suppressing layer YK-E substantially matches the outer shape of the detection resistor TK. In the second modified example, the detection resistor TK contacts the vibration plate 24 in the Z1 direction, the diffusion-suppressing layer YK-E in the Z2 direction, and the piezoelectric element Qm in the X-axis direction and the Y-axis direction.

[0122] According to the second modification, the diffusion-preventing layer YK-E prevents lead atoms that migrate from the piezoelectric body Qm in the Z1 direction from diffusing into the detecting resistor TK. Therefore, the liquid ejection head 1-E according to the second modification can improve the accuracy of temperature measurement by the detecting resistor TK compared to an embodiment that does not have the diffusion-preventing layer YK-E. However, in the second modification, the diffusion-preventing layer YK-E cannot prevent lead atoms that migrate from the piezoelectric body Qm in a direction perpendicular to the Z-axis direction, such as the X-axis or Y-axis direction, from diffusing into the detecting resistor TK. Therefore, the liquid ejection head 1 according to the first embodiment can improve the accuracy of temperature measurement by the detecting resistor TK compared to the liquid ejection head 1-E according to the second modification.

[0123] 5.3.Third Modification In the above-described embodiments, the detection resistor TK is provided closer to the surface PL2 of the piezoelectric body Qm than to the surface PL1, but it may be provided closer to the surface PL1 of the piezoelectric body Qm than to the surface PL2.

[0124] Fig. 14 is a diagram illustrating a liquid ejection head 1-F according to a third modified example. Fig. 14 shows a cross section of the liquid ejection head 1-F taken along line kK in Fig. 4. The liquid ejection head 1-F differs from the liquid ejection head 1 according to the first embodiment in that it has a detection resistor TK-F instead of the detection resistor TK, and a diffusion suppression layer YK-F instead of the diffusion suppression layer YK.

[0125] As shown in Fig. 14, the diffusion suppression layer YK-F is provided on the surface PL1 of the piezoelectric body Qm. The detection resistor TK-F is provided on the surface PY1-F of the diffusion suppression layer YK-F facing the Z2 direction. In other words, the detection resistor TK-F is formed with the diffusion suppression layer YK-F interposed between them and the surface PL1. The detection resistor TK-F is provided closer to the surface PL1 than to the surface PL2. In the third modification, it is assumed that the detection resistor TK-F is made of the same material as the common electrode Qb.

[0126] As described above, the third modified example is characterized in that the detection resistor TK-F is made of the same material as the common electrode Qb. The liquid ejection head 1 of the third modified example makes it possible to suppress the increase in manufacturing costs of the liquid ejection head 1-F due to the provision of the detection resistor TK-F, compared to an embodiment in which the detection resistor TK-F and the common electrode Qb are formed of different materials.

[0127] Furthermore, the third modification is characterized in that the detection resistor TK-F is provided closer to the surface PL1 than to the surface PL2 of the piezoelectric body Qm. That is, in the liquid ejection head 1-F according to the third modification, the detection resistor TK-F and the common electrode Qb are provided in substantially the same layer, so that the detection resistor TK-F and the common electrode Qb can be patterned simultaneously. Therefore, with the liquid ejection head 1-F according to the third modification, it is possible to suppress an increase in manufacturing costs of the liquid ejection head 1-F due to the provision of the detection resistor TK-F, compared to an embodiment in which the detection resistor TK-F and the common electrode Qb are provided in different layers.

[0128] 5.4. Fourth Variant In the above-described embodiments, it has been described that the diffusion-preventing layer YK is not provided between the piezoelectric body Qm and the individual electrode Qc, but the diffusion-preventing layer YK may be provided between the piezoelectric body Qm and the individual electrode Qc.

[0129] Fig. 15 is a diagram illustrating a liquid ejection head 1-G according to a fourth modified example. Fig. 15 shows a cross section of the liquid ejection head 1-G taken along line kK in Fig. 4. The liquid ejection head 1-G differs from the liquid ejection head 1 according to the first embodiment in that it has a diffusion-suppressing layer YK-G instead of the diffusion-suppressing layer YK. Furthermore, the fourth modified example is premised on the fact that the piezoelectric body Qm contains metal atoms capable of forming the diffusion-suppressing layer YK, specifically zirconium atoms.

[0130] The diffusion-preventing layer YK-G is provided not only between the detection resistor TK and the piezoelectric element Qm, but also between the individual electrode Qc and the piezoelectric element Qm. Furthermore, in Fig. 15, the diffusion-preventing layer YK-G is also provided in an area between the surface PL2 of the piezoelectric element Qm and the vibration plate 24, where no individual electrode Qc is present when the liquid ejection head 1-G is viewed in a plan view in the Z1 direction. For example, the portion of the diffusion-preventing layer YK-G between the piezoelectric element Qm and the individual electrode Qc is formed when the piezoelectric element Qm is formed by high-temperature firing, whereby zirconium atoms contained in the piezoelectric element Qm precipitate to produce zirconium oxide.

[0131] As shown in Figure 15, the thickness HY of the portion of the diffusion-preventing layer YK-G between the detection resistor TK and the piezoelectric element Qm is thicker than the thickness HY2 of the portion of the diffusion-preventing layer YK-G between the piezoelectric element Qm and the individual electrode Qc. According to the fourth modification, the diffusion-suppressing layer YK-G is generated by firing the piezoelectric body Qm at a high temperature, making it easier to manufacture than the liquid ejection head 1 according to the first embodiment. Furthermore, because the thickness HY is greater than the thickness HY2, changes in the characteristics of the electrical conduction of the piezoelectric element PZ from the individual electrode Qc to the common electrode Qb via the piezoelectric body Qm can be suppressed compared to an embodiment in which the thickness HY2 is greater than the thickness HY. Therefore, according to the liquid ejection head 1-G according to the fourth modification, the possibility of ejection defects occurring can be reduced compared to an embodiment in which the thickness HY2 is greater than the thickness HY.

[0132] 5.5. Fifth Variant In each of the above-described embodiments, the detection resistor TK corresponding to the pressure chamber CV2, i.e., the detection resistor TK provided in the X2 direction from the wiring board 4, is provided separately from the detection resistor TK corresponding to the pressure chamber CV1, i.e., the detection resistor TK provided in the X1 direction from the wiring board 4, but this is not limited to this. For example, the detection resistor TK corresponding to the pressure chamber CV1 and the detection resistor TK corresponding to the pressure chamber CV2 may be provided integrally.

[0133] FIG. 16 is a plan view of the liquid ejection head 1-H according to the fifth modified example, when viewed in plan in the Z1 direction.

[0134] As shown in Figure 16, the liquid ejection head 1-H differs from the liquid ejection head 1 of the first embodiment in that it has one detection resistor TK-H instead of two detection resistors TK, namely, the detection resistor TK corresponding to pressure chamber CV1 and the detection resistor TK corresponding to pressure chamber CV2, and has one diffusion suppression layer YK-H instead of two diffusion suppression layers YK corresponding to the two detection resistors TK.

[0135] The detection resistor TK-H differs from the detection resistor TK in that, instead of the resistor extension portion TKx2, it has a resistor extension portion TKx-H1 arranged to intersect with the wiring board 4, and resistor extension portions TKy4, TKy5, TKy6, and TKx-H2 positioned in the X2 direction from the wiring board 4.

[0136] When the liquid ejection head 1-H is viewed in the Z1 direction, the resistor extension portion TKx-H1 is provided so as to extend in the X-axis direction, intersecting with the wiring board 4. One end of the resistor extension portion TKx-H1 is connected to the resistor extension portion TKy3, and the other end is connected to the resistor extension portion TKy4. The resistor extension portion TKy4 is provided so as to be symmetrical to the resistor extension portion TKy3 with respect to the wiring board 4. One end of the resistor extension portion TKy4 is connected to the resistor extension portion TKx-H1, and the other end is connected to the resistor extension portion TKy5. The resistor extension portion TKy5 is provided so as to be symmetrical to the resistor extension portion TKy2 with respect to the wiring board 4. One end of the resistor extension portion TKy5 is connected to the resistor extension portion TKy4, and the other end is connected to the resistor extension portion TKy6. The resistor extension portion TKy6 is provided so as to be symmetrical to the resistor extension portion TKy1 with respect to the wiring board 4. One end of the resistor extension portion TKy6 is connected to the resistor extension portion TKy5, and the other end is connected to the resistor extension portion TKx-H2. The resistor extension portion TKx-H2 is provided so as to be symmetrical to the resistor extension portion TKx1 with respect to the wiring substrate 4. One end of the resistor extension portion TKx-H2 is connected to the resistor extension portion TKy6, and the other end is connected to the contact hole CH-H of the detection wiring LK-H. The detection wiring LK-H is arranged so as to be line-symmetrical with the detection wiring LK1 with the wiring board 4 as the axis of symmetry, and is electrically connected to wiring on the wiring board 4 that is set to ground potential. The contact hole CH-H is also arranged so as to be line-symmetrical with the contact hole CH1 with the wiring board 4 as the axis of symmetry.

[0137] In this modification, a current I0 supplied to the detection wiring LK1 flows from the detection wiring LK1 through resistor extension portion TKx1, resistor extension portion TKy1, resistor extension portion TKy2, resistor extension portion TKy3, resistor extension portion TKx-H1, resistor extension portion TKy4, resistor extension portion TKy5, resistor extension portion TKy6, resistor extension portion TKx-H2, and the detection wiring LK-H to a wiring on the wiring board 4 to which the detection wiring LK-H is electrically connected. Then, a voltage detection circuit 82 according to this modification detects a voltage VK-H applied across the detection resistor TK-H.

[0138] Furthermore, the temperature specifying section 71 according to this modification specifies the temperature of the ink in the pressure chamber CV based on the voltage VK-H detected by the voltage detection circuit .

[0139] The diffusion suppression layer YK-H differs from the diffusion suppression layer YK in that, instead of the suppression layer extension portion YKx2, it has an suppression layer extension portion YKx-H1 arranged to intersect with the wiring substrate 4, an suppression layer extension portion YKy-H positioned in the X2 direction from the wiring substrate 4, and an suppression layer extension portion YKx-H2.

[0140] When the liquid ejection head 1-H is viewed in the Z1 direction, the suppression layer extension portion YKx-H1 is provided so as to extend in the X-axis direction, intersecting with the wiring substrate 4. One end of the suppression layer extension portion YKx-H1 is connected to the suppression layer extension portion YKy, and the other end is connected to the suppression layer extension portion YKy-H. The suppression layer extension portion YKx-H1 is provided so as to cover the resistor extension portion TKx-H1. The suppression layer extension portion YKy-H is provided so as to be symmetrical to the suppression layer extension portion YKy with the wiring substrate 4 as the axis of symmetry. One end of the suppression layer extension portion YKy-H is connected to the suppression layer extension portion YKx-H1, and the other end is connected to the suppression layer extension portion YKx-H2. The suppression layer extension portion YKy-H is provided so as to cover the resistor extension portion TKy4, resistor extension portion TKy5, and resistor extension portion TKy6. The suppression layer extension portion YKx-H2 is provided so as to be symmetrical to the suppression layer extension portion YKx1 with respect to the wiring substrate 4. One end of the suppression layer extension portion YKx-H2 is connected to the suppression layer extension portion YKy-H and to the contact hole CH-H.

[0141] 5.6. Sixth Variant In the above-described embodiments, the liquid ejection device 100 is a serial type in which the storage case 921 is reciprocated in the X-axis direction, but the present invention is not limited to such embodiments. The liquid ejection device may be a line type in which multiple nozzles N are distributed across the entire width of the medium PP.

[0142] 5.7. Seventh Variant The liquid ejection apparatuses of the above-described embodiments can be employed in various devices, such as facsimile machines and copiers, as well as devices dedicated to printing. However, the use of the liquid ejection apparatus of the present invention is not limited to printing. For example, a liquid ejection apparatus that ejects a solution of a color material is used as a manufacturing apparatus for forming color filters for liquid crystal display devices. Furthermore, a liquid ejection apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes for wiring substrates. [Explanation of symbols]

[0143] 1...liquid ejection head, 4...wiring substrate, 7...control unit, 8...detection device, 21...nozzle substrate, 22...communicating plate, 23...pressure chamber substrate, 24...vibration plate, 25...sealing substrate, 26...flow path forming substrate, 40...integrated circuit, 71...temperature specifying unit, 72...signal adjusting unit, 81...current supply circuit, 82...voltage detection circuit, Lb...common wiring, Lc...individual wiring, PL1, PL2...surface, PZ1, PZ2...piezoelectric element, Qb...common electrode, Qc...individual electrode, Qm...piezoelectric body, S1...metal layer, S2...oxide layer, TK...detection resistor, YK...diffusion suppression layer.

Claims

1. a pressure chamber substrate provided with a plurality of pressure chambers; a piezoelectric body including lead atoms, the piezoelectric body being driven to apply pressure to the liquid in the plurality of pressure chambers; a first electrode provided on a first surface of the two surfaces of the piezoelectric body; a second electrode provided on a second surface of the piezoelectric body opposite to the first surface; a driving wiring electrically connected to the first electrode and the second electrode, for applying a voltage to drive the piezoelectric body; a resistor formed of the same material as any one of the first electrode, the second electrode, and the drive wiring, for measuring the temperature of the liquid in the plurality of pressure chambers; a diffusion suppression layer provided between the resistor and the piezoelectric body to suppress diffusion of lead atoms contained in the piezoelectric body into the resistor; A liquid ejection head comprising:

2. 2. The liquid ejection head according to claim 1, wherein the diffusion prevention layer contains any one of metal atoms of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium.

3. 3. The liquid ejection head according to claim 2, wherein the diffusion prevention layer is made of an oxide containing the metal atoms.

4. 3. The liquid ejection head according to claim 2, wherein the diffusion suppression layer includes a first layer made of metal atoms of one of iridium, ruthenium, rhodium, and osmium, and a second layer made of an oxide containing metal atoms of one of zirconium, hafnium, iridium, ruthenium, rhodium, and osmium.

5. 5. The liquid ejection head according to claim 4, wherein the second layer is provided between the resistor and the first layer.

6. 6. The liquid ejection head according to claim 1, further comprising a layer made of titanium provided between the diffusion suppression layer and the piezoelectric body.

7. a vibration plate that is provided closer to the second surface of the piezoelectric body than to the first surface and vibrates when the piezoelectric body is driven; the first electrode is provided in common to the plurality of pressure chambers, 7. The liquid ejection head according to claim 1, wherein the second electrodes are individually provided for the plurality of pressure chambers.

8. a vibration plate that is provided closer to the second surface of the piezoelectric body than to the first surface and vibrates when the piezoelectric body is driven; the first electrodes are provided individually for the plurality of pressure chambers, 7. The liquid ejection head according to claim 1, wherein the second electrode is provided in common to the plurality of pressure chambers.

9. 9. The liquid ejection head according to claim 7, wherein the resistor is made of the same material as the second electrode.

10. The liquid ejection head according to claim 9, wherein the resistor is provided closer to the second surface of the piezoelectric element than to the first surface.

11. the diaphragm includes an insulating layer made of zirconium oxide; 11. The liquid ejection head according to claim 9, wherein the diffusion-preventing layer contains zirconium oxide.

12. 9. The liquid ejection head according to claim 7, wherein the resistor is made of the same material as the first electrode.

13. 13. The liquid ejection head according to claim 12, wherein the resistor is provided closer to the first surface of the piezoelectric element than to the second surface of the piezoelectric element.

14. 14. The liquid ejection head according to claim 1, wherein the resistor contains platinum.

15. 15. The liquid ejection head according to claim 1, wherein the resistor has a thickness smaller than that of the diffusion suppressing layer.

16. 16. The liquid ejection head according to claim 1, wherein the diffusion suppression layer is not provided between the piezoelectric body and the second electrode.

17. the diffusion suppression layer is also provided between the piezoelectric body and the second electrode, A liquid ejection head described in any one of claims 1 to 15, characterized in that the thickness of the portion of the diffusion-inhibiting layer between the resistor and the piezoelectric element is thicker than the thickness of the portion of the diffusion-inhibiting layer between the piezoelectric element and the second electrode.

18. A liquid ejection head according to any one of claims 1 to 17; a control unit for controlling a discharge operation from the liquid discharge head; A liquid ejection device comprising:

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