Liquid discharge head and liquid discharge device

Abstract

To solve the problem of a conventional technique that due to a structure where an auxiliary electrode is stacked on a common electrode Qb disposed in a liquid discharge head 1, the thickness of the liquid discharge head 1 becomes larger compared to an aspect where the liquid discharge head 1 is not provided with an auxiliary electrode.SOLUTION: A liquid head 1 includes: a nozzle substrate 21 provided with a nozzle N for discharging liquid; a pressure chamber substrate 23 provided with a plurality of pressure chambers CV for applying pressure to liquid; a piezoelectric element PZ comprising a piezoelectric substance Qm, an individual electrode Qc individually disposed in the plurality of pressure chambers CV, and a common electrode Qb disposed in the plurality of pressure chambers CV in common; and a wiring substrate 4 provided with an individual wiring Wc for applying a voltage to the individual electrode Qc, a common wiring Wb for applying a voltage to the common electrode Qb, and an auxiliary wiring Aw electrically connected to the common wiring Wb to make the common electrode Wb low resistant.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and a liquid ejection device.

Background Art

[0002] In a liquid ejection head including a piezoelectric element composed of a plurality of pressure chambers for applying pressure to a liquid, individual electrodes provided individually for the plurality of pressure chambers, a common electrode provided commonly for the plurality of pressure chambers, and a piezoelectric body, a technique for reducing the resistance of the common electrode is known. For example, Patent Document 1 discloses a technique for reducing the resistance of a common electrode by laminating an auxiliary electrode on the common electrode within a recess of a protective portion in a liquid ejection head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the conventional technique, even if an attempt is made to increase the height of the common electrode for resistance reduction, it can only be increased up to the height range of the recess. Therefore, there is a possibility that sufficient resistance reduction cannot be achieved. If the protective portion itself is made thicker and the recess is also made thicker, there is a margin in the height range, so resistance reduction is possible, but there is a problem that the thickness of the liquid ejection head increases accordingly.

Means for Solving the Problems

[0005] A liquid ejection head according to an aspect of the present invention includes a nozzle substrate provided with nozzles for ejecting liquid, a pressure chamber substrate provided with a plurality of pressure chambers for applying pressure to the liquid, a piezoelectric body, individual electrodes provided individually in the plurality of pressure chambers, a common electrode provided commonly in the plurality of pressure chambers, a piezoelectric element composed of these, individual wirings for applying a voltage to the individual electrodes, a common wiring for applying a voltage to the common electrode, and a wiring substrate provided with an auxiliary wiring that is electrically connected to the common wiring and reduces the resistance of the common electrode.

[0006] A liquid ejection device according to an aspect of the present invention includes the above-described liquid ejection head and a control device that controls the ejection operation from the liquid ejection head.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0008] 1: First Embodiment Hereinafter, with reference to FIGS. 1 to 8, the liquid ejection device 100 according to the first embodiment will be described.

[0009] 1-1: Overview of Liquid Ejection Device FIG. 1 is an explanatory diagram showing the liquid ejection device 100 according to the present embodiment.

[0010] 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 be used as the medium PP.

[0011] The liquid ejection device 100 includes a liquid container 93 for storing ink. As the liquid container 93, for example, a cartridge detachable from the liquid ejection device 100, a bag-shaped ink pack formed of a flexible film, or an ink tank capable of replenishing ink can be adopted. A plurality of types of inks with different colors are stored in the liquid container 93.

[0012] The liquid ejection device 100 includes a plurality of liquid ejection heads 1, a control device 7, a conveyance mechanism 91, a movement mechanism 92, and a supply mechanism 94.

[0013] The control device 7 includes a processing circuit such as a CPU or an 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.

[0014] The conveying mechanism 91 conveys the medium PP in the Y1 direction along the Y-axis under the control of the control device 7. Hereinafter, the Y1 direction and the Y2 direction opposite to the Y1 direction are collectively referred to as the Y-axis direction. Further, hereinafter, the X1 direction along the X-axis intersecting the Y-axis and the X2 direction opposite to the X1 direction are collectively referred to as the X-axis direction. Further, hereinafter, the Z1 direction along the Z-axis intersecting the X-axis and the Y-axis and the Z2 direction opposite to the Z1 direction are collectively referred to as the Z-axis direction. In the present embodiment, as an example, the case where the X-axis, the Y-axis, and the Z-axis are orthogonal to each other will be assumed and described. However, the present invention is not limited to such a mode. The X-axis, the Y-axis, and the Z-axis only need to intersect each other.

[0015] The moving mechanism 92 reciprocates the plurality of liquid ejection heads 1 in the X1 direction and the X2 direction under the control of the control device 7. The moving 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 head 1.

[0016] The supply mechanism 94 supplies the ink stored in the liquid container 93 to the liquid ejection head 1 under the control of the control device 7. Note that the supply mechanism 94 may supply the ink stored in the liquid container 93 to the liquid ejection head 1, collect the ink stored in the liquid ejection head 1, and reflux the collected ink to the liquid ejection head 1 under the control of the control device 7.

[0017] The control device 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. Then, the liquid ejection head 1 is driven by the drive signal Com under the control of the control signal SI, and ejects ink in the Z1 direction from some or all of the plurality of nozzles N provided in the liquid ejection head 1. That is, the liquid ejection head 1 ejects ink from some or all of the plurality of nozzles N in conjunction with the conveyance of the medium PP by the conveyance mechanism 91 and the reciprocating movement of the liquid ejection head 1 by the movement mechanism 92, and lands the ejected ink on the surface of the medium PP, thereby forming a desired image on the surface of the medium PP. Note that the nozzles N will be described later with reference to FIGS. 2 and 3.

[0018] 1-2: Outline of Liquid Ejection Head Hereinafter, the outline of the liquid ejection head 1 will be described with reference to FIGS. 2 and 3.

[0019] 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.

[0020] As shown in FIGS. 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 diaphragm 24, a sealing substrate 25, a flow path forming substrate 26, and a wiring substrate 4.

[0021] As shown in FIG. 2, the nozzle substrate 21 is a plate-like member that is long in the Y-axis direction and extends substantially parallel to the XY plane. Here, "substantially parallel" is a concept that includes not only the case of being completely parallel but also the case where it can be regarded as parallel considering errors. In the present embodiment, "substantially parallel" is a concept that includes the case where it can be regarded as parallel considering an error of about 10%. The nozzle substrate 21 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing techniques such as etching, but known materials and manufacturing methods may be arbitrarily adopted for the manufacture of the nozzle substrate 21.

[0022] A plurality of nozzles N are formed on the nozzle substrate 21. Here, the nozzle N is a through hole provided in the nozzle substrate 21. In the present 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 are referred to as a nozzle row Ln1, and the plurality of nozzles N2 extending in the Y-axis direction are referred to as a nozzle row Ln2. Further, hereinafter, the nozzle row Ln1 and the nozzle row Ln2 may be collectively referred to as a nozzle row Ln.

[0023] As shown in FIGS. 2 and 3, a communication plate 22 is provided at a position in the Z2 direction as viewed from the nozzle substrate 21. The communication plate 22 is a plate-like member that is long in the Y-axis direction and extends substantially parallel to the XY plane. The communication plate 22 is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology, but known materials and manufacturing methods may be arbitrarily adopted for the manufacture of the communication plate 22.

[0024] An ink flow path is formed in the communication plate 22. Specifically, in the communication plate 22, one supply flow path BA1 provided to extend in the Y-axis direction (the Y-axis direction is the longitudinal direction) and one supply flow path BA2 provided to extend in the Y-axis direction at a position in the X2 direction as viewed from the supply flow path BA1 are formed. Further, in the communication plate 22, a plurality of connection flow paths BK1, a plurality of connection flow paths BK2, a plurality of communication flow paths BR1, and a plurality of communication flow paths BR2 are formed.

[0025] Among these, the connection channel BK1 communicates with the supply channel BA1 and is provided so as to extend in the Z-axis direction (the Z-axis direction is the longitudinal direction) at a position in the X2 direction when viewed from the supply channel BA1. The communication channel BR1 is provided so as to extend in the Z-axis direction at a position in the X2 direction when viewed from the connection channel BK1. The communication channel BR1 communicates with the nozzle N1 corresponding to the communication channel BR1. The connection channel BK2 communicates with the supply channel BA2 and is provided so as to extend in the Z-axis direction at a position in the X1 direction when viewed from the supply channel BA2. The communication channel BR2 is provided so as to extend in the Z-axis direction at a position in the X1 direction when viewed from the connection channel BK2 and at a position in the X2 direction when viewed from the communication channel BR1. The communication channel BR2 communicates with the nozzle N2 corresponding to the communication channel BR2. Incidentally, hereinafter, the supply channel BA1 and the supply channel BA2 may be collectively referred to as the supply channel BA. Also, hereinafter, the connection channel BK1 and the connection channel BK2 may be collectively referred to as the connection channel BK. Further, hereinafter, the communication channel BR1 and the communication channel BR2 may be collectively referred to as the communication channel BR.

[0026] As shown in FIGS. 2 and 3, a pressure chamber substrate 23 is provided at a position in the Z2 direction when 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 substantially parallel to the XY plane. The pressure chamber substrate 23 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology, but known materials and manufacturing methods may be arbitrarily adopted for the manufacture of the pressure chamber substrate 23.

[0027] An ink flow path is formed in the pressure chamber substrate 23. Specifically, 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 are formed in the pressure chamber substrate 23. Among these, when viewed in the Z-axis direction, the pressure chamber CV1 connects the end portion in the X2 direction of the connection flow path BK1 and the end portion in the X1 direction of the communication flow path BR1, and is provided so as to extend in the X-axis direction (the X-axis direction is the longitudinal direction). The pressure chamber CV2 connects the end portion in the X1 direction of the connection flow path BK2 and the end portion in the X2 direction of the communication flow path BR2, and is provided so as to extend in the X-axis direction when viewed in the Z-axis direction. Hereinafter, the pressure chamber CV1 and the pressure chamber CV2 may be collectively referred to as the pressure chamber CV. Also, the Y-axis direction, which is the arrangement direction of the pressure chambers CV, is an example of the "first direction".

[0028] As shown in FIGS. 2 and 3, a diaphragm 24 is provided at a position in the Z2 direction when viewed from the pressure chamber substrate 23. The diaphragm 24 is a plate-like member that is long in the Y-axis direction and extends substantially parallel to the XY plane, and is a member that can vibrate elastically. In the present embodiment, of the two surfaces of the diaphragm 24 having the Z-axis direction as the normal direction, the surface in the Z2 direction is formed of a non-conductive member. For example, the diaphragm 24 may have an elastic film made of silicon oxide and an insulator film made of zirconium oxide provided at a position in the Z2 direction when viewed from the elastic film.

[0029] As shown in FIGS. 2 and 3, at positions in the Z2 direction as viewed from the diaphragm 24, 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. Hereinafter, the piezoelectric element PZ1 and the piezoelectric element PZ2 may be collectively referred to as the piezoelectric element PZ. The piezoelectric element PZ includes a piezoelectric body Qm, individual electrodes Qc provided individually for a plurality of pressure chambers CV, and a common electrode Qb provided in common for a plurality of pressure chambers CV. Note that the piezoelectric body Qm, the individual electrodes Qc, and the common electrode Qb will be described later with reference to FIGS. 4 and 5. The piezoelectric element PZ is a passive element that deforms in response to a potential change in 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 deformed in response to a potential change in the drive signal Com. The diaphragm 24 vibrates in conjunction with the deformation of the piezoelectric element PZ. When the diaphragm 24 vibrates, the pressure in the pressure chamber CV fluctuates. Then, due to the fluctuation of the pressure in the pressure chamber CV, the ink filled inside the pressure chamber CV is ejected from the nozzle N via the communication flow path BR.

[0030] As shown in FIGS. 2 and 3, at a position in the Z2 direction as viewed from the pressure chamber substrate 23, a sealing substrate 25 for protecting a plurality of piezoelectric elements PZ1 and a plurality of piezoelectric elements PZ2 is provided. The sealing substrate 25 is a plate-like member that is long in the Y-axis direction and extends substantially parallel to the XY plane. The sealing substrate 25 is manufactured, for example, by processing a single-crystalline silicon substrate using semiconductor manufacturing technology, but known materials and manufacturing methods may be arbitrarily adopted for the manufacture of the sealing substrate 25.

[0031] Of the two surfaces of the sealing substrate 25 with the Z-axis direction as the normal direction, a recess for covering a plurality of piezoelectric elements PZ1 and a recess for covering a plurality of piezoelectric elements PZ2 are provided on the surface in the Z1 direction. Hereinafter, the sealing space formed between the diaphragm 24 and the sealing substrate 25 that covers the plurality of piezoelectric elements PZ1 is referred to as the sealing space SP1, and the sealing space formed between the diaphragm 24 and the sealing substrate 25 that covers the plurality of piezoelectric elements PZ2 is referred to as the sealing space SP2. Further, hereinafter, the sealing space SP1 and the sealing space SP2 may be collectively referred to as the sealing space SP. The sealing space SP is a space for sealing the piezoelectric element PZ to prevent the piezoelectric element PZ from deteriorating due to the influence of moisture or the like. Further, hereinafter, when the sealing substrate 25 is viewed in plan in the Z1 direction, the portion that becomes the side wall of the sealing space SP1 is referred to as the side wall WL1, and the portion that becomes the side wall of the sealing space SP2 is referred to as the side wall WL2. Further, hereinafter, the side wall WL1 and the side wall WL2 may be collectively referred to as the side wall WL. Note that the side wall WL is an example of a "wall portion".

[0032] A through hole 250 is provided in the sealing substrate 25. The through hole 250 is a hole that is located between the sealing space SP1 and the sealing space SP2 when the sealing substrate 25 is viewed in the Z1 direction and penetrates from the surface of the sealing substrate 25 in the Z1 direction to the surface of the sealing substrate 25 in the Z2 direction. A wiring substrate 4 is inserted into the through hole 250.

[0033] As shown in FIGS. 2 and 3, a flow path forming substrate 26 is provided at a position in the Z2 direction when viewed from the communication plate 22. The flow path forming substrate 26 is a plate-like member that is long 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 known materials and manufacturing methods may be arbitrarily adopted for the manufacture of the flow path forming substrate 26.

[0034] An ink flow path is formed in the flow path forming substrate 26. Specifically, one supply flow path BB1 and one supply flow path BB2 are formed in the flow path forming substrate 26. Among these, the supply flow path BB1 communicates with the supply flow path BA1 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction when viewed from the supply flow path BA1. The supply flow path BB2 communicates with the supply flow path BA2 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction when viewed from the supply flow path BA2 and at a position in the X2 direction when viewed from the supply flow path BB1. Hereinafter, the supply flow path BB1 and the supply flow path BB2 may be collectively referred to as the supply flow path BB.

[0035] 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. Then, ink is supplied from the liquid container 93 to the supply flow path BB1 through the inlet HL1. The ink supplied from the liquid container 93 to the supply flow path BB1 through the inlet HL1 flows into the supply flow path BA1. A part of the ink flowing into the supply flow path BA1 is filled into the pressure chamber CV1 via the connection flow path BK1. When the piezoelectric element PZ1 is driven by the drive signal Com, a part of the ink filled in the pressure chamber CV1 is discharged from the nozzle N1 via the communication flow path BR1. Also, ink is supplied from the liquid container 93 to the supply flow path BB2 through the inlet HL2. The ink supplied from the liquid container 93 to the supply flow path BB2 through the inlet HL2 flows into the supply flow path BA2. A part of the ink flowing into the supply flow path BA2 is filled into the pressure chamber CV2 via the connection flow path BK2. When the piezoelectric element PZ2 is driven by the drive signal Com, a part of the ink filled in the pressure chamber CV2 is discharged from the nozzle N2 via the communication flow path BR2.

[0036] The flow path forming substrate 26 is provided with a through hole 260. The through hole 260 is located between the supply flow path BB1 and the supply flow path BB2 when the flow path forming substrate 26 is viewed in the Z1 direction, 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.

[0037] As shown in FIGS. 2 and 3, a wiring board 4 is mounted on the surface of the diaphragm 24 in the Z2 direction. The wiring board 4 is a component for electrically connecting the liquid ejection head 1 to the control device 7. As the wiring board 4, for example, a flexible wiring board such as an FPC or an FFC is preferably employed. 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 to supply a drive signal Com to the piezoelectric element PZ under the control of a control signal SI.

[0038] As shown in FIG. 3, the wiring board 4 has an L-shaped cross section bent by a bending line BL in the XZ plane. The wiring board 4 includes a first board portion LS extending in the Z2 direction from the bending line BL in the YZ plane, and a second board portion SS extending in the X1 direction from the bending line BL in the XY plane. The wiring board 4 also includes a first surface FC1 composed of the surface of the first board portion LS in the X2 direction and the surface of the second board portion SS in the Z1 direction, and a second surface FC2 composed of the surface of the first board portion LS in the X1 direction and the surface of the second board portion SS in the Z2 direction. The second surface FC2 is the back surface of the first surface FC1.

[0039] As shown in FIGS. 2 and 3, a compliance sheet CS1 is provided at a position in the Z1 direction as viewed from the communication board 22 so as to block the supply flow path BA1 and the connection flow path BK1, and a compliance sheet CS2 is provided so as to block the supply flow path BA2 and the connection flow path BK2. Hereinafter, the compliance sheet CS1 and the compliance sheet CS2 may be collectively referred to as the compliance sheet CS. The compliance sheet CS is a plate-like member that is long in the Y-axis direction and extends substantially parallel to the XY plane. The compliance sheet CS is formed of an elastic material and absorbs pressure fluctuations of the ink in the supply flow path BA and the connection flow path BK.

[0040] 1-3: Structure of Electrodes FIG. 4 is a plan view of the liquid ejection head 1 when viewed in a plan view in the Z1 direction. Hereinafter, with reference to FIG. 4, the structures of the individual electrode Qc and the common electrode Qb in the liquid ejection head 1 according to the first embodiment will be described.

[0041] The common electrode Qb includes a first common electrode Qb1, a second common electrode Qb2, a first connection electrode Qj1, a second connection electrode Qj2, and a plurality of third connection electrodes Qj3. The individual electrode Qc includes a plurality of first individual electrodes Qc1 and a plurality of second individual electrodes Qc2.

[0042] As shown in FIG. 4, when the liquid ejection head 1 is viewed in a plan view in the Z1 direction, at a position overlapping with a sealing space SP1 which is a space located inside the side wall WL1 of the sealing substrate 25, a plurality of pressure chambers CV1, a plurality of piezoelectric bodies Qm1, a plurality of first individual electrodes Qc1, and a first common electrode Qb1 are provided. The plurality of pressure chambers CV1 are provided so as to correspond one-to-one with the plurality of nozzles N1. However, one nozzle N1 may be shared by the plurality of pressure chambers CV1, or a plurality of nozzles N1 may be provided in one pressure chamber CV1. Also, the plurality of piezoelectric bodies Qm1 are provided so as to correspond one-to-one with the plurality of pressure chambers CV1. Also, the plurality of first individual electrodes Qc1 are provided so as to correspond one-to-one with the plurality of pressure chambers CV1. The first common electrode Qb1 is provided in common for the plurality of pressure chambers CV1. More specifically, the first common electrode Qb1 is provided so as to overlap the plurality of pressure chambers CV1 when the liquid ejection head 1 is viewed in a plan view in the Z1 direction. However, the first common electrode Qb1 may be provided such that each of the plurality of pressure chambers CV1 has a portion that does not overlap the first common electrode Qb1 when the liquid ejection head 1 is viewed in a plan view in the Z1 direction. The sealing substrate 25 is provided so as to overlap the plurality of pressure chambers CV1 when viewed in the Z-axis direction.

[0043] Similarly, when the liquid ejection head 1 is viewed in a plan view in the Z1 direction, a plurality of pressure chambers CV2, a plurality of piezoelectric bodies Qm2, a plurality of second individual electrodes Qc2, and a second common electrode Qb2 are provided at positions overlapping with a sealing space SP2 which is a space located inside a side wall WL2 of the sealing substrate 25. The plurality of pressure chambers CV2 are provided so as to correspond one-to-one with the plurality of nozzles N2. However, one nozzle N2 may be shared by the plurality of pressure chambers CV2, or a plurality of nozzles N2 may be provided in one pressure chamber CV2. Also, the plurality of piezoelectric bodies Qm2 are provided so as to correspond one-to-one with the plurality of pressure chambers CV2. Also, the plurality of second individual electrodes Qc2 are provided so as to correspond one-to-one with the plurality of pressure chambers CV2. The second common electrode Qb2 is provided in common for the plurality of pressure chambers CV2. More specifically, the second common electrode Qb2 is provided so as to overlap the plurality of pressure chambers CV2 when the liquid ejection head 1 is viewed in a plan view in the Z1 direction. However, the second common electrode Qb2 may be provided so that each of the plurality of pressure chambers CV2 has a portion that does not overlap the second common electrode Qb2 when the liquid ejection head 1 is viewed in a plan view in the Z1 direction. The sealing substrate 25 is provided so as to overlap the plurality of pressure chambers CV2 when viewed in the Z-axis direction.

[0044] The first connection electrode Qj1 electrically connects a first common wiring Wb1, which will be described later, provided on the wiring substrate 4, and the first common electrode Qb1. Also, the first connection electrode Qj1 electrically connects the first common wiring Wb1 and the second common electrode Qb2. The first common wiring Wb1 is set to a reference potential VBS. As a result, the first common electrode Qb1 and the second common electrode Qb2 are also set to the reference potential VBS. Also, the first connection electrode Qj1 electrically connects the first common electrode Qb1 and the second common electrode Qb2 at end portions in the Y2 direction in the Y-axis direction of each of the first common electrode Qb1 and the second common electrode Qb2. The second connection electrode Qj2 electrically connects the second common wiring Wb2 (to be described later) provided on the wiring substrate 4 and the first common electrode Qb1. Further, the second connection electrode Qj2 electrically connects the second common wiring Wb2 and the second common electrode Qb2. The second common wiring Wb2 is set to the reference potential VBS. As a result, the first common electrode Qb1 and the second common electrode Qb2 are also set to the reference potential VBS. Also, the second connection electrode Qj2 electrically connects the first common electrode Qb1 and the second common electrode Qb2 at the end portions in the Y1 direction in the Y-axis direction of each of the first common electrode Qb1 and the second common electrode Qb2. As described above, since the common electrode Qb includes the first common electrode Qb1, the second common electrode Qb2, the first connection electrode Qj1, and the second connection electrode Qj2, the entire common electrode Qb is set to the reference potential VBS. In the above embodiment, the common electrode Qb includes one first connection electrode Qj1, and the one first connection electrode Qj1 electrically connects the first common electrode Qb1 and the second common electrode Qb2. However, as another aspect, the common electrode Qb may include two first connection electrodes Qj1, one for electrically connecting the first common electrode Qb1 and the first common wiring Wb1, and the other for electrically connecting the second common electrode Qb2 and the first common wiring Wb1. In this case, the first common wiring Wb1 is electrically connected to each of the two first connection electrodes Qj1 individually. Similarly, in the above embodiment, the common electrode Qb includes one second connection electrode Qj2, and the one second connection electrode Qj2 electrically connects the first common electrode Qb1 and the second common electrode Qb2. However, as another aspect, the common electrode Qb may include two second connection electrodes Qj2, one for electrically connecting the first common electrode Qb1 and the second common wiring Wb2, and the other for electrically connecting the second common electrode Qb2 and the second common wiring Wb2. In this case, the second common wiring Wb2 is electrically connected to each of the two second connection electrodes Qj2 individually. Note that the first common wiring Wb1 and the second common wiring Wb2 will be described later with reference to FIG. 7.

[0045] Further, the third connection electrode Qj3 electrically connects the third common wiring Wb3 (to be described later) provided on the wiring substrate 4 and the first common electrode Qb1. Also, the third connection electrode Qj3 electrically connects the third common wiring Wb3 and the second common electrode Qb2. The third connection electrode Qj3 electrically connects the first common electrode Qb1 and the second common electrode Qb2 between the first connection electrode Qj1 and the second connection electrode Qj2 in the Y-axis direction. The third common wiring Wb3 will be described later with reference to FIG. 7. In this embodiment, it is assumed that a plurality of third connection electrodes Qj3 are provided between the first connection electrode Qj1 and the second connection electrode Qj2. However, the present invention is not limited to such an aspect. One third connection electrode Qj3 may be provided between the first connection electrode Qj1 and the second connection electrode Qj2.

[0046] The common electrode Qb is formed of a conductive material. Specifically, as the material of the common electrode Qb, for example, a metal such as platinum, iridium, gold, or titanium, or a conductive material such as indium tin oxide abbreviated as ITO can be adopted.

[0047] The piezoelectric body Qm1 is provided so as to overlap the pressure chamber CV1 when the liquid ejection head 1 is viewed in plan in the Z1 direction. However, when the liquid ejection head 1 is viewed in plan in the Z1 direction, a part of the pressure chamber CV1 may be provided so as not to overlap the piezoelectric body Qm1. In the example shown in FIG. 4, the piezoelectric body Qm1 is provided so that when the liquid ejection head 1 is viewed in plan in the Z1 direction, the entire piezoelectric body Qm1 is included in the pressure chamber CV1 corresponding to the piezoelectric body Qm1. The relationship between the piezoelectric body Qm2 and the pressure chamber CV2 is the same as the relationship between the piezoelectric body Qm1 and the pressure chamber CV1.

[0048] Note that the piezoelectric bodies Qm1 and Qm2 are formed of, for example, a perovskite-structured crystal film made of a ferroelectric ceramic material exhibiting an electromechanical conversion effect, i.e., a so-called perovskite-type crystal. Specifically, as the materials of the piezoelectric bodies Qm1 and Qm2, for example, ferroelectric piezoelectric materials such as lead zirconate titanate, or those obtained by adding metal oxides such as niobium oxide, nickel oxide, or magnesium oxide to ferroelectric piezoelectric materials such as lead zirconate titanate can be adopted. More specifically, as the materials of the piezoelectric bodies Qm1 and Qm2, for example, lead titanate, lead zirconate titanate, lead zirconate, lanthanum lead titanate, lanthanum lead zirconate titanate, or lead zirconate titanate magnesium niobate can be adopted.

[0049] As described above, a plurality of first individual electrodes Qc1 are provided in the liquid ejection head 1 so as to correspond one-to-one to the plurality of pressure chambers CV1. Each first individual electrode Qc1 is connected to an individual wiring Wc provided on the wiring substrate 4. A drive signal Com is supplied from the control device 7 to the individual wiring Wc. As a result, the drive signal Com is supplied to each first individual electrode Qc1. Note that the individual wiring Wc will be described later with reference to FIG. 7.

[0050] Similarly, a plurality of second individual electrodes Qc2 are provided in the liquid ejection head 1 so as to correspond one-to-one to the plurality of pressure chambers CV2. Each second individual electrode Qc2 is connected to the individual wiring Wc provided on the wiring substrate 4. As described above, the drive signal Com is supplied from the control device 7 to the individual wiring Wc. As a result, the drive signal Com is supplied to each second individual electrode Qc2.

[0051] Further, the individual electrode Qc is formed of a conductive material. Specifically, as the material of the individual electrode Qc, for example, metals such as platinum, iridium, gold, or titanium, or conductive materials such as conductive metal oxides such as indium tin oxide abbreviated as ITO can be adopted.

[0052] In FIG. 4, for the sake of convenience of explanation, in the Y-axis direction, the end portion of the wiring board 4 on the Y2 side is located in the Y2 direction with respect to the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y2 side. However, in the Y-axis direction, the end portion of the wiring board 4 on the Y2 side may be located at the same position as the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y2 side, or may be located in the Y1 direction with respect to the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y2 side. Similarly, in FIG. 4, in the Y-axis direction, the end portion of the wiring board 4 on the Y1 side is located in the Y1 direction with respect to the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y1 side. However, the end portion of the wiring board 4 on the Y1 side may be located at the same position as the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y1 side, or may be located in the Y2 direction with respect to the end portions of the first common electrode Qb1 and the second common electrode Qb2 on the Y1 side. In FIG. 4, the first connection electrode Qj1, the second connection electrode Qj2, and the third connection electrode Qj3 are linear and extend in the X-axis direction. However, in the above case, at least one of these electrodes may be arranged obliquely with respect to the X-axis direction, or may have a bent shape in the XY plane.

[0053] 1-4: Configuration near the first individual electrode Qc1 FIG. 5 is a cross-sectional view taken along the line e-E in FIG. 4.

[0054] As shown in FIG. 5, on the surface of the diaphragm 24 in the Z2 direction among the two surfaces having the Z-axis direction as the normal direction, the first common electrode Qb1, the first individual electrode Qc1, the piezoelectric body Qm1, and the sealing substrate 25 are formed.

[0055] Hereinafter, among the two surfaces of the piezoelectric body Qm1 having the Z-axis direction as the normal direction, the surface in the Z2 direction is referred to as surface PL1. Among the two surfaces of the piezoelectric body Qm1 having the Z-axis direction as the normal direction, the surface in the Z1 direction is referred to as surface PL2. Among the inclined surfaces of the piezoelectric body Qm1, the surface in the X1 direction is referred to as surface PL3, and the surface in the X2 direction is referred to as surface PL4. Among the two surfaces of the diaphragm 24 having the Z-axis direction as the normal direction, the surface in the Z2 direction is referred to as surface QL1.

[0056] On the surfaces PL1 and PL3 of the piezoelectric body Qm1 and the surface QL1 of the diaphragm 24, a first common electrode Qb1 is formed. In other words, the first common electrode Qb1 is installed on the surface PL1 of the piezoelectric body Qm1, which is on the side opposite to the pressure chamber CV1, among the surfaces the piezoelectric body Qm1 has. The end portion of the first common electrode Qb1 in the X2 direction is on the surface PL1 and is located in the X1 direction relative to the surface PL4. Also, the end portion of the first common electrode Qb1 in the X1 direction is on the surface QL1 and is located inside the sealing substrate 25.

[0057] On the surface PL2 of the piezoelectric body Qm1, a first individual electrode Qc1 is formed. In other words, the first individual electrode Qc1 is installed on the surface PL2 of the piezoelectric body Qm1, which is on the side of the pressure chamber CV1, among the surfaces the piezoelectric body Qm1 has. The end portion of the first individual electrode Qc1 in the X1 direction is located in the X2 direction relative to the surface PL3. Also, the first individual electrode Qc1 extends in the X2 direction to the outside of the sealing substrate 25. The first individual electrode Qc1 is connected to an individual wiring Wc provided on the first surface FC1 of the wiring substrate 4 outside the sealing substrate 25.

[0058] 1-5: Configuration near the first connection electrode Qj1 FIG. 6 is a cross-sectional view of the f-F line in FIG. 4.

[0059] As shown in FIG. 6, on the surface QL1 of the diaphragm 24, a first connection electrode Qj1 and a common electrode Qb are formed. The first connection electrode Qj1 and the common electrode Qb are connected to each other at the connection line CL shown in FIG. 6. The end portion of the common electrode Qb in the X1 direction is on the surface QL1 and is located inside the sealing substrate 25. The first connection electrode Qj1 extends in the X2 direction to the outside of the sealing substrate 25. The first connection electrode Qj1 is connected to a first common wiring Wb1 provided on the first surface FC1 of the wiring substrate 4 outside the sealing substrate 25.

[0060] In addition, in the cross-section of the g-G line in FIG. 4, the second connection electrode Qj2 is electrically connected to the second common wiring Wb2 provided on the first surface FC1 within the second substrate portion SS. This configuration is the same as the cross-section of the f-F line shown in FIG. 6, except that the first connection electrode Qj1 is replaced with the second connection electrode Qj2 and the first common wiring Wb1 is replaced with the second common wiring Wb2, so the illustration thereof is omitted. Also, in the cross-section of the h-H line in FIG. 4, the third connection electrode Qj3 is electrically connected to the third common wiring Wb3 provided on the first surface FC1 within the second substrate portion SS. This configuration is the same as the cross-section of the f-F line shown in FIG. 6, except that the first connection electrode Qj1 is replaced with the third connection electrode Qj3 and the first common wiring Wb1 is replaced with the third common wiring Wb3, so the illustration thereof is omitted.

[0061] 1-6: Configuration of Wiring Substrate 4 FIGS. 7 and 8 are explanatory diagrams for explaining various wirings provided on the wiring substrate 4. Hereinafter, among the extending directions of the various wirings in the wiring substrate 4, the direction from the piezoelectric element PZ toward the control device 7 is referred to as the FX1 direction, and the direction opposite to the FX1 direction is referred to as the FX2 direction. The FX1 direction and the FX2 direction are collectively referred to as the FX direction. In the first substrate portion LS portion on the FX1 side of the bending line BL, the FX1 direction coincides with the Z2 direction. On the other hand, in the second substrate portion SS on the FX2 side of the bending line BL, the FX2 direction coincides with the X1 direction. Also, hereinafter, in the wiring substrate 4, the direction from the first surface FC1 toward the second surface FC2 is referred to as the FZ1 direction, and the direction opposite to the FZ1 direction is referred to as the FZ2 direction. The FZ1 direction and the FZ2 direction are collectively referred to as the FZ direction. In the first substrate portion LS on the FX1 side of the bending line BL, the FZ1 direction coincides with the X1 direction, and the FZ2 direction coincides with the X2 direction. In the second substrate portion SS on the FX2 side of the bending line BL, the FZ1 direction coincides with the Z2 direction, and the FZ2 direction coincides with the Z1 direction. Also, hereinafter, in the wiring board 4, a direction orthogonal to both the FX direction and the FZ direction is referred to as the FY direction. Among the FY directions, a direction that coincides with the Y1 direction is referred to as the FY1 direction, and a direction that is opposite to the FY1 direction and coincides with the Y2 direction is referred to as the FY2 direction.

[0062] FIG. 7 is a configuration diagram of the wiring board 4 for explaining the arrangement of wirings and electronic components provided on the first surface FC1 when the first surface FC1 of the wiring board 4 is viewed from the FZ2 side toward the FZ1 side. FIG. 8 is a configuration diagram of the wiring board 4 for explaining the arrangement of wirings provided on the second surface FC2 when the second surface FC2 of the wiring board 4 is viewed from the FZ1 side toward the FZ2 side. In FIG. 8, for convenience of explanation, a part of the wirings and electronic components provided on the first surface FC1 is indicated by broken lines.

[0063] As shown in FIG. 7, on the first surface FC1 of the wiring board 4, a first common wiring Wb1, a second common wiring Wb2, and a plurality of third common wirings Wb3 are provided. In the Y-axis direction, a plurality of third common wirings Wb3 are provided between the first common wiring Wb1 and the second common wiring Wb2. As will be described later, the first common wiring Wb1 is electrically connected to the first connection electrode Qj1. The second common wiring Wb2 is electrically connected to the second connection electrode Qj2. The plurality of third common wirings Wb3 are provided in one-to-one correspondence with the plurality of third connection electrodes Qj3. Each third common wiring Wb3 is connected to the third connection electrode Qj3 corresponding to the third common wiring Wb3. Also, hereinafter, the wiring including the above-described first common wiring Wb1, second common wiring Wb2, and third common wiring Wb3 may be referred to as the common wiring Wb. Note that in the present embodiment, as described above, it is assumed that a plurality of third common wirings Wb3 are provided between the first common wiring Wb1 and the second common wiring Wb2. However, the present invention is not limited to such a mode. One third common wiring Wb3 may be provided between the first common wiring Wb1 and the second common wiring Wb2.

[0064] The first common wiring Wb1 includes a first common wiring connection portion Kb1 installed on the first surface FC1 in the second substrate portion SS and a first common wiring extension portion Lb1 installed on the first surface FC1 in the first substrate portion LS. The first common wiring extension portion Lb1 is electrically connected to the power supply circuit of the control device 7 (not shown), and the reference potential VBS is supplied from the power supply circuit. Therefore, the first common wiring Wb1 including the first common wiring extension portion Lb1 is set to the reference potential VBS. Further, the first common wiring connection portion Kb1 provided in the first common wiring Wb1 is connected to the first connection electrode Qj1. Therefore, the first common electrode Qb1 is also set to the reference potential VBS.

[0065] The second common wiring Wb2 includes a second common wiring connection portion Kb2 installed on the first surface FC1 in the second substrate portion SS and a second common wiring extension portion Lb2 installed on the first surface FC1 in the first substrate portion LS. The second common wiring extension portion Lb2 is electrically connected to the power supply circuit of the control device 7 (not shown), and the reference potential VBS is supplied from the power supply circuit. Therefore, the second common wiring Wb2 including the second common wiring extension portion Lb2 is set to the reference potential VBS. Further, the second common wiring connection portion Kb2 provided in the second common wiring Wb2 is connected to the second connection electrode Qj2. Therefore, the second common electrode Qb2 is also set to the reference potential VBS.

[0066] The third common wiring Wb3 includes a third common wiring connection portion Kb3 installed on the first surface FC1 in the second substrate portion SS and a third common wiring extension portion Lb3 installed on the first surface FC1 in the first substrate portion LS. The third common wiring connection portion Kb3 provided in the third common wiring Wb3 is connected to the third connection electrode Qj3. Note that the end portion on the FX1 side of the third common wiring extension portion Lb3 is located on the FX2 side of the integrated circuit 40 on the first surface FC1 in the first substrate portion LS.

[0067] Further, on the first surface FC1 of the wiring board 4, a plurality of individual wirings Wc, one or more first supply wirings Wd, and one or more second supply wirings We are further provided. In this embodiment, as an example, a case where two first supply wirings Wd and one second supply wiring We are arranged on the first surface FC1 of the wiring board 4 is assumed.

[0068] The individual wiring Wc includes an individual wiring connection portion Kc installed on the first surface FC1 within the second substrate portion SS and an individual wiring extending portion Lc installed on the first surface FC1 within the first substrate portion LS. The individual wiring extending portion Lc is connected to the integrated circuit 40. The plurality of individual wirings Wc are provided so as to correspond one-to-one with the plurality of individual electrodes Qc. The individual wiring connection portion Kc is connected to the individual electrode Qc provided corresponding to the individual wiring Wc including the individual wiring connection portion Kc among the plurality of individual electrodes Qc.

[0069] One or more first supply wirings Wd are connected to the integrated circuit 40 within the first substrate portion LS. Also, one or more first supply wirings Wd are connected to the control device 7 at the end on the FX1 side. A drive signal Com is supplied from the control device 7 to the integrated circuit 40 via one or more first supply wirings Wd.

[0070] One or more second supply wirings We are connected to the integrated circuit 40 within the first substrate portion LS. Also, one or more second supply wirings We are connected to the control device 7 at the end on the FX1 side. A control signal SI is supplied from the control device 7 to the integrated circuit 40 via one or more second supply wirings We.

[0071] The integrated circuit 40 switches whether to supply the drive signal Com to the individual wiring Wc based on the control signal SI. When the integrated circuit 40 supplies the drive signal Com to the individual wiring Wc, the individual wiring Wc supplies the drive signal Com to the individual electrode Qc. In other words, the individual wiring Wc applies a voltage to the individual electrode Qc.

[0072] On the first surface FC1 of the wiring board 4 shown in FIG. 7, the first common wiring Wb1 is connected to the first connection electrode Qj1 on the FY2 side, which is one side along the FY direction, rather than the connection positions of the plurality of individual electrodes Qc and the plurality of individual wirings Wc. Also, on the first surface FC1, the second common wiring Wb2 is connected to the second connection electrode Qj2 on the FY1 side, which is the other side along the FY direction, rather than the connection positions of the plurality of individual electrodes Qc and the plurality of individual wirings Wc. In FIG. 7, for convenience of explanation, each of the first common wiring Wb1, the second common wiring Wb2, and the plurality of individual wirings Wc is in a straight line extending in the FX direction. However, at least one of these wirings may be arranged obliquely with respect to the FX direction or may have a bent shape within the first surface FC1.

[0073] In FIG. 8, an auxiliary wiring Aw is provided on the second surface FC2 of the wiring board 4. More specifically, the auxiliary wiring Aw is provided on the second surface FC2 within the first substrate portion LS of the wiring board 4. As will be described later, the auxiliary wiring Aw is provided to reduce the resistance of the common electrode Qb.

[0074] When the wiring board 4 is viewed in plan in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 are installed at overlapping positions. Also, in the FZ direction, when the wiring board 4 is viewed in plan, the auxiliary wiring Aw, a part of the first common wiring Wb1, a part of the second common wiring Wb2, and a part of the third common wiring Wb3 are installed at overlapping positions. Also, in the first substrate portion LS, the cross-sectional area of the cross-section of the auxiliary wiring Aw orthogonal to the FX direction is larger than the cross-sectional area of the cross-section of the individual wiring Wc orthogonal to the FX direction. Note that the auxiliary wiring Aw is not electrically connected to the individual wiring Wc.

[0075] The wiring board 4 is provided with a first through hole Jb1, a second through hole Jb2, and a plurality of third through holes Jb3. The plurality of third through holes Jb3 are provided in a one-to-one correspondence with the plurality of third common wirings Wb3. In the following, the first through hole Jb1, the second through hole Jb2, and the third through hole Jb3 may be collectively referred to as the through hole Jb.

[0076] When the wiring board 4 is viewed in plan in the FZ direction, the first through-hole Jb1 is installed at a position overlapping with a first common wiring extending portion Lb1 provided in the first common wiring Wb1. In the FZ direction, the first common wiring Wb1 is electrically connected to the auxiliary wiring Aw through a conductor passing through the first through-hole Jb1 at a first connection point Jt1 that overlaps with the first through-hole Jb1. As described above, the first common wiring Wb1 is connected to the common electrode Qb. Therefore, the first common wiring Wb1 electrically connects the auxiliary wiring Aw and the common electrode Qb.

[0077] When the wiring board 4 is viewed in plan in the FZ direction, the second through-hole Jb2 is installed at a position overlapping with a second common wiring extending portion Lb2 provided in the second common wiring Wb2. In the FZ direction, the second common wiring Wb2 is electrically connected to the auxiliary wiring Aw through a conductor passing through the second through-hole Jb2 at a second connection point Jt2 that overlaps with the second through-hole Jb2. As described above, the second common wiring Wb2 is connected to the common electrode Qb. Therefore, the second common wiring Wb2 electrically connects the auxiliary wiring Aw and the common electrode Qb.

[0078] As a result, the auxiliary wiring Aw electrically connects the first common wiring Wb1 and the second common wiring Wb2.

[0079] When the wiring board 4 is viewed in plan in the FZ direction, the third through-hole Jb3 is installed at a position overlapping with an end portion of the third common wiring Wb3. In the FZ direction, the third common wiring Wb3 is electrically connected to the auxiliary wiring Aw through a conductor passing through the third through-hole Jb3 at a third connection point Jt3 that overlaps with the third through-hole Jb3. As described above, since a third common wiring connection portion Kb3 provided in the third common wiring Wb3 is connected to the third connection electrode Qj3, the third common wiring Wb3 electrically connects the common electrode Qb and the auxiliary wiring Aw.

[0080] In the following, the first connection point Jt1, the second connection point Jt2, and the third connection point Jt3 may be collectively referred to as the connection point Jt.

[0081] The materials of the common wiring Wb, the individual wiring Wc, the first supply wiring Wd, the second supply wiring We, and the auxiliary wiring Aw are appropriately selected from gold, copper, aluminum, etc.

[0082] As described above, according to the conventional technology, since it has a structure in which an auxiliary electrode is laminated on the common electrode Qb provided in the liquid ejection head, there is a problem that the thickness of the liquid ejection head increases as compared with the mode in which the liquid ejection head does not have an auxiliary electrode. On the other hand, according to the liquid ejection head 1 according to the present embodiment, instead of laminating the auxiliary electrode on the common electrode Qb, by providing the auxiliary wiring Aw on the wiring board 4 existing outside the sealing substrate 25, it is not necessary to increase the thickness of the liquid ejection head 1.

[0083] As a further problem, when the common electrode Qb has a high resistance, the occurrence of electromagnetic crosstalk tends to increase as compared with the case of a low resistance. Specifically, when the common electrode Qb has a high resistance, it is more susceptible to the potential fluctuation of the drive signal Com supplied to the individual electrode Qc than in the case of a low resistance. When the potential of the common electrode Qb fluctuates, the voltage applied between the common electrode Qb and the individual electrode Qc constituting the piezoelectric element PZ fluctuates from the desired voltage, which may cause a problem of deterioration in printing quality. In the liquid ejection head 1 according to the present embodiment, by providing the auxiliary wiring Aw on the wiring board 4, the common electrode Qb can be made to have a low resistance without increasing the thickness of the liquid ejection head 1. As a result, the liquid ejection head 1 according to the present embodiment can suppress a decrease in printing quality.

[0084] Also, when wiring such as an auxiliary electrode is provided in the vicinity of the piezoelectric element PZ, the reliability and characteristics of the piezoelectric element PZ may be adversely affected by the plating used for the wiring. In the liquid ejection head 1 according to the present embodiment, since wiring such as an auxiliary electrode is not provided in the vicinity of the piezoelectric element PZ, such an adverse effect can be suppressed.

[0085] 1-7: Effects achieved by the first embodiment The liquid ejection head 1 according to this embodiment includes a nozzle substrate 21, a pressure chamber substrate 23, a piezoelectric element PZ, and a wiring substrate 4. The nozzle substrate 21 is provided with nozzles N for ejecting ink. The pressure chamber substrate 23 is provided with a plurality of pressure chambers CV for applying pressure to the ink. The piezoelectric element PZ includes a piezoelectric body Qm, individual electrodes Qc provided individually for the plurality of pressure chambers CV, and a common electrode Qb provided in common for the plurality of pressure chambers CV. The wiring substrate 4 is provided with an individual wiring Wc for applying a voltage to the individual electrode Qc, a common wiring Wb for applying a voltage to the common electrode Qb, and an auxiliary wiring Aw that is electrically connected to the common wiring Wb and reduces the resistance of the common electrode Qb.

[0086] Since the liquid ejection head 1 has the above configuration, instead of laminating an auxiliary electrode on the common electrode Qb, by providing the auxiliary wiring Aw on the wiring substrate 4, the resistance of the common electrode Qb can be reduced without increasing the thickness of the liquid ejection head 1.

[0087] Also, in the liquid ejection head 1 according to this embodiment, the individual wiring Wc and the common wiring Wb are provided on the first surface FC1 of the wiring substrate 4. The auxiliary wiring Aw is provided on the second surface FC2 on the back of the first surface FC1 of the wiring substrate 4.

[0088] Since the liquid ejection head 1 has the above configuration, the size of the wiring substrate 4 can be reduced as compared with a structure in which the individual wiring Wc, the common wiring Wb, and the auxiliary wiring Aw are provided on the same surface of the wiring substrate 4.

[0089] Also, in the liquid ejection head 1 according to this embodiment, the common wiring Wb and the auxiliary wiring Aw are electrically connected via a through hole Jb provided in the wiring substrate 4.

[0090] Since the liquid ejection head 1 has the above configuration, the common wiring Wb and the auxiliary wiring Aw can be provided on different surfaces of the wiring substrate 4, so that the size of the wiring substrate 4 can be reduced.

[0091] In addition, in the liquid ejection head 1 according to the present embodiment, the wiring board 4 is further provided with an integrated circuit 40 to which individual wirings Wc are connected. When the wiring board 4 is viewed in plan, the auxiliary wiring Aw and the integrated circuit 40 are installed at positions overlapping each other.

[0092] Since the liquid ejection head 1 has the above configuration, a shielding effect is brought about by installing the auxiliary wiring Aw and the integrated circuit 40 at positions overlapping each other.

[0093] In addition, in the liquid ejection head 1 according to the present embodiment, the common wiring Wb includes a first common wiring Wb1 and a second common wiring Wb2. The auxiliary wiring Aw electrically connects the first common wiring Wb1 and the second common wiring Wb2.

[0094] Since the liquid ejection head 1 has the above configuration, noise generated in the integrated circuit 40 is suppressed.

[0095] In addition, in the liquid ejection head 1 according to the present embodiment, when the arrangement direction of the plurality of pressure chambers CV is the first direction, the first common wiring Wb1 is connected to the common electrode Qb on one side along the first direction from the connection position between the individual electrode Qc and the individual wiring Wc. The second common wiring Wb2 is connected to the common electrode Qb on the other side along the first direction from the connection position between the individual electrode Qc and the individual wiring Wc.

[0096] Since the liquid ejection head 1 has the above configuration, noise generated in the integrated circuit 40 is suppressed.

[0097] In addition, when the arrangement direction of the plurality of pressure chambers CV of the liquid ejection head 1 according to the present embodiment is the first direction, in the first direction, a third common wiring Wb3 is further provided between the first common wiring Wb1 and the second common wiring Wb2 and electrically connects the common electrode Qb and the auxiliary wiring Aw.

[0098] Since the liquid ejection head 1 has the above configuration, a voltage drop generated near the center in the arrangement direction of the plurality of pressure chambers CV is suppressed in the common electrode Qb.

[0099] Further, in the liquid ejection head 1 according to the present embodiment, the first common wiring Wb1 is electrically connected to the auxiliary wiring Aw at a first connection point Jt1 located in the middle of the first common wiring Wb1. The third common wiring Wb3 is electrically connected to the auxiliary wiring Aw at one end of the third common wiring Wb3.

[0100] Since the liquid ejection head 1 has the above configuration, a voltage drop generated near the center in the arrangement direction of the plurality of pressure chambers CV is suppressed in the common electrode Qb.

[0101] Further, in the liquid ejection head 1 according to the present embodiment, the cross-sectional area of the auxiliary wiring Aw is larger than the cross-sectional area of the individual wiring Wc.

[0102] By making the cross-sectional area of the auxiliary wiring Aw larger, the common electrode Qb can be made to have a lower resistance.

[0103] Further, in the liquid ejection head 1 according to the present embodiment, the common electrode Qb is provided on the surface of the piezoelectric body Qm that is opposite to the surface on the pressure chamber CV side. The individual electrode Qc is provided on the surface of the piezoelectric body Qm that is on the pressure chamber CV side.

[0104] Since the common electrode Qb and the individual electrode Qc are provided on the surfaces of the piezoelectric body Qm opposite to each other, the piezoelectric element PZ can be deformed. Subsequently, due to the deformation of the piezoelectric element PZ, the diaphragm 24 vibrates, causing the pressure in the pressure chamber CV to fluctuate, and the ink filled inside the pressure chamber CV is ejected from the nozzle N.

[0105] Further, the liquid ejection device 100 according to the present embodiment includes the above-described liquid ejection head 1 and a control device 7 that controls the liquid ejection operation from the liquid ejection head 1.

[0106] Since the liquid ejection device 100 has the above configuration, instead of laminating the auxiliary electrode on the common electrode Qb, the auxiliary wiring Aw is provided on the wiring substrate 4, so that the common electrode Qb can be made to have a lower resistance without increasing the thickness of the liquid ejection head 1.

[0107] 2: Second Embodiment Hereinafter, the liquid ejection device 100 according to the second embodiment will be described with reference to FIG. 9. For the sake of simplicity of explanation, hereinafter, mainly, the differences between the liquid ejection device 100 according to the second embodiment and the liquid ejection device 100 according to the first embodiment will be described. In addition, among the components provided in the liquid ejection device 100 according to the second embodiment, for the components identical to those in the liquid ejection device 100 according to the first embodiment, the same reference numerals may be used and the description of their functions may be omitted.

[0108] 2-1: Structure of Electrodes The liquid ejection device 100 according to the second embodiment includes a liquid ejection head 1A instead of the liquid ejection head 1 provided in the liquid ejection device 100 according to the first embodiment. Hereinafter, while referring to FIG. 9, the structures of the individual electrode Qc and the common electrode Qb in the liquid ejection head 1A according to the second embodiment will be described.

[0109] FIG. 9 is a plan view of the liquid ejection head 1A when viewed in a plan view in the Z1 direction.

[0110] Unlike the liquid ejection head 1, the liquid ejection head 1A includes a first individual electrode Qc1a instead of the first individual electrode Qc1 adjacent to the third connection electrode Qj3 in the Y-axis direction. Similarly, unlike the liquid ejection head 1, the liquid ejection head 1A includes a second individual electrode Qc2a instead of the second individual electrode Qc2 adjacent to the third connection electrode Qj3 in the Y-axis direction.

[0111] The first individual electrode Qc1a, unlike the first individual electrode Qc1, has an end on the X2 side located in the Y1 direction rather than the end on the X1 side in the XY plane. As shown in FIG. 9, the first individual electrode Qc1a may have a bent shape in the XY plane or may have a linear shape inclined with respect to the Y axis.

[0112] The second individual electrode Qc2a, unlike the second individual electrode Qc2, has an end on the X1 side located in the Y2 direction rather than the end on the X2 side in the XY plane. As shown in FIG. 9, the second individual electrode Qc2a may have a bent shape in the XY plane or may have a linear shape inclined with respect to the Y axis.

[0113] Hereinafter, the connection point between the first individual electrode Qc1 and the individual wiring Wc is referred to as connection point Jc1. The connection point between the second individual electrode Qc2 and the individual wiring Wc is referred to as connection point Jc2. The connection point between the first individual electrode Qc1a and the individual wiring Wc is referred to as connection point Jc1a. The connection point between the second individual electrode Qc2a and the individual wiring Wc is referred to as connection point Jc2a. Also, hereinafter, the connection points Jc1, Jc2, Jc1a, and Jc2a are collectively referred to as connection points Jcc. Also, hereinafter, the connection point between the third connection electrode Qj3 and the third common wiring Wb3 is referred to as connection point Jj3.

[0114] In the wiring substrate 4 provided in the liquid ejection head 1A, among the plurality of connection points Jcc, a common electrode Qb and an individual electrode Qc are provided so that the connection point Jj3 does not intervene between the adjacent connection points Jc1 and Jc2. Also, in the wiring substrate 4 provided in the liquid ejection head 1A, a common electrode Qb and an individual electrode Qc are provided so that the connection point Jj3 intervenes between the adjacent connection points Jc1a and Jc2a among the plurality of connection points Jcc.

[0115] In the wiring board 4, the connection point Jc1 between the first individual electrode Qc1 and the individual wiring Wc and the connection point Jc2 between the second individual electrode Qc2 and the individual wiring Wc are adjacent to each other in the Y-axis direction without the intervention of the connection point Jj3 between the third connection electrode Qj3 and the third common wiring Wb3. On the other hand, the connection point Jc1a between the first individual electrode Qc1a and the individual wiring Wc and the connection point Jc2a between the second individual electrode Qc2a and the individual wiring Wc are adjacent to each other in the Y-axis direction with the connection point Jj3 between the third connection electrode Qj3 and the third common wiring Wb3 intervening therebetween.

[0116] The end portion of the first individual electrode Qc1 on the X2 side is at the same position as the end portion on the X1 side in the Y-axis direction. On the other hand, as described above, the end portion of the first individual electrode Qc1a on the X2 side is located in the Y1 direction with respect to the end portion on the X1 side in the XY plane. Also, the end portion of the second individual electrode Qc2 on the X1 side is at the same position as the end portion on the X2 side in the Y-axis direction. On the other hand, as described above, the end portion of the second individual electrode Qc2a on the X1 side is located in the Y2 direction with respect to the end portion on the X2 side in the XY plane. Therefore, the distance between the connection point Jc1a and the connection point Jc2a is larger than the distance between the connection point Jc1 and the connection point Jc2. Note that the connection point Jc1a is an example of the "first connection point". The connection point Jc2a is an example of the "second connection point". The connection point Jc1 is an example of the "third connection point". The connection point Jc2 is an example of the "fourth connection point".

[0117] 2-2: Effects of the Second Embodiment In the liquid ejection head 1A according to the present embodiment, among the connection points Jcc between the individual wiring Wc and the individual electrode Qc, the connection point Jj3 between the third common wiring Wb3 and the third connection electrode Qj3 intervenes between the connection point Jc1a and the connection point Jc2a that are adjacent to each other in the Y-axis direction. The connection point Jj3 between the third common wiring Wb3 and the third connection electrode Qj3 does not intervene between the connection point Jc1 and the connection point Jc2 that are adjacent to each other in the Y-axis direction among the connection points Jcc between the individual wiring Wc and the individual electrode Qc. The distance between the connection point Jc1a and the connection point Jc2a in the Y-axis direction is larger than the distance between the connection point Jc1 and the connection point Jc2 in the Y-axis direction.

[0118] The distance between the connection points Jc1a and Jc2a sandwiching the connection point Jj3 is larger than the distance between the connection points Jc1 and Jc2 not sandwiching the connection point Jj3, so that the noise induced in the third connection electrode Qj3 having the connection point Jj3 can be suppressed.

[0119] 3: Third Embodiment Hereinafter, with reference to FIG. 10, the liquid ejection device 100 according to the third embodiment will be described. For the sake of simplicity of explanation, hereinafter, mainly, the differences between the liquid ejection device 100 according to the third embodiment and the liquid ejection device 100 according to the first embodiment will be described. In addition, among the components provided in the liquid ejection device 100 according to the third embodiment, for the components identical to those of the liquid ejection device 100 according to the first embodiment, the same reference numerals may be used and the description of their functions may be omitted.

[0120] 3-1: Structure of Electrodes The liquid ejection device 100 according to the third embodiment includes a liquid ejection head 1B instead of the liquid ejection head 1 provided in the liquid ejection device 100 according to the first embodiment. Hereinafter, while referring to FIG. 10, the structures of the individual electrodes Qc and the common electrode Qb in the liquid ejection head 1B according to the third embodiment will be described.

[0121] FIG. 10 is a plan view of the liquid ejection head 1B when the liquid ejection head 1B is viewed in a plan view in the Z1 direction. For the sake of simplicity of explanation, in FIG. 10, among the components provided in the liquid ejection head 1B, the wiring board 4 and the elements on the X1 side of the wiring board 4 are illustrated.

[0122] In the liquid ejection head 1B, the extending directions of the plurality of pressure chambers CV1 are inclined with respect to the Y-axis direction.

[0123] In FIG. 10, the plurality of pressure chambers CV1 include a pressure chamber CV1(1), a pressure chamber CV1(2), a pressure chamber CV1(3), and a pressure chamber CV1(4). Hereinafter, in the liquid ejection head 1B illustrated in FIG. 10, the pressure chambers CV1(1) to CV1(4) may be collectively referred to as a set of pressure chamber group CV1s. Further, the plurality of first individual electrodes Qc1 include a first individual electrode Qc1(1), a first individual electrode Qc1(2), a first individual electrode Qc1(3), and a first individual electrode Qc1(4). Hereinafter, the first individual electrodes Qc1(1) to Qc1(4) corresponding to a set of pressure chamber group CV1s may be collectively referred to as a set of first individual electrode group Qc1s.

[0124] A piezoelectric body Qm1(1) is provided corresponding to the pressure chamber CV1(1). A piezoelectric body Qm1(2) is provided corresponding to the pressure chamber CV1(2). A piezoelectric body Qm1(3) is provided corresponding to the pressure chamber CV1(3). A piezoelectric body Qm1(4) is provided corresponding to the pressure chamber CV1(4).

[0125] The first individual electrode Qc1(1) is connected to the piezoelectric body Qm1(1). The first individual electrode Qc1(1) has a linear shape in the XY plane. Further, the extending direction of the first individual electrode Qc1(1) is inclined with respect to the Y-axis direction.

[0126] Hereinafter, among the extending directions of the first individual electrode Qc1(1), the direction from the wiring substrate 4 toward the piezoelectric body Qm(1) is referred to as the GX1 direction, and the direction opposite to the GX1 direction is referred to as the GX2 direction. The GX1 direction and the GX2 direction are collectively referred to as the GX direction. Further, hereinafter, among the normal directions of the first individual electrode Qc1(1), the direction coinciding with the Z1 direction is referred to as the GZ1 direction, and the direction coinciding with the Z2 direction is referred to as the GZ2 direction. The GZ1 direction and the GZ2 direction are collectively referred to as the GZ direction. Further, hereinafter, the direction orthogonal to both the GX direction and the GZ direction is referred to as the GY direction. Among the GY directions, the direction toward the X1 direction and the Y1 direction is referred to as the GY1 direction. Among the GY directions, the direction toward the X2 direction and the Y2 direction is referred to as the GY2 direction.

[0127] A first individual electrode Qc1(2) is connected to the piezoelectric body Qm1(2). The first individual electrode Qc1(2) has a bent shape in the XY plane. The first individual electrode Qc1(2) includes a first electrode portion Qc1(2a), a second electrode portion Qc1(2b), and a third electrode portion Qc1(2c). The first electrode portion Qc1(2a) extends in the GX direction. Also, the end portion on the GX2 side of the first electrode portion Qc1(2a) is connected to the individual wiring Wc within the wiring substrate 4. Also, the end portion on the GX1 side of the first electrode portion Qc1(2a) is connected to the second electrode portion Qc1(2b). The second electrode portion Qc1(2b) extends in the GY direction. Also, the end portion on the GY2 side of the second electrode portion Qc1(2b) is connected to the first electrode portion Qc1(2a). Also, the end portion on the GY1 side of the second electrode portion Qc1(2b) is connected to the third electrode portion Qc1(2c). The third electrode portion Qc1(2c) extends in the GX direction. Also, the end portion on the GX2 side of the third electrode portion Qc1(2c) is connected to the second electrode portion Qc1(2b). Also, the end portion on the GX1 side of the third electrode portion Qc1(2c) is connected to the piezoelectric body Qm1(1).

[0128] A first individual electrode Qc1(3) is connected to the piezoelectric body Qm1(3). The first individual electrode Qc1(3) has a bent shape in the XY plane. The first individual electrode Qc1(3) includes a first electrode portion Qc1(3a), a second electrode portion Qc1(3b), a third electrode portion Qc1(3c), a fourth electrode portion Qc1(3d), and a fifth electrode portion Qc1(3e). The first electrode portion Qc1(3a) extends in the GX direction. Also, the end portion on the GX2 side of the first electrode portion Qc1(3a) is connected to the individual wiring Wc within the wiring substrate 4. Also, the end portion on the GX1 side of the first electrode portion Qc1(3a) is connected to the second electrode portion Qc1(3b). The second electrode portion Qc1(3b) extends in the GY direction. Also, the end portion on the GY2 side of the second electrode portion Qc1(3b) is connected to the first electrode portion Qc1(3a). Also, the end portion on the GY1 side of the second electrode portion Qc1(3b) is connected to the third electrode portion Qc1(3c). The third electrode portion Qc1(3c) extends in the GX direction. Also, the end portion of the third electrode portion Qc1(3c) on the GX2 side is connected to the second electrode portion Qc1(3b). Further, the end portion of the third electrode portion Qc1(3c) on the GX1 side is connected to the fourth electrode portion Qc1(3d). The fourth electrode portion Qc1(3d) extends in the GY direction. Also, the end portion of the fourth electrode portion Qc1(3d) on the GY2 side is connected to the third electrode portion Qc1(3c). Further, the end portion of the fourth electrode portion Qc1(3d) on the GY1 side is connected to the fifth electrode portion Qc1(3e). The fifth electrode portion Qc1(3e) extends in the GX direction. Also, the end portion of the fifth electrode portion Qc1(3e) on the GX2 side is connected to the fourth electrode portion Qc1(3d). Further, the end portion of the fifth electrode portion Qc1(3e) on the GX1 side is connected to the piezoelectric body Qm1(3).

[0129] A first individual electrode Qc1(4) is connected to the piezoelectric body Qm1(4). The first individual electrode Qc1(4) has a shape bent in the XY plane. The first individual electrode Qc1(4) includes a first electrode portion Qc1(4a), a second electrode portion Qc1(4b), a third electrode portion Qc1(4c), a fourth electrode portion Qc1(4d), a fifth electrode portion Qc1(4e), a sixth electrode portion Qc1(4f), and a seventh electrode portion Qc1(4g). The first electrode portion Qc1(4a) extends in the GX direction. Also, the end portion of the first electrode portion Qc1(4a) on the GX2 side is connected to an individual wiring Wc within the wiring substrate 4. Further, the end portion of the first electrode portion Qc1(4a) on the GX1 side is connected to the second electrode portion Qc1(4b). The second electrode portion Qc1(4b) extends in the GY direction. Also, the end portion of the second electrode portion Qc1(4b) on the GY2 side is connected to the first electrode portion Qc1(4a). Further, the end portion of the second electrode portion Qc1(4b) on the GY1 side is connected to the third electrode portion Qc1(4c). The third electrode portion Qc1(4c) extends in the GX direction. Also, the end portion of the third electrode portion Qc1(4c) on the GX2 side is connected to the second electrode portion Qc1(4b). Further, the end portion of the third electrode portion Qc1(4c) on the GX1 side is connected to the fourth electrode portion Qc1(4d). The fourth electrode portion Qc1(4d) extends in the GY direction. Also, the end portion on the GY2 side of the fourth electrode portion Qc1(4d) is connected to the third electrode portion Qc1(4c). Also, the end portion on the GY1 side of the fourth electrode portion Qc1(4d) is connected to the fifth electrode portion Qc1(4e). The fifth electrode portion Qc1(4e) extends in the GX direction. Also, the end portion on the GX2 side of the fifth electrode portion Qc1(4e) is connected to the fourth electrode portion Qc1(4d). Also, the end portion on the GX1 side of the fifth electrode portion Qc1(4e) is connected to the sixth electrode portion Qc1(4f). The sixth electrode portion Qc1(4f) extends in the GY direction. Also, the end portion on the GY2 side of the sixth electrode portion Qc1(4f) is connected to the fifth electrode portion Qc1(4e). Also, the end portion on the GY1 side of the sixth electrode portion Qc1(4f) is connected to the seventh electrode portion Qc1(4g). The seventh electrode portion Qc1(4g) extends in the GX direction. Also, the end portion on the GX2 side of the seventh electrode portion Qc1(4g) is connected to the sixth electrode portion Qc1(4f). Also, the end portion on the GX1 side of the seventh electrode portion Qc1(4g) is connected to the piezoelectric body Qm1(4).

[0130] A third connection electrode Qj3 is installed between two of the first individual electrode groups Qc1s. The extending direction of the third connection electrode Qj3 is inclined with respect to the Y-axis direction.

[0131] In the example shown in FIG. 10, the first individual electrodes Qc1(2) to Qc1(4) have a bent shape in the XY plane, but may be linear.

[0132] Also, in FIG. 10, as an example, one set of pressure chamber groups CV1s includes four pressure chambers CV1. However, the number of pressure chambers CV1 included in one set of pressure chamber groups CV1s may be one to three, or may be five or more. Similarly, in FIG. 10, as an example, one set of first individual electrode groups Qc1s includes four first individual electrodes Qc1. However, the number of first individual electrodes Qc1 included in one set of first individual electrode groups Qc1s may be one to three, or may be five or more.

[0133] 4: Modification Example Each of the above forms can be variously modified. Specific modification modes are exemplified below. The modes exemplified below and the modes shown in the above embodiments can be appropriately combined within a range that does not conflict with each other. For elements in the modification examples exemplified below whose actions and functions are equivalent to those in the embodiments, the reference numerals referred to in the above description are reused, and the detailed descriptions of each are appropriately omitted as needed.

[0134] 4-1: Modification Example 1 FIGS. 11 and 12 are explanatory diagrams for explaining various wirings provided on the wiring board 4A according to this modification example. FIG. 11 is a configuration diagram of the wiring board 4A for explaining the arrangement of wirings and electronic components provided on the first surface FC1 when viewing the first surface FC1 of the wiring board 4A from the FZ2 side toward the FZ1 side. FIG. 12 is a configuration diagram of the wiring board 4A for explaining the arrangement of wirings provided on the second surface FC2 when viewing the second surface FC2 of the wiring board 4A from the FZ1 side toward the FZ2 side. In FIG. 12, for convenience of explanation, a part of the wirings and electronic components provided on the first surface FC1 is indicated by a broken line.

[0135] In the first embodiment, when the wiring board 4 is viewed in a plan view in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 were installed at positions overlapping each other. On the other hand, as in this modification example shown in FIGS. 11 and 12, when the wiring board 4A is viewed in a plan view in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 may be installed at non-overlapping positions.

[0136] By not installing the auxiliary wiring Aw at the location corresponding to the integrated circuit 40 within the second surface FC2, the generation of noise in the integrated circuit 40 is suppressed.

Description of Reference Numerals

[0137] 1, 1A, 1B: Liquid ejection head, 4, 4A: Wiring board, 7: Control device, 21: Nozzle board, 22: Communication board, 23: Pressure chamber board, 24: Diaphragm, 25: Sealing board, 26: Flow path forming board, 40: Integrated circuit, 100: Liquid ejection device, 250, 260: Through hole, Aw: Auxiliary wiring, BL: Bend line, CV, CV1, CV2: Pressure chamber, FC1: First surface, FC2: Second surface, Jb: Through hole, Jb1: First through hole, Jb2: Second through hole, Jb3: Third through hole, Jc1, Jc1a, Jc2, Jc2a, Jcc, Jj3, Jt: Connection point, Jt1: First connection point, Jt2: Second connection point, Jt3: Third connection point, Kb1: First common wiring connection part, Kb2: Second common wiring connection part, Kb3: Third common wiring connection part, Kc: Individual wiring connection part, LS: First board part, Lb1: First common wiring extending part, Lb2: Second common wiring extending part, Lb3: Third common wiring extending part, Lc: Individual wiring extending part, N, N1, N2: Nozzle, PL1, PL2, PL3, PL4: Surface, PZ, PZ1, PZ2: Piezoelectric element, QL1: Surface, Qb: Common electrode, Qb1: First common electrode, Qb2: Second common electrode, Qc: Individual electrode, Qc1, Qc1a: First individual electrode, Qc2, Qc2a: Second individual electrode, Qj1: First connection electrode, Qj2: Second connection electrode, Qj3: Third connection electrode, Qm, Qm1, Qm2: Piezoelectric body, Wb: Common wiring, Wb1: First common wiring, Wb2: Second common wiring, Wb3: Third common wiring, Wc: Individual wiring, Wd: First supply wiring, We: Second supply wiring

Claims

1. a nozzle substrate provided with a nozzle for discharging a liquid; a pressure chamber substrate provided with a plurality of pressure chambers for applying pressure to the liquid; a piezoelectric element including a piezoelectric body, individual electrodes provided individually for the plurality of pressure chambers, and a common electrode provided commonly for the plurality of pressure chambers; a wiring substrate provided with an individual wiring for applying a voltage to the individual electrode, a common wiring for applying a voltage to the common electrode, and an auxiliary wiring that is electrically connected to the common wiring and reduces the resistance of the common electrode. A liquid discharge head characterized by comprising:

2. the individual wiring and the common wiring are provided on a first surface of the wiring substrate; the auxiliary wiring is provided on a second surface on the back of the first surface of the wiring substrate; The liquid discharge head according to claim 1, characterized in that:

3. the common wiring and the auxiliary wiring are electrically connected via a through hole provided in the wiring substrate; The liquid discharge head according to claim 1, characterized in that:

4. the wiring substrate is further provided with an integrated circuit to which the individual wiring is connected; when the wiring substrate is viewed in plan, the auxiliary wiring and the integrated circuit are installed at positions overlapping each other; The liquid discharge head according to claim 2, characterized in that:

5. the wiring substrate is further provided with an integrated circuit to which the individual wiring is connected; when the wiring substrate is viewed in plan, the auxiliary wiring and the integrated circuit are installed at non-overlapping positions; The liquid discharge head according to claim 2, characterized in that:

6. the common wiring includes a first common wiring and a second common wiring; the auxiliary wiring electrically connects the first common wiring and the second common wiring; The liquid discharge head according to claim 1, characterized in that:

7. when the arrangement direction of the plurality of pressure chambers is defined as a first direction; the first common wiring is connected to the common electrode on one side along the first direction from the connection position between the individual electrode and the individual wiring; the second common wiring is connected to the common electrode on the other side along the first direction from the connection position between the individual electrode and the individual wiring; The liquid discharge head according to claim 6, characterized in that:

8. when the arrangement direction of the plurality of pressure chambers is defined as a first direction; in the first direction, a third common wiring is further provided between the first common wiring and the second common wiring, and electrically connects the common electrode and the auxiliary wiring. The liquid ejection head according to claim 6, characterized in that...

9. The first common wiring is electrically connected to the auxiliary wiring at a connection point located in the middle of the first common wiring. The third common wiring is electrically connected to the auxiliary wiring at one end of the third common wiring. The liquid ejection head according to claim 8, characterized in that...

10. The cross-sectional area of the auxiliary wiring is larger than the cross-sectional area of the individual wiring. The liquid ejection head according to claim 1, characterized in that...

11. The common electrode is installed on the surface of the piezoelectric body that is opposite to the surface on the pressure chamber side among the surfaces of the piezoelectric body. The individual electrode is installed on the surface of the piezoelectric body that is on the pressure chamber side among the surfaces of the piezoelectric body. The liquid ejection head according to claim 1, characterized in that...

12. The arrangement direction of the plurality of pressure chambers is defined as the first direction. Among the connection points of the individual wiring and the individual electrodes, a connection point of the common wiring and the common electrode is interposed between a first connection point and a second connection point that are adjacent to each other in the first direction. When a connection point of the common wiring and the common electrode is not interposed between a third connection point and a fourth connection point that are adjacent to each other in the first direction among the connection points of the individual wiring and the individual electrodes. The interval between the first connection point and the second connection point in the first direction. Is larger than the interval between the third connection point and the fourth connection point in the first direction. The liquid ejection head according to claim 1, characterized in that...

13. The liquid ejection head according to any one of claims 1 to 12, And a control device that controls the liquid ejection operation from the liquid ejection head. A liquid ejection device, characterized in that...

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