Liquid ejection head and liquid ejection apparatus

Abstract

The present invention provides a liquid ejection head and a liquid ejection apparatus, and the subject of the present invention is to increase the thickness of a liquid ejection head (1) as compared to a method in which an auxiliary electrode is not provided in the liquid ejection head (1) because of having a structure in which auxiliary electrodes are laminated on a common electrode (Qb) provided in the liquid ejection head (1) according to the prior art. The liquid head (1) includes: a nozzle substrate (21) on which a nozzle (N) that ejects liquid is provided; a pressure chamber substrate (23) on which a plurality of pressure chambers (CV) for applying pressure to the liquid are provided; a piezoelectric element (PZ) comprising 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); and a wiring substrate (4) on which individual wiring (Wc) that applies a voltage to the individual electrodes (Qc), common wiring (Wb) that applies a voltage to the common electrodes (Qb), and auxiliary wiring (Aw) that is electrically connected to the common wiring (Wb) and that reduces the resistance of the common electrodes (Wb) are provided.

Description

Technical Field

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

[0002] There is known a technique for reducing the resistance of a common electrode 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 separately for the plurality of pressure chambers, a common electrode provided commonly for the plurality of pressure chambers, and a piezoelectric body. 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 in a recess of a protective portion in a liquid ejection head.

[0003] However, according to the existing technique, even if it is desired 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 thick and the recess is also made thick, although resistance reduction can be achieved due to a surplus in the height range, there is a problem that the thickness of the liquid ejection head increases accordingly.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-24151 Summary of the Invention

[0005] A liquid ejection head according to one aspect of the present invention is characterized by including: a nozzle substrate on which nozzles for ejecting a liquid are provided; a pressure chamber substrate on which a plurality of pressure chambers for applying pressure to the liquid are provided; a piezoelectric element composed of a piezoelectric body, individual electrodes provided separately for the plurality of pressure chambers, and a common electrode provided commonly for the plurality of pressure chambers; and a wiring substrate on which individual wirings for applying a voltage to the individual electrodes, a common wiring for applying a voltage to the common electrode, and an auxiliary wiring electrically connected to the common wiring and for reducing the resistance of the common electrode are provided.

[0006] In addition, a liquid ejection device according to one aspect of the present invention is characterized by including: the above-described liquid ejection head; and a control device that controls an ejection operation of the liquid performed from the liquid ejection head. Brief Description of the Drawings

[0007] Figure 1 An explanatory diagram showing a liquid ejection device 100 according to the present embodiment.

[0008] Figure 2 An exploded perspective view of the liquid ejection head 1.

[0009] Figure 3 For Figure 2Cross-sectional view taken along line III-III in

[0010] Figure 4 Top view of the liquid ejection head 1.

[0011] Figure 5 is Figure 4 Cross-sectional view taken along line e-E in

[0012] Figure 6 is Figure 4 Cross-sectional view taken along line f-F in

[0013] Figure 7 Structural diagram of the wiring substrate 4.

[0014] Figure 8 Structural diagram of the wiring substrate 4.

[0015] Figure 9 Top view of the liquid ejection head 1A.

[0016] Figure 10 Top view of the liquid ejection head 1B.

[0017] Figure 11 Structural diagram of the wiring substrate 4A.

[0018] Figure 12 Structural diagram of the wiring substrate 4A. Detailed implementation mode

[0019] 1: First implementation mode

[0020] Hereinafter, while referring to Figures 1 to 8 the liquid ejection device 100 according to the first implementation mode will be described.

[0021] 1-1: Outline of the liquid ejection device

[0022] Figure 1 is an explanatory diagram showing the liquid ejection device 100 according to the present implementation mode.

[0023] The liquid ejection device 100 is an inkjet printing device that ejects ink onto the medium PP. The medium PP is typically printing paper, but any printing object such as a resin film or cloth can be used as the medium PP.

[0024] The liquid ejection device 100 includes a liquid container 93 for storing ink. As the liquid container 93, for example, a detachable ink cartridge relative to 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 used. In the liquid container 93, a plurality of inks with different colors are stored.

[0025] The liquid ejection device 100 includes a plurality of liquid ejection heads 1, a control device 7, a conveyance mechanism 91, a moving mechanism 92, and a supply mechanism 94.

[0026] The control device 7 includes, for example, 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.

[0027] Based on the control implemented by the control device 7, the conveyance mechanism 91 conveys the medium PP in the Y1 direction along the Y axis. Hereinafter, the Y1 direction and the Y2 direction opposite to the Y1 direction are collectively referred to as the Y-axis direction. In addition, 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, a case where the X axis, the Y axis, and the Z axis are orthogonal to each other will be described. However, the present invention is not limited to this manner. The X axis, the Y axis, and the Z axis only need to intersect each other.

[0028] Based on the control implemented by the control device 7, the moving mechanism 92 reciprocally moves the plurality of liquid ejection heads 1 in the X1 direction and the X2 direction. The moving mechanism 92 includes a housing 921 that houses the plurality of liquid ejection heads 1, and an endless belt 922 to which the housing 921 is fixed. In addition, the liquid container 93 and the liquid ejection heads 1 may be housed together in the housing 921.

[0029] Based on the control implemented by the control device 7, the supply mechanism 94 supplies the ink stored in the liquid container 93 to the liquid ejection heads 1. In addition, the supply mechanism 94 may, based on the control implemented by the control device 7, supply the ink stored in the liquid container 93 to the liquid ejection heads 1, recover the ink stored in the liquid ejection heads 1, and return the recovered ink to the liquid ejection heads 1.

[0030] The control device 7 supplies a drive signal Com for driving the liquid ejection head 1 and a control signal SI for controlling the liquid ejection head 1 to the liquid ejection head 1. Moreover, the liquid ejection head 1 is driven by the drive signal Com based on the control implemented by the control signal SI, so that the ink is ejected from a part or all of the multiple nozzles N provided in the liquid ejection head 1 in the Z1 direction. That is, the liquid ejection head 1 ejects ink from a part or all of the multiple nozzles N in conjunction with the conveyance of the medium PP implemented by the conveying mechanism 91 and the reciprocating movement of the liquid ejection head 1 implemented by the moving mechanism 92, and the ejected ink is ejected onto the surface of the medium PP, thereby forming a desired image on the surface of the medium PP. In addition, with respect to the nozzles N, Figure 2 And the figure is described later.

[0031] 1-2: Overview of Liquid Ejection Head

[0032] Below, in reference Figure 2 as well as Figure 3 At the same time, the outline of the liquid ejecting head 1 will be described.

[0033] Figure 2 It is an exploded perspective view of the liquid ejecting head 1. Figure 3 for Figure 2 Cross-sectional view along line III-III.

[0034] like Figure 2 as well as Figure 3 As shown, the liquid ejection head 1 includes a nozzle substrate 21 , compliance sheets CS1 and CS2 , a communication plate 22 , a pressure chamber substrate 23 , a vibration plate 24 , a sealing substrate 25 , a flow path formation substrate 26 , and a wiring substrate 4 .

[0035] like Figure 2 As shown, the nozzle substrate 21 is a plate-shaped component that is long and narrow in the Y-axis direction and extends approximately parallel to the XY plane. Here, "approximately parallel" is a concept that includes not only the case of being completely parallel but also the case where the error can be considered as parallel. In the present embodiment, "approximately parallel" refers to the concept that includes the case where the error of about 10% can be considered as parallel. The nozzle substrate 21 is manufactured by processing a single crystal silicon substrate using semiconductor manufacturing technology such as etching, for example, but any known material and manufacturing method can be used in the manufacture of the nozzle substrate 21.

[0036] A plurality of nozzles N are formed on the nozzle substrate 21. Here, the nozzle N refers to a through-hole provided on 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 and configured to extend in the Y-axis direction, and a plurality of nozzles N2 arranged and configured to extend in the Y-axis direction at a position in the X2 direction when viewed from the plurality of nozzles N1. Hereinafter, the plurality of nozzles N1 extending in the Y-axis direction are referred to as nozzle row Ln1, and the plurality of nozzles N2 extending in the Y-axis direction are referred to as nozzle row Ln2. In addition, hereinafter, the nozzle row Ln1 and the nozzle row Ln2 may be collectively referred to as nozzle row Ln.

[0037] As Figure 2 and Figure 3 shown, a communication plate 22 is provided at a position in the Z2 direction when viewed from the nozzle substrate 21. The communication plate 22 is a plate-shaped member that is long and narrow 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-crystalline silicon substrate using semiconductor manufacturing technology, but known materials and manufacturing methods can also be arbitrarily adopted in the manufacturing of the communication plate 22.

[0038] An ink flow path is formed on the communication plate 22. Specifically, on the communication plate 22, one supply flow path BA1 is provided to extend in the Y-axis direction (the Y-axis direction becomes the length direction), and one supply flow path BA2 is provided to extend in the Y-axis direction at a position in the X2 direction when viewed from the supply flow path BA1. In addition, on 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.

[0039] Among them, the connection flow path BK1 communicates with the supply flow path BA1 and is provided to extend in the Z-axis direction (the Z-axis direction becomes the length direction) at a position in the X2 direction when viewed from the supply flow path BA1. The communication flow path BR1 is provided to extend in the Z-axis direction at a position in the X2 direction when viewed from the connection flow path BK1. The communication flow path BR1 communicates with the corresponding nozzle N1. The connection flow path BK2 communicates with the supply flow path BA2 and is provided to extend in the Z-axis direction at a position in the X1 direction when viewed from the supply flow path BA2. The communication flow path BR2 is provided to extend in the Z-axis direction at a position in the X1 direction when viewed from the connection flow path BK2 and at a position in the X2 direction when viewed from the communication flow path BR1. The communication flow path BR2 communicates with the corresponding nozzle N2.

[0040] In addition, hereinafter, the supply flow paths BA1 and BA2 may sometimes be collectively referred to as the supply flow path BA. Further, hereinafter, the connection flow paths BK1 and BK2 may sometimes be collectively referred to as the connection flow path BK. Further, hereinafter, the communication flow paths BR1 and BR2 may sometimes be collectively referred to as the communication flow path BR.

[0041] As Figure 2 and Figure 3 shown, 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-like member that is elongated 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-crystalline silicon substrate using semiconductor manufacturing technology, but known materials and manufacturing methods can also be arbitrarily adopted in the manufacture of the pressure chamber substrate 23.

[0042] Flow paths for ink are formed on the pressure chamber substrate 23. Specifically, on the pressure chamber substrate 23, 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. Among them, 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 becomes the length direction). When viewed in the Z-axis 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. In addition, hereinafter, the pressure chambers CV1 and CV2 may sometimes be collectively referred to as the pressure chamber CV. Further, the Y-axis direction, which is the arrangement direction of the pressure chambers CV, is an example of the "first direction".

[0043] As Figure 2 and Figure 3 shown, 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 elongated in the Y-axis direction and extends substantially parallel to the XY plane, and is a member that can vibrate elastically. In addition, in the present embodiment, the surface in the Z2 direction of the two surfaces of the diaphragm 24 having the Z-axis direction as the normal direction is formed of a non-conductive member. For example, the diaphragm 24 may be a diaphragm having 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.

[0044] As Figure 2 and Figure 3As shown, a plurality of piezoelectric elements PZ1 corresponding to the plurality of pressure chambers CV1, and a plurality of piezoelectric elements PZ2 corresponding to the plurality of pressure chambers CV2 are provided at positions close to the Z2 direction when viewed from the vibration plate 24. In the following, the piezoelectric elements PZ1 and the piezoelectric elements PZ2 are sometimes collectively referred to as piezoelectric elements PZ. The piezoelectric element PZ is constructed in a manner including a piezoelectric body Qm, individual electrodes Qc individually provided for the plurality of pressure chambers CV, and a common electrode Qb commonly provided for the plurality of pressure chambers CV. In addition, the piezoelectric body Qm, the individual electrodes Qc, and the common electrode Qb are described in detail below. Figure 4 as well as Figure 5 The piezoelectric element PZ is a passive element that is deformed according to the potential change of the drive signal Com. In other words, the piezoelectric element PZ is an example of an energy conversion element that converts the electrical energy of the drive signal Com into kinetic energy. Specifically, the piezoelectric element PZ is driven and deformed according to the potential change of the drive signal Com. The vibration plate 24 vibrates in conjunction with the deformation of the piezoelectric element PZ. When the vibration plate 24 vibrates, the pressure in the pressure chamber CV changes. And by changing the pressure in the pressure chamber CV, the ink filled into the interior of the pressure chamber CV is ejected from the nozzle N through the connecting flow channel BR.

[0045] like Figure 2 as well as Figure 3 As shown in FIG. 1 , a sealing substrate 25 for protecting the plurality of piezoelectric elements PZ1 and the plurality of piezoelectric elements PZ2 is provided at a position close to the Z2 direction when viewed from the pressure chamber substrate 23. The sealing substrate 25 is a plate-shaped member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The sealing substrate 25 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology, but any known material and manufacturing method may be used in the manufacturing of the sealing substrate 25.

[0046] On the surface in the Z1 direction among the two surfaces of the sealed substrate 25 with the Z-axis direction as the normal direction, there are provided a recess for covering a plurality of piezoelectric elements PZ1 and a recess for covering a plurality of piezoelectric elements PZ2. Hereinafter, the sealed space formed between the diaphragm 24 and the sealed substrate 25 and covering the plurality of piezoelectric elements PZ1 is referred to as the sealed space SP1, and the sealed space formed between the diaphragm 24 and the sealed substrate 25 and covering the plurality of piezoelectric elements PZ2 is referred to as the sealed space SP2. In addition, hereinafter, the sealed space SP1 and the sealed space SP2 may be collectively referred to as the sealed space SP. The sealed 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. In addition, hereinafter, when the sealed substrate 25 is viewed from above in the Z1 direction, the portion that becomes the side wall of the sealed space SP1 is referred to as the side wall WL1, and the portion that becomes the side wall of the sealed space SP2 is referred to as the side wall WL2. In addition, hereinafter, the side wall WL1 and the side wall WL2 may be collectively referred to as the side wall WL. In addition, the side wall WL is an example of a "wall portion".

[0047] A through hole 250 is provided on the sealed substrate 25. The through hole 250 is a hole that is located between the sealed space SP1 and the sealed space SP2 when the sealed substrate 25 is viewed in the Z1 direction and penetrates from the surface in the Z1 direction of the sealed substrate 25 to the surface in the Z2 direction of the sealed substrate 25. A wiring substrate 4 is inserted through the through hole 250.

[0048] As Figure 2 and Figure 3 shown, a flow path forming substrate 26 is provided at a position closer to the Z2 direction when viewed from the communication plate 22. The flow path forming substrate 26 is a plate-like member that is long and narrow 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 can also be arbitrarily adopted in the manufacture of the flow path forming substrate 26.

[0049] On the flow channel forming substrate 26, flow channels for ink are formed. Specifically, on the flow channel forming substrate 26, a supply flow channel BB1 and a supply flow channel BB2 are formed. Among them, the supply flow channel BB1 communicates with the supply flow channel BA1 and is arranged in a manner extending in the Y-axis direction at a position in the Z2 direction when observed from the supply flow channel BA1. The supply flow channel BB2 communicates with the supply flow channel BA2 and is arranged in a manner extending in the Y-axis direction at a position in the Z2 direction when observed from the supply flow channel BA2 and at a position in the X2 direction when observed from the supply flow channel BB1. Additionally, hereinafter, the supply flow channel BB1 and the supply flow channel BB2 may sometimes be collectively referred to as the supply flow channel BB.

[0050] On the flow channel forming substrate 26, an inlet HL1 communicating with the supply flow channel BB1 and an inlet HL2 communicating with the supply flow channel BB2 are provided.

[0051] Moreover, in the supply flow channel BB1, ink is supplied from the liquid container 93 via the inlet HL1. The ink supplied to the supply flow channel BB1 from the liquid container 93 via the inlet HL1 flows into the supply flow channel BA1. A part of the ink flowing into the supply flow channel BA1 is filled into the pressure chamber CV1 via the connection flow channel BK1. When the piezoelectric element PZ1 is driven by the drive signal Com, a part of the ink filled into the pressure chamber CV1 is ejected from the nozzle N1 via the communication flow channel BR1.

[0052] In addition, in the supply flow channel BB2, ink is supplied from the liquid container 93 via the inlet HL2. The ink supplied to the supply flow channel BB2 from the liquid container 93 via the inlet HL2 flows into the supply flow channel BA2. A part of the ink flowing into the supply flow channel BA2 is filled into the pressure chamber CV2 via the connection flow channel BK2. When the piezoelectric element PZ2 is driven by the drive signal Com, a part of the ink filled into the pressure chamber CV2 is ejected from the nozzle N2 via the communication flow channel BR2.

[0053] A through hole 260 is provided on the flow channel forming substrate 26. The through hole 260 is a hole that is located between the supply flow channel BB1 and the supply flow channel BB2 when the flow channel forming substrate 26 is observed in the Z1 direction and penetrates from the surface of the flow channel forming substrate 26 in the Z1 direction to the surface of the flow channel forming substrate 26 in the Z2 direction. A wiring substrate 4 is inserted through the through hole 260.

[0054] As Figure 2 and Figure 3As shown, a wiring board 4 is mounted on the surface of the vibration plate 24 in the Z2 direction. The wiring board 4 is a component for electrically connecting the liquid ejection head 1 and the control device 7. As the wiring board 4, for example, a flexible wiring board such as an FPC or an FFC is preferably used. Here, FPC is an abbreviation for Flexible Printed Circuit, and FFC is an abbreviation for Flexible Flat Cable. An integrated circuit 40 is mounted on the wiring board 4. The integrated circuit 40 is a circuit that switches whether to supply a drive signal Com to the piezoelectric element PZ based on the control implemented by the control signal SI.

[0055] As Figure 3 shown, in the XZ plane, the wiring board 4 has an L-shaped cross-section formed by being bent along the bending line BL. The wiring board 4 includes a first substrate portion LS extending in the Z2 direction from the bending line BL in the YZ plane, and a second substrate portion SS extending in the X1 direction from the bending line BL in the XY plane. In addition, the wiring board 4 includes a first surface FC1 and a second surface FC2.

[0056] The first surface FC1 is composed of the surface in the X2 direction of the first substrate portion LS and the surface in the Z1 direction of the second substrate portion SS, and the second surface FC2 is composed of the surface in the X1 direction of the first substrate portion LS and the surface in the Z2 direction of the second substrate portion SS. The second surface FC2 is the back surface of the first surface FC1.

[0057] As Figure 2 and Figure 3 shown, at a position in the Z1 direction when viewed from the communication plate 22, a plastic sheet CS1 is provided so as to close the supply channel BA1 and the connection channel BK1, and a plastic sheet CS2 is provided so as to close the supply channel BA2 and the connection channel BK2. Hereinafter, the plastic sheet CS1 and the plastic sheet CS2 may be collectively referred to as the plastic sheet CS. The plastic sheet CS is a plate-like component that is long and narrow in the Y-axis direction and extends substantially parallel to the XY plane. The plastic sheet CS is formed of an elastic material to absorb pressure fluctuations of the ink in the supply channel BA and the connection channel BK.

[0058] 1-3: Structure of the electrodes

[0059] Figure 4 FIG. is a top view of the liquid ejection head 1 when viewed from above in the Z1 direction. Hereinafter, while referring to Figure 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.

[0060] 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.

[0061] As Figure 4 shown, when the liquid ejection head 1 is viewed from above in the Z1 direction, a plurality of pressure chambers CV1, a plurality of piezoelectric elements Qm1, a plurality of first individual electrodes Qc1, and a first common electrode Qb1 are provided at positions overlapping with a sealing space SP1 which is a space inside the side wall WL1 of the sealing substrate 25. The plurality of pressure chambers CV1 are provided in one-to-one correspondence with the plurality of nozzles N1. However, one nozzle N1 may be shared by a plurality of pressure chambers CV1, or a plurality of nozzles N1 may be provided for one pressure chamber CV1. In addition, the plurality of piezoelectric elements Qm1 are provided in one-to-one correspondence with the plurality of pressure chambers CV1. In addition, the plurality of first individual electrodes Qc1 are provided in one-to-one correspondence with the plurality of pressure chambers CV1. The first common electrode Qb1 is commonly provided for the plurality of pressure chambers CV1. More specifically, the first common electrode Qb1 is provided so as to overlap with the plurality of pressure chambers CV1 when the liquid ejection head 1 is viewed from above in the Z1 direction. However, the first common electrode Qb1 may also be provided so that each of the plurality of pressure chambers CV1 has a portion that does not overlap with the first common electrode Qb1 when the liquid ejection head 1 is viewed from above in the Z1 direction. The sealing substrate 25 is provided so as to overlap with the plurality of pressure chambers CV1 when viewed in the Z-axis direction.

[0062] Similarly, when the liquid ejection head 1 is viewed from above in the Z1 direction, at a position overlapping with the sealing space SP2 which is the space inside the side wall WL2 of the sealing substrate 25, a plurality of pressure chambers CV2, a plurality of piezoelectric elements Qm2, a plurality of second individual electrodes Qc2, and a second common electrode Qb2 are provided. The plurality of pressure chambers CV2 are provided in a one-to-one correspondence with the plurality of nozzles N2. However, one nozzle N2 may be shared by a plurality of pressure chambers CV2, or a plurality of nozzles N2 may be provided for one pressure chamber CV2. In addition, the plurality of piezoelectric elements Qm2 are provided in a one-to-one correspondence with the plurality of pressure chambers CV2. In addition, the plurality of second individual electrodes Qc2 are provided in a one-to-one correspondence with the plurality of pressure chambers CV2. The second common electrode Qb2 is commonly provided for the plurality of pressure chambers CV2. More specifically, the second common electrode Qb2 is provided so as to overlap with the plurality of pressure chambers CV2 when the liquid ejection head 1 is viewed from above in the Z1 direction. However, the second common electrode Qb2 may also be provided so that each of the plurality of pressure chambers CV2 has a portion that does not overlap with the second common electrode Qb2 when the liquid ejection head 1 is viewed from above in the Z1 direction. The sealing substrate 25 is provided so as to overlap with the plurality of pressure chambers CV2 when viewed in the Z-axis direction.

[0063] The first connection electrode pair Qj1 electrically connects the first common wiring Wb1, which will be described later and is provided on the wiring substrate 4, and the first common electrode Qb1. In addition, the first connection electrode pair Qj1 electrically connects the first common wiring Wb1 and the second common electrode Qb2. The first common wiring Wb1 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. In addition, the first connection electrode pair Qj1 electrically connects the first common electrode Qb1 and the second common electrode Qb2 at the end portions in the Y2 direction in the Y-axis direction of the first common electrode Qb1 and the second common electrode Qb2, respectively.

[0064] The second connection electrode pair Qj2 electrically connects the second common wiring Wb2, which will be described later and is provided on the wiring substrate 4, and the first common electrode Qb1. In addition, the second connection electrode pair 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. In addition, the second connection electrode pair 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 the first common electrode Qb1 and the second common electrode Qb2, respectively.

[0065] 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.

[0066] In addition, in the above-described embodiment, the common electrode Qb has one first connection electrode Qj1, and this one first connection electrode Qj1 electrically connects the first common electrode Qb1 and the second common electrode Qb2. However, as another method, the common electrode Qb may also have 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 the two first connection electrodes Qj1 separately.

[0067] Similarly, in the above-described embodiment, the common electrode Qb has one second connection electrode Qj2, and this one second connection electrode Qj2 electrically connects the first common electrode Qb1 and the second common electrode Qb2. However, as another method, the common electrode Qb may also have 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 the two second connection electrodes Qj2 separately.

[0068] In addition, regarding the first common wiring Wb1 and the second common wiring Wb2, they will be described later by referring to Figure 7 and will be described later.

[0069] In addition, the third connection electrode Qj3 electrically connects the third common wiring Wb3, which will be described later and is provided on the wiring substrate 4, and the first common electrode Qb1. In addition, 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. Regarding the third common wiring Wb3, it will be described later by referring to Figure 7 and will be described later.

[0070] In addition, in the present embodiment, the following situation is envisaged, that is, 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 this manner. Between the first connection electrode Qj1 and the second connection electrode Qj2, one third connection electrode Qj3 may also be provided.

[0071] In addition, the common electrode Qb is formed of a conductive material. Specifically, as the material of the common electrode Qb, 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 used.

[0072] When the liquid ejection head 1 is viewed from above in the Z1 direction, the piezoelectric body Qm1 is provided so as to overlap with the pressure chamber CV1. However, when the liquid ejection head 1 is viewed from above in the Z1 direction, it may also be provided in such a manner that a part of the pressure chamber CV1 does not overlap with the piezoelectric body Qm1. In Figure 4 In the example shown, when the liquid ejection head 1 is viewed from above in the Z1 direction, the piezoelectric body Qm1 is provided in such a manner that the entire piezoelectric body Qm1 is included in the pressure chamber CV1 corresponding to the piezoelectric body Qm1.

[0073] 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.

[0074] In addition, the piezoelectric body Qm1 and the piezoelectric body Qm2 are formed of, for example, a perovskite structure crystal film of a ferroelectric ceramic material that exhibits an electromechanical conversion effect, that is, a so-called perovskite-type crystal. Specifically, as the materials of the piezoelectric body Qm1 and the piezoelectric body Qm2, for example, ferroelectric piezoelectric materials such as lead zirconate titanate, or materials 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 used. More specifically, as the materials of the piezoelectric body Qm1 and the piezoelectric body Qm2, for example, lead titanate, lead zirconate titanate, lead zirconate, lanthanum lead titanate, lanthanum lead zirconate titanate, or lead magnesium niobium zirconate titanate can be used.

[0075] As described above, on the liquid ejection head 1, a plurality of first individual electrodes Qc1 are provided in a one-to-one correspondence with the plurality of pressure chambers CV1. Each first individual electrode Qc1 is connected to an individual wiring Wc provided on the wiring substrate 4. In the individual wiring Wc, a drive signal Com is supplied from the control device 7. As a result, a drive signal Com is supplied to each first individual electrode Qc1. In addition, regarding the individual wiring Wc, it will be described later by referring to Figure 7 and will be described later.

[0076] Similarly, on the liquid ejection head 1, a plurality of second individual electrodes Qc2 are provided in one-to-one correspondence with the plurality of pressure chambers CV2. Each second individual electrode Qc2 is connected to an individual wiring Wc provided on the wiring substrate 4. As described above, 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 second individual electrode Qc2.

[0077] In addition, the individual electrode Qc is formed of a conductive material. Specifically, as the material of the individual electrode Qc, for example, a metal such as platinum, iridium, gold, or titanium, or a conductive metal oxide such as indium tin oxide abbreviated as ITO can be used as the conductive material.

[0078] In addition, in Figure 4 , for ease of explanation, the end portion on the Y2 side of the wiring substrate 4 is located in the Y2 direction compared to the end portions on the Y2 side of the first common electrode Qb1 and the second common electrode Qb2 in the Y-axis direction. However, in the Y-axis direction, the end portion on the Y2 side of the wiring substrate 4 may be located at the same position as the end portions on the Y2 side of the first common electrode Qb1 and the second common electrode Qb2, or may be located in the Y1 direction compared to the end portions on the Y2 side of the first common electrode Qb1 and the second common electrode Qb2.

[0079] Similarly, in Figure 4 , the end portion on the Y1 side of the wiring substrate 4 is located in the Y1 direction compared to the end portions on the Y1 side of the first common electrode Qb1 and the second common electrode Qb2 in the Y-axis direction. However, the end portion on the Y1 side of the wiring substrate 4 may be located at the same position as the end portions on the Y1 side of the first common electrode Qb1 and the second common electrode Qb2, or may be located in the Y2 direction compared to the end portions on the Y1 side of the first common electrode Qb1 and the second common electrode Qb2.

[0080] In addition, in Figure 4 , the first connection electrode Qj1, the second connection electrode Qj2, and the third connection electrode Qj3 are in a straight line shape extending in the X-axis direction. However, in the above case, at least one of these electrodes may be disposed obliquely with respect to the X-axis direction, or may be in a shape bent in the XY plane.

[0081] 1-4: Structure near the first individual electrode Qc1

[0082] Figure 5 For Figure 4 is a cross-sectional view of the e-E line in

[0083] As in Figure 5As shown, on the surface in the Z2 direction among the two surfaces of the vibration plate 24 having the Z-axis direction as the normal direction, a first common electrode Qb1, a first individual electrode Qc1, a piezoelectric body Qm1, and a sealing substrate 25 are formed.

[0084] Hereinafter, the surface in the Z2 direction among the two surfaces of the piezoelectric body Qm1 having the Z-axis direction as the normal direction is referred to as surface PL1. In addition, the surface in the Z1 direction among the two surfaces of the piezoelectric body Qm1 having the Z-axis direction as the normal direction is referred to as surface PL2. In addition, the surface in the X1 direction among the inclined surfaces of the piezoelectric body Qm1 is referred to as surface PL3, and the surface in the X2 direction is referred to as surface PL4. In addition, the surface in the Z2 direction among the two surfaces of the vibration plate 24 having the Z-axis direction as the normal direction is referred to as surface QL1.

[0085] On the surface PL1 of the piezoelectric body Qm1, the surface PL3, and the surface QL1 of the vibration plate 24, a first common electrode Qb1 is formed. In other words, the first common electrode Qb1 is provided on the surface of the piezoelectric body Qm1 that is on the opposite side of the pressure chamber CV1, i.e., surface PL1. The end portion of the first common electrode Qb1 in the X2 direction is located on the surface PL1 and is located in the X1 direction compared to the surface PL4. In addition, the end portion of the first common electrode Qb1 in the X1 direction is located on the surface QL1 and is located inside the sealing substrate 25.

[0086] A first individual electrode Qc1 is formed on the surface PL2 of the piezoelectric body Qm1. In other words, the first individual electrode Qc1 is provided on the surface of the piezoelectric body Qm1 that is on the pressure chamber CV1 side, i.e., surface PL2. The end portion of the first individual electrode Qc1 in the X1 direction is located in the X2 direction compared to the surface PL3. In addition, the first individual electrode Qc1 extends to the outside of the sealing substrate 25 in the X2 direction. 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.

[0087] 1 - 5: Structure near the first connection electrode Qj1

[0088] Figure 6 is Figure 4 a cross-sectional view of the f - F line in

[0089] As Figure 6 shown, on the surface QL1 of the vibration plate 24, a first connection electrode Qj1 and a common electrode Qb are formed. The first connection electrode Qj1 and the common electrode Qb are in Figure 6They are interconnected on the connection line CL shown. The end portion of the common electrode Qb in the X1 direction is located on the surface QL1 and 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 the first common wiring Wb1 provided on the first surface FC1 of the wiring substrate 4 outside the sealing substrate 25.

[0090] In addition, in Figure 4 the cross-section of the g-G line, the second connection electrode Qj2 is electrically connected to the second common wiring Wb2 provided on the first surface FC1 inside the second substrate portion SS. Since this structure is the same as that of Figure 6 the cross-section of the f-F line shown, except for replacing the first connection electrode Qj1 with the second connection electrode Qj2 and replacing the first common wiring Wb1 with the second common wiring Wb2, the illustration thereof is omitted.

[0091] Furthermore, in Figure 4 the cross-section of the h-H line, the third connection electrode Qj3 is electrically connected to the third common wiring Wb3 provided on the first surface FC1 inside the second substrate portion SS. Since this structure is the same as that of Figure 6 the cross-section of the f-F line shown, except for replacing the first connection electrode Qj1 with the third connection electrode Qj3 and replacing the first common wiring Wb1 with the third common wiring Wb3, the illustration thereof is omitted.

[0092] 1-6: Structure of the wiring substrate 4

[0093] Figure 7 And Figure 8 is an explanatory diagram for explaining various wirings provided on the wiring substrate 4. In addition, hereinafter, the direction from the piezoelectric element PZ toward the control device 7 in the extending direction of various wirings in the wiring substrate 4 is referred to as the FX1 direction, and the opposite direction of the FX1 direction is referred to as the FX2 direction. In addition, the FX1 direction and the FX2 direction are referred to as the FX direction. In the first substrate portion LS on the FX1 side compared with the folding line BL, the FX1 direction coincides with the Z2 direction. On the other hand, in the second substrate portion SS on the FX2 side compared with the folding line BL, the FX2 direction coincides with the X1 direction.

[0094] In addition, hereinafter, the direction from the first surface FC1 toward the second surface FC2 in the wiring substrate 4 is referred to as the FZ1 direction, and the direction opposite to the FZ1 direction is referred to as the FZ2 direction. Further, the FZ1 direction and the FZ2 direction are referred to as the FZ direction. In the first substrate portion LS on the FX1 side as compared with the folding 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 as compared with the folding line BL, the FZ1 direction coincides with the Z2 direction, and the FZ2 direction coincides with the Z1 direction.

[0095] In addition, hereinafter, the direction orthogonal to both the FX direction and the FZ direction in the wiring substrate 4 is referred to as the FY direction. The direction coinciding with the Y1 direction in the FY direction is referred to as the FY1 direction, and the direction opposite to the FY1 direction and coinciding with the Y2 direction is referred to as the FY2 direction.

[0096] Figure 7 It is a structural diagram of the wiring substrate 4 for explaining the arrangement of wirings and electronic components provided on the first surface FC1 when observing the first surface FC1 of the wiring substrate 4 from the FZ2 side toward the FZ1 side.

[0097] Figure 8 It is a structural diagram of the wiring substrate 4 for explaining the arrangement of wirings provided on the second surface FC2 when observing the second surface FC2 of the wiring substrate 4 from the FZ1 side toward the FZ2 side. In Figure 8 order to facilitate the explanation, a part of the wirings and electronic components provided on the first surface FC1 is shown by a dashed line.

[0098] As Figure 7 shown, on the first surface FC1 of the wiring substrate 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 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 a 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. In addition, hereinafter, the wirings including the above-described first common wiring Wb1, second common wiring Wb2, and third common wirings Wb3 may be referred to as common wirings Wb.

[0099] In addition, 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 this mode. One third common wiring Wb3 may be provided between the first common wiring Wb1 and the second common wiring Wb2.

[0100] The first common wiring Wb1 includes a first common wiring connection portion Kb1 provided on the first surface FC1 within the second substrate portion SS, and a first common wiring extension portion Lb1 provided on the first surface FC1 within the first substrate portion LS.

[0101] The first common wiring extension portion Lb1 is electrically connected to a power supply circuit of a control device 7 (not shown), and a reference potential VBS is supplied from this power supply circuit. Therefore, the first common wiring Wb1 including the first common wiring extension portion Lb1 is set to the reference potential VBS. In addition, the first common wiring connection portion Kb1 included 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.

[0102] The second common wiring Wb2 includes a second common wiring connection portion Kb2 provided on the first surface FC1 within the second substrate portion SS, and a second common wiring extension portion Lb2 provided on the first surface FC1 within the first substrate portion LS.

[0103] The second common wiring extension portion Lb2 is electrically connected to a power supply circuit of a control device 7 (not shown), and a reference potential VBS is supplied from this power supply circuit. Therefore, the second common wiring Wb2 including the second common wiring extension portion Lb2 is set to the reference potential VBS. In addition, the second common wiring connection portion Kb2 included 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.

[0104] The third common wiring Wb3 includes a third common wiring connection portion Kb3 provided on the first surface FC1 within the second substrate portion SS, and a third common wiring extension portion Lb3 provided on the first surface FC1 within the first substrate portion LS. The third common wiring connection portion Kb3 included in the third common wiring Wb3 is connected to the third connection electrode Qj3. In addition, 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 within the first substrate portion LS.

[0105] In addition, on the first surface FC1 of the wiring substrate 4, a plurality of individual wirings Wc, one or more first supply wirings Wd, and one or more second supply wirings We are also provided. In addition, in the present embodiment, as an example, it is assumed that two first supply wirings Wd and one second supply wiring We are arranged on the first surface FC1 of the wiring substrate 4.

[0106] The individual wiring Wc includes an individual wiring connection portion Kc provided on the first surface FC1 within the second substrate portion SS, and an individual wiring extension portion Lc provided on the first surface FC1 within the first substrate portion LS.

[0107] The individual wiring extension portion Lc is connected to the integrated circuit 40.

[0108] The plurality of individual wirings Wc are provided in a one-to-one correspondence with the plurality of individual electrodes Qc. The individual wiring connection portion Kc is connected to the individual electrode Qc that is provided corresponding to the individual wiring Wc having the individual wiring connection portion Kc among the plurality of individual electrodes Qc.

[0109] One or more first supply wirings Wd are connected to the integrated circuit 40 within the first substrate portion LS. In addition, one or more first supply wirings Wd are connected to the control device 7 at the end portion on the FX1 side. In the integrated circuit 40, a drive signal Com is supplied from the control device 7 via one or more first supply wirings Wd.

[0110] One or more second supply wirings We are connected to the integrated circuit 40 within the first substrate portion LS. In addition, one or more second supply wirings We are connected to the control device 7 at the end portion on the FX1 side. In the integrated circuit 40, a control signal SI is supplied from the control device 7 via one or more second supply wirings We.

[0111] 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.

[0112] In Figure 7On the first surface FC1 of the wiring substrate 4 shown, the first common wiring Wb1 is connected to the first connection electrode Qj1 at a position closer to the FY2 side, which is one side along the FY direction, than the connection positions of the plurality of individual electrodes Qc and the plurality of individual wirings Wc. Further, on this first surface FC1, the second common wiring Wb2 is connected to the second connection electrode Qj2 at a position closer to the FY1 side, which is the other side along the FY direction, than the connection positions of the plurality of individual electrodes Qc and the plurality of individual wirings Wc. Additionally, in Figure 7 for ease of explanation, the first common wiring Wb1, the second common wiring Wb2, and the plurality of individual wirings Wc are each made into a straight line extending in the FX direction, but at least one of these wirings may be disposed obliquely with respect to the FX direction and may also have a bent shape within the first surface FC1.

[0113] In Figure 8 an auxiliary wiring Aw is provided on the second surface FC2 of the wiring substrate 4. More specifically, the auxiliary wiring Aw is provided on the second surface FC2 within the first substrate portion LS of the wiring substrate 4. As will be described later, the auxiliary wiring Aw is provided to reduce the resistance of the common electrode Qb.

[0114] When the wiring substrate 4 is viewed from above in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 are provided at overlapping positions. Further, when the wiring substrate 4 is viewed from above in the FZ direction, 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 provided at overlapping positions. Additionally, in the first substrate portion LS, the cross-sectional area of the auxiliary wiring Aw in a cross-section orthogonal to the FX direction is larger than the cross-sectional area of the individual wiring Wc in a cross-section orthogonal to the FX direction. Also, the auxiliary wiring Aw is not electrically connected to the individual wiring Wc.

[0115] On the wiring substrate 4, a first through hole Jb1, a second through hole Jb2, and a plurality of third through holes Jb3 are provided. The plurality of third through holes Jb3 are provided in one-to-one correspondence with the plurality of third common wirings Wb3. Additionally, hereinafter, the first through hole Jb1, the second through hole Jb2, and the third through holes Jb3 may be collectively referred to as through holes Jb.

[0116] When the wiring substrate 4 is viewed from above in the FZ direction, the first through-hole Jb1 is provided at a position overlapping with the first common wiring extension portion Lb1 included in the first common wiring Wb1. The first common wiring Wb1 is electrically connected to the auxiliary wiring Aw via a conductor passing through the first through-hole Jb1 at a first connection point Jt1 located at a position overlapping with the first through-hole Jb1 when viewed in the FZ direction. 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.

[0117] When the wiring substrate 4 is viewed from above in the FZ direction, the second through-hole Jb2 is provided at a position overlapping with the second common wiring extension portion Lb2 included in the second common wiring Wb2. The second common wiring Wb2 is electrically connected to the auxiliary wiring Aw via a conductor passing through the second through-hole Jb2 at a second connection point Jt2 located at a position overlapping with the second through-hole Jb2 when viewed in the FZ direction. 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.

[0118] As a result, the auxiliary wiring Aw electrically connects the first common wiring Wb1 and the second common wiring Wb2.

[0119] When the wiring substrate 4 is viewed from above in the FZ direction, the third through-hole Jb3 is provided at a position overlapping with an end portion of the third common wiring Wb3. The third common wiring Wb3 is electrically connected to the auxiliary wiring Aw via a conductor passing through the third through-hole Jb3 at a third connection point Jt3 located at a position overlapping with the third through-hole Jb3 when viewed in the FZ direction. As described above, since the third common wiring connection portion Kb3 included 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.

[0120] In addition, hereinafter, 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.

[0121] 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.

[0122] As described above, according to the existing technology, since there is a structure in which the 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 compared to the method in which the auxiliary electrode is not provided in the liquid ejection head.

[0123] In contrast, in the liquid ejection head 1 according to the present embodiment, the auxiliary electrode is not laminated on the common electrode Qb, but the auxiliary wiring Aw is provided on the wiring substrate 4 existing outside the sealing substrate 25, so that it is no longer necessary to increase the thickness of the liquid ejection head 1.

[0124] As a further problem, when the common electrode Qb has a high resistance, there is a tendency to increase the occurrence of electrical crosstalk compared to the case where the common electrode Qb has a low resistance. Specifically, when the common electrode Qb has a high resistance, the potential of the common electrode Qb is more likely to be affected by the potential change of the driving signal Com supplied to the individual electrode Qc compared to the case where the common electrode Qb has a low resistance. Since when the potential of the common electrode Qb changes, the voltage applied between the common electrode Qb and the individual electrode Qc constituting the piezoelectric element PZ changes from the desired voltage, there may sometimes be a problem such as a decrease in printing quality.

[0125] In the liquid ejection head 1 according to the present embodiment, by providing the auxiliary wiring Aw on the wiring substrate 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.

[0126] In addition, when wiring such as an auxiliary electrode is provided near the piezoelectric element PZ, the reliability or characteristics of the piezoelectric element PZ may be adversely affected by the influence of electroplating used in the wiring. In the liquid ejection head 1 according to the present embodiment, since wiring such as an auxiliary electrode is not provided near the piezoelectric element PZ, such an adverse effect can be suppressed.

[0127] 1-7: Effects achieved by the first embodiment

[0128] 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. On the nozzle substrate 21, nozzles N for ejecting ink are provided. On the pressure chamber substrate 23, a plurality of pressure chambers CV for applying pressure to the ink are provided. The piezoelectric element PZ is composed of a piezoelectric body Qm, individual electrodes Qc provided individually for the plurality of pressure chambers CV, and a common electrode Qb provided commonly for the plurality of pressure chambers CV. On the wiring substrate 4, 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 and used to reduce the resistance of the common electrode Qb are provided.

[0129] By configuring the liquid ejection head 1 as described above, that is, by providing the auxiliary wiring Aw on the wiring substrate 4 instead of laminating an auxiliary electrode on the common electrode Qb, the resistance of the common electrode Qb can be reduced without increasing the thickness of the liquid ejection head 1.

[0130] In addition, 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 behind the first surface FC1 of the wiring substrate 4.

[0131] By configuring the liquid ejection head 1 as described above, the size of the wiring substrate 4 can be suppressed as compared with a configuration 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.

[0132] In addition, 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.

[0133] By configuring the liquid ejection head 1 as described above, since the common wiring Wb and the auxiliary wiring Aw can be provided on different surfaces of the wiring substrate 4, the size of the wiring substrate 4 can be suppressed.

[0134] In addition, in the liquid ejection head 1 according to this embodiment, an integrated circuit 40 connected to the individual wiring Wc is also provided on the wiring substrate 4. When the wiring substrate 4 is viewed from above, the auxiliary wiring Aw and the integrated circuit 40 are provided at overlapping positions.

[0135] By configuring the liquid ejection head 1 as described above, since the auxiliary wiring Aw and the integrated circuit 40 are provided at overlapping positions, a shielding effect is achieved.

[0136] 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.

[0137] By configuring the liquid ejection head 1 to have the above-described structure, noise generated in the integrated circuit 40 is suppressed.

[0138] 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 set as the first direction, the first common wiring Wb1 is connected to the common electrode Qb on the side along the first direction compared to the connection position with 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 compared to the connection position with the individual electrode Qc and the individual wiring Wc.

[0139] By configuring the liquid ejection head 1 to have the above-described structure, noise generated in the integrated circuit 40 is suppressed.

[0140] In addition, the liquid ejection head 1 according to the present embodiment further includes a third common wiring Wb3. When the arrangement direction of the plurality of pressure chambers CV is set as the first direction, the third common wiring Wb3 is disposed between the first common wiring Wb1 and the second common wiring Wb2 in the first direction and electrically connects the common electrode Qb and the auxiliary wiring Aw.

[0141] By configuring the liquid ejection head 1 to have the above-described structure, a voltage drop occurring near the center in the arrangement direction of the plurality of pressure chambers CV is suppressed in the common electrode Qb.

[0142] In addition, 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.

[0143] By configuring the liquid ejection head 1 to have the above-described structure, a voltage drop occurring near the center in the arrangement direction of the plurality of pressure chambers CV is suppressed in the common electrode Qb.

[0144] In addition, 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.

[0145] By making the cross-sectional area of the auxiliary wiring Aw larger, the common electrode Qb can be further made to have a lower resistance.

[0146] In addition, 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.

[0147] By providing the common electrode Qb and the individual electrode Qc on opposite surfaces of the piezoelectric body Qm, the piezoelectric element PZ can be deformed. Further, by vibrating the diaphragm 24 using the deformation of the piezoelectric element PZ, the pressure in the pressure chamber CV is changed, and then the ink filled inside the pressure chamber CV is ejected from the nozzle N.

[0148] In addition, 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 ejection operation of the liquid from the liquid ejection head 1.

[0149] By configuring the liquid ejection device 100 as described above, that is, by providing the auxiliary wiring Aw on the wiring substrate 4 instead of laminating the auxiliary electrode on the common electrode Qb, the common electrode Qb can be made to have a low resistance without increasing the thickness of the liquid ejection head 1.

[0150] 2: Second Embodiment

[0151] Hereinafter, while referring to Figure 9 the liquid ejection device 100 according to the second embodiment will be described. In addition, for the sake of simplicity of explanation, 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 below. In addition, for the structural elements included in the liquid ejection device 100 according to the second embodiment that are the same as those of the liquid ejection device 100 according to the first embodiment, the same reference numerals are used and the description of their functions may sometimes be omitted.

[0152] 2-1: Structure of Electrodes

[0153] The liquid ejection device 100 according to the second embodiment includes a liquid ejection head 1A instead of the liquid ejection head 1 included in the liquid ejection device 100 according to the first embodiment. Hereinafter, while referring to Figure 9 the structure of the individual electrode Qc and the common electrode Qb in the liquid ejection head 1A according to the second embodiment will be described.

[0154] Figure 9 FIG. is a top view of the liquid ejection head 1A when the liquid ejection head 1A is viewed from above in the Z1 direction.

[0155] The liquid ejection head 1A is different from the liquid ejection head 1. The liquid ejection head 1A is provided with a first individual electrode Qc1a instead of the first individual electrode Qc1 that is adjacent to the third connection electrode Qj3 in the Y-axis direction. Similarly, the liquid ejection head 1A is different from the liquid ejection head 1. The liquid ejection head 1A is provided with a second individual electrode Qc2a instead of the second individual electrode Qc2 that is adjacent to the third connection electrode Qj3 in the Y-axis direction.

[0156] The first individual electrode Qc1a is different from the first individual electrode Qc1. In the XY plane, the end on the X2 side of the first individual electrode Qc1a is located in the Y1 direction compared to the end on the X1 side. The first individual electrode Qc1a may have a bent shape in the XY plane as shown in Figure 9 or may have a linear shape inclined with respect to the Y axis.

[0157] The second individual electrode Qc2a is different from the second individual electrode Qc2. In the XY plane, the end on the X1 side of the second individual electrode Qc2a is located in the Y2 direction compared to the end on the X2 side. The second individual electrode Qc2a may have a bent shape in the XY plane as shown in Figure 9 or may have a linear shape inclined with respect to the Y axis.

[0158] 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. In addition, hereinafter, the connection points Jc1, Jc2, Jc1a, and Jc2a are collectively referred to as connection points Jcc.

[0159] In addition, hereinafter, the connection point between the third connection electrode Qj3 and the third common wiring Wb3 is referred to as connection point Jj3.

[0160] In the wiring substrate 4 included in the liquid ejection head 1A, the common electrode Qb and the individual electrode Qc are provided such that there is no connection point Jj3 between the adjacent connection points Jc1 and Jc2 among the plurality of connection points Jcc. In addition, in the wiring substrate 4 included in the liquid ejection head 1A, the common electrode Qb and the individual electrode Qc are provided such that there is a connection point Jj3 between the adjacent connection points Jc1a and Jc2a among the plurality of connection points Jcc.

[0161] In the wiring substrate 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 on the condition that there is no connection point Jj3 between the third connection electrode Qj3 and the third common wiring Wb3 in between. 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 in a state where there is no connection point Jj3 between the third connection electrode Qj3 and the third common wiring Wb3 in between.

[0162] The end portion on the X2 side of the first individual electrode Qc1 is located at the same position as the end portion on the X1 side in the Y-axis direction. On the other hand, as described above, in the XY plane, the first individual electrode Qc1a positions the end portion on the X2 side in the Y1 direction compared to the end portion on the X1 side.

[0163] In addition, the end portion on the X1 side of the second individual electrode Qc2 is located at the same position as the end portion on the X2 side in the Y-axis direction. On the other hand, as described above, in the XY plane, the second individual electrode Qc2a positions the end portion on the X1 side in the Y2 direction compared to the end portion on the X2 side.

[0164] Therefore, the interval between the connection point Jc1a and the connection point Jc2a is greater than the interval between the connection point Jc1 and the connection point Jc2.

[0165] In addition, 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".

[0166] 2-2: Effects achieved by the second embodiment

[0167] In the liquid ejection head 1A according to the present embodiment, between the connection point Jc1a and the connection point Jc2a 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, there is a connection point Jj3 between the third common wiring Wb3 and the third connection electrode Qj3. 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, there is no connection point Jj3 between the third common wiring Wb3 and the third connection electrode Qj3. The interval between the connection point Jc1a and the connection point Jc2a in the Y-axis direction is greater than the interval between the connection point Jc1 and the connection point Jc2 in the Y-axis direction.

[0168] By making the interval between connection point Jc1a and connection point Jc2a that sandwich connection point Jj3 greater than the interval between connection point Jc1 and connection point Jc2 that do not sandwich connection point Jj3, it is possible to suppress the noise induced by the third connection electrode Qj3 having connection point Jj3.

[0169] 3: Third Embodiment

[0170] Hereinafter, while referring to Figure 10 the liquid ejection device 100 according to the third embodiment will be described. In addition, 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. Further, for the structural elements included in the liquid ejection device 100 according to the third embodiment that are the same as those of the liquid ejection device 100 according to the first embodiment, the same reference numerals are used and the description of their functions may sometimes be omitted.

[0171] 3-1: Structure of Electrodes

[0172] The liquid ejection device 100 according to the third embodiment includes a liquid ejection head 1B instead of the liquid ejection head 1 included in the liquid ejection device 100 according to the first embodiment. Hereinafter, while referring to Figure 10 the structure of the individual electrodes Qc and the common electrode Qb in the liquid ejection head 1B according to the third embodiment will be described.

[0173] Figure 10 FIG. is a top view of the liquid ejection head 1B when the liquid ejection head 1B is viewed from above in the Z1 direction. In addition, for the sake of simplicity of explanation, in Figure 10 the structural elements included in the liquid ejection head 1B, the wiring substrate 4 and the elements located on the X1 side compared to the wiring substrate 4 are illustrated.

[0174] In the liquid ejection head 1B, the extending direction of the plurality of pressure chambers CV1 is inclined with respect to the Y-axis direction.

[0175] In Figure 10 the plurality of pressure chambers CV1 include pressure chamber CV1(1), pressure chamber CV1(2), pressure chamber CV1(3), and pressure chamber CV1(4). Hereinafter, in the liquid ejection head 1B illustrated in Figure 10 the pressure chambers CV1(1) to CV1(4) may be collectively referred to as a set of pressure chamber groups CV1s.

[0176] In addition, a 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 group of pressure chamber groups CV1s may sometimes be collectively referred to as a group of first individual electrode groups Qc1s.

[0177] 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).

[0178] 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. In addition, the extending direction of the first individual electrode Qc1(1) is inclined with respect to the Y-axis direction.

[0179] In addition, hereinafter, the direction from the wiring substrate 4 toward the piezoelectric body Qm(1) in the extending direction of the first individual electrode Qc1(1) is referred to as the GX1 direction, and the opposite direction of the GX1 direction is referred to as the GX2 direction. In addition, the GX1 direction and the GX2 direction are referred to as the GX direction.

[0180] In addition, hereinafter, the direction that coincides with the Z1 direction in the normal direction of the first individual electrode Qc1(1) is referred to as the GZ1 direction, and the direction that coincides with the Z2 direction is referred to as the GZ2 direction. In addition, the GZ1 direction and the GZ2 direction are referred to as the GZ direction.

[0181] In addition, hereinafter, the direction orthogonal to both the GX direction and the GZ direction is referred to as the GY direction. The direction in the GY direction that faces the X1 direction and the Y1 direction is referred to as the GY1 direction. The direction in the GY direction that faces the X2 direction and the Y2 direction is referred to as the GY2 direction.

[0182] The first individual electrode Qc1(2) is connected to the piezoelectric body Qm1(2). The first individual electrode Qc1(2) has a buckled 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).

[0183] The first electrode portion Qc1(2a) extends in the GX direction. In addition, 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. In addition, the end portion on the GX1 side of the first electrode portion Qc1(2a) is connected to the second electrode portion Qc1(2b).

[0184] The second electrode portion Qc1(2b) extends in the GY direction. In addition, the end portion on the GY2 side of the second electrode portion Qc1(2b) is connected to the first electrode portion Qc1(2a). In addition, the end portion on the GY1 side of the second electrode portion Qc1(2b) is connected to the third electrode portion Qc1(2c).

[0185] The third electrode portion Qc1(2c) extends in the GX direction. In addition, the end portion on the GX2 side of the third electrode portion Qc1(2c) is connected to the second electrode portion Qc1(2b). In addition, the end portion on the GX1 side of the third electrode portion Qc1(2c) is connected to the piezoelectric body Qm1(1).

[0186] A first individual electrode Qc1(3) is connected to the piezoelectric body Qm1(3). The first individual electrode Qc1(3) has a buckled 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).

[0187] The first electrode portion Qc1(3a) extends in the GX direction. In addition, 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. In addition, the end portion on the GX1 side of the first electrode portion Qc1(3a) is connected to the second electrode portion Qc1(3b).

[0188] The second electrode portion Qc1(3b) extends in the GY direction. In addition, the end portion on the GY2 side of the second electrode portion Qc1(3b) is connected to the first electrode portion Qc1(3a). In addition, the end portion on the GY1 side of the second electrode portion Qc1(3b) is connected to the third electrode portion Qc1(3c).

[0189] The third electrode portion Qc1(3c) extends in the GX direction. In addition, the end portion on the GX2 side of the third electrode portion Qc1(3c) is connected to the second electrode portion Qc1(3b). In addition, the end portion on the GX1 side of the third electrode portion Qc1(3c) is connected to the fourth electrode portion Qc1(3d).

[0190] The fourth electrode portion Qc1(3d) extends in the GY direction. In addition, the end portion on the GY2 side of the fourth electrode portion Qc1(3d) is connected to the third electrode portion Qc1(3c). In addition, the end portion on the GY1 side of the fourth electrode portion Qc1(3d) is connected to the fifth electrode portion Qc1(3e).

[0191] The fifth electrode portion Qc1(3e) extends in the GX direction. In addition, the end portion on the GX2 side of the fifth electrode portion Qc1(3e) is connected to the fourth electrode portion Qc1(3d). In addition, the end portion on the GX1 side of the fifth electrode portion Qc1(3e) is connected to the piezoelectric body Qm1(3).

[0192] A first individual electrode Qc1(4) is connected to the piezoelectric body Qm1(4). The first individual electrode Qc1(4) has a buckled shape 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).

[0193] The first electrode portion Qc1(4a) extends in the GX direction. In addition, the end portion on the GX2 side of the first electrode portion Qc1(4a) is connected to the individual wiring Wc within the wiring substrate 4. In addition, the end portion on the GX1 side of the first electrode portion Qc1(4a) is connected to the second electrode portion Qc1(4b).

[0194] The second electrode portion Qc1(4b) extends in the GY direction. In addition, the end portion on the GY2 side of the second electrode portion Qc1(4b) is connected to the first electrode portion Qc1(4a). In addition, the end portion on the GY1 side of the second electrode portion Qc1(4b) is connected to the third electrode portion Qc1(4c).

[0195] The third electrode portion Qc1(4c) extends in the GX direction. In addition, the end portion on the GX2 side of the third electrode portion Qc1(4c) is connected to the second electrode portion Qc1(4b). In addition, the end portion on the GX1 side of the third electrode portion Qc1(4c) is connected to the fourth electrode portion Qc1(4d).

[0196] The fourth electrode portion Qc1(4d) extends in the GY direction. In addition, the end portion on the GY2 side of the fourth electrode portion Qc1(4d) is connected to the third electrode portion Qc1(4c). In addition, the end portion on the GY1 side of the fourth electrode portion Qc1(4d) is connected to the fifth electrode portion Qc1(4e).

[0197] The fifth electrode portion Qc1(4e) extends in the GX direction. In addition, the end portion on the GX2 side of the fifth electrode portion Qc1(4e) is connected to the fourth electrode portion Qc1(4d). In addition, the end portion on the GX1 side of the fifth electrode portion Qc1(4e) is connected to the sixth electrode portion Qc1(4f).

[0198] The sixth electrode portion Qc1(4f) extends in the GY direction. In addition, the end portion on the GY2 side of the sixth electrode portion Qc1(4f) is connected to the fifth electrode portion Qc1(4e). In addition, the end portion on the GY1 side of the sixth electrode portion Qc1(4f) is connected to the seventh electrode portion Qc1(4g).

[0199] The seventh electrode portion Qc1(4g) extends in the GX direction. In addition, the end portion on the GX2 side of the seventh electrode portion Qc1(4g) is connected to the sixth electrode portion Qc1(4f). In addition, the end portion on the GX1 side of the seventh electrode portion Qc1(4g) is connected to the piezoelectric body Qm1(4).

[0200] A third connection electrode Qj3 is provided between the two first separate electrode groups Qc1s. The extending direction of the third connection electrode Qj3 is inclined with respect to the Y-axis direction.

[0201] In addition, in Figure 10 the illustrated example, the first separate electrodes Qc1(2) to Qc1(4) have a buckled shape in the XY plane, but may also be linear.

[0202] In addition, in Figure 10 as an example, a group of pressure chambers CV1s includes four pressure chambers CV1. However, the number of pressure chambers CV1 included in a group of pressure chambers CV1s may also be one to three, or may be five or more. Similarly, in Figure 10 as an example, a group of first separate electrode groups Qc1s includes four first separate electrodes Qc1. However, the number of first separate electrodes Qc1 included in a group of first separate electrode groups Qc1s may also be one to three, or may be five or more.

[0203] 4: Modification

[0204] The above-described embodiments can be variously modified. Specific modification methods are exemplified below. The methods exemplified below and the methods shown in the above-described embodiments can be appropriately combined within a range where they do not conflict with each other. In addition, in the modification examples exemplified below, for elements having the same functions as those in the embodiments, the reference signs used in the above description are used and their detailed descriptions are appropriately omitted.

[0205] 4-1: Modification 1

[0206] Figure 11 and Figure 12 It is an explanatory diagram for explaining various wirings provided on the wiring board 4A according to this modification example.

[0207] Figure 11 It is a structural diagram of the wiring board 4A for explaining the arrangement of the wirings and electronic components provided on the first surface FC1 when observing the first surface FC1 of the wiring board 4A from the FZ2 side toward the FZ1 side.

[0208] Figure 12 It is a structural diagram of the wiring board 4A for explaining the arrangement of the wirings provided on the second surface FC2 when observing the second surface FC2 of the wiring board 4A from the FZ1 side toward the FZ2 side. In Figure 12 For ease of explanation, a part of the wirings and electronic components provided on the first surface FC1 are illustrated by dashed lines.

[0209] In the first embodiment, when observing the wiring board 4 from above in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 are provided at overlapping positions. On the other hand, like Figure 11 and Figure 12 shown in this modification example, when observing the wiring board 4A from above in the FZ direction, the auxiliary wiring Aw and the integrated circuit 40 may also be provided at non-overlapping positions.

[0210] Since the auxiliary wiring Aw is not provided at the portion corresponding to the integrated circuit 40 in the second surface FC2, the generation of noise in the integrated circuit 40 is suppressed.

[0211] Symbol Explanation

[0212] 1, 1A, 1B... Liquid ejection heads; 4, 4A... Wiring substrates; 7... Control device; 21... Nozzle substrate; 22... Communication board; 23... Pressure chamber substrate; 24... Diaphragm; 25... Sealing substrate; 26... Flow path forming substrate; 40... Integrated circuit; 100... Liquid ejection device; 250, 260... Through holes; Aw... Auxiliary wiring; BL... Folding curve; CV, CV1, CV2... Pressure chambers; 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 points; 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 substrate part; Lb1... First common wiring extension part; Lb2... Second common wiring extension part; Lb3... Third common wiring extension part; Lc... Individual wiring extension part; N, N1, N2... Nozzles; PL1, PL2, PL3, PL4... Surfaces; PZ, PZ1, PZ2... Piezoelectric elements; 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 bodies; 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 liquid ejection head, characterized in that: have: a nozzle substrate on which a nozzle for spraying liquid is disposed; a pressure chamber substrate on which a plurality of pressure chambers for applying pressure to the liquid are disposed; 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; The wiring substrate includes individual wirings for applying voltage to the individual electrodes, common wirings for applying voltage to the common electrodes, and auxiliary wirings electrically connected to the common wirings for reducing the resistance of the common electrodes.

2. The liquid ejection head according to claim 1, wherein: The individual wiring and the common wiring are provided on the first surface of the wiring substrate. The auxiliary wiring is provided on a second surface behind the first surface of the wiring substrate.

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

4. The liquid ejection head according to claim 2, wherein: An integrated circuit connected to the individual wiring is also provided on the wiring substrate. The auxiliary wiring and the integrated circuit are provided at positions overlapping each other when the wiring substrate is viewed from above.

5. The liquid ejection head according to claim 2, wherein: An integrated circuit connected to the individual wiring is also provided on the wiring substrate. The auxiliary wiring and the integrated circuit are provided at positions not overlapping each other when the wiring substrate is viewed from above.

6. The liquid ejection head according to claim 1, wherein: 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.

7. The liquid ejection head according to claim 6, wherein: When the arrangement direction of the plurality of pressure chambers is set to a first direction, The first common wiring is connected to the common electrode at one side along the first direction relative to a connection position between the individual electrode and the individual wiring. The second common wiring is connected to the common electrode at the other side along the first direction relative to a connection position between the individual electrode and the individual wiring.

8. The liquid ejection head according to claim 6, wherein: The apparatus further comprises a third common wiring line, wherein when the arrangement direction of the plurality of pressure chambers is set to the first direction, The third common wiring is provided between the first common wiring and the second common wiring in the first direction, and electrically connects the common electrode and the auxiliary wiring.

9. The liquid ejection head according to claim 8, wherein: 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.

10. The liquid ejection head according to claim 1, wherein The cross-sectional area of ​​the auxiliary wiring is larger than the cross-sectional area of ​​the independent wiring.

11. The liquid ejection head according to claim 1, wherein The common electrode is provided on a surface of the piezoelectric body that is opposite to the surface on the pressure chamber side. The individual electrode is provided on a surface of the piezoelectric body on the pressure chamber side.

12. The liquid ejection head according to claim 1, wherein When the arrangement direction of the plurality of pressure chambers is set to a first direction, and a connection point between the common wiring and the common electrode exists between a first connection point and a second connection point adjacent to each other in the first direction among the connection points between the individual wiring and the individual electrode, When there is no connection point between the common wiring and the common electrode between a third connection point and a fourth connection point adjacent to each other in the first direction among the connection points between the individual wiring and the individual electrode, A distance between the first connection point and the second connection point in the first direction is greater than a distance between the third connection point and the fourth connection point in the first direction.

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

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