Liquid jet head

Abstract

To provide a liquid jet head that can exert high injection performance.SOLUTION: A liquid jet head includes: a flow passage formation substrate which has a pressure chamber partitioned by a bulkhead; a diaphragm which is provided on one surface side of the flow passage formation substrate; a piezoelectric actuator which is provided along a first direction from the one surface side of the diaphragm and has a first electrode, a piezoelectric layer and a second electrode; a curvature control unit which can control a curvature of the diaphragm, overlaps with the diaphragm when viewed from the first direction, and is provided along an edge of the pressure chamber.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a liquid jet head. [Background technology]

[0002] Image forming apparatuses equipped with liquid ejection heads that eject liquid such as ink onto a medium such as printing paper have been proposed. In recent years, image forming apparatuses have been attracting attention not only for printing purposes but also as devices that can apply liquefied materials to any location. As a liquid ejection head included in an image forming apparatus, a head that ejects liquid filled in a pressure chamber from a nozzle by vibrating a vibration plate that constitutes a part of the pressure chamber using a piezoelectric element is known.

[0003] The liquid jet head described in Patent Document 1 includes a flow path forming substrate having pressure chambers partitioned by partition walls, a vibration plate provided on the flow path forming substrate, and a piezoelectric element provided on the vibration plate. The piezoelectric element includes a first electrode, a second electrode, and an active part sandwiched between them. The active part is provided with a weight that straddles the boundary between the pressure chamber and the partition wall that partitions the pressure chamber. The weight improves the strength of the partition wall and suppresses cracks in the vibration plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-157069 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the thickness of the diaphragm is designed so that the compliance of the diaphragm is a desired value. The curvature of the diaphragm is automatically determined by the design of the thickness. For this reason, it has been difficult to design the compliance and curvature of the diaphragm independently. Therefore, it has been difficult to achieve high ejection performance according to the application. In addition, the curvature of the diaphragm affects the displacement and responsiveness of the diaphragm. For this reason, it has been desired to control the curvature of the diaphragm more uniformly. [Means for solving the problem]

[0006] A liquid jet head according to a preferred embodiment of the present invention comprises a flow path forming substrate having pressure chambers separated by partitions, a vibration plate provided on one side of the flow path forming substrate, a piezoelectric actuator having a first electrode, a piezoelectric layer and a second electrode provided along a first direction from one side of the vibration plate, and a curvature control unit capable of controlling the curvature of the vibration plate, the curvature control unit overlapping with the vibration plate when viewed from the first direction and provided along an edge of the pressure chamber. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to a first embodiment. [Diagram 2] 2 is an exploded perspective view of the liquid jet head shown in FIG. [Diagram 3] 2 is a cross-sectional view of a portion of the liquid jet head shown in FIG. [Figure 4] 4 is an enlarged view of a portion of the liquid jet head of FIG. 3. [Diagram 5] 4 is an enlarged view of a portion of the liquid jet head of FIG. 3. [Figure 6] 4 is an enlarged plan view of a portion of the liquid jet head of FIG. 3. [Figure 7] 11 is a cross-sectional view for explaining the operation of a curvature control unit. FIG. [Figure 8] 11 is a cross-sectional view for explaining the operation of a curvature control unit. FIG. [Figure 9]11 is an enlarged cross-sectional view of a portion of a liquid jet head according to a first modified example. FIG. [Figure 10] 11 is an enlarged cross-sectional view of a portion of a liquid jet head according to a second modified example. FIG. [Figure 11] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a third modified example. FIG. [Figure 12] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a fourth modified example. FIG. [Figure 13] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a fifth modified example. FIG. [Figure 14] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a sixth modified example. FIG. [Figure 15] 13 is an enlarged plan view of a portion of a liquid jet head according to a seventh modified example. FIG. [Figure 16] 13 is an enlarged plan view of a portion of a liquid jet head according to an eighth modified example. FIG. [Figure 17] 11 is an enlarged cross-sectional view of a portion of a liquid jet head according to a second embodiment. FIG. [Figure 18] 11 is an enlarged plan view of a portion of a liquid jet head according to a second embodiment. FIG. [Figure 19] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a ninth modified example. FIG. [Figure 20] 13 is an enlarged cross-sectional view of a portion of a liquid jet head according to a tenth modified example. FIG. [Figure 21] 16 is an enlarged cross-sectional view of a portion of a liquid jet head according to an eleventh modified example. FIG. [Figure 22] 23 is an enlarged cross-sectional view of a portion of a liquid jet head according to a twelfth modified example. FIG. [Diagram 23] 23 is an enlarged cross-sectional view of a portion of a liquid jet head according to a thirteenth modified example. FIG. [Figure 24] 23 is an enlarged cross-sectional view of a portion of a liquid jet head according to a fourteenth modified example. FIG. [Diagram 25] 23 is an enlarged cross-sectional view of a portion of a liquid jet head according to a fifteenth modified example. FIG. [Figure 26] 11 is an enlarged cross-sectional view of a portion of a liquid jet head according to a first modified example. FIG. [Figure 27]23 is an enlarged plan view of a portion of a liquid jet head according to a seventeenth modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. The scope of the present invention is not limited to these forms unless otherwise specified in the following description to the effect that the present invention is limited thereto. In addition, "element β on element γ" is not limited to a configuration in which element γ and element β are in direct contact with each other, but also includes a configuration in which element γ and element β are not in direct contact with each other.

[0009] 1. First embodiment 1-1. Overall configuration of image forming apparatus 100 FIG. 1 is a schematic diagram illustrating the configuration of an image forming apparatus 100 according to a first embodiment. In the following, for convenience of explanation, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other will be appropriately used. Moreover, one direction along the X-axis will be referred to as the X1 direction, and the direction opposite to the X1 direction will be referred to as the X2 direction. Similarly, one direction along the Y-axis will be referred to as the Y1 direction, and the direction opposite to the Y1 direction will be referred to as the Y2 direction. One direction along the Z-axis will be referred to as the Z1 direction, and the direction opposite to the Z1 direction will be referred to as the Z2 direction.

[0010] The image forming apparatus 100 in FIG. 1 is an inkjet printing apparatus that ejects ink, which is an example of a liquid, onto a medium 90. The medium 90 is typically printing paper, but a printing target made of any material, such as a resin film or fabric, can be used as the medium 90. As illustrated in FIG. 1, the image forming apparatus 100 is provided with a liquid container 9 that stores ink. For example, a cartridge that can be detached from the image forming apparatus 100, a bag-shaped ink pack made of a flexible film, or an ink tank that can be refilled with ink can be used as the liquid container 9.

[0011] The image forming apparatus 100 includes a control unit 20, a medium conveying mechanism 22, a moving mechanism 24, and a liquid ejecting head 3. The control unit 20 includes one or more processing circuits, such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits, such as a semiconductor memory, and performs overall control of each element of the image forming apparatus 100.

[0012] The medium transport mechanism 22 transports the medium 90 in a direction along the Y axis under the control of the control unit 20. In addition, the movement mechanism 24 reciprocates the liquid jet head 3 along the X axis under the control of the control unit 20. The movement mechanism 24 includes a substantially box-shaped transport body 242 that houses the liquid jet head 3, and a transport belt 244 to which the transport body 242 is fixed. Note that a configuration in which a plurality of liquid jet heads 3 are mounted on the transport body 242, or a configuration in which the liquid container 9 is mounted on the transport body 242 together with the liquid jet head 3, may also be employed.

[0013] The liquid ejection heads 3 eject ink supplied from a liquid container 9 from multiple nozzles onto the medium 90 under the control of the control unit 20. An image is formed on the surface of the medium 90 by each liquid ejection head 3 ejecting ink onto the medium 90 in parallel with the transport of the medium 90 by the medium transport mechanism 22 and the repeated reciprocating motion of the transport body 242.

[0014] The image forming apparatus 100 has a liquid jet head 3 having the characteristics described below, and is therefore capable of exhibiting high jetting performance.

[0015] 1-2. Overall configuration of liquid ejection head 3 Fig. 2 is an exploded perspective view of the liquid jet head 3 shown in Fig. 1. Fig. 3 is a cross-sectional view of a portion of the liquid jet head 3 shown in Fig. 1, taken along line aa in Fig. 2. The cross section shown in Fig. 3 is a cross section parallel to the XZ plane. The Z axis is an axis line along the direction in which ink is ejected by the liquid jet head 3. The Z2 direction corresponds to the "first direction".

[0016] 2, the liquid jet head 3 includes a plurality of nozzles N arranged along the Y axis. The plurality of nozzles N in the first embodiment are divided into a first row La and a second row Lb arranged side by side at intervals along the X axis. Each of the first row La and the second row Lb is a collection of a plurality of nozzles N arranged linearly along the Y axis. The liquid jet head 3 has a structure in which elements related to each nozzle N in the first row La and elements related to each nozzle N in the second row Lb are arranged in a substantially plane-symmetrical manner. In the following description, the elements corresponding to the second row Lb will be mainly described, and descriptions of the elements corresponding to the first row La will be omitted as appropriate.

[0017] 2 and 3, the liquid jet head 3 includes a substrate 31, a flow path forming substrate 32, a vibration plate 33, a nozzle plate 37, a vibration absorber 39, a plurality of piezoelectric actuators 34, a sealing body 35, a housing unit 36, and a wiring substrate 40. Each of the substrate 31, the flow path forming substrate 32, the vibration plate 33, the nozzle plate 37, the vibration absorber 39, the sealing body 35, and the housing unit 36 ​​is a long plate-like member along the Y axis. Moreover, the nozzle plate 37, the substrate 31, the flow path forming substrate 32, the vibration plate 33, and the sealing body 35 are arranged in this order in the Z2 direction. Moreover, the liquid jet head 3 has a curvature control unit 5 shown in FIG. 4 described later.

[0018] The nozzle plate 37 is a plate-like member in which a plurality of nozzles N are formed. Each of the plurality of nozzles N is a circular through-hole for ejecting ink. The nozzle plate 37 is bonded to the surface of the substrate 31 in the Z1 direction by, for example, an adhesive.

[0019] The substrate 31 forms a flow path through which the ink flows. Specifically, the substrate 31 is formed with a space Ra, an intermediate liquid chamber Rb, a plurality of supply flow paths 312, and a plurality of communication flow paths 314. The space Ra is an opening formed in an elongated shape along the Y axis. Each of the supply flow paths 312 and the communication flow paths 314 is a through hole formed for each nozzle N. Each communication flow path 314 overlaps with a corresponding nozzle N in a plan view seen from the Z1 direction. The intermediate liquid chamber Rb is a space formed in an elongated shape along the Y axis across the plurality of nozzles N, and connects the space Ra and the plurality of supply flow paths 312 to each other. A flow path forming substrate 32 is bonded to the Z2 direction surface of the substrate 31 with an adhesive.

[0020] A plurality of pressure chambers C1 are formed in the flow path forming substrate 32. Ink to be ejected from the nozzle N is stored in the pressure chambers C1. The pressure chambers C1 are located between the nozzle plate 37 and the vibration plate 33, and are spaces partitioned by partition walls of the flow path forming substrate 32. The pressure chambers C1 are formed for each nozzle N. The pressure chambers C1 are elongated spaces and extend in the X1 direction. The plurality of pressure chambers C1 are aligned along the Y axis. Each pressure chamber C1 communicates with the communication flow path 314 and the supply flow path 312. Therefore, the pressure chambers C1 communicate with the nozzle N via the communication flow path 314, and communicate with the space Ra via the supply flow path 312 and the relay liquid chamber Rb.

[0021] The nozzle plate 37, the substrate 31, and the flow path forming substrate 32 are manufactured by processing a single crystal substrate of silicon (Si) using semiconductor manufacturing techniques such as photolithography, etching, etc. However, the nozzle plate 37, the substrate 31, and the flow path forming substrate 32 may be manufactured using any known material or method.

[0022] The vibration plate 33 is provided on a surface 32a facing the Z2 direction, which is one side of the flow path forming substrate 32. The surface 32a is the surface of the flow path forming substrate 32 opposite to the surface to which the substrate 31 is bonded. The vibration plate 33 is disposed on the pressure chamber C1 and is elastically deformable. The vibration plate 33 is a plate-like member formed in an elongated rectangular shape along the Y axis in a plan view. The vibration plate 33 and the flow path forming substrate 32 may be integrally configured, or may be configured as separate bodies and bonded with an adhesive or the like.

[0023] A piezoelectric actuator 34 is formed on the surface of the vibration plate 33 opposite to the pressure chamber C1. A piezoelectric actuator 34 is provided for each pressure chamber C1. The piezoelectric actuator 34 has an elongated shape along the X-axis in a plan view. The piezoelectric actuator 34 is a piezoelectric element that applies pressure to the ink in the pressure chamber C1. The piezoelectric actuator 34 is driven by application of a drive signal including a drive waveform.

[0024] The sealing body 35 is bonded to the vibration plate 33 by, for example, an adhesive. The sealing body 35 is a structure that protects the multiple piezoelectric actuators 34 and reinforces the mechanical strength of the flow path forming substrate 32 and the vibration plate 33. A recess is formed in the sealing body 35 on the surface facing the vibration plate 33. The multiple piezoelectric actuators 34 are housed inside the recess. The sealing body 35 also has a space 353 through which the wiring board 40 is inserted.

[0025] The housing 36 is bonded to the substrate 31 by, for example, an adhesive. The housing 36 is a case for storing ink to be supplied to the multiple pressure chambers C1. The housing 36 is formed by, for example, injection molding of a resin material. A space Rc, a supply port 361, and a space 362 are formed in the housing 36. The supply port 361 is a conduit through which ink is supplied from the liquid container 9, and communicates with the space Rc. The space Rc communicates with the space Ra of the substrate 31. The space formed by the space Rc and the space Ra functions as a liquid storage chamber R that stores ink to be supplied to the multiple pressure chambers C1. The ink supplied from the liquid container 9 and passing through the supply port 361 is stored in the liquid storage chamber R. The ink stored in the liquid storage chamber R branches from the relay liquid chamber Rb to each supply flow path 312 and is supplied in parallel to the multiple pressure chambers C1. The space 362 overlaps with the space 353 of the sealing body 35 in a plan view. The wiring board 40 is inserted through the space 353 and the space 362 .

[0026] The wiring board 40 is connected to the vibration plate 33. The wiring board 40 is a mounting component on which a plurality of wirings are formed for electrically connecting the control unit 20 and the liquid ejecting head 3. For example, a flexible wiring board 40 such as an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable) is preferably used. A drive signal and a reference voltage for driving the piezoelectric actuators 34 are supplied to each piezoelectric actuator 34 from the wiring board 40.

[0027] Further, a vibration absorber 39 is bonded, for example, by an adhesive to the surface in the Z1 direction of the substrate 31. The vibration absorber 39 is a flexible film that constitutes the wall surface of the space Ra, and absorbs pressure fluctuations of the ink in the liquid storage chamber R.

[0028] 1-3. Specific Configuration of Part of Liquid Jet Head 3 Fig. 4 and Fig. 5 are enlarged views of a portion of the liquid jet head 3 of Fig. 3. The cross section shown in Fig. 4 is a cross section parallel to the YZ plane. The cross section shown in Fig. 5 is a cross section parallel to the XZ plane. Fig. 6 is an enlarged plan view of a portion of the liquid jet head 3 of Fig. 3.

[0029] 4 and 5, the piezoelectric actuator 34 generally includes a first electrode 341, a piezoelectric layer 343, and a second electrode 342. The first electrode 341, the piezoelectric layer 343, and the second electrode 342 are provided along the Z2 direction, which is the "first direction", from a surface 33a facing the Z2 direction, which is one side of the vibration plate 33.

[0030] The first electrode 341 is provided on the surface 33a of the vibration plate 33. In this embodiment, the first electrodes 341 are individual electrodes formed at a distance from each other for each piezoelectric actuator 34. A drive signal with a fluctuating voltage is applied to the first electrode 341. The first electrode 341 is elongated along the X-axis. The multiple first electrodes 341 are arranged along the Y-axis at intervals from each other. The first electrodes 341 are formed of a conductive material such as platinum (Pt) or iridium (Ir).

[0031] The piezoelectric layer 343 is sandwiched between the first electrode 341 and the second electrode 342. The piezoelectric layer 343 is, for example, a strip-shaped dielectric film that is continuous along the Y axis across the multiple piezoelectric actuators 34. The piezoelectric layer 343 is, for example, strip-shaped extending along the Y axis. As shown in FIG. 6, the piezoelectric layer 343 has multiple notches G. The multiple notches G cause the piezoelectric layer 343 to have active sections 3430 separated for each piezoelectric actuator 34. The active sections 3430 overlap with the pressure chambers C1 of the piezoelectric layer 343 when viewed in the Z2 direction.

[0032] The piezoelectric layer 343 is formed of a piezoelectric material containing, for example, one or more of Pb, Ti, Zr, K, Na, Nb, Ba, Fe, Bi, Ta, Cr, IR, Hf, Li, C, and La. Examples of the piezoelectric material include lead zirconate titanate (PZT: Pb(Zr,Ti)O3), potassium sodium niobate (KNN: (K,Na)NbO3), and barium titanate (BaRiO3). Among them, lead zirconate titanate (PZT) is preferably used as the material for the piezoelectric body 443. The piezoelectric layer 343 may contain small amounts of other elements such as impurities.

[0033] The second electrode 342 is provided on the piezoelectric layer 343. The second electrode 342 is a band-shaped common electrode extending along the Y axis so as to be continuous across the multiple piezoelectric actuators 34. A predetermined reference voltage is applied to the second electrode 342. The second electrode 342 is formed of a low-resistance conductive material such as platinum or iridium. For example, the piezoelectric actuator 34 on the left side in FIG. 4 and the piezoelectric actuator 34 on the right side in FIG. 4 are defined as the "second piezoelectric actuator". In this case, the piezoelectric actuator 34 on the left side in FIG. 4 and the piezoelectric actuator 34 on the right side in FIG. 4 have a common second electrode 342.

[0034] A voltage corresponding to the difference between a reference voltage applied to the second electrode 342 and a drive signal corresponding to the ejection amount supplied to the first electrode 341 is applied to the piezoelectric layer 343. When a voltage is applied between the first electrode 341 and the second electrode 342, an active part 3430 of the piezoelectric layer 343 is deformed. This deformation causes the piezoelectric actuator 34 to flexibly deform the vibration plate 33, i.e., to vibrate. When the vibration plate 33 vibrates, the pressure in the pressure chamber C1 changes, and the ink in the pressure chamber C1 is ejected from the nozzle N.

[0035] 5, wiring 38 electrically connected to second electrode 342 is provided on the surface of second electrode 342. A reference voltage is supplied to wiring 38 from control unit 20 shown in FIG. 1 via wiring board 40 shown in FIG.

[0036] 5 and 6, the wiring 38 has a strip-shaped first conductive layer 381 extending along the Y-axis and a strip-shaped second conductive layer 382 extending along the Y-axis. The first conductive layer 381 and the second conductive layer 382 are arranged at a predetermined interval along the X-axis. By providing the first conductive layer 381 and the second conductive layer 382, ​​a voltage drop of the reference voltage in the second electrode 342 is suppressed. The first conductive layer 381 and the second conductive layer 382 also function as a weight for suppressing the vibration of the diaphragm 33.

[0037] The material of the wiring 38 is, for example, a conductive material such as gold (Au). The wiring 38 is preferably formed of a conductive material having a lower resistance than the second electrode 342. The wiring 38 may be a single layer or multiple layers.

[0038] The diaphragm 33 is provided on a surface 32a facing the Z2 direction of the flow path forming substrate 32. The diaphragm 33 vibrates when driven by a piezoelectric actuator . In the example shown in the figure, the diaphragm 33 is formed of a laminate including a first layer 331 and a second layer 332.

[0039] The first layer 331 contacts the flow path forming substrate 32. The first layer 331 contains, for example, Ti, Si, Al, Ta, Cr, Ir, Hf, Zr, or C. The first layer 331 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials. Specifically, for example, the first layer 331 is preferably an oxide such as silicon dioxide (SiO2), or diamond-like carbon (DLC).

[0040] The second layer 332 functions as a diffusion prevention layer. The second layer 332 contains, for example, Ti, Si, Al, Ta, Cr, Ir, Hf, Zr, Cr, or Pb. The adhesion layer 333 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials. Specifically, for example, the material of the second layer 332 is preferably zirconium oxide (ZrOx), lead titanate (PbTiOx), titanium oxide (TiOx), or ((Pb,Bi)(Fe,Ti)Ox).

[0041] Each layer of the diaphragm 33 is formed by a known film formation technique such as sputtering, etc. The diaphragm 33 may be composed of one layer, or three or more layers.

[0042] 1-4. Curvature control section 5 4 and 5, a curvature control section 5 is provided on the second electrode 342 or the wiring 38 of the piezoelectric actuator 34. The curvature control section 5 is provided to control the curvature of the diaphragm 33. The curvature control section 5 is a film that has residual stress in a predetermined direction due to a thermal process in its manufacture.

[0043] In the example shown in FIG. 6, the curvature control section 5 includes a first portion 51, a second portion 52, and a plurality of third portions 53. The first portion 51 and the second portion 52 are spaced apart from each other and extend along the Y1 direction. The first portion 51 is disposed on a first conductive layer 381. The second portion 52 is disposed on a second conductive layer 382. The plurality of third portions 53 are located between the first portion 51 and the second portion 52 and connect them. Each of the plurality of third portions 53 extends in the X2 direction. The plurality of third portions 53 are spaced apart from each other and aligned in the Y1 direction.

[0044] The curvature control unit 5 overlaps with the vibration plate 33 when viewed from the Z2 direction. The curvature control unit 5 is provided along the edge 320, which is the outer edge of the pressure chamber C1 when viewed in the Z2 direction. In this embodiment, the pressure chamber C1 is rectangular when viewed in the Z2 direction. Therefore, the curvature control unit 5 is provided along the four sides of the pressure chamber C1 when viewed in the Z2 direction.

[0045] Conventionally, when the curvature of the diaphragm 33 was changed, the configuration of the diaphragm 33 had to be changed. Therefore, when the curvature of the diaphragm 33 was changed, the compliance of the diaphragm 33 was also changed at the same time. Therefore, when the diaphragm 33 was designed by prioritizing the compliance of the diaphragm 33, it was difficult to design the diaphragm 33 having an optimal curvature according to the application of the liquid ejection head 3.

[0046] In contrast, the liquid jet head 3 of the present embodiment has a curvature control unit 5. Therefore, the curvature of the diaphragm 33 can be designed by the curvature control unit 5 separately from the compliance of the diaphragm 33. For example, the compliance of the diaphragm 33 can be set to a desired value by the configuration of the diaphragm 33, such as the thickness, and the curvature of the diaphragm 33 can be adjusted by the curvature control unit 5. Therefore, the liquid jet head 3 can exhibit higher jetting performance than conventional ones.

[0047] The curvature of the diaphragm 33 affects the displacement and responsiveness of the diaphragm 33. The more the diaphragm 33 deforms, the harder it becomes. The harder it is, the faster it responds. For example, the smaller the curvature of the diaphragm 33, i.e., the larger the radius of curvature of the diaphragm 33, the greater the displacement that can be achieved while the diaphragm 33 is soft. For this reason, the smaller the curvature of the diaphragm 33, the greater the displacement of the diaphragm 33. Thus, the ejection amount increases. However, the smaller the curvature of the diaphragm 33, the greater the displacement of the diaphragm 33, but the slower the response speed. On the other hand, the larger the curvature of the diaphragm 33, i.e., the smaller the radius of curvature of the diaphragm 33, the greater the deformation of the diaphragm 33 must be, so the displacement of the diaphragm 33 decreases. However, the response speed of the diaphragm 33 becomes faster. A diaphragm 33 with a fast response speed is optimal for high-frequency driving.

[0048] As described above, the greater the curvature of the diaphragm 33, the faster the response speed of the diaphragm 33. On the other hand, the smaller the curvature of the diaphragm 33, the slower the response speed. This difference in response is on the order of sub-microseconds. However, this difference causes a phase shift of the residual vibration. In particular, in high-frequency driving, which is easily affected by residual vibration, the ejection timing may deviate from the optimal ejection timing of the drive waveform due to the phase shift. This may result in an increase or decrease in the weight of the ejected ink, or a deterioration in ejection stability.

[0049] Fig. 7 is a cross-sectional view for explaining the operation of the curvature control section 5. Fig. 8 is a plan view for explaining the operation of the curvature control section 5.

[0050] For example, consider a case where the curvature is to be increased. In this case, as shown in FIG. 7, a curvature control unit 5 is used in which the direction of the residual stress is a direction that spreads in the XY plane as shown by the two-way arrow A1. When such a curvature control unit 5 is used, the vibration plate 33 extends in the direction shown by the arrow A2 as shown in FIG. 7 and FIG. 8. Specifically, the portion of the vibration plate 33 corresponding to the pressure chamber C1 extends in a direction toward the center of the portion as viewed from the Z2 direction. As a result, the vibration plate 33 deforms in the Z1 direction as shown by the arrow A3 in FIG. 7. Therefore, the curvature of the vibration plate 33 increases. Therefore, the response speed of the vibration plate 33 can be increased.

[0051] In this example, when the diaphragm 33 is hard due to a small compliance value of the membrane of the diaphragm 33 itself, a hard diaphragm 33 with a fast response speed for high frequency driving can be obtained. Therefore, a response speed faster than the response speed according to the curvature that was conventionally determined only by the configuration of the membrane of the diaphragm 33 itself can be exhibited. Therefore, in high frequency driving, ejection at the optimal ejection timing is possible, and high ejection performance can be exhibited.

[0052] In this way, by providing the curvature control section 5, it is possible to control only the curvature without impairing the compliance of the vibration plate 33. Furthermore, the curvature control section 5 is provided along the edge 320 of the pressure chamber C1. Therefore, it is possible to uniformize the force that controls the curvature of the portion of the vibration plate 33 that corresponds to the pressure chamber C1.

[0053] Moreover, when viewed from the Z2 direction, the curvature control section 5 does not overlap with the active section 3430 of the piezoelectric layer 343. That is, the curvature control section 5 is provided at a position different from the active section 3430 when viewed from the Z2 direction.

[0054] The active part 3430 is a part that varies when the piezoelectric actuator 34 is driven. Therefore, the part of the diaphragm 33 that overlaps with the active part 3430 when viewed in the Z2 direction is a part that varies. By providing the curvature control part 5 at a part of the piezoelectric actuator 34 that does not vary other than the active part 3430, the curvature of the diaphragm 33 can be controlled at the part that does not vary. Therefore, the influence on the part that varies can be suppressed. Therefore, only the curvature can be suitably controlled without impairing the compliance of the diaphragm 33.

[0055] Furthermore, the curvature control portion 5 does not overlap with the pressure chamber C1 when viewed from the Z2 direction. That is, the curvature control portion 5 is provided at a position different from the pressure chamber C1 when viewed from the Z2 direction.

[0056] The pressure chamber C1 is a portion that allows fluctuations in a fluctuating portion of the diaphragm 33. For this reason, the curvature control portion 5 does not overlap with the pressure chamber C1 when viewed in the Z2 direction, and therefore it is possible to control only the curvature without impeding the compliance of the diaphragm 33.

[0057] Furthermore, the curvature control unit 5 is provided on the upper surface of the second electrode 342 in the Z2 direction. This upper surface faces the Z2 direction. Since the curvature control unit 5 is provided on the upper surface of the second electrode 342, the curvature control unit 5 is manufactured in a process later than the second electrode 342. For this reason, the curvature control unit 5 can be added without affecting the existing structure and process of the piezoelectric actuator 34. Therefore, the curvature control unit 5 can be easily added to piezoelectric actuators having configurations other than the piezoelectric actuator 34 of the configuration of this embodiment.

[0058] In addition, in this embodiment, no other members are arranged on the upper surface of the curvature control portion 5. The upper surface is a surface facing the Z2 direction. Therefore, it is easy to adjust the thickness of the curvature control portion 5 as desired. Therefore, by forming the curvature control portion 5 of a desired thickness, it is easy to control the curvature of the diaphragm 33 to a desired curvature. Furthermore, since no other members are arranged on the upper surface of the curvature control portion 5, it is possible to avoid application of heat to the curvature control portion 5 in the thermal process for forming the other members. Therefore, it is possible to avoid the residual stress of the curvature control portion 5 from changing due to the formation of the other members. Therefore, after forming the curvature control portion 5 having the desired residual stress, it is possible to avoid the residual stress from changing. Therefore, it is more certain that the curvature control portion 5 is designed to be a film having the desired residual stress. Therefore, it is easier to form the diaphragm 33 having the desired curvature.

[0059] The material of the curvature control part 5 is not particularly limited, and may be a metal or a nonmetal. Examples of such materials include Ti, Si, Al, Ta, Cr, Ir, Hf, Ar, C, Pb, and Au. The curvature control part 5 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials. Among these, the material of the curvature control part 5 is preferably TiOx, AlOx, CrOx, or Au. These materials have excellent adhesion to the piezoelectric actuator 34 and are easy to adjust the residual stress. It is particularly preferable that the curvature control part 5 contains Au. By containing Au, it is easiest to adjust the residual stress to the desired level.

[0060] The curvature control part 5 may be a single layer or multiple layers. The residual stress of the curvature control part 5 is designed by, for example, the material, the area, the height, the heat treatment temperature, the heat treatment time, etc. Therefore, the area and the height of the curvature control part 5 are not particularly limited.

[0061] 2. Modification of the First Embodiment The first embodiment may be modified in various ways. For example, specific modified aspects that may be applied to the first embodiment are illustrated below. Two or more aspects arbitrarily selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0062] 2-1. First modified example 9 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the first modified example. The curvature control unit 5A of the first modified example shown in FIG. 9 overlaps with the pressure chamber C1 when viewed from the Z2 direction. The curvature control unit 5A is provided so as to straddle the edge 320 of the pressure chamber C1. Therefore, the plane area of ​​the curvature control unit 5A is larger than the plane area of ​​the curvature control unit 5 of the first embodiment described above. Therefore, the curvature control unit 5A is provided over a wider area than the curvature control unit 5 of the first embodiment described above. Therefore, the curvature control unit 5A can more strongly control the curvature of the vibration plate 33.

[0063] Furthermore, the curvature control unit 5A overlaps with the active portion 3430 of the piezoelectric layer 343 when viewed from the Z2 direction. Therefore, the curvature control unit 5A is provided over a much wider range than in the first embodiment. Therefore, the curvature of the diaphragm 33 can be more strongly controlled by the curvature control unit 5A.

[0064] 2-2. Second modified example 10 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the second modified example. The curvature control unit 5B of the second modified example shown in FIG. 10 overlaps a portion of the pressure chamber C1 when viewed from the Z2 direction. The curvature control unit 5B is provided so as to straddle the edge 320 of the pressure chamber C1. Therefore, the plane area of ​​the curvature control unit 5B is larger than the plane area of ​​the curvature control unit 5 of the first embodiment described above. Therefore, the curvature control unit 5B is provided over a wider area than the curvature control unit 5 of the first embodiment described above. Therefore, the curvature control unit 5B can more strongly control the curvature of the vibration plate 33.

[0065] However, when viewed from the Z2 direction, the curvature control section 5B does not overlap with the active section 3430 of the piezoelectric layer 343. Therefore, according to the second modification, it is easier to control the curvature of the diaphragm 33 while suppressing the effect of providing the curvature control section 5B on the fluctuation of the diaphragm 33.

[0066] 2-3.Third modified example Fig. 11 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the third modified example. The curvature control unit 5C of the third modified example shown in Fig. 11 is provided inside the vibration plate 33 in the Z2 direction. In the example shown in the figure, the curvature control unit 5C is provided between the first layer 331 and the second layer 332. Therefore, compared to the first embodiment described above, it is possible to suppress interference of the curvature control unit 5C with the structure of the piezoelectric actuator 34. In addition, since the curvature control unit 5C can be provided on a flat layer of the vibration plate 33, the curvature control unit 5C can be easily manufactured.

[0067] 2-4.Fourth modified example Fig. 12 is an enlarged cross-sectional view of a portion of a liquid jet head 3 according to a fourth modified example. The vibration plate 33A according to the fourth modified example shown in Fig. 12 further includes an adhesion layer 333. The vibration plate 33A is configured of a laminate including a first layer 331, the adhesion layer 333, and a second layer 332. The adhesion layer 333 is disposed between the first layer 331 and the second layer 332, and enhances adhesion therebetween.

[0068] The material of the adhesion layer 333 includes, for example, Ti, Si, Al, Ta, Cr, Ir, Hf, Zr, or C. The adhesion layer 333 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials. In particular, the material of the adhesion layer 333 is preferably TiOx, AlOx, CrOx, or TiN from the viewpoint of adhesion.

[0069] 2-5. Fifth Modification Fig. 13 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the fifth modified example. The vibration plate 33B of the fifth modified example shown in Fig. 13 further includes a first functional layer 334, an adhesion layer 333, and a second functional layer 335. The vibration plate 33B is configured of a laminate including a first layer 331, a first functional layer 334, an adhesion layer 333, a second functional layer 335, and a second layer 332. The first layer 331, the first functional layer 334, the adhesion layer 333, the second functional layer 335, and the second layer 332 are arranged in this order in the Z2 direction. The adhesion layer 333 is as described in the fourth modified example.

[0070] The first functional layer 334 has a function of controlling the stress on the first layer 331 side of the diaphragm 33B. The second functional layer 335 has a function of controlling the stress on the second layer 332 side of the diaphragm 33B. The first functional layer 334 includes, for example, Ti, Si, Al, Ta, Cr, Ir, Hf, Zr, or C. The first functional layer 334 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials. The second functional layer 335 includes, for example, Ti, Si, Al, Ta, Cr, Ir, Hf, Zr, Cr, or Pb. The second functional layer 335 is composed of, for example, a simple substance of such a material, or a compound such as an oxide or nitride containing one or more of such materials.

[0071] 2-6. Sixth Modification Fig. 14 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the sixth modified example. The vibration plate 33C of the sixth modified example shown in Fig. 14 has a recessed portion 330. The recessed portion 330 is a recess formed by removing a portion of the vibration plate 33C on the flow path forming substrate 32 side. In the illustrated example, the recessed portion 330 is provided in a first layer 331.

[0072] The recessed portion 330 has a recess 339 at a portion that is joined to the flow path forming substrate 32. The recessed portion 339 corresponds to an outer peripheral portion of the recessed portion 330, and is provided over the entire circumference of the recessed portion 330 in a planar view. The recessed portion 339 is a portion that overlaps with the flow path forming substrate 32 in a planar view. Providing the recessed portion 339 makes it possible to suppress fluctuations in compliance of the vibration plate 33 caused by an adhesive used in manufacturing the flow path forming substrate 32 adhering to the vibration plate 33C.

[0073] 2-7. Seventh Modification Fig. 15 is an enlarged plan view of a portion of the liquid jet head 3 of the seventh modified example. In the seventh modified example shown in Fig. 15, the wiring 38 is omitted, and the curvature control unit 5D has the function of the wiring 38. That is, the curvature control unit 5 and the wiring 38 of the first embodiment are formed integrally. Since the curvature control unit 5D has the function of the wiring 38, the wiring 38 and the curvature control unit 5 can be formed in one step. This simplifies the process.

[0074] 2-8. Eighth Modification Fig. 16 is an enlarged plan view of a portion of the liquid jet head 3 of the eighth modified example. In the eighth modified example shown in Fig. 16, a portion of the curvature control unit 5E is missing. The curvature control unit 5E is not a continuous film, and includes a missing portion. For this reason, in the illustrated example, the first portion 51 and the multiple third portions 53 are not connected. Furthermore, the second portion 52 and the multiple third portions 53 are not connected.

[0075] For example, when there is a step on the second electrode 342 or the wiring 38, it is preferable that the curvature control unit 5E is provided so as not to overlap the step in the Z2 direction. By providing the curvature control unit 5E discontinuously so as to avoid the step, the curvature control unit 5E can be formed on a flat surface. This makes it easy to form the curvature control unit 5E capable of controlling the curvature of the diaphragm 33 to a desired curvature.

[0076] 3. Second embodiment A second embodiment will be described. In the following exemplary embodiment, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0077] Fig. 17 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the second embodiment. Fig. 18 is an enlarged plan view of a portion of the liquid jet head 3. The liquid jet head 3 of the second embodiment has a piezoelectric actuator 34A instead of the piezoelectric actuator 34.

[0078] As shown in FIGS. 17 and 18, a piezoelectric actuator 34A differs from the piezoelectric actuator 34 of the first embodiment in that a first electrode 341A is a common electrode and a second electrode 342A is an individual electrode.

[0079] The first electrode 341A is a band-shaped common electrode extending along the Y axis so as to be continuous across the multiple piezoelectric actuators 34A. A predetermined reference voltage is applied to the first electrode 341A. Therefore, the piezoelectric actuator 34A on the left side in FIG. 17 and the piezoelectric actuator 34A on the right side in FIG. 17 have a common first electrode 341A. The first electrode 341A is similar to the first electrode 341 of the first embodiment, except that it is a common electrode.

[0080] The second electrodes 342A are individual electrodes formed at a distance from each other for each piezoelectric actuator 34A. A drive signal with a fluctuating voltage is applied to the second electrodes 342A. The second electrodes 342A are similar to the second electrodes 342 of the first embodiment, except that they are individual electrodes.

[0081] Furthermore, the piezoelectric actuator 34A includes an insulating section 345 having insulating properties. The insulating section 345 is provided on the upper surface of the second electrode 342A in the Z2 direction. The insulating section 345 is provided so as to cover the piezoelectric layer 343. The curvature control section 5 is disposed on the insulating section 345. Therefore, the piezoelectric layer 343 and the curvature control section 5 are electrically insulated from each other. This prevents the electrical influence of the curvature control section 5 on the piezoelectric layer 343.

[0082] In addition, in this embodiment, the insulating section 345 also functions as a waterproof section having waterproof properties. By providing such insulating section 345, it is possible to suppress the intrusion of moisture into the piezoelectric layer 343. Note that the insulating section 345 does not necessarily have the function of a waterproof section. Also, a waterproof section may be provided instead of the insulating section 345.

[0083] In the second embodiment, similarly to the first embodiment, the curvature control unit 5 is provided, so that it is possible to control the curvature of the vibration plate 33. Therefore, it is possible to exhibit high ejection performance.

[0084] 4. Modification of the Second Embodiment The second embodiment may be modified in various ways. For example, specific modified aspects that may be applied to the second embodiment are illustrated below. Two or more aspects arbitrarily selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0085] 4-1. 9th modified example 19 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the ninth modified example. The curvature control unit 5F of the eighth modified example shown in FIG. 19 overlaps with the pressure chamber C1 when viewed from the Z2 direction. Therefore, the plane area of ​​the curvature control unit 5F is larger than the plane area of ​​the curvature control unit 5 of the second embodiment described above. Therefore, the curvature control unit 5F is provided over a wider range than the curvature control unit 5 of the second embodiment described above. Therefore, the curvature control unit 5F can more strongly control the curvature of the vibration plate 33.

[0086] However, when viewed from the Z2 direction, the curvature control unit 5F does not overlap with the active unit 3430 of the piezoelectric layer 343. Therefore, according to the ninth modification, the effect of the curvature control unit 5F on the fluctuation of the diaphragm 33 is suppressed, and the curvature of the diaphragm 33 can be more easily controlled.

[0087] When viewed from the Z2 direction, the curvature control section 5F may overlap the active section 3430 of the piezoelectric layer 343. In this case, the curvature of the diaphragm 33 can be controlled more strongly.

[0088] 4-2. 10th modified example 20 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the tenth modified example. The liquid jet head 3 of the tenth modified example shown in FIG. 20 further includes a pressing unit 7 that presses a partition wall of the flow path forming substrate 32. The pressing unit 7 is connected to, for example, the sealing body 35 and protrudes from the sealing body 35 toward the flow path forming substrate 32. The pressing unit 7 is provided on the upper surface of the curvature control unit 5 in the Z2 direction. The curvature control unit 5 overlaps with the pressing unit 7 in the Z2 direction. By overlapping the curvature control unit 5 with the pressing unit 7, it is easier to increase the plane area of ​​the curvature control unit 5 compared to a case where they do not overlap. For this reason, it is easier to control the curvature of the vibration plate 33 by the curvature control unit 5.

[0089] 4-3. 11th modified example FIG. 21 is a cross-sectional view of an enlarged portion of the liquid jet head 3 of the eleventh modified example. The liquid jet head 3 of the eleventh modified example shown in FIG. 21 includes a pressing portion 7A that presses a partition wall of the flow path forming substrate 32. The pressing portion 7A is connected to, for example, the sealing body 35 and protrudes from the sealing body 35 toward the flow path forming substrate 32. The pressing portion 7A is not provided on the upper surface of the curvature control portion 5G in the Z2 direction, and is provided at a different position from the curvature control portion 5G when viewed in the Z2 direction. Therefore, the curvature control portion 5G does not overlap with the pressing portion 7A in the Z2 direction. Since the pressing portion 7A does not overlap with the curvature control portion 5G, the pressing portion 7A does not press the curvature control portion 5. For this reason, the presence of the pressing portion 7A is unlikely to affect the control of the curvature of the vibration plate 33 by the curvature control portion 5G. It is possible to suppress interference between the functions of the pressing portion 7A and the curvature control portion 6G.

[0090] 4-4. 12th modified example Fig. 22 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the twelfth modified example. The curvature control unit 5H of the twelfth modified example shown in Fig. 22 is provided inside the vibration plate 33 in the Z2 direction. Therefore, compared to the second embodiment described above, it is possible to suppress interference of the curvature control unit 5H with the structure of the piezoelectric actuator 34. In addition, since the curvature control unit 5H can be provided on a flat layer of the vibration plate 33, the curvature control unit 5H can be easily manufactured.

[0091] 4-5. 13th Modification Fig. 23 is an enlarged cross-sectional view of a portion of the liquid jet head 3 according to the thirteenth modified example. The vibration plate 33A according to the thirteenth modified example shown in Fig. 23 is similar to that of the fourth modified example described above. The vibration plate 33A is formed of a laminate including a first layer 331, an adhesion layer 333, and a second layer 332. The adhesion layer 333 is disposed between the first layer 331 and the second layer 332 to enhance adhesion therebetween.

[0092] 4-6. 14th Modification Fig. 24 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the fourteenth modified example. The vibration plate 33B of the fourteenth modified example shown in Fig. 24 is similar to that of the fourth modified example described above. The vibration plate 33B is formed of a laminate including a first layer 331, a first functional layer 334, an adhesion layer 333, a second functional layer 335, and a second layer 332.

[0093] 4-7. 15th Modification Fig. 25 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the fifteenth modified example. The vibration plate 33C of the fifteenth modified example shown in Fig. 25 has a recessed portion 330. The recessed portion 330 is similar to that of the sixth modified example described above. The recessed portion 330 is a recess formed by removing a portion of the vibration plate 33C on the flow path forming substrate 32 side. The recessed portion 330 includes a recess 339.

[0094] 4-8. 16th Variation Fig. 26 is an enlarged cross-sectional view of a portion of the liquid jet head 3 of the sixteenth modified example. The insulating portion 345B of the sixteenth modified example shown in Fig. 26 has a plurality of openings H1. Each opening H1 is formed corresponding to the second electrode 342A when viewed in the Z2 direction, and overlaps with the second electrode 342A when viewed in the Z2 direction. By having the openings H1, the active portion 3430 becomes more likely to move, and as a result, the vibration plate 33 becomes more likely to move.

[0095] 4-9. 17th Variation Fig. 27 is an enlarged plan view of a portion of the liquid jet head 3 of the seventeenth modified example. In the seventeenth modified example shown in Fig. 27, a portion of the curvature control unit 5I is missing. The curvature control unit 5I is not a continuous film, and includes a missing portion. For this reason, in the illustrated example, the first portion 51 and the multiple third portions 53 are not connected. Furthermore, the second portion 52 and the multiple third portions 53 are not connected.

[0096] For example, when there is a step on the insulating part 345, it is preferable that the curvature control part 5I is provided so as not to overlap the step in the Z2 direction. By providing the curvature control part 5I discontinuously so as to avoid the step, the curvature control part 5I can be formed on a flat surface. This makes it easy to form the curvature control part 5I that can control the curvature of the diaphragm 33 to a target curvature.

[0097] 5. Other Modifications The first embodiment, the second embodiment, and the first to seventeenth modified examples exemplified above may be modified in various ways. Specific modified aspects that may be applied to the above-described embodiments are exemplified below. Two or more aspects arbitrarily selected from the following examples may be appropriately combined within a range that is not mutually contradictory.

[0098] The "liquid jet head" may be a circulation type head having a so-called circulation flow path.

[0099] An "image forming apparatus" may be employed in various devices such as facsimile machines and copy machines, in addition to devices dedicated to printing. The uses of an image forming apparatus are not limited to printing. For example, an image forming apparatus that sprays a solution of a coloring material is used as a manufacturing apparatus that forms color filters for display devices such as liquid crystal display panels. Also, an image forming apparatus that sprays a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes for wiring boards. Also, an image forming apparatus that sprays a solution of an organic substance related to a living organism is used as a manufacturing apparatus that manufactures biochips, for example.

[0100] Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above embodiment. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above embodiment, and any configuration can be added. [Explanation of symbols]

[0101] 3...Liquid jet head, 5...Curvature control section, 5A...Curvature control section, 5B...Curvature control section, 5C...Curvature control section, 5D...Curvature control section, 5E...Curvature control section, 5F...Curvature control section, 5G...Curvature control section, 5H...Curvature control section, 5I...Curvature control section, 7...Pressing section, 7A...Pressing section, 9...Liquid container, 20...Control unit, 22...Medium conveying mechanism, 24...Moving mechanism, 31...Substrate, 32...Flow path forming substrate, 32a...Surface, 33...Vibration plate, 33A...Vibration plate, 33B...Vibration plate, 33C...Vibration plate, 33a...Surface, 34...Piezoelectric actuator, 34A...Piezoelectric actuator, 35...Sealing body, 36...Housing section, 37...Nozzle plate, 38...Wiring, 39...Vibration absorber, 40...Wiring substrate, 51...First part, 52...Second part, 53...Third part, 90...Medium, 1 00...image forming apparatus, 242...conveyor, 244...conveyor belt, 312...supply flow path, 314...communicating flow path, 320...edge, 330...recessed portion, 331...first layer, 332...second layer, 333...adhesive layer, 334...first functional layer, 335...second functional layer, 339...recess, 3430...active portion, 341...first electrode, 341A...first electrode, 342...second electrode, 342A...second electrode Electrode, 343...piezoelectric layer, 345...insulating portion, 353...space, 361...supply port, 362...space, 381...first conductive layer, 382...second conductive layer, 443...piezoelectric, A1...bidirectional arrow, A2...arrow, A3...arrow, C1...pressure chamber, G...notch, H1...opening, La...first row, Lb...second row, N...nozzle, R...liquid storage chamber, Ra...space, Rb...relay liquid chamber, Rc...space.

Claims

1. a flow path forming substrate having pressure chambers partitioned by partition walls; a vibration plate provided on one surface side of the flow path forming substrate; a piezoelectric actuator including a first electrode, a piezoelectric layer, and a second electrode, the first electrode being provided along a first direction from one surface side of the vibration plate; a curvature control unit capable of controlling a curvature of the vibration plate, the curvature control unit overlapping with the vibration plate when viewed from the first direction and being provided along an edge of the pressure chamber; A liquid jet head comprising:

2. 2. The liquid jet head according to claim 1, the curvature control portion does not overlap with an active portion of the piezoelectric layer sandwiched between the first electrode and the second electrode when viewed from the first direction. A liquid jet head comprising:

3. 3. The liquid jet head according to claim 2, The curvature control section does not overlap with the pressure chamber when viewed from the first direction. A liquid jet head comprising:

4. 2. The liquid jet head according to claim 1, The curvature control section overlaps with the pressure chamber when viewed from the first direction. A liquid jet head comprising:

5. 2. The liquid jet head according to claim 1, the curvature control portion overlaps with an active portion of the piezoelectric layer sandwiched between the first electrode and the second electrode when viewed from the first direction. A liquid jet head comprising:

6. 2. The liquid jet head according to claim 1, The curvature control portion is provided inside the diaphragm in the first direction. A liquid jet head comprising:

7. 6. The liquid jet head according to claim 1, a second piezoelectric actuator having the second electrode in common with the piezoelectric actuator; The curvature control unit is provided on an upper surface of the second electrode in the first direction. A liquid jet head comprising:

8. 6. The liquid jet head according to claim 1, a second piezoelectric actuator having the first electrode in common with the piezoelectric actuator; the piezoelectric actuator includes an insulating portion or a waterproof portion provided on an upper surface of the second electrode in the first direction, The curvature control part is provided on an upper surface of the insulating part or an upper surface of the waterproof part in the first direction. A liquid jet head comprising:

9. 9. The liquid jet head according to claim 8, a pressing portion that presses the partition wall of the flow path forming substrate, The curvature control portion overlaps with the pressing portion in the first direction. A liquid jet head comprising:

10. 9. The liquid jet head according to claim 8, a pressing portion that presses the partition wall of the flow path forming substrate, The curvature control portion does not overlap with the pressing portion in the first direction. A liquid jet head comprising:

Images