Liquid discharge head

Abstract

To provide a liquid discharge head that can easily secure variations.SOLUTION: A liquid discharge head according to one embodiment comprises a vibration plate oppositely arranged in a pressure chamber, and an actuator part, at least a portion of which is oppositely arranged in the vibration plate, and which has a laminate piezoelectric body in which a plurality of piezoelectric body layers and a plurality of electrodes are laminated. In the actuator part, at least a portion of an outer peripheral edge of an electrode laminate part in which the plurality of electrodes are laminated overlaps with an outer peripheral edge of a contact region where the pressure chamber contacts the vibration plate or at least the portion of the outer peripheral edge of the electrode laminate part protrudes to the outside of a pressure region when viewed from a normal direction of a surface on which the pressure chamber contacts the vibration plate. A cross section, which is orthogonal to the normal direction, of the actuator part falls inside the contact region, in a range whose thickness is the same as a thickness of the vibration plate, from an end part at the vibration plate side thereof.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a liquid ejection head. [Background technology]

[0002] In a liquid ejection head such as an inkjet head, a method is used in which a vibration plate is deformed using an actuator made of a piezoelectric material such as PZT, thereby deforming a pressure chamber facing the vibration plate and ejecting ink from a nozzle communicating with the pressure chamber. For example, a liquid ejection head includes an actuator member having a plurality of driving elements, which is made of a laminated piezoelectric material in which a plurality of electrodes and piezoelectric layers are laminated, and a flow path portion including a vibration plate disposed opposite the actuator member and which forms a plurality of pressure chambers and a predetermined flow path.

[0003] For example, the actuator has grooves machined into a laminated piezoelectric member, and multiple piezoelectric elements are formed in parallel. When a voltage is applied to the piezoelectric element to be driven, the ink in the pressure chamber facing the piezoelectric element is vibrated, and ink droplets are ejected from a nozzle communicating with the pressure chamber.

[0004] In such a laminated piezoelectric member, it is required that the amount of fluctuation is large. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5668382 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a liquid ejection head that can easily ensure a sufficient amount of deformation. [Means for solving the problem]

[0007] A liquid ejection head in one embodiment includes a vibration plate disposed opposite a pressure chamber, and an actuator section having a laminated piezoelectric body in which a plurality of piezoelectric layers and a plurality of electrodes are laminated, at least a portion of which is disposed opposite the vibration plate, wherein in the actuator section, when viewed in a normal direction to a surface where the pressure chamber and the vibration plate contact, at least a portion of the outer periphery of an electrode laminate section in which a plurality of electrodes are laminated overlaps with or is disposed outside the outer periphery of a contact area where the pressure chamber and the vibration plate contact, and wherein a cross section of the actuator section perpendicular to the normal direction is within the contact area within a thickness range equal to the thickness of the vibration plate from the end on the vibration plate side. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of an inkjet head according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the configuration of the inkjet head. [Diagram 3] FIG. 2 is an explanatory diagram showing the dimensional relationship of the inkjet head. [Figure 4] FIG. 2 is an explanatory diagram showing a schematic configuration of an inkjet recording apparatus including the inkjet head. [Diagram 5] FIG. 11 is a cross-sectional view showing the configuration of an inkjet head according to another embodiment. [Figure 6] FIG. 2 is an explanatory diagram showing the dimensional relationship of the inkjet head. [Figure 7] 6 is an explanatory diagram showing the configuration and dimensional relationship of an inkjet head according to another embodiment. FIG. [Figure 8] FIG. 2 is an explanatory diagram illustrating an example of an inkjet head. [Figure 9] FIG. 4 is an explanatory diagram showing a state in which a diaphragm in an example of an inkjet head is deformed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An inkjet head 1, which is a liquid ejection head according to the first embodiment, and an inkjet recording device 100, which is a liquid ejection device, will be described below with reference to FIGS. 1 to 4. FIGS. 1 and 2 are cross-sectional views showing a schematic configuration of the inkjet head 1. FIG. 3 is an explanatory diagram showing the dimensions and arrangement of the actuator portion 20, the vibration plate 30, and the pressure chamber 81 of the inkjet head 1. In FIG. 3, a cross-sectional view perpendicular to the X direction and a cross-sectional view perpendicular to the Z direction are shown side by side for the sake of explanation. FIG. 4 is an explanatory diagram showing a schematic configuration of an inkjet recording device. In the figure, arrows X, Y, and Z indicate three directions perpendicular to each other. In this embodiment, X is the parallel direction of the nozzles 51 and the pressure chambers 81, Y is the extension direction, and Z is along the axial direction of the nozzles. In each figure, the configuration is enlarged, reduced, or omitted as appropriate for the sake of explanation.

[0010] 1 and 2, the inkjet head 1 includes a base 10, an actuator section 20, a vibration plate 30, a flow path section 40 having a flow path substrate 41 and a frame section 45 as flow path members, a nozzle plate 50 as a nozzle section having a plurality of nozzles 51, and a drive circuit 70. As an example, in this embodiment, the inkjet head 1 shows an example in which the stacking direction of the piezoelectric layer 211, the vibration direction of the piezoelectric element 21, and the vibration direction of the vibration plate 30 are all along the Z direction. In this embodiment, on the back side of the nozzle plate 50, the vibration plate 30 and the flow path section 40 form a flow path structure section that forms a head flow path 80 in the head.

[0011] The actuator section 20 includes, for example, a laminated piezoelectric element 201 and a spacer member 202 .

[0012] The laminated piezoelectric element 201 is made of a piezoelectric material and includes a plurality of driving piezoelectric elements 21 and a plurality of non-driving piezoelectric elements 22 as actuators that are divided by grooves 23 and arranged alternately along the column direction, and a piezoelectric structure portion 24 that connects these multiple piezoelectric elements 21, 22 together.

[0013] In this embodiment, a nozzle 51 is provided at the center of the extension direction of the actuator section 20, and the actuator section 20 has a structure in which one side and the other side are symmetrical with respect to the nozzle 51. The actuator section 20 is bonded to one side of the base 10. The actuator section 20 is bonded to the base 10, for example.

[0014] In the actuator section 20, the driving piezoelectric elements 21 and the non-driven piezoelectric elements 22 are arranged in parallel at regular intervals. As an example, the driving piezoelectric elements 21 and the non-driven piezoelectric elements 22 are all configured in the shape of a rectangular parallelepiped column with the same external shape. The actuator section 20 is divided into multiple sections by multiple grooves 23, and the driving piezoelectric elements 21 and the non-driven piezoelectric elements 22 are all arranged in a row at the same pitch by grooves 23 of the same width.

[0015] For example, the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are each configured in a rectangular shape in a planar view seen from the Z direction, which is the axial direction of the nozzle, with the short side direction aligned with the row direction (X direction) of the element row and the long side direction aligned with the extension direction (Y direction) perpendicular to the row direction (X direction) and the stacking direction (Z direction).

[0016] The driving piezoelectric elements 21 are arranged in positions in the Z direction facing the multiple pressure chambers 81 formed in the flow path portion 40 and separated by the partition portion 42. As an example, the center positions in the row direction and extension direction of the driving piezoelectric elements 21 and the center positions in the row direction and extension direction of the pressure chambers 81 are arranged side by side in the Z direction.

[0017] The non-driven piezoelectric elements 22 are arranged in positions in the Z direction facing the partition walls 42 formed in the flow path section 40. As an example, the center positions in the row direction and extension direction of the non-driven piezoelectric elements 22 and the center positions in the row direction and extension direction of the partition walls 42 are arranged side by side in the Z direction.

[0018] The laminated piezoelectric body 201 is formed by stacking and sintering sheet-shaped piezoelectric materials. The actuator section 20 is formed by dicing the laminated piezoelectric body 201 from one end face to form grooves 23, thereby forming a plurality of rectangular columnar piezoelectric elements at predetermined intervals. Then, electrodes and the like are provided on the formed columnar elements, and a plurality of driving piezoelectric elements 21 and a plurality of non-driving piezoelectric elements 22 are formed, which are arranged alternately. The plurality of driving piezoelectric elements 21 and the plurality of non-driving piezoelectric elements 22 are arranged in parallel alternately with the grooves 23 in between in the column direction.

[0019] The piezoelectric members constituting the driving piezoelectric element 21 and the non-driven piezoelectric element 22 are, for example, laminated piezoelectric elements. The driving piezoelectric element 21 and the non-driven piezoelectric element 22 each include a plurality of laminated piezoelectric layers 211 and internal electrodes 221, 222 formed on the main surface of each piezoelectric layer 211. As an example, the driving piezoelectric element 21 and the non-driven piezoelectric element 22 have the same laminated structure. The driving piezoelectric element 21 includes external electrodes 223, 224 formed on the surface.

[0020] The piezoelectric layer 211 is formed in a thin plate shape from a piezoelectric material such as PZT (lead zirconate titanate) or lead-free KNN (potassium sodium niobate). The multiple piezoelectric layers 211 are laminated with their thickness direction aligned with the lamination direction and are bonded to each other. For example, in this embodiment, the thickness direction and lamination direction of the piezoelectric layers 211 are arranged along the vibration direction (Z direction).

[0021] The internal electrodes 221 and 222 are conductive films formed into a predetermined shape using a sinterable conductive material such as silver palladium. The internal electrodes 221 and 222 are formed in a predetermined region on the main surface of each piezoelectric layer 211. The internal electrodes 221 and 222 have different polarities. For example, one internal electrode 221 is formed in a region that reaches one end of the piezoelectric layer 211 but does not reach the other end of the piezoelectric layer 211 in the extension direction (Y direction) that is perpendicular to both the row direction (X direction) in which the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are arranged and the vibration direction (Z direction). The other internal electrode 222 is formed in a region that does not reach one end of the piezoelectric layer 211 but reaches the other end of the piezoelectric layer 211 in the extension direction. The internal electrodes 221 and 222 are connected to external electrodes 223 and 224 formed on the side surfaces of the piezoelectric elements 21 and 22, respectively.

[0022] That is, as shown in FIG. 3, the laminated piezoelectric body 201 has an electrode laminate portion 25 in which at least one of the electrodes 221, 222 is laminated, and the electrode laminate portion 25 has an electrode opposing portion 26 in the center in which the electrodes 221, 222 of different polarities are opposed to each other in the stacking direction, and has electrode non-opposing portions 27 on both sides of the electrode opposing portion 26 in which only the electrodes 221 or the electrodes 222 of the same polarity are laminated, and the electrodes 221, 222 of different polarities are not opposed to each other.

[0023] Furthermore, the laminated piezoelectric body 201 constituting the driving piezoelectric element 21 and the non-driving piezoelectric element 22 may further include a dummy layer on either or both of the ends on the nozzle plate 50 side and the opposite side. For example, the dummy layer is made of the same material as the piezoelectric layer 211, has an electrode on only one side, and is not deformed because no electric field is applied. For example, the dummy layer does not function as a piezoelectric body, but serves as a base for fixing the actuator section 20 to the base 10, or serves as a polishing allowance for polishing to achieve precision during and after assembly.

[0024] The external electrodes 223, 224 are formed on the surfaces of the multiple driving piezoelectric elements 21, and are formed by collecting the ends of the internal electrodes 221, 222. For example, the external electrodes 223, 224 are formed on one end face and the other end face in the extension direction of the piezoelectric layer 211, respectively. The external electrodes 223, 224 are formed by a known method such as plating or sputtering, using Ni, Cr, Au, or the like. The external electrodes 223 and 224 have different polarities. The external electrodes 223 and 224 are disposed on different side portions of the multiple driving piezoelectric elements 21, respectively. The external electrodes 223 and 224 may be disposed in different regions of the same side portion of the multiple driving piezoelectric elements 21.

[0025] In this embodiment, as an example, the external electrode 223 is an individual electrode, and the external electrode 224 is a common electrode. The external electrodes 223 serving as individual electrodes of the multiple driving piezoelectric elements 21 are arranged independently of each other, with the electrode layers divided by the grooves 23. The external electrode 224 serving as a common electrode has electrode layers connected to each other, for example, on the side surfaces of the piezoelectric structure 24, and is, for example, grounded. The external electrodes 223, 224 are connected to the driving circuit 70, for example, via a wiring film. For example, each of the external electrodes 223, 224 is connected to the control unit 116 as a driving unit via a driving IC 72 of the driving circuit 70, and is configured to be drive-controllable by the control of the control circuit 1161. The common electrode and the individual electrodes may be arranged in reverse.

[0026] The vibration direction of each of the piezoelectric elements 21 and 22 is along the stacking direction, and when an electric field is applied, they are displaced in the d33 direction.

[0027] The spacer member 202 constitutes a part of the actuator section 20 on the vibration plate 30 side. The spacer member 202 is disposed between the laminated piezoelectric body 201 and the vibration plate 30. The spacer member 202 is configured to have smaller dimensions than the laminated piezoelectric body 201 in the parallel direction and the extension direction.

[0028] The spacer members 202 are, for example, plate-shaped members formed separately from the laminated piezoelectric element 201, and are disposed opposite each of the piezoelectric elements.

[0029] At least a portion of the actuator section 20, which is composed of the laminated piezoelectric element 201 and the spacer member 202, is disposed opposite the vibration plate 30. That is, in this embodiment, the spacer member 202 faces the vibration plate 30 and is bonded thereto.

[0030] In the inkjet head 1, the driving piezoelectric element 21 vibrates when a voltage is applied to the internal electrodes 221, 222 via the external electrodes 223, 224. In this embodiment, the driving piezoelectric element 21 vibrates longitudinally along the stacking direction of the piezoelectric layer 211. The longitudinal vibration here means, for example, "vibration in the thickness direction defined by the piezoelectric constant d33." The driving piezoelectric element 21 displaces the vibration plate 30 and deforms the pressure chamber 81 by the longitudinal vibration.

[0031] The vibration plate 30 extends along a plane perpendicular to the Z direction, which is the vibration direction, and is bonded to one side of the vibration direction of the piezoelectric layer 211 of the plurality of piezoelectric elements 21, 22, i.e., the surface on the nozzle plate 50 side. The vibration plate 30 faces the plurality of nozzles 51 through the pressure chambers 81 in the Z direction, which is the vibration direction. The vibration plate 30 is configured to be deformable, for example. The vibration plate 30 is bonded to the driving piezoelectric element 21 and the non-driving piezoelectric element 22 of the actuator section 20 and to the frame section 45. For example, the vibration plate 30 has a vibration region 31 facing the piezoelectric elements 21, 22, and a support region 32 facing the frame section 45. The vibration plate 30 is provided between the flow path substrate 41 and the actuator section 20 in the vibration direction.

[0032] The vibration region 31 is, for example, in the form of a flat plate arranged such that the thickness direction coincides with the vibration direction of the piezoelectric layer 211. The vibration plate 30 has a surface direction extending in the arrangement direction of the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22. The vibration plate 30 is, for example, a metal plate. The vibration plate 30 has multiple vibration parts that face each pressure chamber 81 and are individually displaceable.

[0033] As an example, the vibration plate 30 is made of a nickel or SUS plate, and the thickness dimension along the vibration direction is set to about 5 μm to 15 μm. The vibration region 31 may have folds or steps formed in the regions adjacent to the vibration regions or between adjacent vibration regions so that the multiple vibration regions can be easily displaced. The vibration region 31 is deformed by the displacement of the region disposed opposite the driving piezoelectric element 21 due to the expansion and compression of the driving piezoelectric element 21. For example, the vibration plate 30 is formed by electroforming or the like. The vibration plate 30 is joined to the end face of the actuator section 20 by adhesive or the like.

[0034] The support region 32 is a plate-like member disposed between the frame portion 45 and the flow path substrate 41. The vibration plate 30 has a structure in which one side and the other side in the Y direction are symmetrical with respect to the nozzle 51 at the center.

[0035] The flow path section 40 includes a manifold section 44 that is configured with a plurality of flow path substrates 41 provided between the vibration plate 30 and the nozzle plate 50 , and a frame section 45 that is provided on the outer periphery of the actuator section 20 .

[0036] The flow path substrate 41 constitutes a plurality of partition walls 42 that separate the plurality of individual flow paths, and guide walls 43 that constitute each of the individual flow paths.

[0037] For example, the partition portion 42 is a wall member that separates the multiple pressure chambers 81 arranged in the parallel direction and separates the multiple individual flow paths arranged in the parallel direction. The partition portion 42 is disposed opposite the non-driven piezoelectric element 22 via the vibration plate 30 and is supported by the non-driven piezoelectric element 22.

[0038] The guide wall 43 is a wall member that constitutes the supply-side individual flow passages 82 and the discharge-side individual flow passages 84. For example, the guide wall 43 may have a step portion that narrows the cross-sectional area of ​​the flow passage at a predetermined location.

[0039] The flow path substrate 41 has a structure in which one side and the other side in the Y direction are symmetrical with respect to the nozzle 51. Specifically, the partition walls 42 have a structure in which one side and the other side are symmetrical with respect to the Y direction with respect to the nozzle 51, and for example, the partition walls 42 extend along the Y direction and have a uniform cross-sectional shape perpendicular to the Y direction. Also, the guide walls 43 have a structure in which one side and the other side are symmetrical with respect to the nozzle 51, and for example, the guide walls 43 extend along the Y direction and have a uniform cross-sectional shape perpendicular to the Y direction at the same position with respect to the nozzle.

[0040] The frame portion 45 is a structure that is joined to the vibration plate 30 together with the piezoelectric elements 21 and 22. In this embodiment, the frame portion 45 is disposed adjacent to the actuator portion 20, and constitutes the outer periphery of the inkjet head 1.

[0041] In this embodiment, the frame portion 45 is joined to the back side of the diaphragm 30. The frame portion 45, together with the diaphragm 30 and the flow path substrate 41, form a supply side common chamber 83 and a discharge side common chamber 85.

[0042] In this embodiment, the vibration plate 30 and the flow path section 40 form a head flow path 80 in the inkjet head 1. The head flow path 80 includes a plurality of pressure chambers 81, a supply side flow path, and a discharge side flow path. The supply side flow path has a plurality of supply side individual flow paths 82 extending in one direction of the pressure chamber 81, and a supply side common chamber 83 communicating with one side of the plurality of supply side individual flow paths 82. The discharge side flow path has a plurality of discharge side individual flow paths 84 extending to the other side of the pressure chamber 81, and a discharge side common chamber 85 communicating with the other side of the plurality of discharge side individual flow paths 84. In this embodiment, when viewed from the Z direction, the supply side individual flow paths 82, the pressure chamber 81, and the discharge side individual flow paths 84 are arranged side by side in the extension direction which is the flow direction.

[0043] The pressure chambers 81 are spaces formed on one side of the vibration region 31 of the vibration plate 30, and communicate with a supply side common chamber 83 and a discharge side common chamber 85 via supply side individual flow paths 82 and discharge side individual flow paths 84 formed on the supply side and discharge side, respectively. The pressure chambers 81 are separated by the partition wall 42. That is, both sides of the pressure chambers 81 in the parallel direction (X direction) are formed by the partition wall 42. Each pressure chamber 81 communicates with a nozzle 51 formed in the nozzle plate 50 arranged on one side. The pressure chambers 81 are closed on the opposite side of the nozzle plate 50 by the vibration plate 30. The pressure chambers 81 are deformed by vibration of the vibration plate 30 that forms a part of the pressure chambers 81, and thus eject liquid from the nozzles 51.

[0044] Here, the positional relationship between the pressure chamber 81, the vibration plate 30, and the actuator section 20 will be described with reference to Fig. 3. In Fig. 3, for the sake of explanation, a side view and a plan view are shown side by side.

[0045] In the actuator section 20, when viewed from the normal direction of the surface where the pressure chamber 81 and the vibration plate 30 contact, the outer peripheral edge of the electrode laminate section 25 in which the internal electrodes 221, 222 of each element 21, 22 are laminated overlaps with the outer peripheral edge of the pressure region RB in which the pressure chamber 81 and the vibration plate 30 contact, or at least a portion of the outer peripheral edge of the pressure region RB protrudes outside. For example, the entire outer peripheral edge of the electrode laminate section 25 may be disposed outside the pressure region RB, or a portion of the outer peripheral edge of the electrode laminate section 25 may be disposed inside the pressure region RB. Also, the electrode laminate section 25 and the outer peripheral edge of the pressure region RB may overlap partially or entirely. In this embodiment, for example, the pressure region RB and the electrode laminated portion 25 have a rectangular outer periphery when viewed from the normal direction, and in the extension direction, the length Wa of the electrode laminated portion 25 is greater than the length Wd of the pressure region RB. Meanwhile, in the parallel direction, the width Ta of the electrode laminated portion 25 is smaller than the width Td of the pressure region RB. That is, in this embodiment, the electrode laminated portion 25 protrudes outside the pressure region RB in the extension direction, and the electrode laminated portion 25 is contained inside the pressure region RB in the parallel direction.

[0046] In addition, the actuator section 20 is disposed such that, in a range of thickness Ha equal to the thickness Ha of the vibration plate 30 from the end on the vibration plate 30 side, a cross section perpendicular to the normal direction of the contact surface is disposed inside the pressure region RB in which the pressure chamber 81 faces the vibration plate 30. That is, when the actuator section 20 is cut in a range from the end on the vibration plate 30 side of the vibration plate 30 to the thickness of the vibration plate 30, the projection region is shaped to be contained within the pressure region RB. In this embodiment, the spacer member 202 is thicker than the vibration plate 30, and the region of the spacer member 202 on the vibration plate 30 side that is the same thickness as the vibration plate 30 is configured to be shaped to be contained at least within the pressure region RB. That is, the maximum width Wc in the thickness range of the vibration plate 30 thickness from the contact surface of the actuator section 20 with the vibration plate 30 is smaller than the periphery of the surface where the pressure chamber 81 and the vibration plate 30 contact. For example, the maximum width Wc in the length range of the vibration plate 30 thickness Ha from the contact surface of the actuator section 20 with the vibration plate 30 is less than the length Wd of the pressure chamber 81 in the extension direction. For example, the pressure area RB and the spacer member 202 have rectangular outer edges when viewed from the normal direction, and in the extension direction, the length Wc of the spacer member 202 is equal to the length Wb of the contact area RA (opposing area) here and is smaller than the length Wd of the pressure area RB. Also, as shown in Fig. 2, in the parallel direction, the width Tc of the spacer member 202 is equal to the width Tb of the contact area RA and is smaller than the width Td of the pressure area RB.

[0047] Moreover, when viewed from the normal direction of the contact surface, at least a part or the whole of the non-electrode facing portions 27 of the actuator element 20 is provided outside the contact area RA. As an example, in this embodiment, both of the non-electrode facing portions 27 on both sides are provided outside the contact area RA.

[0048] That is, the length Wa of the electrode stack 25 in the extension direction is set to be equal to or greater than the length Wd of the pressure chamber 81 to ensure the size of the displacement portion. Also, by making the contact area RA, which is the contact portion between the actuator section 20 and the vibration plate 30, smaller than the pressure chamber 81, it is possible to prevent the deformation of the vibration plate 30 from being hindered by the partition wall.

[0049] Furthermore, by ensuring a portion smaller than the pressure chamber 81 within the range of height Ha equivalent to thickness Ha of the diaphragm 30, it is possible to prevent interference between the actuator section 20 and the diaphragm 30 when the diaphragm 30 deforms. Therefore, even if warping occurs in the diaphragm 30 or the flow path substrate 41 or the diaphragm 30 deforms, it is possible to prevent interference between the actuator section 20 and the diaphragm 30 outside the contact area RA, thereby improving the manufacturing yield.

[0050] The nozzle plate 50 is configured as a rectangular plate with a thickness of about 10 μm to 100 μm and made of a metal such as SUS or Ni or a resin material such as polyimide. The nozzle plate 50 is disposed on one side of the flow path substrate 41 so as to cover the openings of the pressure chambers 81 on one side.

[0051] A plurality of nozzles 51 are arranged in the same direction as the arrangement of the pressure chambers 81 to form a nozzle row. For example, the nozzles 51 are provided at positions corresponding to the plurality of pressure chambers 81, respectively. In this embodiment, the nozzles 51 are provided at central positions of the pressure chambers 81 in the extension direction.

[0052] The driving circuit 70 includes a wiring film having one end connected to the external electrodes 223 and 224, a driving IC 72 mounted on the wiring film 71, and a printed wiring board mounted on the other end of the wiring film 71.

[0053] The drive circuit 70 applies a drive voltage to the external electrodes 223 and 224 via the drive IC 72 to drive the drive piezoelectric element 21 , thereby increasing or decreasing the volume of the pressure chamber 81 and causing droplets to be ejected from the nozzle 51 .

[0054] The wiring film 71 is connected to the multiple external electrodes 223, 224. For example, the wiring film 71 is an ACF (anisotropic conductive film) that is fixed by thermocompression or the like to the connection portions of the external electrodes 223, 224. The wiring film 71 is, for example, a COF (chip on film) on which a driving IC 72 is mounted as an electronic component.

[0055] The driving IC 72 is connected to the external electrodes 223, 224 via the wiring film 71. The driving IC 72 is an electronic component used for ejection control. The driving IC 72 may be connected to the external electrodes 223, 224 by other means such as ACP (anisotropic conductive paste), NCF (non-conductive film), and NCP (non-conductive paste) instead of the wiring film 71.

[0056] The driving IC 72 generates a control signal and a driving signal for operating each driving piezoelectric element 21. The driving IC 72 generates a control signal for controlling the timing of ink ejection and the selection of the driving piezoelectric element 21 for ejecting ink according to an image signal input from the control unit 116 of the inkjet recording device 100 on which the inkjet head 1 is mounted. The driving IC 72 also generates a voltage to be applied to the driving piezoelectric element 21, i.e., a driving signal (electrical signal), according to a control signal from the control unit 116. When the driving IC 72 applies a driving signal to the driving piezoelectric element 21, the driving piezoelectric element 21 is driven to displace the vibration plate 30 and change the volume of the pressure chamber 81. As a result, the ink filled in the pressure chamber 81 generates pressure vibration. The pressure vibration causes ink to be ejected from the nozzle 51 provided in the pressure chamber 81. The inkjet head 1 may be configured to realize gradation expression by changing the amount of ink droplets that land on one pixel. The inkjet head 1 may also be configured to change the amount of ink droplets that land on one pixel by changing the number of times ink is ejected. In this manner, the driving IC 72 is an example of an application unit that applies a driving signal to the driving piezoelectric element 21.

[0057] For example, the drive IC 72 includes a data buffer, a decoder, and a driver. The data buffer stores print data for each drive piezoelectric element 21 in chronological order. The decoder controls the driver for each drive piezoelectric element 21 based on the print data stored in the data buffer. The driver outputs a drive signal that operates each drive piezoelectric element 21 based on the control of the decoder. The drive signal is, for example, a voltage applied to each drive piezoelectric element 21.

[0058] The printed wiring board is, for example, a PWA (Printing Wiring Assembly) on which various electronic components and connectors are mounted, and has a head control circuit. The printed wiring board is connected to a control unit 116 of the inkjet recording apparatus 100.

[0059] In the inkjet head 1 configured as above, the nozzle plate 50, the frame portion 45, the flow path substrate 41, and the diaphragm 30 form a head flow path 80 having a plurality of pressure chambers 81 communicating with the nozzle 51, a plurality of supply-side individual flow paths 82 communicating with each of the pressure chambers 81, a discharge-side individual flow paths 84 communicating with each of the pressure chambers 81, a supply-side common chamber 83 communicating with the plurality of supply-side individual flow paths 82, and a discharge-side common chamber 85 communicating with the plurality of discharge-side individual flow paths 84. The head flow path 80 is a side shooter type ink flow path in which ink flows from one side to the other side around the nozzle 51.

[0060] For example, the supply-side common chamber 83 communicates with an ink tank such as a cartridge through a supply-side ink flow path, and ink is supplied to each pressure chamber 81 through the supply-side common chamber 83. The discharge-side common chamber 85 communicates with an ink flow path on the recovery side, and ink discharged from the discharge-side common chamber 85 is returned to the ink tank through the ink flow path on the recovery side and circulates. All the driving piezoelectric elements 21 are connected by wiring so that a voltage can be applied. In the inkjet head 1, for example, the control unit 116 of the inkjet recording device 100 applies a driving voltage to the electrodes 221 and 222 through the driving IC 72, so that the driving piezoelectric element 21 to be driven vibrates, for example, in the stacking direction, that is, in the thickness direction of each piezoelectric layer 211. In other words, the driving piezoelectric element 21 vibrates vertically.

[0061] In the inkjet head 1, a driving voltage is applied to the internal electrodes 221, 222 of the driving piezoelectric element 21 to be driven, thereby selectively driving the driving piezoelectric element 21 to be driven. Then, the vibration plate 30 is deformed by combining the deformation in the tensile direction and the deformation in the compressive direction by the driving piezoelectric element 21 to be driven, and the volume of the pressure chamber 81 is changed, so that liquid is guided from the supply side common chamber 83 and ejected from the nozzle 51.

[0062] An example of an inkjet recording apparatus 100 equipped with the inkjet head 1 will now be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing a schematic configuration of an inkjet recording apparatus equipped with the inkjet head.

[0063] As shown in FIG. 4, the inkjet recording apparatus 100 includes a housing 111, a medium supply unit 112, an image forming unit 113, a medium discharge unit 114, a conveying device 115, and a control unit .

[0064] The inkjet recording device 100 is a liquid ejection device that performs an image formation process on paper P by ejecting liquid such as ink while transporting the paper P as a printing medium, which is the ejection target, along a predetermined transport path R from a medium supply section 112 through an image forming section 113 to a medium ejection section 114.

[0065] The housing 111 constitutes the outer shell of the inkjet recording apparatus 100. The housing 111 is provided at a predetermined location with an outlet for discharging the paper P to the outside.

[0066] The medium supply unit 112 includes a plurality of paper feed cassettes, and is configured to be able to hold a plurality of sheets of paper P of various sizes in a stack.

[0067] The medium discharge unit 114 includes a paper discharge tray configured to be able to hold the paper P discharged from the discharge opening.

[0068] The image forming section 113 includes a support section 117 that supports the paper P, and a plurality of head units 130 that are disposed above the support section 117 so as to face the support section 117.

[0069] The support section 117 includes a conveyor belt 118 provided in a loop shape in a predetermined area where image formation is performed, a support plate 119 supporting the conveyor belt 118 from the back side, and a plurality of belt rollers 120 provided on the back side of the conveyor belt 118.

[0070] During image formation, the support section 117 supports the paper P on a holding surface, which is the upper surface of the conveyor belt 118, and conveys the paper P downstream by feeding the conveyor belt 118 at a predetermined timing by the rotation of the belt roller 120.

[0071] The head unit 130 includes multiple (four colors) inkjet heads 1, ink tanks 132 as liquid tanks mounted on each inkjet head 1, a circulation flow path 133 connecting the inkjet heads 1 and the ink tanks 132, a supply pump 134, and a negative pressure control device 135.

[0072] In this embodiment, the system includes inkjet heads 1 of four colors, cyan, magenta, yellow, and black, and ink tanks 132 that respectively accommodate ink of each color. The ink tanks 132 are connected to the inkjet heads 1 by a circulation flow path 133. For example, the circulation flow path 133 includes a supply flow path and a recovery flow path, and the ink tanks 132, a supply pump 134, a negative pressure control device 135, and the inkjet heads 1 are provided midway along the circulation flow path 133.

[0073] The supply pump 134 is a liquid delivery pump constituted by, for example, a piezoelectric pump. The supply pump 134 is provided in a supply flow path. The supply pump 134 is connected to a control circuit 1161 of the control unit 116 by wiring and is configured to be controllable by the control unit 116. The supply pump 134 supplies liquid to the inkjet head 1.

[0074] For example, the negative pressure control device 135 is a pump or pressure adjustment device connected to the ink tank 132 or provided in the circulation flow path 133, and controls the negative pressure within the ink tank 132 or within the circulation flow path 133 in response to the water head value between the inkjet head 1 and the ink tank 132, thereby causing the ink supplied to each nozzle 51 of the inkjet head 1 to form a meniscus of a predetermined shape.

[0075] For example, the negative pressure control device 135 is a pump or a pressure regulator.

[0076] The conveying device 115 conveys the paper P along a conveying path R that runs from the medium supply unit 112 through the image forming unit 113 to the medium discharge unit 114. The conveying device 115 includes a plurality of guide plate pairs 121 and a plurality of conveying rollers 122 that are arranged along the conveying path R.

[0077] Each of the guide plate pairs 121 includes a pair of plate members disposed opposite each other with the paper P being transported therebetween, and guides the paper P along the transport path R.

[0078] The conveying rollers 122 are driven to rotate under the control of the control unit 116, thereby sending the paper P downstream along the conveying path R. Sensors for detecting the conveying status of the paper are disposed at various points along the conveying path R.

[0079] The control unit 116 includes a control circuit 1161 such as a CPU (Central Processing Unit) which serves as a controller, a ROM (Read Only Memory) which stores various programs, a RAM (Random Access Memory) which temporarily stores various variable data, image data, and the like, and an interface unit which inputs data from the outside and outputs data to the outside.

[0080] In the inkjet recording device 100 configured as above, when the control unit 116 detects a print instruction by a user operating an operation input unit, for example, in an interface, the control unit 116 drives the conveying device 115 to convey the paper P and outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 1. As a discharge operation, the inkjet head 1 sends a drive signal to the driving IC 72 by an image signal corresponding to image data, applies a drive voltage to the internal electrodes 221 and 222, and selectively drives the driving piezoelectric element 21 to be discharged, for example, to vibrate vertically in the stacking direction, and changes the volume of the pressure chamber 81 to discharge ink from the nozzle 51, thereby forming an image on the paper P held on the conveying belt 118. As a liquid discharge operation, the control unit 116 drives the supply pump 134 to supply ink from the ink tank 132 to the supply side common chamber 83 of the inkjet head 1.

[0081] Here, a driving operation for driving the inkjet head 1 will be described. The inkjet head 1 according to this embodiment includes driving piezoelectric elements 21 arranged to face the pressure chambers 81, and these driving piezoelectric elements 21 are connected by wiring so that a voltage can be applied thereto. The control unit 116 sends a driving signal to the driving IC 72 based on an image signal corresponding to image data, and applies a driving voltage to the internal electrodes 221, 222 of the driving piezoelectric elements 21 to be driven, thereby selectively deforming the driving piezoelectric elements 21 to be driven. Then, the volume of the pressure chambers 81 is changed by combining the deformation in the tensile direction and the deformation in the compressive direction of the vibration plate 30, thereby discharging liquid.

[0082] For example, the control unit 116 alternates between a pulling operation and a compression operation. In the inkjet head 1, during tension to increase the internal volume of the target pressure chamber 81, the driving piezoelectric element 21 to be driven is contracted, and the driving piezoelectric elements 21 that are not the driving target are not deformed. Also, during compression to decrease the internal volume of the target pressure chamber 81 in the inkjet head 1, the target driving piezoelectric element 21 is expanded. Note that the non-driven piezoelectric elements 22 are not deformed.

[0083] According to the inkjet head 1 and inkjet recording device 100 of the above-described embodiment, the amount of fluctuation can be ensured by making the width of the electrode stack portion 25 equal to or greater than the length of the pressure chamber 81. Furthermore, by making the contact area RA, which is the contact portion between the actuator portion 20 and the vibration plate 30, smaller than the pressure chamber 81, it is possible to prevent the deformation of the vibration plate 30 from being hindered by the partition wall, and it is easy to ensure the amount of fluctuation.

[0084] In other words, even if the actuator section is enlarged and the ratio of electrode facing parts to non-electrode facing parts is increased, if the outer perimeter of the surface where the vibration plate and actuator contact extends beyond the outer perimeter of the surface where the pressure chamber and vibration plate contact, even when the actuator expands and contracts, it will push into the entire pressure chamber, and fluctuations in the pressure chamber volume will be hindered. However, in this embodiment, when viewed from the normal direction of the contact surface where the vibration plate 30 and actuator section 20 contact, the outer perimeter of the area RA where the vibration plate 30 and actuator section 20 contact is configured to be inside the outer perimeter of the surface where the pressure chamber 81 and vibration plate 30 contact, thereby avoiding hinderance of fluctuation.

[0085] As a comparative example, as shown in FIG. 8, there is a method for providing a convex portion 10301 on the surface of the vibration plate 1030 in an area smaller than the outer periphery of the surface where the pressure chamber 1081 and the vibration plate 1030 contact each other by etching or the like as in the inkjet head 1000, but in this case, the deflection of the vibration plate 1030 becomes an issue. The inkjet head 1000 includes an actuator 1020 having an electrode laminated portion 1025 in which at least one of the electrodes 10221 and 10222 is laminated. The electrode laminated portion 1025 of the actuator 1020 has only the electrodes 10221 or 10221 of the same polarity laminated, and an electrode non-opposing portion 1027 in which the electrodes 10221 and 10222 of different polarities do not face each other is provided on both sides of a central electrode opposing portion 1026 in which the electrodes 10221 and 10222 of different polarities face each other in the lamination direction. FIG. 9 is an explanatory diagram showing an interference state when the vibration plate 1030 of the inkjet head 1000 is deformed. For example, if the thickness of the vibration plate 1030 is 10 μm, the thickness of the convex portion 10301 on the surface of the vibration plate 1030 cannot be made 10 μm or more thicker than the thickness of the vibration plate. In addition, the thinner the thickness of the vibration plate 1030, the easier it is to deform, so it is desirable to make the thickness of the vibration plate 1030 small. On the other hand, the electrode non-facing portion 1027 is, for example, 150 μm, and the longitudinal direction (extension direction) of the pressure chamber 1081 is often about 1 mm or more. Therefore, as shown in FIG. 9, it is necessary to manage the dimensions of various members and the manufacturing process so as to avoid a situation in which the entire flow channel 1080 constituting the pressure chamber 1081 bends and the vibration plate 1030 and the actuator 1020 come into contact with each other outside the outer periphery of the surface where the pressure chamber and the vibration plate 1030 come into contact with each other.

[0086] Therefore, in the above embodiment, by ensuring in the actuator section 20 a portion smaller than the pressure chamber 81 within a range of height Ha equivalent to the thickness Ha of the diaphragm 30, it is possible to prevent the actuator section 20 and the diaphragm 30 from interfering with each other when the diaphragm 30 deforms. Therefore, even if warping occurs in the diaphragm 30 or the flow path substrate 41 or if the diaphragm 30 deforms, it is possible to prevent the actuator section 20 and the diaphragm 30 from interfering with each other outside the contact area RA, and improve the manufacturing yield.

[0087] For example, when applying a potential difference to two types of surface electrodes to apply a potential to all the laminated electrodes, the non-opposing electrode portion does not deform even when a potential difference is applied, and the deformation of the opposing electrode portion is suppressed. Therefore, it is desirable that the ratio of the non-opposing electrode portion to the opposing electrode portion is small. On the other hand, in order to ensure the insulation of the two types of electrodes due to constraints such as manufacturing variations, the non-opposing electrode portion needs to have a certain length. For example, in the extension direction (Y direction), if the length of the non-opposing electrode portion is 150 μm on one side and the longitudinal length of the electrode laminated portion is 1000 μm, the opposing electrode portion is 70% of the longitudinal length of the electrode laminated portion. If the longitudinal length of the electrode laminated portion is halved to 500 μm, the opposing electrode portion is 40% of the longitudinal length of the electrode laminated portion. Therefore, if the longitudinal length of the electrode laminated portion is halved, the reduction in the longitudinal length of the electrode laminated portion as well as the reduction in the ratio of the opposing electrode portion to the non-opposing electrode portion will reduce the extrusion volume of the diaphragm by the actuator by more than the reduction rate of the longitudinal length of the electrode laminated portion.

[0088] In the above embodiment, by configuring the actuator so that a part or all of the electrode non-facing portion is located outside the outer perimeter (four sides in this embodiment) of the area RA of the contact surface between the actuator section 20 and the diaphragm 30, the ratio of the electrode facing portion 26 located inside the outer perimeter (four sides in this embodiment) of the contact surface between the actuator section 20 and the diaphragm 30 increases. This makes it possible to strengthen the force with which the actuator section 20 presses or pulls up the contact surface of the diaphragm 30.

[0089] More preferably, by configuring the entire non-electrode facing portion 27 of the actuator portion 20 to be located outside the outer periphery (in this embodiment, the four sides) of the contact surface between the actuator portion 20 and the diaphragm 30, the ratio of the electrode facing portion 26 to the non-electrode facing portion 27 becomes larger, and the amount of deformation of the diaphragm 30 can be increased.

[0090] The present invention is not limited to the above-described embodiment, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention.

[0091] For example, in the above embodiment, the plate-shaped spacer member 202 is provided on the vibration plate 30 side of the actuator section 20 separately from the laminated piezoelectric body 201, but the present invention is not limited to this. For example, a part of the vibration plate 30 side of the laminated piezoelectric body 201 of the actuator may be shaped so that the cross-sectional area perpendicular to the lamination direction is reduced. For example, the spacer member 202 may be integrally formed as a part of the piezoelectric body.

[0092] Also, a part of the actuator section 20 on the vibration plate 30 side may be cut out in a tapered shape to reduce the cross-sectional area of ​​the part in contact with the vibration plate 30. For example, the inkjet head 11 shown in Figs. 5 and 6 as another embodiment has a chamfered portion 203 in which a part of the laminated piezoelectric body 201 of the actuator section 20 is cut out in a tapered shape. Fig. 5 is a cross-sectional view of the inkjet head 11 according to another embodiment. Fig. 6 is an explanatory diagram showing the configuration and dimensional relationship of the inkjet head 11 according to another embodiment, and shows a cross-sectional view perpendicular to the X direction and a cross-sectional view perpendicular to the Z direction side by side. Also, in Figs. 5 and 6, the same reference numerals are used for the same configuration as the inkjet head 1 of the first embodiment.

[0093] In the inkjet head 11, when viewed from the normal opposite side of the surface where the pressure chambers 81 and the vibration plate 30 contact, the outer periphery of the electrode laminated portion 25 of the actuator portion 20 overlaps with the outer periphery of the pressure region RB where the pressure chambers 81 and the vibration plate 30 contact, or at least a portion of the outer periphery protrudes outside the outer periphery of the pressure region RB. For example, the entire outer periphery of the electrode laminated portion 25 may be disposed outside the pressure region RB, or a portion of the outer periphery of the electrode laminated portion 25 may be disposed inside the pressure region RB. The actuator element 20 is configured such that a cross section perpendicular to the normal direction within a range of thickness Ha that is the same dimension as the thickness Ha of the diaphragm 30 from the end on the diaphragm 30 side falls within the pressure region RB. Furthermore, when viewed from the normal direction of the contact surface where the pressure chamber 81 and the vibration plate 30 are in contact, at least a part or the whole of the non-electrode facing portion 27 of the actuator section 20 is provided outside the contact area RA where the actuator section 20 and the vibration plate 30 face each other.

[0094] In this embodiment, for example, if the longitudinal length Wd of the pressure chamber 81 in the extension direction is 720 μm, the chamfer angle of the contact surface side of the actuator section 20 with the vibration plate 30 is 45 degrees, and the thickness of the vibration plate 30 is 10 μm, then the longitudinal length Wb of the contact area RA (opposing area) of the contact surface between the actuator section 20 and the vibration plate 30 in the Y direction is less than 700 μm, and the longitudinal length Wa of the electrode laminate section 25 of the actuator section 20 is 720 μm or more. The other configurations are the same as those of the above embodiments.

[0095] In the above embodiment, the vibration plate 30 has a uniform thickness, but the present invention is not limited to this. For example, as in the inkjet head 12 shown in FIG. 7 as another embodiment, the vibration plate 30 may have a different thickness depending on the portion. FIG. 7 is an explanatory diagram showing the configuration and dimensional relationship of the inkjet head 12 according to another embodiment, and shows a cross-sectional view perpendicular to the X direction and a cross-sectional view perpendicular to the Z direction side by side. In FIG. 7, the same components as those of the inkjet heads 1 and 11 of the above embodiments are given the same reference numerals. In the inkjet head 12, the vibration plate 30 is configured such that the thickness of the facing portion 301 of the contact area RA is thicker than that of the outer portion, and the outer portion 302 around the contact area RA is thin. In this case, the cross section perpendicular to the stacking direction of the vibration plate 30 may be configured to fit inside the pressure area RB in the range of thickness Hb of the contact area RA of the vibration plate 30 from the end of the thin portion of the outer contact portion 302 on the actuator portion 20 side to the thickness Hb of the contact area RA of the vibration plate 30. The other configurations are the same as those of the above embodiments.

[0096] That is, in the inkjet head 12, when viewed from the normal direction of the surface where the pressure chamber 81 and the vibration plate 30 contact each other in the actuator section 20, the outer periphery of the electrode laminate section 25 overlaps with the outer periphery of the pressure region RB where the pressure chamber 81 faces the vibration plate 30, or at least a part of the outer periphery of the electrode laminate section 25 protrudes outside the outer periphery of the pressure region RB. For example, the entire outer periphery of the electrode laminate section 25 may be disposed outside the pressure region RB, or a part of the outer periphery of the electrode laminate section 25 may be disposed inside the pressure region RB. Also, the actuator section 20 is configured such that a cross section perpendicular to the normal direction fits inside the pressure region RB within a range of thickness Hb that is the same dimension as the thickness Hb of the contact region RA of the vibration plate 30 from the end of the thin-walled part of the outer contact portion 302 on the actuator section 20 side. Furthermore, when viewed from the normal direction of the contact surface where the pressure chamber 81 and the vibration plate 30 are in contact with each other, at least a part or the whole of the non-electrode facing portion 27 of the actuator section 20 is provided outside the contact area RA where the actuator section 20 and the vibration plate 30 face each other. The other configurations are the same as those of the above-mentioned embodiments.

[0097] The specific materials and configurations of the piezoelectric elements 21 and 22 in the above embodiment are not limited to those described above. In addition, the heat resistance temperature and upper voltage limit of the electronic components are also changed appropriately depending on the performance of the materials and components.

[0098] In the above embodiment, a plurality of piezoelectric layers are laminated, and the driving piezoelectric element 21 is driven by longitudinal vibration (d33) in the lamination direction, but the present invention is not limited to this. For example, the present invention can be applied to a configuration in which the driving piezoelectric element 21 is composed of a single layer of piezoelectric material, or to a configuration in which the driving element 21 is driven by lateral vibration displacing in the d31 direction.

[0099] The arrangement of the nozzles 51 and the pressure chambers 81 is not limited to that in the above embodiment. For example, the nozzles 51 may be arranged in two or more rows. Furthermore, air chambers serving as dummy chambers may be formed between the multiple pressure chambers 81.

[0100] In addition, the configurations and positional relationships of various components including the diaphragm 30, the flow path substrate 41, the nozzle plate 50, and the frame portion 45 are not limited to the above-mentioned examples, and can be changed as appropriate.

[0101] Furthermore, the liquid to be ejected is not limited to ink for printing, but may be, for example, a device that ejects liquid containing conductive particles for forming a wiring pattern on a printed wiring board.

[0102] In addition, in the above embodiment, the inkjet head 1 is used in a liquid ejection device such as an inkjet recording device, but the present invention is not limited to this and can also be used in, for example, 3D printers, industrial manufacturing machines, and medical applications, enabling reduction in size, weight, and cost.

[0103] According to at least one of the embodiments described above, a desired flow path shape can be easily set.

[0104] Although several other embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0105] 1...inkjet head, 20...actuator section, 21...driven piezoelectric element, 22...non-driven piezoelectric element, 23...groove, 24...piezoelectric structure section, 30...vibration plate, 31...vibration area, 40...flow path section, 41...flow path substrate, 42...partition wall section, 43...guide wall, 44...manifold section, 45...frame section, 50...nozzle plate, 51...nozzle, 70...drive circuit, 71...wiring film, 72...drive IC, 80...head flow path, 81...pressure chamber, 82...supply side individual flow path, 83...supply side common chamber, 84...discharge side individual flow path, 85...discharge side common chamber, 100...ink Jet recording device, 111...housing, 112...medium supply section, 113...image forming section, 114...medium discharge section, 115...conveying device, 116...control section, 117...support section, 118...conveying belt, 119...support plate, 120...belt roller, 121...pair of guide plates, 122...conveying roller, 130...head unit, 132...ink tank, 133...circulation flow path, 134...supply pump, 135...negative pressure control device, 211...piezoelectric layer, 221...internal electrode, 222...internal electrode, 223...external electrode, 224...external electrode, 1161...control circuit.

Claims

1. A vibration plate disposed opposite the pressure chamber; an actuator unit having a laminated piezoelectric body, at least a portion of which is disposed opposite the vibration plate and in which a plurality of piezoelectric layers and a plurality of electrodes are laminated; In the actuator section, when viewed from a normal direction of a surface where the pressure chamber and the vibration plate are in contact, at least a part of the outer periphery of an electrode laminated section in which a plurality of electrodes are laminated overlaps with an outer periphery of a pressure region in which the pressure chamber faces the vibration plate, or at least a part of the outer periphery of the electrode laminated section protrudes outside the pressure region, A liquid ejection head, wherein a cross section of the actuator section perpendicular to the normal direction falls within the pressure region within a thickness range equal to the thickness of the vibration plate from the end of the actuator section on the vibration plate side.

2. 2. The liquid ejection head according to claim 1, wherein the laminated piezoelectric element of the actuator section has a chamfered portion at an end on the vibration plate side, the chamfered portion having a reduced cross-sectional area.

3. The liquid ejection head according to claim 1 , wherein the actuator portion includes a spacer portion disposed between the laminated piezoelectric body and the vibration plate.

4. the laminated piezoelectric body of the actuator section has an electrode facing portion where a plurality of electrodes of different polarities face each other, and an electrode non-facing portion where electrodes of different polarities do not face each other, 2. A liquid ejection head as described in claim 1, wherein, when viewed from a normal direction of a contact surface where the pressure chamber and the vibration plate are in contact, at least a portion or all of the non-electrode facing portion of the actuator portion is provided outside an opposing area where the actuator portion and the vibration plate face each other.

5. A vibration plate disposed opposite the pressure chamber; an actuator unit having a laminated piezoelectric body, at least a portion of which is disposed opposite the vibration plate and in which a plurality of piezoelectric layers and a plurality of electrodes are laminated; In the actuator section, when viewed from the normal direction of the surface where the pressure chamber and the vibration plate are in contact, at least a part of the outer periphery of an electrode laminated section in which a plurality of electrodes are laminated overlaps with the outer periphery of a pressure region in which the pressure chamber faces the vibration plate, or at least a part of the outer periphery of the electrode laminated section protrudes outside the pressure region, A liquid ejection head wherein the actuator section has a cross section perpendicular to the normal direction that is within the pressure area within a thickness range that is the same as the thickness of the opposing area of ​​the vibration plate from the end of the actuator section on the actuator section side of the outer part of the opposing area of ​​the vibration plate that faces the actuator section.

Images