Ink jet device

Abstract

The invention provides an ink jet device capable of alleviating concentration of stress applied to a diaphragm. An ink jet device is provided with: a pressure chamber in which ink is stored; a piezoelectric element separated from the pressure chamber in a first direction; and a diaphragm disposed between the pressure chamber and the piezoelectric element in the first direction, the diaphragm having a pressure receiving portion including a top portion and a base portion, the top portion being in contact with the piezoelectric element, the base portion being connected to a main body of the diaphragm, and the base portion being in contact with the piezoelectric element. A width of the base portion is larger than a width of the top portion in a second direction, which is at least one direction perpendicular to the first direction.

Description

Technical Field

[0001] This invention relates to inkjet devices. Background Technology

[0002] In recent years, printed electronic products that form electronic devices through on-demand inkjet printing have become increasingly popular.

[0003] In the fabrication of electronic devices, it is necessary to liquefy various materials into inks. We are actively developing inkjet printheads with piezoelectric drive that can stably eject a wide variety of inks.

[0004] For example, in the inkjet device described in Patent Document 1, a piezoelectric element (PZT: lead zirconate titanate) that is deformed by the application of voltage deforms the diaphragm and presses the pressure chamber to eject ink.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-232290 Summary of the Invention

[0008] In the inkjet device described in Patent Document 1, when the diaphragm deforms, there is a risk that stress will concentrate on the protrusions provided on the diaphragm, causing damage to the diaphragm.

[0009] Non-limiting embodiments of the present invention help to provide an inkjet device capable of mitigating concentrated stress applied to the diaphragm.

[0010] An inkjet apparatus according to an embodiment of the present invention includes: a pressure chamber for storing ink; a piezoelectric element separated from the pressure chamber in a first direction; and a diaphragm disposed between the pressure chamber and the piezoelectric element in the first direction, the diaphragm having a pressure-receiving portion including a top and a base, the top contacting the piezoelectric element, the base being connected to a body of the diaphragm, and the width of the base being greater than the width of the top in a second direction that is at least one direction perpendicular to the first direction.

[0011] An inkjet apparatus according to an embodiment of the present invention includes: a pressure chamber for storing ink; a piezoelectric element separated from the pressure chamber in a first direction; and a diaphragm disposed between the pressure chamber and the piezoelectric element in the first direction, the piezoelectric element having a central region in a second direction as at least one direction perpendicular to the first direction and an end region adjacent to the central region in the second direction, the central region receiving a voltage applied to the piezoelectric element, and the end region not receiving a voltage applied to the piezoelectric element.

[0012] An inkjet apparatus according to an embodiment of the present invention includes: a pressure chamber for storing ink; a piezoelectric element separated from the pressure chamber in a first direction; and a diaphragm disposed between the pressure chamber and the piezoelectric element in the first direction, the diaphragm having a pressure-receiving portion having a top that contacts the piezoelectric element, the width of the top being smaller than the width of the piezoelectric element in a second direction that is at least one direction perpendicular to the first direction.

[0013] According to one embodiment of the present invention, an inkjet device is provided that can mitigate the concentration of stress applied to the diaphragm.

[0014] Further advantages and effects of one embodiment of the invention become apparent from the description and drawings. Such advantages and / or effects are provided separately by the features described in several embodiments, the description, and the drawings, but not all of them need to be provided in order to obtain one or more of the same features. Attached Figure Description

[0015] Figure 1 This is a top view of the inkjet apparatus of the first embodiment.

[0016] Figure 2 This is an exploded perspective view showing the appearance of the inkjet head according to the first embodiment.

[0017] Figure 3 This is a diagram showing an example of the structure of the nozzle of the first embodiment.

[0018] Figure 4 This is a diagram showing an example of the XZ cross-section of the nozzle of the first embodiment.

[0019] Figure 5 This is a diagram showing an example of the YZ cross-section of the nozzle of the first embodiment.

[0020] Figure 6 The pressure-bearing part of the first embodiment Figure 4 Enlarged view of part A in the image.

[0021] Figure 7 This diagram shows an example of the structure of a conventional pressure-bearing section.

[0022] Figure 8 This is a diagram showing an example of the structure of the compression portion of the first modified example.

[0023] Figure 9 This is a diagram showing an example of the structure of the pressure section in the second modified example.

[0024] Figure 10 This is a diagram showing an example of the structure of the compression portion in the third modified example.

[0025] Figure 11 This is a diagram showing an example of the structure of the compression portion in the fourth modified example.

[0026] Figure 12 The pressure-bearing part of the second embodiment Figure 4 Enlarged view of part B in the image.

[0027] Figure 13 This is a schematic diagram illustrating an example of the degree of deformation of the piezoelectric element in the second embodiment.

[0028] Figure 14 This is a diagram showing an example of the chamfered portion of the piezoelectric element according to the second embodiment.

[0029] Figure 15 This is a diagram showing an example of the chamfered portion of the piezoelectric element according to the second embodiment.

[0030] Figure 16 This is a diagram showing the pressure-bearing part and the piezoelectric element of the third embodiment.

[0031] Figure 17 This is a diagram showing the pressure-bearing part and the piezoelectric element of the third embodiment.

[0032] Figure 18 This is a diagram showing the pressure-bearing part and the piezoelectric element of the third embodiment.

[0033] Figure 19 This diagram shows the conventional pressure-bearing part and piezoelectric element.

[0034] Explanation of reference numerals in the attached figures

[0035] 1. Inkjet unit

[0036] 2 abutment

[0037] 3. Guide

[0038] 4. Transfer Platform

[0039] 5 racks

[0040] 6-line header

[0041] 7. Printed objects

[0042] 8 Drive Unit

[0043] 20 nozzles

[0044] 21 Nozzle Plate

[0045] 22 Manifold board

[0046] 23. Diaphragm

[0047] 24. Shell

[0048] 25 Pressure Variation Section

[0049] 30 Pressure-bearing section

[0050] 30a Top

[0051] 30b base

[0052] 31 Ink supply path

[0053] 32 Ink discharge path

[0054] 33 Pressure Chamber

[0055] 34 nozzles

[0056] 35 Next door

[0057] 36 Ink Inlet Flow Path

[0058] 37 Ink outlet flow path

[0059] 38a First piezoelectric element

[0060] 38b Second piezoelectric element

[0061] 39 Base

[0062] 41a Common electrode

[0063] 41b Individual Electrode

[0064] 42a Direction control circuit

[0065] 42b drive circuit

[0066] 51a First Wiring

[0067] 51b Second Wiring

[0068] 56. Movable parts

[0069] 57a First end

[0070] 57b Second end

[0071] 58a First chamfer

[0072] 58b Second chamfer. Detailed Implementation

[0073] Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the accompanying drawings. However, sometimes the necessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of substantially the same structures are sometimes omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0074] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the invention, and are not intended to limit the subject matter described therein.

[0075] <First Implementation>

[0076] Reference Figure 1 The inkjet device 1 will be described. Figure 1 This is a top view of the inkjet device 1 according to the first embodiment. (See diagram below.) Figure 1 As shown, the short side direction of the inkjet device 1 is set as the X direction, the long side direction is set as the Y direction, and the direction perpendicular to the X and Y directions is set as the Z direction.

[0077] The inkjet unit 1 includes a base 2, a guide 3, a transport table 4, a portal frame 5 (an example of a support member), a line head 6, and a drive unit 8.

[0078] The base 2 is composed of a cuboid with a planar shape having a longer rectangle in the scanning direction.

[0079] The guide 3 is fixed to the upper surface of the base 2 along the length direction (Y direction), i.e., the scanning direction. As an example, the guide 3 is composed of a cuboid-shaped component with a rectangular cross-section along a direction orthogonal to the scanning direction.

[0080] The transport stage 4 has a rectangular shape, and its lower surface (the face on the -Z side) contacts the guide 3. The transport stage 4 is guided by the guide 3 and transported along the scanning direction of the base 2. The substrate or other printing object 7 is placed on the transport stage 4.

[0081] The platform 5 has a door-shaped design and is fixed to a predetermined position, such as the middle position, of the base 2 in a way that it spans the short side of the base 2 when viewed from above (from the +Z side).

[0082] The line printhead 6 is an example of an ejector head and is supported on the stage 5. The line printhead 6 ejects ink toward the transport stage 4 as the transport stage 4 passes beneath it. The ink is applied to the coating area of ​​the printing object 7 placed on the transport stage 4.

[0083] It should be noted that in this structure, the line header 6 is as follows: Figure 1 The structure shown is configured with two types of line heads 6 respectively arranged on both sides of the frame 5. However, there may be only one line head 6 arranged on the frame 5, or there may be two frames 5 with a total of four line heads 6 arranged on both sides of each frame 5. The number and arrangement of the line heads 6 can also be changed according to the processing that the printing object 7 is to be performed on using the line heads 6.

[0084] In addition, in order to drive the transport stage 4 along the scanning direction, at least one drive unit 8 is arranged in the base 2 along the scanning direction and connected to the transport stage 4, so that the transport stage 4 can be driven to move along the scanning direction.

[0085] exist Figure 1 In this embodiment, as an example of a drive unit 8, two drive units 8 are arranged on the base 2 along the scanning direction near both ends of the inkjet device 1 in the short side direction. Each drive unit 8 may be a linear motor or a ball screw connected to a rotary motor, etc. In this structure, a drive unit 8 using a linear motor is shown as an example.

[0086] Reference Figure 2 The nozzle 20 will be described. Figure 2 This is an exploded perspective view showing the appearance of the nozzle 20 according to the first embodiment. Figure 2 As shown, the length direction of the nozzle 20 is defined as the X direction, the short side direction as the Y direction, and the direction perpendicular to both the X and Y directions as the Z direction.

[0087] like Figure 2 As shown, the nozzle 20 has a nozzle plate 21, a flow path plate 22, a diaphragm 23, a housing 24, and a pressure variation part 25.

[0088] The nozzle plate 21 is arranged with its surface orthogonal to the Z-direction. The nozzle plate 21 is made of, for example, a stainless steel plate formed by etching and stamping. The thickness of the stainless steel plate is, for example, 100 micrometers. A nozzle 34 for ejecting ink is provided through the nozzle plate 21 along the Y-direction.

[0089] The flow path plate 22 is cuboid in shape and is positioned on the +Z side of the nozzle plate 21 with its surface orthogonal to the Z direction. The flow path plate 22 is held between the diaphragm 23 and the nozzle plate 21. The flow path plate 22 is, for example, a stack of stainless steel plates formed by etching and stamping. The thickness of each stainless steel plate is, for example, 10 to 100 micrometers, and the number of layers is, for example, 3 to 10.

[0090] The diaphragm 23 is disposed on the +Z side of the flow path plate 22 with its surface orthogonal to the Z direction. The diaphragm 23 is held between the housing 24 and the flow path plate 22. The diaphragm 23 is, for example, a thin film with a thickness of 5 to 50 micrometers, and is made, for example, by electroplating a nickel alloy.

[0091] The housing 24 has a cuboid shape and is disposed on the +Z side of the diaphragm 23. The thickness of the housing 24 in the Z direction is, for example, 1 cm. The housing 24 is manufactured, for example, by machining an alloy steel such as stainless steel.

[0092] The pressure regulating unit 25 is housed in the housing 24 and pressurizes the ink stored in the pressure chamber 33 to generate pressure fluctuations. The pressure regulating unit 25 may include, for example, a control board on which a control IC is mounted, which individually controls the pressure of the ink. Figure 4 The applied voltage of the first piezoelectric element 38a and the second piezoelectric element 38b shown.

[0093] The nozzle plate 21 and the flow path plate 22, the flow path plate 22 and the diaphragm 23, the diaphragm 23 and the housing 24, and the diaphragm 23 and the pressure regulating part 25 are respectively bonded and fixed with adhesives. For example, an epoxy-based adhesive with thermosetting properties is used as the adhesive. It should be noted that the adhesives used to bond the various components can be the same or different adhesives. For example, a combination of rubber-based adhesives and epoxy-based adhesives can also be used.

[0094] Reference Figure 3 The general structure of the nozzle 20 is described below. Figure 3 This is a diagram showing an example of the structure of the nozzle 20 according to the first embodiment.

[0095] The printhead 20 has an ink supply path 31, an ink discharge path 32, a pressure chamber 33, a nozzle 34, a partition 35, an ink inlet path 36, and an ink outlet path 37.

[0096] The ink supply path 31 and the ink discharge path 32 are arranged along the X direction of the printhead 20. In addition, the ink supply path 31 and the ink discharge path 32 are arranged opposite each other in the Y direction of the printhead 20.

[0097] Pressure chamber 33 is disposed between ink supply flow path 31 and ink discharge flow path 32. Multiple pressure chambers 33 are disposed along the X direction.

[0098] The ink supplied to the ink supply flow path 31 is supplied to the pressure chamber 33 through the ink inlet flow path 36, which is connected to the pressure chamber 33, under the negative pressure generated by the contraction of the first piezoelectric element 38a and the second piezoelectric element 38b from their extended state. A portion of the ink supplied to the pressure chamber 33 is ejected from the nozzle 34 under the pressure exerted by the extension of the first piezoelectric element 38a and the second piezoelectric element 38b on the pressure chamber 33. The remaining ink is discharged into the ink discharge flow path 32 through the ink outlet flow path 37, which is connected to the pressure chamber 33. The ink in the ink discharge flow path 32 is then supplied back to the ink supply flow path 31.

[0099] Nozzle 34 is a through hole provided in nozzle plate 21, and communicates the inside and outside of pressure chamber 33. Nozzle 34 is provided correspondingly to pressure chamber 33. In addition, ink is ejected from nozzle 34 in the -Z direction.

[0100] In addition, the nozzle 34 is positioned in the Y direction on the ink outlet flow path 37 side (+Y side) of the pressure chamber 33. This structure is effective in ensuring smooth ink ejection from the nozzle 34 and ink discharge into the ink outlet flow path 37.

[0101] Multiple partitions 35 are arranged along the X direction. The partitions 35 separate the pressure chambers 33 that store the ink ejected from the nozzles 34.

[0102] Reference Figure 4 The general structure of the nozzle 20 in the XZ section is described. Figure 4 This is a diagram showing an example of the XZ cross-section of the nozzle 20 of the first embodiment (e.g., Figure 3 (A-A sectional view in the diagram).

[0103] The pressure chamber 33 is composed of a nozzle plate 21, a partition wall 35, and a diaphragm 23. The nozzle plate 21 forms the lower (-Z side) wall of the pressure chamber 33. The partition wall 35 forms the left (+X side) and right (-X side) walls of the pressure chamber 33. The diaphragm 23 forms the upper (+Z side) wall of the pressure chamber 33.

[0104] Multiple first piezoelectric elements 38a and second piezoelectric elements 38b are alternately arranged along the X direction. The first piezoelectric element 38a is disposed on the portion of the diaphragm 23 corresponding to the pressure chamber 33. The first piezoelectric element 38a presses the portion of the diaphragm 23 corresponding to the pressure chamber 33.

[0105] The second piezoelectric element 38b is disposed on the portion of the diaphragm 23 corresponding to the partition wall 35. The second piezoelectric element 38b supports the portion of the diaphragm 23 corresponding to the partition wall 35.

[0106] The base 39 has a plurality of first piezoelectric elements 38a and second piezoelectric elements 38b fixed along the X direction on the side opposite to the diaphragm 23. For example, the base 39 has the same composition as the first piezoelectric elements 38a and second piezoelectric elements 38b, and is integrally formed with the first piezoelectric elements 38a and second piezoelectric elements 38b.

[0107] The diaphragm 23 has a pressure-receiving portion 30 that withstands pressure from the first piezoelectric element 38a and the second piezoelectric element 38b. The pressure-receiving portion 30 protrudes from the main body of the diaphragm 23 and contacts the first piezoelectric element 38a and the second piezoelectric element 38b. The pressure-receiving portion 30 may also be referred to as a protrusion, a projection, or a bulge.

[0108] The center S in the X direction of the pressure-receiving portion 30 is preferably aligned with the center in the X direction of the first piezoelectric element 38a and the second piezoelectric element 38b. Furthermore, the distance between the centers of adjacent pressure-receiving portions 30 in the X direction is preferably the same as the distance between the centers of adjacent first piezoelectric elements 38a and second piezoelectric elements 38b.

[0109] A common electrode 41a is provided on the first piezoelectric element 38a and the second piezoelectric element 38b. The common electrode 41a is electrically connected to the direction control circuit 42a. An individual electrode 41b is provided on the first piezoelectric element 38a and the second piezoelectric element 38b. The individual electrode 41b is electrically connected to the drive circuit 42b.

[0110] Reference Figure 5 The general structure of the nozzle 20 in the YZ section is described. Figure 5 This is a diagram showing an example of the YZ cross-section of the nozzle of the first embodiment (e.g., Figure 3 (B-B sectional view in the diagram).

[0111] like Figure 5 As shown, an ink supply path 31 and an ink discharge path 32 are provided on the first piezoelectric element 38a side (+Z side) of the diaphragm 23.

[0112] An ink inlet flow path 36 and an ink outlet flow path 37 are provided on the pressure chamber 33 side (-Z side) of the diaphragm 23.

[0113] The ink supply flow path 31 and the ink inlet flow path 36 are connected through a hole 31a provided in the diaphragm 23. The ink supplied to the ink supply flow path 31 passes through the hole 31a and the ink inlet flow path 36, and is supplied to the pressure chamber 33.

[0114] The ink discharge path 32 and the ink outlet path 37 are connected through a hole 32a provided in the diaphragm 23. The ink discharged from the pressure chamber 33 to the ink outlet path 37 passes through the hole 32a and then through the ink discharge path 32, and is discharged from the nozzle 20.

[0115] Reference Figure 6 The contact portion where the pressure-bearing part 30 contacts the first piezoelectric element 38a will be described. Figure 6 It is the pressure-bearing part 30 of the first embodiment. Figure 4 Enlarged view of part A in the image.

[0116] The pressure-bearing part 30 has a top 30a, a base 30b, a first part 30c, and a second part 30d.

[0117] The top 30a contacts the first piezoelectric element 38a and is the upper surface (+Z side) of the pressure-receiving portion 30 protruding from the main body of the diaphragm 23. The width L3 in the X direction of the first piezoelectric element 38a is larger than the width L1 in the X direction of the top 30a (L3 > L1).

[0118] It should be noted that the width of the first piezoelectric element 38a may also be larger than the width of the top 30a in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the first piezoelectric element 38a is larger than the width of the top 30a.

[0119] When the first piezoelectric element 38a deforms due to the application of voltage, the top 30a is pressed in the -Z direction by the first piezoelectric element 38a, and the diaphragm 23 deforms. The deformed diaphragm 23 presses the pressure chamber 33 in the -Z direction. That is, the first piezoelectric element 38a presses the pressure chamber 33 in the -Z direction through the diaphragm 23. As a result, the pressure chamber 33 is pressed in the -Z direction, and the ink stored in the pressure chamber 33 is ejected from the nozzle 34 in the -Z direction.

[0120] Furthermore, since the width L3 in the X direction of the first piezoelectric element 38a is larger than the width L1 in the X direction of the top 30a (L3 > L1), stress is uniformly applied to the top 30a as a whole when the first piezoelectric element 38a deforms. As a result, the deformation of the diaphragm 23 is stable, and therefore the pressure change in the pressure chamber 33 is stable. Consequently, the ink ejection from the inkjet device 1 is stable.

[0121] The base 30b corresponds to the part that connects the pressure-bearing part 30 to the main body of the diaphragm 23.

[0122] The pressure-receiving portion 30 has: a first portion 30c, the width of which gradually increases from the width of the top portion 30a to the width of the base portion 30b; and a second portion 30d, the width of the pressure-receiving portion 30 being the same as the width of the top portion 30a on the side closer to the first piezoelectric element 38a than the first portion 30c. That is, the pressure-receiving portion 30 has a stepped portion between the top portion 30a and the base portion 30b, and has a tapered inclined surface that extends outward from the stepped portion to the base portion 30b.

[0123] Furthermore, in the X direction, the width L1 of the top 30a in the X direction is smaller than the width L2 of the base 30b in the X direction (L1 < L2).

[0124] It should be noted that the width of the top 30a may also be smaller than the width of the base 30b in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 30a is smaller than the width of the base 30b.

[0125] Furthermore, when the length of the top 30a and the base 30b of the pressure-bearing portion 30 in the Z direction is set to H, the height C of the first portion 30c in the Z direction is preferably 0.01H or more and H or less.

[0126] Reference Figure 7 A comparison will be made between the conventional pressure-bearing part 300 and the pressure-bearing part 30 of the first embodiment. Figure 7 This is a diagram showing an example of the structure of a conventional pressure-bearing section 300.

[0127] Unlike the pressure-bearing portion 30 of the first embodiment, in the pressure-bearing portion 300, there is no tapered inclined surface between the top 300a and the base 300b, and the surface of the main body of the diaphragm 23 intersects the side surface of the pressure-bearing portion 300 at a right angle. That is, the width L101 of the top 30a in the X direction is equal to the width L102 of the base 300b in the X direction (L101=L102).

[0128] When the diaphragm 23, which has a conventional pressure-bearing portion 300, deforms, stress tends to concentrate at locations A and B compared to the first embodiment. This may reduce the diaphragm 23's resistance to deterioration and damage caused by deformation. Furthermore, the ink ejection from the inkjet device 1 becomes unstable, potentially leading to a decrease in print quality.

[0129] In the first embodiment, the pressure-bearing portion 30 has a tapered inclined surface on its side, thus alleviating stress concentration at portions A and B of the diaphragm 23. As a result, the diaphragm 23 is more resistant to deterioration and damage caused by deformation.

[0130] (First variation)

[0131] Reference Figure 8 The pressure-bearing part 301 of the first modified example will be described. Figure 8 This is a diagram showing an example of the structure of the pressure-bearing part 301 in the first modified example.

[0132] The pressure-bearing portion 301 has a top 301a, a base 301b, and a first portion 301c. The top 301a and the base 301b are the same as the top 30a and the base 30b in the first embodiment.

[0133] The pressure-bearing portion 301 in the first modified example differs from the pressure-bearing portion 30 in the first embodiment. It does not have a stepped portion between the top 301a and the base 301b, and has a first portion 301c whose width gradually increases from the width of the top 301a to the width of the base 301b. The width of the first portion 301c increases linearly from the base 301b.

[0134] That is, the pressure-bearing portion 301 has a tapered inclined surface that extends outward from the top 301a to the base 301b. As a result, the width L111 in the X direction of the top 301a is shorter than the width L112 in the X direction of the base 301b (L111 < L112).

[0135] It should be noted that the width of the top 301a may also be smaller than the width of the base 301b in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 301a is smaller than the width of the base 301b.

[0136] In the first variation, similar to the first embodiment, the pressure-bearing portion 301 has a structure that alleviates stress concentration in portions A and B when pressed by the first piezoelectric element 38a, thus achieving the same effect as the first embodiment in the first variation.

[0137] (Second variation)

[0138] Reference Figure 9 The pressure-bearing part 302 of the second modified example will be described. Figure 9 This is a diagram showing an example of the structure of the pressure-bearing part 302 in the second modified example.

[0139] The pressure-bearing portion 302 has a top 302a, a base 302b, a first portion 302c, and a second portion 302d. The top 302a and the base 302b are the same as the top 30a and the base 30b in the first embodiment.

[0140] The pressure-receiving portion 302 in the second modification example has the same features as the pressure-receiving portion 30 in the first embodiment: a first portion 302c, the width of which gradually increases from the width of the top portion 302a to the width of the base portion 302b; and a second portion 302d, the width of the pressure-receiving portion 302 being the same as the width of the top portion 302a on the side closer to the first piezoelectric element 38a than the first portion 302c. The width of the first portion 302c increases curvilinearly towards the base portion 302b.

[0141] That is, the pressure-bearing portion 302 has a curved surface that extends outward from the top 302a to the base 302b. Therefore, the width L121 of the top 302a in the X direction is smaller than the width L122 of the base 302b in the X direction (L121 < L122).

[0142] It should be noted that the width of the top 302a may also be smaller than the width of the base 302b in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 302a is smaller than the width of the base 302b.

[0143] Additionally, on the side of the second 302d Figure 9 When the outline of the cross-section shown is an arc, the radius of curvature of the arc is preferably 0.01H or more and H or less. It should be noted that when the radius of curvature of the arc is H, the first part 302c does not exist.

[0144] In the second variation, similar to the first embodiment, the pressure-bearing portion 302 has a structure that alleviates stress concentration in portions A and B when pressed by the first piezoelectric element 38a, thus achieving the same effect as the first embodiment in the second variation.

[0145] (Third variation)

[0146] Reference Figure 10 The pressure-bearing part 303 of the third modified example will be described. Figure 10 This is a diagram showing an example of the structure of the pressure-bearing part 303 in the third modified example.

[0147] In the third modification, the pressure-bearing portion 303 has a membrane 303e on the side of the first piezoelectric element 38a of the diaphragm 23. Furthermore, the diaphragm 23 has membranes 303f of uniform thickness on both sides of the membrane 303e. The membranes 303e and 303f function as protective membranes for the diaphragm 23.

[0148] The pressure-bearing portion 303 has a top 303a, a base 303b, a first portion 303c, and a second portion 303d. The top 303a is the same as the top 30a in the first embodiment. The base 303b corresponds to the portion where the membrane 303e and the main body of the pressure-bearing portion 303 are connected to the main body of the diaphragm 23.

[0149] The membrane 303e of the pressure-bearing portion 303, like in the second modified example, has: a first portion 303c, the width of which gradually increases from the width of the top 303a to the width of the base 303b; and a second portion 303d, which makes the width of the pressure-bearing portion 303 the same as the width of the top 303a on the side closer to the first piezoelectric element 38a than the first portion 303c. The width of the first portion 303c increases curvilinearly towards the base 303b.

[0150] The pressure-bearing portion 303 has a curved surface that extends outward from the top 303a to the base 303b. Therefore, the width L131 of the top 303a in the X direction is smaller than the width L132 of the base 303b in the X direction (L131 < L132).

[0151] It should be noted that the width of the top 303a may also be smaller than the width of the base 303b in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 303a is smaller than the width of the base 303b.

[0152] Membranes 303e, for example, are made using inorganic and organic materials and through chemical vapor deposition (CVD), physical vapor deposition (PVD), and other methods.

[0153] For example, membrane 303e uses inorganic materials such as SiO2 (silicon dioxide), Al2O3 (alumina), and TiO2 (titanium oxide), and organic materials such as parylene. Furthermore, the membrane thickness of membrane 303e is preferably 0.05 micrometers or more and 5 micrometers or less.

[0154] Additionally, on the side of the second 302d Figure 10 When the outline of the cross-section shown is an arc, the radius of curvature of the arc is preferably 0.01H or more and H or less. It should be noted that when the radius of curvature of the arc is H, the first part 303c does not exist.

[0155] In the third variation, similar to the first embodiment, the pressure-bearing part 303 can alleviate the stress concentration at parts A and B when pressed by the first piezoelectric element 38a.

[0156] In the third variation, similar to the first embodiment, the pressure-bearing portion 303 has a structure that alleviates stress concentration in portions A and B when pressed by the first piezoelectric element 38a, thus achieving the same effect as the first embodiment in the third variation.

[0157] (Fourth variation)

[0158] Reference Figure 11 The compression portion 304 of the fourth modified example will be described. Figure 11 This is a diagram showing an example of the structure of the pressure-bearing part 304 in the fourth modified example.

[0159] In the fourth modification, the pressure-receiving part 304 has membranes 304e and 304f on the side of the first piezoelectric element 38a of the diaphragm 23, and a membrane 304g on the side of the pressure chamber 33 of the diaphragm 23. Membranes 304e and 304f are the same membranes as in the third modification, and function as protective membranes for protecting the diaphragm 23.

[0160] The membrane 304e of the pressure-bearing portion 304, like in the third modified example, has: a first portion 304c, whose width gradually increases from the width of the top 304a to the width of the base 304b; and a second portion 304d, which makes the width of the pressure-bearing portion 304 the same as the width of the top 304a on the side closer to the first piezoelectric element 38a than the first portion 304c. The width of the first portion 304c increases curvilinearly towards the base 304b.

[0161] The membrane 304e of the pressure-bearing portion 304, like the second modified example, has a first portion 304c that widens towards the base 304b and has curved sides, and a second portion 304d that has a constant width towards the base 304b. The width L141 of the top 304a in the X direction is smaller than the width L142 of the base 304b in the X direction (L141 < L142).

[0162] It should be noted that the width of the top 304a may also be smaller than the width of the base 304b in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 304a is smaller than the width of the base 304b.

[0163] In addition, membranes 304e, 304f, and 304g are fabricated using inorganic and organic materials and by means of CVD and PVD, similar to the third modified example.

[0164] In the fourth variation, similar to the first embodiment, the pressure-bearing portion 304 has a structure that alleviates stress concentration in portions A and B when pressed by the first piezoelectric element 38a, thus achieving the same effect as the first embodiment in the fourth variation.

[0165] <Second Implementation>

[0166] Reference Figure 12 The second piezoelectric element 38b, which is disposed on the upper part of the partition 35, will be described. Figure 12 yes Figure 4 Enlarged view of part B in the figure. In the second embodiment, the structure of the second piezoelectric element 38b, which supports the partition wall 35 through the diaphragm 23, is different from that in the first embodiment.

[0167] The second piezoelectric element 38b has a common electrode 41a and a separate electrode 41b. The first wiring 51a is electrically connected to the common electrode 41a (first electrode), and the second wiring 51b is electrically connected to the separate electrode 41b (second electrode).

[0168] A common electrode 41a applies a voltage Va to the second piezoelectric element 38b via a first wiring 51a, and a separate electrode 41b applies a voltage Vb, lower than the voltage Va, to the second piezoelectric element 38b via the second wiring 51b. For example, the voltage Va could be +V1 volts and the voltage Vb could be -V1 volts. The first wiring 51a and the second wiring 51b are connected to electrodes of opposite polarity.

[0169] In addition, the second piezoelectric element 38b has a movable part 56, a first end 57a, and a second end 57b.

[0170] The movable part 56 is located near the center of the second piezoelectric element 38b and includes a first wiring 51a electrically connected to the common electrode 41a and a second wiring 51b electrically connected to the individual electrode 41b. Within the movable part 56, the first wiring 51a and the second wiring 51b are alternately arranged along the Z direction.

[0171] Therefore, when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, polarization occurs in the movable part 56 due to the potential difference generated between the first wiring 51a and the second wiring 51b. This polarization causes the movable part 56 to deform. That is, if voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, the movable part 56 of the second piezoelectric element 38b deforms.

[0172] The first end portion 57a ​​is the end portion on the common electrode 41a side of the second piezoelectric element 38b, and includes a first wiring 51a electrically connected to the common electrode 41a. The first end portion 57a ​​does not include a second wiring 51b electrically connected to the individual electrode 41b. Therefore, when voltage Va and voltage Vb are applied to the common electrode 41a and the individual electrode 41b, polarization does not occur in the first end portion 57a. Thus, although the first end portion 57a ​​is somewhat affected by the deformation of the movable part 56, it does not deform significantly.

[0173] The second end 57b is the end portion on the individual electrode 41b side of the second piezoelectric element 38b, and includes a second wiring 51b electrically connected to the individual electrode 41b. The second end 57b does not include the first wiring 51a electrically connected to the common electrode 41a. Therefore, when voltage Va and voltage Vb are applied to the common electrode 41a and the individual electrode 41b, polarization does not occur in the second end 57b. Thus, although the second end 57b is somewhat affected by the deformation of the movable part 56, it will not deform significantly.

[0174] The end regions (first end 57a and second end 57b) of the second piezoelectric element 38b are regions that are difficult to deform when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b.

[0175] Additionally, the second piezoelectric element 38b has end regions (first end 57a and second end 57b) in the X direction. It should be noted that the second piezoelectric element 38b may also have a non-driven end region in another direction in the XY plane. In other words, the second piezoelectric element 38b has a non-driven end region in at least one direction perpendicular to the Z direction of the pressing diaphragm 23.

[0176] The second piezoelectric element 38b has a central region (movable portion 56) in the X direction and end regions (first end 57a and second end 57b) adjacent to the central region (movable portion 56) in the X direction. The central region (movable portion 56) includes both a first wiring 51a and a second wiring 51b. The central region (movable portion 56) receives voltage applied between the common electrode 41a and the individual electrode 41b of the second piezoelectric element 38b via the first wiring 51a and the second wiring 51b. On the other hand, the end regions (first end 57a and second end 57b) include only one of the first wiring 51a and the second wiring 51b. Since the end regions (first end 57a and second end 57b) include only one of the wiring 51a and the second wiring 51b, they do not receive voltage applied between the common electrode 41a and the individual electrode 41b of the second piezoelectric element 38b.

[0177] In addition, the first end 57a and the second end 57b have a stepped first chamfer 58a and a second chamfer 58b at the corners on the diaphragm 23 side of the first end 57a and the second end 57b.

[0178] The corners of the diaphragm 23 are stepped, so the first end 57a and the second end 57b are difficult to deform, which can alleviate the stress concentration at parts A and B.

[0179] Reference Figure 13 The deformation of the second piezoelectric element 38b when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b will be described in further detail. Figure 13 This is a schematic diagram illustrating an example of the degree of deformation of the piezoelectric element in the second embodiment.

[0180] exist Figure 13 In the diagram, the length of the arrow indicates the magnitude d of the deformation of the second piezoelectric element 38b. The larger the magnitude d of the deformation of the second piezoelectric element 38b, the longer the arrow. Furthermore, the deformation of the second piezoelectric element 38b in the -Z direction is set to positive.

[0181] In the movable portion 56 of the second piezoelectric element 38b, the magnitude of the deformation d of the second piezoelectric element 38b decreases from near the center to the end region. Near the center of the movable portion 56, the magnitude of the deformation d of the second piezoelectric element 38b becomes the largest, and this maximum value is set as dmax.

[0182] On the other hand, the end region of the second piezoelectric element 38b functions as a fixed end because it is difficult to deform.

[0183] By setting the distribution of the deformation magnitude to this distribution, it is possible to mitigate... Figure 13The stress concentration at locations A and B is shown. Furthermore, the first end 57a and the second end 57b have a first chamfer 58a and a second chamfer 58b, which makes the first end 57a and the second end 57b even less deformable and can further alleviate the stress concentration at locations A and B.

[0184] It should be noted that when the width of the movable part 56 in the X direction is set to W1, W1 is preferably 500 micrometers or more and 2000 micrometers or less.

[0185] When the width of the first end 57a and the second end 57b in the X direction is set to W2, W2 is preferably 100 micrometers or more and 200 micrometers or less.

[0186] When the chamfer width in the X direction of the first chamfer portion 58a and the second chamfer portion 58b is set to W3, W3 is preferably 20 micrometers or more and 100 micrometers or less.

[0187] When the chamfer height in the Z direction of the first chamfered portion 58a and the second chamfered portion 58b is set to H3, H3 is preferably 20 micrometers or more and 200 micrometers or less.

[0188] The maximum value of the deformation d of the second piezoelectric element 38b, dmax, is preferably 0.2 micrometers or more and 2 micrometers or less.

[0189] In addition, W2 / dmax is preferably 100 or more and 1000 or less, and W2 / W3 is preferably 1 or more and 10 or less.

[0190] It should be noted that, as Figure 14 As shown, the first end 57a and the second end 57b may also have a straight first chamfered portion 581a and a second chamfered portion 581b at the corners on the diaphragm 23 side of the first end 57a and the second end 57b.

[0191] In addition, such as Figure 15 As shown, the first end 57a and the second end 57b may also have a rounded first chamfer 582a and a second chamfer 582b at the corners on the diaphragm 23 side of the first end 57a and the second end 57b.

[0192] Even with this shape at the corner, the first end 57a and the second end 57b are difficult to deform, thus mitigating stress concentration at parts A and B.

[0193] It should be noted that in the second embodiment, the second piezoelectric element 38b has a non-driven first end 57a and a second end 57b, but Figure 4The first piezoelectric element 38a shown may also have regions corresponding to the first end 57a and the second end 57b.

[0194] <Third Implementation Method>

[0195] Reference Figures 16 to 19 The contact between the pressure-bearing part 30 and the first piezoelectric element 38a will be described. Figures 16 to 18 This is a diagram showing the pressure-receiving part 30 and the first piezoelectric element 38a in the third embodiment.

[0196] The structure of the pressure-receiving part 30 and the first piezoelectric element 38a in the third embodiment is the same as that in the first embodiment, so the description of the structure of the pressure-receiving part 30 and the first piezoelectric element 38a is omitted.

[0197] In the third embodiment, it is the same as in the first embodiment (for example, refer to...). Figure 6 The first piezoelectric element 38a contacts the top 30a of the pressure-receiving part 30.

[0198] It should be noted that the width of the top 30a may also be smaller than the width of the first piezoelectric element 38a in the X direction in another direction on the XY plane. In other words, in at least one direction perpendicular to the Z direction of the first piezoelectric element 38a pressing the diaphragm 23, the width of the top 30a is smaller than the width of the first piezoelectric element 38a.

[0199] For example, when the difference between L3 and L1 is set as the difference d (d = L3 - L1), the difference d is preferably 1 micrometer or more and 100 micrometers or less.

[0200] For example, due to manufacturing deviations in inkjet unit 1, it is possible that... Figure 17 As shown, the first piezoelectric element 38a is offset to the left relative to the top 30a. Alternatively, for example, it may also be as follows: Figure 18 As shown, the first piezoelectric element 38a is offset to the right relative to the top 30a.

[0201] exist Figures 16 to 18 In any of the cases, since the contact area between the top 30a and the first piezoelectric element 38a remains unchanged, the stress applied to the top 30a by the first piezoelectric element 38a also remains unchanged. Therefore, the deformation of the diaphragm 23 is stable, and the pressure change in the pressure chamber 33 is stable. Therefore, the ink ejection of the inkjet device 1 is stable.

[0202] For example, such as Figure 19 As shown, when the first piezoelectric element 38a is significantly offset relative to the top 30a due to manufacturing deviations in the inkjet device 1, the area ratio of the contact portion P where the top 30a contacts the first piezoelectric element 38a is... Figures 16 to 18The situation is small. In addition, the width Pa of the contact part P in the X direction becomes smaller than the width La (Pa = L1 - La).

[0203] Since the force applied by the first piezoelectric element 38a is constant, the stress applied to the diaphragm 23 becomes uneven when the area of ​​the contact portion P changes. As a result, the degree of stress concentration in portions A and B increases.

[0204] In the third embodiment, even when the first piezoelectric element 38a is offset to some extent relative to the top 30a, since the width L1 of the top 30a in the X direction is smaller than the width L3 of the first piezoelectric element 38a in the X direction (L1 < L3), the inkjet device 1 has a structure that can maintain the area of ​​the contact portion P. Therefore, the inkjet device 1 achieves the effect of mitigating the stress concentration at portions A and B of the diaphragm 23.

[0205] <Summary of Implementation Methods>

[0206] As described above, the inkjet apparatus of this embodiment includes: a partition that separates a pressure chamber for storing ink ejected from a nozzle; a piezoelectric element that presses the pressure chamber through a diaphragm; and a diaphragm that, when pressed by the piezoelectric element, applies pressure to the pressure chamber communicating with the nozzle from which the ink is ejected, the diaphragm having a pressure-receiving portion whose top contacts the piezoelectric element and whose base is connected to the main body of the diaphragm, wherein the width of the base is greater than the width of the top in at least one direction perpendicular to the direction in which the piezoelectric element presses the diaphragm.

[0207] According to this structure, when the first piezoelectric element 38a and the second piezoelectric element 38b, which are subjected to voltage, deform the diaphragm 23, the stress concentration at parts A and B of the diaphragm 23 is mitigated.

[0208] In the above embodiments, the term "...part" used for each constituent element can also be replaced by other terms such as "...component", "...device", "...unit" or "...module".

[0209] The embodiments have been described above with reference to the accompanying drawings, but the present invention is not limited to this example. Those skilled in the art will be able to conceive of various modifications or alterations within the scope of the patented technical solution. It should be understood that such modifications or alterations also fall within the technical scope of the present invention. Furthermore, the constituent elements in the embodiments can be arbitrarily combined without departing from the spirit of the present invention.

[0210] Industrial applicability

[0211] This invention is useful as an inkjet device.

Claims

1. An inkjet device, wherein the inkjet device comprises: a pressure chamber that stores ink; a piezoelectric element that is separated from the pressure chamber in a first direction; and a diaphragm that is disposed between the pressure chamber and the piezoelectric element in the first direction, the diaphragm has a pressure receiving portion that includes a top portion and a base portion, the top portion is in contact with the piezoelectric element, the base portion is connected to a main body of the diaphragm, a width of the base portion is larger than a width of the top portion in a second direction that is at least one direction perpendicular to the first direction.

2. The inkjet device according to claim 1, wherein the pressure receiving portion has at least a first portion having a width that gradually increases from the width of the top portion to the width of the base portion.

3. The inkjet device according to claim 2, wherein the pressure receiving portion further has a second portion between the first portion and the piezoelectric element, the second portion having a width that is the same as the width of the top portion.

4. The inkjet device according to claim 2, wherein the width of the first portion of the pressure receiving portion increases linearly.

5. The inkjet device according to claim 2, wherein the width of the first portion of the pressure receiving portion increases curvilinearly.

6. The inkjet device according to claim 1, wherein the pressure receiving portion has a first protective film on a first surface facing the piezoelectric element.

7. The inkjet device according to claim 6, wherein the diaphragm has a second protective film on a second surface facing the pressure chamber.

8. The inkjet device according to claim 1, wherein the piezoelectric element has a central region in the second direction and an end region adjacent to the central region in the second direction, the central region receives a voltage applied to the piezoelectric element, the end region does not receive the voltage applied to the piezoelectric element.

9. The inkjet device according to claim 8, wherein one of a first wiring and a second wiring connected to a first electrode and a second electrode, respectively, that are different in polarity from the first electrode is provided in the end region, and both the first wiring and the second wiring are provided in the central region.

10. The inkjet device according to claim 8, wherein the piezoelectric element has a chamfered portion at a corner on the diaphragm side of the end region.

11. The inkjet device according to claim 1, wherein the width of the top portion is smaller than a width of the piezoelectric element in the second direction.

12. An inkjet device, wherein the inkjet device comprises: a pressure chamber that stores ink; a piezoelectric element that is separated from the pressure chamber in a first direction; and a diaphragm that is disposed between the pressure chamber and the piezoelectric element in the first direction, the piezoelectric element has a central region in a second direction that is at least one direction perpendicular to the first direction and an end region adjacent to the central region in the second direction, the central region receives a voltage applied to the piezoelectric element, the end region does not receive the voltage applied to the piezoelectric element.

13. The inkjet device according to claim 12, wherein The piezoelectric element also has a central region adjacent to the end region, One of a first wiring and a second wiring connected to the first electrode and a second electrode different in polarity from the first electrode, respectively, is provided in the end region, and both the first wiring and the second wiring are provided in the central region.

14. The inkjet device according to claim 12, wherein The piezoelectric element has a chamfered portion at a corner on the diaphragm side of the end region.

15. An inkjet device, wherein The inkjet device includes: a pressure chamber that stores ink; a piezoelectric element that is separated from the pressure chamber in a first direction; and a diaphragm that is disposed between the pressure chamber and the piezoelectric element in the first direction, the diaphragm has a pressure receiving portion that has a top portion in contact with the piezoelectric element, a width of the top portion in a second direction that is at least one direction perpendicular to the first direction is smaller than a width of the piezoelectric element.

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