Inkjet apparatus

Abstract

To provide an ink jet apparatus capable of relaxing the concentration of stress applied to a diaphragm.SOLUTION: The diaphragm has a pressure-receiving section, the top section of which is in contact with the piezoelectric element and the base section of which is connected to the main body of the diaphragm, and the width of the base section is greater than the width of the top section in at least one direction perpendicular to the direction in which the piezoelectric element presses the diaphragm.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to inkjet devices. [Background technology]

[0002] In recent years, printed electronics, which involves forming electronic devices on demand using inkjet printing, has become increasingly popular.

[0003] The production of electronic devices requires the conversion of a wide variety of materials into inks, and active development is underway to develop piezoelectrically driven inkjet heads that are capable of stably ejecting a wide variety of inks.

[0004] For example, in the inkjet device described in Patent Document 1, a piezoelectric element (PZT: lead zirconate titanate) is deformed when a voltage is applied, which deforms a diaphragm and presses a pressure chamber to eject ink. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-232290 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the inkjet device described in Patent Document 1, when the diaphragm deforms, stress is concentrated on the protrusions provided on the diaphragm, which may damage the diaphragm.

[0007] Non-limiting examples of the present disclosure contribute to providing an inkjet device that can reduce the concentration of stress on a diaphragm. [Means for solving the problem]

[0008] An inkjet device according to one embodiment of the present disclosure comprises a partition wall separating pressure chambers that store ink to be ejected from nozzles, a piezoelectric element that presses the pressure chambers via a diaphragm, and a diaphragm that applies pressure to the pressure chambers that communicate with the nozzles that eject ink when pressed by the piezoelectric element, wherein the diaphragm has a pressure-receiving portion whose top contacts the piezoelectric element and whose base connects to the main body of the diaphragm, and 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.

[0009] An inkjet device according to one embodiment of the present disclosure comprises a partition wall separating pressure chambers that store ink to be ejected from nozzles, a piezoelectric element that presses the pressure chambers via a diaphragm, and a diaphragm that applies pressure to the pressure chambers that communicate with the nozzles that eject ink when pressed by the piezoelectric element, wherein the piezoelectric element has an end region that is not driven in at least one direction perpendicular to the direction in which the piezoelectric element presses the diaphragm.

[0010] An inkjet device according to one embodiment of the present disclosure comprises a partition wall separating pressure chambers that store ink to be ejected from nozzles, a piezoelectric element that presses the pressure chambers via a diaphragm, and a diaphragm that applies pressure to the pressure chambers that communicate with the nozzles that eject ink when pressed by the piezoelectric element, wherein the diaphragm has a pressure-receiving portion whose top contacts the piezoelectric element, and the width of the top is smaller than the width of the piezoelectric element in at least one direction perpendicular to the direction in which the piezoelectric element presses the diaphragm. [Effects of the Invention]

[0011] According to an embodiment of the present disclosure, it is possible to provide an ink jet device capable of reducing the concentration of stress on a diaphragm.

[0012] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of an inkjet device according to a first embodiment; [Figure 2] FIG. 1 is an exploded perspective view showing the appearance of an inkjet head according to a first embodiment; [Figure 3] FIG. 1 is a diagram illustrating an example of the configuration of a discharge head according to a first embodiment. [Figure 4] FIG. 1 is a diagram showing an example of an XZ cross section of a discharge head according to a first embodiment. [Figure 5] FIG. 1 is a diagram showing an example of a YZ cross section of a discharge head according to a first embodiment. [Figure 6] 5 is an enlarged view of a portion A in FIG. 4 of the pressure-receiving portion according to the first embodiment. [Figure 7] FIG. 1 is a diagram showing an example of the configuration of a conventional pressure receiving section. [Figure 8] FIG. 10 is a diagram showing an example of the configuration of a conventional pressure-receiving portion in a first modified example. [Figure 9] FIG. 10 is a diagram showing an example of the configuration of a conventional pressure-receiving portion in a second modified example. [Figure 10] FIG. 10 is a diagram showing an example of the configuration of a conventional pressure-receiving portion in a third modified example. [Figure 11] FIG. 10 is a diagram showing an example of the configuration of a conventional pressure-receiving portion in a fourth modified example. [Figure 12] 5 is an enlarged view of a portion B in FIG. 4 of a pressure receiving portion according to a second embodiment. [Figure 13] 10A and 10B are schematic diagrams illustrating an example of the degree of deformation of a piezoelectric element according to a second embodiment; [Figure 14] FIG. 10 is a diagram showing an example of a chamfered portion of a piezoelectric element according to a second embodiment; [Figure 15] FIG. 10 is a diagram showing an example of a chamfered portion of a piezoelectric element according to a second embodiment; [Figure 16] FIG. 10 is a diagram showing a pressure receiving portion and a piezoelectric element according to a third embodiment. [Figure 17] FIG. 10 is a diagram showing a pressure receiving portion and a piezoelectric element according to a third embodiment. [Figure 18] FIG. 10 is a diagram showing a pressure receiving portion and a piezoelectric element according to a third embodiment. [Figure 19] FIG. 1 shows a conventional pressure receiving portion and piezoelectric element. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0015] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0016] First Embodiment The inkjet device 1 will be described with reference to Fig. 1. Fig. 1 is a plan view of the inkjet device 1 according to the first embodiment. As shown in Fig. 1, the widthwise direction of the inkjet device 1 is the X direction, the lengthwise direction is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction.

[0017] The inkjet device 1 includes a base 2, a guide 3, a conveying table 4, a gate-shaped gantry 5 as an example of a support member, a line head 6, and a drive unit 8.

[0018] The base 2 is configured as a rectangular parallelepiped having a rectangular planar shape that is long in the scanning direction.

[0019] The guide 3 is fixed to the upper surface of the base 2 along the longitudinal direction (Y direction) of the base 2, i.e., along the scanning direction. As an example, the guide 3 is made of a member having a rectangular parallelepiped shape with a rectangular cross section along a direction perpendicular to the scanning direction.

[0020] The conveying table 4 has a rectangular shape, and its lower surface (the surface on the -Z side) contacts the guide 3. The conveying table 4 is guided by the guide 3 and conveyed in the scanning direction of the base 2. A printing object 7 such as a substrate is placed on the conveying table 4.

[0021] The gantry 5 has a gate-like shape and is fixed to a predetermined position, for example, a middle position, of the base 2 so as to straddle the base 2 in the short direction in a plan view (when viewed from the +Z side).

[0022] The line head 6 is an example of an ejection head, and is supported by the gantry 5. The line head 6 ejects ink toward the conveying table 4 in synchronization with the timing at which the conveying table 4 passes under the line head 6. The ink is applied to an application area of ​​a printing target 7 placed on the conveying table 4.

[0023] 1, two types of line heads 6 are arranged on each side of the gantry 5, but only one line head 6 may be arranged on the gantry 5, or two gantries 5 may be arranged with a total of four line heads 6 arranged on each side of each gantry 5. The number and arrangement of the line heads 6 may be changed depending on the processing to be performed by the line heads 6 on the printing object 7.

[0024] In addition, in order to drive the conveying table 4 in the scanning direction, at least one driving unit 8 is arranged on the base 2 along the scanning direction and connected to the conveying table 4, making it possible to drive and convey the conveying table 4 in the scanning direction.

[0025] 1, as an example of the 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 may be a ball screw connected to a rotary motor, etc. In this configuration, a drive unit 8 using a linear motor is shown as an example.

[0026] The discharge head 20 will be described with reference to Fig. 2. Fig. 2 is an exploded perspective view showing the appearance of the discharge head 20 according to the first embodiment. As shown in Fig. 2, the longitudinal direction of the discharge head 20 is the X direction, the lateral direction is the Y direction, and the direction perpendicular to the X direction and Y direction is the Z direction.

[0027] As shown in FIG. 2, the ejection head 20 includes a nozzle plate 21, a flow path plate 22, a diaphragm 23, a housing 24, and a pressure fluctuation unit 25.

[0028] The nozzle plate 21 is disposed so that its plate surface is perpendicular to the Z direction. The nozzle plate 21 is made of a stainless steel plate formed by, for example, etching or press working. The thickness of the stainless steel plate is, for example, 100 micrometers. Nozzles 34 that eject ink are formed in the nozzle plate 21 along the Y direction.

[0029] The flow path plate 22 has a rectangular parallelepiped shape and is disposed on the +Z side of the nozzle plate 21 so that its plate surface is perpendicular to the Z direction. The flow path plate 22 is sandwiched between the diaphragm 23 and the nozzle plate 21. The flow path plate 22 is a laminate of stainless steel plates formed by, for example, etching or press working. The thickness of each stainless steel plate is, for example, 10 to 100 micrometers, and the number of laminated layers is, for example, 3 to 10.

[0030] The diaphragm 23 is disposed on the +Z side of the flow path plate 22 so that its plate surface is perpendicular to the Z direction. The diaphragm 23 is sandwiched between the housing 24 and the flow path plate 22. The diaphragm 23 is, for example, a thin film having a thickness of 5 to 50 micrometers, and is produced by, for example, electroplating a nickel alloy.

[0031] The housing 24 has a rectangular parallelepiped shape and is disposed on the +Z side of the diaphragm 23. The housing 24 has a thickness of 1 centimeter in the Z direction, for example. The housing 24 is produced by cutting an alloy steel such as stainless steel.

[0032] The pressure fluctuation unit 25 is housed in the housing 24, and generates pressure fluctuations by pressurizing the ink stored in the pressure chamber 33. The pressure fluctuation unit 25 has, for example, a control board on which a control IC or the like is mounted, and the control board individually controls the voltages applied to the piezoelectric elements 38a and 38b shown in FIG.

[0033] 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 fluctuation unit 25 are each bonded and fixed with an adhesive. For example, an epoxy adhesive having thermosetting properties is used as the adhesive. The adhesives used to bond the respective components may be the same adhesive or different adhesives. For example, a rubber adhesive and an epoxy adhesive may be used in combination.

[0034] The schematic configuration of the ejection head 20 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the configuration of the ejection head 20 according to the first embodiment.

[0035] The ejection head 20 has an ink supply channel 31 , an ink discharge channel 32 , a pressure chamber 33 , a nozzle 34 , a partition wall 35 , an ink inlet channel 36 , and an ink outlet channel 37 .

[0036] The ink supply flow path 31 and the ink discharge flow path 32 are arranged along the X direction of the ejection head 20. The ink supply flow path 31 and the ink discharge flow path 32 are also arranged to face each other in the Y direction of the ejection head 20.

[0037] The pressure chamber 33 is disposed between the ink supply channel 31 and the ink discharge channel 32. A plurality of pressure chambers 33 are disposed in the X direction.

[0038] The ink supplied to the ink supply flow path 31 is supplied to the pressure chamber 33 via the ink inlet flow path 36 that communicates with the pressure chamber 33 by the negative pressure that is generated in the pressure chamber 33 when the piezoelectric elements 38a and 38b contract from their expanded state. Some of the ink supplied to the pressure chamber 33 is ejected from the nozzle 34 by the pressure applied to the pressure chamber 33 due to the expansion of the piezoelectric elements 38a and 38b, and the remainder is discharged to the ink discharge flow path 32 via the ink outlet flow path 37 that communicates with the pressure chamber 33. The ink in the ink discharge flow path 32 is supplied again to the ink supply flow path 31.

[0039] The nozzles 34 are through holes provided in the nozzle plate 21, and communicate the inside and outside of the pressure chambers 33. The nozzles 34 are provided corresponding to the pressure chambers 33. Furthermore, ink is ejected from the nozzles 34 in the −Z direction.

[0040] Furthermore, in the Y direction, the nozzle 34 is provided on the ink outlet flow path 37 side (+Y side) of the pressure chamber 33. This configuration is effective for smoothly ejecting ink from the nozzle 34 and discharging ink to the ink outlet flow path 37.

[0041] A plurality of partition walls 35 are arranged in the X direction. The partition walls 35 separate the pressure chambers 33 that store the ink ejected from the nozzles 34.

[0042] The schematic configuration of the discharge head 20 in an XZ cross section will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of an XZ cross section of the discharge head 20 according to the first embodiment (for example, a cross section taken along line AA in Fig. 3).

[0043] The pressure chamber 33 is composed of a nozzle plate 21, a partition wall 35, and a diaphragm 23. The nozzle plate 21 constitutes the lower (-Z side) wall of the pressure chamber 33. The partition wall 35 constitutes the left (+X side) and right (-X side) walls of the pressure chamber 33. The diaphragm 23 constitutes the upper (+Z side) wall of the pressure chamber 33.

[0044] A plurality of piezoelectric elements 38a and piezoelectric elements 38b are arranged alternately in the X direction. Piezoelectric element 38a (first piezoelectric element) is arranged in a portion of diaphragm 23 that corresponds to pressure chamber 33. Piezoelectric element 38a presses the portion of diaphragm 23 that corresponds to pressure chamber 33.

[0045] The piezoelectric element 38b (second piezoelectric element) is disposed in a portion of the diaphragm 23 that corresponds to the partition wall 35. The piezoelectric element 38b supports the portion of the diaphragm 23 that corresponds to the partition wall 35.

[0046] The base 39 fixes a plurality of piezoelectric elements 38a and 38b arranged in the X direction on the side opposite to the diaphragm 23. For example, the base 39 has the same composition as the piezoelectric elements 38a and 38b, and is molded integrally with the piezoelectric elements 38a and 38b.

[0047] The diaphragm 23 has a pressure-receiving portion 30 that receives pressure from the piezoelectric elements 38a and 38b. The pressure-receiving portion 30 protrudes from the main body of the diaphragm 23 and contacts the piezoelectric elements 38a and 38b. The pressure-receiving portion 30 may also be called a convex portion, a protruding portion, or a projection.

[0048] The center S of the pressure-receiving portion 30 in the X direction preferably coincides with the centers of the piezoelectric elements 38a and 38b in the X direction. In addition, 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 piezoelectric elements 38a and 38b.

[0049] A common electrode 41a is provided to the piezoelectric elements 38a and 38b. The common electrode 41a is electrically connected to a direction control circuit 42a. An individual electrode 41b is provided to the piezoelectric elements 38a and 38b. The individual electrode 41b is electrically connected to a drive circuit 42b.

[0050] A schematic configuration of the discharge head 20 in a YZ cross section will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of a YZ cross section of the discharge head according to the first embodiment (for example, a BB cross section in Fig. 3).

[0051] As shown in FIG. 5, an ink supply flow path 31 and an ink discharge flow path 32 are provided on the piezoelectric element 38a side (+Z side) of the diaphragm 23.

[0052] 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.

[0053] The ink supply flow path 31 and the ink inlet flow path 36 are connected via a hole 31a provided in the diaphragm 23, and ink supplied to the ink supply flow path 31 passes through the ink inlet flow path 36 via the hole 31a and is supplied to the pressure chamber 33.

[0054] The ink discharge flow path 32 and the ink outlet flow path 37 are connected via a hole 32a provided in the diaphragm 23, and ink discharged from the pressure chamber 33 to the ink outlet flow path 37 passes through the ink discharge flow path 32 via the hole 32a and is discharged from the ejection head 20.

[0055] The contact portion between the pressure receiving portion 30 and the piezoelectric element 38a will be described with reference to Fig. 6. Fig. 6 is an enlarged view of part A in Fig. 4 of the pressure receiving portion 30 according to the first embodiment.

[0056] The pressure-receiving portion 30 has a top portion 30a, a base portion 30b, a first portion 30c, and a second portion 30d.

[0057] The top 30a is in contact with the piezoelectric element 38a and is the upper surface (+Z side surface) of the pressure-receiving portion 30 that protrudes from the main body of the diaphragm 23. The width L3 of the piezoelectric element 38a in the X direction is larger than the width L1 of the top 30a in the X direction (L3>L1).

[0058] The width of piezoelectric element 38a may be larger than the width of top portion 30a in other directions on the XY plane. In other words, the width of piezoelectric element 38a is larger than the width of top portion 30a in at least one direction perpendicular to the Z direction in which piezoelectric element 38a presses diaphragm 23.

[0059] When the piezoelectric element 38a is deformed by the application of voltage, the top portion 30a is pressed in the -Z direction by the piezoelectric element 38a, and the diaphragm 23 is deformed. The deformed diaphragm 23 presses the pressure chamber 33 in the -Z direction. In other words, the piezoelectric element 38a presses the pressure chamber 33 in the -Z direction via the diaphragm 23. In this way, the pressure chamber 33 is pressed in the -Z direction, and ink stored in the pressure chamber 33 is ejected from the nozzle 34 in the -Z direction.

[0060] Furthermore, since the width L3 of the piezoelectric element 38a in the X direction is larger than the width L1 of the top portion 30a in the X direction (L3>L1), when the piezoelectric element 38a deforms, stress is applied uniformly to the entire top portion 30a. This stabilizes the deformation of the diaphragm 23, and therefore stabilizes the change in pressure in the pressure chamber 33. This stabilizes the ejection of ink from the inkjet device 1.

[0061] The base portion 30b corresponds to a portion that connects the pressure receiving portion 30 and the diaphragm 23 main body.

[0062] The pressure-receiving portion 30 has a first portion 30c whose width gradually increases from the width of the top portion 30a to reach the width of the base portion 30b, and a second portion 30d which is located closer to the piezoelectric element 38a than the first portion 30c and has the same width as the top portion 30a. In other words, the pressure-receiving portion 30 has a step between the top portion 30a and the base portion 30b, and a tapered inclined surface which widens outward from the step toward the base 30b.

[0063] In the X direction, the width L1 of the top portion 30a in the X direction is smaller than the width L2 of the base portion 30b in the X direction (L1 <L2)。

[0064] The width of the top portion 30a may be smaller than the width of the base portion 30b in other directions on the XY plane. In other words, the width of the top portion 30a is smaller than the width of the base portion 30b in at least one direction perpendicular to the Z direction in which the piezoelectric element 38a presses the diaphragm 23.

[0065] Furthermore, when the length in the Z direction between the top 30a and base 30b of the pressure-receiving portion 30 is H, the height C in the Z direction of the first portion 30c is preferably 0.01H or more and H or less.

[0066] A comparison between a conventional pressure receiving section 300 and the pressure receiving section 30 of the first embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of the configuration of the conventional pressure receiving section 300.

[0067] Unlike the pressure receiving portion 30 of the first embodiment, the pressure receiving portion 300 does not have a tapered inclined surface between the top portion 300a and the base portion 300b, and the surface of the main body of the diaphragm 23 intersects at a right angle with the side surface of the pressure receiving portion 300. In other words, the width L101 of the top portion 30a in the X direction is equal to the width L102 of the base portion 300b in the X direction (L101=L102).

[0068] When the diaphragm 23 equipped with the conventional pressure-receiving portion 300 is deformed, stress tends to concentrate at portions A and B of the pressure-receiving portion 300 more easily than in the first embodiment, which may reduce the resistance of the diaphragm 23 to deterioration or damage caused by deformation. In addition, ink ejection from the inkjet device 1 may become unstable, which may result in a decrease in print quality.

[0069] In the first embodiment, the pressure-receiving portion 30 has a tapered inclined surface on its side, which alleviates stress concentration at the portions A and B of the diaphragm 23. This increases the resistance of the diaphragm 23 to deterioration and damage due to deformation.

[0070] (First Modification) The pressure receiving portion 301 of the first modified example will be described with reference to Fig. 8. Fig. 8 is a diagram showing an example of the configuration of the pressure receiving portion 301 of the first modified example.

[0071] The pressure-receiving portion 301 has a top portion 301a, a base portion 301b, and a first portion 301c. The top portion 301a and the base portion 301b are similar to the top portion 30a and the base portion 30b in the first embodiment.

[0072] Unlike the pressure-receiving portion 30 of the first embodiment, the pressure-receiving portion 301 of the first modification has no step between the top portion 301a and the base portion 301b, and has a first portion 301c whose width gradually increases from the width of the top portion 301a to the width of the base portion 301b. The width of the first portion 301c increases linearly toward the base portion 301b.

[0073] That is, the pressure-receiving portion 301 has a tapered inclined surface that widens outward from the top portion 301a to the base portion 301b. As a result, the width L111 of the top portion 301a in the X direction is shorter than the width L112 of the base portion 301b in the X direction (L111 <L112)。

[0074] The width of top portion 301a may be smaller than the width of base portion 301b in other directions on the XY plane. In other words, the width of top portion 301a is smaller than the width of base portion 301b in at least one direction perpendicular to the Z direction in which piezoelectric element 38a presses diaphragm 23.

[0075] In the first modified example, as in the first embodiment, the pressure-receiving portion 301 has a structure that alleviates stress concentration on areas A and B when pressed by the piezoelectric element 38a, and therefore the same effect as in the first embodiment can be obtained in the first modified example.

[0076] (Second Modification) The pressure receiving portion 302 of the second modified example will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of the configuration of the pressure receiving portion 302 of the second modified example.

[0077] The pressure-receiving portion 302 has a top portion 302a, a base portion 302b, a first portion 302c, and a second portion 302d. The top portion 302a and the base portion 302b are similar to the top portion 30a and the base portion 30b in the first embodiment.

[0078] Similar to the pressure receiving portion 30 of the first embodiment, the pressure receiving portion 302 of the second modified example has a first portion 302c whose width gradually increases from the width of the top portion 302a to the width of the base portion 302b, and a second portion 302d, which is located closer to the piezoelectric element 38a than the first portion 302c and has the same width as the top portion 302a. The width of the first portion 302c increases in a curved manner toward the base portion 302b.

[0079] That is, the pressure-receiving portion 302 has a curved surface that spreads 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)。

[0080] The width of the top portion 302a may be smaller than the width of the base portion 302b in other directions on the XY plane. In other words, the width of the top portion 302a is smaller than the width of the base portion 302b in at least one direction perpendicular to the Z direction in which the piezoelectric element 38a presses the diaphragm 23.

[0081] 9 is an arc, the radius of curvature of the arc is preferably not less than 0.01H and not more than H. If the radius of curvature of the arc is H, the first portion 302c does not exist.

[0082] In the second modified example, as in the first embodiment, the pressure-receiving portion 302 has a structure that alleviates stress concentration on areas A and B when pressed by the piezoelectric element 38a, and therefore the same effect as in the first embodiment can be obtained in the second modified example.

[0083] (Third Modification) A pressure receiving portion 303 of the third modified example will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of the configuration of the pressure receiving portion 303 in the third modified example.

[0084] The pressure-receiving portion 303 of the third modification has a film 303e on the piezoelectric element 38a side of the diaphragm 23. The diaphragm 23 also has films 303f with uniform thickness on the surfaces on both sides of the film 303e. The films 303e and 303f function as protective films that protect the diaphragm 23.

[0085] The pressure receiving portion 303 has a top portion 303a, a base portion 303b, a first portion 303c, and a second portion 303d. The top portion 303a is similar to the top portion 30a in the first embodiment. The base portion 303b corresponds to a portion that connects the membrane 303e and the main body of the pressure receiving portion 303 with the main body of the diaphragm 23.

[0086] As in the second modification, the membrane 303e of the pressure-receiving portion 303 has a first portion 303c whose width gradually increases from the width of the top portion 303a to the width of the base portion 303b, and a second portion 303d, which is located closer to the piezoelectric element 38a than the first portion 303c and has the same width as the top portion 303a of the pressure-receiving portion 303. The width of the first portion 303c increases in a curved manner toward the base portion 303b.

[0087] The pressure-receiving portion 303 has a curved surface that spreads outward from the top portion 303a to the base portion 303b. Therefore, the width L131 of the top portion 303a in the X direction is smaller than the width L132 of the base portion 303b in the X direction (L131 <L132)。

[0088] The width of the top portion 303a may be smaller than the width of the base portion 303b in other directions on the XY plane. In other words, the width of the top portion 303a is smaller than the width of the base portion 303b in at least one direction perpendicular to the Z direction in which the piezoelectric element 38a presses the diaphragm 23.

[0089] The film 303e is formed by, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), or the like using inorganic and organic materials.

[0090] For example, the film 303e may be made of an inorganic material such as SiO2 (silicon dioxide), Al2O3 (aluminum oxide), or TiO2 (titanium oxide), or an organic material such as parylene. The film 303e preferably has a thickness of 0.05 micrometers or more and 5 micrometers or less.

[0091] 10 is an arc, the radius of curvature of the arc is preferably not less than 0.01H and not more than H. If the radius of curvature of the arc is H, the first portion 303c does not exist.

[0092] In the third modified example, similarly to the first embodiment, the pressure-receiving portion 303 can reduce stress concentration on the portions A and B when pressed by the piezoelectric element 38a.

[0093] In the third modified example, as in the first embodiment, the pressure-receiving portion 303 has a structure that alleviates stress concentration on areas A and B when pressed by the piezoelectric element 38a, and therefore the same effect as in the first embodiment can be obtained in the third modified example.

[0094] (Fourth Modification) A pressure receiving portion 304 of the fourth modified example will be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of the configuration of the pressure receiving portion 304 of the fourth modified example.

[0095] The pressure-receiving portion 304 of the fourth modification has films 304e and 304f on the piezoelectric element 38a side of the diaphragm 23, and a film 304g on the pressure chamber 33 side of the diaphragm 23. The films 304e and 304f are similar to those of the third modification, and function as protective films that protect the diaphragm 23.

[0096] As in the third modification, the membrane 304e of the pressure-receiving portion 304 has a first portion 304c whose width gradually increases from the width of the top portion 304a to the width of the base portion 304b, and a second portion 304d, which is located closer to the piezoelectric element 38a than the first portion 304c and has the same width as the top portion 304a of the pressure-receiving portion 304. The width of the first portion 304c increases in a curved manner toward the base portion 304b.

[0097] As in the second modification, the membrane 304e of the pressure-receiving portion 304 has a first portion 304c whose width increases toward the base portion 304b and whose side surface is a curved surface, and a second portion 304d whose width is constant toward the base portion 304b. The width L141 of the top portion 304a in the X direction is smaller than the width L142 of the base portion 304b in the X direction (L141 <L142)。

[0098] The width of the top portion 304a may be smaller than the width of the base portion 304b in other directions on the XY plane. In other words, the width of the top portion 304a is smaller than the width of the base portion 304b in at least one direction perpendicular to the Z direction in which the piezoelectric element 38a presses the diaphragm 23.

[0099] Similarly to the third modification, the films 304e, 304f, and 304g are formed by CVD, PVD, or the like using inorganic and organic materials.

[0100] In the fourth modified example, as in the first embodiment, the pressure-receiving portion 304 has a structure that alleviates stress concentration on areas A and B when pressed by the piezoelectric element 38a, and therefore the same effect as in the first embodiment can be obtained in the fourth modified example.

[0101] <Second embodiment> Referring to Fig. 12, the piezoelectric element 38b disposed on the upper part of the partition wall 35 will be described. Fig. 12 is an enlarged view of part B in Fig. 4. In the second embodiment, the configuration of the piezoelectric element 38b that supports the partition wall 35 via the diaphragm 23 is different from that in the first embodiment.

[0102] The piezoelectric element 38b is provided with a common electrode 41a and individual electrodes 41b. The common electrode 41a (first electrode) is electrically connected to a first wiring 51a, and the individual electrode 41b (second electrode) is electrically connected to a second wiring 51b.

[0103] The common electrode 41a applies a voltage Va to the piezoelectric element 38b via the first wiring 51a, and the individual electrode 41b applies a voltage Vb, which is lower than the voltage Va, to the piezoelectric element 38b via the second wiring 51b. For example, the voltage Va may be +V1 volts, and the voltage Vb may be -V1 volts. The first wiring 51a and the second wiring 51b are connected to electrodes of opposite polarities.

[0104] The piezoelectric element 38b also has a movable portion 56, a first end portion 57a, and a second end portion 57b.

[0105] The movable portion 56 is a portion near the center of the piezoelectric element 38b, and includes both first wiring 51a electrically connected to the common electrode 41a and second wiring 51b electrically connected to the individual electrodes 41b. Within the movable portion 56, the first wiring 51a and the second wiring 51b are alternately arranged in the Z direction.

[0106] Therefore, when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, a potential difference occurs between the first wiring 51a and the second wiring 51b, causing electric polarization in the movable portion 56. This electric polarization causes deformation of the movable portion 56. In other words, when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, the movable portion 56 of the piezoelectric element 38b deforms.

[0107] The first end 57a is the end portion of the piezoelectric element 38b on the common electrode 41a side, and includes the first wiring 51a electrically connected to the common electrode 41a. The first end 57a does not include the second wiring 51b electrically connected to the individual electrode 41b. Therefore, when voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, electric polarization is not generated in the first end 57a. Therefore, although the first end 57a is somewhat affected by the deformation of the movable part 56, it does not deform significantly.

[0108] The second end 57b is a portion of the piezoelectric element 38b on the end side facing the individual electrode 41b, and includes the 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 voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b, electric polarization is not generated in the second end 57b. Therefore, although the second end 57b is somewhat affected by the deformation of the movable part 56, it does not deform significantly.

[0109] The end regions (first end 57a and second end 57b) of the 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.

[0110] Furthermore, piezoelectric element 38b has an end region that is not driven in the X direction. Piezoelectric element 38b may also have an end region that is not driven in other directions on the XY plane. In other words, piezoelectric element 38b has an end region that is not driven in at least one direction perpendicular to the Z direction in which diaphragm 23 is pressed.

[0111] The first end 57a and the second end 57b have step-shaped first chamfered portions 58a and second chamfered portions 58b at the corners of the first end 57a and the second end 57b on the diaphragm 23 side.

[0112] Since the corners on the diaphragm 23 side are stepped, the first end 57a and the second end 57b are less likely to deform, and stress concentration on the portions A and B can be alleviated.

[0113] The deformation of the piezoelectric element 38b when the voltages Va and Vb are applied to the common electrode 41a and the individual electrode 41b will be described in more detail with reference to Fig. 13. Fig. 13 is a schematic diagram showing an example of the degree of deformation of the piezoelectric element according to the second embodiment.

[0114] 13, the magnitude of deformation d of piezoelectric element 38b is indicated by the length of the arrow. The greater the magnitude of deformation d of piezoelectric element 38b, the longer the arrow. Furthermore, deformation of piezoelectric element 38b in the -Z direction is considered positive.

[0115] In the movable portion 56 of the piezoelectric element 38b, the magnitude of deformation d of the piezoelectric element 38b decreases from near the center to the end region. Near the center of the movable portion 56, the magnitude of deformation d of the piezoelectric element 38b is maximum, and this maximum value is defined as dmax.

[0116] On the other hand, the end region of the piezoelectric element 38b is difficult to deform and therefore functions as a fixed end.

[0117] By setting the distribution of the magnitude of deformation in this way, it is possible to alleviate the stress concentration on the portions A and B shown in Fig. 13. Furthermore, by having the first chamfered portion 58a and the second chamfered portion 58b on the first end portion 57a ​​and the second end portion 57b, it is possible to make the first end portion 57a ​​and the second end portion 57b even more difficult to deform, and it is possible to further alleviate the stress concentration on the portions A and B.

[0118] If the width of the movable portion 56 in the X direction is W1, it is preferable that W1 be equal to or greater than 500 micrometers and equal to or less than 2000 micrometers.

[0119] If the width of the first end 57a and the second end 57b in the X direction is W2, W2 is preferably 100 micrometers or more and 200 micrometers or less.

[0120] If the chamfer width in the X direction of the first chamfered portion 58a and the second chamfered portion 58b is W3, W3 is preferably 20 micrometers or more and 100 micrometers or less.

[0121] If the chamfer height in the Z direction of the first chamfered portion 58a and the second chamfered portion 58b is H3, H3 is preferably 20 micrometers or more and 200 micrometers or less.

[0122] The maximum value dmax of the deformation magnitude d of the piezoelectric element 38b is preferably 0.2 micrometers or more and 2 micrometers or less.

[0123] Furthermore, W2 / dmax is preferably 100 or more and 1000 or less, and W2 / W3 is preferably 1 or more and 10 or less.

[0124] As shown in FIG. 14, the first end 57a and the second end 57b may have linear first chamfered portions 581a and second chamfered portions 581b at the corners of the first end 57a and the second end 57b on the diaphragm 23 side.

[0125] Also, as shown in FIG. 15, the first end 57a and the second end 57b may have arc-shaped first chamfered portions 582a and second chamfered portions 582b at the corners of the first end 57a and the second end 57b on the diaphragm 23 side.

[0126] Even if the corners have such a shape, the first end 57a and the second end 57b are less likely to deform, and the stress concentration on the portions A and B can be alleviated.

[0127] In the second embodiment, the piezoelectric element 38b has the first end 57a and the second end 57b that are not driven, but the piezoelectric element 38a shown in FIG. 4 may have areas corresponding to the first end 57a and the second end 57b.

[0128] <Third embodiment> The contact between the pressure receiving portion 30 and the piezoelectric element 38a will be described with reference to Figures 16 to 19. Figures 16 to 18 are diagrams showing the pressure receiving portion 30 and the piezoelectric element 38a according to the third embodiment.

[0129] The pressure receiving portion 30 and the piezoelectric element 38a of the third embodiment have the same configuration as those of the first embodiment, and therefore, a description of the configuration of the pressure receiving portion 30 and the piezoelectric element 38a will be omitted.

[0130] In the third embodiment, the piezoelectric element 38a contacts the top portion 30a of the pressure-receiving portion 30, as in the first embodiment (see, for example, FIG. 6).

[0131] The width of the apex 30a may be smaller in other directions on the XY plane than the width of the piezoelectric element 38a in the X direction. In other words, the width of the apex 30a is smaller than the width of the piezoelectric element 38a in at least one direction perpendicular to the Z direction in which the piezoelectric element 38a presses the diaphragm 23.

[0132] For example, when the difference between L3 and L1 is defined as a difference d (d=L3−L1), the difference d is preferably equal to or greater than 1 micrometer and equal to or less than 100 micrometers.

[0133] For example, due to manufacturing variations in the inkjet device 1, the piezoelectric element 38a may be shifted to the left with respect to the apex 30a as shown in Fig. 17. Also, for example, as shown in Fig. 18, the piezoelectric element 38a may be shifted to the right with respect to the apex 30a.

[0134] 16 to 18, the contact area between the top 30a and the piezoelectric element 38a does not change, and therefore the stress applied to the top 30a by the piezoelectric element 38a does not change. This stabilizes the deformation of the diaphragm 23, and stabilizes the change in pressure in the pressure chamber 33. This stabilizes the ejection of ink from the inkjet device 1.

[0135] For example, as shown in Fig. 19, if the piezoelectric element 38a is significantly misaligned with respect to the apex 30a due to manufacturing variations in the inkjet device 1, the area of ​​the contact portion P where the apex 30a and the piezoelectric element 38a are in contact will be smaller than in the cases of Figs. 16 to 18. Furthermore, the width Pa of the contact portion P in the X direction will be smaller by the width La (Pa = L1 - La).

[0136] Since the force applied by the piezoelectric element 38a is constant, when the area of the contact portion P changes in this way, the stress applied to the diaphragm 23 becomes non-uniform. As a result, the degree of stress concentration at sites A and B increases.

[0137] In the third embodiment, even when the piezoelectric element 38a is somewhat displaced with respect to the top portion 30a, since the width L1 of the top portion 30a in the X direction is smaller than the width L3 of the piezoelectric element 38a in the X direction (L1 < L3), the inkjet device 1 has a structure capable of maintaining the area of the contact portion P. For this reason, the inkjet device 1 can obtain the effect of alleviating the concentration of stress on sites A and B of the diaphragm 23.

[0138] <Summary of the Embodiment> As described above, the inkjet device of the present embodiment includes a partition wall that separates a pressure chamber for storing ink discharged from a nozzle, a piezoelectric element that presses the pressure chamber via a diaphragm, and a diaphragm that applies pressure to a pressure chamber communicating with the nozzle that discharges ink when pressed by the piezoelectric element. The diaphragm has a pressure receiving portion whose top is in contact with the piezoelectric element and whose base is connected to the main body of the diaphragm. In at least one direction perpendicular to the direction in which the piezoelectric element presses the diaphragm, the width of the base is larger than the width of the top.

[0139] With this configuration, when the piezoelectric elements 38a and 38b to which a voltage is applied deform the diaphragm 23, the concentration of stress on sites A and B of the diaphragm 23 is alleviated.

[0140] In the above-described embodiment, the notation “... portion” used for each component may be replaced with other notations such as “... assembly”, “... device”, “... unit”, or “... module”.

[0141] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims. It is understood that such modifications or alterations also fall within the technical scope of the present disclosure. Furthermore, the components in the embodiments may be combined in any manner without departing from the spirit of the present disclosure. [Industrial Applicability]

[0142] The present disclosure is useful as an inkjet device. [Explanation of symbols]

[0143] 1. Inkjet device 2 bases 3 Guide 4 Transport table 5 Gantry 6 Line Head 7 Printing material 8 Drive unit 20 Discharge head 21 Nozzle plate 22 Flow path plate 23 Diaphragm 24 Housing 25 Pressure fluctuation section 30 Pressure receiving part 30a top 30b base 31 Ink supply channel 32 Ink discharge channel 33 Pressure Chamber 34 nozzles 35 Bulkhead 36 Ink inlet channel 37 Ink outlet channel 38a Piezoelectric element 38b Piezoelectric element 39 Base 41a Common electrode 41b Individual electrode 42a Direction control circuit 42b Drive circuit 51a First wiring 51b 2nd wiring 56 Moving parts 57a First end 57b Second end 58a First chamfer 58b Second chamfer

Claims

1. a partition wall separating pressure chambers that store ink to be ejected from the nozzles; a piezoelectric element that presses the pressure chamber via a diaphragm; a diaphragm that applies pressure to a pressure chamber that communicates with the nozzle that ejects ink when pressed by the piezoelectric element; Equipped with the diaphragm has a pressure-receiving portion whose top portion is in contact with the piezoelectric element and whose base portion is connected to the main body of the diaphragm; a width of the base portion is greater than a width of the top portion in at least one direction perpendicular to a direction in which the piezoelectric element presses the diaphragm; Inkjet device.

2. The pressure-receiving portion includes at least a first portion whose width gradually increases from the width of the top portion to the width of the base portion. The inkjet device according to claim 1 .

3. the pressure-receiving portion further includes a second portion located closer to the piezoelectric element than the first portion, the second portion having a width equal to the width of the top portion; The inkjet device according to claim 2 .

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

5. The width of the first portion of the pressure-receiving portion increases in a curved manner. The inkjet device according to claim 2 .

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

7. the diaphragm has a protective film on the surface facing the pressure chamber; The ink jet device according to claim 6 .

8. the piezoelectric element has a non-actuating end region in at least one direction perpendicular to the direction in which the piezoelectric element presses against the diaphragm; The inkjet device according to claim 1 .

9. One of a first wiring and a second wiring connected to electrodes of opposite polarity is provided in the end region of the piezoelectric element, and both the first wiring and the second wiring are provided closer to the center of the piezoelectric element than the end region. The inkjet device according to claim 8 .

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

11. a width of the top portion being smaller than a width of the piezoelectric element in at least one direction perpendicular to a direction in which the piezoelectric element presses the diaphragm; The inkjet device according to claim 1 .

12. a partition wall separating pressure chambers that store ink to be ejected from the nozzles; a piezoelectric element that presses the pressure chamber via a diaphragm; a diaphragm that applies pressure to a pressure chamber that communicates with the nozzle that ejects ink when pressed by the piezoelectric element; Equipped with the piezoelectric element has a non-actuating end region in at least one direction perpendicular to the direction in which the piezoelectric element presses against the diaphragm; Inkjet device.

13. One of a first wiring and a second wiring connected to electrodes of opposite polarity is provided in the end region of the piezoelectric element, and both the first wiring and the second wiring are provided closer to the center of the piezoelectric element than the end region. The inkjet device according to claim 12.

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

15. a partition wall separating pressure chambers that store ink to be ejected from the nozzles; a piezoelectric element that presses the pressure chamber via a diaphragm; a diaphragm that applies pressure to a pressure chamber that communicates with the nozzle that ejects ink when pressed by the piezoelectric element; Equipped with the diaphragm has a pressure-receiving portion whose top portion is in contact with the piezoelectric element, a width of the top portion being smaller than a width of the piezoelectric element in at least one direction perpendicular to a direction in which the piezoelectric element presses the diaphragm; Inkjet device.

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