Liquid ejecting head and liquid ejecting apparatus

Abstract

The present application provides a kind of liquid ejection head and liquid ejection device for improving the ink weight of droplet ejected from nozzle and the resonance frequency of vibration plate.The liquid ejection head is, pressure chamber, vibration plate with first vibration plate, second vibration plate and third vibration plate, liquid ejection head with piezoelectric actuator stacked in sequence, in the plan view from the stacking direction of the vibration plate and the piezoelectric actuator, the pressure chamber is provided with multiple in first direction side by side, in the first direction, in the first vibration plate and the second vibration plate, the part of piezoelectric layer and the third vibration plate is stacked, and the part of piezoelectric layer and the third vibration plate is not stacked, one of the first vibration plate and the second vibration plate has compressive stress, and the other has tensile stress, the Young's modulus of the third vibration plate is greater than the Young's modulus of the first vibration plate and the second vibration plate.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid ejection head that ejects liquid droplets and a liquid ejection apparatus, and particularly to an inkjet recording head that ejects ink as liquid and an inkjet recording apparatus. BACKGROUND

[0002] As a representative example of a liquid ejection head, there is an inkjet recording head that ejects ink droplets as liquid. As an inkjet recording head, for example, there is known an inkjet recording head that has a flow channel substrate in which pressure chambers communicating with nozzles are formed, and a piezoelectric actuator that is provided on one face side of the flow channel substrate via a vibration plate, and that causes ink in the pressure chambers to generate a pressure change by the piezoelectric actuator, thereby ejecting ink droplets from the nozzles.

[0003] The piezoelectric actuator has a first electrode formed on the vibration plate of the flow channel forming substrate, a piezoelectric layer formed on the first electrode using a piezoelectric material having an electro-mechanical conversion characteristic, and a second electrode provided on the piezoelectric layer (for example, refer to Patent Document 1).

[0004] However, there is a problem that when the Young's modulus of the vibration plate is reduced in order to increase the ink weight of the droplets ejected from the nozzles, the resonance frequency of the vibration plate also decreases, thereby failing to perform continuous ejection of ink droplets at high speed.

[0005] In addition, such a problem does not only exist in the inkjet recording head, but also exists in a liquid ejection head that ejects liquid other than ink.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-139331 SUMMARY

[0007] The present application that solves the above-described problem is characterized by a liquid ejection head in which a pressure chamber, a vibration plate having a first vibration plate, a second vibration plate, and a third vibration plate, and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode are stacked in this order, in a plan view in a stacking direction of the vibration plate and the piezoelectric actuator, the pressure chamber is provided with a plurality of chambers in a first direction in parallel, in the first direction, a portion in which the piezoelectric layer and the third vibration plate are stacked and a portion in which the piezoelectric layer and the third vibration plate are not stacked are provided in the first vibration plate and the second vibration plate, one of the first vibration plate and the second vibration plate has a compressive stress, the other has a tensile stress, and the Young's modulus of the third vibration plate is greater than the Young's modulus of the first vibration plate and the second vibration plate.

[0008] Further, another aspect of the present embodiment is a liquid ejecting apparatus including the liquid ejecting head according to the above aspect. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 Exploded perspective view of a recording head according to Embodiment 1 of the present invention.

[0010] Figure 2 Plan view of a recording head according to Embodiment 1 of the present invention.

[0011] Figure 3 Sectional view of a recording head according to Embodiment 1 of the present invention.

[0012] Figure 4 Main portion sectional view of a recording head according to Embodiment 1 of the present invention.

[0013] Figure 5 Main portion sectional view of a recording head according to Embodiment 1 of the present invention.

[0014] Figure 6 Main portion sectional view of a recording head according to Embodiment 1 of the present invention.

[0015] Figure 7 Main portion sectional view of a recording head according to Embodiment 2 of the present invention.

[0016] Figure 8 Main portion plan view of a recording head according to Embodiment 3 of the present invention.

[0017] Figure 9 Main portion sectional view of a recording head according to Embodiment 3 of the present invention.

[0018] Figure 10 FIG. 1 is a diagram showing an outline structure of a recording apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, the present application will be described in detail based on embodiments. However, the following description is a description indicating one embodiment of the present application, and can be arbitrarily changed within the scope of the present application. Components to which the same reference signs are assigned in each drawing represent the same components, and the description will be appropriately omitted. Further, in each drawing, X, Y, Z represent three spatial axes orthogonal to each other. In the present specification, the directions along these axes are set as the X direction, the Y direction, and the Z direction. The direction toward which the arrow mark of each drawing is set as the positive (+) direction, and the opposite direction of the arrow mark is set as the negative (-) direction, and the description will be made. Also, for the three X, Y, Z spatial axes for which the positive direction and the negative direction are not limited, the description will be made by setting as the X axis, the Y axis, the Z axis. Further, the Z direction represents the vertical direction, the +Z direction represents the vertically downward direction, and the -Z direction represents the vertically upward direction.

[0020] Embodiment 1

[0021] Figure 1 An exploded perspective view of an inkjet recording head as one example of a liquid ejection head in Embodiment 1 of the present application. Figure 2 A plan view of the recording head. Figure 3 A plan view of the recording head. Figure 2 A cross-sectional view of the A-A' line of the recording head. Figure 4 A cross-sectional view of the B-B' line of the recording head. Figure 2 A cross-sectional view of the B-B' line of the recording head. Figure 5 A cross-sectional view of the B-B' line of the recording head. Figure 6 A cross-sectional view for explaining the internal stress of the vibrating plate.

[0022] As shown in the drawings, in an inkjet recording head 1 (hereinafter, also simply referred to as the recording head 1) as one example of a liquid ejection head of the present embodiment, a flow path forming substrate 10 is provided as one example of a "substrate". The flow path forming substrate 10 is constituted of a silicon substrate, a glass substrate, an SOI (Silicon-On-Insulator) substrate, various ceramic substrates. The flow path forming substrate 10 of the present embodiment is constituted of a single crystal silicon. In addition, the flow path forming substrate 10 can be a substrate in which a (100) plane is preferentially oriented, or a substrate in which a (110) plane is preferentially oriented.

[0023] In the flow passage forming substrate 10, a plurality of pressure chambers 12 are arranged side by side along the +X direction as the "first direction". That is, the "first direction" is the "side-by-side arrangement direction" of the pressure chambers 12, and in the present embodiment, is the +X direction. The plurality of pressure chambers 12 are arranged on a straight line along the +X direction in such a manner that the positions in the +Y direction become the same positions. The pressure chambers 12 adjacent to each other in the +X direction are divided by the partition walls 11. Of course, the arrangement of the pressure chambers 12 is not particularly limited thereto, and for example, in the pressure chambers 12 arranged side by side in the +X direction, a so-called staggered arrangement in which every other pressure chamber is arranged at a position shifted in the +Y direction can also be employed.

[0024] Further, the pressure chamber 12 of the present embodiment has an elongated shape in which the direction intersecting the +X direction as the side-by-side arrangement direction is elongated when viewed from the top in the +Z direction. That is, the pressure chamber 12 has a shape in which the +X direction as the side-by-side arrangement direction is the short side direction and the direction intersecting the +X direction, that is, the +Y direction in the present embodiment, is the long side direction when viewed from the top in the +Z direction. Further, the pressure chamber 12 of the present embodiment has a rectangular shape in which the +Y direction is the long side direction when viewed from the top in the +Z direction. Of course, the shape of the pressure chamber 12 when viewed from the top in the Z direction is not particularly limited thereto, and the pressure chamber 12 can be a parallelogram shape, can be a so-called rounded rectangular shape in which both end portions in the long side direction are rounded shapes based on the rectangular shape, or an oval arc shape such as an elliptical shape or an oval shape, or a circular shape, a polygonal shape, or the like. In this way, the pressure chamber 12 can be arranged at a high density on the flow passage forming substrate 10 by arranging the plurality of pressure chambers 12 side by side in the +X direction with the +X direction as the short side direction when viewed from the +Z direction. The pressure chamber 12 corresponds to the "recess" provided on the "substrate".

[0025] On the inner wall surface of the pressure chamber 12 of such a flow passage forming substrate 10, a flow passage protection film 13 having liquid resistance, that is, having ink resistance is provided. The ink resistance here means etching resistance with respect to an alkaline ink. As such a flow passage protection film 13, for example, an object in which at least one material selected from the group consisting of tantalum oxide (TaO X ), zirconium oxide (ZrO X ), nickel (Ni), and chromium (Cr) is provided as a single layer or is laminated can be used. Further, as the flow passage protection film 13, a resin can also be used. In the present embodiment, tantalum pentoxide (TaO5) is used as the flow passage protection film 13.

[0026] On the +Z direction side of the flow passage forming substrate 10, a communication plate 15 and a nozzle plate 20 are laminated in this order.

[0027] In the communication plate 15, a nozzle communication passage 16 that communicates the pressure chamber 12 and the nozzle 21 is provided.

[0028] Further, in the communication plate 15, a first manifold portion 17 and a second manifold portion 18 that constitute a part of a manifold 100 that becomes a common liquid chamber that the plurality of pressure chambers 12 commonly communicate are provided. The first manifold portion 17 is provided in a manner that penetrates the communication plate 15 in the +Z direction. Further, the second manifold portion 18 is provided in a manner that does not penetrate the communication plate 15 in the +Z direction but opens on the face of the +Z direction side.

[0029] Further, in the communication plate 15, a supply communication passage 19 that communicates with the end portion of the Y axis of the pressure chamber 12 is provided independently for each of the pressure chambers 12. The supply communication passage 19 communicates the second manifold portion 18 and the pressure chamber 12, thereby supplying the ink in the manifold 100 to the pressure chamber 12.

[0030] As such a communication plate 15, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate such as a stainless steel substrate, or the like can be used. In addition, it is preferable that the communication plate 15 use a material that has substantially the same thermal expansion rate as the flow passage formation substrate 10. By causing the flow passage formation substrate 10 and the communication plate 15 to use a material that has substantially the same thermal expansion rate in this way, it is possible to reduce the occurrence of warping due to heat due to differences in thermal expansion rates.

[0031] The nozzle plate 20 is provided on the face of the communication plate 15 on the side opposite the flow passage formation substrate 10, that is, the +Z direction side.

[0032] On the nozzle plate 20, the nozzles 21 that communicate with each of the pressure chambers 12 via the nozzle communication passage 16 are formed. In the present embodiment, for the plurality of nozzles 21, nozzle rows in which the nozzles 21 that are arranged side by side in the +X direction are provided in two rows separated in the +Y direction. That is, the plurality of nozzles 21 of each row are arranged in a manner that the positions in the +Y direction become the same position. Of course, the arrangement of the nozzles 21 is not particularly limited to this, and, for example, it can be configured so that, among the nozzles 21 arranged side by side in the +X direction, every other nozzle is arranged at a position offset in the +Y direction, that is, so-called staggered arrangement. As such a nozzle plate 20, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate such as a stainless steel substrate, an organic substance such as a polyimide resin, or the like can be used. In addition, it is preferable that the nozzle plate 20 use a material that has substantially the same thermal expansion rate as the communication plate 15. By causing the nozzle plate 20 and the communication plate 15 to use a material that has substantially the same thermal expansion rate in this way, it is possible to reduce the occurrence of warping due to heat due to differences in thermal expansion rates.

[0033] Further, on the -Z direction side surface of the communication plate 15, a housing member 40 is fixed. In the housing member 40, a third manifold portion 42 that communicates with the first manifold portion 17 is provided. Also, by the first manifold portion 17 and the second manifold portion 18 provided in the communication plate 15, and the third manifold portion 42 provided in the housing member 40, a manifold 100 of the present embodiment is constituted. The manifold 100 is provided in a continuous manner in the +X direction that is the direction in which the pressure chambers 12 are arranged side by side, and the supply communication passages 19 that communicate the respective pressure chambers 12 and the manifold 100 are arranged side by side in the +X direction. Further, on the housing member 40, an inlet port 44 for communicating with the manifold 100 and supplying ink to the respective manifolds 100 is provided. Further, on the housing member 40, a connection port 43 that communicates with the through hole 32 of the protection substrate 30, which will be described later in detail, and allows the wiring substrate 120 to be inserted therethrough is provided.

[0034] Further, on the +Z direction side surface of the communication plate 15 on which the first manifold portion 17 and the second manifold portion 18 are opened, a plastic substrate 45 is provided. The plastic substrate 45 seals the openings of the +Z direction side of the first manifold portion 17 and the second manifold portion 18. In the present embodiment, such a plastic substrate 45 is provided with a sealing film 46 composed of a thin film having flexibility, and a fixed substrate 47 composed of a hard material such as metal. Since the region of the fixed substrate 47 that opposes the manifold 100 becomes an opening portion 48 that is completely removed in the thickness direction, one surface of the manifold 100 becomes a flexible portion, i.e., a plastic portion 49, that is sealed only by the sealing film 46 having flexibility. By the plastic portion 49 flexibly deforming to thereby absorb the pressure variation of the ink in the manifold 100.

[0035] On the -Z direction side surface of the flow path forming substrate 10, a vibration plate 50, and a piezoelectric actuator 300 having a first electrode 60, a piezoelectric body layer 70, and a second electrode 80 are laminated in this order. That is, the pressure chamber 12, the vibration plate 50, the first electrode 60, the piezoelectric body layer 70, and the second electrode 80 are arranged side by side in this order in the -Z direction.

[0036] The vibration plate 50 is provided with a first vibration plate 51, a second vibration plate 52, and a third vibration plate 53. The first vibration plate 51, the second vibration plate 52, and the third vibration plate 53 are laminated together in this order in the -Z direction.

[0037] The first vibrating plate 51 is a vibrating plate provided on the -Z-direction side face of the flow passage forming substrate 10, and is provided so as to be continuous across the entire -Z-direction side face of the flow passage forming substrate 10. That is, the first vibrating plate 51 is in contact with the partition wall 11 of the flow passage forming substrate 10 composed of single crystal silicon. That is, the first vibrating plate 51 is provided directly on the -Z-direction side face of the flow passage forming substrate 10. In the present embodiment, the first vibrating plate 51 is provided so as to be continuous across the entire -Z-direction side face of the flow passage forming substrate 10.

[0038] The second vibrating plate 52 is provided on the -Z-direction side face of the first vibrating plate 51. The second vibrating plate 52 is provided so as to be continuous across the entire -Z-direction side face of the first vibrating plate 51.

[0039] The third vibrating plate 53 is a vibrating plate provided on the -Z-direction side face of the second vibrating plate 52. The third vibrating plate 53 is provided locally in the +X-direction, which is the direction of arrangement of the pressure chambers 12 and the short side direction, at a portion overlapping the pressure chamber 12 when viewed from the +Z-direction. That is, the vibrating plate 50 has a portion in which the first vibrating plate 51, the second vibrating plate 52, and the third vibrating plate 53 are laminated in the +X-direction, and a portion in which the first vibrating plate 51 and the second vibrating plate 52 are laminated without the third vibrating plate 53. Here, in the present embodiment, a region of the vibrating plate 50 that opposes the pressure chamber 12 is referred to as a flexible region P. A region of the flexible region P that is on the inner side in the +X-direction when viewed in the +Z-direction and that does not include the central portion of the pressure chamber 12, as compared to the wall surface that is the end portion of the pressure chamber 12, is referred to as an edge portion P1. Further, a region of the flexible region P other than the edge portion P1 is referred to as a central portion P2. Also, in the present embodiment, the first vibrating plate 51, the second vibrating plate 52, and the third vibrating plate 53 are laminated on the central portion P2. Further, on the edge portion P1, the third vibrating plate 53 is not provided, and the first vibrating plate 51 and the second vibrating plate 52 are laminated. In other words, the third vibrating plate 53 is provided only on the central portion P2 in the +X-direction, which is the direction of arrangement of the pressure chambers 12 and the short side direction, within the region that opposes the pressure chamber 12 in the +Z-direction. Further, the third vibrating plate 53 is not formed on the edge portion P1 in the direction along the X-axis within the region that opposes the pressure chamber 12 in the +Z-direction, that is, the edge portion P1 that is the end portion on the +X-direction side and the end portion on the -X-direction side, and only the first vibrating plate 51 and the second vibrating plate 52 are laminated thereon.

[0040] The Young's modulus s1, s2 of the first vibrating plate 51 and the second vibrating plate 52 is smaller than the Young's modulus s3 of the third vibrating plate 53. That is, the relation of s1 < s3, s2 < s3 is satisfied. Here, at least one of the first vibrating plate 51 and the second vibrating plate 52 contains silicon oxide or silicon. Here, the first vibrating plate 51 and the second vibrating plate 52 containing silicon oxide or silicon means that silicon oxide or silicon is contained as a main component, and other materials can be contained. Further, the first vibrating plate 51 and the second vibrating plate 52 containing silicon oxide or silicon as a main component means that silicon oxide or silicon is contained at 50% or more in mass percentage in each of the first vibrating plate 51 and the second vibrating plate 52. Such first vibrating plate 51 and second vibrating plate 52 containing silicon oxide or silicon are generally amorphous. Such first vibrating plate 51 and second vibrating plate 52 are composed of silicon dioxide (SiO2).

[0041] The flow passage of the pressure chamber 12 and the like of the present embodiment is formed by anisotropic etching of the flow passage formation substrate 10 from the surface on the +Z direction side, and the surface on the -Z direction side of the pressure chamber 12 is divided by the first vibrating plate 51. That is, by providing the first vibrating plate 51 containing silicon oxide as the vibrating plate 50 on the flow passage formation substrate 10 side, the first vibrating plate 51 can be used as an etching stopper when anisotropic etching using an alkaline solution such as KOH is performed on the flow passage formation substrate 10 from the surface on the opposite side of the vibrating plate 50. Therefore, the pressure chamber 12 can be formed on the flow passage formation substrate 10 with high density and high precision by anisotropic etching, and the occurrence of a variation in the thickness of the vibrating plate 50 can be suppressed. Of course, the method of forming the pressure chamber 12 is not limited to anisotropic etching, and can be dry etching or the like. Further, the first vibrating plate 51 is not limited to a vibrating plate of silicon oxide. As the first vibrating plate 51, for example, a portion of the flow passage formation substrate 10 can be used. That is, as the first vibrating plate 51, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates can be used. Further, as the first vibrating plate 51, for example, zirconium oxide (ZrO x ), silicon nitride (Si3N4), titanium oxide (TiO x ), aluminum oxide (Al2O3), hafnium oxide (HfO xMagnesium oxide (MgO) and lanthanum aluminate (LaAlO3) are used as the first vibrating plate 51. Furthermore, the first vibrating plate 51 can also be an organic film such as polyimide or poly(p-xylylene). Additionally, the first vibrating plate 51 is not limited to an amorphous material; it can also be a material with a preferred crystalline structure, such as monocrystalline silicon. The second vibrating plate 52 is similar to the first vibrating plate 51. That is, it is preferable that at least one of the first vibrating plate 51 and the second vibrating plate 52 is amorphous. By making the first vibrating plate 51 and the second vibrating plate 52 amorphous in this way, it is possible for the first vibrating plate 51 and the second vibrating plate 52 to easily displace and be less prone to breakage.

[0042] Furthermore, preferably, the first vibrating plate 51 is made of a thermal oxide film. That is, by making the plurality of partitions 11 of the flow channel forming substrate 10 connected to the first vibrating plate 51 made of monocrystalline silicon, and making the first vibrating plate 51 made of a thermal oxide film, the adhesion between the partitions 11 and the first vibrating plate 51 can be improved.

[0043] In the first vibrating plate 51 and the second vibrating plate 52, one has compressive stress and the other has tensile stress. That is to say, there exists... Figure 5 As shown, the first vibrating plate 51 has compressive stress and the second vibrating plate 52 has tensile stress, and as shown... Figure 6 As shown, the first vibrating plate 51 has tensile stress and the second vibrating plate 52 has compressive stress. Furthermore, when it is said that one of the first vibrating plate 51 and the second vibrating plate 52 has compressive stress, it means that the internal stress is compressive. Similarly, when it is said that the other of the first vibrating plate 51 and the second vibrating plate 52 has tensile stress, it means that the internal stress is tensile.

[0044] In addition, such as Figure 5 As shown, when the first vibrating plate 51 has compressive stress and the second vibrating plate 52 has tensile stress, it is preferable that the thickness d1 of the first vibrating plate 51 along the Z-axis is greater than the thickness d2 of the second vibrating plate 52 (d1 > d2). This is because, generally, the compressive stress membrane is more prone to displacement than the tensile stress membrane. Therefore, by making the thickness d1 of the first vibrating plate 51 under compressive stress greater than the thickness d2 of the second vibrating plate 52 under tensile stress, the displacement of the vibrating plate 50 can be further increased.

[0045] In addition, such as Figure 6As shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more.

[0046] In addition, as shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more. Figure 5 Figure 6 In addition, as shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more.

[0047] In addition, as shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more. Figure 6 In addition, as shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more.

[0048] In addition, as shown in FIG. 1, the first vibrating plate 51 has a tensile stress and the second vibrating plate 52 has a compressive stress. In this case, the thickness d2 of the second vibrating plate 52 is preferably greater than the thickness dl of the first vibrating plate 51 (d2 > dl). That is, by making the thickness d2 of the second vibrating plate 52 having a compressive stress thicker than the thickness dl of the first vibrating plate 51 having a tensile stress, the displacement of the vibrating plate 50 can be increased more.

[0049] ​Preferably, such a third vibration plate 53 uses a material that also functions as a diffusion preventing layer that suppresses diffusion of components of the piezoelectric layer 70 to the second vibration plate 52, the first vibration plate 51, and the flow channel forming substrate 10 side. As the material of the third vibration plate 53, for example, an oxide containing zirconium, a nitride containing silicon, a silicon oxynitride, or the like can be cited. In the present embodiment, zirconium dioxide (Zr02) is used as the oxide containing zirconium. Note that, as long as the third vibration plate 53 includes the oxide containing zirconium, the nitride containing silicon, or the silicon oxynitride as a main component, it can also include other materials. Further, the main component of the third vibration plate 53 being the oxide containing zirconium, the nitride containing silicon, or the silicon oxynitride means that the oxide containing zirconium, the nitride containing silicon, or the silicon oxynitride included in the third vibration plate 53 is 50% or more in mass percentage. In the present embodiment, zirconium dioxide (Zr02) is used as the third vibration plate 53. By providing the third vibration plate 53 containing zirconium oxide in this way, it is possible to suppress diffusion of components contained in the piezoelectric layer 70, such as lead (Pb) or bismuth (Bi), or the like, to the first vibration plate 51, the second vibration plate 52, and the flow channel forming substrate 10, which are below the third vibration plate 53. Thus, by providing the third vibration plate 53 containing zirconium oxide, it is possible to suppress adverse conditions such as a decrease in rigidity due to diffusion of components contained in the piezoelectric layer 70 to the first vibration plate 51, the second vibration plate 52, and the flow channel forming substrate 10. Furthermore, by providing the third vibration plate 53 containing zirconium oxide, it is possible to suppress diffusion of components contained in the first vibration plate 51, the second vibration plate 52, and the flow channel forming substrate 10, or the like, which are disposed on the +Z direction side of the third vibration plate 53, to the piezoelectric layer 70 side.

[0050] Further, preferably, the third vibration plate 53 uses a material having insulating properties. By configuring the third vibration plate 53 from a material having insulating properties, it is possible to suppress short-circuiting of the first electrodes 60 provided for each active portion 310, which will be described later in detail, from each other due to the third vibration plate 53. Incidentally, even in the case where the first electrodes 60 are configured as common electrodes for a plurality of active portions 310, if the third vibration plate 53 has electrical conductivity, the third vibration plate 53 will apply an electric field to the piezoelectric layer 70 at portions other than the first electrodes 60, and thus it is preferable for the third vibration plate 53 to have a material having insulating properties.

[0051] On the -Z direction side surface of such a vibrating plate 50, a piezoelectric actuator 300 is provided which causes the vibrating plate 50 to be flexibly deformed, thereby causing the ink in the pressure chamber 12 to undergo a pressure change. The piezoelectric actuator 300 has a first electrode 60, a piezoelectric layer 70, and a second electrode 80 which are sequentially stacked from the +Z direction side of the vibrating plate 50 toward the -Z direction side. The piezoelectric actuator 300 is a pressure generating unit which causes the ink in the pressure chamber 12 to undergo a pressure change. Such a piezoelectric actuator 300 is also referred to as a piezoelectric element, and refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. Further, a portion in which a piezoelectric strain is generated in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In contrast, a portion in which a piezoelectric strain is not generated in the piezoelectric layer 70 is referred to as an inactive portion. That is, the active portion 310 refers to a portion in which the piezoelectric layer 70 is sandwiched by the first electrode 60 and the second electrode 80. In the present embodiment, the active portion 310 is formed for each pressure chamber 12 which is a recessed portion. That is, a plurality of active portions 310 are formed in the piezoelectric actuator 300. Further, in general, one of the electrodes of the active portion 310 is constituted as an independent electrode which is independent for each active portion 310, and the other electrode is constituted as a common electrode which is common to the plurality of active portions 310. In the present embodiment, the first electrode 60 is constituted as an independent electrode, and the second electrode 80 is constituted as a common electrode. Of course, the first electrode 60 can be constituted as a common electrode, and the second electrode 80 can be constituted as an independent electrode. A portion of the piezoelectric actuator 300 which opposes the pressure chamber 12 in the Z axis direction becomes a flexible portion, and an outer side portion of the pressure chamber 12 becomes an inflexible portion.

[0052] Specifically, as shown in Figure 2 and Figure 3 , the first electrode 60 is divided for each pressure chamber 12, thereby constituting an independent electrode which is independent for each active portion 310. The first electrode 60 is formed in the +X direction with a width which is narrower than the width of the pressure chamber 12. That is, in the +X direction, the end portion of the first electrode 60 is positioned at an inner side of a region which opposes the pressure chamber 12. Further, as shown in Figure 3 , in the Y axis direction of the first electrode 60, the end portion on the nozzle 21 side is disposed at an outer side compared to the pressure chamber 12. On the end portion of the first electrode 60 which is disposed at an outer side compared to the pressure chamber 12 in the Y axis direction, an independent lead electrode 91 which is a lead wire is connected.

[0053] As such a first electrode 60, a material having electrical conductivity, such as iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), chromium (Cr), nickel-chromium (NiCr), tungsten (W), titanium (Ti), titanium oxide (TiOX ), tungsten titanium (TiW), etc.

[0054] like Figure 2-4 As shown, the piezoelectric layer 70 is provided with a predetermined width in the +Y direction and is continuous across the +X direction. The width of the piezoelectric layer 70 in the +Y direction is longer than the length in the +Y direction, which is the long side of the pressure chamber 12. Therefore, the piezoelectric layer 70 extends to the outside of the area opposite to the pressure chamber 12 on both sides of the pressure chamber 12 in the +Y and -Y directions. The end of the piezoelectric layer 70 on the Y-axis opposite to the nozzle 21 is located on the outer side compared to the end of the first electrode 60. That is, the end of the first electrode 60 opposite to the nozzle 21 is covered by the piezoelectric layer 70. Furthermore, the end of the piezoelectric layer 70 on the nozzle 21 side is located on the inner side compared to the end of the first electrode 60, and the end of the first electrode 60 on the nozzle 21 side is not covered by the piezoelectric layer 70. In addition, at the end of the first electrode 60 extending to the outside of the piezoelectric layer 70, an independent lead electrode 91 made of gold (Au) or the like, as described above, is connected.

[0055] Furthermore, recesses 71 corresponding to each partition wall 11 are formed on the piezoelectric layer 70. The width of the recess 71 in the +X direction is wider than the width of the partition wall 11. Moreover, the recesses 71 are provided to penetrate the piezoelectric layer 70 and the third vibrating plate 53 in the +Z direction, which is the thickness direction. That is, the piezoelectric layer 70 is provided with a width in the +X direction that is the same as the width of the third vibrating plate 53, and the width of the third vibrating plate 53 in the +X direction is defined by the recesses 71. In other words, by making the width of the recesses 71 in the +X direction greater than the width of the partition wall 11, a central portion P2 in the vibrating plate 50, in which the first vibrating plate 51, the second vibrating plate 52, and the third vibrating plate 53 are stacked, and an edge portion P1 in the vibrating plate 50, in which the first vibrating plate 51 and the second vibrating plate 52 are stacked but the third vibrating plate 53 is not stacked, is formed. By providing the recess 71 in this manner, the rigidity of the portion of the vibrating plate 50 that faces the ends of the pressure chamber 12 in the +X and -X directions, i.e., the arm portion of the vibrating plate 50, is suppressed, thus enabling the piezoelectric actuator 300 to be displaced effectively. Furthermore, as described above, the piezoelectric layer 70 is only provided at the central portion P2 of the vibrating plate 50 where the third vibrating plate 53 is formed, and not at the edge portion P1 where the third vibrating plate 53 is not formed. Therefore, even if the third vibrating plate 53 is not formed at the edge portion P1, the diffusion of the piezoelectric layer 70 components into the second vibrating plate 52, the first vibrating plate 51, and the flow channel forming substrate 10 can be suppressed.

[0056] In addition, it is preferable that the Young's modulus of the flow passage protection film 13 provided to the inner wall of the pressure chamber 12 be smaller than the Young's modulus of the third vibrating plate 53. In the present embodiment, the Young's modulus of the tantalum pentoxide used as the flow passage protection film 13 is about 130 GPa, and the Young's modulus of the zirconium dioxide used as the third vibrating plate 53 is about 210 GPa. By making the Young's modulus of the flow passage protection film 13 smaller than the Young's modulus of the third vibrating plate 53 in this way, it is possible to suppress a decrease in the displacement of the vibrating plate 50.

[0057] Such a piezoelectric layer 70 is composed of a piezoelectric material made of a composite oxide of a perovskite structure represented by a general formula ABO3. In the present embodiment, lead zirconate titanate (PZT; Pb(Zr, Ti)O3) is used as the piezoelectric material. By using PZT as the piezoelectric material, it is possible to obtain a piezoelectric layer 70 having a large piezoelectric constant d31.

[0058] In the composite oxide of a perovskite structure represented by a general formula ABO3, oxygen is coordinated to 12 at the A site and to 6 at the B site, thereby forming an 8-hedron (octahedron). In the present embodiment, lead (Pb) is located at the A site, and zirconium (Zr) and titanium (Ti) are located at the B site.

[0059] The piezoelectric material is not limited to the above-described PZT. Other elements can be contained in the A site or the B site. For example, the piezoelectric material can be barium zirconate titanate (Ba(Zr, Ti)O3), lead lanthanum zirconate titanate ((Pb, La)(Zr, Ti)O3), lead niobium magnesium zirconate titanate (Pb(Zr, Ti)(Mg, Nb)O3), lead niobium zirconate titanate containing silicon (Pb(Zr, Ti, Nb)O3), or the like, which is a perovskite material.

[0060] In addition, the piezoelectric material can be a material in which the amount of Pb is suppressed, i.e., a so-called low-lead material, or a material that does not use Pb, i.e., a so-called non-lead material. If a low-lead material is used as the piezoelectric material, it is possible to reduce the amount of Pb used. In addition, if a non-lead material is used as the piezoelectric material, it is possible to use no Pb. Therefore, by using a low-lead material or a non-lead material as the piezoelectric material, it is possible to reduce the environmental load.

[0061] As a non-lead piezoelectric material, for example, a BFO-based material containing bismuth ferrite (BFO; BiFe03) can be listed. In BFO, bismuth (Bi) is located at an A site, and iron (Fe) is located at a B site. In BFO, other elements can also be added. For example, in BFO, at least one element selected from manganese (Mn), aluminum (Al), lanthanum (La), barium (Ba), titanium (Ti), cobalt (Co), cerium (Ce), samarium (Sm), chromium (Cr), potassium (K), lithium (Li), calcium (Ca), strontium (Sr), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), nickel (Ni), zinc (Zn), praseodymium (Pr), neodymium (Nd), europium (Eu) can also be added.

[0062] Further, as another example of a non-lead piezoelectric material, a KNN-based material containing sodium niobate (KNN; KNaNb03) can be listed. In KNN, other elements can also be added. For example, in KNN, at least one element selected from manganese (Mn), lithium (Li), barium (Ba), calcium (Ca), strontium (Sr), zirconium (Zr), titanium (Ti), bismuth (Bi), tantalum (Ta), antimony (Sb), iron (Fe), cobalt (Co), silver (Ag), magnesium (Mg), zinc (Zn), copper (Cu), vanadium (V), chromium (Cr), molybdenum (Mo), tungsten (W), nickel (Ni), aluminum (Al), silicon (Si), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), and europium (Eu) can also be added.

[0063] In the piezoelectric material, a material having a component with a part of an element missing, a material having a component with a part of an element in excess, and a material having a component with a part of an element substituted with another element are also included. As long as the basic characteristics of the piezoelectric layer 70 are not changed, a material deviating from the stoichiometric composition due to the missing or excess, or a material in which a part of an element is substituted with another element is also included in the piezoelectric material according to the present embodiment. Of course, the piezoelectric material that can be used in the present embodiment is not limited to a material including Pb, Bi, Na, K, and the like as described above.

[0064] As Figure 2-4As shown, the second electrode 80 is continuously disposed on the side of the piezoelectric layer 70 opposite to the first electrode 60, i.e., in the -Z direction, and constitutes a common electrode shared by the plurality of active portions 310. The second electrode 80 is continuously disposed across the +X direction with a predetermined width in the +Y direction. Furthermore, the second electrode 80 is also disposed on the inner surface of the recess 71, i.e., on the side surface of the recess 71 of the piezoelectric layer 70, and on the second vibrating plate 52, which serves as the bottom surface of the recess 71. Of course, the second electrode 80 may be disposed only on a portion of the inner surface of the recess 71, or it may be disposed on the entire surface of the inner surface of the recess 71.

[0065] Furthermore, an independent lead electrode 91 is drawn from the first electrode 60 as a lead wire. Additionally, a common lead electrode 92 is drawn from the second electrode 80 as a lead wire. A flexible wiring board 120 is connected to the ends of these independent lead electrodes 91 and the common lead electrode 92 opposite to the ends connected to the piezoelectric actuator 300. A drive circuit 121 is mounted on the wiring board 120, the drive circuit 121 having switching elements for driving the piezoelectric actuator 300.

[0066] like Figure 1 as well as Figure 3 As shown, a protective substrate 30, approximately the same size as the flow channel forming substrate 10, is joined to the -Z direction side of the flow channel forming substrate 10 on which the piezoelectric actuator 300 is formed. The protective substrate 30 has a space, namely a holding portion 31, for protecting the piezoelectric actuator 300. The holding portion 31 is a component independently provided for each row of piezoelectric actuators 300 arranged side by side in the +X direction, and two are formed side by side in the +Y direction. Furthermore, a through hole 32 extending in the +Z direction is provided on the protective substrate 30 between the two holding portions 31 arranged side by side in the +Y direction. The ends of the individual lead electrodes 91 and the common lead electrodes 92, which are led out from the electrodes of the piezoelectric actuator 300, are provided to be exposed in the through hole 32, and the individual lead electrodes 91 and the common lead electrodes 92 are electrically connected to the wiring substrate 120 in the through hole 32.

[0067] In addition, such as Figure 3As shown, a housing component 40 is fixed to the protective substrate 30. The housing component 40, together with the flow channel forming substrate 10, divides and forms a manifold 100 communicating with a plurality of pressure chambers 12. The housing component 40, when viewed from above, has a shape substantially the same as the aforementioned connecting plate 15. The housing component 40 is engaged with both the protective substrate 30 and the aforementioned connecting plate 15. In this embodiment, the housing component 40 is engaged with the connecting plate 15. Furthermore, although not specifically illustrated, the housing component 40 and the protective substrate 30 are also joined together.

[0068] The housing component 40 has a recess 41 with a depth that accommodates the channel forming substrate 10 and the protective substrate 30 on the protective substrate 30 side. This recess 41 has an opening area larger than the surface of the protective substrate 30 that engages with the channel forming substrate 10. Furthermore, when the channel forming substrate 10 is accommodated in the recess 41, the opening surface of the recess 41 on the nozzle plate 20 side is sealed by the connecting plate 15. Thus, a third manifold portion 42 is formed at the outer periphery of the channel forming substrate 10 by the housing component 40 and the channel forming substrate 10. The manifold 100 of this embodiment is constituted by the first manifold portion 17 and the second manifold portion 18 provided on the connecting plate 15, and the third manifold portion 42 formed by the housing component 40 and the channel forming substrate 10. The manifold 100 is arranged continuously in a direction that spans the pressure chambers 12 side by side, i.e., in the +X direction, and the supply connection channels 19 that connect each pressure chamber 12 and the manifold 100 are arranged side by side in the +X direction.

[0069] Furthermore, a malleable substrate 45 is provided on the +Z side of the openings of the connecting plate 15, which include the first manifold portion 17 and the second manifold portion 18. This malleable substrate 45 seals the openings on the liquid injection surface 20a side of the first manifold portion 17 and the second manifold portion 18. In this embodiment, such a malleable substrate 45 includes a sealing film 46 made of a flexible thin film and a fixing substrate 47 made of a rigid material such as metal. Since the area of ​​the fixing substrate 47 opposite to the manifold 100 becomes an opening 48 that is completely removed in the thickness direction, one side of the manifold 100 becomes a flexible portion, or malleable portion 49, that is sealed only by the flexible sealing film 46.

[0070] As explained above, in the inkjet recording head 1 as one example of the liquid ejection head of the present application, the pressure chamber 12, the vibration plate 50 provided with the first vibration plate 51, the second vibration plate 52, and the third vibration plate 53, and the piezoelectric actuator 300 provided with the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially stacked. Further, in the inkjet recording head 1, a plurality of pressure chambers 12 are provided side by side in the +X direction as the first direction in plan view from the +Z direction as the stacking direction. Further, in the inkjet recording head 1, in the +X direction, among the first vibration plate 51 and the second vibration plate 52, there are the central portion P2 in which the piezoelectric layer 70 and the third vibration plate 53 are stacked, and the edge portion P1 in which the piezoelectric layer 70 and the third vibration plate 53 are not stacked. Further, in the inkjet recording head 1, one of the first vibration plate 51 and the second vibration plate 52 has a compressive stress, and the other has a tensile stress. Also, in the inkjet recording head 1, the Young's modulus of the third vibration plate 53 is greater than the Young's modulus of the first vibration plate 51 and the second vibration plate 52.

[0071] In this way, by providing the central portion P2 in which the first vibration plate 51, the second vibration plate 52, and the third vibration plate 53 are stacked, and the edge portion P1 in which the third vibration plate 53 is not stacked in the vibration plate 50, it is possible to increase the displacement amount of the vibration plate 50, that is, to obtain a larger displacement with a smaller voltage. In particular, by making the Young's modulus of the third vibration plate 53 greater than the Young's modulus of the first vibration plate 51 and the second vibration plate 52, it is possible to increase the displacement amount of the portion of the vibration plate 50 in which the third vibration plate 53 is not provided, and to increase the weight of the ink droplet or to increase the flight speed of the ink droplet.

[0072] Further, since one of the first vibration plate 51 and the second vibration plate 52 has a compressive stress and the other has a tensile stress, stress balance can be achieved at the portion of the vibration plate 50 in which the third vibration plate 53 is not provided, and thus it is possible to suppress the case where the vibration plate 50 is damaged when the vibration plate 50 is displaced.

[0073] Further, by providing the third vibration plate 53 having a Young's modulus larger than those of the first vibration plate 51 and the second vibration plate 52 in the vibration plate 50, it is possible to increase the resonance frequency of the vibration plate 50, increase the driving frequency, and perform continuous ejection of ink droplets in a short time. Generally, since the displacement amount and the resonance frequency become in a trade-off relationship, when a material having a small Young's modulus is used in order to increase the displacement amount of the vibration plate 50, the resonance frequency becomes small. On the contrary, when a material having a large Young's modulus is used in order to increase the resonance frequency of the vibration plate 50, there are cases where the displacement amount of the vibration plate 50 becomes small and the weight of the ejected ink droplets becomes small, or a large voltage needs to be applied to the piezoelectric actuator 300 in order to displace the vibration plate 50. In the present embodiment, by providing a portion where the third vibration plate 53 is formed and a portion where the third vibration plate 53 is not formed, it is possible to increase the displacement amount of the vibration plate 50 and increase the resonance frequency.

[0074] Further, in the inkjet recording head of the present embodiment, it is preferable that the portion where the piezoelectric layer 70 and the third vibration plate 53 are not laminated is a portion corresponding to the edge portion Pl of the pressure chamber 12 in the +X direction as the first direction. Thus, since the rigidity of the portion of the vibration plate 50 opposite to both ends of the pressure chamber 12 in the +X direction and the -X direction, so-called arm portions of the vibration plate 50, is suppressed, the piezoelectric actuator 300 can displace well.

[0075] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that the first vibration plate 51 is composed of a thermal oxidation film, the partition wall 11 partitioning the plurality of pressure chambers 12 is composed of a single crystal silicon, and the first vibration plate 51 and the partition wall 11 are in contact. By composing the first vibration plate 51 in contact with the partition wall 11 composed of a single crystal silicon in this way by a thermal oxidation film, it is possible to improve the adhesion of the partition wall 11 and the first vibration plate 51, thereby suppressing the occurrence of peeling and the like.

[0076] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that, on the inner wall of the pressure chamber 12, the flow channel protection film 13 is formed, and the Young's modulus of the flow channel protection film 13 is smaller than that of the third vibration plate 53. By making the Young's modulus of the flow channel protection film 13 smaller than that of the third vibration plate 53 in this way, it is possible to suppress the case where the displacement of the vibration plate 50 is significantly reduced due to the flow channel protection film 13.

[0077] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that the piezoelectric layer 70 contain lead, the third vibration plate 53 be an oxide containing zirconium, a nitride containing silicon, or an acid nitride containing silicon, and at least one of the first vibration plate 51 and the second vibration plate 52 contain silicon oxide or silicon. In this way, by providing the third vibration plate 53 of the oxide containing zirconium, the nitride containing silicon, or the acid nitride containing silicon between the piezoelectric layer 70 and the second vibration plate 52, it is possible to suppress the diffusion of the lead contained in the piezoelectric layer 70 to the side of the second vibration plate 52 as compared with the third vibration plate 53. Further, since the piezoelectric layer 70 is not formed in the edge portion P1 which is the portion where the third vibration plate 53 is not formed, it is possible to suppress the diffusion of the lead contained in the piezoelectric layer 70 to the second vibration plate 52 and the first vibration plate 51.

[0078] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that at least one of the first vibration plate 51 and the second vibration plate 52 be amorphous. By making the first vibration plate 51 and the second vibration plate 52 amorphous, it is possible to make the vibration plate 50 easily displace, and thus it is difficult to generate cracks.

[0079] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that the first vibration plate 51 have a compressive stress and the second vibration plate 52 have a tensile stress. In this way, by making the first vibration plate 51 have a compressive stress and the second vibration plate 52 have a tensile stress, it is possible to make the vibration plate 50 easily displace convexly to the side of the pressure chamber 12 and make the displacement amount large. Therefore, it is possible to increase the weight of the ink droplet ejected from the nozzle 21 or accelerate the flight speed of the ink droplet.

[0080] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that the thickness d1 of the first vibration plate 51 be larger than the thickness d2 of the second vibration plate 52. This is to say, in general, a compressive stress film is easily displaced as compared with a tensile stress film. Therefore, by making the thickness d1 of the first vibration plate 51 having a compressive stress thicker than the thickness d2 of the second vibration plate 52 having a tensile stress, it is possible to further increase the displacement of the vibration plate 50.

[0081] Further, in the inkjet recording head 1 of the present embodiment, it is preferable that the first vibration plate 51 have a tensile stress and the second vibration plate 52 have a compressive stress. In this way, by making the first vibration plate 51 have a tensile stress and the second vibration plate 52 have a compressive stress, it is possible to make the vibration plate 50 displace convexly to the -Z direction which is the side opposite to the side of the pressure chamber 12 and make the displacement amount large. Therefore, it is possible to make the ink droplet ejected from the nozzle 21 easily tear off from the meniscus.

[0082] Furthermore, in the inkjet recording head 1 of this embodiment, it is preferable that the thickness d2 of the second diaphragm 52 is greater than the thickness d1 of the first diaphragm 51. This means that, generally speaking, a compressive stress membrane is easier to displace than a tensile stress membrane. Therefore, by making the thickness d2 of the second diaphragm 52, which has compressive stress, greater than the thickness d1 of the first diaphragm 51, which has tensile stress, the displacement of the diaphragm 50 can be further increased.

[0083] Implementation Method 2

[0084] Figure 7 This is a cross-sectional view of the main part of an inkjet recording head, which is an example of a liquid jetting head according to Embodiment 2 of the present invention. Furthermore, the same reference numerals are used for the same parts as in the embodiments described above, and repeated descriptions are omitted.

[0085] like Figure 7 As shown, the recess 71 is formed to a depth that reaches the midpoint of the +Z direction, which is the thickness direction of the second vibrating plate 52. That is, a portion of the second vibrating plate 52 is formed in a residual manner on the bottom surface of the recess 71 in the +Z direction. In other words, a portion of the thickness direction of the first vibrating plate 51 and the second vibrating plate 52 is formed on the bottom surface of the recess 71.

[0086] Such a recess 71 and a vibrating plate 50 can be formed, for example, by using excessive etching to simultaneously remove a portion of the second vibrating plate 52 when forming the piezoelectric layer 70 and the third vibrating plate 53 by etching.

[0087] Even with this structure, similar to Embodiment 1 described above, by providing a central portion P2 in the vibrating plate 50 where the first vibrating plate 51, the second vibrating plate 52, and the third vibrating plate 53 are stacked, and an edge portion P1 where the third vibrating plate 53 is not stacked, the displacement of the vibrating plate 50 is increased, that is, a larger displacement is obtained with a smaller voltage. In particular, by making the Young's modulus of the third vibrating plate 53 greater than that of the first vibrating plate 51 and the second vibrating plate 52, the displacement of the portion of the vibrating plate 50 where the third vibrating plate 53 is not provided can be increased, and the weight of the ink droplets or the flight speed of the ink droplets can be increased.

[0088] Furthermore, since one of the first vibrating plate 51 and the second vibrating plate 52 has compressive stress and the other has tensile stress, stress balance can be achieved in the part of the vibrating plate 50 where the third vibrating plate 53 is not provided, and the situation where the vibrating plate 50 is damaged when it is displaced can be suppressed.

[0089] Further, by providing the third vibration plate 53 having a Young's modulus larger than that of the first vibration plate 51 and the second vibration plate 52 in the vibration plate 50, it is possible to increase the resonance frequency of the vibration plate 50, increase the driving frequency, and perform continuous ejection of ink droplets in a short time. Since the displacement amount and the resonance frequency are generally in a trade-off relationship, when a material having a small Young's modulus is used in order to increase the displacement amount of the vibration plate 50, the resonance frequency becomes small. On the contrary, when a material having a large Young's modulus is used in order to increase the resonance frequency of the vibration plate 50, there is a case where the displacement amount of the vibration plate 50 becomes small and the weight of the ejected ink droplets becomes small, or a large voltage needs to be applied to the piezoelectric actuator 300 in order to displace the vibration plate 50. In the present embodiment, by providing the portion where the third vibration plate 53 is formed and the portion where the third vibration plate 53 is not formed, it is possible to increase the displacement amount of the vibration plate 50 and increase the resonance frequency.

[0090] Further, in the inkjet recording head 1 of the present embodiment, at least one of the first vibration plate 51 and the second vibration plate 52 is thinned at the edge portion PI where the piezoelectric layer 70 and the third vibration plate 53 are not laminated, compared to the central portion P2 where the piezoelectric layer 70 and the third vibration plate 53 are laminated.

[0091] In this way, by thinning the thickness of at least one of the first vibration plate 51 and the second vibration plate 52 at the edge portion PI where the third vibration plate 53 and the piezoelectric layer 70 are not formed, it is possible to further increase the displacement amount of the vibration plate 50. Note that, although in the present embodiment, the thickness of the second vibration plate 52 is thinned at the edge portion PI, it is not particularly limited thereto, and it can be configured such that the thickness of the first vibration plate 51 is thinner than that of the central portion P2 at the edge portion PI.

[0092] Embodiment 3

[0093] Figure 8 A plan view of a main portion of an inkjet recording head which is an example of a liquid ejecting head according to Embodiment 3 of the present application. Figure 9 A plan view of a main portion of an inkjet recording head which is an example of a liquid ejecting head according to Embodiment 3 of the present application. Figure 8 A cross-sectional view taken along line C-C' of FIG. 17. Note that the same reference numerals are given to the same components as those of the above-described embodiments, and overlapping description is omitted.

[0094] As shown in the drawing, in the flow channel forming substrate 10, a plurality of pressure chambers 12 are provided side by side along the X direction. The shape of the pressure chamber 12 when viewed in the +Z direction, that is, the opening shape in the +Z direction, is a so-called rounded rectangular shape (also called a racetrack shape) in which a rectangular shape with the +Y direction as the long side direction is taken as a base and both end portions in the long side direction are provided in a semicircular shape. That is, the pressure chamber 12 has an elongated shape in which the +Y direction is the long side direction and the +X direction is the short side direction when viewed in the +Z direction. Of course, the shape of the pressure chamber 12 when viewed in the +Z direction is not particularly limited as in Embodiment 1 described above.

[0095] On the -Z direction side of the flow channel forming substrate 10, a vibration plate 50 and a piezoelectric actuator 300 are formed.

[0096] In the vibration plate 50, a first vibration plate 51, a second vibration plate 52, and a third vibration plate 53 are stacked in this order toward the -Z direction.

[0097] The active portion 310 of the piezoelectric actuator 300 is provided at the edge portion P1 of the flexible region P of the vibration plate 50. Moreover, the active portion 310 is provided to the outside of the edge portion P1, that is, to the outside of the pressure chamber 12. Moreover, the active portion 310 is not provided at the central portion P2.

[0098] Moreover, the third vibration plate 53 and the piezoelectric layer 70 are provided to the region in which the active portion 310 is provided, that is, the edge portion P1 and the outside of the edge portion P1, that is, the outside of the pressure chamber 12. In addition, the third vibration plate 53 and the piezoelectric layer 70 are not provided at the central portion P2. That is, the central portion P2 is a region in which the third vibration plate 53 and the piezoelectric layer 70 are not formed.

[0099] Even with such a structure, as in the above-described embodiments, by providing the edge portion P1 in which the first vibration plate 51, the second vibration plate 52, and the third vibration plate 53 are stacked and the central portion P2 in which the third vibration plate 53 is not stacked in the vibration plate 50, it is possible to increase the displacement amount of the vibration plate 50, that is, to obtain a larger displacement with a smaller voltage. In particular, by making the Young's modulus of the third vibration plate 53 larger than the Young's modulus of the first vibration plate 51 and the second vibration plate 52, it is possible to increase the displacement amount of the portion of the vibration plate 50 in which the third vibration plate 53 is not provided, that is, the central portion P2, and to increase the weight of the ink droplet or to increase the flight speed of the ink droplet.

[0100] Further, since one of the first vibrating plate 51 and the second vibrating plate 52 has a compressive stress and the other has a tensile stress, stress balance can be achieved at the portion of the vibrating plate 50 where the third vibrating plate 53 is not provided, and thus, the vibrating plate 50 can be prevented from being damaged when the vibrating plate 50 is displaced.

[0101] Further, by providing the third vibrating plate 53 having a larger Young's modulus than the first vibrating plate 51 and the second vibrating plate 52 in the vibrating plate 50, the resonance frequency of the vibrating plate 50 can be increased, the driving frequency can be increased, and continuous ejection of ink droplets can be performed in a short time. Since the displacement amount and the resonance frequency are generally in a trade-off relationship, when a material having a small Young's modulus is used in order to increase the displacement amount of the vibrating plate 50, the resonance frequency becomes small. In contrast, when a material having a large Young's modulus is used in order to increase the resonance frequency of the vibrating plate 50, there is a case where the displacement amount of the vibrating plate 50 becomes small and the weight of the ejected ink droplets becomes small, or a large voltage needs to be applied to the piezoelectric actuator 300 in order to displace the vibrating plate 50. In the present embodiment, by providing the portion where the third vibrating plate 53 is formed and the portion where the third vibrating plate 53 is not formed, the displacement amount of the vibrating plate 50 can be increased and the resonance frequency can be increased.

[0102] Further, in the inkjet recording head 1 of the present embodiment, the portion where the piezoelectric layer 70 and the third vibrating plate 53 are not laminated is the central portion P2 corresponding to the center of the pressure chamber 12 in the +X direction as the first direction.

[0103] Other Embodiments

[0104] Although the above describes each of the embodiments of the present application, the basic structure of the present application is not limited to the above-described structure.

[0105] For example, although in the above-described Embodiment 1, the first electrode 60 is provided as an independent electrode independent for each active portion 310, and the second electrode 80 is provided as a common electrode common to the plurality of active portions 310, the present application is not limited thereto.

[0106] Further, although in each of the above-described embodiments, a configuration is provided in which, in the +X direction within the flexible region P, a portion provided with the third vibrating plate 53 and the piezoelectric layer 70 with respect to the first vibrating plate 51 and the second vibrating plate 52 and a portion not provided with the third vibrating plate 53 and the piezoelectric layer 70 are provided, in addition to this, a configuration can also be provided in which, for example, even in the +Y direction within the flexible region P, a portion provided with the third vibrating plate 53 and the piezoelectric layer 70 with respect to the first vibrating plate 51 and the second vibrating plate 52 and a portion not provided with the third vibrating plate 53 and the piezoelectric layer 70 are provided similarly. In the recording head 1 of Embodiments 1 and 2, for example, a configuration can be provided in which the third vibrating plate 53 and the piezoelectric layer 70 are not provided at both ends in the direction along the Y axis, that is, the +Y direction end and the -Y direction end, and are provided at the central portion. Further, in the recording head of Embodiment 3, a configuration can be provided in which, for example, the third vibrating plate 53 and the piezoelectric layer 70 are provided at the +Y direction end and the -Y direction end, and are not provided at the central portion. Of course, the portion provided with the third vibrating plate 53 and the piezoelectric layer 70 and the portion not provided with them in the direction along the Y axis are not limited to this.

[0107] Further, the recording head 1 of each of the embodiments is mounted on an inkjet recording device as one example of a liquid ejecting device. Figure 10 FIG. 1 is a schematic view showing one example of an inkjet recording device as one example of a liquid ejecting device according to one embodiment.

[0108] In Figure 10 In the inkjet recording device I shown in FIG. 1, the recording head 1 is provided on a cartridge 2 that constitutes an ink supply unit in a detachable manner, and is mounted on a carriage 3. The carriage 3 on which the recording head 1 is mounted is provided in a movable manner in the axial direction of a carriage shaft 5 that is installed on a device main body 4.

[0109] Further, by causing the driving force of a driving motor 6 to be transmitted to the carriage 3 via a plurality of gears and a synchronous toothed belt 7 that are not shown, the carriage 3 on which the recording head 1 is mounted is caused to move along the carriage shaft 5. On the other hand, a conveyance roller 8 as a conveyance unit is provided on the device main body 4, and a recording sheet S as a recording medium such as paper is conveyed by the conveyance roller 8. In addition, the conveyance unit that conveys the recording sheet S is not limited to the conveyance roller, and can be a belt or a roller, or the like.

[0110] In such an inkjet recording apparatus I, while the recording sheet S is transported in the +X direction with respect to the recording head 1 and the carriage 3 is reciprocated in the Y direction with respect to the recording sheet S, the ejection of ink droplets, so-called printing, is performed by ejecting ink droplets from the recording head 1 across substantially the entire face of the recording sheet S.

[0111] Further, although in the above-described inkjet recording apparatus I, an apparatus in which the recording head 1 is mounted on the carriage 3 and is reciprocated in the Y direction as the main scanning direction is exemplified, the present application is not particularly limited thereto, and can be applied, for example, to a so-called line-type recording apparatus in which the recording head 1 is fixed and a recording sheet S of paper or the like is moved only in the X direction as the sub-scanning direction to perform printing.

[0112] Further, although in the above-described embodiments, an inkjet recording head is exemplified as one example of a liquid ejection head, and an inkjet recording apparatus is exemplified as one example of a liquid ejection apparatus, the present application is an application that broadly targets all liquid ejection heads and liquid ejection apparatuses, and can obviously be applied to a liquid ejection head or a liquid ejection apparatus that ejects a liquid other than ink. As other liquid ejection heads, for example, various recording heads used in image recording apparatuses such as printers, color material ejection heads used in the manufacture of color filters for liquid crystal displays or the like, electrode material ejection heads used in the formation of electrodes for organic EL (Electro Luminescence) displays, FEDs (Flat Emission Displays), or the like, biological organic matter ejection heads used in the manufacture of biochips, or the like can be exemplified, and can be applied to a liquid ejection apparatus that has the relevant liquid ejection head.

[0113] Explanation of Symbols

[0114] I… Inkjet recording apparatus (liquid ejection apparatus); 1… Inkjet recording head (liquid ejection head); 2… Cartridge; 3… Carriage; 4… Apparatus main body; 5… Carriage shaft; 6… Driving motor; 7… Synchronous toothed belt; 8… Conveyance roller; 10… Flow channel forming substrate; 11… Partition wall; 12… Pressure chamber; 13… Flow channel protection film; 15… Communication plate; 16… Nozzle communication passage; 17… First manifold portion; 18… Second manifold portion; 19… Supply communication passage; 20… Nozzle plate; 20a… Liquid ejection surface; 21… Nozzle; 30… Protection substrate; 31… Holding portion; 32… Through-hole; 40… Casing member; 41… Concave portion; 42… Third manifold portion; 43… Connection port; 44… Guide inlet; 45… Plasticity substrate; 46… Sealing film; 47… Fixed substrate; 48… Open portion; 49… Plasticity portion; 50… Vibration plate; 51… First vibration plate; 52… Second vibration plate; 53… Third vibration plate; 60… First electrode; 70… Piezoelectric body layer; 71… Concave portion; 80… Second electrode; 91… Independent lead electrode; 92… Common lead electrode; 100… Manifold; 120… Wiring substrate; 121… Driving circuit; 300… Piezoelectric actuator; 310… Active portion; P… Flexible region; P1… Edge portion; P2… Central portion; S… Recording sheet.

Claims

1. A liquid injection head, characterized in that, It is a liquid jet head consisting of a pressure chamber, a vibrating plate having a first vibrating plate, a second vibrating plate, and a third vibrating plate, and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode stacked sequentially. In a top-view observation from the stacking direction of the vibrating plate and the piezoelectric actuator, multiple pressure chambers are arranged side by side in the first direction. A first portion consisting of the first vibrating plate, the second vibrating plate, the third vibrating plate, and the piezoelectric layer, and a second portion consisting of the first vibrating plate and the second vibrating plate but without the piezoelectric layer and the third vibrating plate, are disposed in the first direction. One of the first and second vibrating plates has compressive stress, and the other has tensile stress. The Young's modulus of the third vibrating plate is greater than that of the first and second vibrating plates. The second part is the portion corresponding to both ends of the pressure chamber in the first direction. In the first direction, the width of the first electrode is shorter than the width of the piezoelectric layer and the width of the third vibrating plate.

2. The liquid injection head as described in claim 1, characterized in that, The first part comprises a portion consisting of the first vibrating plate, the second vibrating plate, the third vibrating plate, the piezoelectric layer, and the second electrode stacked together. The second part is the portion where the first vibrating plate, the second vibrating plate, and the second electrode are stacked without the piezoelectric layer and the third vibrating plate.

3. The liquid injection head as described in claim 1 or claim 2, characterized in that, The first vibrating plate is made of a thermally oxidized film, and the partitions separating the multiple pressure chambers are made of monocrystalline silicon. The first vibrating plate is in contact with the partition wall.

4. The liquid injection head as described in claim 1, characterized in that, A flow channel protective film is formed on the inner wall of the pressure chamber. The Young's modulus of the flow channel protective film is less than that of the Young's modulus of the third vibrating plate.

5. The liquid injection head as described in claim 1, characterized in that, The piezoelectric layer contains lead, the third vibrating plate is an oxide containing zirconium, a nitride containing silicon, or an acidic nitride containing silicon, and at least one of the first and second vibrating plates contains silicon oxide or silicon.

6. The liquid injection head as described in claim 1, characterized in that, At least one of the first vibrating plate and the second vibrating plate is amorphous.

7. The liquid injection head as claimed in claim 1, characterized in that, The first vibrating plate has compressive stress. The second vibrating plate has tensile stress.

8. The liquid injection head as described in claim 7, characterized in that, The thickness of the first vibrating plate is greater than the thickness of the second vibrating plate.

9. The liquid injection head as claimed in claim 1, characterized in that, The first vibrating plate has tensile stress. The second vibrating plate has compressive stress.

10. The liquid injection head as described in claim 9, characterized in that, The thickness of the second vibrating plate is greater than the thickness of the first vibrating plate.

11. The liquid injection head as claimed in claim 1, characterized in that, Compared to the first portion, at least one of the first and second vibrating plates is thinner in the second portion.

12. A liquid injection device, characterized in that, It has a liquid injection head as described in any one of claims 1 to 11.

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