Liquid ejection head and liquid ejection device

Abstract

The present invention provides a liquid ejection head and a liquid ejection device for suppressing cracks in a piezoelectric body or a vibration plate. The liquid ejection head comprises: a plurality of piezoelectric bodies; independent electrodes independently arranged relative to the plurality of piezoelectric bodies; a common electrode commonly arranged relative to the plurality of piezoelectric bodies; and a vibration plate, which electrically drives the piezoelectric body to vibrate via the independent electrodes and the common electrodes. The piezoelectric body, the independent electrodes, the common electrode, and the vibration plate are stacked along a stacking direction, and when the portion of the piezoelectric body sandwiched by the independent electrodes and the common electrodes in the stacking direction is set as an active portion, and the portion not sandwiched by the independent electrodes and the common electrodes is set as a passive portion, when the piezoelectric body is observed along the stacking direction and includes the end of the active portion in the extension direction of the independent electrodes and the boundary of the passive portion as a first region, and the region of the piezoelectric body different from the first region is set as a second region, the thickness of the piezoelectric body in the first region is thicker than the thickness of the piezoelectric body in the second region.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection device. Background Art

[0002] Regarding a liquid ejection head, a liquid ejection head having a piezoelectric element having a piezoelectric layer provided on an independent electrode and a common electrode provided on the piezoelectric layer is disclosed in Patent Document 1. The liquid ejection head is provided in a liquid ejection device such as a printer, and ejects liquid such as ink by utilizing displacement of a piezoelectric body generated by applying a voltage.

[0003] In the liquid ejection head as disclosed in Patent Document 1, when voltage is applied, a displacement difference occurs between an active portion sandwiched by a common electrode and an independent electrode and a passive portion not sandwiched by the common electrode and the independent electrode in the piezoelectric layer. Therefore, stress due to the displacement difference may occur at the boundary between the active portion and the passive portion, and cracks may occur in the piezoelectric element.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-58467 Summary of the invention

[0005] According to a first aspect of the present disclosure, there is provided a liquid ejection head, which includes: a plurality of piezoelectric bodies; independent electrodes independently provided with respect to the plurality of piezoelectric bodies; a common electrode commonly provided with respect to the plurality of piezoelectric bodies; and a vibration plate that vibrates by electrically driving the piezoelectric bodies via the independent electrodes and the common electrode. In the liquid ejection head, the piezoelectric bodies, the independent electrodes, the common electrode, and the vibration plate are stacked in a stacking direction, and when a portion of the piezoelectric body sandwiched by the independent electrodes and the common electrode in the stacking direction is set as an active portion, a portion of the piezoelectric body not sandwiched by the independent electrodes and the common electrode in the stacking direction is set as a passive portion, and a region of the piezoelectric body including an end of the active portion in the extending direction of the independent electrodes and a boundary of the passive portion when viewed along the stacking direction is set as a first region, and a region of the piezoelectric body different from the first region is set as a second region, the thickness of the piezoelectric body in the first region is thicker than the thickness of the piezoelectric body in the second region.

[0006] According to a second aspect of the present disclosure, there is provided a liquid ejection device including: the liquid ejection head according to the first aspect; and a control unit that controls an ejection operation from the liquid ejection head. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1It is an explanatory diagram showing a schematic structure of a liquid ejecting device including a liquid ejecting head as a first embodiment.

[0008] Figure 2 It is an exploded perspective view showing the structure of the liquid ejecting head according to the present embodiment.

[0009] Figure 3 It is a schematic diagram showing a cross section of a main part of the liquid ejecting head along the YZ plane.

[0010] Figure 4 A diagram for explaining a schematic structure of a piezoelectric portion.

[0011] Figure 5 for Figure 4 VV cross-sectional view of the pressure chamber and the piezoelectric part.

[0012] Figure 6 It is a diagram for explaining a schematic structure of a piezoelectric portion in the second embodiment.

[0013] Figure 7 for Figure 6 VII-VII cross-sectional view of the piezoelectric portion in FIG.

[0014] Figure 8 It is a diagram showing a cross section of a pressure chamber and a piezoelectric portion along an XZ plane in the third embodiment. DETAILED DESCRIPTION

[0015] A. First Implementation Method:

[0016] Figure 1 1 is an explanatory diagram showing a schematic structure of a liquid ejection device 100 including a liquid ejection head 200 according to a first embodiment. Figure 1 In the figure, arrow marks along mutually orthogonal X, Y, and Z directions are shown. The X, Y, and Z directions are directions along the X-axis, Y-axis, and Z-axis which are three mutually orthogonal spatial axes, and include directions along one side of the X-axis, Y-axis, and Z-axis, and opposite directions thereof, respectively. Specifically, the positive directions along the X-axis, Y-axis, and Z-axis are +X direction, +Y direction, and +Z direction, respectively, and the negative directions along the X-axis, Y-axis, and Z-axis are -X direction, -Y direction, and -Z direction, respectively. Sometimes, the plane along the X and Y directions is called the XY plane, the plane along the X and Z directions is called the XZ plane, and the plane along the Y and Z directions is called the YZ plane. In addition, in Figure 1 In the embodiment, the X-axis and the Y-axis are axes along the horizontal plane, and the Z-axis is an axis along the vertical line. Therefore, in this embodiment, the -Z direction is the gravity direction. In other figures, arrow marks along the X, Y, and Z directions are appropriately shown. Figure 1The X, Y, and Z directions in the figure and the X, Y, and Z directions in other figures represent the same directions. In addition, in this specification, orthogonal includes a range of 90°±10°.

[0017] The liquid ejection device 100 of the present embodiment is an inkjet printer that prints an image on a print medium P by ejecting ink as a liquid. The liquid ejection device 100 ejects ink on a print medium P such as paper based on print data indicating the formation (ON) or non-formation (OFF) of dots in the print medium P, thereby forming dots at various positions on the print medium P, thereby printing an image on the print medium P. In addition, as the print medium P, for example, plastic, film, fiber, cloth, leather, metal, glass, wood, ceramics, and other materials that can hold liquids can be used in addition to paper. In addition, as the liquid of the liquid ejection device 100, in addition to ink, various color materials, electrode materials, samples such as biological organic matter or inorganic matter, lubricating oil, resin liquid, etching liquid, and other arbitrary liquids can be used.

[0018] The liquid ejection device 100 includes a liquid ejection head 200 , a carriage 40 , a drive motor 46 that drives the carriage 40 , a transport motor 51 that transports the printing medium P, an ink cartridge 80 , and a control unit 110 .

[0019] The control unit 110 is composed of a computer having one or more processors, a main storage device, and an input / output interface for inputting and outputting signals to and from the outside. The control unit 110 controls each mechanism of the liquid ejection device 100 according to the printing data, thereby ejecting ink from the liquid ejection head 200 onto the printing medium P and printing an image on the printing medium P. That is, the control unit 110 controls the ejection operation of the liquid ejection head 200 to eject liquid.

[0020] The ink cartridge 80 stores ink as liquid supplied to the liquid ejection head 200. In the present embodiment, the four ink cartridges 80 are configured to be detachable relative to the carriage 40, and four types of inks having different colors are stored in the four ink cartridges 80 as liquids. In addition, the ink cartridge 80 may be installed on the main body of the liquid ejection device 100 instead of being installed on the carriage 40. In other embodiments, the mechanism for storing ink may be, for example, an ink tank or a bag-shaped liquid bag formed of a flexible film, and the type or number of the mechanism for storing ink and the type or number of the stored ink are not particularly limited.

[0021] The liquid ejection head 200 of this embodiment is held on the carriage 40, and reciprocates in the main scanning direction together with the carriage 40 by the driving force transmitted to the carriage 40 from the driving motor 46 via the driving belt 47. While reciprocating along the main scanning direction, the liquid ejection head 200 ejects the ink supplied from the ink cartridge 80 in the form of droplets to the printing medium P that is transported along the sub-scanning direction intersecting the main scanning direction by the transport motor 51 and the roller not shown. In this embodiment, the main scanning direction is the direction along the X direction. The sub-scanning direction is the direction along the Y direction and is orthogonal to the main scanning direction. In other embodiments, the main scanning direction and the sub-scanning direction may not be orthogonal to each other. The liquid ejection head 200 is electrically connected to the control unit 110 via the flexible cable 41. In addition, the details of the liquid ejection head 200 will be described later. In addition, the liquid ejection device 100 may also have more than two liquid ejection heads 200.

[0022] Figure 2 2 is an exploded perspective view showing the structure of the liquid ejection head 200 of the present embodiment. The liquid ejection head 200 of the present embodiment is constructed by stacking a nozzle plate 210, a pressure chamber substrate 220, a piezoelectric portion 230, and a sealing portion 250 in the Z direction. In addition, a driving circuit 90 is provided on the surface of the sealing portion 250 on the +Z direction side.

[0023] The nozzle plate 210 of the present embodiment is a thin plate-shaped component and is arranged along the XY plane. On the nozzle plate 210, a large number of nozzles 211 are formed in a row along the X-axis direction. The liquid ejection head 200 ejects liquid from the nozzle 211. In the present embodiment, the nozzle plate 210 is formed of stainless steel (SUS). In addition, the nozzle plate 210 may not be limited to stainless steel, for example, it may be formed by other types of metals such as nickel (Ni) alloy, or resin materials such as polyimide or dry film resist, single crystal silicon (Si) substrate or inorganic materials such as glass ceramics. In addition, in other embodiments, more than two rows of nozzles 211 may be formed on the nozzle plate 210.

[0024] The pressure chamber substrate 220 is a plate-shaped component that divides the pressure chamber 221. The pressure chamber substrate 220 is bonded to the surface of the nozzle plate 210 in the +Z direction via, for example, an adhesive or a heat-welded film. In the pressure chamber substrate 220, a hole HL is formed that penetrates the pressure chamber substrate 220 in the Z direction for forming the pressure chamber 221, the ink supply channel 223, and the connecting portion 225. In addition, for example, a part or all of the hole HL may be formed after the vibration plate 231 is stacked on the pressure chamber substrate 220. In the present embodiment, the pressure chamber substrate 220 is formed of a single crystal silicon substrate. In other embodiments, the pressure chamber substrate 220 may be a substrate formed of, for example, other materials having Si as a main component, or other ceramic materials, glass materials, etc.

[0025] In this embodiment, a plurality of pressure chambers 221 are formed so as to be arranged side by side along the X direction. By stacking the pressure chamber substrate 220 on the nozzle plate 210, the plurality of pressure chambers 221 are respectively connected to the nozzle 211. Each pressure chamber 221 has a substantially parallelogram shape with the Y direction as the long side direction when viewed from the Z direction.

[0026] The communication portion 225 is a hollow portion shared by each of the plurality of pressure chambers 221. The communication portion 225 communicates with each of the plurality of pressure chambers 221 via the ink supply channel 223. The ink supply channel 223 is formed to have a narrower width than the pressure chamber 221, and acts as a flow path resistance to the ink flowing from the communication portion 225 into the pressure chamber 221.

[0027] The piezoelectric part 230 is formed by stacking a vibration plate 231 and a piezoelectric element 240 on a pressure chamber substrate 220. The piezoelectric part 230 can vibrate the vibration plate 231 disposed between the piezoelectric element 240 and the pressure chamber substrate 220 by deformation of the piezoelectric element 240, thereby changing the volume of the pressure chamber 221. In addition, the piezoelectric part 230 is sometimes referred to as an actuator. In addition, the details of the piezoelectric part 230 and the piezoelectric element 240 will be described later.

[0028] The sealing portion 250 is bonded to the piezoelectric portion 230 via an adhesive. The sealing portion 250 includes a piezoelectric element holding portion 251 for holding the piezoelectric element 240, and a manifold portion 252 connected to the connecting portion 225 of the pressure chamber substrate 220. In the present embodiment, the sealing portion 250 is formed using a single crystal silicon substrate. In addition, the sealing portion 250 may also be formed using other ceramic materials or glass materials. In this case, it is preferred that the sealing portion 250 is formed using a material having a thermal expansion coefficient substantially the same as that of the pressure chamber substrate 220.

[0029] The driving circuit 90 supplies a driving signal for driving the piezoelectric element 240 to the piezoelectric element 240. As the driving circuit 90, for example, a circuit substrate or a semiconductor integrated circuit (IC) can be used. The driving circuit 90 and the piezoelectric element 240 are electrically connected via the lead electrode 295 and the electrical wiring (not shown). In addition, the driving circuit 90 and the control unit 110 are electrically connected via the electrical wiring (not shown).

[0030] Figure 3 2 is a schematic diagram showing a cross section of a main part of the liquid ejection head 200 along the YZ plane. Figure 3 As shown, by stacking the above-mentioned components, the manifold portion 252 and the communication portion 225 are connected to form a manifold 293 that is a common liquid chamber for each of the plurality of pressure chambers 221. In addition, the nozzle 211, the pressure chamber 221, the ink supply channel 223, and the manifold 293 are connected to form a flow path of the ink. The liquid ejection head 200 changes the volume of the pressure chamber 221 through the piezoelectric portion 230, so that the liquid supplied to the pressure chamber 221 through the above-mentioned flow path is ejected from the nozzle 211. In addition, the manifold 293 is sometimes referred to as a common liquid chamber or a liquid reservoir.

[0031] Figure 4 2 is a diagram for explaining the schematic structure of the piezoelectric portion 230. Figure 4 In FIG. 1 , the portion where the pressure chamber 221 is formed on the XY plane is indicated by a dotted line. Figure 4 In FIG. 1 , a portion where various components constituting a piezoelectric element 240 described later are arranged is also shown on the XY plane.

[0032] Figure 5 for Figure 4 VV cross-sectional view of the pressure chamber 221 and the piezoelectric part 230 in FIG. As described above, the piezoelectric part 230 includes a vibration plate 231 and a piezoelectric element 240. The piezoelectric element 240 includes a plurality of piezoelectric bodies 260, a common electrode 270, and a plurality of independent electrodes 280. The vibration plate 231, the piezoelectric body 260, the common electrode 270, and the independent electrode 280 are stacked in the stacking direction. Specifically, in the present embodiment, these components are stacked in the order of the common electrode 270, the piezoelectric body 260, the independent electrode 280, and the vibration plate 231 along the stacking direction from the +Z direction. The stacking direction includes two directions, a direction along one side of the same axis and an opposite direction thereof. In the present embodiment, it is a direction along the Z direction. The positive and negative directions of the stacking direction are consistent with the positive and negative directions of the Z direction.

[0033] As described above, the vibration plate 231 is configured to vibrate by deformation of the piezoelectric element 240. Specifically, the vibration plate 231 vibrates by electrically driving the piezoelectric body 260 via the independent electrode 280 and the common electrode 270. Figure 5 As shown in FIG. 1 , the vibration plate 231 of the present embodiment includes an elastic layer 232 and an insulating layer 233 located closer to the piezoelectric body 260 than the elastic layer 232 in the Z direction. The elastic layer 232 is formed on the pressure chamber substrate 220 and the pressure chamber 221, and the insulating layer 233 is formed on the elastic layer 232. In the present embodiment, the elastic layer 232 is an elastic film formed of silicon dioxide, and the insulating layer 233 is an insulating film formed of zirconium oxide.

[0034] In the present embodiment, the piezoelectric body 260 is formed of lead zirconate titanate (PZT). In addition, the piezoelectric body 260 may be formed of other types of ceramic materials having a so-called perovskite structure represented by the ABO3 type instead of PZT, for example, barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, sodium tantalate, zinc oxide, barium strontium titanate (BST), strontium bismuth tantalate (SBT), lead metaniobate, lead zinc niobate, scandium lead niobate, etc. In addition, the piezoelectric body 260 is not limited to ceramic materials, and may also be formed of any material having a piezoelectric effect, such as polyvinylidene fluoride and crystal.

[0035] The common electrode 270 refers to an electrode commonly provided with respect to a plurality of piezoelectric bodies 260. The common electrode 270 of the present embodiment is stacked on the upper part of the piezoelectric body 260, and is sometimes referred to as an upper electrode. The independent electrode 280 refers to an electrode independently provided with respect to a plurality of piezoelectric bodies 260. The independent electrode 280 of the present embodiment is stacked on the lower part of the piezoelectric body 260, and is sometimes referred to as a lower electrode. The common electrode 270 or the independent electrode 280 is formed, for example, by various metals such as platinum, iridium, titanium, tungsten, tantalum, or conductive metal oxides such as lanthanum nickelate (LaNiO3).

[0036] like Figure 4 As shown, each of the independent electrodes 280 has the Y direction as its long side direction and extends along the Y direction. Sometimes the direction in which the independent electrode 280 extends is also referred to as the extension direction. The extension direction includes two directions, a direction along one side of the same axis and its opposite direction. In the present embodiment, the positive and negative directions of the extension direction are consistent with the positive and negative directions of the Y direction. In addition, a plurality of independent electrodes 280 are arranged along an arrangement direction orthogonal to the Y direction as the extension direction. The arrangement direction includes two directions, a direction along one side of the same axis and its opposite direction. In the present embodiment, it is a direction along the X direction. The positive and negative directions of the arrangement direction are consistent with the positive and negative directions of the X direction.

[0037] exist Figure 4In FIG. 1 , the outer edge of the portion of the piezoelectric element 240 where the piezoelectric body 260 is provided on the XY plane is indicated by a single-dot chain line. Figure 4 As shown in FIG. 1 , the piezoelectric bodies 260 correspond to the independent electrodes 280 and extend along the Y direction as the extension direction. In addition, the plurality of piezoelectric bodies 260 correspond to the independent electrodes 280 and are arranged along the X direction as the arrangement direction. In addition, the piezoelectric bodies 260 are arranged with gaps Gp between them when viewed along the Z direction.

[0038] exist Figure 4 In FIG. 1 , a hatching line toward the lower right is drawn on a portion of the piezoelectric element 240 where the common electrode 270 is provided on the XY plane. Figure 4 as well as Figure 5 As shown in FIG. 1 , the outer edge of the common electrode 270 in the Y direction, that is, the end Eg, is shown. Figure 4 as well as Figure 5 As shown, the common electrode 270 is provided so as to extend over the entire −Y direction of the end portion Eg, and is not provided in the +Y direction of the end portion Eg.

[0039] exist Figure 4 as well as Figure 5 In FIG. 1 , an active portion Ac and a passive portion NAc are shown. Figure 4 , a boundary Br between the active portion Ac and the passive portion NAc on the XY plane is shown by a bold line. The active portion Ac refers to a portion of the piezoelectric body 260 that is sandwiched by the common electrode 270 and the independent electrode 280 in the Z direction. The passive portion NAc refers to a portion of the piezoelectric body 260 that is not sandwiched by the common electrode 270 and the independent electrode 280 in the Z direction. Therefore, the passive portion NAc is a portion of the piezoelectric body 260 that is not provided with both the common electrode 270 and the independent electrode 280 in the Z direction of the piezoelectric body 260, or a portion that is provided with only one of the common electrode 270 and the independent electrode 280.

[0040] In the active portion Ac of the piezoelectric body 260, when a voltage is applied to the piezoelectric body 260 via the common electrode 270 and the independent electrode 280, piezoelectric deformation occurs. The piezoelectric element 240 changes the volume of the pressure chamber 221 by the displacement caused by the piezoelectric deformation. Specifically, the piezoelectric element 240 deforms the vibration plate 231 by the piezoelectric deformation of the piezoelectric body 260, thereby changing the volume of the pressure chamber 221. In addition, in the passive portion NAc of the piezoelectric body 260, piezoelectric deformation does not occur even when a voltage is applied to the piezoelectric body 260.

[0041] exist Figure 4 as well as Figure 5, the boundary between the end of the active portion Ac in the Y direction and the passive portion NAc, i.e., the boundary Br1, is shown. Generally speaking, at the boundary between the end of the active portion Ac in the extension direction and the passive portion NAc such as the boundary Br1, cracks etc. caused by the difference in displacement between the active portion Ac and the passive portion NAc are likely to occur. That is, since the active portion Ac of the piezoelectric body 260 sets the Y direction, which is the extension direction, as the long side direction, when a voltage is applied to the piezoelectric body 260, the active portion Ac is displaced more in the Y direction than in the X direction. In contrast, as described above, even when a voltage is applied to the piezoelectric body 260, the passive portion NAc does not generate piezoelectric deformation. Therefore, at the boundary such as the boundary Br1, cracks etc. are likely to occur due to the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc.

[0042] The piezoelectric body 260 has a first region R1 and a second region R2 when viewed along the Z direction. The first region R1 is a region including the boundary Br1 when viewed along the Z direction. Figure 4 In FIG. 1 , the hatching of the dot pattern is drawn on the first region R1. The second region R2 is a region different from the first region R1. Therefore, the second region R2 is a region that does not include the boundary Br1 when viewed along the Z direction. Figure 4 In the embodiment, the second region R2 is a region where the hatching of the dot pattern is not depicted in the portion where the piezoelectric body 260 is provided. Figure 5 As shown, the thickness of the piezoelectric body 260 in the first region R1 is thicker than that in the second region R2 of the piezoelectric body 260. That is, the first region R1 is a region including the boundary Br1 when viewed along the Z direction, and the piezoelectric body 260 is formed thicker than the second region R2.

[0043] Since the thickness of the piezoelectric body 260 in the first region R1 is thicker than the thickness of the piezoelectric body 260 in the second region R2, for example, compared with the case where the thickness of the piezoelectric body 260 in the first region R1 is equal to the thickness of the piezoelectric body 260 in the second region R2, the load generated in the first region R1 is easily dispersed in the Z direction, which is the thickness direction of the piezoelectric body 260. Therefore, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc in the above-mentioned boundary Br1 is reduced. In addition, since the thickness of the piezoelectric body 260 at the boundary Br1 is thicker, the electric field intensity generated in the piezoelectric body 260 at the boundary Br1 becomes smaller, and the piezoelectric body 260 is difficult to be damaged even when a higher voltage is applied to the piezoelectric body 260. Therefore, for example, the piezoelectric body 260 can be driven at a higher voltage, and the ejection amount of the liquid ejected by the liquid ejection head 200 can be increased.

[0044] In addition, it can be considered that even in the case where the thickness in the first region R1 is equal to the thickness of the piezoelectric body 260 in the second region R2, for example, by making the thickness of both thicker, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced compared to the case where the thickness of both is thin. However, in this case, the thickness of the piezoelectric body 260 is increased and the electric field strength is reduced in the second region R2 where cracks are less likely to occur than in the first region R1, so that it is possible that the displacement of the piezoelectric body 260 is less likely to occur. Therefore, the ejection characteristics of the liquid implemented by the liquid ejection head 200 may be reduced. In the present embodiment, as described above, since the thickness of the first region R1 is made thicker than the thickness of the second region R2, for example, the thickness of the first region R1 can be thickened while the thickness of the second region R2 is kept thin, and therefore, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 can be reduced while suppressing the reduction in such liquid ejection characteristics.

[0045] The range of the first region R1 is determined according to the range of the portion of the piezoelectric body 260 where the thickness is different. In the present embodiment, the width of the first region R1 in the X direction is equal to the width of the piezoelectric body 260 in the X direction. Therefore, the first region R1 is not adjacent to other regions in the X direction, so no boundary in the X direction between the first region R1 and other regions is generated, thereby improving the durability of the piezoelectric body 260 in the X direction. In addition, the width of the first region R1 in the Y direction is equal to the width of the groove Ga provided in the vibration plate 231, which will be described later, in the Y direction.

[0046] like Figure 4 as well as Figure 5 As shown, on the vibration plate 231 of the present embodiment, a groove Ga is provided along the X direction in a manner spanning a plurality of piezoelectric bodies 260. In the present embodiment, the thickness of the piezoelectric body 260 in the region overlapping with the groove Ga is formed to be thicker than the thickness in the region not overlapping with the groove Ga. That is, the region overlapping with the groove Ga in the piezoelectric body 260 corresponds to the first region R1, and the region not overlapping with the groove Ga corresponds to the second region R2. In addition, in the portion of the vibration plate 231 where the groove Ga is provided, the thickness of the vibration plate 231 is smaller than that of the portion of the vibration plate 231 where the groove Ga is not formed. Therefore, the thickness of the vibration plate 231 at the position overlapping with the first region R1 is smaller than the thickness of the vibration plate 231 at the position overlapping with the second region R2.

[0047] The groove Ga of this embodiment is formed by cutting a portion of the upper surface of the elastic layer 232 in the vibration plate 231. Figure 5As shown, the thickness of the elastic layer 232 at the position overlapping with the first region R1 is smaller than the thickness of the elastic layer 232 at the position overlapping with the second region R2. In addition, the thickness of the insulating layer 233 at the position overlapping with the first region R1 is equal to the thickness of the insulating layer 233 at the position overlapping with the second region R2. In addition, the thicknesses of the two may not be completely equal, and the thickness of the insulating layer 233 at the position overlapping with the second region R2 may be a thickness included in the range of ±10% of the thickness of the insulating layer 233 at the position overlapping with the first region R1. In general, since the elastic layer 232 is formed to be thicker than the insulating layer 233, the difference in the thickness of the vibration plate 231 in the first region R1 and the second region R2 can be increased by making the thickness of the elastic layer 232 different in the first region R1 and the second region R2.

[0048] like Figure 5 As shown, the piezoelectric body 260 has a first end face 261 and a second end face 262. The first end face 261 is an end face on the vibration plate 231 side of the piezoelectric body 260 in the Z direction, and in the present embodiment, is the lower surface of the piezoelectric body 260. The second end face 262 is an end face on the opposite side of the first end face 261 of the piezoelectric body 260 in the Z direction, and in the present embodiment, is the upper surface of the piezoelectric body 260. In the present embodiment, the second end face 262 in the first region R1 is located at the same position in the Z direction as the second end face 262 in the second region R2. In addition, the two may not be located at exactly the same position, as long as the position of the second end face 262 in the first region R1 in the Z direction and the position of the second end face 262 in the second region R2 in the Z direction are approximately the same position.

[0049] like Figure 5As shown, the vibration plate 231 has a third end face 236 and a fourth end face 237. The third end face 236 is an end face on the piezoelectric body 260 side of the vibration plate 231 in the Z direction, and in this embodiment, is the upper surface of the vibration plate 231. The fourth end face 237 is an end face on the opposite side of the third end face 236 in the Z direction of the vibration plate 231, and in this embodiment, is the lower surface of the vibration plate 231. That is, the insulating layer 233 of the vibration plate 231 has the third end face 236, and the elastic layer 232 has the fourth end face 237. In this embodiment, the fourth end face 237 at the position overlapping with the first region R1 is located at the same position in the Z direction as the fourth end face 237 at the position overlapping with the second region R2. Therefore, in this embodiment, the thickness of the vibration plate 231 is different at the position overlapping with the first region R1 and the position overlapping with the second region R2, and the thickness of the piezoelectric body 260 is different, but the total thickness of the vibration plate 231, the independent electrode 280, and the piezoelectric body 260 is equal. In addition, in other embodiments, the total thickness of the vibration plate 231, the independent electrode 280, and the piezoelectric body 260 may not be equal at the position overlapping with the first region R1 and the position overlapping with the second region.

[0050] For example, the piezoelectric portion 230 of the present embodiment can be manufactured by etching using a mask based on photolithography. An example of a method for manufacturing the piezoelectric portion 230 is described below. First, the elastic layer 232 of the vibration plate 231 is formed on the pressure chamber substrate 220 by thermal oxidation or CVD method. Next, a cut for forming the groove Ga is formed on the formed elastic layer 232 by etching or the like in a patterning manner, and the insulating layer 233 is formed on the elastic layer 232 by CVD method or the like. As described above, in the present embodiment, since one groove is formed as the groove Ga on the vibration plate 231, the groove Ga can be formed more easily than in the case where a plurality of grooves are formed. Furthermore, on the insulating layer 233, for example, the independent electrode 280 as the lower electrode is formed by sputtering using a material such as platinum as a target and etching to perform patterning. Then, the precursor of the piezoelectric body 260 produced by the sol-gel method or the like is applied to the insulating layer 233 of the vibration plate 231 and the independent electrode 280 by the spin coating method or the like, and the piezoelectric body 260 is formed by firing or the like. In the present embodiment, since the groove Ga is formed in the vibration plate 231, the thickness of the piezoelectric body 260 in the portion corresponding to the groove Ga can be easily increased by utilizing such a solution process, and the thickness in the first region R1 of the piezoelectric body 260 can be easily made thicker than the thickness in the second region R2 of the piezoelectric body 260. Thereafter, the common electrode 270 as the upper electrode is formed on the piezoelectric body 260, for example, by sputtering using a material such as platinum as a target, and etching to perform patterning. In addition, in each of the above-mentioned steps, etching or the like may be appropriately performed, for example, in order to smooth the surface of each component or adjust the thickness.

[0051] According to the liquid ejection head 200 of the first embodiment described above, the thickness of the piezoelectric body 260 in the first region R1 is thicker than the thickness of the piezoelectric body 260 in the second region R2. As a result, the load generated in the first region R1 is easily dispersed in the Z direction, which is the thickness direction of the piezoelectric body 260. Therefore, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced, and the generation of cracks and the like at the boundary Br1 is suppressed.

[0052] Furthermore, in the present embodiment, the thickness of the vibration plate 231 at the position overlapping the first region R1 is smaller than the thickness of the vibration plate 231 at the position overlapping the second region R2. Therefore, for example, the thickness of the piezoelectric body 260 can be easily made thicker in the first region R1 than in the second region R2 by forming the piezoelectric body 260 with a difference in thickness between the position overlapping the first region R1 and the position overlapping the second region R2 of the vibration plate 231.

[0053] Furthermore, in the present embodiment, the thickness of the elastic layer 232 at the position overlapping with the first region R1 is smaller than the thickness of the elastic layer 232 at the position overlapping with the second region R2. Therefore, by adjusting the thickness of the elastic layer 232, the thickness of the vibration plate 231 at the position overlapping with the first region R1 can be made smaller than the thickness of the vibration plate 231 at the position overlapping with the second region R2.

[0054] Furthermore, in the present embodiment, the thickness of the insulating layer 233 at the position overlapping the first region R1 is equal to the thickness of the insulating layer 233 at the position overlapping the second region R2. Therefore, without changing the thickness of the insulating layer 233 between the first region R1 and the second region R2, the thickness of the vibration plate 231 at the position overlapping the first region R1 can be made thicker than the thickness of the vibration plate 231 at the position overlapping the second region R2.

[0055] In the present embodiment, the second end surface 262 of the piezoelectric body 260 in the first region R1 is located at the same position in the stacking direction as the second end surface 262 in the second region R2. Therefore, the second end surface 262 of the piezoelectric body 260 is smooth.

[0056] In the present embodiment, the fourth end surface 237 of the vibration plate 231 overlapping the first region R1 is located at the same position as the fourth end surface 237 overlapping the second region R2 in the stacking direction. Therefore, the fourth end surface 237 of the vibration plate 231 is smooth.

[0057] In addition, in this embodiment, the common electrode 270, the piezoelectric body 260, the independent electrode 280, and the vibration plate 231 are sequentially stacked along the stacking direction. Therefore, even when the common electrode 270 is provided as the upper electrode and the independent electrode 280 is provided as the lower electrode, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced, and the generation of cracks at the boundary Br1 is suppressed. Therefore, the degree of freedom of the structure of the piezoelectric element 240 is increased.

[0058] In this embodiment, the width of the first region R1 in the arrangement direction is equal to the width of the piezoelectric body 260 in the arrangement direction. Therefore, the first region R1 is not adjacent to other regions in the arrangement direction, thereby improving the durability of the piezoelectric body 260 in the arrangement direction.

[0059] B. Second Implementation Method:

[0060] Figure 6 FIG. 2 is a diagram for explaining a schematic structure of the piezoelectric portion 230 b in the second embodiment. Figure 6 In, with Figure 4The case of the first embodiment shown in the figure also shows a portion where the pressure chamber 221 is formed on the XY plane and a portion where various components constituting the piezoelectric element 240b described later are provided. The first region R1 of this embodiment is different from the first embodiment in that the width of the first region R1 in the X direction is smaller than the width of the piezoelectric body 260b in the X direction. In addition, the portions not particularly described in the structure of the liquid ejection device 100 and the liquid ejection head 200 of the second embodiment are the same as those of the first embodiment.

[0061] Figure 7 for Figure 6 VII-VII cross-sectional view of the piezoelectric portion 230b in FIG. As described above, since the width of the first region R1 in the X direction of the present embodiment is smaller than the width of the piezoelectric body 260b in the X direction, there are regions different from the first region R1 in the +X direction and -X direction of the first region R1. Specifically, in the present embodiment, the second region R2 is located in the +X direction and -X direction of the first region R1. In the present embodiment, since the load generated in the first region R1 is easily dispersed in the Z direction, which is the thickness direction of the piezoelectric body 260b, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced. In addition, since the width of the first region R1 in the X direction is smaller than the width of the piezoelectric body 260b in the X direction, the dimension of the boundary in the X direction between the first region R1 and other regions in the Y direction is smaller than the width of the piezoelectric body 260b in the X direction, and therefore, at the boundary in the Y direction between the first region R1 and other regions, the generation of cracks and the like is suppressed. Therefore, the durability of the piezoelectric body 260 b in the Y direction is improved.

[0062] In the vibration plate 231b of the present embodiment, unlike the first embodiment, a plurality of grooves Gb are independently formed in a manner corresponding to the plurality of piezoelectric bodies 260b. The dimension of the groove Gb in the X direction of the present embodiment is smaller than the dimension of the piezoelectric body 260b in the X direction. In the present embodiment, as in the first embodiment, the thickness of the region overlapping with the groove Gb in the piezoelectric body 260b is formed to be thicker than the thickness of the region not overlapping with the groove Gb. That is, in the present embodiment, the region overlapping with the groove Gb in the piezoelectric body 260b is equivalent to the first region R1, and the region not overlapping with the groove Gb is equivalent to the second region R2. In addition, in the present embodiment, the dimensions of the first region R1 in the X direction and the Y direction are equal to the dimensions of the groove Gb in the X direction and the Y direction. In addition, the groove Gb of the present embodiment is formed by cutting a portion of the upper surface of the elastic layer 232b in the same manner as in the first embodiment.

[0063] Since the plurality of grooves Gb are independently provided in a manner corresponding to the plurality of piezoelectric bodies 260b, the durability of the vibration plate 231b is improved compared to the case where one groove is formed across the plurality of piezoelectric bodies 260b. In addition, when the independent electrode 280 as the lower electrode is patterned by etching, the plurality of grooves Gb are independently formed in a manner corresponding to the plurality of piezoelectric bodies 260b, and the independent electrodes 280 corresponding to the plurality of piezoelectric bodies 260b are easily patterned separately. Therefore, the efficiency of forming the independent electrode 280 can be improved.

[0064] Even in the liquid ejection head 200 according to the second embodiment described above, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced, and the generation of cracks and the like at the boundary Br1 is suppressed. In particular, in the present embodiment, the width of the first region R1 in the arrangement direction is smaller than the width of the piezoelectric body 260b in the arrangement direction. Thus, the dimension of the boundary in the extension direction between the first region R1 and other regions is smaller than the width of the piezoelectric body 260b in the arrangement direction, thereby improving the durability of the piezoelectric body 260b in the extension direction.

[0065] C. Third Implementation Method:

[0066] Figure 8 2 is a diagram showing a cross section of the pressure chamber 221 and the piezoelectric portion 230c along the XZ plane in the third embodiment. Figure 8 In, with Figure 5 The case of the first embodiment shown in the figure also shows the vibration plate 231 and the piezoelectric element 240c. In this embodiment, unlike the first embodiment, along the Z direction as the stacking direction, from the +Z direction, the independent electrode 280c, the piezoelectric body 260, the common electrode 270c and the vibration plate 231 are stacked in sequence. That is, the common electrode 270c is a lower electrode stacked on the lower part of the piezoelectric body 260, and the independent electrode 280c is an upper electrode stacked on the upper part of the piezoelectric body 260. In addition, the parts not particularly described in the structure of the liquid ejection device 100 and the liquid ejection head 200 of the third embodiment are the same as those of the first embodiment.

[0067] Even in the liquid ejection head 200 according to the third embodiment described above, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced, and the generation of cracks and the like at the boundary Br1 is suppressed. In particular, in this embodiment, the independent electrode 280c, the piezoelectric body 260, the common electrode 270c, and the vibration plate 231 are stacked in sequence along the Z direction. Therefore, even in the case where the common electrode 270c is provided as the lower electrode and the independent electrode 280c is provided as the upper electrode, the stress caused by the difference in displacement between the active portion Ac and the passive portion NAc at the boundary Br1 is reduced, and the generation of cracks and the like at the boundary Br1 is suppressed. Therefore, the degree of freedom of the structure of the piezoelectric element 240c is increased.

[0068] D. Other implementation methods:

[0069] (D-1) In the above embodiment, the thickness of the vibration plate 231 at the position overlapping with the first region R1 is smaller than the thickness of the vibration plate 231 at the position overlapping with the second region R2. In contrast, the thickness of the vibration plate 231 at the position overlapping with the first region R1 may be the same as the thickness of the vibration plate 231 at the position overlapping with the second region R2, or may be thicker than the thickness of the vibration plate 231 at the position overlapping with the second region R2. For example, in the first region R1 and the second region R2, the thickness of the vibration plate 231 may be the same, and the thickness of the piezoelectric body 260 may be different. Therefore, as long as the thickness of the piezoelectric body 260 in the first region R1 is thicker than the thickness of the piezoelectric body 260 in the second region R2, the region where the thickness of the vibration plate 231 is different and the region where the thickness of the piezoelectric body 260 is different may not correspond to each other. For example, as in the above-mentioned first to third embodiments, in the case where a groove is provided in the vibration plate 231, the range of the first region R1 may be a region smaller than the region of the piezoelectric body 260 overlapping with the groove.

[0070] (D-2) In the above embodiment, the thickness of the elastic layer 232 at the position overlapping with the first region R1 is smaller than the thickness of the elastic layer 232 at the position overlapping with the second region R2. In contrast, the thickness of the elastic layer 232 at the position overlapping with the first region R1 may be the same as the thickness of the elastic layer 232 at the position overlapping with the second region R2, or may be thicker than the thickness of the elastic layer 232 at the position overlapping with the second region R2.

[0071] (D-3) In the above embodiment, the thickness of the insulating layer 233 at the position overlapping with the first region R1 is equal to the thickness of the insulating layer 233 at the position overlapping with the second region R2. In contrast, the thickness of the insulating layer 233 at the position overlapping with the first region R1 may be thicker than the thickness of the insulating layer 233 at the position overlapping with the second region R2, or may be thinner than the thickness of the insulating layer 233 at the position overlapping with the second region R2.

[0072] (D-4) In the above embodiment, the second end face 262 of the piezoelectric body 260 in the first region R1 is located at the same position in the stacking direction as the second end face 262 in the second region R2. In contrast, the second end face 262 in the first region R1 may not be located at the same position in the stacking direction as the second end face 262 in the second region R2.

[0073] (D-5) In the above embodiment, the fourth end surface 237 of the vibration plate 231 at the position overlapping with the first region R1 is located at the same position in the stacking direction as the fourth end surface 237 at the position overlapping with the second region R2. In contrast, the fourth end surface 237 at the position overlapping with the first region R1 may not be located at the same position in the stacking direction as the fourth end surface 237 at the position overlapping with the second region R2.

[0074] E. Other ways:

[0075] The present disclosure is not limited to the above-mentioned embodiments, and can be implemented in various ways without departing from its main purpose. For example, the present disclosure can be implemented in the following ways. In order to solve part or all of the problems of the present disclosure, or to achieve part or all of the effects of the present disclosure, the technical features in the above-mentioned embodiments corresponding to the technical features in the various modes described below can be appropriately replaced or combined. In addition, if the technical feature is not described as a necessary technical feature in this specification, it can be appropriately deleted.

[0076] (1) According to a first aspect of the present disclosure, there is provided a liquid ejection head, comprising: a plurality of piezoelectric bodies; independent electrodes independently provided with respect to the plurality of piezoelectric bodies; a common electrode commonly provided with respect to the plurality of piezoelectric bodies; and a vibration plate that vibrates by electrically driving the piezoelectric bodies via the independent electrodes and the common electrode. In the liquid ejection head, the piezoelectric bodies, the independent electrodes, the common electrode, and the vibration plate are stacked in a stacking direction, and when a portion of the piezoelectric body sandwiched by the independent electrodes and the common electrode in the stacking direction is set as an active portion, a portion of the piezoelectric body not sandwiched by the independent electrodes and the common electrode in the stacking direction is set as a passive portion, a region of the piezoelectric body including an end of the active portion in an extending direction of the independent electrodes and a boundary of the passive portion when viewed along the stacking direction is set as a first region, and a region of the piezoelectric body different from the first region is set as a second region, the thickness of the piezoelectric body in the first region is thicker than the thickness of the piezoelectric body in the second region.

[0077] According to this method, the load generated in the first region is easily dispersed in the thickness direction of the piezoelectric body. Therefore, the stress caused by the difference in displacement between the active part and the passive part at the end of the active part and the boundary of the passive part in the extension direction is reduced, and the generation of cracks is suppressed.

[0078] (2) In the liquid ejection head of the above-mentioned method, the following method may be adopted, that is, the thickness of the vibration plate at the position overlapping with the first region is smaller than the thickness of the vibration plate at the position overlapping with the second region. According to such a method, for example, the thickness of the piezoelectric body can be formed by making the thickness of the piezoelectric body different by the difference in thickness between the position overlapping with the first region and the position overlapping with the second region of the vibration plate, thereby easily making the thickness of the piezoelectric body in the first region thicker than the thickness of the piezoelectric body in the second region.

[0079] (3) In the liquid ejection head of the above-mentioned method, the vibration plate may include an elastic layer and an insulating layer, the insulating layer being located closer to the piezoelectric body than the elastic layer in the stacking direction, and the thickness of the elastic layer at a position overlapping the first region is smaller than the thickness of the elastic layer at a position overlapping the second region. According to such a method, the thickness of the vibration plate at a position overlapping the first region can be made smaller than the thickness of the vibration plate at a position overlapping the second region by adjusting the thickness of the elastic layer.

[0080] (4) In the liquid ejection head of the above-mentioned method, the following method may be adopted, that is, the thickness of the insulating layer at the position overlapping with the first region is equal to the thickness of the insulating layer at the position overlapping with the second region. According to this method, the thickness of the vibrating plate at the position overlapping with the first region can be made thicker than the thickness of the vibrating plate at the position overlapping with the second region without changing the thickness of the insulating layer in the first region and the second region.

[0081] (5) In the liquid ejection head of the above-mentioned method, the piezoelectric body may have an end face on the vibration plate side in the stacking direction, that is, a first end face and a second end face on the opposite side, and the second end face in the first region is located at the same position as the second end face in the second region in the stacking direction. According to this method, the second end face of the piezoelectric body becomes smooth.

[0082] (6) In the liquid ejection head of the above-mentioned method, the following method may be adopted, that is, the vibration plate has an end face on the piezoelectric body side in the stacking direction, that is, a third end face and a fourth end face on the opposite side, and the fourth end face at a position overlapping with the first area is located at the same position in the stacking direction as the fourth end face at a position overlapping with the second area. According to this method, the fourth end face of the vibration plate becomes smooth.

[0083] (7) In the liquid ejection head of the above-mentioned method, the following method may also be adopted, that is, the common electrode, the piezoelectric body, the independent electrode and the vibration plate are stacked in sequence along the stacking direction. According to such a method, even when the common electrode is provided as the upper electrode and the independent electrode is provided as the lower electrode, the generation of cracks and the like is suppressed. Therefore, the degree of freedom of the structure of the common electrode or the independent electrode is increased.

[0084] (8) In the liquid ejection head of the above-mentioned method, the following method may also be adopted, that is, the independent electrode, the piezoelectric body, the common electrode and the vibration plate are stacked in sequence along the stacking direction. According to such a method, even when the common electrode is provided as the lower electrode and the independent electrode is provided as the upper electrode, the generation of cracks and the like is suppressed. Therefore, the degree of freedom of the structure of the common electrode or the independent electrode is increased.

[0085] (9) In the liquid ejection head of the above aspect, the plurality of piezoelectric bodies may be arranged along an arrangement direction orthogonal to the extending direction.

[0086] (10) In the liquid ejection head of the above aspect, a aspect may be adopted in which the width of the first region in the arrangement direction is equal to the width of the piezoelectric body in the arrangement direction.

[0087] According to such an aspect, since the first region is not adjacent to other regions in the arrangement direction, the durability of the piezoelectric body in the arrangement direction is improved.

[0088] (11) In the liquid ejection head of the above aspect, a aspect may be adopted in which the width of the first region in the arrangement direction is smaller than the width of the piezoelectric body in the arrangement direction.

[0089] According to such an aspect, since the dimension of the boundary in the extending direction between the first region and the other regions in the arrangement direction is smaller than the width of the piezoelectric body in the arrangement direction, the durability of the piezoelectric body in the extending direction is improved.

[0090] (12) According to a second aspect of the present disclosure, there is provided a liquid ejection device comprising: the liquid ejection head according to the first aspect; and a control unit that controls an ejection operation from the liquid ejection head.

[0091] According to this method, the load generated in the first region is easily dispersed in the thickness direction of the piezoelectric body. Therefore, the stress caused by the difference in displacement between the active part and the passive part at the boundary in the extension direction of the end of the active part and the passive part is reduced, and the generation of cracks is suppressed.

[0092] The present disclosure is not limited to the above-mentioned liquid ejection head and liquid ejection device, and can be implemented in various forms such as a liquid ejection system or a multifunction machine including a liquid ejection device.

[0093] Explanation of symbols

[0094] 40… carriage; 41… flexible cable; 46… driving motor; 47… driving belt; 51… conveying motor; 80… ink cartridge; 90… driving circuit; 100… liquid ejection device; 110… control unit; 200… liquid ejection head; 210… nozzle plate; 211… nozzle; 220… pressure chamber substrate; 221… pressure chamber; 223… ink supply channel; 225… connecting unit; 230, 230b, 230c… piezoelectric unit; 231, 231b… vibration plate ; 232, 232b…elastic layer; 233…insulating layer; 236…third end face; 237…fourth end face; 240, 240b, 240c…piezoelectric element; 250…sealing portion; 251…piezoelectric element holding portion; 252…manifold portion; 260, 260b…piezoelectric body; 261…first end face; 262…second end face; 270, 270c…common electrode; 280, 280c…independent electrode; 293…manifold; 295…lead electrode.

Claims

1. A liquid ejection head, characterized in that: have: A plurality of piezoelectric bodies; Independent electrodes are independently arranged relative to the plurality of piezoelectric bodies; a common electrode disposed in common with respect to the plurality of piezoelectric bodies; a vibration plate that vibrates by electrically driving the piezoelectric body via the independent electrode and the common electrode, The piezoelectric body, the independent electrode, the common electrode, and the vibration plate are stacked in a stacking direction. When a portion of the piezoelectric body that is sandwiched by the independent electrode and the common electrode in the stacking direction is set as an active portion, a portion of the piezoelectric body that is not sandwiched by the independent electrode and the common electrode in the stacking direction is set as a passive portion, a region of the piezoelectric body including an end of the active portion in the extending direction of the independent electrode and a boundary of the passive portion when observed along the stacking direction is set as a first region, and a region of the piezoelectric body that is different from the first region is set as a second region, The thickness of the piezoelectric body in the first region is thicker than the thickness of the piezoelectric body in the second region, A thickness of the vibration plate at a position overlapping the first region is smaller than a thickness of the vibration plate at a position overlapping the second region.

2. The liquid ejection head according to claim 1, wherein: The vibration plate includes an elastic layer and an insulating layer, wherein the insulating layer is located closer to the piezoelectric body than the elastic layer in the stacking direction. A thickness of the elastic layer at a position overlapping the first region is smaller than a thickness of the elastic layer at a position overlapping the second region.

3. The liquid ejection head according to claim 2, wherein: A thickness of the insulating layer at a position overlapping the first region is equal to a thickness of the insulating layer at a position overlapping the second region.

4. The liquid ejection head according to any one of claims 1 to 3, wherein: The piezoelectric body has a first end face which is an end face on the vibration plate side in the stacking direction and a second end face on the opposite side. The second end surface in the first region is located at the same position as the second end surface in the second region in the stacking direction.

5. The liquid ejection head according to claim 1, wherein: The vibration plate has a third end surface which is an end surface on the piezoelectric body side in the stacking direction and a fourth end surface on the opposite side. The fourth end surface at a position overlapping with the first region is located at the same position in the stacking direction as the fourth end surface at a position overlapping with the second region.

6. The liquid ejection head according to claim 1, wherein: The common electrode, the piezoelectric body, the independent electrode, and the vibration plate are sequentially stacked along the stacking direction.

7. The liquid ejection head according to claim 1, wherein: The individual electrodes, the piezoelectric body, the common electrode, and the vibration plate are sequentially stacked along the stacking direction.

8. The liquid ejection head according to claim 1, wherein: The plurality of piezoelectric bodies are arranged along an arrangement direction orthogonal to the extending direction.

9. The liquid ejection head according to claim 8, wherein: The width of the first region in the arrangement direction is equal to the width of the piezoelectric body in the arrangement direction.

10. The liquid ejection head according to claim 8, wherein The width of the first region in the arrangement direction is smaller than the width of the piezoelectric body in the arrangement direction.

11. A liquid ejection device, characterized in that: have: The liquid ejection head according to any one of claims 1 to 10; A control unit controls the discharge operation from the liquid discharge head.

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