Liquid nozzle

Abstract

The present invention provides a liquid ejecting head and a liquid ejecting device that can be miniaturized. A liquid ejecting head according to one embodiment includes an FPC and a plurality of piezoelectric elements. The FPC includes: an electrode layer having a first region and a second region; and a covering layer stacked on the second region of the electrode layer. The plurality of piezoelectric elements are arranged opposite to the first region of the electrode layer of the FPC, and include: a bonding surface connected to the first region of the electrode layer; and a retreat surface having a step retreated from the FPC in the first direction relative to the bonding surface.

Description

Technical Field

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

[0002] Piezoelectric actuators using piezoelectric materials such as PZT are used as the driving source for liquid ejection devices such as inkjet printer heads. In inkjet printer heads, actuators are arranged at very fine intervals, and the wiring connected to drive the actuators is also thinner. For example, to accommodate wiring with a fine pitch of around 100 μm, a flexible printed circuit board (hereinafter referred to as FPC) is sometimes directly soldered to the electrodes on the piezoelectric material. In such piezoelectric actuators, the electrodes on the side where the FPC is mounted are treated as separate electrodes, soldered and mounted on this side, and a chamfering process is performed to tilt a portion of the side. In FPCs, a base made of polyimide or the like and an insulating covering made of the same thickness and material as the base are bonded together using an adhesive. If the solder plating becomes thicker, it may warp due to stress, etc. If the solder plating is thicker with a fine pitch, it may sometimes connect to other electrodes and wiring, so the thickness is generally less than around 10 μm. If the insulating covering is thick, the mounting area becomes smaller, or the FPC needs to be lengthened to ensure a secure mounting area. Summary of the Invention

[0003] [Technical problem to be solved by the invention]

[0004] The technical problem to be solved by the present invention is to provide a liquid ejecting head that can be miniaturized.

[0005] Means for solving technical problems

[0006] A liquid ejecting head according to one embodiment includes an FPC and a plurality of piezoelectric elements. The FPC includes an electrode layer having a first region and a second region; and a cover layer laminated on the second region of the electrode layer. The plurality of piezoelectric elements are arranged opposite the first region of the electrode layer of the FPC and include a bonding surface connected to the first region of the electrode layer; and a setback surface having a step set back from the FPC in the first direction relative to the bonding surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a cross-sectional view showing a partial structure of the inkjet head according to the first embodiment.

[0008] Figure 2 It is a cross-sectional view showing a partial structure of the inkjet head.

[0009] Figure 3 It is a perspective view showing the structure of the piezoelectric component of the inkjet head.

[0010] Figure 4It is a cross-sectional view showing the structure of the FPC of the inkjet head.

[0011] Figure 5 It is an explanatory diagram showing a method for manufacturing the inkjet head.

[0012] Figure 6 It is an explanatory diagram showing a schematic configuration of the inkjet recording apparatus according to the first embodiment.

[0013] Figure 7 It is a cross-sectional view showing a partial structure of an inkjet head according to another embodiment.

[0014] Figure 8 It is a cross-sectional view showing a partial structure of an inkjet head according to another embodiment.

[0015] Figure 9 It is a cross-sectional view showing a partial structure of an inkjet head according to another embodiment. DETAILED DESCRIPTION

[0016] Below, refer to Figures 1 to 6 Next, an inkjet head 1 as a liquid ejecting head and an inkjet recording apparatus 100 as a liquid ejecting device according to a first embodiment will be described. Figure 1 and Figure 2 is a cross-sectional view showing a schematic structure of a part of the inkjet head 1. Figure 3 It is a perspective view showing the structure of a piezoelectric component. Figure 4 is an explanatory diagram showing the structure of an FPC, Figure 5 It is an explanatory diagram showing a method of manufacturing the inkjet head 1 . Figure 6 1 is an explanatory diagram showing a schematic configuration of an inkjet recording apparatus 100. Arrows X, Y, and Z in the diagram respectively indicate three mutually orthogonal directions. In each diagram, the configuration is appropriately enlarged, reduced, or omitted for ease of explanation.

[0017] like Figures 1 to 4 As shown, the inkjet head 1 includes a substrate 10 , a piezoelectric member 20 , a vibration plate 30 , a manifold 40 , a nozzle plate 50 having a plurality of nozzles 51 , a frame 60 , and an FPC 70 .

[0018] The piezoelectric component 20 includes a single or multiple piezoelectric elements 21. For example, one side of the piezoelectric component 20 is divided into multiple parts by multiple grooves 22, and the multiple piezoelectric elements 21 and the multiple grooves 22 are alternately arranged in parallel along the third direction indicated by X in the figure.

[0019] The piezoelectric element 21 is an actuator comprising: a plurality of piezoelectric layers 23 stacked in a first direction (Z direction) in the figure; a dummy layer 24; internal electrodes 221 and 222 formed on the principal surfaces of each piezoelectric layer 23; and external electrodes 231 and 232. The piezoelectric element 21 is disposed, for example, at an end portion of the substrate 10 on one side in the first direction and bonded to the substrate 10.

[0020] The piezoelectric layer 23 is formed into a thin plate of a piezoelectric material such as PZT (lead zirconate titanate) or lead-free KNN (sodium potassium niobate). The plurality of piezoelectric layers 23 are stacked with their thickness along the first direction and bonded to each other by an adhesive layer.

[0021] The internal electrodes 221 and 222 are conductive films formed in a predetermined shape from a sinterable conductive material such as silver palladium. The internal electrodes 221 and 222 are formed in a predetermined area on the main surface of each piezoelectric layer 23. The internal electrodes 221 and 222 have different poles. For example, one internal electrode 221 is formed in an area that reaches one end of the piezoelectric layer 23 in the second direction shown in the Y direction in the figure but does not reach the other end. The second direction is a direction orthogonal to the first direction, which is the stacking direction. The other internal electrode 222 is formed in an area that does not reach one end of the piezoelectric layer 23 in the second direction shown in the Y direction in the figure but reaches the other end. The internal electrodes 221 and 222 are respectively connected to the external electrodes 231 and 232 formed on the side surfaces of the piezoelectric element 21.

[0022] The external electrodes 231 and 232 are formed on the side surface of the piezoelectric element 21, and are composed of the ends of the internal electrodes 221 and 222. For example, the external electrodes 231 and 232 are respectively formed on one end surface and the other end surface in the second direction perpendicular to the stacking direction. The external electrodes 231 and 232 are formed into films of Ni, Cr, Au, etc. by known methods such as electroplating and sputtering. The outermost surface of the welded joint described below is preferably Au. The external electrode 231 and the external electrode 232 are, for example, different poles, and the external electrode 231 and the external electrode 232 are respectively arranged on different side surfaces. Alternatively, the external electrodes 231 and 232 can also be coiled in different areas of the same side surface.

[0023] In this embodiment, as an example, the external electrode 231 is set as an individual electrode, and the external electrode 232 is set as a common electrode. Figure 3 and Figure 5 As shown, the electrode layers of the external electrodes 231 serving as individual electrodes of the plurality of piezoelectric elements 21 are divided by grooves and arranged independently of each other. In the external electrode 232 serving as a common electrode, the electrode layers are connected to each other in a region closer to the base than the grooves, for example, to ground.

[0024] The external electrodes 231 serving as individual electrodes are connected to the FPC 70 and are connected to mounted components such as a driver IC via various wirings.

[0025] Dummy layer 24 is made of the same material as piezoelectric layer 23. Dummy layer 24 has an electrode only on one side and, because no electric field is applied, does not deform. In other words, dummy layer 24 does not function as a piezoelectric element, but instead serves as a base for mounting and a polishing table for precision grinding during and after assembly.

[0026] A step 25 is formed at the end of the piezoelectric element 21 on the individual electrode side. A relief surface 26 is formed on the substrate 10 side of the end surface of the piezoelectric element 21, which is recessed away from the FPC 70. A bonding surface 27 is formed on the pressure chamber 31 side opposite the substrate 10 side, protruding toward the FPC 70. Relief surface 26 and bonding surface 27 are located on one side and the other side of the step 25 in the first direction, respectively, and extend in a planar direction along the first direction, which is the stacking direction, and the third direction, which is the arrangement direction of the pressure chambers. The depth D of the step 25 is shallower than the length (L) of the unstacked portion of the common internal electrodes 221 and 222 in the piezoelectric element 21 in the first direction, and deeper than the difference in position between the electrode layer 72 and the insulating cover layer 75, that is, the difference in thickness (T) between the surface of the insulating cover layer 75 and the mounting portion. For example, the step 25 is provided in the dummy layer 24. In other words, the portion of the piezoelectric element 21 that does not function as a piezoelectric body and does not deform is partially cut away. It should be noted that the step portion 25 may also be located in the piezoelectric layer 23. In this case, it is arranged at a position avoiding the internal electrodes 221, 222 and the external electrodes 231, 232. Due to the step portion 25, a portion of the insulating cover layer 75 of the FPC 70 is arranged in the space formed between the base layer 71 of the FPC 70 and the piezoelectric element 21.

[0027] As an example, each piezoelectric element 21 has the following configuration: the number of stacked piezoelectric layers 23 is 50 or less; the thickness of each layer is 10 μm to 40 μm; and the product of the thickness and the total number of stacked layers is less than 1000 μm.

[0028] The piezoelectric element 21 vibrates longitudinally along the stacking direction of the piezoelectric layer 23 by applying a voltage to the internal electrodes 221 and 222 via the external electrodes 231 and 232. For example, the longitudinal vibration referred to here refers to "vibration in the thickness direction defined by the piezoelectric constant d33." It should be noted that, in this embodiment, as an example, Figure 2 As shown, half of the piezoelectric elements 21 arranged in parallel are arranged corresponding to the pressure chamber 31 via the vibration plate 30 , and the remaining half of the piezoelectric elements 21 are arranged at positions opposite to the partition wall portion 42 via the vibration plate 30 .

[0029] The vibration plate 30 is arranged, for example, with its thickness direction aligned with a first direction serving as the stacking direction, and extends in a plane direction perpendicular to the first direction. The vibration plate 30 is arranged on one side of the piezoelectric element 21 in the stacking direction, i.e., on the nozzle plate 50 side. For example, the vibration plate 30 includes multiple vibration sites 301 that are opposed to each pressure chamber 31 and are independently displaceable, with the multiple vibration sites 301 being integrally connected. Alternatively, multiple vibration plates 30 that are independently displaceable may be arranged.

[0030] The vibration plate 30 is joined to an end surface on one side of the piezoelectric element 21. As an example, in the present embodiment, in the main surface on one side of the first direction of the vibration plate 30, the areas at both ends in the second direction are joined to the manifold 40. In the central portion in the second direction of the inkjet head 1, a pressure chamber 31 capable of accommodating ink and a guide flow path 34 are formed between the vibration plate 30 and the manifold 40. An area on one end side of the main surface on the other side of the first direction of the vibration plate 30 is joined to the piezoelectric element 21, and a prescribed area on the other end side in the second direction is joined to the frame 60. A common chamber 32 capable of accommodating ink is formed between the main surface on the other side of the first direction of the vibration plate 30 and the frame 60. That is, one side of the vibration plate 30 faces the piezoelectric element 21, and the other side faces the pressure chamber 31, the partition wall portion 42, and the guide flow path 34.

[0031] Each pressure chamber 31 communicates with a nozzle 51 formed on a nozzle plate 50 arranged on one side in the first direction. The plurality of pressure chambers 31 and guide flow paths 34 arranged in the third direction are separated from each other by partition walls 42 provided in the manifold 40 .

[0032] The vibration plate 30 has an opening 33 extending through the plate in the thickness direction and connecting the pressure chambers 31 and the common chamber 32. The pressure chambers 31 are formed on one side of the vibration plate 30 in the first direction, and the common chamber 32 is formed on the other side of the vibration plate 30 in the first direction. The common chamber 32 extends in the third direction and connects to the plurality of pressure chambers 31 arranged in the third direction. The vibration plate 30 deforms in response to the deformation of the piezoelectric element 21, causing the volume of the pressure chambers 31 to change.

[0033] The manifold 40 is joined to one side of the vibration plate 30. The manifold 40 is arranged between the nozzle plate 50 and the vibration plate 30 and defines a predetermined ink flow path 35. The ink flow path 35 includes a plurality of pressure chambers 31 separated by partition walls 42 and a guide flow path 34 extending in the second direction from the plurality of pressure chambers 31 toward the opening 33. The manifold 40 includes a frame-shaped portion 41 joined to the outer edge of the vibration plate 30; a plurality of partition walls 42 separating the plurality of ink flow paths 35; and a guide wall 43 forming the guide flow path 34. One side of the plurality of pressure chambers 31 is blocked by the nozzle plate 50 and communicates with the nozzles 51. The other side is blocked by the vibration plate 30 and communicates with the common chamber 32 via the guide flow path 34 and the opening 33. The pressure chambers 31 retain liquid supplied from the common chamber 32 through the guide flow path 34 and are deformed by the vibration of the vibration plate 30, causing the liquid to be ejected from the nozzles 51.

[0034] The nozzle plate 50 is a square plate with a thickness of approximately 10 to 100 μm, made of, for example, a metal such as SUS or Ni, or a resin material such as polyimide. The nozzle plate 50 is positioned on one side of the manifold 40 so as to cover the opening on one side of the pressure chambers 31. The nozzle plate 50 is formed with a plurality of nozzles 51 extending through the thickness of the nozzle plate 50. The nozzles 51 are arranged in a third direction to form a nozzle row. Each nozzle 51 is positioned corresponding to one of the plurality of pressure chambers 31.

[0035] The frame 60 is disposed on the other side of the vibration plate 30 in the first direction. The frame 60 forms a common chamber 32 between the frame 60 and the vibration plate 30. The common chamber 32 is formed inside the frame 60 and communicates with the pressure chamber 31 through an opening 33 provided in the vibration plate 30 and a guide flow path 34.

[0036] The FPC 70 is connected to the individual electrodes and includes a base layer 71 , an electrode layer 72 , a solder plating layer 73 , an adhesive layer 74 , and an insulating cover layer 75 .

[0037] The base layer 71 is mainly made of polyimide and is in the form of a sheet of a predetermined thickness. The electrode layer 72 is made of a conductive material such as metal and is formed on the surface of the base layer 71 in a predetermined pattern. A solder-plated layer 73 is formed in a first area of the surface of the electrode layer 72 that becomes the bonding area with the piezoelectric element 21. The solder-plated layer 73 is plated with solder to have a thickness of approximately 3 to 10 μm. In a second area other than the bonding area of the surface of the electrode layer 72, an insulating covering layer 75 is formed via an adhesive layer 74. Here, for example, one end side in the first direction of the FPC 70 is set as the first area, and the other end side is set as the second area.

[0038] The FPC 70 is aligned with the first region having the solder plating layer 73 opposite the bonding surface 27 of the piezoelectric element 21, and then heated to melt the solder of the solder plating layer 73, thereby electrically and mechanically connecting the FPC 70 to the external electrode 231. Heating can be performed using a conventional heating tool, or by irradiating the FPC 70 with an infrared laser or the like that penetrates the base layer 71.

[0039] For example, due to the difference between the combined thickness of the insulating cover layer 75 and the adhesive layer 74 and the thickness of the solder plating layer 73, the thickness of the second region becomes greater than the thickness of the first region, forming a step on the surface of the FPC 70. For example, the dimension T of the step in the thickness direction is 50 to 100 μm.

[0040] In FPC 70, at least a portion of the second region where insulating cover layer 75 and adhesive layer 74 are formed, forming a thick portion, is disposed opposite to recessed surface 26. Specifically, the region where insulating cover layer 75 and adhesive layer 74 are laminated is disposed in the space formed by the step of recessed surface 26. Solder plated layer 73 is disposed opposite to bonding surface 27, and insulating cover layer 75 is disposed opposite to recessed surface 26.

[0041] In the inkjet head 1 constructed as described above, an ink flow path 35 is formed by the nozzle plate 50, the frame 60, the manifold 40, and the vibration plate 30. The ink flow path 35 includes a plurality of pressure chambers 31 connected to the nozzles 51, a plurality of guide flow paths 34, and a common chamber 32 connected to the plurality of pressure chambers 31. For example, the common chamber 32 is connected to an ink cartridge, and ink is supplied to each pressure chamber 31 through the common chamber 32. In the inkjet head 1, when a driving voltage is applied to the electrodes 221 and 222 via the driver IC, the piezoelectric element 21 vibrates in the stacking direction, that is, in the thickness direction of each piezoelectric layer 23. In other words, it vibrates longitudinally. The longitudinal vibration of the piezoelectric element 21 causes the vibration plate 30 to vibrate, and the vibration in the first direction causes the pressure chamber 31 to deform. As a result, as the internal volume of the pressure chamber 31 changes, ink is guided from the common chamber 32 and ejected from the nozzle 51.

[0042] In the process of manufacturing the inkjet head 1 according to this embodiment, the internal electrodes 221 and 222 are printed on a sheet of piezoelectric material to form a piezoelectric layer 23 having the internal electrodes 221 and 222. Then, a plurality of piezoelectric layers 23 having the internal electrodes 221 and 222 are stacked in a first direction and fired to form a stacked piezoelectric body 201. Figure 5As shown, external electrodes 231 and 232 are formed by printing on one end face and the other end face in the second direction of the stacked piezoelectric body 201. Then, a step 25 is formed on one end of the external electrode 231, which is arranged as an individual electrode, by cutting. Forming the step 25 removes the electrode layer from the substrate 10 side of the external electrode 231. Furthermore, by forming multiple grooves 22 with a depth reaching the area where the electrode layer is removed by the step 25, one side of the stacked piezoelectric body 201 is divided into multiple pieces, forming multiple piezoelectric elements 21. This results in a piezoelectric component 20 with one end divided into multiple pieces and the other end connected. Here, by setting the grooves 22 to a depth reaching the area where the electrode layer is removed, the electrode layer on the side where the step 25 is arranged becomes separate and independent individual electrodes. Meanwhile, the electrode layer on the side where the step is not formed forms a common electrode that is continuous in the area closer to the substrate than the bottom of the groove. The piezoelectric elements 21 are then polarized and attached to the substrate 10 using an adhesive or the like. Then, the FPC 70 is bonded to the external electrode 231 serving as the individual electrode, and the manifold 40 and the frame 60 are bonded. The nozzles 51 are arranged facing the pressure chambers 31 , and the nozzle plate 50 is bonded, thereby completing the inkjet head 1 .

[0043] Below, refer to Figure 6 An example of an inkjet recording apparatus 100 including the inkjet head 1 will be described. The inkjet recording apparatus 100 includes a housing 111 , a medium supply unit 112 , an image forming unit 113 , a medium discharge unit 114 , a transport device 115 , and a control unit 116 .

[0044] The inkjet recording device 100 is a liquid ejecting device that ejects liquid such as ink while transporting a printing medium, such as paper P, as an ejection object, along a predetermined transport path A from a medium supply unit 112 through an image forming unit 113 to a medium discharge unit 114, thereby performing image formation processing on the paper P.

[0045] The housing 111 constitutes the outer shell of the inkjet recording apparatus 100. A discharge port for discharging the paper P to the outside is provided at a predetermined position of the housing 111.

[0046] The medium supply unit 112 includes a plurality of paper feed cassettes and is configured to be able to stack and hold a plurality of sheets of paper P of various sizes.

[0047] The medium discharge unit 114 includes a paper discharge tray configured to hold the paper P discharged from the discharge port.

[0048] The image forming section 113 includes a support portion 117 that supports the paper P, and a plurality of head units 130 that are arranged to face each other above the support portion 117 .

[0049] The support portion 117 includes a conveyor belt 118 provided in an endless shape in a predetermined area where image formation is performed, a support plate 119 supporting the conveyor belt 118 from the rear side, and a plurality of belt rollers 120 provided on the rear side of the conveyor belt 118 .

[0050] During image formation, the support portion 117 supports the paper P on the holding surface, which is the upper surface of the conveyor belt 118 , and the belt roller 120 rotates to move the conveyor belt 118 at a predetermined timing, thereby conveying the paper P downstream.

[0051] The head unit 130 includes a plurality of (four-color) inkjet heads 1 , ink tanks 132 as liquid tanks mounted on the respective inkjet heads 1 , connection channels 133 connecting the inkjet heads 1 and the ink tanks 132 , and a supply pump 134 .

[0052] In this embodiment, the inkjet heads 1 for four colors, cyan, magenta, yellow, and black, and the ink tanks 132 for storing the inks of the respective colors are provided. The ink tanks 132 are connected to the inkjet heads 1 via connection channels 133 .

[0053] Furthermore, a negative pressure control device, such as a pump (not shown), is connected to the ink tank 132. The negative pressure control device controls the negative pressure within the ink tank 132 according to the hydraulic head value between the inkjet head 1 and the ink tank 132, thereby forming a meniscus of a predetermined shape in the ink supplied to each nozzle 51 of the inkjet head 1.

[0054] The supply pump 134 is a liquid delivery pump, for example, a piezoelectric pump. The supply pump 134 is disposed in the supply flow path. The supply pump 134 is connected to the drive circuit of the control unit 116 via wiring and is configured to be controlled by the CPU (Central Processing Unit). The supply pump 134 supplies liquid to the inkjet head 1.

[0055] The transport device 115 transports the paper P along a transport path A from the medium supply unit 112 through the image forming unit 113 to the medium discharge unit 114 . The transport device 115 includes a plurality of guide plate pairs 121 arranged along the transport path A and a plurality of transport rollers 122 .

[0056] Each of the plurality of guide plate pairs 121 includes a pair of plate members disposed opposite to each other with the paper P being transported interposed therebetween, and guides the paper P along the transport path A.

[0057] The transport roller 122 is driven to rotate under the control of the control unit 116 , thereby conveying the paper P downstream along the transport path A. Note that sensors for detecting the transport status of the paper are disposed at various locations on the transport path A.

[0058] The control unit 116 includes: a control circuit such as a CPU serving as a controller; a ROM (Read Only Memory) for storing various programs, etc.; a RAM (Random Access Memory) for temporarily storing various variable data, image data, etc.; and an interface unit for inputting and outputting data from and to the outside.

[0059] In the inkjet recording device 100 configured as described above, when, for example, the interface detects a print instruction from a user operating the operation input unit, the control unit 116 drives the transport device 115 to transport the paper P and outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 1. In the inkjet recording device 100, the image signal corresponding to the image data transmits a drive signal to the driver IC, which applies a drive voltage to the internal electrodes 221 and 222. This selectively drives the piezoelectric element 21, causing it to vibrate longitudinally in the stacking direction. This changes the volume of the pressure chamber 31, causing ink to be ejected from the nozzle 51, thereby forming an image on the paper P held on the transport belt 118. Furthermore, in the liquid ejection operation, the control unit 116 drives the supply pump 134 to supply ink from the ink tank 132 to the common chamber 32 of the inkjet head 1.

[0060] According to the inkjet head 1 and inkjet recording device 100 involved in the above-mentioned embodiment, since the piezoelectric element 21 has a step portion 25 on the surface where the FPC 70 is set, a part of the FPC 70 can be arranged on the step portion 25. Therefore, even if the insulating cover layer 75 of the FPC 70 is thick, the FPC 70 can be installed without generating an invalid space, and the invalid space can be eliminated, and as a result, it can be reduced inexpensively. In addition, by setting the step shape having the retreat surface 26 along the stacking direction, it is less susceptible to the influence of the accuracy, warping, etc. of the PZT itself compared to the case of being processed into a cone shape, and the accuracy of the electrode removal portion is high. It should be noted that since the piezoelectric element 21 is a stacked piezoelectric actuator, the individual electrode is also part of the external electrode. Therefore, even if a step is set, it does not directly affect the drive, and thus does not affect the drive, so there is no effect on the function of the piezoelectric element 21.

[0061] It should be noted that the present invention is not limited to the above-described embodiment itself, and in the implementation stage, the constituent elements may be modified and embodied within the scope not departing from the gist of the invention.

[0062] For example, in the above embodiment, an example of welding the external electrode 231 and the electrode layer 72 is shown, but the present invention is not limited thereto. Figure 7As shown, bonding may be performed using an anisotropic conductive adhesive 29 such as ACF (anisotropic conductive film) 76. In this embodiment, by positioning the insulating cover layer 75 and the adhesive layer 74 so as to avoid the bonding surface 27, reliable mounting can also be achieved.

[0063] In addition, as another embodiment, Figure 8 As shown, an adhesive 28 may be injected between the surface of the insulating cover layer 75 of the FPC 70 and the retreat surface 26, thereby bonding the surface of the insulating cover layer 75 of the FPC 70 and the retreat surface 26 together with the adhesive 28. According to this embodiment, since the FPC 70 is bonded at multiple locations along the longitudinal direction, the mounting portion can be reinforced and peeling can be suppressed.

[0064] In addition, although the stacked piezoelectric element 21 is exemplified in the above embodiment, a single-layer piezoelectric body may be used. For example, as another embodiment, Figure 9 The illustrated liquid ejecting head 400 includes a piezoelectric component 420, a vibration plate 430, a manifold 440 forming a plurality of pressure chambers 431, a nozzle plate 450 having a plurality of nozzles 451, and an FPC 470. In this embodiment, the polarization direction of the piezoelectric component 420 is arranged orthogonal to the strain direction, and the FPC 470 is bonded to a side surface extending in the strain direction.

[0065] Specifically, the side surface of the piezoelectric component 420 on one end in the polarization direction has a step 425. It includes a bonding surface 427 that bonds to the FPC 470 via this step 425, and a setback surface 426 located on the other side of the step 425 and set back from the FPC 470 relative to the bonding surface 427. In the side surface on the one end in the polarization direction, an external electrode 4231, serving as an individual electrode, is formed in the region facing the pressure chamber 431. The bonding surface 427 is located on the side facing the pressure chamber 431, while the setback surface 426 is located on the side opposite the pressure chamber 431. The side surface on the other end in the polarization direction of the piezoelectric component 420 has an external electrode 4232, serving as a common electrode. The portion of the side surface on the other end in the polarization direction, opposite the pressure chamber 431, constitutes a fixing portion for fixing to the manifold 440.

[0066] In this embodiment, a step 425 is provided on the side surface of the piezoelectric component 420, which sets a portion of the individual electrode 231 side bonded to the FPC 470 back from the bonding surface 427. This also eliminates dead space and enables miniaturization. It should be noted that in the case of a single-layer piezoelectric body, the external electrode serves as the driving electrode. However, by forming the step 425 only in a portion where no electrodes are arranged, such as the portion fixed to the manifold 440, the same effects as those of the above-described embodiment can be achieved.

[0067] In addition, the specific structure of the piezoelectric element 21, the shape of the flow path, the structure of various components including the manifold 40, the nozzle plate 50, and the frame 60, and the positional relationship are not limited to the above examples and can be changed appropriately. In addition, the arrangement of the nozzles 51 and the pressure chambers 31 is not limited to the above. For example, the nozzles 51 can also be arranged in two or more rows. In addition, a dummy chamber can also be formed between multiple pressure chambers 31. In addition, an example is shown in which the piezoelectric element 21 has a dummy layer 24 at both ends in the stacking direction, but it is not limited to this. The dummy layer 24 can also be provided only on one side of the piezoelectric element 21, or the piezoelectric element 21 can also be configured without a dummy layer 24.

[0068] For example, the liquid to be discharged is not limited to printing ink, and may be a device that discharges a liquid containing conductive particles for forming a wiring pattern of a printed wiring board.

[0069] In addition, in the above embodiment, an example of the inkjet head 1 being used in a liquid ejecting device such as an inkjet recording device is shown, but it is not limited to this. For example, it can also be used in 3D printers, industrial manufacturing machinery, and medical purposes, and can achieve miniaturization, lightness, and low cost.

[0070] According to at least one of the embodiments described above, a liquid ejecting head and a liquid ejecting device using a lead-free piezoelectric material can be provided.

[0071] In addition, although several embodiments of the present invention have been described, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the scope of the invention. These embodiments and their variations are included in the scope and spirit of the invention and are also included in the invention described in the claims and their equivalents.

[0072] [Description of Reference Numerals]

[0073] 1: Inkjet head; 10: Base; 20: Piezoelectric component; 21: Piezoelectric element; 22: Groove; 23: Piezoelectric layer; 24: Dummy layer; 25: Step portion; 26: Retreat surface; 27: Joint surface; 28: Discharge nozzle; 30: Vibration plate; 31: Pressure chamber; 32: Common chamber; 33: Opening portion; 34: Guide flow path; 35: Ink flow path; 40: Manifold; 41: Frame portion; 42: Partition wall portion; 43: Guide wall; 50: Nozzle plate; 51: Nozzle; 60: Frame; 70: Wiring substrate; 71: Base layer; 72: Electrode layer; 73: Solder plating layer; 74: Adhesive layer; 75: Insulation covering layer; 100: Inkjet recording device; 111: Housing; 112: Medium supply unit; 113: Image forming unit; 114: Medium discharge unit; 115: Conveying device; 116: Control unit; 117: Support unit; 118: Conveyor belt; 119: Support plate; 120: Belt roller; 121: Guide plate pair; 122: Conveying roller; 130: Head unit; 132: Ink tank; 133: Connecting flow path; 134: Supply pump; 201: Stacked piezoelectric body; 221, 222: Internal electrodes; 231, 232: External electrodes; 301: Vibrating portion; 400: Liquid ejector; 420: Piezoelectric component; 423: Piezoelectric layer; 425: Step; 430: Vibrating plate; 431: Pressure chamber; 440: Manifold; 450: Nozzle plate; 451: Nozzle; 470: Wiring substrate (FPC).

Claims

1. A liquid spray head comprising: A flexible wiring substrate comprising an electrode layer and a cover layer, wherein the electrode layer comprises a first region and a second region, and the cover layer is stacked on the second region of the electrode layer; as well as A plurality of piezoelectric elements are arranged opposite to the first region of the electrode layer of the flexible wiring substrate and have a step, and have: a bonding surface connected to the first region of the electrode layer; and a setback surface that is set back from the flexible wiring substrate relative to the bonding surface.

2. The liquid ejecting head according to claim 1, wherein The flexible wiring substrate is electrically and mechanically connected to the bonding surface of the piezoelectric element via solder or an anisotropic conductive adhesive.

3. The liquid ejecting head according to claim 1 or 2, wherein: The piezoelectric element includes a plurality of stacked piezoelectric layers. The liquid ejecting head includes a pressure chamber whose volume changes due to vibration of the piezoelectric element, and a nozzle communicating with the pressure chamber. Liquid is ejected from the nozzle communicating with the pressure chamber due to the change in the volume of the pressure chamber.

4. The liquid ejecting head according to claim 1, wherein The escape surface is provided at a location different from a location where an internal electrode is formed in the piezoelectric element, and a depth dimension of a step between the bonding surface and the escape surface is greater than a difference in position between the electrode layer and the cover layer of the flexible wiring substrate.

5. The liquid ejecting head according to claim 1, wherein The retreat surface and the surface of the cover layer of the flexible wiring substrate are bonded together by an adhesive. The liquid ejecting head according to claim 3 , wherein: The piezoelectric layer is formed of a PZT-based or lead-free KNN-based piezoelectric material in a thin plate shape.

7. The liquid ejecting head according to claim 3, wherein The number of stacked piezoelectric layers is 50 or less, the thickness of each layer is 10 μm to 40 μm, and the product of the thickness and the total number of stacked layers is less than 1000 μm.

8. The liquid ejecting head according to claim 1, wherein The liquid ejecting head further includes a nozzle plate. The nozzle plate is formed in a plate shape with a thickness of 10 μm to 100 μm and made of a metal or resin material.

9. The liquid ejecting head according to claim 1, wherein The flexible wiring substrate further includes a base layer, and the base layer is formed of polyimide in a sheet shape.

10. The liquid ejecting head according to claim 1, wherein The flexible wiring board further includes a solder plating layer, and the solder plating layer is solder-plated to have a thickness of 3 μm to 10 μm.

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