Liquid dispensing head, method for manufacturing a liquid dispensing head, and liquid dispensing device

Abstract

This reduces the impact on discharge performance caused by variations in processing and misalignment between internal electrodes. [Solution] The piezoelectric member 40 has at least two stepped portions 45 on the bonding surface 40a with the diaphragm member. If the stacking direction of the multiple internal electrodes 51 is defined as the height direction and the direction in which the multiple electrode stacking blocks 44 are aligned is defined as the width direction, then the adjacent ends 45a and 45b of the two stepped portions 45 are located within the width direction range L of the portion where all the internal electrodes 51 of the electrode stacking block 44 overlap in the height direction. The height dimension Ha of the two stepped portions 45 is less than or equal to the height dimension Hb from the bonding surface 40a to the internal electrode 51 furthest from the bonding surface 40a.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, a method for manufacturing the liquid ejection head, and a liquid ejection device.

Background Art

[0002] As a liquid ejection head mounted on an inkjet type image forming apparatus, a piezo type liquid ejection head that discharges liquid by deforming a piezoelectric member by energization is known.

[0003] The piezoelectric member is configured by cutting, for example, a laminate of a piezoelectric layer and internal electrodes alternately laminated to a predetermined width by blade dicing or the like. However, in such a manufacturing method, as the number of laminations of the piezoelectric layer and the internal electrodes increases, variations in processing due to cutting tend to occur, so there is a risk that the ejection performance of the liquid ejection head will be affected by the processing variations.

[0004] Also, in Patent Document 1 (Japanese Patent Laid-Open No. 11-179898), a method for manufacturing a piezoelectric member without cutting has been proposed. In this method, since internal electrodes formed in a predetermined size are laminated in advance, variations due to cutting do not occur, but there is a risk that variations due to misalignment during lamination of the internal electrodes will occur. [[ID=2(1]]

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to provide a liquid ejection head capable of reducing the influence on ejection performance due to processing variations and variations in the positions of internal electrodes.

Means for Solving the Problems

[0006] To solve the above problems, the present invention provides a liquid discharge head comprising: a plurality of nozzles for discharging liquid; a liquid chamber member having a plurality of individual liquid chambers individually communicating with the plurality of nozzles; and a piezoelectric actuator having a piezoelectric member for pressurizing the liquid in the individual liquid chambers via a diaphragm member constituting a part of the individual liquid chambers, wherein the piezoelectric member has a plurality of internal electrodes stacked for each of the plurality of individual liquid chambers, and a plurality of piezoelectric layers stacked across the plurality of individual liquid chambers so as to sandwich the internal electrodes, and the piezoelectric actuator has an individual electrode connected to the internal electrode for each of the plurality of electrode stacking blocks consisting of the plurality of internal electrodes stacked for each of the plurality of individual liquid chambers, and the plurality of electrical The piezoelectric member has a common electrode that is connected to the internal electrode in common across the electrode stacking block, the individual electrodes are separated by dividing grooves for each of the plurality of electrode stacking blocks, and the bonding surface of the piezoelectric member with the diaphragm member has at least two stepped portions, and when the stacking direction of the plurality of internal electrodes is defined as the height direction and the direction in which the plurality of electrode stacking blocks are lined up is defined as the width direction, the adjacent ends of the two stepped portions are located within the width direction of the portion in which all of the internal electrodes of the electrode stacking block overlap in the height direction, and the height dimension of the two stepped portions is less than or equal to the height dimension from the bonding surface to the internal electrode furthest from the bonding surface. [Effects of the Invention]

[0007] According to the present invention, the impact on discharge performance due to variations in processing and variations in the position of internal electrodes can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the overall configuration of an inkjet-type image forming apparatus, which is an example of a liquid ejection device to which the present invention is applied. [Figure 2] This is a block diagram showing a control system for an image forming apparatus according to the first embodiment of the present invention. [Figure 3] This is a plan view of a head unit according to the first embodiment of the present invention. [Figure 4]This is a perspective view of the liquid dispensing head according to the first embodiment of the present invention. [Figure 5] This is a cross-sectional view of the liquid dispensing head according to the first embodiment of the present invention, taken in the Y direction in Figure 4. [Figure 6] This is a cross-sectional view of the liquid dispensing head according to the first embodiment of the present invention, taken in the X direction in Figure 4. [Figure 7] Figure 6 is a plan view of a piezoelectric member according to the first embodiment of the present invention, as seen from above. [Figure 8] This is an enlarged cross-sectional view showing an electrode stacking block according to the first embodiment of the present invention. [Figure 9] This graph shows the relationship between the widthwise position of the electrode stacking block according to the first embodiment of the present invention and the amount of drive displacement of the piezoelectric actuator at each widthwise position. [Figure 10] This is an enlarged cross-sectional view showing an electrode stacking block according to a second embodiment of the present invention. [Figure 11] This is a plan view showing an example of a serial-type liquid dispensing head. [Figure 12] This is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus to which the present invention can be applied. [Figure 13] This is a cross-sectional view showing an example of a piezoelectric component. [Figure 14] This figure shows an example of a method for manufacturing a piezoelectric component. [Figure 15] This figure shows another example of a method for manufacturing piezoelectric components. [Modes for carrying out the invention]

[0009] The present invention will be described below with reference to the attached drawings. In each drawing used to explain the present invention, components such as members and parts having the same function or shape will be denoted by the same reference numerals as far as possible to distinguish them, and their description will be omitted after they have been described once.

[0010] <Overall configuration of the image forming apparatus> FIG. 1 is a schematic diagram showing the overall configuration of an inkjet type image forming apparatus 100 which is an example of a liquid ejection apparatus to which the present invention is applied.

[0011] First, while referring to FIG. 1, the overall configuration of the inkjet type image forming apparatus 100 according to the first embodiment of the present invention will be described.

[0012] As shown in FIG. 1, the image forming apparatus 100 according to the first embodiment of the present invention includes a sheet supply unit 1 that supplies a sheet S on which an image is to be formed, a conveyance unit 2 that conveys the sheet S supplied from the sheet supply unit 1, an image forming unit 3 that forms an image on the sheet S, a drying unit 4 that dries the sheet S, and a sheet recovery unit 5 that recovers the sheet S on which the image has been formed.

[0013] The sheet supply unit 1 is provided with a supply roller 11 around which a long sheet S is wound in a roll shape, and a tension adjustment mechanism 12 that adjusts the tension applied to the sheet S. The supply roller 11 is configured to be rotatable in the direction of the arrow in FIG. 1, and when the supply roller 11 rotates, the sheet S is fed out. The tension adjustment mechanism 12 has a plurality of adjustment rollers that span the sheet S and apply tension. By changing the distance between the adjustment rollers, the tension of the sheet S is adjusted, and the sheet S is supplied with a constant tension.

[0014] The conveyance unit 2 is provided with a plurality of conveyance rollers 15 as conveyance means for conveying the sheet S. When the sheet S is supplied from the sheet supply unit 1 to the conveyance unit 2, the sheet S is conveyed to the image forming unit 3 by the plurality of conveyance rollers 15.

[0015] The image forming unit 3 is provided with a head unit 13 having a plurality of liquid ejection heads that eject liquid ink onto the sheet S, and a platen 14 as a sheet support member that supports the conveyed sheet S. The sheet S conveyed by the conveyance roller 15 passes under the head unit 13 while being supported by the platen 14. At this time, ink is ejected from the head unit 13 onto the sheet S, and an image is formed on the sheet S.

[0016] In the drying unit 4, a heating drum 16 or the like as a heating means for heating the sheet S is provided. The heating drum 16 is a cylindrical heating member in which a heating source such as a halogen heater is housed inside. After an image is formed on the sheet S, when the sheet S is conveyed to the drying unit 4, the sheet S is heated by contacting the outer peripheral surface of the heating drum 16, and the sheet S is dried. In addition, as the heating means for heating the sheet S, in addition to the contact-type heating means such as the heating drum 16, a non-contact-type heating means such as a hot air generator for blowing hot air onto the sheet S may be used.

[0017] In the sheet collection unit 5, a collection roller 17 for winding and collecting the sheet S and a tension adjustment mechanism 18 for adjusting the tension applied to the sheet S are provided. The collection roller 17 is configured to be rotatable in the direction of the arrow in FIG. 1, and when the collection roller 17 rotates, the sheet S is wound up in a roll shape and collected. The tension adjustment mechanism 18 has a plurality of adjustment rollers, similar to the tension adjustment mechanism 12 of the sheet supply unit 1. By changing the distance between the adjustment rollers, the tension of the sheet S is adjusted, and the sheet S is wound up and collected by the collection roller 17 with a constant tension.

[0018] FIG. 2 is a block diagram showing the control system of the image forming apparatus 100 according to the first embodiment of the present invention.

[0019] As shown in FIG. 2, the image forming apparatus 100 according to the first embodiment of the present invention includes, in addition to the sheet supply unit 1, the conveyance unit 2, the image forming unit 3, the drying unit 4, and the sheet collection unit 5, a control unit 6 for controlling these units.

[0020] The control unit 6 is an information processing device such as a PC (Personal Computer). The control unit 6 generates image data of the image to be formed on the sheet S, and also controls various operations of the sheet supply unit 1, transport unit 2, image forming unit 3, drying unit 4, and sheet recovery unit 5. For example, the control unit 6 controls the ink ejection operation of the head unit 13, the rotation speed of the supply roller 11, recovery roller 17, and each transport roller 15, and the heating temperature of the heating drum 16. Furthermore, an image is formed on the sheet S by ejecting ink from the head unit 13 onto the sheet S based on the image data generated by the control unit 6.

[0021] <Head unit configuration> Next, the configuration of the head unit 13 according to the first embodiment of the present invention will be described based on Figure 3.

[0022] Figure 3 is a plan view of the head unit 13 according to the first embodiment of the present invention.

[0023] As shown in Figure 3, the head unit 13 according to the first embodiment of the present invention includes a plurality of head arrays 19A, 19B, 19C, and 19D arranged in the conveying direction Y of the sheet S. These head arrays 19A, 19B, 19C, and 19D are full-line type head arrays that eject liquids (inks) of different colors such as yellow, magenta, cyan, and black. Note that the color of the liquid ejected by the head arrays and the number of head arrays provided in the head unit 13 are not limited to these and can be changed as appropriate.

[0024] Each of the multiple head arrays 19A, 19B, 19C, and 19D comprises multiple liquid dispensing heads 20 for dispensing liquid and a base member 10 for holding the multiple liquid dispensing heads 20. In this case, the liquid dispensing heads 20 are arranged in a staggered pattern toward the conveying direction A of the sheet S, but the arrangement of the liquid dispensing heads 20 is not limited to this and can be changed as appropriate.

[0025] As shown in Figure 3, when the sheet S is transported in the direction of arrow A (transport direction A) and reaches a position facing the head unit 13 (image formation position), liquid (ink) is ejected from the liquid ejection head 20 onto the transported sheet S. As a result, an image is sequentially formed on the sheet S.

[0026] <Configuration of the liquid dispensing head unit> Next, the configuration of the liquid discharge head 20 according to the first embodiment of the present invention will be described.

[0027] Figure 4 is an external perspective view of the liquid discharge head 20 according to the first embodiment of the present invention.

[0028] As shown in Figure 4, the liquid discharge head 20 according to the first embodiment of the present invention comprises a nozzle plate 21, a liquid chamber member 22, a diaphragm member 23, a common flow path member 24, a cover member 25, and the like. The nozzle plate 21, liquid chamber member 22, diaphragm member 23, and common flow path member 24 are stacked and joined in this order. The cover member 25 is a member that covers and protects the drive IC that controls the driving of the piezoelectric member described later, as well as flexible wiring members connected to the piezoelectric member. The common flow path member 24 is provided with a supply port 8 for supplying liquid from a supply tank and a recovery port 9 for sending liquid to a recovery tank.

[0029] The liquid discharge head 20 according to the first embodiment of the present invention is formed as a whole in a longitudinal block shape extending in the X direction in Figure 4. The X, Y, and Z directions in Figure 4 represent the three-dimensional coordinate axes of the liquid discharge head 20 according to the first embodiment of the present invention. In this case, the X direction is parallel to the longitudinal direction of the liquid discharge head 20, and the Y direction is perpendicular to the X direction when the liquid discharge head 20 is viewed from above in the Z direction. The Z direction is perpendicular to both the X and Y directions. The X, Y, and Z directions in other drawings also represent the same directions as in Figure 4.

[0030] Figure 5 is a cross-sectional view of the liquid discharge head 20 according to the first embodiment of the present invention, cut in the Y direction in Figure 4.

[0031] As shown in Figure 5, the nozzle plate 21 has a nozzle surface 21a through which multiple nozzles 30 open. In Figure 5, only one nozzle 30 is shown, but multiple nozzles 30 are arranged in a row along the longitudinal direction of the liquid discharge head 20 (the X direction in Figure 4).

[0032] The liquid chamber member 22 has a plurality of individual liquid chambers 31 that communicate individually with a plurality of nozzles 30, a plurality of individual supply channels 32 that communicate individually with the plurality of individual liquid chambers 31, one or more intermediate supply channels 33 that communicate with one or more individual supply channels 32, a plurality of individual recovery channels 34 that communicate individually with the plurality of individual liquid chambers 31, and one or more intermediate recovery channels 35 that communicate with one or more individual recovery channels 34.

[0033] The common flow channel member 24 has a common supply channel 36 that communicates with a plurality of individual supply channels 32 via one or more intermediate supply channels 33, and a common recovery channel 37 that communicates with a plurality of individual recovery channels 34 via one or more intermediate recovery channels 35. The common supply channel 36 communicates with the supply port 8 (see Figure 4), and the common recovery channel 37 communicates with the recovery port 9 (see Figure 4). Therefore, when liquid is supplied from the supply port 8 into the common supply channel 36, the liquid is supplied from the common supply channel 36 through the intermediate supply channels 33 and individual supply channels 32 into the individual liquid chambers 31. The liquid in the individual liquid chambers 31 is then discharged from the recovery port 9 through the individual recovery channels 34, intermediate recovery channels 35 and common recovery channel 37.

[0034] The diaphragm member 23 is a deformable member that constitutes a part (wall surface) of the individual liquid chamber 31. By joining the diaphragm member 23 to the liquid chamber member 22, the grooves constituting the individual liquid chamber 31 are sealed by the diaphragm member 23, and a deformable wall surface is formed by the diaphragm member 23 at the sealed portion. In addition, a piezoelectric actuator 26, which serves as a driving means for deforming the diaphragm member 23, is joined to the portion of the diaphragm member 23 corresponding to the individual liquid chamber 31.

[0035] The piezoelectric actuator 26 includes a piezoelectric member 40 and a base member 41 to which the piezoelectric member 40 is joined. The piezoelectric member 40 is electrically connected to a drive IC via a flexible wiring member. When a drive voltage is applied to the piezoelectric member 40 by a drive signal emitted from the drive IC, the piezoelectric member 40 expands and contracts in the vertical direction as shown in Figure 5, causing liquid to be discharged from the nozzle 30. Specifically, first, when the piezoelectric member 40 contracts, the piezoelectric member 40 pulls the diaphragm member 23, causing the volume of the individual liquid chamber 31 to expand and liquid to flow into the individual liquid chamber 31. Next, when the piezoelectric member 40 extends, the piezoelectric member 40 pushes the diaphragm member 23, causing the volume of the individual liquid chamber 31 to contract, pressurizing the liquid in the individual liquid chamber 31 and causing it to be discharged from the nozzle 30.

[0036] Furthermore, any liquid that is not discharged from the nozzle 30 passes through the nozzle 30, then through the individual recovery channel 34, the intermediate recovery channel 35, and the common recovery channel 37, and is sent from the recovery port 9 to the recovery tank for recovery. The liquid recovered in the recovery tank is then sent to the supply tank, and from the supply tank it is again supplied to the individual liquid chamber 31 of the liquid discharge head 20. Thus, in the image forming apparatus 100 according to the first embodiment of the present invention, the liquid recovered in the recovery tank is circulated by being sent again from the supply tank to the liquid discharge head 20.

[0037] <Challenges in the manufacturing process of piezoelectric components> Here, we will explain the challenges in manufacturing piezoelectric components for piezoelectric actuators.

[0038] As shown in Figure 13, the piezoelectric member 40 is constructed by alternately stacking piezoelectric layers 50 and internal electrodes 51. The piezoelectric member 40 also has a plurality of piezoelectric blocks 42 separated by dividing grooves 43 so that each of the plurality of individual liquid chambers 31 expands and contracts independently. As these piezoelectric blocks 42 expand and contract independently of each other, the liquid in each individual liquid chamber 31 is pressurized, and the liquid is discharged from the nozzle 30.

[0039] One method for manufacturing such a piezoelectric member 40 is to cut a piezoelectric member 40, in which piezoelectric layers 50 and internal electrodes 51 are alternately stacked, to a predetermined width by blade dicing or the like, as shown in Figure 14, thereby forming a plurality of piezoelectric blocks 42 separated by dividing grooves 43.

[0040] However, as the number of layers of piezoelectric layer 50 and internal electrode 51 increases, the depth of the cut (depth of the dividing groove 43) when cutting the piezoelectric block 42 becomes deeper, which can easily lead to variations in processing. Furthermore, if the widths of the internal electrodes 51 differ due to variations in processing, it will affect the displacement (expansion and contraction) of the piezoelectric block 42, which may cause variations in the discharge performance of the liquid discharge head.

[0041] Another manufacturing method, as shown in Figure 15, involves stacking internal electrodes 51 that have been pre-formed to a predetermined width. However, in this case, there is a risk of variations occurring due to misalignment when stacking the internal electrodes 51.

[0042] Therefore, the present invention proposes a liquid discharge head configuration that can reduce the impact on discharge performance due to variations in processing and variations in the positions of the internal electrodes 51. The features of the present invention will be described below using the configuration according to the first embodiment of the present invention as an example.

[0043] <Structure of the liquid dispensing head> Figure 6 is a cross-sectional view of the liquid discharge head 20 according to the first embodiment of the present invention, cut in the direction of X in Figure 4.

[0044] As shown in Figure 6, in the liquid discharge head 20 according to the first embodiment of the present invention, the piezoelectric member 40 comprises a plurality of electrode stacking blocks 44, each consisting of a plurality of internal electrodes 51 stacked for each individual liquid chamber 31. The internal electrodes 51 constituting the plurality of electrode stacking blocks 44 are sandwiched between a plurality of piezoelectric layers 50 that are commonly arranged across the plurality of individual liquid chambers 31, thereby forming an expandable and contractible piezoelectric member 40. That is, the piezoelectric member 40 according to the first embodiment of the present invention alternately has a plurality of internal electrodes 51 that are individually stacked for each of the plurality of individual liquid chambers 31 and a plurality of piezoelectric layers 50 that are commonly stacked across the plurality of individual liquid chambers 31.

[0045] The piezoelectric layer 50 is made of, for example, lead zirconate titanate (PZT) with a thickness of 10 to 50 μm. The internal electrodes 51 are made of, for example, silver palladium (AgPd) with a thickness of several μm. The internal electrodes 51 are drawn out to opposite end faces of the piezoelectric member 40 and electrically connected to individual electrodes provided on one end face and a common electrode provided on the other end face.

[0046] Figure 7 is a plan view of the piezoelectric member 40 according to the first embodiment of the present invention, as seen from above in Figure 6.

[0047] As shown in Figure 7, the individual electrodes 52 are formed by dividing each electrode stacking block 44 individually by dividing grooves 43. On the other hand, the common electrode 53 is not divided for each electrode stacking block 44, but is provided in common across multiple electrode stacking blocks 44. In the first embodiment of the present invention, since the internal electrodes 51 are stacked individually for each individual liquid chamber 31, it is not necessary to divide the internal electrodes 51 into predetermined widths by dividing grooves 43, as in the example in Figure 14. For this reason, the dividing grooves 43 only need to be provided at least on the end face of the piezoelectric member 40 on the individual electrode 52 side in order to divide the individual electrodes 52, and do not need to be provided continuously from the end face on the individual electrode 52 side to the end face on the common electrode 53 side.

[0048] Furthermore, a flexible wiring member on which a drive IC is mounted is connected to each individual electrode 52. Therefore, when a drive voltage is applied to the internal electrode 51 by a drive signal emitted from the drive IC, the expansion and contraction of the piezoelectric layer 50 is controlled for each electrode stacking block 44. As a result, the expansion and contraction of the piezoelectric layer 50 is controlled for each electrode stacking block 44 based on the drive signal from the drive IC, and liquid is discharged from the desired nozzle 30.

[0049] Incidentally, the amount of drive displacement (expansion / contraction) in a piezoelectric actuator depends on the sum of the capacitances of the stacked internal electrodes 51 (sum in the stacking direction). Therefore, the more internal electrodes 51 are stacked, the larger the drive displacement tends to be, and conversely, the fewer internal electrodes 51 are stacked, the smaller the drive displacement tends to be. In this regard, in the first embodiment of the present invention, since the same number of internal electrodes 51 that have been formed in advance to a predetermined size are stacked to constitute an electrode stacking block 44, the sum of the capacitances of the internal electrodes 51 in each electrode stacking block 44 is basically the same.

[0050] However, in reality, as shown in Figure 6, the sizes of the stacked internal electrodes 51 differ to some extent, and the internal electrodes 51 are misaligned to some extent. As a result, within a single electrode stacking block 44, there are areas with a relatively large number of stacked internal electrodes 51 and areas with a relatively small number of stacked internal electrodes 51. That is, in the area where all the internal electrodes 51 of the electrode stacking block 44 overlap, the number of stacked internal electrodes 51 is relatively large, but in the area where the internal electrodes 51 are misaligned and protrude, the number of stacked internal electrodes 51 is relatively small. Therefore, depending on how the internal electrodes 51 are misaligned, the ratio of areas with a large number of stacked internal electrodes 51 to areas with a small number of stacked internal electrodes 51 changes, which in turn changes the amount of drive displacement for each electrode stacking block 44, resulting in variations in discharge performance.

[0051] Therefore, in the first embodiment of the present invention, in order to suppress variations in discharge performance due to misalignment of the internal electrodes 51, a stepped portion 45 is provided on the joining surface 40a of the piezoelectric member 40 joined to the diaphragm member 23, as shown in Figure 6. The configuration and function of the stepped portion 45 will be described in detail below. In the following description, the stacking direction of the piezoelectric layer 50 and the internal electrodes 51 (Z direction in Figure 6) will be referred to as the "height direction," and the direction in which the multiple individual liquid chambers 31 and the multiple electrode stacking blocks 44 are arranged (X direction in Figure 6) will be referred to as the "width direction."

[0052] Figure 8 is an enlarged cross-sectional view showing the electrode stacking block 44 according to the first embodiment of the present invention.

[0053] As shown in Figure 8, the two stepped portions 45 are positioned apart from each other at locations corresponding to both sides in the width direction of the electrode stacking block 44. In this case, the two stepped portions 45 are composed of recesses with a rectangular cross-section (rectangular or square cross-section), but the cross-sectional shape of the recesses constituting the stepped portions 45 is not limited to a rectangular shape; other shapes are also possible.

[0054] It should be noted that the adjacent ends 45a and 45b of the two stepped sections 45 are located within the range indicated by the symbol L in Figure 8. This range indicated by the symbol L represents the widthwise range of the portion where all the internal electrodes 51 of the electrode stacking block 44 overlap in the height direction. In other words, the adjacent ends 45a and 45b of the two stepped sections 45 are located within the maximum stacking range L in the widthwise direction, where all the internal electrodes 51 overlap in the height direction and the number of stacked internal electrodes 51 is maximized.

[0055] Within the maximum stacking range L, the number of stacked internal electrodes 51 is maximized, and therefore the total capacitance of the stacked internal electrodes 51 (sum in the stacking direction) is also maximized, ensuring a large amount of drive displacement for the piezoelectric actuator. However, depending on how the internal electrodes 51 are misaligned, the width of the maximum stacking range L changes, and thus the effective drive range in which the piezoelectric actuator can be effectively driven also changes. For this reason, in the first embodiment of the present invention, in order to suppress changes in the effective drive range due to misalignment of the internal electrodes 51, the adjacent ends 45a and 45b of the two stepped portions 45 are placed within the maximum stacking range L so that the effective drive range becomes a specific range (a certain range).

[0056] Figure 9 is a graph showing the relationship between the widthwise position of the electrode stacking block 44 according to the first embodiment of the present invention and the amount of drive displacement of the piezoelectric actuator at each widthwise position.

[0057] As shown in Figure 9, the amount of drive displacement of the piezoelectric actuator tends to decrease as it approaches the ends 45a and 45b of the two stepped sections 45. That is, the amount of drive displacement of the piezoelectric actuator is mainly obtained within the range from the end 45a of one stepped section 45 to the end 45b of the other stepped section 45. Therefore, by determining the positions of the ends 45a and 45b, it is possible to specify the drive range of the piezoelectric actuator. Accordingly, by arranging the ends 45a and 45b of the two stepped sections 45 within the maximum stacking range L, the effective drive range of the piezoelectric actuator can be determined to a specific range.

[0058] Thus, in the first embodiment of the present invention, by arranging the ends 45a and 45b of the two stepped portions 45 within the maximum stacking range L, the effective driving range of the piezoelectric actuator can be determined to a specific range, thereby suppressing changes in the effective driving range due to displacement of the internal electrodes 51. Furthermore, since the expansion and contraction of the piezoelectric layer 50 is transmitted to the diaphragm member 23 via a projection 46 (see Figure 8) formed between the two stepped portions 45, the range of expansion and contraction transmitted to the diaphragm member 23 is also determined by specifying the widthwise dimension of this projection 46. As a result, the amount and range of deformation of the diaphragm member 23 that deforms due to the driving of the piezoelectric actuator are determined, so that variations in discharge performance for each electrode stacking block 44 can be suppressed and the discharge performance of the liquid discharge head can be stabilized.

[0059] Furthermore, in the first embodiment of the present invention, by using an internal electrode 51 that has been formed in advance to a predetermined width size, it is not necessary to provide dividing grooves 43 that divide the internal electrode 51 into predetermined widths, as shown in Figure 14. This also avoids variations in the processing of the internal electrode 51 caused by providing dividing grooves 43. As a result, the impact of variations in processing on discharge performance can also be reduced.

[0060] As described above, according to the present invention, it is possible to reduce the effects of both variations in processing caused by the large division of the piezoelectric member 40 by the dividing groove 43 and variations caused by misalignment of the internal electrodes 51, thereby suppressing variations in discharge performance and obtaining stable discharge performance.

[0061] In the first embodiment of the present invention, a dividing groove 43 is provided to divide the individual electrodes 52 (see Figure 7). However, the dividing groove 43 is not limited to being provided only on the individual electrode 52 side of the piezoelectric member 40, but may be provided continuously from the end face on the individual electrode 52 side to the end face on the common electrode 53 side of the piezoelectric member 40. Even in such a case, in the present invention, as shown in Figure 8, a stepped portion 45 is provided at the location where the dividing groove 43 is provided, which reduces the height (depth) of the dividing groove 43 compared to the case where there is no stepped portion 45. As a result, the cutting depth when forming the dividing groove 43 can be reduced, and variations in processing caused by cutting the dividing groove 43 too deeply can be suppressed.

[0062] On the other hand, it is preferable that the stepped portion 45 is provided continuously over the entire range in which the internal electrodes 51 are arranged, that is, from the end face of the piezoelectric member 40 on the individual electrode 52 side to the end face on the common electrode 53 side. However, if the desired discharge performance can be obtained, the stepped portion 45 is not necessarily provided over the entire range in which the internal electrodes 51 are arranged, but may be provided in only a part of the range in which the internal electrodes 51 are arranged. Also, the number of stepped portions 45 may be at least two or more.

[0063] The dividing grooves 43 and the stepped portions 45 can be processed by several processing methods, but from the viewpoint of processing cost and processability, processing by blade dicing is preferable. Specifically, in addition to blade dicing, other processing methods for the dividing grooves 43 include, for example, electrode patterning using a mask, but it is cheaper and easier to process by uniformly laminating the internal electrodes 51 and the piezoelectric layer 50 and then cutting them to a predetermined width by blade dicing. The stepped portions 45 can also be processed by dry etching, but the stepped portions 45 can also be processed cheaply and easily by using blade dicing.

[0064] However, when the stepped portion 45 is processed by blade dicing, variations in the stepped portion 45 due to processing tend to occur as the height dimension (depth) of the stepped portion 45 increases. Therefore, it is preferable that the height dimension of the stepped portion 45 be below a certain dimension. For this reason, in the present invention, as shown in Figure 8, the height dimension Ha of the stepped portion 45 is set to be less than or equal to the height dimension Hb from the joint surface 40a of the piezoelectric member 40 to the internal electrode 51 furthest from the joint surface 40a (the uppermost internal electrode 51 in the figure). As a result, the ratio of the height dimension to the width dimension of the stepped portion 45 (hereinafter referred to as the "aspect ratio") becomes smaller, and variations in processing caused by cutting the stepped portion 45 deeply by blade dicing can be suppressed.

[0065] Furthermore, in the first embodiment of the present invention, since the height dimension Ha of the stepped portion 45 is set to be less than or equal to the height dimension Hc from the joining surface 40a of the piezoelectric member 40 to the internal electrode 51 closest to the joining surface 40a (the lowest internal electrode 51 in Figure 8), the aspect ratio of the stepped portion 45 becomes even smaller, and the processing accuracy of the stepped portion 45 is improved. Also, as shown in Figure 8, if the width dimension Wa of the stepped portion 45 is made smaller than the width dimension Wb of the dividing groove 43, the aspect ratio of the stepped portion 45 becomes smaller, so that variations in the stepped portion 45 due to processing can be suppressed.

[0066] Furthermore, as shown in Figure 8, it is preferable that the widthwise dimension Wa of the stepped portion 45 is greater than or equal to the maximum widthwise displacement ΔL between the internal electrodes 51. By making the widthwise dimension Wa of the stepped portion 45 greater than or equal to the maximum widthwise displacement ΔL between the internal electrodes 51, the entire range, or almost all of the range, where displacement between the internal electrodes 51 occurs can be included within the widthwise region where the stepped portion 45 is located. This makes it possible to more reliably reduce the impact of the displacement of the internal electrodes 51 on the discharge performance, thereby making the discharge performance of the liquid discharge head more stable.

[0067] Here, when processing the stepped portion 45, it is generally expected that there will be a variation of 5% or less in the widthwise dimension Wa of the stepped portion 45 (variation in widthwise dimension). Therefore, if the maximum widthwise displacement ΔL between the internal electrodes 51 is 5% or more of the widthwise dimension of the maximum stacking range L, a particularly significant effect can be expected by providing a stepped portion 45 as in the present invention. That is, if the stepped portion 45 is not provided, the variation in the positional displacement of the internal electrodes 51 will be 5% or more, but by providing the stepped portion 45, the variation in the dimensions of the stepped portion 45 can be suppressed to 5% or less, thereby effectively reducing the impact on discharge performance due to the variation in the position of the internal electrodes 51.

[0068] Furthermore, the stepped portion 45 is preferably processed by blade dicing from the viewpoint of processing cost and machinability. In that case, the relationship between the height dimension Ha of the stepped portion 45, the thickness t of the blade used for blade dicing, and the height dimension Hb from the joining surface 40a of the piezoelectric member 40 to the internal electrode 51 furthest from the joining surface 40a is preferably satisfied by the following equations (1) and (2). That is, the height Ha of the stepped portion 45 is preferably greater than the thickness t of the blade (equation (1)), and the ratio of the height dimension Hb between the joining surface 40a and the internal electrode 51 furthest from the joining surface to the blade thickness t (Hb / t) is preferably less than 20 (equation (2)).

[0069] Ha>t...Equation (1) Hb / t<20...Equation (2)

[0070] In this way, the relationship between the height dimension Ha of the stepped portion 45, the thickness t of the blade, and the height dimension Hb from the joint surface 40a of the piezoelectric member 40 to the internal electrode 51 furthest from the joint surface 40a satisfies the above equations (1) and (2). As a result, the aspect ratio of the groove when processing the stepped portion 45 by blade dicing can be reduced, and variations in the stepped portion 45 due to processing can be suppressed more effectively.

[0071] Figure 10 is an enlarged cross-sectional view showing the electrode stacking block 44 according to the second embodiment of the present invention.

[0072] In the second embodiment of the present invention shown in Figure 10, the height dimension Ha of the stepped portion 45 is set to be greater than the height dimension Hc from the joining surface 40a of the piezoelectric member 40 to the internal electrode 51 closest to the joining surface 40a, which is different from the first embodiment of the present invention. Otherwise, the configuration is basically the same.

[0073] Thus, the height dimension Ha of the stepped portion 45 may be made larger than the height dimension Hc from the joint surface 40a of the piezoelectric member 40 to the internal electrode 51 closest to the joint surface 40a. However, even in this case, the height dimension Ha of the stepped portion 45 is set to be less than or equal to the height dimension Hb from the joint surface 40a of the piezoelectric member 40 to the internal electrode 51 furthest away. This reduces the aspect ratio of the stepped portion 45, thereby suppressing variations in processing due to blade dicing.

[0074] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the invention.

[0075] In the above embodiment, the liquid dispensing head according to the present invention was described as a so-called line-type liquid dispensing head that dispenses liquid while stationary relative to a conveyed sheet. However, the present invention is not limited to line-type liquid dispensing heads, but is also applicable to so-called serial-type liquid dispensing heads that dispense liquid while moving in a main scanning direction perpendicular to the sheet conveying direction. The configuration of a serial-type liquid dispensing head will be briefly described below.

[0076] <Configuration of a serial-type liquid dispensing head> Figure 11 is a plan view showing an example of a serial-type liquid dispensing head.

[0077] As shown in Figure 11, the serial-type liquid dispensing head 20 is mounted on a carriage 62 that is movable in the main scanning direction B (sheet width direction) perpendicular to the sheet transport direction A. The carriage 62 is configured to reciprocate in the main scanning direction B along a guide member 63.

[0078] Furthermore, the carriage 62 is driven by a drive unit 64. The drive unit 64 includes, for example, a motor 65 which is the drive source, and a timing belt 68 wrapped around a drive pulley 66 and a driven pulley 67. When the motor 65 is driven and the drive pulley 66 rotates, the timing belt 68 rotates, causing the carriage 62 to reciprocate along the guide member 63 in the main scanning direction B.

[0079] As shown in Figure 11, the sheet S is transported in the direction of arrow A, and when the sheet S reaches a predetermined image formation position, the transport of the sheet S is temporarily stopped. Then, as the carriage 62 moves in the main scanning direction B, liquid (ink) is ejected from the liquid ejection head 20. This forms an image of a predetermined width on the stationary sheet S. Subsequently, the intermittent transport (transport and stop) of the sheet S in the direction of arrow A and the liquid ejection operation accompanying the reciprocating movement of the carriage 62 in the main scanning direction B are repeated, thereby sequentially forming images on the sheet S.

[0080] By applying the present invention to the serial-type liquid discharge head 20 described above, the impact of variations in processing and variations in the positions of the internal electrodes on discharge performance can be reduced, and stable discharge performance can be obtained.

[0081] Furthermore, the liquid dispensing head according to the present invention may be mounted on other liquid dispensing devices in addition to the image forming apparatus described above. For example, the present invention is also applicable to a liquid dispensing head mounted on an electrode manufacturing apparatus that manufactures electrodes by dispensing a liquid composition. An example of an electrode manufacturing apparatus to which the present invention can be applied will be described below.

[0082] <Configuration of electrode manufacturing equipment> Figure 12 is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus 700 to which the present invention can be applied.

[0083] Here, as an example of an electrode manufacturing apparatus 700, a manufacturing apparatus for forming an electrode composite layer containing an active material on an electrode substrate (current collector) will be described. The electrode composite layer is used, for example, as part of the configuration of an electrochemical element. There are no particular restrictions on the components of the electrochemical element other than the electrode composite layer, and known components can be appropriately selected. For example, components other than the electrode composite layer include a positive electrode, a negative electrode, and a separator.

[0084] The electrode manufacturing apparatus 700 shown in Figure 12 includes an ejection process section 110 which includes a step of applying a liquid composition for manufacturing electrodes onto a printing substrate 704 having an object to be ejected to form a liquid composition layer, and a heating process section 130 which includes a heating step of heating the liquid composition layer to obtain an electrode composite layer.

[0085] Furthermore, the electrode manufacturing apparatus 700 includes a transport unit 705 for transporting the printing substrate 704. The transport unit 705 transports the printing substrate 704 at a preset speed in the order of the discharge process unit 110 and the heating process unit 130. There are no particular restrictions on the method for manufacturing the printing substrate 704 having an object to be discharged, such as an active material layer, and known methods can be appropriately selected. The discharge process unit 110 includes a liquid discharge head 281a that realizes a dispensing process for applying a liquid composition onto the printing substrate 704, a container 281b that contains the liquid composition 707, and a supply tube 281c that supplies the liquid composition 707 contained in the container 281b to the liquid discharge head 281a.

[0086] In the discharge process section 110, the liquid composition 707 is discharged from the liquid discharge head 281a and applied to the printing substrate 704, forming a thin film layer of the liquid composition. The containment container 281b may be integrated with the electrode manufacturing apparatus or may be detachable from the electrode manufacturing apparatus. Alternatively, the containment container 281b may be a container used for adding to a containment container integrated with the electrode manufacturing apparatus or a containment container detachable from the electrode manufacturing apparatus.

[0087] The containment container 281b and the supply tube 281c can be arbitrarily selected as long as they are capable of stably containing and supplying the liquid composition 707.

[0088] In the heating section 130, a solvent removal step is performed in which the solvent remaining in the liquid composition layer is heated and removed. Specifically, the solvent remaining in the liquid composition layer is heated and dried by the heating device 703 of the heating section 130, thereby removing the solvent from the liquid composition layer. This forms the electrode composite layer. Furthermore, the solvent removal step in the heating section 130 may be performed under reduced pressure.

[0089] There are no particular restrictions on the heating device 703, and it can be appropriately selected according to the purpose. For example, the heating device 703 can be a substrate heater, an IR heater, or a hot air heater. Alternatively, the heating device 703 may be a combination of at least two of the substrate heater, IR heater, and hot air heater. Furthermore, the heating temperature and heating time can be appropriately selected according to the boiling point of the solvent contained in the liquid composition 707 or the film thickness to be formed.

[0090] The object onto which the liquid composition is discharged (hereinafter sometimes referred to as the "discharge target") is not particularly limited as long as it is an object on which a layer containing electrode material is formed, and can be appropriately selected according to the purpose. For example, the target object may be an electrode substrate (current collector), an active material layer, or a layer containing solid electrode material. The target object may also be an electrode composite layer containing active material on an electrode substrate (current collector). Furthermore, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by directly discharging the liquid composition, as long as it is possible to form a layer containing electrode material on the discharge target. Alternatively, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by indirectly discharging the liquid composition.

[0091] By applying the present invention to the liquid discharge head 281a mounted on the electrode manufacturing apparatus 700 described above, the impact of processing variations and positional variations between internal electrodes on discharge performance can be reduced, resulting in stable discharge performance.

[0092] Furthermore, the present invention is broadly applicable not only to liquid dispensing devices that dispense liquid onto objects such as sheets or electrode substrates, but also to liquid dispensing devices that dispense liquid onto objects (targets) to which liquid can at least temporarily adhere. Examples of objects to which liquid is dispensed include paper, resin films, wallpaper, and electronic circuit boards. Examples of materials for objects to which liquid is dispensed include paper, leather, metal, plastic, glass, wood, and ceramics.

[0093] Furthermore, the liquid discharged by the liquid dispensing device according to the present invention is not particularly limited, but may include solutions, suspensions, emulsions, etc., containing water, solvents such as organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium, and edible materials such as natural pigments. These are used, for example, in inkjet inks, surface treatment liquids, components of electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D molding.

[0094] To summarize the embodiments of the present invention described above, the present invention includes at least the following embodiments.

[0095] [First aspect] A first embodiment is a liquid discharge head comprising: a plurality of nozzles for discharging liquid; a liquid chamber member having a plurality of individual liquid chambers individually communicating with the plurality of nozzles; and a piezoelectric actuator having a piezoelectric member for pressurizing the liquid in the individual liquid chambers via a diaphragm member constituting a part of the individual liquid chambers, wherein the piezoelectric member has a plurality of internal electrodes stacked for each of the plurality of individual liquid chambers, and a plurality of piezoelectric layers stacked across the plurality of individual liquid chambers so as to sandwich the internal electrodes, and the piezoelectric actuator has individual electrodes connected to the internal electrodes for each of the plurality of electrode stacking blocks consisting of the plurality of internal electrodes stacked for each of the plurality of individual liquid chambers, and the plurality of electrode stacking blocks A liquid discharge head having a common electrode connected to the internal electrode in common across the entire length, wherein the individual electrodes are separated by dividing grooves for each of the plurality of electrode stacking blocks, and the bonding surface of the piezoelectric member with the diaphragm member has at least two stepped portions, and when the stacking direction of the plurality of internal electrodes is defined as the height direction and the direction in which the plurality of electrode stacking blocks are aligned is defined as the width direction, the adjacent ends of the two stepped portions are located within the width direction range of the portion in which all of the internal electrodes of the electrode stacking block overlap in the height direction, and the height dimension of the two stepped portions is less than or equal to the height dimension from the bonding surface to the internal electrode furthest from the bonding surface.

[0096] [Second aspect] In the second embodiment, the height dimension of the two stepped portions is less than or equal to the height dimension from the joining surface to the internal electrode closest to the joining surface.

[0097] [Third aspect] In a third embodiment, in the first or second embodiment, at least one of the internal electrodes constituting the electrode stacking block is positioned offset in the width direction from the other internal electrodes.

[0098] [Fourth aspect] A fourth aspect is that, in the third aspect, the widthwise dimension of the two stepped portions is greater than or equal to the maximum widthwise displacement between the internal electrodes.

[0099] [Fifth aspect] A fifth aspect is that, in the third or fourth aspect, the maximum amount of misalignment in the width direction between the internal electrodes is 5% or more of the width dimension in the portion where all the internal electrodes of the electrode stacking block overlap in the height direction.

[0100] [Sixth aspect] The sixth aspect is a method for manufacturing a liquid dispensing head, wherein the stepped portion of the liquid dispensing head according to any one of the first to fifth aspects is processed by blade dicing.

[0101] [Seventh aspect] The seventh aspect is an aspect of the sixth aspect in which the height dimension of the stepped portion is greater than the thickness of the blade used for blade dicing, and the ratio of the height dimension between the joining surface and the internal electrode furthest from the joining surface to the thickness of the blade is less than 20.

[0102] [Eighth aspect] The eighth aspect is a method for manufacturing a liquid dispensing head, wherein the dividing groove of the liquid dispensing head according to any one of the first to fifth aspects is processed by blade dicing.

[0103] [Ninth aspect] The ninth embodiment is a liquid dispensing device that dispenses liquid onto an object using a liquid dispensing head according to any one of the first to fifth embodiments. [Explanation of symbols]

[0104] 20 liquid dispensing heads 22 Liquid chamber component 23. Diaphragm component 26 Piezoelectric Actuator 30 nozzles 31 Individual liquid chambers 40 Piezoelectric component 40a Joint surface 43 Dividing grooves 44 Electrode Stack Block 45 Stepped section 45a end 45b end 50 piezoelectric layers 51 Internal electrode 52 individual electrodes 53 Common electrode 100 Image forming device (liquid ejection device) ha Dimensions in the height direction of the stepped section Hb dimension in the height direction from the bonding surface to the internal electrode furthest from the bonding surface. Hc: Height dimension from the bonding surface to the internal electrode closest to the bonding surface. L: The widthwise range of the portion where all internal electrodes overlap in the height direction. t Blade thickness Wa: Dimensions in the width direction of the stepped section ΔL is the maximum displacement in the width direction between internal electrodes. [Prior art documents] [Patent Documents]

[0105] [Patent Document 1] Japanese Patent Application Publication No. 11-179898

Claims

1. Multiple nozzles for dispensing liquid, A liquid chamber member having a plurality of individual liquid chambers that communicate individually with the plurality of nozzles, A piezoelectric actuator having a piezoelectric member that pressurizes the liquid in the individual liquid chamber via a diaphragm member that constitutes a part of the individual liquid chamber, In a liquid dispensing head equipped with, The piezoelectric member has a plurality of internal electrodes stacked for each of the plurality of individual liquid chambers, and a plurality of piezoelectric layers stacked across the plurality of individual liquid chambers so as to sandwich the internal electrodes. The piezoelectric actuator has individual electrodes connected to the internal electrodes for each of the multiple electrode stacking blocks, each of which consists of multiple internal electrodes stacked for each of the multiple individual liquid chambers, and a common electrode connected to the internal electrodes in common across the multiple electrode stacking blocks. The individual electrodes are separated by dividing grooves for each of the plurality of electrode stacking blocks. The piezoelectric member has at least two stepped portions at the joint surface with the diaphragm member, If the stacking direction of the plurality of internal electrodes is defined as the height direction, and the direction in which the plurality of electrode stacking blocks are arranged is defined as the width direction, The adjacent ends of the two stepped portions are located within the widthwise range of the portion where all of the internal electrodes of the electrode stacking block overlap in the height direction. A liquid dispensing head characterized in that the height dimension of the two stepped portions is less than or equal to the height dimension from the joint surface to the internal electrode furthest from the joint surface.

2. The liquid dispensing head according to claim 1, wherein the height dimension of the two stepped portions is less than or equal to the height dimension from the joint surface to the internal electrode closest to the joint surface.

3. The liquid dispensing head according to claim 1, wherein at least one of the internal electrodes constituting the electrode stacking block is arranged offset in the width direction relative to the other internal electrodes.

4. The liquid discharge head according to claim 3, wherein the widthwise dimension of the two stepped portions is greater than or equal to the maximum amount of displacement in the widthwise direction between the internal electrodes.

5. The liquid dispensing head according to claim 3 or 4, wherein the maximum amount of misalignment in the width direction between the internal electrodes is 5% or more of the width dimension in the portion where all the internal electrodes of the electrode stacking block overlap in the height direction.

6. A method for manufacturing a liquid dispensing head, characterized in that the stepped portion of the liquid dispensing head described in claim 1 is processed by blade dicing.

7. The height dimension of the stepped portion is greater than the thickness of the blade used for blade dicing. The method for manufacturing a liquid discharge head according to claim 6, wherein the ratio of the height dimension between the joint surface and the internal electrode furthest from the joint surface to the thickness of the blade is less than 20.

8. A method for manufacturing a liquid dispensing head, characterized in that the dividing groove of the liquid dispensing head described in claim 1 is processed by blade dicing.

9. A liquid dispensing device characterized by dispensing liquid onto an object using the liquid dispensing head described in claim 1.

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