JP2018051934A - Liquid jet head and liquid jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head of high reliability.SOLUTION: A liquid jet head includes: a pressure chamber formation member in which a pressure generation chamber is formed, that communicates with a nozzle for discharging droplets and that is partitioned by partition walls; and a piezoelectric element disposed on one surface of the pressure chamber formation member and obtained by laminating a first electrode layer, a piezoelectric layer, and a second electrode layer. The first electrode layer is formed at a position corresponding to the pressure generation chamber, whereas the piezoelectric layer is formed at a position corresponding to the pressure generation chamber, so as to cover an upper face and an end face of the first electrode layer. The second electrode layer covers the piezoelectric layer and is formed at a position corresponding to the pressure generation chamber and an upper part of the partition walls. Further, in the liquid jet head, a resin layer is formed on the second electrode layer formed on the upper part of the partition walls.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus.

  Conventionally, for example, as described in Patent Document 1, a pressure chamber forming member that is in communication with a nozzle that discharges droplets and that is partitioned by a partition wall is formed, and one of the pressure chamber forming members. There has been known a liquid ejecting head that includes a piezoelectric element that is provided on a surface and is laminated with a first electrode layer, a piezoelectric layer, and a second electrode layer.

JP 2009-172878 A

  However, the liquid ejecting head described in Patent Document 1 has a problem that cracks are generated from the end of the partition wall because stress tends to concentrate on the end of the partition wall when the piezoelectric element is bent.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid jet head according to this application example includes a pressure chamber forming member in which a pressure generating chamber is formed which communicates with a nozzle for discharging droplets and is partitioned by a partition, and one of the pressure chamber forming members And a piezoelectric element laminated on the first electrode layer, the piezoelectric layer, and the second electrode layer, wherein the first electrode layer is formed at a position corresponding to the pressure generating chamber. The piezoelectric layer is a position corresponding to the pressure generating chamber and is formed so as to cover an upper surface and an end surface of the first electrode layer, and the second electrode layer covers the piezoelectric layer, A liquid ejecting head formed at a position corresponding to the pressure generating chamber and the upper part of the partition wall, wherein a resin layer is formed on the second electrode layer formed on the upper part of the partition wall. Features.

  According to this application example, by providing the resin layer on the upper part of the partition wall, the stress concentration of the partition wall with respect to the deflection of the piezoelectric element is relieved, and damage to the liquid ejecting head can be prevented.

  Application Example 2 In the liquid ejecting head according to the application example, the resin layer is formed on the second electrode layer formed on the partition and at a position corresponding to the pressure generation chamber. It is preferably formed on the second electrode layer.

  According to this application example, by providing a resin layer on the upper part of the pressure generation chamber in addition to the upper part of the partition wall, the stress concentration of the partition wall against the deflection of the piezoelectric element is further reduced, and damage to the liquid ejecting head is prevented. Can do.

  Application Example 3 In the liquid jet head according to the application example described above, it is preferable that the resin layer is formed to have a thickness equal to or greater than the thickness of the piezoelectric element.

  According to this application example, by forming the resin layer thick, the stress concentration of the partition wall with respect to the deflection of the piezoelectric element is further reduced, and damage to the liquid ejecting head can be prevented.

  Application Example 4 In the liquid jet head according to the application example described above, it is preferable that the resin layer is a photosensitive resin material.

  According to this application example, the resin layer can be easily formed by using the photosensitive resin material.

  Application Example 5 The liquid jet head according to the application example includes a protective substrate that covers an upper portion of the piezoelectric element, and the protective substrate is in contact with the resin layer formed on the upper portion of the partition wall. Is preferred.

  According to this application example, since the resin layer on the upper side of the partition wall and the protective substrate are in contact with each other, the resin layer is stably pressed against the partition wall, so that the stress concentration on the partition wall is alleviated and the liquid jet head is damaged. Can be prevented.

  Application Example 6 A liquid ejecting apparatus according to this application example includes the liquid ejecting head described above.

  According to this application example, it is possible to provide a highly reliable liquid ejecting apparatus in which damage to the liquid ejecting head is reduced.

FIG. 3 is an exploded perspective view of the liquid ejecting head according to the first embodiment. FIG. 3 is a plan view of the liquid ejecting head according to the first embodiment. FIG. 3 is a cross-sectional view of the liquid ejecting head according to the first embodiment. FIG. 3 is a partial cross-sectional view illustrating the liquid ejecting head according to the first embodiment. FIG. 6 is a partial cross-sectional view illustrating a liquid jet head according to a second embodiment. FIG. 6 is a cross-sectional view of a liquid jet head according to a third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of a liquid jet head 1 according to Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is AA ′ of FIG. FIG. 4 is a partial cross-sectional view taken along the line BB ′ of FIG.

  As shown in the figure, in the liquid ejecting head 1, the pressure chamber forming member 10 is made of a silicon single crystal substrate having a crystal plane orientation of (110) in this embodiment, and an elastic film 50 made of an oxide film on one surface thereof. Is formed. In the pressure chamber forming member 10, a plurality of pressure generating chambers 12 which are partitioned by a partition wall 11 and whose one surface is constituted by an elastic film 50 are arranged in parallel in the width direction.

  In the pressure chamber forming member 10, an ink supply path 13 and a communication path 14 are provided on one end side in the longitudinal direction of the pressure generating chamber 12 and communicate with each pressure generating chamber 12 partitioned by the partition wall 11. A communication portion 15 that communicates with each communication path 14 is provided outside the communication path 14. The communication portion 15 communicates with the reservoir portion 32 of the protective substrate 30 and constitutes a part of the reservoir 100 that becomes a common ink chamber (liquid chamber) of each pressure generating chamber 12. The longitudinal direction of the pressure generating chamber 12 is a direction parallel to the AA ′ cross-sectional view in FIG. 2 of the plan view, and the short direction and the width direction of the pressure generating chamber 12 are BB in FIG. 'The direction is parallel to the cross-sectional view. Further, the thickness direction is the thickness direction of the pressure chamber forming substrate, the protective substrate 30 and the like, and is a direction perpendicular to the paper surface in FIG. 2 of the plan view.

  Here, the ink supply path 13 is formed to have a narrower cross-sectional area than the pressure generation chamber 12, and the flow path resistance of the ink flowing into the pressure generation chamber 12 from the communication portion 15 is kept constant. . For example, the ink supply path 13 is formed with a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. . In this embodiment, the ink supply path is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Each communication passage 14 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 toward the communication portion 15 to partition the space between the ink supply path 13 and the communication portion 15. Yes.

  As a material for the pressure chamber forming member 10, a silicon single crystal substrate is used in the present embodiment, but it is needless to say that the material is not limited thereto. For example, glass ceramics, stainless steel, or the like may be used.

  On the opening surface side of the pressure chamber forming member 10, a nozzle plate 20 having a nozzle 21 communicating with the vicinity of the end portion of each pressure generating chamber 12 on the side opposite to the ink supply path 13 is provided with an adhesive or heat welding. It is fixed by a film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 is formed on the opposite side of the pressure chamber forming member 10 as described above, and an oxide film made of a material different from the elastic film 50 is formed on the elastic film 50. An insulating film 55 is formed. Furthermore, a piezoelectric element 300 including a first electrode layer 60, a piezoelectric layer 70, and a second electrode layer 80 is formed on the insulator film 55. Here, the piezoelectric element 300 includes at least a portion having the piezoelectric layer 70 as well as a portion having the first electrode layer 60, the piezoelectric layer 70 and the second electrode layer 80. In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode is patterned together with the piezoelectric layer 70 for each pressure generating chamber 12 to form individual electrodes. Also, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the example described above, the elastic film 50, the insulator film 55, and the first electrode layer 60 function as a diaphragm, but the elastic film 50 and the insulator film 55 are not provided, and only the first electrode layer 60 is left. The first electrode layer 60 may be a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  Here, the structure of the piezoelectric element 300 according to the present embodiment will be described in detail. As shown in FIG. 4, the first electrode layer 60 constituting the piezoelectric element 300 is provided with a width narrower than the width of the pressure generation chamber 12 for each region facing each pressure generation chamber 12. The individual electrodes are configured. The first electrode layer 60 is extended from one end side in the longitudinal direction of each pressure generating chamber 12 to the peripheral wall. The first electrode layer 60 is connected to a lead electrode 90 made of, for example, gold (Au) or the like in a region outside the pressure generation chamber 12, and is selectively connected to each piezoelectric element 300 via the lead electrode 90. A voltage is applied to. On the other hand, the end of the first electrode layer 60 on the other end side in the longitudinal direction of the pressure generation chamber 12 is located in a region facing the pressure generation chamber 12.

  The piezoelectric layer 70 is provided with a width wider than the width of the first electrode layer 60 and narrower than the width of the pressure generation chamber 12. In the longitudinal direction of the pressure generation chamber 12, both end portions of the piezoelectric layer 70 are extended to the outside of the end portion of the pressure generation chamber 12. That is, the piezoelectric layer 70 is provided so as to completely cover the upper surface and the end surface of the first electrode layer 60 in a region facing the pressure generation chamber 12. Note that the end of the piezoelectric layer 70 on one end side in the longitudinal direction of the pressure generating chamber 12 is located in the vicinity of the end of the pressure generating chamber 12, and the first electrode layer 60 further extends in the outer region. Has been.

  The second electrode layer 80 is continuously formed in a region facing the plurality of pressure generating chambers 12, and extends from the other end in the longitudinal direction of the pressure generating chamber 12 to the peripheral wall. That is, the second electrode layer 80 is provided so as to cover almost the entire upper surface and end surface of the piezoelectric layer 70 in a region facing the pressure generation chamber 12.

  On the pressure chamber forming member 10 on which such a piezoelectric element 300 is formed, a protective substrate 30 having a piezoelectric element holding portion 31 capable of ensuring a space that does not hinder its movement in a region facing the piezoelectric element 300 is provided. They are joined via an adhesive 35. Since the piezoelectric element 300 is formed in the piezoelectric element holding part 31, it is protected in a state hardly affected by the external environment. The protective substrate 30 is provided with a reservoir portion 32 in a region corresponding to the communication portion 15 of the pressure chamber forming member 10. In the present embodiment, the reservoir portion 32 is provided along the direction in which the pressure generation chambers 12 pass through the protective substrate 30 in the thickness direction. As described above, the communication portion of the pressure chamber forming member 10 is provided. 15, a reservoir 100 is formed which serves as a common ink chamber for the pressure generation chambers 12.

  Further, a through hole 33 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 31 and the reservoir portion 32 of the protective substrate 30, and leads connected to the first electrode layer 60. An end portion of the electrode 90 is exposed in the through hole 33. Although not shown, the lead electrode 90 is connected to a drive IC or the like for driving the piezoelectric element 300 by connection wiring extending in the through hole 33.

  In addition, examples of the material of the protective substrate 30 include glass, ceramic material, metal, resin, and the like, but it is more preferable that the protective substrate 30 is formed of substantially the same material as the thermal expansion coefficient of the pressure chamber forming member 10. In this embodiment, the pressure chamber forming member 10 is formed using a silicon single crystal substrate made of the same material.

  On the protective substrate 30, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is further bonded. The sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the reservoir portion 32 is sealed by the sealing film 41. The fixed plate 42 is formed of a hard material such as metal. Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In the liquid ejecting head 1 according to this embodiment, after taking ink from an external ink supply unit (not shown) and filling the interior from the reservoir 100 to the nozzle 21 with the ink, according to a recording signal from a driving IC (not shown), By applying a voltage to each piezoelectric element 300 corresponding to the pressure generation chamber 12 to bend and deform the piezoelectric element 300, the pressure in each pressure generation chamber 12 increases, and ink droplets as droplets are ejected from the nozzles 21. .

  Here, in the liquid jet head 1 according to the present embodiment, the resin layer is formed on the second electrode layer 80 formed on the upper part of the partition wall 11 (on the side opposite to the side where the insulator film is located in the second electrode). 110 is formed. Specifically, as shown in FIGS. 1 and 4, the resin layer 110 has a substantially rectangular parallelepiped shape, and extends in the longitudinal direction of the partition wall 11 (longitudinal direction of the pressure generating chamber 12). The widths of both end portions of the resin layer 110 in the short direction (short direction of the pressure generating chamber 12 and width direction of the pressure generating chamber 12) are equal to or wider than the width of the partition wall 11. As shown in FIGS. 1 and 2, the length of the resin layer 110 in the longitudinal direction is equal to or longer than the length of the piezoelectric element 300 formed corresponding to each pressure generating chamber 12 in the longitudinal direction. In addition, the resin layer 110 and the piezoelectric element 300 formed corresponding to each pressure generating chamber 12 are formed in parallel.

  In addition, the thickness of the resin layer 110 of the present embodiment is desirably equal to or greater than the thickness of the piezoelectric element 300. For example, it is desirable to form the piezoelectric element 300 with a thickness that is 1 to 2 times the thickness of the piezoelectric element 300.

  Moreover, as a material of the resin layer 110 of this embodiment, for example, a photosensitive resin material is used. Thereby, it can be formed by photolithography, and the resin layer 110 can be easily formed with high accuracy. The material of the resin layer 110 is not limited to the photosensitive resin material, and for example, a thermosetting resin material or the like may be used.

  As described above, according to the liquid jet head 1 according to the present embodiment, when the piezoelectric element 300 is driven, the diaphragm including the elastic film 50 bends, and the partition 11 and the elastic film 50 are connected to each other (the partition wall). However, the stress of the partition wall 11 due to the deflection of the diaphragm including the elastic film 50 can be obtained by providing the resin layer 110 on the top of the partition wall 11. The concentration is relaxed, and the effect of preventing damage to the liquid jet head 1 can be obtained.

(Embodiment 2)
FIG. 5 is a cross-sectional view of the liquid jet head 1a according to the second embodiment.
In addition, about the component same as Embodiment 1, the same number is used and the overlapping description is abbreviate | omitted.

  In the liquid ejecting head 1a according to the present embodiment, the resin layer is formed on the second electrode layer 80 formed on the partition 11 and on the second electrode layer 80 formed at a position corresponding to the pressure generation chamber 12. 110a is formed. Specifically, as shown in FIG. 5, the entire region on the second electrode layer formed above the partition wall 11 and the entire region on the second electrode layer formed above the pressure generating chamber 12 are made of resin. The layer 110a is formed.

  Further, as shown in FIG. 5, the resin layer 110a of the present embodiment is formed so that the surface is flat. That is, the thickness of the resin layer 110a is different between the upper part of the partition wall 11 and the upper part of the piezoelectric element 300. Note that the resin layer 110 a may not be formed flat as shown in FIG. 5 but may be formed unevenly along the shape of the piezoelectric element 300. That is, the thickness of the resin layer 110a may be uniform.

  Note that the region corresponding to the pressure generation chamber 12 in which the resin layer 110a of the present embodiment is formed is not formed in the entire region on the second electrode layer 80 formed in the upper portion of the pressure generation chamber 12, and pressure generation is performed. The resin layer 110a may be formed in a region corresponding to at least a portion including both ends of the piezoelectric layer 70 on the second electrode layer 80 formed in the upper portion of the chamber 12.

  As described above, according to the liquid jet head 1a, in addition to the effects of the first embodiment, the resin layer is formed on the second electrode layer 80 formed on the upper portion of the pressure generating chamber 12 in addition to the upper portion of the partition wall 11. By being formed in 110a, the stress concentration of the partition wall 11 with respect to the deflection of the piezoelectric element 300 (vibrating plate) is further relaxed, and the effect of preventing damage to the liquid jet head 1a can be obtained.

(Embodiment 3)
FIG. 6 is a cross-sectional view of the liquid jet head 1b according to the third embodiment.
In addition, about the component same as Embodiment 1, the same number is used and the overlapping description is abbreviate | omitted.

  The liquid ejecting head 1b according to the present embodiment includes the protective substrate 30 that covers the upper portion of the piezoelectric element 300, and the protective substrate 30 and the resin layer 110b are in contact with each other. Specifically, as shown in FIG. 6, in the state where the resin layer 110 b formed on the second electrode layer 80 and the inner surface 30 a of the protective substrate 30 is in contact with the upper surface of the partition wall 11. A protective substrate 30 is disposed on 300. The resin layer 110b and the inner side surface 30a of the protective substrate 30 may be bonded with an adhesive or the like.

  Further, the resin layer 110b of the present embodiment is not formed by only one layer, but the resin layer 110b may be configured by two or more layers.

  As described above, according to the liquid ejecting head 1b, in addition to the effects of the first embodiment, the resin layer 110b formed on the second electrode layer 80 above the partition wall 11 is in contact with the protective substrate 30. Furthermore, the stress concentration of the partition wall 11 with respect to the deflection of the piezoelectric element 300 (vibrating plate) is alleviated, and the effect of preventing damage to the liquid ejecting head 1b can be obtained.

  The liquid ejecting heads 1, 1 a, and 1 b described above constitute a part of an ink jet recording head unit that includes an ink flow path that works with a cartridge or the like, and are mounted on an ink jet recording apparatus (liquid ejecting apparatus). . A carriage on which the head unit is mounted is provided on a carriage shaft attached to the apparatus main body so as to be movable in the axial direction. For example, the head unit discharges a black ink composition and a color ink composition, respectively. The driving force of the driving motor is transmitted to the carriage via a plurality of gears and a timing belt, so that the carriage on which the head unit is mounted is moved along the carriage shaft. On the other hand, the apparatus body is provided with a platen along the carriage shaft, and a recording sheet, which is a recording medium such as paper fed by a paper feed roller, is wound around the platen and conveyed. Yes. Note that the head is mounted on the carriage and moves in the main scanning direction as an example. However, the present invention is not limited to this. For example, an ink jet recording head is fixed and a recording sheet such as paper is moved in the sub scanning direction. The present invention can also be applied to a so-called line type recording apparatus that performs printing only by moving it to the position.

  In the above embodiment, an ink jet recording head has been described as an example of a liquid ejecting head, and an ink jet recording apparatus has been described as an example of a liquid ejecting apparatus. The present invention is intended for the entire apparatus, and can of course be applied to a liquid ejecting head and a liquid ejecting apparatus that eject liquid other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bio-organic matter ejection head used for biochip production, and the like, and can also be applied to a liquid ejection apparatus provided with such a liquid ejection head.

  DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Liquid jet head, 10 ... Pressure chamber formation member, 11 ... Partition, 12 ... Pressure generating chamber, 20 ... Nozzle plate, 21 ... Nozzle, 30 ... Protection substrate, 30a ... Inner side surface, 40 ... Compliance substrate , 50 ... elastic film, 55 ... insulator film, 60 ... first electrode layer, 70 ... piezoelectric layer, 80 ... second electrode layer, 100 ... reservoir, 110, 110a, 110b ... resin layer, 300 ... piezoelectric element.

Claims (6)

A pressure chamber forming member that communicates with a nozzle that discharges the liquid droplets and that has a pressure generating chamber partitioned by a partition; and is provided on one surface of the pressure chamber forming member; a first electrode layer; a piezoelectric layer; And a piezoelectric element laminated with a second electrode layer,
The first electrode layer is formed at a position corresponding to the pressure generation chamber,
The piezoelectric layer is a position corresponding to the pressure generation chamber, and is formed so as to cover the upper surface and the end surface of the first electrode layer,
The second electrode layer is a liquid jet head that covers the piezoelectric layer and is formed at a position corresponding to the upper part of the pressure generation chamber and the partition wall,
A liquid jet head, wherein a resin layer is formed on the second electrode layer formed on the partition. The liquid ejecting head according to claim 1,
The resin layer is formed on the second electrode layer formed above the partition and on the second electrode layer formed at a position corresponding to the pressure generating chamber. Jet head. The liquid ejecting head according to claim 1, wherein
The liquid ejecting head according to claim 1, wherein the resin layer has a thickness equal to or greater than a thickness of the piezoelectric element. The liquid ejecting head according to any one of claims 1 to 3,
The liquid ejecting head, wherein the resin layer is a photosensitive resin material. In the liquid ejecting head according to any one of claims 1 to 4,
A liquid ejecting head, comprising: a protective substrate covering an upper portion of the piezoelectric element, wherein the protective substrate is in contact with the resin layer formed on the upper portion of the partition wall.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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