JP2011156682A - Liquid droplet jetting head and method for manufacturing liquid droplet jetting head - Google Patents

Abstract

A droplet capable of suppressing a possibility that a piezoelectric element is short-circuited by electroosmosis of a droplet of ink or the like and efficiently transmitting a displacement generated by driving the piezoelectric element to a pressure generating chamber. Provided is a liquid droplet ejecting head including a permeation protection unit.
Between an actuator 30 and a cavity unit 10 having a pressure chamber 19, four layers of stress relaxation layers 21a to 21d and three layers of stop members 22 to 24 are alternately arranged, and a plurality of layers are provided. The area corresponding to the open surface of the pressure chamber 19 is covered by the first layer stop member 22, and the area not covered by the first layer stop member 22 is covered by the second layer stop member 23 and the third layer stop member 24. Is called.
[Selection] Figure 3

Description

  The present invention relates to a droplet ejecting head in which a piezoelectric element is driven to eject droplets, and a method for manufacturing the droplet ejecting head.

  Conventionally, there is a liquid ejection device including a cavity unit and an actuator unit. The cavity unit includes a nozzle that ejects liquid and a pressure chamber that communicates with the ink chamber. In the actuator unit, ceramic layers and common electrodes or individual electrodes are alternately stacked to generate a discharge pressure in the pressure chamber of the cavity unit. The ceramic layer of the actuator unit is bonded to the cavity unit to form the liquid ejection device. However, the actuator unit tends to crack in the ceramic layer during firing or driving, and when ink enters the crack through the pressure chamber, it penetrates into the ceramic layer and electrically shorts the common electrode and individual electrodes. There is a fear. For this reason, in the actuator unit of the liquid ejection device described in Patent Document 1, a barrier layer that does not allow liquid to pass between the ceramic layer and the common electrode is commonly provided in a plurality of pressure chambers, and these are sintered. The integrated configuration prevents the electrodes from being electrically short-circuited even if a crack occurs in the ceramic layer.

JP 2008-302612 A

  However, even in the case of an actuator unit in which the barrier layer and the ceramic layer are integrated by sintering, the surface bonded to the cavity unit or the surface opposite to the surface bonded to the cavity unit in the process of bonding to the cavity unit, etc. When a force is applied to the barrier layer, the barrier layer may crack together with the integrated ceramic layer. When a liquid ejection device in which a crack is generated in the ceramic layer and the barrier layer is used, the liquid may permeate the actuator unit through the crack and cause an electrical short circuit. In addition, if the barrier layer is thickened to prevent the occurrence of cracks and is provided in common for multiple pressure chambers, the walls of each pressure chamber will be an impeding factor, and displacement due to driving of the actuator unit will be sufficiently transmitted to the pressure chamber. There is no problem.

  The present invention has been made to solve the above-described problems, and is a liquid that suppresses the possibility of an electrical short circuit of an actuator unit and efficiently transmits a displacement generated by driving the actuator unit to a pressure chamber. An object is to provide a droplet ejecting head.

  In order to achieve this object, a droplet ejecting head according to claim 1 includes a droplet ejecting unit having a pressure chamber connectable to a liquid supply source, a piezoelectric element unit that pressurizes the pressure chamber, and the piezoelectric element. And a liquid permeation protector disposed between the liquid droplet ejecting unit, and the liquid permeation protector prevents liquid from the pressure chamber from penetrating into the piezoelectric element unit. A stop layer composed of a plurality of layers, a region facing the piezoelectric element portion, a surface between the stop layer, and a region facing the pressure chamber, at least the surface on the piezoelectric element portion side of each stop layer And a stress relaxation layer sandwiching the pressure chamber side surface, the stop layer is composed of a plurality of subdivided stop members, and the stop member of the one stop layer is a plurality of stop members. By stop member Is disposed so as to cover the serial pressure chamber, to the surface of the pressure chamber facing said one stop layer, the stop members of the other of the stop layer is characterized in that it is arranged without a gap.

  The droplet ejection head according to claim 2, comprising: an individual electrode smaller than the pressure chamber disposed corresponding to the pressure chamber; and a common electrode facing the individual electrode, wherein the one stop layer At least one of the stop members is arranged in a region corresponding to the individual electrode and the pressure chamber.

  The droplet ejecting head according to claim 3, wherein each of the stop members of the stop layer closest to the pressure chamber does not cross at least two opposing sides of the wall defining the pressure chamber. It arrange | positions so that a part of may be covered.

  Further, in the liquid droplet ejecting head according to claim 4, each of the stop members of the stop layer closest to the individual electrode may be configured so that a part of the individual electrode is not traversed at least across two opposing sides of the individual electrode. A liquid droplet ejecting head, wherein the liquid droplet ejecting head is arranged so as to cover.

  Further, the liquid droplet ejecting head according to claim 5 is characterized in that the plurality of stop members arranged in the one stop layer are arranged at an interval narrower than the size of the stop member.

  The droplet ejecting head according to claim 6 has a three-layer structure in which the stop layer includes a plurality of stop members having the same shape on a plurality of straight lines extending in parallel to the surface direction of the layers. The stop member of the first stop layer is disposed so as to cover the pressure chamber, the stop member of the second stop layer is disposed so as to cover a connection portion between the stop members of the first stop layer, The stop member of the third stop layer is disposed so as to cover the connection portion between the stop members of the first stop layer and not covered by the stop member of the second stop layer. It is characterized by.

  Further, in the liquid droplet ejecting head according to claim 7, the stop layer is disposed such that a stop member disposed on a specific straight line is in contact with two stop members disposed on adjacent straight lines. It is characterized by.

  The droplet ejecting head according to claim 8 is characterized in that the stop member has a convex shape in the direction of the piezoelectric element portion or in the direction of the droplet ejecting portion.

  The method for manufacturing a liquid droplet ejecting head according to claim 9 is the method for manufacturing a liquid droplet ejecting head according to claim 1, wherein each of the stop layers composed of a plurality of layers of the liquid droplet permeation protection portion is the piezoelectric. They are stacked in order from the element unit side to the droplet ejecting unit side.

  The liquid droplet ejecting head according to claim 1, wherein the stop member of one stop layer is disposed so as to cover the pressure chamber, and the stop member of the other stop layer straddles between the stop members of the one stop layer. Therefore, the liquid permeation path from the pressure chamber to the piezoelectric element portion can be lengthened, and the possibility that the piezoelectric element portion is short-circuited due to electroosmosis can be reduced. Further, since the stress relaxation layer is provided between the stop layers, the stress concentrated on each stop layer is reduced, and the breakage of the stop member is suppressed. Further, since the stop member is subdivided, the displacement due to the piezoelectric element portion can be transmitted to the pressure chamber.

  In the liquid droplet ejecting head according to the second aspect, since the stop member is provided in a region sandwiched between the individual electrode and the pressure chamber, the shortest permeation path of the liquid between the individual electrode and the pressure chamber is blocked, Occurrence of short-circuiting of individual electrodes due to electroosmosis can be prevented.

  According to a third aspect of the present invention, each of the stop members of the stop layer closest to the pressure chamber allows at least a part of the pressure chamber to pass without traversing at least two opposing sides of the wall defining the pressure chamber. Since it arrange | positions so that it may cover, possibility that a stop member will crack is reduced, generation | occurrence | production of the short circuit of a piezoelectric element can be prevented, and the displacement by a piezoelectric element part can be transmitted to a pressure chamber.

  Further, in the liquid droplet ejecting head according to claim 4, each of the stop members of the stop layer closest to the individual electrode covers at least a part of the individual electrode without traversing two opposing sides of the individual electrode. Therefore, it is possible to reduce the possibility that the stop member breaks and to prevent an electrical short circuit between the individual electrodes.

  Further, in the liquid droplet ejecting head according to the fifth aspect, since the plurality of stop members of the stop layer are provided at intervals narrower than the width of the stop member, the stop member that fills the width between the stop members is provided more than necessary. In addition, the pressure chamber can be efficiently covered with a limited number of stop members and layers.

  Further, in the liquid droplet ejecting head according to claim 6, since the plurality of stop members having the same shape are arranged on a plurality of straight lines extending in parallel and the pressure chamber is covered by the three layers of stop members, the shape of the stop member In consideration of the shape of each stop member according to the arrangement, it is not necessary to arrange the pressure chamber with only the stop member of one stop layer, and the pressure chamber can be covered with a small number of layers. Moreover, since the number of layers is small, the displacement due to the piezoelectric element portion can be reliably transmitted to the pressure chamber.

  Further, in the liquid droplet ejecting head according to the seventh aspect, since the stop member arranged on the specific straight line is arranged so as to contact the two stop members arranged on the adjacent straight line, the stop member is made efficient. The pressure chamber can be covered with a small number of members and a minimum number of layers.

  Further, in the liquid droplet ejecting head according to the eighth aspect, since the stop member has a convex shape in the direction of the piezoelectric element portion or the direction of the liquid droplet ejecting portion, the piezoelectric element portion and the liquid are less than the case where the stop member is a flat surface. It has a height in the direction of the ejecting portion, can extend the liquid permeation path, and can reduce the possibility of a short circuit of the piezoelectric element portion.

  Further, in the method of manufacturing the droplet ejecting head according to claim 9, the stop member of one stop layer is disposed so as to cover the pressure chamber, and the stop member of the other stop layer is the stop member of the one stop layer. Since it is arranged so as to straddle between, the liquid penetration path from the pressure chamber to the piezoelectric element part can be lengthened, and the possibility that the piezoelectric element part is short-circuited by electroosmosis can be reduced. In addition, each stop layer consisting of multiple layers of the liquid permeation protection part is laminated in order from the piezoelectric element part side to the droplet ejecting part side, so a stop layer is provided corresponding to the piezoelectric element part and short-circuited by electroosmosis It is possible to reliably reduce the possibility of doing so. In addition, since the stress relaxation layer is provided between the stop layers, the stress concentrated on each stop layer can be reduced, and breakage of the stop member can be suppressed. Further, the subdivided stop member can reliably transmit the displacement due to the piezoelectric element portion to the pressure chamber.

1 is an exploded perspective view of a piezoelectric inkjet head 1 in Embodiment 1. FIG. 2 is a partial cross-sectional view of the piezoelectric inkjet head 1. FIG. 2 is a cross-sectional view of an ink permeation protective layer 20 of the piezoelectric inkjet head 1. FIG. FIG. 6 is a top view showing the arrangement of the first layer stop member 22 of the ink permeation protection layer 20 corresponding to the pressure chamber 19. FIG. 4 is a top view showing the arrangement of a first layer stop member 22 and a second layer stop member 23 of the ink permeation protection layer 20 corresponding to the pressure chamber 19. FIG. 6 is a top view showing the arrangement of a first layer stop member 22, a second layer stop member 23, and a third layer stop member 24 of the ink permeation protection layer 20 corresponding to the pressure chamber 19. 4 is a processing procedure flowchart showing a forming process of the ink permeation protection layer 20. FIG. 6 is a process change diagram showing a process of forming the ink permeation protection layer 20. It is a top view which shows arrangement | positioning of each said stop member 22-24. It is sectional drawing which shows arrangement | positioning of each said stop member 22-24. It is a top view which shows arrangement | positioning of each stop member 122-124 in this Embodiment 2. FIG. It is sectional drawing which shows arrangement | positioning of each said stop member 122-124. It is a top view which shows arrangement | positioning of each stop member 222-225 in this Embodiment 3. FIG. It is sectional drawing which shows arrangement | positioning of each said stop member 222-225.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

<Embodiment 1>
The overall configuration of the piezoelectric inkjet head 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is an exploded perspective view of the piezoelectric inkjet head 1. FIG. 2 is a partial cross-sectional view of the piezoelectric inkjet head 1 shown in FIG. The left-right direction, the up-down direction, and the front-rear direction in the first embodiment are defined as shown in FIG. 1, and the piezoelectric inkjet head 1 will be described. The piezoelectric inkjet head 1 includes a cavity unit 10, an ink permeation protection layer 20, an actuator 30, and a flexible wiring material 40. As shown in FIG. 1, in the piezoelectric inkjet head 1, the ink permeation protection layer 20 and the actuator 30 are stacked on the cavity unit 10 in the upward direction, and the flexible wiring member 40 is further attached to the actuator 30. Arranged in layers.

  As shown in FIG. 2, the cavity unit 10 has a configuration in which a nozzle plate 11, a spacer plate 12, a manifold 13, a supply plate 14, a base plate 15, and a cavity plate 16 are stacked in the upward direction. The nozzle plate 11 is provided with a nozzle port 17. An ink chamber 18 serving as an ink flow path is provided in a part of the manifold 13. Ink is supplied to the ink chamber 18 from a liquid supply source such as an ink cartridge (not shown). A pressure chamber 19 that communicates with the nozzle port 17 and the ink chamber 18 is provided in a part of the cavity plate 16. In the cavity unit 10, the pressure chamber 19 is positioned so as to be parallel to the individual electrode 31 (described later) in the vertical direction, and the upper surface of the cavity plate 16 is joined to the ink permeation protection layer 20.

  The actuator 30 has a structure in which nine piezoelectric sheet layers 35 made of a piezoelectric ceramic material such as lead zirconate titanate (PZT), the individual electrodes 31 and the common electrodes 32 are alternately stacked in the upward direction. . As shown in FIG. 2, the individual electrode 31 and the common electrode 32 are alternately arranged so as to face each other across the seven piezoelectric sheet layers 35 excluding the lowermost and uppermost piezoelectric sheet layers 35. Placed in. Each of the piezoelectric sheet layers 35 has a thickness of about 30 μm and is disposed over the plurality of pressure chambers 19.

  As shown in FIG. 1, surface electrodes 33 and 34 are formed on the uppermost surface of the actuator 30. The surface electrodes 33 and 34 are formed corresponding to the individual electrode 31 and the common electrode 32 shown in FIG. The surface electrodes 33 and 34 shown in FIG. 1 are electrically connected to the individual electrode 31 and the common electrode 32 through a conductive material filled in a through hole (not shown) of the actuator 30. The lowermost surface of the actuator 30 is joined to the ink permeation protective layer 20 with an adhesive or the like. At this time, the actuator 30 is joined so that the individual electrode 31 is disposed at the same position as the pressure chamber 19 in the vertical direction.

  The flexible wiring member 40 is provided with a wiring pattern for transmitting a control signal from the outside. Specifically, the individual terminal 41 corresponding to the surface electrode 33, the common terminal 42 corresponding to the surface electrode 34, and a drive IC chip 43 that houses a drive circuit mounted on the flexible wiring member 40, The wiring 44 extending from the driving IC chip 43 and the common potential conducting wire 45 formed along the outer periphery of the flexible wiring member 40 are disposed. In the flexible wiring member 40, the wiring 44 and the common potential conducting wire 45 are electrically connected to the actuator 30 by being connected to the terminals 41 and 42, respectively.

  The driving IC chip 43 applies a voltage having a potential difference between the individual electrode 31 and the common electrode 32 so as not to cause an ink electroosmosis phenomenon in the cavity unit 10, and the corresponding ink permeation protection layer 20. Is selectively displaced. Due to the displacement, the volume of the pressure chamber 19 is changed, and ink passing through the ink chamber 18 is ejected from the nozzle port 17. In the first embodiment, a positive potential is applied to the individual electrode 31 and a ground potential is applied to the common electrode 32.

  FIG. 3 is a cross-sectional view showing a specific configuration of the ink permeation protective layer 20 shown in FIG. The ink permeation protection layer 20 is provided between the cavity plate 16 and the lowermost surface of the piezoelectric sheet 35. In the ink permeation protection layer 20, the stress relaxation layers 21a to 21d are stacked upward over four layers, and the plurality of stop members 22 to 24 are disposed between the stress relaxation layers 21a to 21d. . Specifically, as shown in FIG. 3, a first layer stop member 22 is disposed between the stress relaxation layers 21a and 21b, and a second layer stop member 23 is disposed between the stress relaxation layers 21b and 21c. The third layer stop member 24 is disposed between the stress relaxation layers 21c and 21d. Each of the stress relaxation layers 21a to 22d has a thickness of about 1 to several micrometers, and is composed of polyimide (PI), polyurethane (PU), polypropylene (PP), polyethylene (PE), and polyparaxylylene (PPX). A resin material having a low water absorption such as cyclic polyolefin (COP) is used. Each of the stop members 22 to 24 has a thickness of about 1 μm or less, and is formed of a silica-based oxide film, a silica-based nitride film, a DLC (Diamond Like Carbon) film, or the like. Specifically, SiO2, SiN, SiCN or the like is used. As the thickness of each of the stop members 22 to 24 is reduced, a step with respect to each of the stress relaxation layers 21 a to 21 d laminated between the stop members 22 to 24 is less likely to occur, and displacement due to driving of the actuator 30 is less likely to occur. Easy to be transmitted to the pressure chamber 19. In the first embodiment, the first layer stop member 22, the second layer stop member 23, and the third layer stop member 24 show an example of the stop layer of the present invention, and the stop member The stress relaxation layers 21a to 21d provided in the vertical direction of 22 to 24 show an example of a stress relaxation layer that sandwiches the surface on the piezoelectric element portion side and the surface on the pressure chamber side of the stop layer of the present invention. .

  Each of the stop members 22 to 24 is arranged according to a predetermined arrangement rule with reference to the pressure chamber 19 and the individual electrode 31 positioned corresponding to each other. Each of the stop members 22 to 24 is disposed in a region 26 sandwiched between the pressure chamber 19 and the individual electrode 31 shown in FIG. Specifically, when projected upward from the pressure chamber 19 side or downward from the individual electrode 31 side, the positions where the stop members 22 to 24 are arranged do not coincide with each other. The positions of are shifted. When the surface of the pressure chamber 19 that is in contact with the stress relaxation layer 21a is an open surface, the opening of the pressure chamber 19 is projected from the pressure chamber 19 side upward or from the individual electrode 31 side downward. Each stop member 22-24 is arrange | positioned so that the surface may be in the state where all the said stop members 22-24 were block | closed.

  4A to 4C are projection views showing arrangement states of the respective stop members 22 to 24 with respect to the open surface of the pressure chamber 19 when projected downward from the individual electrode 31 side shown in FIG. Each of the stop members 22 to 24 in FIGS. 4A to 4C has a regular hexagonal shape, and the length from one side of the regular hexagon to the other side parallel to the one side defines the pressure chamber 19. The size is subdivided to be smaller than the space in the front-rear direction of the wall. Hereinafter, the arrangement of each of the stop members 22 to 24 will be specifically described.

  FIG. 4A is a diagram showing the arrangement relationship between the pressure chamber 19 and the first layer stop member 22 in FIG. 3. For convenience of explanation, in FIG. 4A, a center line 19a extending in the left-right direction of the pressure chamber 19 (longitudinal direction of the pressure chamber 19) and a wall partitioning the pressure chamber 19, the center line 19a The upper wall lines 19b and 19c provided symmetrically in the longitudinal direction are set, and the arrangement of the first layer stop member 22 will be described.

  FIG. 4A is a region 26 sandwiched between the pressure chamber 19 and the individual electrode 31 shown in FIG. 3 and is a view in which first layer stop members 22a to 22h are arranged on the stress relaxation layer 21a. . Specifically, the first layer stop members 22a and 22b are arranged above the center line 19a. The first layer stop members 22c, 22d and 22e are disposed on the wall top line 19b. The first layer stop members 22f, 22g, and 22h are disposed on the upper wall line 19c. The first layer stop member 22c is arranged in parallel with the first layer stop member 22f in the front-rear direction. The first layer stop member 22d is arranged in parallel with the first layer stop member 22g in the front-rear direction. The first layer stop member 22e is disposed in parallel with the first layer stop member 22h in the front-rear direction. The first layer stop member 22a is disposed at a position surrounded by the four first layer stop members 22c, 22d, 22f, and 22g. The first layer stop member 22b is disposed at a position surrounded by the four first layer stop members 22d, 22e, 22g, and 22h. The intervals between the two stop members 22 a to 22 h arranged opposite to each other may be narrower than the interval between the upper wall line 19 b and the upper wall line 19 c on the wall defining the pressure chamber 19. On the stress relaxation layer 21a, the first-layer stop members 22c to 22h are arranged above the space other than the region where the first-layer stop members 22a and 22b are arranged, so that the pressure chamber 19 is arranged efficiently and at equal intervals. The center line 19a in the first embodiment is an example of a plurality of straight lines and a specific straight line according to the present invention, and the on-wall lines 19b and 19c provided symmetrically with respect to the center line 19a are the present invention. It is an example of a plurality of straight lines and adjacent straight lines.

  FIG. 4B shows that the second layer stop member 23 is displaced from the first layer stop members 22a to 22h in FIG. 4A in the region 26 shown in FIG. FIG. In FIG. 4A, two vertical lines 19d and 19e that are perpendicular to the center line 19a and divide equally between the center of the first layer stop member 22a and the center of the first layer stop member 22b. Is provided. The second layer stop member 23 has the same arrangement pattern as the arrangement of the first layer stop members 22a to 22h shown in FIG. 4A, and one of the second layer stop members 23 is the second layer stop member 23. The layer stop member 23 is disposed so as to be provided on the vertical line 19e. As shown in FIG. 4B, in the upward direction of the pressure chamber 19, the seven second-layer stop members 23 are in the upward direction at positions over the plurality of first-layer stop members 22 a to 22 h. It arrange | positions through the stress relaxation layer 21b. Each of the second layer stop members 23 is arranged on the center line 19a and the wall top lines 19b and 19c at the same interval as the first layer stop member 22 shown in FIG. 4A. In FIG. 4B, the second layer stop member 23a fills a gap surrounded by the first layer stop member 22b, the first layer stop member 22d, and the first layer stop member 22g. It arrange | positions in the upper direction of the position over the said stop members 22b, 22d, and 22g of each three 1st layers. Similarly, the other stop members 23 of the second layer are also arranged across the three first layer stop members 22 so as to fill a gap surrounded by the three first layer stop members 22. Is done.

  FIG. 4C is the region 26 shown in FIG. 3, and a plurality of the first layers are disposed above the region where the first layer stop member 22 and the second layer stop member 23 shown in FIG. 4B are not provided. FIG. 6 is a view in which a third layer stop member 24 is laminated via the stress relaxation layer 21c. The third layer stop member 24 has the same arrangement pattern as the arrangement of the first layer stop member 22 and the second layer stop member 23 shown in FIG. Of these, one third-layer stop member 24 is disposed on the vertical line 19e. In FIG. 4C, the six third layer stop members 24 are arranged in the upward direction of the second layer stop member 23 via the stress relaxation layer 21c, and the first layer stop member 22 and the second layer. It is arranged corresponding to the area of the open surface that is not filled with the eye stop member 23. The arrangement of the third layer stop member 24 is the same as the arrangement of the first layer stop member 22 and the second layer stop member 23 shown in FIGS. 4A and 4B, and the first layer stop member. 22 and the second layer stop member 23 are arranged above the center line 19a and the upper wall lines 19b and 19c at the same interval.

  Specifically, in FIG. 4C, the area of the open surface of the pressure chamber 19 in which the six third layer stop members 24 are not filled with any of the plurality of second layer stop members 23. It is arranged in the upward direction. The third layer stop member 24a is a gap surrounded by the first layer stop member 22d, the first layer stop member 22g, and the first layer stop member 22a. Through the stress relaxation layer 21c so as to close the region where the second layer stop member 23 is not provided when projected downward from the pressure chamber 19 in a direction perpendicular to the open surface of the pressure chamber 19. Be placed. Similarly, the other stop member 24 of the third layer is a gap surrounded by the three first layer stop members 22 and closes a region where the second layer stop member 23 is not provided. Thus, it arrange | positions through the said stress relaxation layer 21c.

  As described above, the first layer stop member 22 disposed between the stress relaxation layers 21a and 21b, the second layer stop member 23 disposed between the stress relaxation layers 21b and 21c, and the When the third layer stop member 24 disposed between the stress relaxation layers 21c and 21d is projected downward from the individual electrode 31 side, the open surface in a state of being laminated in the upward direction is As shown to FIG. 4C, it arrange | positions so that all the area | regions of an open surface may be block | closed by each said stop member 22-24. In the first embodiment, the second layer stop member 23 and the third layer stop member 24 filling the entire area of the open surface of the pressure chamber 19 have no gap in the pressure chamber in the present invention. It is an example of the stop member of the other stop layer arrange | positioned.

  In the first embodiment, the ink permeation protective layer 20 is disposed such that the stress relaxation layer 21a is in contact with the cavity plate 16 and the pressure chamber 19, and the stress relaxation layer 21d is in contact with the actuator 30. A plurality of the stop members 22 to 24 are arranged in three layers at a predetermined interval between the relaxing layers 21a to 21d, so that all the open surfaces are blocked. With this configuration, when the piezoelectric inkjet head 1 is manufactured, even if a force is applied to the actuator 30 or the ink permeation protection layer 20, the possibility that the ink permeation protection layer 20 is damaged can be suppressed. An electrical short circuit between the electrode 31 and the common electrode 32 can be prevented. In addition, since the open surface is covered with the plurality of stop members 22 to 24 that are smaller than the pressure chamber 19, there is no possibility that displacement due to the driving of the actuator 30 is hindered by the walls that define the pressure chamber 19. The displacement is reliably transmitted to the pressure chamber 19, and ink can be ejected from the nozzle port 17. The first layer stop member 22 in Embodiment 1 is an example of a stop member of the first stop layer of the present invention, and the second layer stop member 23 is a stop member of the second stop layer of the present invention. The third layer stop member 24 is an example of a stop member of the third stop layer of the present invention.

[Production method]
Next, a method for manufacturing the piezoelectric inkjet head 1 according to the first embodiment will be described. When the ink permeation protection layer 20 is formed, the flexible wiring member 40 is already bonded to the actuator 30. In the first embodiment, the ink permeation protection layer 20 is configured to be laminated in order from the surface of the actuator 30 on the side where the flexible wiring member 40 is not provided. Hereinafter, a method for manufacturing the piezoelectric inkjet head 1 of Embodiment 1 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a flowchart showing a manufacturing procedure of the ink permeation protective layer 20 in the first embodiment. FIG. 5B is a diagram showing changes in the ink permeation protective layer 20 corresponding to the manufacturing procedure flow shown in FIG. 5A. In the method for manufacturing the piezoelectric inkjet head 1 according to the first embodiment, as shown in FIG. 5B, the ink permeation protective layer 20 is formed on the side of the actuator 30 where the flexible wiring member 40 is not provided. . FIG. 5B shows the piezoelectric inkjet head 1 shown in FIG. In the piezoelectric ink jet head 1 according to the first embodiment, the pressure chamber 19 and the individual electrode 31 are provided corresponding to each other, and as shown in FIG. The length is substantially equal to the length of the individual electrode 31 in the left-right direction, and the size of the open surface is substantially equal to the size of the region of the individual electrode 31. That is, the piezoelectric ink jet head 1 will be described below assuming that the pressure chambers 19 and the individual electrodes 31 are stacked in the same position in the left-right direction as shown in FIG.

  The method for forming the ink permeation protective layer 20 shown in FIG. 5B includes chemical vapor deposition (plasma, heat, light and laser CVD), sputtering (direct current, high frequency, magnetron and ion sputtering) and physical vapor. A coating formation method such as a phase growth method (vacuum and low-pressure atmosphere deposition method) can be used. In the first embodiment, a predetermined CVD gas is filled in one CVD apparatus (not shown) by plasma CVD, and the stress relaxation layers 21a to 21d and the stop members 22 to 24 are covered and synthesized, and the ink A method for forming the permeation protective layer 20 will be described. Different apparatuses may be used for the CVD apparatus for forming the stress relaxation layers 21a to 21d and the CVD apparatus for forming the stop members 22 to 24, respectively. Each of the stop members 22 to 24 faces the stress relaxation layers 21a to 21d through a masking member (not shown) for forming each of the plurality of stop members 22 to 24 arranged separately from each other. It is formed. The masking member is a plate-like member provided with a number of regular hexagonal holes in accordance with the arrangement of the first layer stop members 22 shown in FIG. 4A. Hereinafter, the manufacturing method of the piezoelectric inkjet head 1 will be described according to the manufacturing procedure flowchart shown in FIG. 5A.

  In step S1 shown in FIG. 5A, the stress relaxation layer 21d is formed by plasma CVD on one surface of the piezoelectric sheet layer 35 on the side where the flexible wiring member 40 is not bonded. Specifically, in a plasma CVD apparatus adjusted to a vacuum, the raw material evaporation source diamine and tetracarboxylic dianhydride are supplied, and the temperature and pressure are adjusted, followed by heat treatment. When the heat treatment is performed, the raw material evaporation source is turned into plasma and becomes polyamic acid, which is generated on one surface of the piezoelectric sheet layer 35. Thereafter, when the polyamic acid is heated to 350 ° C. in nitrogen, it becomes an imidized polyimide film, and the stress relaxation layer 21d is formed. FIG. 5B (1) shows a state in which step S1 is performed and the stress relaxation layer 21d is disposed on the actuator 30. FIG. After the stress relaxation layer 21d is formed, the process of step S2 is performed thereafter. In the first embodiment, the one surface indicates the entire region of the piezoelectric sheet layer 35.

  In step S2 shown in FIG. 5A, a plurality of third layer stop members 24 are arranged on the stress relaxation layer 21d. Specifically, in FIG. 5B, the masking member is temporarily provided on the stress relaxation layer 21d, and TEOS (tetraethoxysilane) gas, which is a raw material of the stop member 24, is plasma CVD method through the masking member. A process of turning into plasma is performed, and a silicon dioxide film is formed. When the silicon dioxide film is formed, the masking member is removed. When the process of step S2 is performed, the third layer stop member 24 is arranged in the state shown in (2) of FIG. 5B. Each of the third layer stop members 24 is disposed so as not to cross two opposing sides of the individual electrode 31, and at least one of them is disposed in a region corresponding to the individual electrode 31.

  In step S3, the stress relaxation layer 21c is disposed on one surface of the stress relaxation layer 21d provided with the third layer stop member 24. The method of forming the stress relaxation layer 21c and the later described stress relaxation layers 21a to 21b is substantially the same as the method of forming the stress relaxation layer 21d, and thus detailed description thereof is omitted. When the process of step S3 is performed, the stress relaxation layer 21c is arranged in a state shown in (3) of FIG. 5B. After the stress relaxation layer 21c is formed, the process of step S4 is performed thereafter.

  In step S4, the second layer stop member 23 is disposed on the stress relaxation layer 21c. The method of forming the second layer stop member 23 and the first layer stop member 22 to be described later is substantially the same as the method of forming the third layer stop member, and detailed description thereof will be omitted. . When the process of step S4 is performed, the second layer stop member 23 is arranged in the state shown in FIG. 5B (3). In consideration of the arrangement of the third layer stop member 24 in step S3, the second layer stop member 23 is arranged on the individual electrode 31 so that at least one of the second layer stop members 23 straddles between the third layer stop members 24. Arranged in the corresponding area.

  In step S5, the stress relaxation layer 21b is disposed on one surface of the stress relaxation layer 21c provided with the second layer stop member 23. When the process of step S5 is performed, the stress relaxation layer 21c is arranged in the state shown in FIG. 5B (3). After the stress relaxation layer 21b is formed, the process of step S6 is performed thereafter.

  In step S6, the first layer stop member 22 is disposed on the stress relaxation layer 21b. When the process of step S6 is performed, the first layer stop member 22 is arranged in the state shown in FIG. 5B (3). At least one first layer stop member 22 is disposed in a region corresponding to the individual electrode 31 in the same manner as the second layer stop member 23 in step S3.

  In step S <b> 7, the stress relaxation layer 21 a is formed on one surface of the first layer stop member 22. When the process of step S7 is performed, the stress relaxation layer 21a is arranged in the state shown in FIG. 5B (4). When the processing of steps S1 to S7 is performed, the stress relaxation layers 21a to 21d and the stop members 22 to 24 are alternately stacked, and the ink permeation protection layer 20 is formed.

  In step S8, the cavity unit 10 is positioned on the stress relaxation layer 21a and bonded by the adhesive 25. Specifically, the cavity plate 16 is positioned and disposed such that two opposing sides of the wall defining the pressure chamber 19 do not cross the first layer stop members 22a to 22h. When the process of step S8 is performed in the state of FIG. 5B (5), the relationship among the positions where the cavity unit 10, the ink permeation protective layer 20, and the actuator 30 are arranged is as shown in FIG. 5B (6). It is the state shown in.

  6A shows the arrangement of the stop members 22 to 24 on the left and right front and rear planes in a region corresponding to the open surface of the pressure chamber 19 with respect to the ink permeation protection layer 20 according to the first embodiment. It is the top view seen from 31 side. FIG. 6B is a cross-sectional view corresponding to the top view and showing the arrangement of the stop members 22 to 24 corresponding to the pressure chamber 19 in the vertical direction. According to the first embodiment, as shown in FIGS. 6A and 6B, the ink permeation protection layer 20 is opened to the pressure chamber 19 by the stop members 22 to 24 in the left and right front and rear planes and the vertical direction. It is possible to cover the entire surface. In the first embodiment, the region corresponding to the individual electrode 31 and the region corresponding to the pressure chamber 19 are the same region, and the region 26 sandwiched between the pressure chamber 19 and the individual electrode 31 shown in FIG. It is.

  In the method for manufacturing the ink permeation protective layer 20 of the first embodiment described above, the stop members 22 to 24 are closely attached to a surface on which the stop members 22 to 24 are laminated with a predetermined mesh-shaped masking member. However, the present invention is not limited to this. As a method of forming the stop members 22 to 24 other than the above, the stop members 22 to 24 are formed on the entire surface on which the stop members 22 to 24 are laminated without using the masking member, and then plasma etching is performed. Alternatively, the stop members 22 to 24 may be formed by partial removal by a method or a laser processing method.

  The stress relaxation layers 21a to 21d are not limited to the plasma CVD method described above, and may be formed by a spray coating method, a thermal decomposition CVD method, or the like. As an example of the spray coating method, there is a method in which a droplet of polyamic acid is applied together with a compressed spray gas and subjected to heat treatment at a high temperature for a certain period of time to imidize to form a polyimide film. As an example of the thermal decomposition CVD method, there is a method in which polyparaxylylene is laminated on the substrate and generated by sublimating and thermally decomposing diparaxylylene on the substrate set in the thermal decomposition CVD apparatus. When the stress relaxation layers 21a to 21d are formed by a spray coating method, the stop members 22 to 24 formed by a plasma CVD method and the stress relaxation layers 21a to 21d formed by a spray coating method are the respective layers. Are formed separately and alternately.

<Embodiment 2>
Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings. The second embodiment is different from the first embodiment in that the shape of each stop member constituting the ink permeation protective layer is different. The second embodiment is the same as the first embodiment with respect to the configuration and manufacturing method of the other parts, so only the different configuration will be described in detail, and the description of the same configuration as the first embodiment will be omitted.

  7A and 7B show the arrangement of the respective stop members 122 to 124 of the ink permeation protection layer 120 in the second embodiment. Each of the stop members 122 to 124 has a round shape and a curved shape convex toward the actuator 30 side. Since each of the stop members 122 to 124 has a height in the vertical direction, it is possible to lengthen the liquid permeation path and reduce the possibility of a short circuit of the piezoelectric element portion. FIG. 7A is a top view showing the arrangement of the respective stop members 122 to 124 in the left and right front and rear planes. FIG. 7B corresponds to a top view and is a cross-sectional view showing the arrangement of the stop members 122 to 124 in the vertical direction.

  As shown in FIG. 7A, each of the stop members 122 to 124 is configured such that the radius of the round shape is smaller than the interval between the wall upper line 19 b and the wall upper line 19 c on the wall that partitions the pressure chamber 19. As described above, each of the stop members 122 to 124 has a height, but is configured to be smaller than the interval between the two wall top lines 19b and 19c, so that the displacement due to the driving of the actuator 30 is transferred to the pressure chamber 19. I can tell you with certainty. Moreover, even if each stop member 122-124 is circular shape, the said open surface of the said pressure chamber 19 is covered with three layers similarly to the case of the regular hexagonal stop members 22-24 of Embodiment 1. Is possible.

  As shown in FIG. 7B, each of the round-shaped stop members 122 to 124 in Embodiment 2 has a convex curved shape whose height in the vertical direction is about 1 to several μm on the side where the actuator 30 is joined. I am doing. The stop members 122 to 124 increase the film forming temperature in the range of 200 ° C. to 400 ° C. at the time of manufacture, thereby increasing the film stress in the compression direction and increasing the amount of warpage. Each of the stop members 122 to 124 warps in a concave shape when compressed. When this is used to heat-treat each of the stop members 122 to 124, a convex shape can be formed in a desired direction in the vertical direction. The ink permeation protection layer 120 includes the stop members 122 to 124 having the same number of layers as in the first embodiment. However, the ink penetration protection layer 120 has a height between the cavity unit 10 and the actuator 30 in the vertical direction. The liquid permeation path can be lengthened. With this configuration, even when ink permeates into the ink permeation protective layer 120, the possibility that the individual electrode 31 and the common electrode 32 of the actuator 30 are short-circuited can be reduced.

<Embodiment 3>
Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings. The third embodiment is different from the first embodiment in that the shape and arrangement of the stop members constituting the ink permeation protection layer and the number of stacked layers are different. The third embodiment is the same as the first embodiment with respect to the configuration and manufacturing method of the other parts, so only the different configuration will be described in detail, and the description of the same configuration as the first embodiment will be omitted.

  FIG. 8 is a diagram showing the arrangement of the ink permeation protection layer 220 in the third embodiment. In FIG. 8, the ink permeation protection layer 220 has four layers of stop members 222 to 225 that are alternately laminated between five stress relaxation layers (not shown). Each of the stop members 222 to 225 is arranged in a positional relationship in which all sides face the sides of the other stop members 222 to 225 above the center lines 19a, 19b, and 19c of the pressure chamber 19. . 8A and 8B show the arrangement of the stop members 222 to 225 of the ink permeation protection layer 220. FIG. FIG. 8A is a top view showing the arrangement of the stop members 222 to 225 on the left and right front and rear planes. FIG. 8B is a cross-sectional view corresponding to the top view and showing the arrangement of the stop members 222 to 225 in the vertical direction.

  As shown in FIG. 8A, each of the stop members 222 to 225 has a regular square shape, and the length of each side is smaller than the interval between the wall upper lines 19b and 19c of the wall defining the pressure chamber 19. is there. As shown in FIG. 8B, each of the stop members 222 to 225 is disposed so as to straddle the gap between the two stop members 222 to 225 in the other layer. For this reason, the possibility that the liquid permeates in the region corresponding to the open surface of the pressure chamber 19 is the same regardless of the position, and the entire region of the open surface corresponding to the pressure chamber 19 is electrically The possibility of short circuiting is reduced.

[Modification 1]
In the first embodiment, the shape of each of the stop members 22 to 24 is a regular hexagonal shape, but is not limited thereto. For example, it may be an even number of polygons with more corners than hexagons. In the first embodiment, the shape and size of the second layer stop member 23 and the third layer stop member 24 are the same as those of the first layer stop member 22, but are not limited thereto. If the second layer stop member 23 and the third layer stop member 24 have a shape that can cover the region where the pressure chamber 19 cannot be covered by the first layer stop member 22, It may be smaller than the first layer stop members 22 to 24, and may have a shape different from that of the first layer stop member 22. The stop members 22 to 24 may have a curved shape that is convex toward the cavity unit 10.

  In the first embodiment, the ink permeation protection layer 20 includes the three stop members 22 to 24, but is not limited thereto. Although the conditions vary depending on the arrangement and shape of the pressure chamber 19 and the individual electrode 31, the stop member is configured by at least two layers as long as the entire open surface of the pressure chamber 19 can be covered. May be. Further, the number of layers is not limited to less than three layers, and the number of layers may be three or more, for example, four or five layers. Further, each of the stop members 22 to 24 in Embodiment 1 is provided on the entire surface of the ink permeation protection layer 20 as long as it is provided at least in the region 26 sandwiched between the pressure chamber 19 and the individual electrode 31. There is no need to be provided.

[Modification 2]
In the first embodiment, the method of manufacturing the ink permeation protective layer 20 is a method of stacking from the actuator 30 side to the cavity unit 10 side, but is not limited thereto. For example, each of the stop members 22 to 24 is provided on one surface of the film-like stress relaxation layer 21 in the vertical direction, or is provided on both surfaces so that the layers of the stop members 22 to 24 are not opposed to each other. A stress relaxation stop layer set having a configuration is positioned and arranged on the actuator 30, a plurality of other stress relaxation stop layer sets are stacked, and then the cavity unit 10 is positioned and bonded, whereby the ink permeation is performed. The protective layer 20 may be formed. In the first embodiment, each layer of the ink permeation protective layer 20 is formed by a vapor deposition method using a plasma CVD method as an example, but may be formed by a known vapor deposition method, coating, baking, or the like.

DESCRIPTION OF SYMBOLS 1 Piezoelectric ink jet head 10 Cavity unit 19 Pressure chamber 19a Center line 19b, 19c Wall line 20, 120, 220 Ink permeation protection layer 21a-21d Stress relaxation layer 22a-22h First layer stop member 23 Second layer stop member 24 3 Layer stop member 30 Actuator 31 Individual electrode 32 Common electrode 122-124, 222-225 Stop member

Claims (9)

A droplet ejecting section having a pressure chamber connectable to a liquid supply source;
A piezoelectric element that pressurizes the pressure chamber;
A liquid permeation protection unit disposed between the piezoelectric element unit and the droplet ejection unit,
The liquid permeation protector is
A stop layer composed of a plurality of layers for preventing liquid from the pressure chamber from penetrating into the piezoelectric element portion;
The piezoelectric element portion side surface and the pressure chamber side surface of at least each of the stop layers disposed in the region facing the piezoelectric element portion, the stop layer, and the region facing the pressure chamber are sandwiched, respectively. A stress relaxation layer to be worn,
The stop layer is composed of a plurality of subdivided stop members,
The stop member of the one stop layer is disposed so as to cover the pressure chamber by a plurality of stop members, and is stacked on the surface of the pressure chamber facing the one stop layer. The droplet ejecting head is characterized in that the stop members are arranged without gaps. The piezoelectric element portion is composed of an individual electrode smaller than the pressure chamber arranged corresponding to the pressure chamber, and a common electrode facing the individual electrode,
The droplet ejecting head according to claim 1, wherein at least one of the stop members of the one stop layer is disposed in a region corresponding to the individual electrode and the pressure chamber.   Each stop member of the stop layer closest to the pressure chamber is disposed so as to cover a part of the pressure chamber without crossing at least two opposing sides of the wall defining the pressure chamber. The droplet ejecting head according to claim 1 or 2.   Each stop member of the stop layer closest to the individual electrode is disposed so as to cover a part of the individual electrode without crossing at least two opposing sides of the individual electrode. Item 2 or 3 droplet ejection head. The plurality of stop members arranged in the one stop layer,
The liquid droplet ejecting head according to claim 1, wherein the liquid droplet ejecting head is arranged at an interval narrower than a size of the stop member. The stop layer has a three-layer structure in which a plurality of stop members having the same shape are arranged along a plurality of straight lines extending in parallel with the surface direction of the stop layer,
The stop member of the first stop layer is disposed so as to cover the pressure chamber;
The stop member of the second stop layer is arranged to cover a connection portion between the stop members of the first stop layer;
The stop member of the third stop layer is a connection part between the stop members of the first stop layer, and is arranged to cover the connection part that is not covered by the stop member of the second stop layer.
The liquid droplet ejecting head according to claim 1, wherein:   The droplet ejection according to claim 6, wherein the stop layer is disposed such that a stop member disposed on a specific straight line is in contact with two stop members disposed on adjacent straight lines. head.   The droplet ejecting apparatus according to claim 1, wherein the stop member has a convex shape in the piezoelectric element portion direction or the droplet ejecting portion direction. In the manufacturing method of the droplet jet head according to claim 1,
Each of the stop layers formed of a plurality of layers of the droplet permeation protection unit is laminated in order from the piezoelectric element unit side to the droplet ejection unit side.