JP2009119647A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head which is prevented from being influenced by an external environment such as humidity, and high in reliability. <P>SOLUTION: The inkjet recording head having nozzle holes which eject inks, a nozzle substrate where pressure generation chambers communicating with the nozzle holes are formed, piezoelectric elements which are set on one surface of the nozzle substrate to make the pressure generation chambers generate a pressure change has a wiring board which transmits a drive signal to the piezoelectric elements, a wiring member which electrically connects the piezoelectric elements with terminals formed on the wiring board, and a sealing cap which seals terminals and the wiring member by covering the piezoelectric elements. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording head.

  Since the droplet discharge method (inkjet method) can form a high-definition image, its application is further expanded and it has been proposed to be used not only for image formation but also for the manufacture of microdevices. In this droplet discharge method, a functional liquid (ink) containing a material for forming wiring in a semiconductor device is formed into droplets and discharged from a droplet discharge head (inkjet recording head), and a desired liquid is ejected onto a substrate. This is a method of forming a wiring pattern.

  Usually, the droplet discharge head includes a nozzle substrate that includes a nozzle hole that discharges a functional liquid, a pressure generation chamber that communicates with the nozzle hole, and a communication portion (ink supply path) that continues between the pressure generation chambers; The nozzle substrate is composed of a piezoelectric element provided on one surface side of the nozzle substrate and a driver IC (semiconductor element) for driving the piezoelectric element. The piezoelectric element and the driver IC are electrically connected using a bonding wire or the like. Is connected to.

In the droplet discharge head having such a configuration, in order to prevent the piezoelectric element from being deteriorated by the influence of external moisture or the like, a configuration in which a sealing member that seals the piezoelectric element and blocks it from the external environment is provided. Is known (for example, see Patent Document 1).
JP 2007-62035 A

  By the way, in the droplet discharge head configured as described above, not only the piezoelectric element but also the bonding wire connecting the piezoelectric element and the driver IC is greatly affected by external moisture and deteriorates over time. . However, the droplet discharge head described in Patent Document 1 is configured to seal only the piezoelectric element, and the bonding wire is disposed in an external environment. For this reason, there is a problem that the bonding wire deteriorates due to the influence of external moisture and the reliability of the apparatus is greatly impaired.

  SUMMARY An advantage of some aspects of the invention is that it provides a highly reliable ink jet recording head without being affected by an external environment such as moisture.

  The above object is achieved by the invention described in any one of 1 to 7 below.

1. A nozzle hole for discharging ink, a nozzle substrate having a pressure generation chamber communicating with the nozzle hole, and
In an ink jet recording head provided with a piezoelectric element provided on one surface of the nozzle substrate and causing a pressure change in the pressure generating chamber,
A wiring board that transmits a drive signal to the piezoelectric element;
A wiring member for electrically connecting the piezoelectric element and a terminal portion provided on the wiring board;
An ink jet recording head comprising: a sealing cap that covers and seals the piezoelectric element, the terminal portion, and the wiring member.

2. The sealing cap is formed with an opening through which the wiring board is inserted,
2. The ink jet recording head according to item 1, wherein an inner surface of the opening and the wiring board are bonded with a resin interposed therebetween.

  3. 3. The ink jet recording head according to item 1 or 2, wherein the wiring board is a flexible printed wiring board.

  4). 4. The ink jet recording head according to any one of 1 to 3, wherein the wiring member is a bonding wire.

  5). The ink jet recording head according to any one of 1 to 4, wherein a material of the sealing cap is resin or metal.

  6). 6. The ink jet recording head according to any one of 1 to 5, wherein the sealing cap is formed with heat radiating fins.

7). The nozzle substrate is
A nozzle plate having nozzle holes for discharging ink;
The inkjet according to any one of 1 to 6, further comprising: a pressure generation chamber communicating with the nozzle hole; and a body plate having an ink supply path for supplying ink to the pressure generation chamber. Recording head.

  According to the present invention, a piezoelectric element, a terminal part provided on a wiring board that transmits a drive signal to the piezoelectric element, and a wiring member that electrically connects the piezoelectric element and the terminal part of the wiring board are sealed. It was set as the structure covered with a cap and sealed.

  In other words, the piezoelectric element, the terminal portion of the wiring board, and the wiring member, which are easily deteriorated by the influence of the external environment such as moisture, are covered and sealed with a sealing cap, so that the external environment is highly reliable. An ink jet recording head can be realized.

  Hereinafter, an embodiment of an ink jet recording head (hereinafter abbreviated as a recording head) according to the present invention will be described with reference to the drawings. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not limited to this embodiment.

  First, the configuration of a recording head according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the recording head 1 as viewed from below, and FIG. 2 is a diagram in which the AA ′ side cross section in FIG.

  As shown in FIGS. 1 and 2, the main part of the recording head 1 includes a nozzle substrate 5, a vibration plate 30, a reinforcing plate 40, a piezoelectric element 70, a flexible printed wiring board (hereinafter referred to as FPC) 60, and It is comprised from the sealing cap 50 grade | etc.,.

  When a drive signal is applied to the piezoelectric element 70 from an external drive circuit (not shown), the piezoelectric element 70 vibrates and excites the diaphragm 30. When the vibration plate 30 is excited, this vibration changes the pressure of a pressure generation chamber 201 formed in a body plate 20 (described later) constituting the nozzle substrate 5 and containing ink, and the nozzle hole 101 formed in the nozzle plate 10. Ink droplets are ejected from.

  The nozzle substrate 5 includes a nozzle plate 10 and a body plate 20.

  The nozzle plate 10 has a plurality of nozzle holes 101 for ejecting ink.

  A body plate 20 is disposed on the upper surface side of the nozzle plate 10. The lower surface of the body plate 20 and the nozzle plate 10 are fixed via, for example, an adhesive or a heat welding film. The body plate 20 can be made of silicon, glass, a ceramic material, or the like. In the case of the present embodiment, the body plate 20 is made of silicon.

  Inside the body plate 20, a pressure generation chamber 201, an ink supply path 202, and the like configured by joining the nozzle plate 10 and the vibration plate 30 are formed. The pressure generation chamber 201 is formed corresponding to the plurality of nozzle holes 101. The pressure generation chamber 201 stores ink and discharges ink from a plurality of nozzle holes 101 formed in the nozzle plate 10 by pressure applied when the recording head 1 is operated. The ink supply path 202 supplies ink supplied from an ink supply pipe 90 described later to the pressure generation chamber 201.

  On the other hand, a diaphragm 30 is disposed on the upper surface side of the body plate 20. The diaphragm 30 has a structure in which an elastic film 301 and a lower electrode film 302 are laminated in order from the body plate 20 side. The elastic film 301 disposed on the body plate 20 side is made of a silicon oxide film having a thickness of about 1 to 2 μm, for example, and the lower electrode film 302 is made of a metal film having a thickness of about 0.2 μm, for example. Is. In the present embodiment, the lower electrode film 302 functions as a common electrode for the plurality of piezoelectric elements 70.

  A piezoelectric element 70 for deforming the diaphragm 30 is disposed on the upper surface side of the diaphragm 30. The piezoelectric element 70 has a structure in which a piezoelectric film 701 and an upper electrode film 702 are laminated in order from the lower electrode film 302 side. The piezoelectric film 701 is made of a PZT film having a thickness of about 1 μm, for example, and the upper electrode film 702 is made of a metal film having a thickness of about 0.1 μm, for example. On the upper surface of the upper electrode film 702, a lead electrode 703 made of, for example, Au or the like for connecting to the FPC 60 is formed.

  The concept of the piezoelectric element 70 may include a lower electrode film 302 in addition to the piezoelectric film 701 and the upper electrode film 702. This is because the lower electrode film 302 functions as the piezoelectric element 70 and also functions as the diaphragm 30. In the present embodiment, a configuration in which the elastic film 301 and the lower electrode film 302 function as the diaphragm 30 is employed, but the elastic film 301 may be omitted and the lower electrode film 302 may also serve as the elastic film 301. it can. A plurality of piezoelectric elements 70 are provided so as to correspond to the plurality of nozzle holes 101 and the pressure generation chamber 201.

  A reinforcing plate 40 that reinforces the nozzle substrate 5 is disposed on the upper surface side of the vibration plate 30. FPCs 60 (wiring boards) that transmit drive signals from an external drive circuit (not shown) are disposed on both side edges of the reinforcing plate 40. A connection terminal 601 (terminal portion) for connecting to the piezoelectric element 70 is formed on the upper surface of the FPC 60. The connection terminal 601 of the FPC 60 and the lead electrode 703 of the piezoelectric element 70 are connected by a bonding wire 705 (wiring member).

  Here, a sealing cap 50 is provided on the upper surface side of the reinforcing plate 40. The sealing cap 50 is made of a resin material or a metal material, and is disposed so as to cover the piezoelectric element 70, the connection terminal 601 of the FPC 60, the bonding wire 705, and the like. And the reinforcement board 40 and the sealing cap 50 are bonded together by the contact bonding layer which consists of adhesive resin etc. which are not shown in figure. Moreover, the opening part 501 in which FPC60 is penetrated is formed in the both sides | surfaces of the sealing cap 50, and the inner surface of the opening part 501 and the upper surface of FPC60 are bonded together on both sides of the silicon resin 503. A hygroscopic agent 80 is provided on the upper surface side of the central portion of the reinforcing plate 4.

  Here, the manufacturing process of the recording head 1 according to the embodiment of the present invention will be described with reference to FIG. 3 (a) to 3 (g) are schematic views showing the manufacturing process of the recording head 1. In each of FIGS. 3 (a) to 3 (g), the upper drawing is a plan view and the drawing. The figure below shows a side cross-sectional view.

  First, the nozzle plate 10 and the body plate 20 are anodically bonded with the glass plate 15 interposed therebetween to form the nozzle substrate 5 (FIG. 3A).

  Next, the vibration plate 30 in which the elastic film 301 and the lower electrode film 302 are laminated is bonded to the upper surface side of the nozzle substrate 5 (FIG. 3B).

  Next, the piezoelectric element 70 in which the piezoelectric film 701 and the upper electrode film 702 are laminated is disposed on the upper surface side of the vibration plate 30 (FIG. 3C).

  Next, the reinforcing plate 40 is joined to the upper surface side of the vibration plate 30 (FIG. 3D).

  Next, the FPC 60 is joined to the peripheral edges on both sides of the reinforcing plate 40, and the connection terminals 601 of the FPC 60 and the lead electrodes 703 of the piezoelectric element 70 are connected by bonding wires 705 (FIG. 3E).

  Next, the sealing cap 50 is joined to the upper surface side of the reinforcing plate 40, and the piezoelectric element 70, the connection terminal 601 of the FPC 60, and the bonding wire 705 are sealed. At this time, the inner surface of the opening 501 formed on both side surfaces of the sealing cap 50 and the upper surface of the FPC 60 are bonded together with the silicon resin 503 interposed therebetween (FIG. 3F).

  Finally, the ink supply pipe 90 is connected to complete the recording head 1 (FIG. 3G).

  As described above, in the recording head 1 according to the embodiment of the present invention, the piezoelectric element 70, the connection terminal 601 provided on the FPC 60 that transmits a drive signal to the piezoelectric element 70, and the lead electrode provided on the piezoelectric element 70. 703 and the bonding wire 705 that electrically connects the connection terminal 601 of the FPC 60 are covered with the sealing cap 50 and sealed.

  That is, since the piezoelectric element 70, the connection terminal 601 of the FPC 60, and the bonding wire 705 that are easily deteriorated due to the influence of the external environment such as moisture are covered with the sealing cap 50 and sealed, the structure is shielded from the external environment. It is possible to realize an ink jet recording head having high performance.

  Further, since the reinforcing plate 40 and the sealing cap 50 are bonded together by an adhesive layer made of an adhesive resin or the like, intrusion of moisture and moisture from the interface between the sealing cap 50 and the adhesive layer is prevented. . Further, since the inner surface of the opening 501 through which the FPC 60 formed on both sides of the sealing cap 50 is inserted and the upper surface of the FPC 60 are bonded together with the silicon resin 503 interposed therebetween, the opening 501 of the sealing cap 50 is provided. Intrusion of moisture and moisture from the gap between the FPC 60 and the FPC 60 is prevented. Further, since the FPC 60 is joined by the sealing cap 50 via the silicon resin 503, disconnection due to an external load and peeling from the reinforcing plate 40 when the FPC 60 is bent are prevented.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be changed or improved as appropriate. For example, the sealing cap 50 in the present embodiment has a shape as shown in FIG. 4, but as shown in FIG. 5, the radiation fins 505 may be formed on the upper surface side of the sealing cap 50. Thereby, heat generated when the piezoelectric element 70 is driven can be released, and ink can be ejected stably.

1 is a perspective view of an ink jet recording head according to an embodiment of the present invention as viewed from below. It is a figure which shows the side cross section of an inkjet recording head. It is a figure which shows the manufacturing process of an inkjet recording head. It is a perspective view which shows the external appearance of a sealing cap. It is a perspective view which shows the external appearance by another example of a sealing cap.

Explanation of symbols

1 Inkjet recording head (recording head)
5 Nozzle substrate 10 Nozzle plate 101 Nozzle hole 15 Glass plate 20 Body plate 201 Pressure generating chamber 202 Ink supply path 30 Vibration plate 301 Elastic film 302 Lower electrode film 40 Reinforcing plate 50 Sealing cap 501 Opening 503 Silicone resin 505 Radiation fin 60 Flexible printed circuit board (FPC)
601 Connection terminal 70 Piezoelectric element 701 Piezoelectric film 702 Upper electrode film 703 Lead electrode 705 Bonding wire 80 Hygroscopic agent 90 Ink supply pipe

Claims (7)

A nozzle hole for discharging ink, and a nozzle substrate in which a pressure generation chamber communicating with the nozzle hole is formed;
In an ink jet recording head provided with a piezoelectric element provided on one surface of the nozzle substrate and causing a pressure change in the pressure generating chamber,
A wiring board that transmits a drive signal to the piezoelectric element;
A wiring member for electrically connecting the piezoelectric element and a terminal portion provided on the wiring board;
An ink jet recording head comprising: a sealing cap that covers and seals the piezoelectric element, the terminal portion, and the wiring member. The sealing cap is formed with an opening through which the wiring board is inserted,
The ink jet recording head according to claim 1, wherein an inner surface of the opening and the wiring substrate are bonded with a resin interposed therebetween. The ink jet recording head according to claim 1, wherein the wiring board is a flexible printed wiring board. 4. The ink jet recording head according to claim 1, wherein the wiring member is a bonding wire. 5. The ink jet recording head according to claim 1, wherein a material of the sealing cap is resin or metal. The ink jet recording head according to claim 1, wherein the sealing cap is formed with heat radiating fins. The nozzle substrate is
A nozzle plate having nozzle holes for discharging ink;
7. The apparatus according to claim 1, further comprising a pressure generation chamber communicating with the nozzle hole and a body plate having an ink supply path for supplying ink to the pressure generation chamber. Inkjet recording head.

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