JP2010179590A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head having less cross talk even in a high density inkjet recording head. <P>SOLUTION: This inkjet recording head includes: a nozzle plate on which a plurality of nozzle holes for discharging an ink are formed; a body plate which is bonded to the nozzle plate, and on which pressure chambers respectively communicating with the nozzle holes are formed; and a piezoelectric element which is installed on the opposite surface from the surface of the body plate to which the nozzle plate is bonded, and makes a pressure change respectively generated in the pressure chambers. The inkjet recording head also includes a reinforcing member which covers the piezoelectric element by installing a space around the piezoelectric element, and is bonded to the surface of the body plate on which the piezoelectric element is arranged. The surface of the reinforcing member which is bonded to the body plate is formed in a manner to surround the region of the body plate in which the piezoelectric element is arranged. Then, an opening is installed in a region corresponding to the piezoelectric element of the surface for covering the piezoelectric element of the reinforcing member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording head.

  Since the inkjet method can form a high-definition image, its application is further expanded.

  In general, an ink jet recording head (hereinafter also simply referred to as a recording head) has a nozzle plate in which a plurality of nozzle holes for discharging ink droplets are formed, a pressure chamber communicating with the nozzle holes, and a continuous space between the pressure chambers. A body plate having an ink supply path to be formed.

  In the recording head, a part of the pressure chamber of the body plate is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element provided thereon to pressurize the ink stored in the pressure chamber to thereby form a nozzle hole. Ink droplets are ejected from the ink.

By the way, in the recording head having such a configuration, deformation occurs even in a recording operation other than the pressure chamber being driven, and in particular, when a large number of nozzles are driven simultaneously, crosstalk or the like becomes remarkable. For this reason, the following problems arise.
・ Pressure chamber displacement loss occurs, driving efficiency decreases ・ Volume of adjacent pressure chamber not driven changes, and crosstalk occurs ・ Ink ejection characteristics change depending on the number of nozzles driven. As a method corresponding to the above, in Patent Document 1, a plate-shaped reinforcing member having an opening in a region corresponding to a vibration plate formed in a part of the pressure chamber of the body plate is used as a vibration plate of the body plate. There has been proposed a method of suppressing deformation and crosstalk of the entire recording head that occurs during recording driving by bonding to the side surface.

  Patent Document 2 proposes a method in which a reinforcing member having a configuration covering the entire piezoelectric element is provided on a flow path forming substrate (body plate).

  Patent Document 3 proposes a method of providing a thin film (reinforcing member) having a structure that covers the entire piezoelectric element by providing a space on the flow path forming substrate (body plate) so as not to hinder the movement of the piezoelectric element. Has been.

Japanese Patent Laid-Open No. 2008-940 JP 2000-296617 A JP 2001-138511 A

  By the way, in such a recording head, in recent years, higher precision and higher definition drawing performance has been required, and it is necessary to arrange more pressure chambers and piezoelectric elements in one recording head. For this reason, recording heads with higher density such as a three-row or four-row arrangement have been studied.

  However, in contrast to such a high-density recording head, in the recording head described in Patent Document 1, since the area of the opening provided in the region corresponding to the diaphragm increases, the reinforcing member and There is a problem in that the joint area with the body plate is reduced, and the effect of the reinforcing member is reduced.

  Further, in the recording head described in Patent Document 2, the reinforcing member is configured to cover the entire piezoelectric element even when the bonding area between the reinforcing member and the flow path forming substrate (body plate) is reduced due to high density. By doing so, the rigidity is increased. However, since a part of the reinforcing member is in contact with the piezoelectric element, there are problems that the movement of the piezoelectric element is hindered, the reinforcing member itself vibrates, and the entire recording head vibrates. Further, in order to connect the piezoelectric element and an external drive circuit, the upper electrode including the piezoelectric element is drawn out from a part of the reinforcing member in a predetermined direction. For this reason, there exists a problem that a member and a manufacturing process become complicated and cause a high price.

  In the recording head described in Patent Document 3, the reinforcing member is configured to cover the entire piezoelectric element by providing a space so as not to hinder the movement of the piezoelectric element. However, in this case as well, as in the case of Patent Document 2, in order to completely cover the piezoelectric element, it is necessary to provide an extraction electrode for connecting the piezoelectric element and an external drive circuit, and the same problem occurs. .

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Even in a high-density ink jet recording head, the ink jet recording head has less crosstalk without incurring high costs due to complication of members and manufacturing processes. The purpose is to provide.

  The above object is achieved by the invention described in any one of 1 to 6 below.

1. A nozzle plate having a plurality of nozzle holes for discharging ink;
A body plate formed with a plurality of pressure chambers joined to the nozzle plate and communicating with the plurality of nozzle holes, respectively;
In the ink jet recording head, comprising: a plurality of piezoelectric elements that are provided on a surface opposite to the surface to which the nozzle plate of the body plate is bonded, and cause pressure changes in the plurality of pressure chambers, respectively.
Providing a space around the plurality of piezoelectric elements to cover the plurality of piezoelectric elements, and having a reinforcing member joined to a surface of the body plate on which the plurality of piezoelectric elements are disposed;
The surface of the reinforcing member to be joined to the body plate is formed so as to surround a region of the body plate where the plurality of piezoelectric elements are disposed, and the surface of the reinforcing member that covers the plurality of piezoelectric elements is formed. An ink jet recording head, wherein an opening is provided in a region corresponding to a plurality of piezoelectric elements.

  2. 2. The ink jet recording head according to item 1, wherein the plurality of piezoelectric elements are electrically connected to a wiring board that supplies a drive signal to the piezoelectric elements through the openings.

  3. 3. The ink jet recording head as described in 2 above, wherein the plurality of piezoelectric elements and the wiring board are connected by bonding wires.

  4). 4. The ink jet recording head according to claim 1, wherein at least two rows of the pressure chambers are formed on the body plate. 5.

  5. 5. The ink jet recording head according to any one of items 1 to 4, wherein the material of the reinforcing member is a metal.

  6). 6. The ink jet recording head as described in 5 above, wherein the metal is silicon or stainless steel.

  According to the present invention, a space is provided around the plurality of piezoelectric elements to cover the plurality of piezoelectric elements, and the reinforcing member is joined to a surface on which the plurality of piezoelectric elements of the body plate are disposed, and the reinforcing member The shape of the surface joined to the body plate was set to surround a region where a plurality of piezoelectric elements of the body plate are arranged.

  That is, the shape of the reinforcing member has a two-stage configuration including a surface that joins the body plate and a surface that covers the piezoelectric element by providing a space around the piezoelectric element. As a result, the rigidity of the reinforcing member can be ensured even when the recording head has a high density such as a three-row or four-row arrangement and the joint area between the reinforcing member and the body plate is reduced. As a result, it is possible to suppress deformation and crosstalk of the entire recording head that occurs during recording driving without hindering the movement of the piezoelectric element.

  In addition, openings are provided in regions corresponding to the plurality of piezoelectric elements on the surface of the reinforcing member that covers the plurality of piezoelectric elements. Thereby, when connecting a piezoelectric element and the wiring board and drive circuit which were provided outside which supplies a drive signal to this piezoelectric element, it can connect easily through opening.

  As a result, even in a high-density ink jet recording head, it is possible to provide an ink jet recording head with little crosstalk without incurring high costs due to complication of members and manufacturing processes.

1 is a diagram illustrating a schematic configuration of an ink jet recording head according to an embodiment of the present invention. It is a schematic diagram explaining the connection method with a flexible printed wiring board.

  Hereinafter, an embodiment of an ink jet recording head according to the present invention (hereinafter abbreviated as a recording head) 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 FIG. FIG. 1A is a plan view illustrating a schematic configuration of the recording head 1, and FIG. 1B is a cross-sectional view taken along line AA ′ in FIG.

  As shown in FIG. 1, the recording head 1 includes a nozzle plate 10, an intermediate glass plate 20, a body plate 30, a piezoelectric element 50, a reinforcing member 40, and the like.

  When a drive signal is applied to the piezoelectric element 50 from an external drive circuit (not shown), the piezoelectric element 50 vibrates and excites a diaphragm 305 formed on the upper wall surface of the pressure chamber 301 of the body plate 30. When the vibration plate 305 is excited, this vibration changes the pressure of the pressure chamber 301 that is formed on the body plate 30 and stores ink, and ejects ink droplets from the nozzle holes 101a of the nozzles 101 formed on the nozzle plate 10. .

  In the nozzle plate 10, a plurality of nozzles 101 having nozzle holes 101a for discharging ink are formed.

  An intermediate glass plate 20 having a hole 20 a formed at a position corresponding to the nozzle 101 of the nozzle plate 10 is joined to the upper surface side of the nozzle plate 10.

  A body plate 30 is joined to the upper surface side of the intermediate glass plate 20. Inside the body plate 30, a pressure chamber 301, an ink supply path 303, and the like configured by joining the nozzle plate 10 and the intermediate glass plate 20 are formed. The pressure chambers 301 are respectively formed corresponding to the plurality of nozzles 101. The pressure chamber 301 accommodates ink, and a vibration plate 305 is formed on the upper wall surface.

  The pressure chamber 301 is configured to eject ink from the plurality of nozzle holes 101 a formed in the nozzle plate 10 by the pressure applied through the vibration plate 305 by the piezoelectric element 50 during the operation of the recording head 1. The ink supply path 303 supplies ink supplied from an ink supply pipe (not shown) to the pressure chamber 301.

  As materials for the nozzle plate 10 and the body plate 30, silicon, glass, a ceramic material, or the like can be used, but silicon is preferable. Further, as a material of the intermediate glass plate 20, borosilicate glass or the like can be used. For the joining of the nozzle plate 10, the intermediate glass plate 20, and the body plate 30, for example, an anodic joining technique disclosed in Japanese Patent Application Laid-Open No. 2008-940 can be used.

  A common electrode 501 that is an electrode common to the plurality of piezoelectric elements 50 is formed on the upper surface side of the body plate 30.

  The piezoelectric element 50 deforms the diaphragm 305 and corresponds to each of the plurality of diaphragms 305, and is provided on the upper surface side of the diaphragm 305 with the common electrode 501 interposed therebetween. That is, a plurality of piezoelectric elements 50 are provided so as to correspond to the plurality of nozzles 101 and the pressure chambers 301.

  The piezoelectric element 50 has a structure in which a piezoelectric film (not shown) and an electrode 503 are laminated in order from the common electrode 501 side. The common electrode 501 is made of, for example, a metal film having a thickness of about 0.2 μm, the piezoelectric film is made of, for example, a PZT film having a thickness of about 1 μm, and the electrode 503 is made of, for example, 0. It is made of a metal film having a thickness of about 1 μm. Further, on the upper surface side of the electrode 503, a lead electrode made of, for example, Au (not shown) for connecting to a flexible printed wiring board 70 (hereinafter also referred to as FPC 70) to be described later is formed.

  A reinforcing member 40 that reinforces the entire recording head 1 is bonded to the upper surface side of the body plate 30 with the common electrode 501 interposed therebetween.

  As illustrated in FIG. 1B, the reinforcing member 40 is joined to the body plate 30 so as to cover the plurality of piezoelectric elements 50 by providing spaces around the plurality of piezoelectric elements 50.

  The surface joined to the body plate 30 of the reinforcing member 40 is formed so as to surround a region A1 in which the plurality of piezoelectric elements 50 of the body plate 30 are disposed, as shown in FIG. That is, the surface joined to the body plate 30 of the reinforcing member 40 is formed in a shape corresponding to the region excluding the region A1 of the body plate 30. In addition, an opening 40 a is provided in a region A <b> 2 corresponding to the plurality of piezoelectric elements 50 on the surface of the reinforcing member 40 that covers the plurality of piezoelectric elements 50.

  As a material of the reinforcing member 40, for example, a material having high rigidity such as a metal such as stainless steel or silicon having a thickness of about 200 to 500 μm or glass, or glass can be used.

  Next, a method of connecting the piezoelectric element 50 and the FPC 70 that supplies a drive signal to the piezoelectric element 50 will be described with reference to FIG. 2A is a schematic plan view showing a connection method between the piezoelectric element 50 and the FPC 70, and FIG. 2B is a schematic cross-sectional view taken along the line AA 'in FIG. 2A.

  The FPC 70 is fixed to the end of the upper surface of the reinforcing member 40. A connection terminal (not shown) of the FPC 70 and a lead electrode (not shown) of the piezoelectric element 50 are connected by a bonding wire 701 through an opening 40 a provided in the reinforcing member 40. 2 shows the FPC 70 disposed at one end of the upper surface of the reinforcing member 40, but actually, the FPC 70 is also disposed at the other end, and the corresponding piezoelectric element 50 and bonding wire 701 are disposed. Connected by.

  As described above, in the recording head 1 according to the embodiment of the invention, the plurality of piezoelectric elements 50 of the body plate 30 are arranged by providing spaces around the plurality of piezoelectric elements 50 to cover the plurality of piezoelectric elements 50. The reinforcing member 40 is bonded to the surface, and the surface shape of the reinforcing member 40 bonded to the body plate 30 is a shape surrounding the region A1 where the plurality of piezoelectric elements 50 of the body plate 30 are disposed. It was.

  That is, the reinforcing member 40 has a two-stage configuration including a surface to be joined to the body plate 30 and a surface that covers the piezoelectric element 50 by providing a space around the piezoelectric element 50. As a result, the rigidity of the reinforcing member 40 can be ensured even when the recording head 1 has a high density, such as a three-row or four-row arrangement, and the bonding area between the reinforcing member 40 and the body plate 30 is reduced. As a result, it is possible to suppress deformation and crosstalk of the entire recording head 1 that occurs during recording driving without hindering the movement of the piezoelectric element 50.

  In addition, an opening 40a is provided in a region A2 corresponding to the plurality of piezoelectric elements 50 on the surface of the reinforcing member 40 that covers the plurality of piezoelectric elements 50. Thereby, when connecting the piezoelectric element 50 and the FPC 70 provided outside for supplying a driving signal to the piezoelectric element 50, the connection can be easily made through the opening 40a.

  As a result, even in a high-density ink jet recording head, it is possible to provide an ink jet recording head with little crosstalk without incurring high costs due to complication of members and manufacturing processes.

1 Inkjet recording head (recording head)
DESCRIPTION OF SYMBOLS 10 Nozzle plate 101 Nozzle 101a Nozzle hole 20 Intermediate glass plate 30 Body plate 301 Pressure chamber 303 Ink supply path 305 Vibration plate 40 Reinforcing member 40a Opening 50 Piezoelectric element 501 Common electrode 503 Electrode 70 Flexible printed circuit board (FPC)
701 Bonding wire

Claims (6)

A nozzle plate having a plurality of nozzle holes for discharging ink;
A body plate formed with a plurality of pressure chambers joined to the nozzle plate and communicating with the plurality of nozzle holes, respectively;
In the ink jet recording head, comprising: a plurality of piezoelectric elements that are provided on a surface opposite to the surface to which the nozzle plate of the body plate is bonded, and cause pressure changes in the plurality of pressure chambers, respectively.
Providing a space around the plurality of piezoelectric elements to cover the plurality of piezoelectric elements, and having a reinforcing member joined to a surface of the body plate on which the plurality of piezoelectric elements are disposed;
The surface of the reinforcing member to be joined to the body plate is formed so as to surround a region of the body plate where the plurality of piezoelectric elements are disposed, and the surface of the reinforcing member that covers the plurality of piezoelectric elements is formed. An ink jet recording head, wherein an opening is provided in a region corresponding to a plurality of piezoelectric elements.   2. The ink jet recording head according to claim 1, wherein the plurality of piezoelectric elements are electrically connected to a wiring board that supplies a driving signal to the piezoelectric elements through the openings.   The inkjet recording head according to claim 2, wherein the plurality of piezoelectric elements and the wiring board are connected by bonding wires.   4. The ink jet recording head according to claim 1, wherein at least two rows of the pressure chambers are formed in the body plate. 5.   The ink jet recording head according to claim 1, wherein a material of the reinforcing member is a metal.   6. The ink jet recording head according to claim 5, wherein the metal is silicon or stainless steel.

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