JP2009073081A - Liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet head capable of suppressing dispersion of liquid discharge performances of pressure generation chambers. <P>SOLUTION: A recording head includes: a passage unit 17 provided with a nozzle plate 25 provided with rows of a plurality of nozzle openings 26, a passage forming substrate 24 forming the pressure generation chambers 35 communicated with each nozzle opening 26, and an elastic plate 23 sealing the pressure generation chambers 35; and a vibrator unit 22 provided with a piezoelectric vibrator 29 applying pressure fluctuation to the pressure generation chambers 35. The recording head discharges droplets from the nozzle openings 26, the elastic plate 23 is composed by laminating film 41 and sheet metal 40, an island part 43 is formed on the metal sheet 40 facing the pressure generation chambers 35, and in a width of the island part 43 in its arranged direction, the width W2 of a piezoelectric vibrator 29 side is set larger than the width W1 of a nozzle opening 26 side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head such as an ink jet recording head, and more particularly to a liquid ejecting head that ejects liquid droplets from nozzle openings by pressure fluctuations.

  Examples of the liquid ejecting head that ejects liquid droplets from the nozzle openings by causing pressure fluctuation in the liquid in the pressure generating chamber include, for example, an ink jet type used in an image recording apparatus such as an ink jet recording apparatus (hereinafter simply referred to as a printer). Electrode materials used for forming electrodes for recording heads (hereinafter simply referred to as recording heads), color material ejecting heads used in the production of color filters such as liquid crystal displays, organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), etc. There are an ejection head, a bioorganic matter ejection head used for manufacturing a biochip (biochemical element), and the like.

  For example, in the above recording head, a pressure generating element is joined to an elastic plate that seals a hollow pressure generating chamber, and the pressure generating element is vibrated in the longitudinal direction of the pressure generating element, whereby pressure is applied to the pressure generating chamber. The liquid in the pressure generation chamber is discharged from a nozzle opening that is fluctuated and communicated with the pressure generation chamber.

  The elastic plate is formed by laminating a film and a thin metal plate. By removing a part of the thin metal plate facing the pressure generating chamber by an etching process or the like, the thin metal plate remains on the film in an island shape. An island portion is formed. And the front-end | tip of a pressure generation element is joined to the surface of this island part, ie, an elastic board, via an adhesive agent (for example, refer patent document 1).

JP 2000-94684 A

  However, when the island portion and the pressure generating element are bonded, if the bonding position accuracy of each other is poor, the pressure fluctuation of the pressure generating element is affected. . In addition, if the adhesive used to join the island part and the pressure generating element drips from between the joint surfaces, the fixed adhesive may vibrate together with the island part. There was an effect.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head capable of suppressing variations in liquid ejection performance for each pressure generating chamber.

In order to achieve the above object, a liquid jet head according to the present invention includes a nozzle forming member in which a plurality of nozzle openings are arranged, a flow path forming substrate in which a pressure generating chamber corresponding to the nozzle openings is formed, and the pressure generating chamber. An elastic plate, and a flow path unit that joins them with a flow path forming substrate in between,
An actuator unit that includes a pressure generating element that abuts on the elastic plate and applies pressure fluctuation to the pressure generating chamber;
A liquid ejecting head for ejecting liquid droplets from the nozzle opening by operation of a pressure generating element;
The elastic plate is configured by laminating a film and a thin metal plate,
An island formed on a thin metal plate facing the pressure generating chamber;
The island portion is characterized in that the width in the arrangement direction is set larger on the pressure generating element side than on the nozzle opening side.

  According to the above configuration, the elastic plate is configured by laminating the film and the metal thin plate, and includes the island portion formed on the metal thin plate facing the pressure generating chamber, and the island portion has a width in the arrangement direction and the nozzle opening. Since the width on the pressure generating element side is set larger than the width on the side, the pressure generating element is compared with the case where the width in the arrangement direction of the island portions is set smaller than the width on the nozzle opening side. It is possible to widen an allowable error when bonding to the island portion. Therefore, the required position accuracy between the pressure generating element and the island can be relaxed, the yield can be improved, and the variation in pressure fluctuation can be reduced to suppress the variation in the liquid discharge performance for each pressure generating chamber. Can do.

  In the above configuration, it is desirable that the island portion and the pressure generating element are bonded via the film.

  According to the above configuration, since the island portion and the piezoelectric vibrator are joined via the film, the piezoelectric vibrator side of the island portion is protected by the film, and when the pressure generating element is joined to the elastic plate Even if the adhesive to be used drips from between the joint surfaces, it is possible to prevent the adhesive from adhering to and sticking to the island portion. For this reason, it can prevent that an adhesive agent covers the outer periphery of an island part, and can suppress that the elasticity modulus of an elastic board changes for every pressure generation chamber which opposes an island part. Therefore, it is possible to suppress variation in the liquid discharge performance for each pressure generation chamber.

  The said structure WHEREIN: It is desirable to make the said elastic board into the structure formed by laminating | stacking the said film on both sides of the said metal thin plate.

  According to the said structure, since the film has pinched | interposed the both surfaces of the metal thin plate, since an island part is accommodated between films, an island part can be protected. For this reason, each island portion reliably transmits the pressure fluctuation caused by the pressure generating element to the pressure generating chamber, so that variation in the liquid discharge performance of each pressure generating chamber can be suppressed.

  The said structure WHEREIN: It is desirable to make the said elastic board into the structure formed by joining a film to the other surface, after etching-processing the metal thin plate which joined the film to one side.

  According to the above configuration, the elastic plate can be obtained by etching the metal thin plate with the film bonded to one surface and then bonding the film to the other surface. An elastic plate can be easily produced.

  The said structure WHEREIN: It is desirable for the said film by the side of the said pressure generating element to be provided with the air | atmosphere open hole.

  According to the above configuration, the film on the pressure generating element side is provided with an air opening hole, so that the space between the film and the outer space can be communicated with each other through the air opening hole. The volume of the space does not depend on the surrounding temperature or atmospheric pressure, and the compliance in the pressure generating chamber becomes independent of the environment.

  The said structure WHEREIN: It is desirable for the said film by the side of the said pressure generating element to be formed with the material which permeate | transmits gas.

  According to the above configuration, since the film on the pressure generating element side is formed of a material that allows gas to pass therethrough, the gas between the films can be transmitted to the outer space so that the space between the films and the outer Can maintain a balance with other spaces. As a result, the compliance in the pressure generating chamber becomes independent of the environment.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In this embodiment, an ink jet recording head (hereinafter referred to as “recording head”) will be described as an example of the liquid ejecting head.

  FIG. 1 is a perspective view of an ink jet recording apparatus. First, a schematic configuration of an ink jet recording apparatus (hereinafter referred to as a printer) equipped with a recording head in the first embodiment will be described with reference to FIG. The illustrated printer 1 is an apparatus that records an image or the like by discharging liquid ink onto the surface of a recording medium (landing target) 2 such as recording paper. The printer 1 includes a recording head 3 for ejecting ink (corresponding to a kind of liquid ejecting head in the present invention), a carriage 4 to which the recording head 3 is attached, and a carriage 4 in the main scanning direction (reference numeral X in FIG. 1). And a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction (a direction perpendicular to the main scanning direction, indicated by a symbol Y in FIG. 1). Here, the ink is a kind of liquid of the present invention, and is stored in the ink cartridge 7. The ink cartridge 7 is detachably attached to the recording head 3.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Therefore, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction X (width direction of the recording paper 2).

  Next, the configuration of the recording head 3 will be described. Here, FIG. 2 is an exploded perspective view of the recording head 3 attached to the carriage 4. The illustrated recording head 3 includes a cartridge base 15 (hereinafter referred to as “base”), a head case 16, a flow path unit 17, a vibrator unit 22 (corresponding to a kind of actuator unit in the present invention), and the like. It is roughly structured.

  The base 15 is formed of, for example, synthetic resin, and an ink introduction needle 19 is attached to the upper surface of the base 15 with a filter 18 interposed as shown in FIG. The ink cartridge 7 is attached to the ink introduction needle 19 attached to the base 15.

  A circuit board 20 is attached to the other surface of the base 15 opposite to the surface to which the ink introduction needle 19 is attached. The circuit board 20 includes, for example, a drive circuit for controlling supply of a drive signal to a piezoelectric vibrator 29 (see FIG. 3) described later, a connector for connection to the printer body side, and a through hole for supplying ink. Etc. And this circuit board 20 is attached to the base 15 via the sheet | seat member 21 which functions as packing.

  The head case 16 is fixed to the base 15 and is a casing for housing a vibrator unit 22 having a piezoelectric vibrator 29 described later. For this reason, the housing case 32 (see FIG. 3) capable of housing the transducer unit 22 is formed in the head case 16. The vibrator unit 22 is inserted into the housing space 32 and fixed by bonding or the like. And the flow path unit 17 is being fixed to the front end surface on the opposite side to the attachment surface of the base 15 of the head case 16 with the adhesive agent.

  The flow path unit 17 is formed by joining and integrating with an adhesive or the like in a state where the elastic plate 23, the flow path forming substrate 24, and the nozzle plate 25 (corresponding to one kind of nozzle forming base member in the present invention) are laminated. Have been made.

  The nozzle plate 25 is a member made of, for example, a thin plate made of stainless steel, and fine nozzle openings 26 are formed in a row in the nozzle plate 25 at a pitch corresponding to the dot formation density of the printer 1.

  A head cover 27 is attached to the front end portion of the head case 16 so as to surround the periphery of the nozzle plate 25 from the outside. The head cover 27 is made of, for example, a metal thin plate member. The head cover 27 has a function of protecting the front end portions of the flow path unit 17 and the head case 16 and preventing the nozzle plate 25 from being charged.

  FIG. 3 is a cross-sectional view of the main part of the recording head 3. The vibrator unit 22 supplies a drive signal from the circuit board 20 to the piezoelectric vibrator group 30 as pressure generating means, a fixing plate 31 to which the piezoelectric vibrator group 30 is joined, and the piezoelectric vibrator group 30. For example, a flexible cable (not shown). The piezoelectric vibrator group 30 of the present embodiment includes a plurality of piezoelectric vibrators 29 (corresponding to a kind of pressure generating element in the present invention) arranged in a comb-teeth shape. Each piezoelectric vibrator 29 has a fixed end joined on the fixed plate 31, and a free end protruding outside the front end surface of the fixed plate 31. That is, each piezoelectric vibrator 29 is mounted on the fixed plate 31 in a so-called cantilever state. The fixing plate 31 that supports each piezoelectric vibrator 29 is made of, for example, stainless steel having a thickness of about 1 mm. In addition to the piezoelectric vibrator, an electrostatic actuator, a magnetostrictive element, or the like can be used as the pressure generating means.

  Inside the head case 16, an accommodation empty portion 32 that can accommodate the vibrator unit 22 is formed in a state where the height direction of the head case 16 is penetrated. The vibrator unit 22 is housed and fixed in the housing space 32 by bonding the back surface of the fixing plate 31 to the inner wall surface of the case that defines the housing space 32.

  A plurality of flow path forming substrates 24 correspond to the respective nozzle openings 26 in a state in which empty portions that become common ink chambers 33, groove portions that become ink supply ports 34, and empty portions that become pressure generation chambers 35 are partitioned by partition walls. It is a plate-shaped member formed side by side. The flow path forming substrate 24 is produced, for example, by etching a silicon wafer. Each of the pressure generating chambers 35 is formed as an elongated chamber in a direction perpendicular to the direction in which the nozzle openings 26 are arranged (nozzle row direction). The common ink chamber 33 communicates with an ink introduction path (not shown) provided in the ink introduction needle 19 via an ink communication path 37 formed through the height direction of the head case 16. This is a chamber into which ink stored in the ink cartridge 7 is introduced. The ink introduced into the common ink chamber 33 is supplied to each pressure generating chamber 35 through the ink supply port 34.

FIG. 4 is a cross-sectional view illustrating the configuration of the elastic plate.
The elastic plate 23 is a composite plate material obtained by laminating an elastically deformable film 41 made of a resin such as PPS (polyphenylene sulfide) on a metal thin plate 40 such as stainless steel, and the pressure generation chambers 35 arranged in a row are arranged. Seal in series.

  As shown in FIG. 4, the film 41 of the elastic plate 23 of the present embodiment has another film 41 b on the other surface of the metal thin plate 40 in addition to the film 41 a bonded to one surface of the metal thin plate 40. It is prepared in a joined state. Therefore, it has a three-layer structure in which the film 41a, the metal thin plate 40, and the film 41b are sequentially laminated. That is, the elastic plate 23 is formed by laminating the films 41 a and 41 b with both surfaces of the metal thin plate 40 sandwiched therebetween. The elastic plate 23 of the present invention may have a two-layer structure constituted by the thin metal plate 40 and one film 41a.

  Further, an island portion 43 is formed in a portion corresponding to the pressure generating chamber 35 of the elastic plate 23. The island portion 43 is formed in an island shape surrounded by a thin portion of only the film 41 by removing a part of the metal thin plate 40 in an annular shape by etching or the like. Specifically, the island portion 43 is formed in an elongated block shape in a direction orthogonal to the direction in which the nozzle openings 26 are arranged, similarly to the planar shape of the pressure generating chamber 35. In addition, the width of the island portions 43 in the arrangement direction (in the direction in which the nozzle openings 26 are arranged) is wider on the pressure generation chamber 35 side than the width on the nozzle opening 26 side (indicated by reference numeral W1 in FIG. 4). (Indicated by W2) is larger. The details of the method for producing the elastic plate 23 will be described later.

The tip of the free end portion of the piezoelectric vibrator 29 is joined to the island portion 43 thus configured via the film 41a, and this portion functions as a diaphragm portion.
Further, the elastic plate 23 seals one opening surface of the empty portion that becomes the common ink chamber 33, and also functions as a compliance portion. About the part which functions as this compliance part, only the elastic film 41a is made by etching.

  In the recording head 3, when the piezoelectric vibrator 29 is expanded and contracted in the element longitudinal direction, the island portion 43 moves in a direction close to or away from the pressure generation chamber 35. As a result, the volume of the pressure generating chamber 35 changes, and the pressure in the ink in the pressure generating chamber 35 varies. Due to this pressure fluctuation, ink droplets (a type of droplet) are ejected (jetted) from the nozzle opening 26.

Next, a method for producing the elastic plate 23 will be described. FIG. 5 is a cross-sectional view for explaining the production process of the elastic plate of the present invention.
First, when the metal thin plate 40 having the film 41a bonded to one surface with an adhesive or the like is etched, the etching proceeds not only in the thickness direction of the metal thin plate 40 but also in the plane direction as shown in FIG. Therefore, when viewed from the cross section, the metal thin plate 40 has a trapezoidal shape that gradually decreases in width as it moves away from the film 41a, and when viewed from the top surface (not shown), the surface not bonded to the film is present. The area is smaller than the bonded surface. In this manner, by removing a part of the metal thin plate 40 by etching or the like, the island part 43 is formed in an island shape. And the width | variety of the arrangement direction of this island part 43 is gradually small as it leaves | separates from the film 41a.

  Next, as shown in FIG. 5 (b), the film 41b is adhered to the surface of the etched metal thin plate 40 away from the film 41a, that is, the other surface of the metal thin plate 40 joined with the film 41a. Join. Finally, as shown in FIG. 5 (c), when the elastic plate 23 configured in this way is disposed in the flow path unit 17 in the direction in which the thickness direction (up and down) of the metal thin plate 40 is reversed, FIG. As shown, the elastic plate 23 in which the width in the arrangement direction of the island portions 43 is set larger than the width W1 on the nozzle opening 26 side is set to the flow path unit 17.

  As described above, in the recording head 3, the elastic plate 23 is configured by laminating the films 41 a and 41 b and the thin metal plate 40, and includes the island portion 43 formed on the thin metal plate 40 facing the pressure generating chamber 35. Since the width in the arrangement direction of the portion 43 is set larger than the width W1 on the piezoelectric vibrator 29 side than the width W1 on the nozzle opening 26 side, the width in the arrangement direction of the island portion 43 is set to the width W1 on the nozzle opening 26 side. As compared with the case where the width W2 on the piezoelectric vibrator 29 side is set to be smaller than that, the tolerance when joining the piezoelectric vibrator 29 to the island portion 43 can be widened. Therefore, the required position accuracy between the piezoelectric vibrator 29 and the island portion 43 can be relaxed, the yield can be improved, and the variation in the pressure in the pressure generating chamber 35 can be reduced by reducing the variation in the pressure fluctuation. Can be suppressed.

  Further, since the island portion 43 and the piezoelectric vibrator 29 are joined via the film 41b, the piezoelectric vibrator 29 side of the island portion 43 is protected by the film 41b, and the piezoelectric vibrator 29 is attached to the elastic plate 23. Even if the adhesive used for joining drips from between the joining surfaces, it is possible to prevent the adhesive from adhering to and sticking to the island portion 43. For this reason, it can prevent that an adhesive agent covers the outer periphery of the island part 43, and can suppress that the elasticity modulus of the elastic board 23 changes for every pressure generation chamber 35 which opposes the island part 43. FIG. Accordingly, variations in ink ejection performance can be suppressed.

  Further, since the films 41a and 41b sandwich both surfaces of the metal thin plate 40, the island portion 43 is accommodated between the films 41a and 41b, so that the island portion 43 can be protected. For this reason, each island portion 43 reliably transmits the pressure fluctuation caused by the piezoelectric vibrator 29 to the pressure generation chamber 35, so that variation in ink discharge performance for each pressure generation chamber 35 can be suppressed.

  The elastic plate 23 may be formed by etching the metal thin plate 40 having the film 41a bonded to one surface and then bonding the film 41b to the other surface. , 41b, the elastic plate 23 can be easily manufactured.

Next, another embodiment of the elastic plate will be described.
FIG. 6 is a cross-sectional view illustrating an elastic plate according to the second embodiment. The film 41b of the elastic plate 23 in the second embodiment is provided with a plurality of through holes 44 (corresponding to one kind of air opening holes in the present invention) penetrating in the thickness direction of the film 41b. That is, the space between the film 41 a and the film 41 b communicates with the space on the piezoelectric vibrator 29 side of the elastic plate 23. Therefore, the space between the films 41a and 41b can be in the same state as the atmosphere.

  As described above, in the elastic plate 23 of the second embodiment, the film 41b on the piezoelectric vibrator 29 side is provided with the air opening hole 44, so that the space between the films 41a and 41b and the outer space are provided. As a result, the volume of the space between the films does not depend on the surrounding temperature and atmospheric pressure, and the compliance in the pressure generating chamber 35 does not depend on the environment. .

By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.
For example, as in the second embodiment, the elastic plate 23 may not only provide the air opening hole 44 in the film 41b but also form the film 41b with a material that allows gas to pass through. That is, any form may be used as long as the space between the films 41a and 41b can be the same as the atmosphere. According to this elastic plate 23, since the film is formed of a material that allows gas to pass therethrough, the gas in the space between the films can be transmitted to the outer space, and the space between the film and the outer space Can keep the balance. As a result, the compliance in the pressure generating chamber becomes independent of the environment.

  In the above, the printer 1 which is a kind of liquid ejecting apparatus has been described as an example, but the present invention can also be applied to other liquid ejecting apparatuses. For example, a display manufacturing apparatus that manufactures color filters such as liquid crystal displays, an electrode manufacturing apparatus that forms electrodes such as organic EL (Electro Luminescence) displays and FEDs (surface emitting displays), and chips that manufacture biochips (biochemical elements) The present invention can also be applied to a manufacturing apparatus.

1 is a perspective view illustrating a configuration of a printer according to a first embodiment. FIG. 2 is an exploded perspective view illustrating a configuration of a recording head. 2 is a partial cross-sectional view illustrating an internal structure of a recording head. FIG. It is sectional drawing explaining the structure of an elastic board. It is sectional drawing explaining the preparation process of an elastic board, (a) is sectional drawing which shows the state which etched the metal thin plate, (b) is sectional drawing which shows the state which pinched | interposed the metal thin plate, (c) is ( It is sectional drawing which shows the state which reversed b). It is sectional drawing explaining the elastic board in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Recording head, 17 ... Channel unit, 22 ... Vibrator unit, 23 ... Elastic plate, 24 ... Channel formation substrate, 25 ... Nozzle plate, 26 ... Nozzle opening, 29 ... Piezoelectric vibrator, 35 ... Pressure generating chamber , 40 ... Metal thin plate, 41a, 41b (41) ... Film, 43 ... Island part, 44 ... Through hole, W1 ... Width on nozzle opening side, W2 ... Width on pressure generating element side

Claims (6)

A flow path forming substrate, comprising: a nozzle forming member in which a plurality of nozzle openings are arranged; a flow path forming substrate in which a pressure generating chamber corresponding to the nozzle openings is formed; and an elastic plate for sealing the pressure generating chamber. A flow path unit in which these are joined together,
An actuator unit that includes a pressure generating element that abuts on the elastic plate and applies pressure fluctuation to the pressure generating chamber;
A liquid ejecting head that ejects liquid droplets from a nozzle opening by operation of a pressure generating element,
The elastic plate is configured by laminating a film and a thin metal plate,
An island formed on a thin metal plate facing the pressure generating chamber;
The liquid ejecting head according to claim 1, wherein the width of the island portion in the arrangement direction is set larger on the pressure generating element side than on the nozzle opening side.   The liquid ejecting head according to claim 1, wherein the island part and the pressure generating element are joined via the film.   The liquid ejecting head according to claim 1, wherein the elastic plate is formed by laminating the film with both surfaces of the thin metal plate sandwiched therebetween.   4. The elastic plate according to claim 2, wherein the elastic plate is formed by etching a metal thin plate having a film bonded to one surface and then bonding the film to the other surface. Liquid jet head.   The liquid ejecting head according to claim 2, wherein the film on the pressure generating element side is provided with an air opening hole.   5. The liquid ejecting head according to claim 2, wherein the film on the pressure generating element side is formed of a material that transmits gas. 6.

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