JP2013158994A - Liquid jet head, method for producing liquid jet head, and liquid jet apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable liquid jet head in which the corrosiveness of a driving electrode is improved, and to provide a method for producing the same.SOLUTION: A liquid jet head 1 includes an actuator part 6 having a groove 3 sandwiched by side walls 2 and a driving electrode 9 formed on a wall surface 4 of the side wall 2. The surface of the driving electrode 9 is covered with a parylene film 14 having pinholes 16. The pinholes 16 in the parylene film 14 on the driving electrode 9 are filled with any metal selected from the group consisting of platinum, gold, silver, titanium, and palladium.

Description

  The present invention relates to a liquid ejecting head that ejects liquid from a nozzle to record characters and figures on a recording medium, or forms a functional thin film, a manufacturing method thereof, and a liquid ejecting apparatus.

  In recent years, an ink jet type liquid ejecting head has been used in which ink droplets are ejected onto recording paper or the like to record characters and figures, or a liquid material is ejected onto the surface of an element substrate to form a functional thin film. In this method, ink or liquid material is supplied from a liquid tank to a liquid ejecting head via a supply pipe, and ink or liquid material filled in the channel is discharged from a nozzle communicating with the channel. When discharging the liquid, the liquid ejecting head or the recording medium is moved to record characters and figures, or a functional thin film having a predetermined shape is formed.

  FIG. 7A is a cross-sectional view showing the configuration of this type of liquid jet head (FIG. 1 of Patent Document 1). The liquid ejecting head includes a ceramic plate 101 including a plurality of grooves 112 and a plurality of side walls 111 partitioning the grooves 112, and a cover plate 102 bonded via a bonding layer 103 so as to close the openings of the plurality of grooves 112. Consists of A metal electrode 113 is formed on the upper half of each side wall 111, and a protective film 120 is formed on the surface of the metal electrode 113. Each side wall 111 is made of a piezoelectric material that is polarized in the arrow direction 104.

  Each groove 112 constitutes an elongated ink flow path on the back side of the paper surface, and a nozzle plate (not shown) having an ink droplet ejection nozzle opened at a position corresponding to each groove 112 is bonded to the front side of the paper surface. Each groove 112 is filled with ink from a manifold (not shown). When a drive voltage is applied between the pair of metal electrodes 113d and 113e sandwiching the side wall 111 and an electric field is applied to the side wall 111b, the side wall 111b undergoes thickness-slip deformation so as to be bent. Utilizing the electrostrictive effect of this piezoelectric material, a drive voltage is applied between the metal electrodes 113e and 113f and the metal electrodes 113d and 113g to change the volume of the groove 112b, and pressure is applied to the ink filled in the groove 112b. Induces ink droplets from the nozzle. Actually, a high electric field is applied to the side walls 111b and 111c in the direction in which the volume of the groove 112b expands immediately before ink is ejected, and after the ink is sucked into the groove 112b, a low electric field is applied to reduce the volume of the groove 112b. Return to the original state and eject ink droplets from the nozzle.

Japanese Patent Laid-Open No. 06-246913

  In the liquid jet head of Patent Document 1, a protective film 120 is provided on the surface of the metal electrode 113. This is provided in order to insulate and protect the metal electrode 113 or to prevent corrosion of the electrode itself. As the protective film 120, silicon nitride (SiNx) and silicon oxynitride (SiON) are used. It is described that the film quality of silicon nitride or silicon oxynitride is improved to prevent the lower metal electrode 113 from being corroded by ink.

Specifically, the film thickness of silicon nitride or silicon oxynitride is 0.2 μm to a thickness that does not exceed 1/8 of the thickness of the sidewall 111, and the film density is 1.8 g / cm ³ or more. Furthermore, as shown in FIG. 7B, it is described that the metal electrode 113 and the stepped portion thereof are covered with a protective film 120. In addition, Cu decoration method is described as a film quality evaluation method. The Cu decoration method is a method in which a film is evaluated by dipping a sample in a copper plating solution as a film pinhole evaluation and counting the number of Cu precipitates resulting from the film pinhole.

  However, a CVD (Chemical Vapor Deposition) apparatus or a Plasma-CVD apparatus is required for film formation of silicon nitride or silicon oxynitride. In addition, a silicon nitride film or silicon oxynitride film formed by CVD or P-CVD requires a patterning process by photolithography and etching after film formation, which increases the number of manufacturing steps and requires large manufacturing equipment. It becomes. Also, even if the above silicon nitride or silicon oxynitride is used, pinholes cannot be completely removed, and increasing the film thickness to completely remove pinholes increases the internal stress of the film, It affects the thickness-slip deformation of the side wall 111, or cracks are generated in the film and it becomes easy to peel off. Further, although the Cu decoration method is used for evaluating the film quality, since Cu has a corrosive property to ink, it cannot be left in the groove 112 as a material in contact with the ink.

  The present invention has been made in view of the above problems, and has been made for the purpose of improving the corrosivity of the drive electrode and providing a highly reliable liquid ejecting apparatus.

  The liquid jet head of the present invention includes an actuator unit having a groove sandwiched between side walls and a drive electrode formed on the wall surface of the side wall, and the drive electrode is covered with a parylene film having a pinhole. The pinhole of the parylene film on the drive electrode is filled with any metal of platinum, gold, silver, titanium or palladium.

  The liquid ejecting apparatus according to the aspect of the invention includes the liquid ejecting head, a moving mechanism that reciprocates the liquid ejecting head, a liquid supply pipe that supplies the liquid to the liquid ejecting head, and the liquid that is supplied to the liquid supply pipe. And a liquid tank.

  The method of manufacturing a liquid jet head according to the present invention includes a groove forming step of forming a groove on the actuator substrate, a conductive film forming step of forming a conductive film on the actuator substrate, and patterning the conductive film to form the groove. An electrode forming step of forming a drive electrode on a side surface of the wall; a cover plate bonding step of forming a laminate by bonding a cover plate to the actuator substrate so as to cover the groove; and an insulating film on the surface of the drive electrode. An insulating film forming step to form, a plating treatment step of plating the laminated body to fill a pin hole formed in the insulating film on the drive electrode with a metal, and a nozzle plate on the end face of the laminated body And a nozzle plate bonding step for bonding.

  Further, an insulating film removing step of removing the insulating film from the end face of the actuator substrate is included before the nozzle plate bonding step.

  The electrode forming step includes a step of forming an electrode terminal that is electrically connected to the drive electrode on the surface of the actuator substrate.

  The insulating film forming step is a step of forming a parylene film on the surface of the drive electrode.

  The cover plate joining step includes a step of cutting and dividing the laminate.

  The metal is platinum, gold, silver, titanium, or palladium.

  The liquid ejecting head of the present invention includes an actuator unit having a groove sandwiched between side walls and a drive electrode formed on the wall surface of the side wall, and the drive electrode is covered with a parylene film having a pinhole, The pinhole of the parylene film on the electrode is filled with a metal of platinum, gold, silver, titanium, or palladium. Accordingly, the drive electrode does not come into contact with the liquid, and the pinhole of the parylene film is filled with the corrosion-resistant metal. Therefore, the drive electrode is not corroded, and a highly reliable liquid jet head can be provided. .

FIG. 3 is a schematic cross-sectional view of the liquid jet head according to the first embodiment of the present invention. FIG. 3 is a schematic exploded perspective view of the liquid jet head according to the first embodiment of the present invention. FIG. 10 is a process diagram illustrating a basic manufacturing method of a liquid jet head according to a second embodiment of the invention. FIG. 10 is a diagram for explaining each step of the method of manufacturing the liquid jet head according to the second embodiment of the present invention. FIG. 10 is a diagram for explaining each step of the method of manufacturing the liquid jet head according to the second embodiment of the present invention. FIG. 6 is a schematic perspective view of a liquid ejecting apparatus according to a third embodiment of the invention. It is sectional drawing which shows the structure of a conventionally well-known liquid ejecting head.

(First embodiment)
1 and 2 are diagrams for explaining a liquid jet head 1 according to a first embodiment of the present invention. 1A is a schematic cross-sectional view in the channel direction, FIG. 1B is a schematic cross-sectional view in the direction orthogonal to the channel, and FIG. 2 is a schematic exploded perspective view of the liquid ejecting head 1.

  The liquid ejecting head 1 includes an actuator unit 6 including an actuator substrate 7 having a plurality of grooves 3 formed on a surface thereof, a cover plate 8 including a liquid supply chamber 13, and a plurality of nozzles 17. The nozzle plate 12 is bonded to one end of the nozzle plate 12.

  This will be specifically described. The actuator unit 6 includes an actuator substrate 7 in which a groove 3 sandwiched between two side walls 2 is formed, a cover plate 8 joined to an upper end surface of the side wall 2 so as to cover an upper opening of the groove 3, and a wall surface of the side wall 2 4 and the drive electrode 9 formed in 4. The upper end opening of the groove 3 is closed by the cover plate 8 to form a channel 5. Each side wall 2 is made of a piezoelectric material and is polarized in the z direction. A plurality of nozzles 17 are formed on the nozzle plate 12, and each nozzle 17 communicates with each of the plurality of channels 5 that open at one end of the actuator unit 6. The surface of the actuator substrate 7 is exposed at the end opposite to the one end surface of the actuator 6, and the terminal electrode 10 is installed on the exposed surface. The terminal electrode 10 is electrically connected to the drive electrode 9.

The liquid supplied to the liquid supply chamber 13 is supplied to the plurality of channels 5, and each channel is filled with the liquid. When a drive signal is applied to the terminal electrode 10, the side wall 2 is deformed in thickness and changes the volume of the channel 5 according to the drive signal. As a result, the liquid filling the channel 5 is discharged from the nozzle 17.

  Here, the drive electrode 9 is covered with a parylene film 14, and a pinhole 16 is formed in the parylene film 14. The pinhole 16 of the parylene film 14 on the drive electrode 9 is buried with the metal 11. As the metal 11, platinum, gold, silver, titanium, or palladium is used. Therefore, even if the channel 5 is filled with a highly corrosive liquid, the drive electrode 9 and the liquid do not come into contact with each other, and the metal 11 filling the pinhole 16 has corrosion resistance, so the drive electrode 9 does not corrode and is reliable. Improves. As will be described later, the metal 11 of the pinhole 16 is formed by electroplating.

  Note that a corrosive conductive film such as an aluminum film or a nickel film can be used as the drive electrode 9. The parylene film 14 can have a thickness of 1 μm to 5 μm, preferably 2 μm to 3 μm. The depth of the groove 3 can be 300 μm to 500 μm, and the thickness of the side wall 2 can be 40 μm to 100 μm. PZT ceramics can be used as the actuator substrate 7 and the cover plate 8.

  Further, the liquid jet head 1 according to the present invention is not limited to the one shown in FIG. In short, the groove 3 is sandwiched between the side walls 2, the drive electrode 9 is formed on the wall surface of the side wall 2, and the surface of the drive electrode 9 is covered with the parylene film 14 having the pinhole 16. The pinhole 16 of the parylene film 14 is filled with a metal 11 of platinum, gold, silver, titanium, or palladium.

(Second embodiment)
3 to 5 are views for explaining a method of manufacturing the liquid jet head 1 according to the second embodiment of the invention. FIG. 3 is a process diagram showing a basic manufacturing method of the liquid jet head 1 of the present invention, and FIGS. 4 and 5 are diagrams for explaining each process. The same portions or portions having the same function are denoted by the same reference numerals.

  First, as shown in FIG. 4A, an actuator substrate 7 made of PZT (lead zirconate titanate) ceramics, which is polarized in the direction perpendicular to the substrate surface, is prepared. Next, a photosensitive resin film 21 is attached to the surface of the actuator substrate 7 and a pattern is formed through a photo process. A region where the photosensitive resin film 21 is removed is a region where an electrode is formed, and a region where the photosensitive resin film 21 is left is a region where an electrode is removed.

  Next, in the groove forming step S1, as shown in FIG. 4B, the dicing blade 22 is lowered to the surface of the actuator substrate 7 and moved to form a large number of parallel grooves 3. FIG. 4B is a view seen from a direction orthogonal to the direction of the groove 3, and a lower view is seen from the direction of the groove 3. The depth of the groove 3 is 300 μm to 400 μm, and the thickness of the side wall 2 separating the groove 3 is 40 μm to 100 μm.

  Next, in the conductive film forming step S2, a conductive film 23 is formed on the actuator substrate 7 as shown in FIG. For example, aluminum is deposited on the wall surface 4 of the side wall 2 and the surface of the actuator substrate 7 by an oblique evaporation method to form the conductive film 23. As shown in the upper part of FIG. 4C, the groove 3 of the actuator substrate 7 is directed downward, and a conductive material is deposited by an oblique evaporation method from an angle −θ and an angle + θ with respect to the normal line of the lower surface. Thus, the conductive film 23 is formed from the upper surface of the photosensitive resin film 21 of the actuator substrate 7 and the upper end of the wall surface 4 to a depth of approximately ½.

  Next, in the electrode formation step S3, as shown in FIG. 4D, the conductive film 23 is patterned to form the drive electrode 9 on the wall surface 4. At the same time, the terminal electrode 10 (not shown) and the wiring for connecting the terminal electrode 10 and the drive electrode 9 are formed. In this embodiment, the photosensitive resin film 21 is removed and the conductive film 23 is patterned by a lift-off method. A region where the conductive film 23 remains when the photosensitive resin film 21 is removed is a conduction between the drive electrode 9 on the wall surface 4 and the terminal electrode 10 (not shown) on the end surface of the actuator substrate 7, and the drive electrode 9 and the terminal electrode 10. The wiring is not shown.

  Next, in the cover plate joining step S4, as shown in FIG. 4E, the cover plate 8 is joined to the actuator substrate 7 so as to cover the groove 3, thereby forming the actuator portion 6 as a laminate. A liquid supply chamber 13 is formed in the cover plate 8 in advance. Bonding uses an adhesive. In order to avoid cracking and warping due to a difference in thermal expansion coefficient, it is preferable to use the same material as the actuator substrate 7 as the cover plate 8. When manufacturing a large number of liquid ejecting heads 1, the stacked body is cut and divided into individual actuator portions 6. Thereby, an insulating film can be formed on the surface of the drive electrode 9 in the next insulating film forming step S5.

  Next, in an insulating film formation step S5, an insulating film 18 is formed on the surface of the drive electrode 9, as shown in FIG. A parylene film can be formed as the insulating film 18. A laminate composed of the actuator unit 6 is put into a vacuum chamber, a parylene raw material, for example, diparaxylylene is vaporized in a sublimation furnace, paraxylylene radicals are generated in a pyrolysis furnace, and the actuator unit 6 is vapor-phase polymerized to obtain a high molecular weight A polyparaxylylene (parylene) film is formed. The thickness of the parylene film is 1 μm to 5 μm, preferably 2 μm to 3 μm. Since paraxylylene radicals are introduced into the laminated body put in a vacuum, the paraxylene radicals enter the grooves 3 and undergo vapor phase polymerization on the surface of the wall surface 4 including the drive electrodes 9. FIG. 5F also shows the pinhole 16 formed in the insulating film 18. The pinhole 16 is generated due to dust during film formation, surface irregularities, and the like.

  Next, when the parylene film 14 is formed as the insulating film 18, the parylene film 14 is removed from the end face of the actuator unit 6 on the nozzle plate 12 side and the upper surface of the terminal electrode 10 (insulating film removing step). The parylene film 14 can be removed from the outer surface of the actuator unit 6 by an ashing process using oxygen plasma.

  Next, in the plating process S6, as shown in FIG. 5G, the actuator portion 6 is plated to fill the pinholes of the insulating film 18 on the drive electrodes 9 with metal. The metal is platinum, gold, silver, titanium, or palladium. Electroplating is performed by connecting the terminal electrode 10 of the actuator unit 6 to the cathode and connecting the metal to be filled to the anode. Thereby, the exposed surface of the drive electrode 9 can be covered with a corrosion-resistant metal.

  Next, in the nozzle plate bonding step S7, as shown in FIG. 4 (h), the nozzle plate 12 is bonded to the end surface of the actuator section 6 that is a laminate. A nozzle 17 communicating with the channel 5 of the actuator unit 6 may be formed in the nozzle plate 12 in advance, or the nozzle 17 may be opened after bonding. A polyimide film can be used as the nozzle plate 12.

  As described above, the drive electrode 9 does not come into contact with the liquid, and the pinhole 16 of the insulating film 18 is filled with the corrosion-resistant metal 11, so that the liquid jet head 1 with high reliability can be manufactured. Note that the method for manufacturing a liquid jet head according to the present invention is not limited to using a parylene film as the insulating film 18, and a silicon nitride film, a silicon oxide film, or other insulating films can be used. For example, after the electrode forming step S3, the terminal electrode 10 is covered with the insulating film 18 in the insulating film forming step S5, then the cover plate 8 is bonded to the actuator substrate 7 in the cover plate bonding step S4, and then the plating processing step S6. Thus, the pinhole 16 of the insulating film 18 can be filled with a metal having high corrosion resistance.

(Third embodiment)
FIG. 6 is a schematic perspective view of the liquid ejecting apparatus 30 according to the third embodiment of the present invention. The liquid ejecting apparatus 30 includes a moving mechanism 40 that reciprocates the liquid ejecting heads 1 and 1 ′, flow path portions 35 and 35 ′ that supply liquid to the liquid ejecting heads 1 and 1 ′, and flow path portions 35 and 35 ′. Liquid pumps 33 and 33 'for supplying liquid to the liquid tanks and liquid tanks 34 and 34'. Each liquid ejecting head 1, 1 ′ includes a plurality of ejection grooves, and ejects droplets from nozzles communicating with the ejection grooves. The liquid ejecting heads 1 and 1 ′ are the same as those described in the first embodiment.

  The liquid ejecting apparatus 30 includes a pair of conveying units 41 and 42 that convey a recording medium 44 such as paper in the main scanning direction, liquid ejecting heads 1 and 1 ′ that eject liquid onto the recording medium 44, and a liquid ejecting head. 1, 1 ′ carriage unit 43, liquid tanks 34, 34 ′ and liquid pumps 33, 33 ′ that supply the liquid stored in the liquid tanks 34, 34 ′ to the flow path portions 35, 35 ′, the liquid jet head 1, And a moving mechanism 40 that scans 1 ′ in the sub-scanning direction orthogonal to the main scanning direction. A control unit (not shown) controls and drives the liquid ejecting heads 1, 1 ′, the moving mechanism 40, and the conveying units 41 and 42.

  The pair of conveying means 41 and 42 includes a grid roller and a pinch roller that extend in the sub-scanning direction and rotate while contacting the roller surface. A grid roller and a pinch roller are moved around the axis by a motor (not shown), and the recording medium 44 sandwiched between the rollers is conveyed in the main scanning direction. The moving mechanism 40 couples a pair of guide rails 36 and 37 extending in the sub-scanning direction, a carriage unit 43 slidable along the pair of guide rails 36 and 37, and the carriage unit 43 to move in the sub-scanning direction. An endless belt 38 is provided, and a motor 39 that rotates the endless belt 38 via a pulley (not shown) is provided.

  The carriage unit 43 mounts a plurality of liquid jet heads 1, 1 ′, and ejects, for example, four types of liquid droplets of yellow, magenta, cyan, and black. The liquid tanks 34 and 34 'store liquids of corresponding colors and supply them to the liquid jet heads 1 and 1' via the liquid pumps 33 and 33 'and the flow path portions 35 and 35'. Each liquid ejecting head 1, 1 ′ ejects droplets of each color according to the drive signal. An arbitrary pattern is recorded on the recording medium 44 by controlling the timing at which liquid is ejected from the liquid ejecting heads 1, 1 ′, the rotation of the motor 39 that drives the carriage unit 43, and the conveyance speed of the recording medium 44. I can.

DESCRIPTION OF SYMBOLS 1 Liquid ejecting head 2 Side wall 3 Groove 4 Wall surface 5 Channel 6 Actuator part 7 Actuator board 8 Cover plate 9 Drive electrode 10 Terminal electrode 11 Metal 12 Nozzle plate 13 Liquid supply chamber 14 Parylene film 16 Pinhole 17 Nozzle 18 Insulating film

Claims (8)

An actuator unit having a groove sandwiched between side walls and a drive electrode formed on the wall surface of the side wall;
The drive electrode has a surface covered with a parylene film having pinholes, and the pinhole of the parylene film on the drive electrode is filled with a metal of platinum, gold, silver, titanium, or palladium. Jet head. A liquid ejecting head according to claim 1;
A moving mechanism for reciprocating the liquid jet head;
A liquid supply pipe for supplying a liquid to the liquid ejecting head;
And a liquid tank that supplies the liquid to the liquid supply pipe. A groove forming step of forming grooves on the actuator substrate;
A conductive film forming step of forming a conductive film on the actuator substrate;
An electrode forming step of patterning the conductive film to form a drive electrode on a side surface of the wall constituting the groove;
A cover plate joining step of joining a cover plate so as to cover the groove on the actuator substrate to form a laminate;
An insulating film forming step of forming an insulating film on the surface of the drive electrode;
A plating treatment step of filling the pinholes formed in the insulating film on the drive electrodes with a metal by plating the laminated body; and
A nozzle plate bonding step of bonding a nozzle plate to an end face of the laminate.   The method of manufacturing a liquid jet head according to claim 3, further comprising an insulating film removing step of removing the insulating film from an end surface of the actuator substrate before the nozzle plate bonding step.   5. The method of manufacturing a liquid jet head according to claim 3, wherein the electrode forming step includes a step of forming an electrode terminal that is electrically connected to the drive electrode on a surface of the actuator substrate.   The method of manufacturing a liquid jet head according to claim 3, wherein the insulating film forming step is a step of forming a parylene film on a surface of the drive electrode.   The method of manufacturing a liquid jet head according to claim 3, wherein the cover plate joining step includes a step of cutting and dividing the stacked body.   The method for manufacturing a liquid jet head according to claim 3, wherein the metal is any one of platinum, gold, silver, titanium, or palladium.

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