JP2010069855A - Method of manufacturing inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an inkjet head excelling in reliability by reducing metal residues in mutual insulating sections of electrodes to prevent an electric short circuit between the electrodes. <P>SOLUTION: The surface of a substrate 1 is etched, and the surface of the substrate 1 is provided with piezoelectric members 15, 13. A metal film 22 is formed on the surfaces of the piezoelectric members 15, 13 and substrate 1, and laser patterning processing is applied to the metal film 22 to form a plurality of electrodes P2. Prior to forming the metal film 22, the forming predetermined portions of the respective electrodes P2 on the etched surface of the substrate 1 is smoothed beforehand by irradiation of laser beams. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an inkjet head used in a printer or the like.

As a method of manufacturing a liquid ejection device, so-called an inkjet head, used in an inkjet printer or the like, a plurality of rows of ink channels are formed in parallel on a substrate, and then a thin plating thin layer is formed on the surface of the substrate by electroless plating. The thin plating thin layer is selectively removed by irradiating the thin plating thin layer with a laser beam, and the remaining portion of the thin plating thin layer is made into a plurality of electrodes, and then further electroless until a predetermined thickness is obtained on the surface of the substrate. A plating method is generally used (for example, Patent Document 1).
JP 2002-129348 A

  In the electroless plating method, in order to obtain a predetermined adhesion between the surface of the substrate and the plating film, it is necessary to roughen the surface of the substrate by an etching process. However, the surface roughened by the etching process has a mesh shape, and there are some places where deep unevenness occurs locally. When electroless plating is performed in this state, a metal film that enters the thickness direction of the substrate is deposited.

  For this reason, even if a plurality of electrodes are formed by laser patterning treatment that irradiates a metal film with laser light, metal residues are generated in the insulating portions between the electrodes, and the metal residues cause electrical contact between the electrodes. Will cause a short circuit.

  Although it is conceivable to remove the deposited metal film with a high-power laser beam, doing so may damage the substrate or each electrode formed by laser patterning, which is not a preferable method.

  The present invention takes the above-mentioned circumstances into consideration, and the object thereof is to reduce metal residues in the insulating portions between the electrodes, thereby preventing electrical shorts between the electrodes. It is an object of the present invention to provide a method for manufacturing an ink jet head that is excellent in reliability.

  According to a first aspect of the present invention, there is provided an ink jet head manufacturing method comprising: etching a surface of a substrate; providing a piezoelectric member on the surface of the substrate; forming a metal film on the surface of the piezoelectric member and the substrate; A plurality of electrodes are formed by a laser patterning process, and before the metal film is formed, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser irradiation.

  According to the method for manufacturing an ink jet head of the present invention, it is possible to reduce metal residues in the insulating portions between the electrodes. Thereby, an electrical short circuit between the electrodes can be prevented, and the reliability is improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a shear wall type side shooter type will be described as an example of an inkjet head according to the present invention.

  The principle of ink ejection of this ink-jet head is that two plate-like piezoelectric members polarized in the plate thickness direction are bonded together with an adhesive so that the polarization directions are opposite to each other, and the two piezoelectric members A plurality of grooves are formed at predetermined intervals, electrodes are formed in the respective pressure chambers using these grooves as pressure chambers, and a drive voltage is applied to these electrodes, whereby columnar portions ( Each piezoelectric member) is deformed to apply pressure for ink ejection to each pressure chamber, and ink droplets are ejected from nozzles communicating with each pressure chamber.

  That is, as shown in FIG. 1, an actuator row A and an actuator row B are formed on the surface of a plate-like substrate (also referred to as a base substrate) 1 made of alumina which is a low dielectric constant member. A frame member 2 is mounted in a state surrounding the actuator row B, and a nozzle plate (also referred to as an orifice plate) 3 is provided on the frame member 2. The nozzle plate 3 is formed of a rectangular polyimide film and has a pair of nozzle rows 4. Each of these nozzle rows 4 is formed by an array of a plurality of nozzles 5.

  The actuator rows A and B are formed by, for example, attaching two piezoelectric members made of PZT (lead zirconate titanate) vertically in a trapezoidal shape so that their polarization directions face each other. Each has a plurality of pressure chambers 6 arranged along each of which the surface is cut and formed into a groove shape. These pressure chambers 6 are in positions corresponding to the respective nozzles 5 of the nozzle plate 3, and each columnar portion is deformed by applying a voltage to the columnar portions (both piezoelectric members) between the pressure chambers 6. Due to the deformation, pressure for ink ejection is applied to each pressure chamber 6, and ink is ejected from each nozzle 5.

  Electrodes for applying a voltage to the columnar portions (piezoelectric members) between the pressure chambers 6 are formed on the pressure chambers 6 and the substrate 1. These electrodes are formed on the substrate by electroless nickel plating and electric field gold plating. A metal film is formed on the surface of 1, and the metal film is formed on the remaining portion of the metal film by a process (so-called subtracting method) in which the metal film is burned off by laser light and removed.

  In the substrate 1, a plurality of circular ink inlets 7 are arranged between the actuator rows A and B, and a plurality of ink outlets 8 are arranged at positions sandwiching the actuator rows A and B from both sides. Yes.

  The flow of the manufacturing process of this inkjet head is shown in FIG. 2, and the transition of the manufacturing process is shown in FIGS.

  First, as shown in FIG. 3, a substrate 1 having an ink inlet 7 and an ink outlet 8 is formed by mold molding or machining of alumina. A metal film is formed on the surface of the substrate 1 by electroless plating to form electrodes. In order to obtain a predetermined adhesion between the substrate 1 and the metal film at that time, as shown in FIG. Further, a surface treatment 11 is performed on the surface of the substrate 1. Since the adhesiveness in the case of electroless plating is mechanically obtained by the anchor effect, sandblasting, chemical etching, mechanical polishing treatment, etc. can be considered as a method of the surface treatment 11, but a predetermined adhesiveness is obtained. For this, chemical etching is suitable. Specifically, the substrate 1 is immersed in phosphoric acid heated to 200 ° C. for a predetermined time, and the surface of the substrate 1 is chemically etched.

  Next, the process which adhere | attaches and processes a piezoelectric member is performed with respect to the surface of the board | substrate 1 in which the surface treatment 11 by the etching was performed. FIG. 5 shows this processing state viewed from above, and FIG. 6 shows a cross section taken along the line XX of FIG. 5 in the direction of the arrow. That is, the plate-like piezoelectric members 15 and 13 made of PZT are bonded to each other with the adhesive 14 so that the polarization directions are opposite to each other, and the piezoelectric members 15 and 13 are cut into strips to form the adhesive 12. Thus, bonding is performed so that bubbles do not remain on the surface of the substrate 1. The adhesives 14 and 12 are epoxy adhesives and are cured by heat curing. The condition is 2 hours at 120 ° C. Furthermore, the piezoelectric members 15 and 13 are cut into a predetermined trapezoidal shape by machining.

  Subsequently, as shown in FIG. 7, the piezoelectric members 15 and 13 are cut into a trapezoidal shape, and the two rows of the piezoelectric members 15 and 13 are cut along the longitudinal direction by cutting using a diamond wheel for machining. In addition, a plurality of grooves, that is, pressure chambers 6 are sequentially formed in a state shifted by a half pitch for each row. The portions that become the wall surfaces of these pressure chambers 6 are indicated by reference numerals 15a, 14a, 13a and dots. Each pressure chamber 6 has a depth of 300 μm, a width of 80 μm, and an effective ink channel length of 2 mm.

  Preprocessing for electrode formation is performed on the two rows of piezoelectric members 15 and 13 formed in this way. FIG. 8 shows the state of this pre-processing from above, and FIG. 9 shows a cross section along the YY line in FIG. 8 in the direction of the arrow. In order to form electrodes, a metal film is formed by electroless plating, and electrode separation and removal (laser patterning process) is performed to remove unnecessary portions of the metal film by irradiating the metal film with laser light. As a previous step, the formation site of each electrode on the surface of the substrate 1 is smoothed in advance by laser light irradiation to prevent the metal film from being deposited in the depth direction of the substrate 1 in advance. A portion to be irradiated with the laser light is surrounded by a two-dot chain line circle.

  The portion irradiated with the laser beam changes from a roughened state by etching to a smooth state because alumina, which is the material of the substrate 1, is thermally melted.

  In this laser light irradiation, for example, a scanning method is employed in which YVO4 laser light having a wavelength of 532 nm, an output of 1.5 W, and a spot diameter of 30 μm is irradiated toward the substrate 1 by a galvano scanner.

  Next, as shown in FIG. 10, a metal film 22 that forms the basis of each electrode is formed on the entire surface of the substrate 1 by electroless plating. As a method for forming the metal film 22, there are a sputtering method, a CVD method, a plating method, and the like. As a method for reliably forming the metal film 22 up to the inside of the groove (pressure chamber 6), an electroless plating method is selected. Yes. Specifically, Pd (palladium) serving as a catalyst nucleus is applied to the substrate 1 as a pretreatment for plating by a sensitizing-activation method, and further immersed in an electroless nickel plating solution to form a nickel plating film 21. The nickel plating film 21 has a laminated structure of Bi-B having high conductivity and Ni-P film having high corrosion resistance. Alternatively, a single film of Ni—B or Ni—P may be used. The nickel plating film 21 has a thickness of 0.6 to 1 μm, and the metal film 22 has a thickness of 0.1 μm.

  Subsequently, a laser patterning process for actually forming each electrode is performed on the surface of the substrate 1 on which the nickel plating film 21 and the metal film 22 are formed. FIG. 11 shows this processing state viewed from above, and FIG. 12 shows a cross section taken along the line ZZ in FIG. 11 in the arrow direction. That is, the remaining portions obtained by removing unnecessary portions of the nickel plating film 21 and the metal film 22 by laser light irradiation become the electrodes P1 in the pressure chambers 6 in the two rows of piezoelectric members 15 and 13, and the substrate 1 It becomes each electrode P2 in the surface. In this case, a laser beam equivalent to a laser beam obtained by thermally melting the alumina portion is used. The laser output is 1.8W.

  FIGS. 13 and 14 show a state where the electrodes P1 and P2 are formed on the substrate 1 and a state where the nozzle plate 3 is mounted via the frame member 2. FIG. FIG. 13 is a view of a state in which a part of the nozzle plate 3 is missing as viewed from above, and FIG. 14 is a view of a cross section similar to the ZZ line of FIG. An ink chamber 24 is secured inside the frame member 2.

  Here, FIG. 15 shows a flow of a conventional method for manufacturing an inkjet head as a reference. Comparing this conventional manufacturing method with this embodiment, the step of forming the substrate 1 in FIG. 3, the step of performing the surface treatment 11 by etching in FIG. 4, and the two rows of piezoelectric members 15 and 13 in FIGS. The process of forming, the process of forming the groove (pressure chamber 6) in FIG. 7, the process of forming the nickel plating film 21 and the metal film 22 in FIG. 10, and the process of the laser patterning process in FIGS. .

This embodiment is different from the prior art in that it has the pre-processing shown in FIGS.
If there is no pretreatment of FIGS. 8 and 9, there is a possibility that a metal residue remains in the insulating portion between the electrodes P2 and an electrical short circuit occurs between the electrodes P2. As can be seen from the experimental results of FIG. 16 in which the film thickness of the etched portion and the film thickness of the nickel plating film deposited on the laser irradiation surface are compared, the film thickness of the etched portion is greater than the film thickness of the nickel plating film. The reason is that the thickness is about 0.4 to 0.5 μm. That is, as a result of roughening the surface of the substrate 1 by etching so as to maintain the adhesion between the nickel plating film 21 and the substrate 1, unevenness is generated in the thickness direction of the substrate 1. This is because the nickel plating film 21 is deposited. Even if this deposited nickel plating film 21 is subjected to laser patterning to form each electrode P2, a metal residue 21x is generated in an insulating portion between the electrodes P2, and the metal residue 21x causes a gap between the electrodes P2. Cause an electrical short circuit.

  On the other hand, in the present embodiment, the pre-processes of FIGS. 8 and 9 change the formation planned site of each electrode P2 on the surface of the substrate 1 from a state roughened by etching by laser irradiation in advance to a smooth state. Therefore, when the electrodes P2 are formed, the metal residue 21x generated in the insulating portion between the electrodes P2 can be reduced.

  Since the metal residue 21x can be reduced, an electrical short circuit between the electrodes P2 can be prevented, and an operation with high reliability as an ink jet head is always possible.

  In addition, this invention is not limited to said each embodiment, A various deformation | transformation implementation is possible in the range which does not change a summary.

1 is a perspective view showing an appearance of an inkjet head according to the present invention. The figure which shows the flow of the manufacturing process of one Embodiment. The figure for demonstrating the formation process of the board | substrate in one Embodiment. The figure for demonstrating the process of the surface treatment by the etching in one Embodiment. The figure for demonstrating the formation process of the trapezoidal piezoelectric member of 2 rows in one Embodiment. The figure which looked at the cross section in alignment with the XX of FIG. 5 in the arrow direction. The figure for demonstrating the formation process of the groove | channel in one Embodiment. The figure for demonstrating the process of the pre-processing in one Embodiment. The figure which looked at the cross section in alignment with the YY line of FIG. 8 in the arrow direction. The figure for demonstrating the formation process of the nickel plating film and metal film in one Embodiment. The figure for demonstrating the process of the laser patterning process in one Embodiment. The figure which looked at the cross section in alignment with the ZZ line of FIG. 11 in the arrow direction. The figure which shows the state in which each electrode and each conductive pattern in one Embodiment were formed, and the state in which the nozzle plate 3 was mounted | worn. The figure which looked at the same line cross section as the said ZZ line of FIG. The figure which shows the flow of the conventional manufacturing method as reference. The figure which shows the result of having confirmed by experiment the film thickness of the etching part, and the film thickness of the nickel plating film | membrane deposited on the laser irradiation surface for comparison with one Embodiment and the conventional manufacturing method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Frame member, 3 ... Nozzle plate, 4 ... Nozzle row, 5 ... Nozzle, 6 ... Pressure chamber, 7 ... Ink inlet, 8 ... Ink outlet, 11 ... Surface treatment by etching, 12, 14 ... Adhesive, 13, 15 ... Piezoelectric member, 13a, 14a, 15a ... Wall surface of groove, 21 ... Nickel plating film, 22 ... Metal film, P1 ... Electrode, P2 ... Conductive pattern

Claims (6)

An inkjet head that etches the surface of a substrate, provides a piezoelectric member on the surface of the substrate, forms a metal film on the surface of the piezoelectric member and the substrate, and forms a plurality of electrodes by laser patterning treatment on the metal film. In the manufacturing method,
A method of manufacturing an ink jet head, characterized in that, prior to the formation of the metal film, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser irradiation. The surface of the substrate is etched, a piezoelectric member is provided on the surface of the substrate, a metal film is formed on the surface of the piezoelectric member and the substrate by an electroless plating method, and the piezoelectric member and In the method of manufacturing an ink jet head for forming a plurality of electrodes on the substrate,
A method of manufacturing an ink jet head, characterized in that, prior to the formation of the metal film, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser light irradiation. The surface of the substrate is etched, a piezoelectric member is provided on the surface of the substrate, a metal film is formed on the surface of the piezoelectric member and the substrate by an electroless plating method, and the piezoelectric member and In the method of manufacturing an ink jet head for forming a plurality of electrodes on the substrate,
A method of manufacturing an ink jet head, characterized in that, prior to the formation of the metal film, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser light irradiation. The surface of the substrate is etched, a piezoelectric member is provided on the surface of the substrate, a plurality of grooves are formed in the piezoelectric member, and a metal film is formed on the grooves and the surface of the substrate by an electroless plating method. In the method of manufacturing an inkjet head, a plurality of electrodes are formed in each groove and on the substrate by a laser patterning process for:
A method of manufacturing an ink jet head, characterized in that, prior to the formation of the metal film, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser light irradiation. The surface of the substrate is etched, a piezoelectric member is provided on the surface of the substrate, a plurality of grooves are formed in the piezoelectric member, and a metal film is formed on the grooves and the surface of the substrate by an electroless plating method. In the method of manufacturing an inkjet head, an unnecessary portion of the metal film is removed by irradiating a laser beam to form a plurality of electrodes in each groove and on the substrate.
A method of manufacturing an ink jet head, characterized in that, prior to the formation of the metal film, portions where the electrodes are to be formed on the surface of the etched substrate are smoothed in advance by laser light irradiation.   6. The method of manufacturing an ink jet head according to claim 1, wherein the etching roughens the surface of the substrate.

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