JP3120341B2 - Method of manufacturing inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ink jet head for generating recording droplets used in an ink jet recording system.

[0002]

2. Description of the Related Art An ink jet head applied to an ink jet recording system generally includes an ink discharge port (orifice), an ink passage, and an ink discharge pressure generating section provided in a part of the ink passage.

Conventionally, as a method for producing such an ink-jet head, for example, a fine groove is formed on a glass or metal plate by cutting or etching, and then the plate on which the groove is formed is replaced with another appropriate plate. There is known a method of forming an ink passage by bonding with an ink. However, in the head manufactured by the conventional method, the roughness of the inner wall surface of the ink passage to be cut is too large, and the ink passage is distorted due to a difference in etching rate, so that it is difficult to obtain an accurate ink passage. In addition, the ink ejection characteristics of the formed inkjet head are likely to vary. In addition, there is a disadvantage that the plate is easily chipped or cracked during the cutting process, and the production yield is poor. When the etching process is performed, there are many manufacturing steps, and there is a disadvantage that the manufacturing cost is increased. Further, a drawback common to the above-described conventional methods is that, when bonding a grooved plate having an ink passage groove and a substrate provided with a piezoelectric element that generates energy acting on ink, each alignment is performed. Is difficult to carry out with high accuracy and lacks in mass production.

As a method of manufacturing an ink jet head capable of solving these disadvantages, a method of forming an ink passage wall by a cured film of a photosensitive resin is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 57-4.
No. 376 discloses this. According to this method,
The ink flow path is finely processed with high precision, accuracy, and good yield. In addition, mass production is easy, and an inexpensive inkjet head can be provided, which is an excellent method.

However, in the ink jet head provided by the improved manufacturing method as described above, although the above-mentioned drawback has been solved, the adhesion between the substrate and the cured photosensitive resin film gradually decreases with long-term immersion of the ink. However, minute cracks occur, which affects the rectilinearity of the ink droplets, that is, the impact point accuracy. In recent years, high-resolution image quality has been demanded by high-density nozzles in inkjet recording systems,
It was a major obstacle.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has high durability against impacts and ink solvents, and has been miniaturized with high reliability for a long period of time. An object of the present invention is to provide an inkjet head having an ink passage and a simple manufacturing method for manufacturing the inkjet head.

[0007]

According to the method of manufacturing an ink jet head of the present invention, a metal layer is formed on a substrate and a cover, respectively, and a photosensitive resin is laminated on the metal layer on the substrate and the cover, respectively. A step of forming ink channels in the photosensitive resin formed on the substrate side and the cover side, and a step of laminating and exposing the ink channels formed on the substrate side and the cover side to face each other. It is characterized by the following. Further, in the method of manufacturing an ink jet head, after the step of forming the ink flow paths in the photosensitive resin formed on the substrate side and the cover side, respectively, the bottom surface of the ink flow paths formed on the substrate side and the cover side is formed. A step of removing the exposed metal layer by etching. In the method for manufacturing an ink jet head, the cover is a diaphragm.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 to FIG. 4 are schematic views for explaining the configuration of the ink jet head of the present invention and the manufacturing steps thereof.

First, FIG. 1 shows that a thin metal layer 10 is formed on an appropriate substrate 1 such as glass, ceramic, plastic, etc., and then the photosensitive layer is heated to about 80 ° C. to 150 ° C. on the metal layer. Dry film resist 2 which is a film
(Film thickness, about 25μ to 200μ) from 10 to 100mm / m
Lamination is performed under the conditions of a pressure of 1 to 3 kg / cm ^{2 at} an in speed. Next, exposure is performed by a light source 4 from above a photomask 3 having a predetermined pattern on a dry film resist 2 provided on a substrate 1 (arrow in the figure). At this time, the pattern 3P sufficiently covers the area of the ink flow path on the substrate 1, and the pattern 3P does not transmit light. Therefore, the dry film resist 2 in the area covered with the pattern 3P is not exposed. When the exposure is performed as described above, the dry film resist 2 outside the pattern 3P undergoes a polymerization reaction and is hardened, and becomes insoluble in the solution.
On the other hand, the unexposed dry film resist 2 does not cure and remains dissolved and soluble. After the exposure operation, the dry film resist 2 is immersed in a volatile organic solvent, for example, trichloroethane to dissolve and remove (hereinafter, development) the unpolymerized (uncured) resist, as shown in FIG. Then, a cured resist wall 2H is formed on the substrate 1 as an ink flow path. Thereafter, the metal layer 10 forming the lower surface of the ink flow path formed by the cured resist wall 2H is peeled off with a predetermined etchant, so that the ink flow path is formed on the cured resist wall 2H and the substrate 1 surface. Composed of

Next, as shown in FIG. 3, a thin metal layer is formed on the diaphragm 6 in the same manner as the substrate, and the dry film resist 2 used for forming the flow path is similarly laminated on the metal layer. Then, exposure and development are performed in accordance with the above-described procedure to form a cured resist wall 2P on which a pattern similar to that of the ink flow path is printed. Thereafter, the diaphragm 6 is laminated on the cured resist wall 2H with the surface on which the pattern is formed facing the substrate 1. Thereafter, in order to bond the cured resist wall 2H on the substrate side and the cured resist wall 2P on the diaphragm side, the substrate 1 and the cured resist wall 2 for forming the ink flow path are bonded.
After P and 2H and the diaphragm 6 are brought into close contact with each other, re-exposure is performed by the light source 4 as in FIG. The ink flow path forming cured resist walls 2P and 2H are not completely cured at the development stage and have a self-adhesive action. Therefore, by performing re-exposure, the resist walls 2P and 2H are brought into close contact with each other and are cured and adhered. You. At this time, in addition to bonding the resist walls 2P and 2H, in order to improve solvent resistance, high energy exposure (ultraviolet irradiation 10 to 30 j / cm ² ) or thermal polymerization (10 to 130 ° C. to 160 ° C.) is performed. It is preferable to perform a step (heating for about a minute) or to use them together.

As described above, as shown in FIG. 4, the photo-cured dry film serves as a side wall, and the upper and lower surfaces of the groove have the ink flow path 5 composed of the diaphragm 6 surface and the substrate 1 surface, respectively. Is formed.

According to the above-described method for manufacturing an ink jet head, the adhesion between the substrate and the cured photosensitive resin film is significantly increased with the long-term immersion of the ink, and the nozzle holes serving as the ink droplet ejection holes are stabilized. Since the propulsion of the ink droplets, that is, the accuracy of the impact point is improved, it is possible to obtain high-resolution image quality by the high-density nozzle of the ink jet recording system.

In the above embodiment, after the cured resist wall 2H is formed on the substrate 1, the cured resist wall 2H is formed.
Although the metal layer 10 covering the lower surface of the ink flow path 5 formed by the above process is peeled off, the ink flow path 5 without performing this step can be manufactured. However, if the used metal layer 10 remains in the ink flow path 5, it may be eluted in the ink and deteriorate the ink, or the ink flow path may be clogged. It is desirable.

In the method of the present invention, the metal layer 10
In general, all common metals can be used, especially good adhesion with commercially available dry film resist,
Cu, Au, Fe, Ni, Cr and the like are desirable. In addition, a transparent electrode metal film (IT
O, SiO ² , InO ^2, etc.) are also effective.

FIG. 4 is a schematic perspective view showing the appearance of the ink jet head after the completion of the above steps. In FIG. 4, 5A, 5
B and 5C are ink supply paths,
Cavity, nozzle. A piezoelectric element 7, which is an ink ejection energy generator, is adhered on the vibration plate located in the cavity portion by a desired method.

After the joining of the substrate having the grooves formed therein and the diaphragm is completed, the substrate is cut along the line OO in FIG. This is performed in order to optimize the distance between the piezoelectric element 7 and the nozzle path 5 in the ink flow path, and the region to be cut here is appropriately determined. At the time of this cutting, a dicing method usually used for a semiconductor is adopted.

Further, the nozzle is not affected by the position of the cavity and the piezoelectric element, and can be installed on any surface of the cavity portion. As an example, as shown in FIG. 5, a nozzle hole is provided in the substrate 1.

In the embodiment described above with reference to the drawings, a dry film type, that is, a solid film is used as the photosensitive composition (photoresist) for forming a groove. However, the present invention is not limited to this. Not something
Liquid photosensitive compositions can of course also be used.

As a method for forming the photosensitive composition coating film on the substrate, in the case of a liquid, a method using a squeegee used in the production of a relief image, that is, a high-sensitivity film corresponding to a desired photosensitive composition film thickness. This is a method in which a wall is placed around a substrate and a squeegee is used to remove excess composition. In this case, the viscosity of the photosensitive composition is 100 cp to 30 cp.
A range of 0 cp is desirable, and the height of the wall needs to be determined in consideration of a reduction in evaporation of the solvent component of the photosensitive composition.

On the other hand, in the case of a solid, the photosensitive composition sheet is stuck on a substrate by heating and pressing. In the present invention, it is more advantageous to use a solid film type because the thickness can be easily and accurately controlled in handling.

Examples of such a solid sheet include permanent photopolymer coating RISTON (Solder mask) 730S and 740 manufactured by DuPont.
S, 730FR, 740FR, and SM1 are commercially available photosensitive resin sheets. In addition, as the photosensitive composition that can be used in the present invention, there are many photosensitive compositions used in the field of ordinary photolithography such as a photosensitive resin and a photoresist, for example, diazo resin, P-diazoquinone, for example, a photopolymerization type photopolymer using a vinyl monomer and a polymerization initiator, a dimerization type photopolymer using a sensitizer with polyvinyl cinnamate, and the like, Mixtures, polyether-type photopolymers obtained by copolymerizing 4-glycidylethylene oxide with benzophenone or glycidyl chalcone, copolymers of N, N-dimethylmethacrylamide with, for example, acrylamidobenzophenone, unsaturated polyester-based photosensitive resins (for example, PR (Asahi Kasei), Tevista (Teijin), Sonne (Kansai Paint), etc., unsaturated urethane oligomer-based photosensitive resin, photosensitive composition obtained by mixing photopolymerization initiator and polymer with bifunctional acrylic monomer, dichromic acid System-based photoresist, non-chromium-based water-soluble photoresist, polyvinyl cinnamate-based photoresist, cyclized rubber-azide-based photoresist, and the like.

[0022]

As described above, the method for manufacturing an ink jet head according to the present invention comprises the steps of forming a metal layer on a substrate and a cover, respectively, and laminating a photosensitive resin on the metal layers on the substrate and the cover, respectively. A step of forming ink flow paths in the photosensitive resin formed on the substrate side and the cover side, and a step of laminating and exposing the ink flow paths formed on the substrate side and the cover side to face each other. The ink flow formed on the substrate side and the cover side is formed by dividing the ink flow path into the substrate side and the cover side in the photosensitive resin firmly adhered to the substrate and the cover via the metal film by having the ink flow path. The depth of the groove serving as a path can be reduced, and the developing step can be performed easily in a short time, and a cured resist wall for forming an ink flow path with excellent dimensional accuracy can be formed. Further, there is an effect that the metal film formed on the ink flow path forming cured resist wall and exposed on the bottom surface of the ink flow path can be easily removed by etching. Further, in the method of manufacturing an ink jet head, after the step of forming the ink flow paths in the photosensitive resin formed on the substrate side and the cover side, respectively, the bottom surface of the ink flow paths formed on the substrate side and the cover side is formed. By having a step of removing the exposed metal layer by etching, the metal layer dissolves into the ink in the ink flow path, thereby altering the quality of the ink,
Since the ink flow path is not clogged, there is an effect that a more reliable inkjet head can be provided. Therefore, according to the method for manufacturing an ink jet head of the present invention, a highly reliable ink jet head having excellent accuracy can be easily provided in a short time.

(1) Since the adhesive strength between the substrate and the photosensitive resin is increased, the photosensitive resin does not peel off from the substrate even when cutting the formation of the ink ejection port which is particularly shocking.

(2) The solvent resistance of the bonded portion is improved, and the use of an ink containing a solvent such as ethylene glycol enables
The passage wall between the substrate and the cured photosensitive resin film does not peel off.

(3) Since the shape stability of the ink discharge port is high, the ink landing point accuracy with time is high.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for manufacturing an ink jet head of the present invention.

FIG. 2 is a diagram showing a method for manufacturing an ink jet head of the present invention.

FIG. 3 is a diagram showing a method for manufacturing an ink jet head of the present invention.

FIG. 4 is a diagram showing an embodiment of the ink jet head of the present invention.

FIG. 5 is a diagram showing another embodiment of the ink jet head of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 dry film 2P, 2H cured resist wall 3 photomask 3P photomask pattern 4 light source 5 ink flow path 5A nozzle 5B cavity 5C supply path 6 diaphragm 7 piezoelectric element

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-172750 (JP, A) JP-A-57-208258 (JP, A) JP-A-61-255868 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) B41J 2/16 C03C 29/00 C04B 37/02

Claims (3)

(57) [Claims] A step of forming a metal layer on the substrate and the cover; a step of laminating a photosensitive resin on the substrate and the cover-side metal layers, respectively; A method for manufacturing an ink jet head, comprising: forming an ink flow path in a photosensitive resin; and laminating and exposing the ink flow paths formed on the substrate side and the cover side to face each other. 2. The method according to claim 1, wherein after the step of forming ink flow paths in the photosensitive resin formed on the substrate side and the cover side, the metal exposed on the bottom surface of each of the ink flow paths formed on the substrate side and the cover side. 2. The method according to claim 1, further comprising the step of removing the layer by etching. 3. The method according to claim 1, wherein the cover is a diaphragm.