JP3158669B2 - Inkjet recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head, and more particularly, to an improvement in an ink jet recording head for generating recording droplets used in an ink jet recording system.

[0002]

2. Description of the Related Art Generally, an ink jet recording head applied to an ink jet recording system is formed as an ink discharge port, an ink flow path, and an energy generator for forming flying droplets, which are formed as a part of the ink flow path. Further, in a multi-nozzle type recording head having a plurality of ink flow paths in which ink discharge ports are provided one-to-one in the ink flow paths, a common ink chamber is provided. Is manufactured precisely and accurately under micromachining.

The precision and accuracy of the formation of the ink flow path in the production of the recording head depend on the droplet generation efficiency, the energy saving rate, the stability and uniformity of the droplet generation, and the quality of the head itself. In particular, the demand for high-density multi-nozzle type recording heads has increased in recent years, and its manufacturing method requires precise and accurate ultra-fine processing technology. From the point of view, good yield is required in terms of cost reduction.

The following method is reported in Japanese Patent Publication No. 62-59672 as a manufacturing method for improving the configuration accuracy of the ink jet recording head.

As shown in FIG. 8, a predetermined number of active elements 2 such as a heating element and a piezoelectric element as an energy source for applying energy for generating liquid droplets to a liquid are fixedly provided at a predetermined position on a substrate 1. . A photosensitive composition layer having a predetermined thickness is provided on the surface of the substrate 1 on which the active elements 2 are provided, and the ink discharge port 3, the ink discharge path 4, the cavity, and the like are formed by a usual photolithography method. 5. Ink channel groove 7 for forming an ink channel of ink supply path section 6
To form Next, an upper lid 8 is joined to the active element 2 side of the substrate 1 provided with the ink flow channel 7 to manufacture an ink jet recording head. In the above method, accurate positioning is possible, and high-density fine processing is easy, so that an advantage is required in that a high-density multi-nozzle recording head having high characteristics can be produced with high yield.

However, in a high-density multi-nozzle recording head manufactured by such a conventional method, FIG.
As shown in FIG. 2, the side wall 9 between the cavities is formed of the cured layer of the photosensitive composition, and thus the active element 2
Pressure fluctuations in the cavities due to the ink ejection energy generated from the cavities deform the side walls 9 between the cavities, and thus easily affect the pressure fluctuations in the adjacent cavities, and restrict the thickness of the side walls and the density of the ink flow path. It has disadvantages that arise.

[0007] As a method for improving the above disadvantages,
As shown in FIG. 10, after forming an ink flow channel 7 in the substrate 1 and joining the upper lid 8 to close the ink flow channel 7, a groove 10 is formed in the side wall 9 between the upper lid 8 and the cavity by dicing or the like. A method has been proposed in which the side wall 9 is provided to separate the side walls 9 so as to reduce the transmission of the pressure fluctuation between the adjacent cavities. However, in the above method,
Although the effect of reducing the influence between the adjacent cavities is required, (1) it is difficult to form the groove 10 deep, and the effect on the above problem is low. (2) Since the wall thickness of the side wall 9 becomes thinner as the density of the head increases, the width and the positional accuracy of the groove 10 are restricted.
(3) The bonding area between the upper lid 8 and the side wall 9 is reduced, and the sealing performance against pressure fluctuation in the cavity 5 is reduced. It has such disadvantages.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has been made in view of the above-mentioned problems. It is an object of the present invention to provide a new method for manufacturing an ink jet recording head having high performance. It is another object of the present invention to provide a method for manufacturing an ink jet recording head having a structure in which ink passages are finely processed with high precision and faithful to the design with a simple method and with high yield. It is another object of the present invention to provide a method of manufacturing an ink jet recording head having excellent use durability.

[0009]

According to the present invention, there is provided an ink jet recording head comprising a plurality of ink discharge ports, a plurality of cavities respectively communicating with the ink discharge ports, and an active space formed to correspond to the cavities. An ink-jet recording head comprising a photosensitive resin and a side wall for partitioning the plurality of cavities, wherein the side wall comprises an uncured portion and a cured portion of the photosensitive resin. .

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 are a schematic view and a cross-sectional view for explaining the configuration of the ink jet head of the present invention and the procedure for manufacturing the same.

First, FIG. 1 shows a dry film resist 11 (thickness: about 2 ° C.) heated to about 80 ° C. to 150 ° C. on a suitable substrate 1 such as glass, ceramic or plastic.
5μ to 300μ) at a speed of 10 to 100 mm / min,
Multi-layer lamination (two layers in the figure) is performed under a pressure of 1 to 3 kg / cm 2. Next, on the dry film resist 11 provided on the substrate 1, the ink flow path (ink discharge ports 3, ink discharge paths 4, cavities 5, ink discharge paths 6) pattern 20 and the uncured portions 9B in the side walls between the cavities are formed.
Primary exposure is performed by the light source 13 from above the photomask 12A having the pattern 21.

At this time, the pattern does not transmit light. Therefore, the dry film resist 11 in the area covered with the pattern is not exposed. When the exposure is performed as described above, the dry film resist 11 outside the pattern is exposed.
Cause a polymerization reaction to be cured, and become solution-insoluble. On the other hand, the unexposed dry film resist 11 does not cure and remains dissolved and soluble. FIG. 2 is a sectional view taken along line AA ′ in FIG. 1 after primary exposure. The dry film resist 11 under the uncured portion 9B pattern 21 in the side wall between the ink flow path pattern 20 and the cavity in the photomask 12A remains undissolved without being exposed as described above, and the other portions (shaded lines) Part) is exposed and becomes solution-insoluble.

Thereafter, as shown in FIG. 3, a dry film resist 13 is further laminated on the dry film resist 11 by the method described above. Next, a photomask 12 is formed on the dry film resist 13.
Secondary exposure is performed by the light source 13 from above the photomask 12B having only the ink flow path pattern 20 of A. At this time, the dry film resists 11 and 13 are
The photosensitive resin is formed from photosensitive resins having different conditions (curing exposure wavelength, curing temperature, etc.) for causing a polymerization reaction and curing.
The next exposure wavelength was adjusted to the dry film resist 13 so that the uncured portion was not cured by the first exposure. The 9B portion of the dry film resist 11 did not undergo a curing reaction even after the second exposure, and only the 13 layers of the dry film resist were cured. Produces a reaction. FIG. 4 is a sectional view taken along the line AA ′ in FIG. 3 after the secondary exposure.

After the exposure operation, the dry film resists 12 and 13 are immersed in a volatile organic solvent such as trichloroethane to dissolve and remove the uncured resist (hereinafter referred to as development). As shown, on the substrate 1, an ink flow channel groove 7 composed of the ink flow pattern 20 and a side wall 9 composed of a cured portion 9A and an uncured portion 9B are formed.

Thereafter, as shown in FIG. 6, an upper lid 8 is joined to the dry film resist 13 layer on the side wall 9 between the cavities to close the ink flow channel 7, thereby forming the side wall 9 and the upper surface of the ink flow channel. And the lower surface of the substrate 1
Is formed.

In the ink flow path formed as described above, as shown in FIG. 7, the pressure fluctuation in the cavity due to the ink ejection energy generated from the active element is absorbed by the uncured portion of the side wall 9, and It works to mitigate the effect between adjacent cavities. Therefore, the thickness of the side wall can be reduced as compared with the side wall formed entirely of the hardened portion, and the density of the nozzle flow path in the multi-nozzle head can be further increased.

It is needless to say that the above-described effect is more effective by reducing the thickness of the dry film resist 13 in the uppermost layer forming the side wall of the ink flow path.

In the embodiment described above with reference to the drawings, a dry film resist type, that is, a solid type is used as the photosensitive composition for forming a groove.
In the present invention, the present invention is not limited to this, and a liquid photosensitive composition can of course be used, and the same effect can be obtained by applying a liquid photosensitive resin only to the uppermost layer. Besides, forming the entire side wall between the cavities is also an effective means. Then, 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 at the time of producing a relief image, that is, a wall having a height corresponding to a desired photosensitive composition film thickness. This is a method in which the excess composition is removed around the substrate by a squeegee. In this case, the viscosity of the photosensitive composition is desirably in the range of 100 cp to 300 cp, and the height of the wall needs to be determined in consideration of a decrease 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 heated and pressed on a substrate and adhered. Therefore, in the present invention, the thickness can be easily and accurately controlled in handling. It is advantageous to use a solid film type.

Such a solid sheet is, for example, a permanent photopolymer coating RISTON (Solder mask) 730S, 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 polyvinyl cinnamate or the like and a sensitizer, a mixture of orthonaphthoquinonediazide and a novolak type phenol resin. A mixture, a polyether-type photopolymer obtained by copolymerizing 4-glycidylethylene oxide with benzophenone or glycidyl chalcone, a copolymer of N, N-dimethylmethacrylamide with, for example, acrylamidobenzophenone, an unsaturated polyester-based photosensitive resin (for example, PR (Asahi Kasei), Tevista (Teijin), Sonne (Kansai Paint), etc., unsaturated urethane oligomer-based photosensitive resin, photosensitive composition obtained by mixing a bifunctional acrylic monomer with a photopolymerization initiator and a polymer, dichromic acid Photoresist, non-chromium-based water-soluble photoresist, polyvinyl cinnamate-based photoresist, cyclized rubber-azide-based photoresist, and the like.

[0021]

The effects of the present invention described above can be listed as follows.

(1) The transmission of the pressure fluctuation in the cavity between the adjacent nozzles can be reduced, and the mutual influence between the nozzles is small, so that the reliability at the time of driving and the printing quality can be improved.

(2) The wall thickness between the cavities can be made smaller, and a multi-nozzle head with higher density can be manufactured.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line A-A 'in FIG.

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

FIG. 4 is a sectional view taken along line A-A 'in FIG.

FIG. 5 is an explanatory view showing a method for manufacturing an ink jet head of the present invention.

FIG. 6 is an explanatory view showing a method for manufacturing an ink jet head of the present invention.

FIG. 7 is a sectional view of an embodiment of the ink jet head of the present invention.

FIG. 8 is an explanatory view showing a conventional example of an ink jet head of the present invention.

FIG. 9 is an explanatory diagram showing a conventional example of an ink jet head of the present invention.

FIG. 10 is an explanatory view showing a conventional example of an ink jet head of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Active element 3 Ink ejection port 4 Ink ejection path part 5 Cavity 6 Ink supply path part 7 Ink channel groove 8 Top lid 9 Side wall 9A Cured part of side wall 9 Uncured part of side wall 10 Groove 11 Dry film resist 12A Photomask 12B Another photomask 13 Another dry film resist 20 Ink flow path pattern 21 Uncured portion pattern on side wall

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (4)

(57) [Claims] A plurality of ink ejection ports, a plurality of cavities respectively communicating with the ink ejection ports, and an active element formed to correspond to the cavities;
An ink jet recording head in which a side wall partitioning the plurality of cavities is formed of a photosensitive resin, wherein the side wall includes an uncured portion and a cured portion of the photosensitive resin. 2. The ink jet recording head according to claim 1, wherein a side wall between the cavities is made of a multilayer photosensitive film. 3. An ink jet recording head according to claim 2, wherein the uppermost film of the photosensitive film constituting the side wall between the cavities is entirely cured. 4. The ink jet recording head according to claim 2, wherein the uppermost film of the photosensitive film constituting the side wall between the cavities is thinner than the lower layer.