JPH0645241B2 - Method for manufacturing ink jet recording head - Google Patents

Description

The present invention relates to an inkjet recording head, and more particularly to a method for manufacturing an inkjet recording head for recording by ejecting recording ink used in a so-called inkjet recording system.

An ink jet recording head applied to an ink jet recording method generally includes an ejection port (orifice), an ink passage, and an ink ejection energy generating section provided in a part of the ink passage.

Conventionally, as a method for producing such an ink jet recording head, for example, after forming fine grooves on a substrate made of glass or metal by cutting or etching, the plate on which the grooves are formed is joined with an appropriate plate. A method of forming an ink passage is known.

However, in the head created by such a conventional method,
It is difficult to obtain a precise ink passage because the inner wall surface of the ink passage to be cut is too rough or the ink passage is distorted due to the difference in etching efficiency. Variation was easy to occur. In addition, there is a defect that the substrate is likely to be chipped or cracked during cutting, resulting in poor manufacturing yield. When etching is performed, there are many manufacturing steps, which causes a problem of increasing manufacturing cost. Further, as a problem common to the above-mentioned conventional methods, a piezoelectric element, a heating element, or the like that generates energy for ejecting ink from the ink ejection port by acting on the grooved plate in which the ink passage groove is formed and the ink It is difficult to accurately perform the positioning of the ink ejection energy generating element and the cover plate provided with the ink ejection energy generating element, which is not suitable for mass production.

As a method of manufacturing an ink jet recording head capable of solving these problems, a method of forming an ink passage wall with a cured film of a photosensitive resin which is a curable resin is disclosed in, for example, Japanese Patent Laid-Open No. 57-4.
Known by No. 3876. According to this method, the ink passages are finely processed with high precision, high yield, and high yield. In addition, it can be said that the method is easy to mass-produce and is excellent in cost.

However, although the above problems have been solved by the improved manufacturing method as described above, the adhesion between the substrate and the cured film of the resin is gradually decreased due to long-term immersion of the ink, and fine cracks are generated. This affects the straightness of the droplet, that is, the accuracy of the landing point. Further, the curable resin causes shrinkage and deformation in the process of performing curing treatment such as ultraviolet irradiation and heat treatment, which is one of the causes for promoting minute peeling. Further, when the orifice is cut on the downstream side of the ink passage, distortion is caused by this cutting, which causes minute peeling of the cured film of the resin from the substrate. This has become a problem to be solved in recent years when the inkjet recording system is required to have high density and high quality.

The present invention has been made in view of the above problems and problems to be solved, and an object of the present invention is to provide a novel method for manufacturing an inkjet recording head with high accuracy and high reliability. Another object of the present invention is to provide a method for manufacturing an inkjet recording head having excellent durability. The present invention, which has achieved various objects as described above, provides a method for manufacturing an inkjet recording head in which a curable resin is used as a member that forms an ink passage formed on a substrate, and after the curing treatment step of the curable resin, It is characterized by including a step of annealing the curable resin at a temperature not lower than the glass transition temperature (Tg) of the curable resin.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, a photosensitive resin will be used as the curable resin for description.

First, in the process of FIG. 1, the ink discharge energy generating element 2 such as a heating element or a piezoelectric element is arranged on a substrate 1 made of glass, ceramic, metal or the like, and from the above, an electric insulating property is provided, An electrically insulating layer such as SiO ₂ , Ta ₂ O ₅ or glass or an ink resistant layer such as Ta (collectively referred to as protective layer 3) is covered. A signal input electrode is connected to the ink ejection energy generating element 2.

Next, in the process shown in FIG. 2, the surface of the protective layer 3 of the substrate 1 is cleaned, and the dry film photoresist (photosensitive resin) 4 (film thickness of about 25 to 100 μm) heated to about 80 to 105 ° C.
m) is laminated at a speed of 0.5 to 4 f / min and a pressure of 1 to ³ kg / cm ² . Then, a photomask 5 having a predetermined pattern is overlaid on the dry film photoresist 4 provided on the surface of the substrate, and exposure is performed from above. At this time, the installation position of the ink ejection energy generating element 2 and the photomask 5
The pattern alignment is performed by drawing alignment marks on the substrate 1 and the photomask 5, respectively.

FIG. 3 is a view showing a process in which the unexposed portion of the dry film photoresist 4 is dissolved and removed by a developing solution containing a desired organic solvent such as 1,1,1-trichloroethane, and the ink passage 8 is formed. To be done. Next, the dry film photoresist 4P cured film left as the opposite walls of the ink passage on the substrate 1 is heat-cured (for example, heated at 150 to 250 ° C. for 30 minutes to 6 hours to further improve ink resistance. Do)
Alternatively, UV irradiation is performed (for example, UV intensity of 50 to 200 mW / cm ² or more). It is also effective to use both of them. FIG. 4 is a view showing a flat plate 7 fixed by an adhesive as a wall facing the substrate 1 in which the ink passage 8 is formed by the dry film photoresist 4P. (6 indicates an adhesive layer). In the step shown in FIG. 4, as a concrete method for providing a cover, 1) a flat plate 7 made of glass, ceramic, metal or the like is spinner coated with an epoxy adhesive to a thickness of 3 to 4 μm, and then preheated. The adhesive is so-called B-staged, and is adhered onto the hardened photoresist film 4P to fully harden the adhesive. Alternatively, 2) there is a method in which a flat plate 7 made of a thermoplastic resin such as acrylic resin, ABS resin, or polyethylene is directly heat-sealed on the hardened photoresist film 4P.

Here, FIG. 5 is a schematic perspective view showing the outer appearance of the ink jet recording head after the step shown in FIG. 8-1 in the figure
Is an ink supply chamber, 8-2 is an ink fine channel, and 9 is a through hole for connecting an ink supply pipe (not shown) to the ink supply chamber 8-1.

After the bonding of the substrate having the ink passages and the flat plate is completed in this way, in the present embodiment, CC ′ of FIG.
Cut along the line. This is because the ink ejection energy generating element 2 and the ejection port 8-3 are provided in the ink fine channel 8-2.
This is carried out in order to further optimize the interval between and, and the region to be cut here is appropriately determined. At the time of this cutting, the dicing method usually adopted in the semiconductor industry is adopted. FIG. 6 is a sectional view taken along line ZZ ′ of FIG.

In the present embodiment, thereafter, the head itself is annealed at a temperature equal to or higher than Tg (glass point transfer) of the cured film of the photosensitive resin used for forming the ink passage. In the above example, as the photosensitive resin, for example, Hitachi Chemical Co., Ltd.
Using Photec SR3000-35 manufactured by, the annealing temperature is 105
It may be heated at about 150 ° C for about 1 hour and then slowly cooled (Tg = 105 ° C in this case). In the present embodiment, a liquid resin can be used in addition to the above-described dry film type, that is, the solid type is used to form the ink passage. In that case, a resin film is formed by a method using a squeegee used when producing a relief image (viscosity of the liquid is 100 to 300 cP).

In the case of a solid, a resin sheet is heat-pressed onto the substrate. In the present invention, it is more advantageous to use the solid film type in terms of handling and controlling the thickness easily and accurately.

Examples of such solid photosensitive resin sheets include permanent polymer coating RISTON manufactured by Dubon Co.,
Solder Mask 730S, 740S, 730FR, 740FR, SMI,
KAPTON XA-A3, XA-B3, XA-A1, XA-M3, XA-C3;
Hitachi Chemical Photec, PHT series, SR series, Asahi Kasei
DFR, E-15, P-25, P-38, T-50; Nitto Denko NEOTRICK E type, T type; Tokyo Ohka Thiokol Laminar GT, Laminar GSI, Laminar TO, Laminar TA; etc. The photosensitive resin commercially available in.

In addition, as a photosensitive resin that can be used in the present invention,
For example, diazozylene, diazoquinone, and further, for example, a photopolymerization type photopolymer that uses a vinyl monomer and a polymerization initiator, a two-quantum type photopolymer that uses polovinylcinnamate and a sensitizer, orthonaphthoquinonediazide is a novolak type phenol. A mixture with a resin, a mixture of polyvinyl alcohol and a diazo resin, a polyether type photopolymer obtained by copolymerizing 4-glycidyl ethylene oxide with benzophenone or glycidyl chalcone,
Copolymer of N, N-dimethylmethacrylamide with, for example, acrylamidebenzophenone, unsaturated polyester photosensitive resin [for example, APR (Asahi Kasei), Tevista (Teijin), Sonne (Kansai Paint), etc.], unsaturated urethane oligomer type photosensitive Resin, photosensitive composition in which bifunctional acrylic monomer photopolymerization initiator and polymer are mixed, dichromic acid photoresist, non-chromium water-soluble photoresist,
Examples thereof include polyvinyl cinnamate photoresists and cyclized rubber-azide photoresists.

The effects of the present invention described in detail above include the following.

1) When the curable resin is annealed at a high temperature of Tg or higher after the curing treatment, the stress generated by the curing shrinkage is relaxed, and as a result, the adhesive force with the substrate is relatively increased with respect to the stress, and the photosensitivity is improved. The minute peeling of the cured film of the resin from the substrate did not proceed.

2) In particular, when cutting is performed to optimize the distance between the ink ejection port and the energy generating element, annealing at a temperature of Tg or higher after cutting improves the shape stability of the ink ejection port, and High accuracy of ink impact point.

These effects of the present invention will be specifically described by the following examples.

The material of the surface of the protective layer was changed between each example, and an inkjet recording head having 10 ink ejection ports was prototyped in accordance with the steps of the above-mentioned example (FIGS. 1 to 4). As the ink ejection energy generating element, heating elements were used in Examples 1 to 3 and Comparative Examples 1 to 3, and piezoelectric elements were used in Example 4 and Comparative Example 4. Of these, a normal head in which the substrate and the cured film of the photosensitive resin did not peel off was subjected to a dipping test for 1000 hours in a 80 ° C. solution of 20% water and 80% ethylene glycol. The results are shown in Table 1.
In the ink jet recording head Examples 1, 2, 3, and 4 annealed at a temperature of Tg or higher, peeling of the cured film of the resin from the substrate did not appear at all (annealing was performed at 120 ° C. for about 1 hour).

Further, the ink jet recording heads obtained in Example 1 and Comparative Example 1 were subjected to a 10 ⁸ pulse endurance printing test and the landing point accuracy was examined. In Example 1, ± 10 μm / 2
While the print quality was very good at the flight distance of mm,
In Comparative Example 1, the flight distance was ± 60 μm / 2 mm, and good printing could not be obtained.

[Brief description of drawings]

1 to 4 are schematic views showing the manufacturing steps of the ink jet recording head of the present invention. FIG. 5 is a perspective view of an ink jet recording head obtained by the method of the present invention, and FIGS. 6 and 7 are sectional views thereof. 1 ... Substrate 2 ... Ink ejection energy generating element, 3 ... Protective layer, 4 ... Photosensitive resin, 4P ... Ink passage wall, 5 ... Photomask, 6 ... Adhesive layer, 7 ... Cover , 8 ... Ink passage, 8-1 ... Ink supply chamber, 8-2 ... Ink fine channel, 8-3 ... Ink ejection port 9 ... Through hole, 10 ... Ink supply pipe.

Claims (2)

[Claims] 1. A method of manufacturing an ink jet recording head, wherein a curable resin is used as a member forming an ink passage formed on a substrate, wherein a glass transition point of the curable resin is set after a curing treatment step of the curable resin. A method of manufacturing an inkjet recording head, comprising a step of annealing the curable resin at a temperature (Tg) or higher. 2. The method for manufacturing an ink jet recording head according to claim 1, further comprising the step of forming an orifice end face by cutting a part of the ink passage.