JPH05212870A - Production of ink jet recording head - Google Patents

Abstract

PURPOSE:To obtain a precise recording head having high reliability and durability by a manufacturing method containing an exposure process forming ink passagers to a photosensitive resin, an unnecessary part removing process and a process for the reaction completion treatment of the coupling agent in the resin and a substrate. CONSTITUTION:Heating elements are arranged on a metal substrate corresponding to ink passages to be covered with an electric insulating layer 3 composed of SiO3. Next, the surface of the substrate 1 is purified to be dried at 50 deg.C for 10min and subsequently coated with a photosensitive resin compsn. containing a coupling agent by a method removing the excessive compsn. by a squeezee to be dried at room temp. Then, a photomask 5 having a predetermined pattern is superposed on the photosensitive resin layer 3 provided on the surface of the substrate 1 and the photosensitive resin layer 4 is exposed through the photomask 5. Next, the unexposed part of the exposed resin layer 4 is dissolved and removed by a developing solution composed of a predetermined org. solvent and, subsequently, heat treatment or the irradiation with ultraviolet rays is performed in order not only to enhance the ink resistance of the exposed part 4P of the resin layer 4 left on the substrate but also to complete the reaction of the coupling agent in the resin layer 4 with the substrate.

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 a method of manufacturing an ink jet recording head for producing recording ink droplets used in a so-called 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 provided with a fine ink ejection port (orifice), an ink passage, and an ink ejection pressure generating portion provided in a part of this ink passage.

Conventionally, as a method of producing such an ink jet recording head, for example, after a fine groove is formed on a glass or metal plate by cutting or etching, the plate on which the groove is formed is used by another suitable method. A method of joining with a plate to form an ink passage is known.

However, in the head produced by such a conventional method, the inner wall surface of the ink passage to be cut is excessively rough, or the ink passage is distorted due to the difference in etching rate. It is difficult to obtain a passage, and variations in the ink ejection characteristics of the manufactured inkjet recording head are likely to occur. In addition, there is a problem that a chip is likely to be chipped or cracked during cutting, resulting in poor manufacturing yield. And when performing etching processing, there are many manufacturing steps,
There is a problem that it causes an increase in manufacturing cost. Further, as a problem common to the above-mentioned conventional methods, there are a grooved plate in which ink passage grooves are formed and a lid plate provided with a driving element such as a piezoelectric element or a heat generating element that generates energy acting on ink. It is difficult to accurately perform the respective alignments at the time of bonding, and mass production is lacking.

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 is disclosed in, for example, JP-A-57-4.
No. 3876, etc. According to this method, the ink passage is finely processed with high accuracy, accuracy, and yield. Further, it is an excellent method because it can be easily mass-produced and an inexpensive ink jet recording head can be provided.

However, in the ink jet recording head provided by the improved manufacturing method as described above, although the above-mentioned problems are solved, the adhesion between the substrate and the photosensitive resin cured film is gradually increased due to the long-term immersion of the ink. The amount of the ink drops, and slight peeling occurs, which affects the straightness of the ink droplet, that is, the accuracy of the landing point. Further, the photosensitive resin composition is irradiated with ultraviolet rays,
Shrinkage deformation occurs in the process of hardening treatment such as heat treatment,
This is one of the factors that contribute to the minute peeling.
This has become a major obstacle in recent years when the ink jet recording system requires high-resolution image quality with high-density nozzles. Therefore, the development of an ink jet recording head having a configuration that solves these problems has been earnestly desired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording head which is precise, has high reliability, and is excellent in use durability. In particular, it is an object of the present invention to provide a structure of an ink jet recording head capable of manufacturing a head having a structure in which an ink passage is precisely processed and is finely processed according to a design with a high yield by a simple method.

[0008]

The present invention, which has achieved such an object, uses a photosensitive resin on a substrate provided with an energy generating element for generating energy used for ejecting ink. In a method for manufacturing an ink jet recording head in which an ink passage is provided, an ink passage is formed in the photosensitive resin that contains a coupling agent for improving the adhesive force with the substrate and that is disposed on the substrate. Exposure step, a step of removing an unnecessary portion for forming an ink passage, and a reaction between the coupling agent in the photosensitive resin and the substrate with respect to the exposed photosensitive resin. And a step of performing a treatment for completing the method.

The present invention will be described in detail below with reference to the drawings. First, an embodiment of the present invention will be described according to the manufacturing process shown in FIGS.

In the process shown in FIG. 1, an energy generating element 2 is provided on a substrate 1 made of glass, ceramic, plastic, metal or the like, which generates energy used for ejecting ink corresponding to an ink passage. Arrange a desired number of heating elements or piezo elements that generate thermal energy,
In order to impart ink resistance and electrical insulation, SiO ₃ ,
An electric insulating layer 3 made of Ta ₂ O ₅ , Al ₃ O ₃ , Si ₃ N ₄ , BN, glass or the like is coated. If necessary, Ti, Cr, Ni, Ta, M may be added for the purpose of improving ink resistance.
A corrosion resistant metal such as o, W, Nb or a corrosion resistant alloy such as SUS or monel metal may be coated as the ink resistant layer. Although not shown, a signal input electrode is connected to the ink ejection pressure generating element 2.

Next, the surface of the substrate 1 obtained in the step of FIG. 1 is cleaned and dried at 80 to 150 ° C. for 10 minutes. A photosensitive resin composition containing a coupling agent on this substrate (Permanent Photopolymer Coating R manufactured by DuPont)
100 g of ISTON 730S was dissolved in 100 ml of methyl ethyl ketone, and γ-mercaptopropyltrimethoxysilane (molecular structure formula HS (CH ₂ ) ₃ Si was added thereto.
1 g of (OCH ₃ ) ₃ ) is added), that is, a wall having a height corresponding to the film thickness of the desired photosensitive resin composition is installed around the substrate and the squeegee is used to remove the excess composition. Was applied and dried at room temperature. The film thickness of the photosensitive resin layer 4 after drying was 74 ± 3 μm.
Generally, when applying by the squeegee method, the viscosity of the photosensitive resin composition is preferably in the range of 100 to 300 cps, and the height of the wall placed around the substrate depends on the evaporation of the solvent component of the photosensitive resin composition. It is necessary to decide in consideration of weight loss.

Then, as shown in FIG. 2, a photomask 5 having a predetermined pattern is superposed on the photosensitive resin layer 4 provided on the surface of the substrate, and then exposure is performed from above the photomask 5. At this time, the installation position of the ink ejection pressure generating element 2 and the position of the above pattern must be aligned by a known method.

FIG. 3 is an explanatory view showing a process in which the unexposed portion of the exposed photosensitive resin layer 4 is dissolved and removed by a developing solution made of a predetermined organic solvent such as trichloroethane. Next, the exposed portion 4P of the photosensitive resin layer left on the substrate 1
Heat treatment (for example, heating at 150 to 250 ° C. for 30 minutes to 6 hours) or ultraviolet irradiation (for example, 50 to 200 mW) to improve the ink resistance and complete the reaction between the silane coupling agent in the photosensitive resin layer and the substrate. / Cm ² or higher UV intensity). It is also effective to use both the heat treatment and the curing by ultraviolet rays.

In FIG. 4, a flat plate 7 as a cover is provided on a substrate 1 in which a groove 8 serving as an ink passage is formed by a cured dry photoresist which is a photosensitive resin cured film 4P cured after the above sufficient polymerization. It is a figure showing the place where it adhered or was simply crimped and fixed.

In the step shown in FIG. 4, a concrete method for providing a cover is as follows: 1) A flat plate 7 made of glass, ceramic, metal, plastic or the like is spinner coated to a thickness of 3 to 4 μm with an epoxy adhesive. After that, the adhesive 6 is preheated to be a so-called B stage, which is attached to the cured photoresist film 4P and the adhesive is fully cured. Alternatively, 2) there is a method in which a flat plate 7 made of a thermoplastic resin such as an acrylic resin, an ABS resin, or polyethylene is directly heat-sealed onto the hardened photoresist film 4P.

Here, the external appearance of the head after the step shown in FIG. 4 is shown in FIG. 5 in a schematic perspective view. In FIG. 5, 8-1 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) of the ink supply chamber 8-1.

As described above, after the flat plates having the grooves are joined to each other, the flat plates are cut along the line CC 'in FIG. This is done in order to optimize the distance between the ink ejection pressure generating element 2 and the ink ejection port 8-3 in the ink flow path 8-2, and the region to be cut here is appropriately determined. It For this cutting, the dicing method that is usually adopted in the semiconductor industry is adopted.

FIG. 6 is a sectional view taken along line ZZ 'of FIG. Then, the cut surface is polished and smoothed, and the ink supply pipe 10 is attached to the through hole 9 to complete the ink jet recording head (FIG. 7).

In the examples described above with reference to the drawings, a photosensitive resin composition (photoresist) for groove formation is used.
As the dry film type, that is, a solid one was once dissolved in a solvent and mixed with a coupling agent, but a liquid photosensitive resin composition mixed with a coupling agent can also be used. .. Of course, it is also possible to mix and use a coupling agent with a photosensitive resin composition having a composition suitable for the purpose of the manufacturer.

As a method for forming the coating film of the photosensitive resin composition on the substrate, a squeegee method used at the time of producing a relief image can be used in the case of a liquid. On the other hand, when the solvent is removed and the solvent is removed to form a sheet, the photosensitive resin composition sheet is heated and pressure-bonded onto the substrate to adhere the sheet.

Examples of the solid photosensitive resin include permanent photopolymer coating RI manufactured by DuPont.
There are commercially available products such as STON (solder mask) 730S, 740S, 730FR, 740FR, and SM1. In addition, examples of the photosensitive resin composition used in the present invention include many photosensitive resin compositions used in the field of ordinary photolinography such as a photosensitive resin layer and a photoresist. .. Examples of these photosensitive resin compositions include:
Diazoresin, P-diazoquinone, and further, for example, a photopolymerization type photopolymer using a vinyl monomer and a polymerization initiator, a monomerization type photopolymer using a polyvinyl cinnamate or the like and a sensitizer, an orthonaphthoquinone diazide and a novolak type phenol 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, N,
Copolymer of N-dimethylmethacrylamide and, for example, acrylamidebenzophenone, unsaturated polyester photosensitive resin [for example, APR (Asahi Kasei), Devista (Teijin), Sonne (Kansai Paint), etc.], unsaturated urethane oligomer photosensitive resin , A photosensitive resin composition in which a photopolymerization disclosing agent and a polymer are mixed in a bifunctional acrylic monomer, a dichromic acid photoresist, a non-chromium water-soluble photoresist, a polyvinyl cinnamate photoresist, a cyclized rubber-azide System photoresists and the like.

In the present invention, as the coupling agent to be contained in the photosensitive resin, in addition to γ-mercaptopropyltrimethoxysilane used in the above examples, generally, a silicon type coupling agent, an aluminum type coupling agent,
1 of the coupling agents classified as zirconium-based coupling agents and titanium-based coupling agents
More than one species can be used. It is preferable to select and use a coupling agent having a functional group that interacts with the functional group of the photosensitive resin, depending on the composition of the photosensitive resin used. Further, the addition amount of the coupling agent is appropriately in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the photosensitive resin. When the added amount of the coupling agent is small, the effect of improving the adhesion between the substrate and the cured photosensitive resin film is not recognized, while when the added amount is too large, the performance of the cured photosensitive resin film is impaired.

Of these coupling agents, Table 1 and Table 2 summarize the representative ones of silicon type coupling agents and titanium type coupling agents.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

EXAMPLES The effects of the present invention will be more specifically described by the following examples. Examples 1 and 2 and Comparative Examples 1 to 4 In each of the examples described above, the photosensitive resin used and the material of the protective layer of the uppermost substrate in contact with the photosensitive resin were changed. A large number of inkjet recording heads having 10 ink ejection ports were manufactured in accordance with the same process (FIGS. 1 to 7) as the example.

The photosensitive resin used in Examples 1 and 2 was prepared by dissolving 100 g of DuPont 730S dry film photoresist in 100 ml of methyl ethyl ketone and adding 1 g of γ-mercaptopropyltrimethoxysilane to the squeegee. 74 ± 3 μm depending on the method
Comparative Examples 1 and 2 in which γ-mercaptopropyltrimethoxysilane was not added, and the same film thickness was formed in the same manner, Comparative Examples 3 and 4
Then, a RISTON 730S dry film photoresist having a film thickness of 75 μm was used by pressing it as it was.

Of these prototype heads, a normal head in which the substrate and the photosensitive resin were not separated from each other was added to a solution of 20% water and 80% ethylene glycol at 80 ° C.
A time immersion test was performed. The results are shown in Table 3.

The inks obtained in Example 1 and Comparative Example 1
10 for jet recording heads ⁸ Durability printing of pulse
When a test was conducted, the ink landing point was found for the head of the example.
The accuracy was ± 12 μm / 2 mm, but the ratio was
The head of the comparative example had a flight distance of ± 60 μm / 2 mm.

[0033]

[Table 6]

[0034]

The effects of the present invention described in detail above are as follows.

1. The increased adhesion between the substrate and the photosensitive resin prevents the photosensitive resin from peeling off from the substrate even when the formation of the ink ejection port, which is particularly impacted, is cut.

2. The solvent resistance of the adhesive portion is improved, and the passage walls of the photosensitive resin cured film and the substrate are not separated even when an ink containing a solvent such as ethylene glycol is used.

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

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a manufacturing process of an inkjet recording head of the present invention, showing a cross-sectional view of a substrate on which an energy generating element and an electric insulating layer are provided.

FIG. 2 is a schematic diagram for explaining a manufacturing process of the inkjet recording head of the present invention, showing a cross-sectional view of a substrate which is provided with a photosensitive resin layer on the substrate surface shown in FIG.

FIG. 3 is a schematic diagram for explaining the manufacturing process of the inkjet recording head of the present invention, showing a cross-sectional view of the substrate in which the unexposed portion is dissolved and removed after the exposure shown in FIG.

FIG. 4 is a schematic view for explaining the manufacturing process of the inkjet recording head of the present invention, showing a cross-sectional view of the head in which a flat plate is provided on the substrate shown in FIG.

FIG. 5 is a schematic view for explaining the manufacturing process of the inkjet recording head of the present invention, and is a partial perspective view of the head shown in FIG.

FIG. 6 is a schematic diagram for explaining a manufacturing process of the inkjet recording head of the present invention, in which Z of the head shown in FIG.
The -Z 'line sectional view is shown.

FIG. 7 is a schematic diagram for explaining the manufacturing process of the inkjet recording head of the present invention, showing a cross-sectional view of a completed head obtained by attaching an ink supply pipe to the head shown in FIG.

Claims (1)

[Claims] 1. A method of manufacturing an ink jet recording head, wherein an ink passage is provided by using a photosensitive resin on a substrate provided with an energy generating element for generating energy used for ejecting ink. , A step of exposing the photosensitive resin, which contains a coupling agent for improving the adhesive force with the substrate, and is disposed on the substrate, to form an ink passage, and unnecessary for forming the ink passage And a step of performing a process for completing the reaction between the coupling agent in the photosensitive resin and the substrate with respect to the exposed photosensitive resin. And a method for manufacturing an inkjet recording head.