JP3501587B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head for generating print droplets used in an inkjet printing system and a method for manufacturing the inkjet head.

[0002]

2. Description of the Related Art An ink jet head applied to an ink jet printing system (liquid jet recording system) generally has a fine discharge port (hereinafter also referred to as an orifice), a liquid flow path communicating with the discharge port, and a liquid flow path. And a liquid ejection energy generation unit disposed in a part thereof.

Such an ink jet head can be manufactured, for example, by the following manufacturing method. That is, first, the element substrate 1 including the liquid ejection energy generation unit
The photosensitive resin layer 2 is formed thereon (see FIG. 1A).

Then, the photosensitive resin layer 2 is patterned into a liquid flow path pattern by photolithography to form a mold (hereinafter referred to as a solid layer) for forming a liquid flow path on the element substrate 1 (see FIG. 1 (b), (c)
reference).

Next, a liquid channel wall forming material 5 made of a curable resin is provided on the element substrate 1 so as to cover the solid layer, and the liquid channel wall forming material 5 is cured (FIG. 1 (d)).
reference).

Next, the solid layer is dissolved and removed using an organic solvent such as a halogen-containing hydrocarbon, a ketone, an ester or an alcohol or an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide to form a liquid flow path 6. (Fig. 1
(See (e)).

By the way, in recent years, further improvement in image quality is desired, and liquid flow paths have been arranged at high density. With the increase in the density of the liquid channels, it is necessary to increase the volume of the liquid chamber so that the ink can be quickly supplied to the respective liquid channels. As a means for increasing the volume of the liquid chamber, the height of the liquid flow path wall forming material of the above method has been increased as compared with the conventional method.

As the liquid flow path wall forming material, a photocurable epoxy resin composition has been conventionally used because of its high adhesive strength, high rigidity during curing, and relatively excellent adhesion. However, as described above, as the height at which the liquid flow path wall forming material is provided becomes higher, appropriate exposure conditions become stricter, and in some cases, insufficient curing of the resin may occur due to insufficient exposure. Therefore, the inventors considered changing the curing type of the epoxy resin composition used for the liquid flow path wall forming material from the photo-curing type to the thermosetting type. Curing agents generally used to make epoxy resins thermosetting include acid anhydrides and amine curing agents.

On the other hand, as the material of the solid layer in the above method, a positive type resist containing naphthoquinonediazide is mainly used. The resist of this system has low heat resistance, and in the curing process of the epoxy resin that is the material for forming the liquid flow path wall, curing of a heat curing type acid anhydride or aromatic amine that can be cured only at a relatively high temperature of 130 to 150 ° C. The agent cannot be used because it deforms the solid layer. Therefore, at present, what can be used as a curing agent for epoxy resins is a so-called room temperature curing type amine curing agent that can be cured at a relatively low temperature. However, an epoxy resin composition using a room temperature curing type curing agent generally has lower chemical resistance than an epoxy resin composition using a heat curing type curing agent.

As described above, since the epoxy resin composition using the room temperature curing type curing agent has relatively low chemical resistance, polar solvents (organic compounds such as ketones, alcohols and esters) are used as a removing solution for the solid layer. When a solvent is used, the liquid flow path wall forming material is very likely to swell. And
The swelling of the liquid flow path wall forming material leads to a longer removal time of the solid layer, which is an obstacle to improving the productivity of the inkjet head.

Further, since the epoxy resin composition generally has a high elasticity, a high stress is accumulated between the liquid flow path wall forming material and the substrate due to the curing shrinkage when the resin is cured. Then, as the swelling amount of the liquid flow path wall forming material increases, the stress further increases, so that the liquid flow path forming material may peel off from the substrate. In particular, in an ink jet head in which the ink flow paths are arranged at a high density, the ink flow paths are miniaturized, so that the solid layer is removed for a long time, so that the above-mentioned swelling problem is likely to be prominent.

By the way, recently, along with a high demand for image recording by a printer to which an ink jet printing system is applied, the performance required for an ink has also become higher, and the ink contains urea as a moisturizing agent. Is becoming popular. Furthermore, in order to improve the water resistance of the recorded matter, a poorly water-soluble dye is used as a coloring material, and an ink is made to contain an alkali salt in order to dissolve the dye.

As described above, when the ink contains urea or an alkali salt, the ink exhibits a relatively high alkalinity, but the high alkali ink causes the liquid flow path wall forming material to swell like the polar solvent. easy. Therefore, in the conventional inkjet head created by the above-described manufacturing method using the highly alkaline ink, the liquid flow path may be deformed due to the swelling by the ink and a desired discharge state may not be obtained, and the liquid flow path wall forming material There is a risk of peeling from the substrate, which is not always sufficient from the viewpoint of the reliability of the inkjet head.

As described above, the above-described method for manufacturing an ink jet head has a technical problem that the amount of swelling of the liquid flow path wall forming material is reduced when a polar solvent or a highly alkaline ink is used as a removing liquid.

[0015]

In view of the problems of the ink jet head produced by the above-mentioned manufacturing method, the inventors have earnestly studied a thermosetting epoxy resin composition as a liquid flow path wall forming material, and in particular, It has been found that the above-mentioned problems can be solved by using a specific curing agent and catalyst when using an epoxy resin as a base.

An object of the present invention is to provide a method of manufacturing an ink jet head using a liquid flow path wall forming material having a low swelling amount even when a polar solvent or a highly alkaline ink as a removing liquid is used.

Another object of the present invention is to provide a method for manufacturing an ink jet head, which can shorten the manufacturing time without the solid layer being removed for a long time even when a polar solvent is used as a removing liquid. .

Another object of the present invention is to provide a method for manufacturing an ink jet head in which the liquid flow path forming material is not likely to peel off from the substrate even when a polar solvent or a highly alkaline ink is used as a removing liquid. .

Another object of the present invention is to provide a method of manufacturing an ink jet head which can obtain a desired ejection state without fear of deformation of a liquid flow path due to swelling even when a highly alkaline ink is used. is there.

[0020]

The above-mentioned problems and objects can be solved and achieved by the present invention described below. That is, the present invention provides a step of preparing an element substrate having a liquid ejection energy generating section, a step of forming a photosensitive resin layer on the element substrate, and patterning the photosensitive resin layer into a liquid flow path pattern. A step of forming a solid layer for forming a liquid channel on the element substrate, and a step of providing a liquid channel wall forming material made of a curable resin on the element substrate so as to cover the solid layer,
A method of manufacturing an inkjet head, comprising: a step of curing the liquid flow path wall forming material; and a step of dissolving and removing the solid layer to form a liquid flow path, wherein the liquid flow path wall forming material is an epoxy resin, Epoxy addition modified aromatic amine hard
Disclosed is an inkjet head manufacturing method, which is an epoxy resin composition containing an agent and a Lewis acid catalyst .

According to the present invention, even when a polar solvent or a highly alkaline ink is used as the removing liquid, there is no risk of the liquid flow path forming material peeling from the substrate or the deformation of the liquid flow path due to swelling, which is desirable. It is possible to obtain an inkjet head capable of ensuring the ejection state.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below in order of steps with reference to the drawings. FIG. 2 is a diagram showing a basic manufacturing process of the present invention. Although the drawing shows an inkjet head having three ejection ports, of course,
The same applies to the case of a high-density multi-array inkjet head having more ejection ports than this.

(1) FIG. 2A is a schematic perspective view of the element substrate in this embodiment. First, in the present embodiment, the element substrate 1 made of glass, ceramic, plastic, metal or the like as shown in FIG.
1 is used. The element substrate 11 is not particularly limited as to its shape and material as long as it can function as a part of the liquid flow path and also as a support for a liquid flow path wall forming material described later. A desired number of ejection energy generation elements 12 such as electrothermal conversion elements or piezoelectric elements are arranged on the element substrate 11 (three in FIG. 2A).

The ejection energy generating element 12 gives ejection energy for ejecting the printing liquid droplets to the ink to print. For example, when an electrothermal conversion element is used as the ejection energy generation element 12, the electrothermal conversion element heats the printing liquid near the element to generate ejection energy.
In addition, a control signal input electrode (not shown) for operating these ejection energy generating elements 12 is connected. Further, in general, various functional layers such as a protective layer are provided on the ejection energy generating element 12 for the purpose of improving the durability of these ejection energy generating elements, but such a functional layer is also provided in the present invention. This is all right.

(2) Next, a photosensitive resin layer is formed on the element substrate 11 including the liquid ejection energy generating element 12. Examples of the method for forming the photosensitive resin layer include a method in which the photosensitive resin is dissolved in a solvent and once coated on a film such as a PET film to form a dry film, which is then transferred onto an element substrate by a laminator. be able to. Further, the coating may be formed by a usual spin coating method, a roll coating method or the like.

As the material of the photosensitive resin layer, a naphthoquinonediazide type positive photosensitive resin is preferably used. Next, pattern exposure is performed on the photosensitive resin layer to form the first solid layer 14 that will be the liquid flow path pattern. In the first solid layer 14, the pattern of the photosensitive resin layer remains where it becomes a liquid flow path (see FIG. 2B).

(3) Next, a second solid layer 15 made of a soluble solder resist is formed on the first solid layer 14 by screen printing or the like in the pattern of the liquid chamber (FIG. 2).
(See (c)).

(4) Next, the first and second solid layers 14,
As shown in FIG. 2D, the liquid flow path wall forming material 16 is further formed on the layer 15. The liquid flow path wall forming material 16 is a structural material of an inkjet head, and therefore is required to have characteristics such as high mechanical strength, heat resistance, adhesion to an element substrate, and resistance to ink liquid. In the present invention, an epoxy resin composition is used to satisfy such characteristics.

This epoxy resin composition is a curable resin composition mainly composed of an epoxy resin as a base and a curing agent, and optionally contains a curing catalyst, a silane coupling agent, and the like. I don't mind. As the base epoxy resin, a polyfunctional epoxy resin having two or more epoxy groups in one molecule is preferably used, and examples thereof include bisphenol A type, bisphenol F type, bisphenol AD type and phenol. Examples thereof include novolac type, cresol novolac type, alicyclic type, aliphatic type, naphthalene skeleton type and biphenyl type epoxy resins.

In the present invention, an epoxy addition-modified aromatic amine curing agent is used as a curing agent in the epoxy resin composition. Since this epoxy addition-modified aromatic amine curing agent can be cured at room temperature, there is no risk of deforming the solid layer during curing of the epoxy resin composition. Further, since the curing shrinkage is relatively small as compared with the conventional amine-based curing agent, the peeling of the substrate due to the accumulation of stress during curing is prevented. Also, since it has excellent water resistance and ink resistance, it can maintain a desired ejection state even when a polar solvent or highly alkaline ink is used as a removing liquid, and provides a highly reliable inkjet head. It is possible to do.

This epoxy addition-modified aromatic amine can be produced by reacting an aromatic amine such as metaphenylenediamine, diaminodiphenylmethane or diaminodiphenylsulfone with an epoxy resin such as glycidyl ether. Such a reaction formula is shown below.

[0032]

[Chemical 1]

As a commercially available product, Fujicure 601
0, 6300 (both are trade names: manufactured by Fuji Kasei Kogyo Co., Ltd.) and the like. Fujicure 6010 is a butyl glycidyl ether adduct of 4,4′-diaminodiphenylmethane.

When the epoxy addition modified aromatic amine curing agent which is the curing agent used in the present invention is used, the swelling amount is small with respect to the highly alkaline ink, but the swelling cannot be substantially eliminated. Therefore, in order to further improve the water resistance and ink resistance of the epoxy resin composition used as the liquid flow path forming material, it is preferable to include a curing catalyst in the epoxy resin composition. As the curing catalyst used in the present invention, it is preferable to use a cationic polymerization catalyst.

The cationic polymerization catalyst can dramatically improve the crosslink density of the cured product and improve the water resistance of the epoxy resin composition. Cationic polymerization type catalysts are generally classified into Bronsted acid generation type and Lewis acid generation type. However, Bronsted acid generation type has amine-based curing because it has a curing inhibition by a substance having a strong basicity (such as a compound containing nitrogen). Cannot be used with agents. Therefore,
The cationic polymerization catalyst used in the present invention is limited to the Lewis acid generating type. Examples of such a Lewis acid generation type curing catalyst include boron trifluoride such as boron trifluoride dibutylamine complex, boron trifluoride aniline complex, boron trifluoride isopropylamine complex, and boron trifluoride benzylamine complex. Mention may be made of amine complexes.

As a method of forming the liquid flow path wall forming material 16, a method of dissolving a resin in a solvent and forming it by a solvent coating method can be mentioned.

(5) Further, the top plate 17 provided with the ink supply port is bonded onto the liquid flow path wall forming material (see FIG. 2 (e)).

(6) Finally, as shown in FIG.
The first and second solid layers 14 and 15 are eluted with an organic solvent such as a halogen-containing hydrocarbon, a ketone, an ester or an alcohol or an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide to form a liquid flow path. .

In the above description, an edge shooter type ink jet head is used, but the present invention is also applicable to a side shooter type ink jet head.

The present invention brings excellent effects in a bubble jet recording head among liquid jet recording. The present invention is also effective as a full-line type recording head capable of simultaneously recording over the entire width of the recording paper, and also as a color recording head in which a plurality of recording heads are integrally or combined.

The recording head according to the present invention is also suitably applied to solid ink that is liquefied at a certain temperature or higher even if the ink is not a liquid. That is, the ink may be in a liquid state when the recording signal is applied.

[0042]

EXAMPLES [Experiment] In order to confirm the effect of the present invention, inkjet heads of Experiments 1 to 10 below were prepared and evaluated. In addition, among the inkjet heads of Experiments 1 to 10, the examples according to the present invention are the inkjet heads of Experiments 6 to 9 .

(Experiment 1) Positive resist: PMER AR-900 (trade name: manufactured by Tokyo Ohka Co., Ltd.) on a silicon substrate provided with an ejection energy generating element composed of an electrothermal converter.
Was applied to a film thickness of 50 μm, and then the positive resist was patterned into a nozzle pattern to form a first solid layer on the substrate. In addition, the soluble solder resist is screen-printed so that it becomes the pattern of the liquid chamber.
A second solid layer was formed with a film thickness of 00 μm. Then, the epoxy resin composition shown in Experiment 1 of Table 1 was formed in a thickness of 150 μm as a liquid flow path wall forming material so as to cover the solid layer on the substrate on which the first and second solid layers were formed, and the epoxy resin composition was formed at a room temperature for 30 minutes.
After standing for 1 hour, the epoxy resin composition was cured by performing heat curing at 130 ° C. for 1 hour. Then, after joining a glass top plate on the liquid flow path wall forming material, a screw (2
-Ethoxyethyl) ether was used to dissolve and remove the first and second solid layers. Then, for drying, thermal curing was performed at 130 ° C. for 1 hour to obtain an inkjet head.

[0044]

[Table 1]

(Experiment 2) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 2 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 3) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 3 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 4) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 4 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 5) Except that the epoxy resin composition described in Experiment 5 of Table 1 was used as the liquid flow path wall forming material, and the curing condition of the liquid flow path wall forming material was 130 ° C. for 2 hours. An inkjet head was obtained in the same manner as in Experiment 1.

(Experiment 6) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 6 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 7) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 7 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 8) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 8 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 9) An ink jet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 9 of Table 1 was used as the liquid flow path wall forming material.

(Experiment 10) Table 1 shows the liquid flow path wall forming material.
An inkjet head was obtained in the same manner as in Experiment 1 except that the epoxy resin composition described in Experiment 10 was used.

A heat cycle test was conducted on the ink jet heads obtained in Experiments 1-10. The conditions of the heat cycle test are −30 ° C. for 2 hours to room temperature for 2 hours.
The time was from 10 to 60 ° C for 2 hours for 10 cycles. After this heat cycle test, each head was observed, and those in which no warp or peeling was found were marked with "O", and those in which warp or peeling was found were marked with "X", and the results are shown in Table 1.

In this heat cycle test, no particular abnormality was found in the ink jet heads obtained in Experiments 1, 2, 6-9. Also, Experiments 3 and 1
In the inkjet head obtained with No. 0, peeling between the substrate and the liquid flow path wall forming material was found. Also, Experiment 5
The desired liquid flow path shape was not obtained in the ink jet head obtained in 1. It is considered that this is because the solid layer was deformed (dissolved) in the heat curing step of the liquid flow path wall forming material. Further, in the inkjet head obtained in Experiment 4, no separation between the substrate and the liquid flow path wall forming material was found, but the head itself was found to be curved (warped). It is considered that this occurred because the curing shrinkage of the liquid flow path forming member was large.

Further, in order to investigate the influence of swelling by ink, an ink immersion test (PCT) was conducted on the ink jet heads obtained in Experiments 1-10. The test conditions are highly alkaline ink (pH 10.7, composition: GLY
10.0, UREA 5.0, IPA 5.0, lithium hydroxide 0.4, ammonium sulfate 0.5) was performed at 120 ° C., 2 atmospheres, and 10 hours. After this ink immersion test, each head was observed, and those with neither peeling nor swelling were seen as "A", peeling was not seen but swelling was seen as "○", peeling was seen. The results are shown in Table 1 with “x” as the one.

In this ink immersion test, Experiments 1 and 2
In the ink jet head obtained in 1., peeling from the substrate was not observed, but swelling was slightly observed. In the inkjet heads obtained in Experiments 6 to 9, neither peeling nor swelling was found. It is considered that this is because the crosslinking density was further improved by containing the curing catalyst. Further, in the inkjet heads obtained in Experiments 3 to 5, peeling from the substrate was observed in all cases. This is because the high flow rate ink made the liquid flow path wall forming material easier to swell, and it is considered that peeling occurred due to the stress applied by the swelling.

Further, test printing was carried out using the above-mentioned highly alkaline ink with the ink jet heads obtained in Experiments 1, 2, 6 to 9, and it was found that no image distortion was observed and the print quality was excellent. Was confirmed. As described above, in each of the examples according to the present invention, it can be seen that an inkjet head with less swelling of the liquid flow path wall forming material and high reliability can be obtained.

[0059]

As described above, according to the present invention, the curing and shrinkage of the liquid flow path forming material of the liquid jet recording head can be prevented at low cost without increasing the number of manufacturing steps, and the hardening and shrinkage of the liquid flow path forming material can be prevented. Since the liquid jet recording head itself does not have deflection and printing defects due to the absence of ink, the modified aromatic amine improves the ink resistance of the liquid flow path forming material and improves the reliability of the head. Play.

Further, by using an epoxy resin composition containing an epoxy addition-modified aromatic amine and a Lewis acid catalyst, the mold material removing liquid resistance of the liquid flow path forming material and the ink resistance are improved, and head productivity and It also has the effect of improving reliability.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing a method of manufacturing a conventional inkjet head.

FIG. 2 is a process explanatory view showing a method for manufacturing an inkjet head of the present invention.

[Explanation of symbols]

1,11 Element substrate (first substrate) 2 Photosensitive resin layer (positive photoresist) 3 masks 4 Resist pattern 5,16 Liquid flow path wall forming material 6 liquid flow paths 12 Discharge energy generating element 14 First solid layer 15 Second solid layer 17 Top plate

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-8440 (JP, A) JP-A-5-330066 (JP, A) JP-A-6-184274 (JP, A) JP-A-3- 296525 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/16 C08G 59/50

Claims (7)

(57) [Claims] 1. A step of preparing an element substrate provided with a liquid ejection energy generating section, a step of forming a photosensitive resin layer on the element substrate, and patterning the photosensitive resin layer into a liquid flow path pattern. A step of forming a solid layer for forming a liquid flow path on the element substrate; a step of providing a liquid flow path wall forming material made of a curable resin on the element substrate so as to cover the solid layer; A method of manufacturing an inkjet head, comprising: a step of curing a flow channel wall forming material; and a step of dissolving and removing the solid layer to form a liquid flow channel, wherein the liquid flow channel wall forming material is an epoxy resin and an epoxy resin. With
A method for producing an inkjet head, which is an epoxy resin composition containing a modified aromatic amine curing agent and a Lewis acid catalyst . Wherein said Lewis acid catalyst is a three-a fluoride-boron-amine complex according to claim 1 Symbol mounting the ink jet head manufacturing method. Wherein the solid layer, the ink-jet head manufacturing method according to claim 1 or 2, wherein consists positive photoresist naphthoquinonediazide-containing. 4. The method of manufacturing an inkjet head according to claim 1, wherein a polar solvent is used as a solution for dissolving and removing the solid layer. 5. The liquid discharge port of the liquid flow path, the ink-jet head manufacturing according to any one of claims 1 is of the full-line type comprising a plurality provided over the recording region of the recording medium 4 Method. Wherein said ejection energy generating section, an ink jet head manufacturing method according to <br/> any one of claims 1 to 5 which is an electrothermal transducer for generating thermal energy. 7. An inkjet head obtained by the method for manufacturing an inkjet head according to claim 1.