JP2010023525A - Inkjet head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid repellent material of an inkjet head which can bring about high image recording quality and to provide high liquid repellency, high durability to wiping off (maintaining high liquid repellency), easiness of wiping off, and high adhesion to a nozzle material at the same time. <P>SOLUTION: The inkjet head provided with a nozzle surface having liquid repellency is manufactured. The nozzle surface includes a condensation product prepared from a hydrolyzable silane compound having a fluorine containing group, and a hydrolyzable silane compound having a cation-polymerizable group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a liquid repellent process on the surface of a nozzle in an inkjet head.

  Recently, in order to further advance the recording characteristics in an ink jet recording system, technological developments aiming to improve the performance of smaller droplets, higher driving frequency and more nozzles are continuing. Image recording is performed by ejecting liquid as small droplets that adhere to a recording medium, typically paper, from an ejection opening.

  In this field, the importance of surface treatment is increasing in order to maintain the injection performance by always keeping the injection opening surface (the discharge opening is the opening surface) in the same state.

  Further, in order to maintain the state of the surface of the ejection opening in the ink jet head, it is common to periodically wipe the ink remaining on the surface with, for example, a rubber blade. Liquid repellent materials are required for easy wiping and wiping durability.

  In many cases, since the ink used in the ink jet head is not neutral, it is also necessary that the liquid repellent material has durability against the ink and adhesion strength to the nozzle.

  Furthermore, in recent years, in order to obtain a high-quality image, the nozzle needs a precise nozzle structure. Therefore, it is also necessary that the liquid repellent material has a photosensitive characteristic corresponding to pattern formation by photolithography.

  The present invention utilizes a hydrolyzable silane compound having a fluorine-containing group for liquid repellent finishing on the surface of a nozzle.

  The following official report is given as a conventional example using a hydrolyzable silane compound having a fluorine-containing group.

  Japanese Patent Laid-Open Nos. 06-171094 and 06-210857 disclose a method of performing a so-called silane coupling process on a nozzle surface in which an oxide particle layer is formed in advance using a hydrolyzable silane compound having a fluorine-containing group. Is shown.

  However, with the above method, sufficient wiping durability cannot be obtained. Furthermore, it is difficult to impart photosensitive characteristics to the liquid repellent material with the above system.

  US Pat. No. 5,910,372, European Patent No. 778869, and Japanese Patent Application Laid-Open No. 10-505870 disclose condensation comprising a hydrolyzable silane compound having a fluorine-containing group and a silane compound having a substituent that reacts with a substrate. It shows the potential for use in coatings and ink jet nozzles comprising the composition. Examples of substituents that react with the substrate include amino groups and carboxyl groups.

  In the above composition, crosslinking of the liquid repellent layer means formation of a siloxane network by hydrolysis and condensation.

  In general, crosslinked siloxane networks are affected by the inks used in ink jet recording systems, especially when the ink is not a neutral aqueous solution. The siloxane network is again hydrolyzed and the liquid repellency is reduced. Furthermore, the photosensitive properties of the composition are not mentioned.

  US Pat. No. 6,283,578 and European Patent No. 816094 disclose surface treatment for liquid repellency with a silane compound having a radical photopolymerizable group. In this composition, cross-linking of the liquid repellent layer means formation of a siloxane network and radical photopolymerization. Photoradical polymerization corresponds to photosensitive properties. Liquid repellency is derived from the siloxane network itself.

  Furthermore, the above specification refers to a coating of a hydrolyzable silane compound having a fluorine-containing group as the second layer on the siloxane structure when high liquid repellency is required.

  However, in the above two-layer structure, the hydrolyzable silane compound layer having a fluorine-containing group itself has no photosensitivity, so that no photosensitivity can be imparted.

  The Journal of Applied Physics, Journal of Applied Physics, Vol. 41 (2002), pages 3896 to 3901, includes a specific arylsilane and a fluorine-containing group as a liquid repellent layer exhibiting excellent durability in alkaline inks. Condensation products with hydrolyzable silane compounds having However, with this composition, it is difficult to add photosensitive characteristics.

  Further, the present applicant has proposed the methods shown in Japanese Patent Laid-Open Nos. 04-10940 to 04-10942 as high-quality IJ recording methods.

  Further, the present applicant has disclosed a method disclosed in Japanese Patent Application Laid-Open No. 06-286149 as an optimum method for manufacturing an IJ head for the above-mentioned IJ recording method disclosed in Japanese Patent Application Laid-Open Nos. 04-10940 to 04-10942. Proposed.

  In the above method, a photosensitive material is used for the nozzle portion, and a precise nozzle structure is realized by a photolithography technique.

  The liquid repellent material shown here in the above conventional example is difficult to impart photosensitive characteristics, and it has been difficult to use it for nozzle production using photolithography technology.

  On the other hand, the present applicant has published in Japanese Patent Laid-Open Nos. H11-322896, 11-335440, and 2000-322896 as liquid repellent materials having photosensitive characteristics applicable to the above-mentioned Japanese Patent Laid-Open No. 06-286149. Suggested materials.

  The above liquid repellent material is excellent in terms of photosensitivity, high liquid repellency and adhesion with the nozzle material, etc., but because it is necessary to output a higher quality image at a higher speed, higher liquid repellency, There is a need for durability against wiping (maintaining high liquid repellency) and ease of wiping.

  US Pat. No. 5,644,014, European Patent No. 587667 and Japanese Patent No. 3306442 show liquid repellent materials using hydrolyzable silane compounds having fluorine-containing groups.

  Although the above materials exhibit photocurability using photoradical polymerization, they do not mention the production of patterns using photolithography techniques or the use in inkjet heads.

Japanese Patent Laid-Open No. 06-171094 Japanese Patent Laid-Open No. 06-210857 US Pat. No. 5,910,372 European Patent No. 778869 Japanese National Patent Publication No. 10-505870 US Pat. No. 6,283,578 EP 816094 Specification Japanese Patent Laid-Open No. 04-10940 Japanese Patent Laid-Open No. 04-10942 Japanese Patent Laid-Open No. 06-286149 Japanese Patent Laid-Open No. H11-322896 JP-A-11-335440 JP 2000-322896 A US Pat. No. 5,644,014 European Patent No. 587667 Japanese Patent No. 3306442

Journal of Applied Physics, Journal of Applied Physics, Volume 41 (2002), pages 3896-3901

  The present invention is made in consideration of the above-mentioned many points, and simultaneously provides high liquid repellency, high durability against wiping (maintaining high liquid repellency), ease of wiping and high adhesion to the nozzle material. In order to achieve this, and to provide a liquid repellent material for an inkjet head that realizes high-quality image recording.

  Furthermore, the present invention provides a method for producing an ink jet head for high-quality image recording by imparting photosensitive properties to the liquid repellent material.

  Designed to achieve the above object, the present invention is characterized in that the injection surface has liquid repellency and the injection opening surface has a hydrolyzable silane compound having a fluorine-containing group and a cationically polymerizable group. An ink jet head made of a condensation product containing a silane compound.

Another invention designed to achieve the above object is:
A method for producing an ink jet head comprising producing a nozzle surface having liquid repellency by simultaneously forming a photopolymerizable liquid repellent layer on a photopolymerizable resin layer and then simultaneously performing pattern exposure and development. The photopolymerizable liquid repellent layer produces an ink jet head containing a condensation product of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group. Is the method.

further,
Producing an ink passage pattern with a soluble resin material on the ink ejection pressure generating element on the substrate;
Producing a polymerizable coating resin layer on the soluble resin material pattern;
Producing a liquid repellent layer on the coating resin layer;
Creating an ink ejection opening by removing the coating resin layer and the liquid repellent layer above the ink ejection pressure generating element;
A method for manufacturing an inkjet head, comprising dissolving the soluble resin material pattern,
A method in which the liquid repellent layer contains a condensation product of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group is preferable.

  According to the present invention, it is made in consideration of the above-mentioned many points, and has high liquid repellency, high durability against wiping (maintaining high liquid repellency), easy wiping and high adhesion to the nozzle material. It is possible to provide a liquid repellent material for an ink jet head that is provided simultaneously and that realizes high-quality image recording.

  Furthermore, according to the present invention, a photosensitive property can be imparted to the liquid repellent material, and an ink jet head manufacturing method for high quality image recording can be provided.

1A to 1D are diagrams illustrating an example of a method for manufacturing an inkjet head according to the present invention. 2A to 2D are diagrams showing another example of the method of manufacturing the ink jet head according to the present invention. 3A to 3D are views showing still another example of the method for manufacturing an ink jet head according to the present invention. 3E to 3G are views showing still another example of the method of manufacturing the ink jet head according to the present invention. 3H to 3K are views showing still another example of the method of manufacturing the ink jet head according to the present invention.

  The present invention will be described in detail. As described above, it is known to use a hydrolyzable silane compound having a fluorine-containing group for a liquid repellent layer of an inkjet head.

  However, when a hydrolyzable silane compound having a fluorine-containing group is reacted with the nozzle surface by a hydrolysis reaction to produce a substantially monomolecular liquid-repellent layer, the liquid-repellent layer is removed by a wiping operation to clean the nozzle surface. Peels off, and the liquid repellency of the nozzle surface cannot be maintained. In general, since the liquid repellent layer is always in contact with a non-neutral recording liquid, the liquid repellency deteriorates due to a hydrolysis reaction. In addition, it has been difficult to impart photosensitive characteristics in order to produce a high-precision nozzle structure. As a result of intensive studies, the present inventors can solve the above problem by preparing a liquid repellent layer with a condensation product of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzed compound having a cationic polymerizable group. I found.

  According to the configuration of the liquid repellent layer of the present invention, the cured material has a siloxane skeleton (inorganic skeleton) generated from the hydrolyzable silane and a skeleton (organic skeleton, epoxy group) obtained by curing the cationic polymerizable group. When used, it has an ether bond). As a result, the cured material becomes a so-called organic-inorganic hybrid cured material, and the durability against wiping and its recording liquid is dramatically improved. That is, since the liquid repellent layer of the present invention has an organic skeleton, it is considered that the strength as a film is improved as compared with a liquid repellent layer produced by using only a siloxane skeleton.

  Further, since the organic skeleton is generated by cationic polymerization (generally forming an ether bond), the skeleton of the liquid repellent layer is hardly hydrolyzed even if the recording liquid is not neutral. Therefore, very excellent recording liquid resistance can be obtained. Here, when the organic skeleton is generated by radical polymerization, many radical polymerizable groups represented by methacryloxy groups contain ester bonds rather weak against hydrolysis, which is undesirable in terms of recording liquid resistance. There is. In the present invention, the liquid repellent layer formed of an organic skeleton by cation polymerization and a siloxane skeleton also reduces rehydrolysis of the siloxane skeleton, contributing to a surprising improvement in recording liquid resistance.

  Furthermore, according to the present invention, the formation of a siloxane skeleton and an organic skeleton by cationic polymerization when the liquid repellent layer is cured contributes to the formation of chemical bonds with the nozzle surface and the improvement of adhesion to the nozzle surface. To do. In particular, it is particularly desirable from the viewpoint of adhesive properties to simultaneously cure the liquid repellent layer and the nozzle layer after forming the liquid repellent layer on the cationic polymerizable nozzle layer. Furthermore, in the liquid repellent layer of the present invention, by including a cationic photopolymerization initiator in the liquid repellent layer, an acid is generated by light irradiation, and the liquid repellent layer is cured by polymerization of a cationic polymerizable group. enable. Normally, the curing (hydrolysis and condensation reaction) of the hydrolyzable silane compound is performed by heat, but the hydrolysis reaction is accelerated by the presence of an acid, and a strong skeleton can be produced. Furthermore, in the above embodiment, it is possible to impart photosensitivity to the liquid repellent layer, and a precise nozzle structure can be produced. Further, in the embodiment in which the liquid repellent layer and the nozzle layer are simultaneously cured after the liquid repellent layer is prepared on the cationic polymerizable nozzle layer, it is natural that both the liquid repellent layer and the nozzle layer have cationic light. If a polymerization initiator is included, both layers can be cured. The present inventors have found that the liquid repellent layer can be cured by cationic polymerization even in a surprising embodiment in which the cationic photopolymerization initiator is not included in the liquid repellent layer but only in the nozzle layer. This phenomenon is considered because the acid generated from the cationic photopolymerization initiator of the nozzle layer by light irradiation can diffuse into the liquid repellent layer, and the liquid repellent layer can also be cured. As an advantage of the above embodiment, since the liquid repellent layer is cured only at the portion where the nozzle layer is cured, the conditions for forming the nozzle pattern do not depend on the liquid repellent layer. That is, it is not necessary to consider the difference in photosensitivity between the liquid repellent layer and the nozzle layer. In general, it is difficult to perfectly match the photosensitive properties of two or more photosensitive resin layers.

  Next, the constituent materials of the liquid repellent layer used in the present invention will be described in detail.

  As a hydrolyzable silane compound having a fluorine-containing group, the general formula (1)

An alkoxysilane having a fluorinated alkyl group represented by the formula is preferably used.

In the above formulas, R _f is a non-hydrolyzable substituent having 30 fluorine atoms from one bonded to a carbon atom, R represents a non-hydrolyzable substituent, X is a hydrolyzable substituent, b is 0 To an integer of 2, preferably 0 or 1, in particular 0.

A particular preferred substituent R _f is CF ₃ (CF ₂ ) _n —Z—, wherein n and Z are the following general formula (4)

In which X is as defined in general formula (1), preferably methoxy or ethoxy, Z is a divalent organic group, n is 0 to 20, preferably 3 to 15, more preferably Is an integer from 5 to 10. Preferably, Z contains no more than 10 carbon atoms, more preferably no more than 6 carbon atoms, such as methylene, ethylene, propylene, butylene, methyleneoxy, ethyleneoxy, propyleneoxy and butyleneoxy. A divalent alkylene or alkyleneoxy group having Most preferred is ethylene.

Examples of compound 4 include the following compounds:
_{CF 3 -C 2 H 4 -SiX 3} ;
_{C 2 F 5 -C 2 H 4} -SiX 3;
_{C 4 F 9 -C 2 H 4} -SiX 3;
_{C 6 F 13 -C 2 H 4} -SiX 3;
_{C 8 F 17 -C 2 H 4} -SiX 3;
_{C 10 F 21 -C 2 H 4} -SiX 3;
However, the present invention is not limited to the following compounds. X is a methoxy group or an ethoxy group.

  In the above, the condensation product is prepared using at least two hydrolyzable silanes having fluorine-containing groups, each having a different number of fluorine atoms.

For example, C ₆ F ₁₃ —C ₂ H ₄ —SiX ₃ , C ₈ F ₁₇ —C ₂ H ₄ —SiX ₃ and C ₁₀ F ₂₁ —C ₂ H ₄ —SiX ₃ are used simultaneously. The fluorine-containing group tends to be arranged on the surface of the liquid repellent layer. At this time, in the presence of fluoroalkyl groups of different lengths, the fluoride concentration on the surface is higher than when all the fluoroalkyl groups have the same length. It has been found that wiping resistance and recording liquid resistance are improved. Although the reason for this phenomenon is not clear, the fluoroalkyl group has a linear shape and has an optimal conformation on the surface against the repulsive force of fluorine atoms with high electron density, so that the fluoroalkyl group of different lengths Can exist at their own higher density.

  Next, examples of the silane compound having a cationically polymerizable group include the following general formula (2):

Shown in

In the above formula, R _C is a non-hydrolyzable substituent having a cationic polymerizable group, R is a non-hydrolyzable substituent, X is a hydrolyzable substituent, and b is an integer of 0 to 2.

  As the cationically polymerizable organic group, a cyclic ether group represented by an epoxy group, an oxetane group, a vinyl ether group, or the like can be used. From the viewpoints of availability and reaction control, an epoxy group is preferred.

  More specifically, the following compounds are preferred as examples. Glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, epoxycyclohexylethyltrimethoxysilane, epoxycyclohexylethyltriethoxysilane and the like.

  The present invention is not limited to the above compounds.

  In the present invention, the liquid repellent layer comprises a cured condensation product containing a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group. More preferably, the cured condensation product contains an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound in addition to the hydrolyzable silane compound having a fluorine-containing group and the hydrolyzable silane compound having a cationic polymerizable group. Including. The alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound is useful for controlling the physical properties of the liquid repellent layer.

  Examples of the alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compounds are represented by the following general formula (3)

Shown in

R _a is a nonhydrolyzable substituent selected from substituted or unsubstituted alkyl and substituted or unsubstituted aryl, X is a hydrolyzable substituent, and a is an integer of 0 to 3. In particular, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, propyl Examples include triethoxysilane, propyltripropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane. The present invention is not limited to the above compounds.

  Composition of condensation product, that is, hydrolyzable silane compound having fluorine-containing group which is a component of the present invention, hydrolyzable silane compound having cationic polymerizable group and alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane The combination ratio of the compounds is appropriately determined depending on the usage. The addition amount of the hydrolyzable silane compound having a fluorine-containing group is 0.5 to 20 mol%, preferably 1 to 10 mol%. When the addition amount is lower than this, sufficient liquid repellency cannot be obtained, and when the addition amount is higher than this, a uniform liquid repellent layer cannot be obtained. If the surface uniformity of the liquid repellent layer is not sufficient, light is scattered on the surface of the liquid repellent layer. It is particularly undesirable when the liquid repellent layer has photosensitivity.

  Furthermore, the combination ratio of the hydrolyzable silane compound having the cationic polymerizable group and the alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound has a desirable range of 10: 1 to 1:10.

  Generally, it is desirable that the liquid repellent layer of an inkjet head has a flat surface with almost no unevenness. The liquid repellent layer having irregularities exhibits high liquid repellency (high advance contact angle or high static contact angle) with respect to the recording liquid droplets. However, when the liquid repellent layer is rubbed with the recording liquid in a wiping operation or the like, the recording liquid remains in the concave portion, and as a result, the liquid repellency of the liquid repellent layer may be impaired. In an embodiment in which the recording liquid contains pigment, i.e., colorant particles, this phenomenon is significant because the colorant particles enter and adhere to the concave portions. Therefore, the surface roughness Ra indicating the unevenness of the liquid repellent layer is preferably less than 5.0 nm, and Ra is particularly preferably less than 1.0 nm. In the present invention, producing a liquid repellent layer having a flat surface controls the amount of hydrolyzable silane compound having a fluorine-containing group, and includes an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound. This is achieved by appropriately controlling the amount.

  The liquid repellent layer of the present invention comprises the hydrolyzable silane compound having a fluorine-containing group, the hydrolyzable silane compound having the cationic polymerizable group, and, if necessary, an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane. It is made on the nozzle by curing the condensation product of the compound.

  The hydrolyzable condensation product includes a hydrolyzable silane compound having a fluorine-containing group, the hydrolyzable silane compound having a cationic polymerizable group, and, if necessary, an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound. Is prepared by carrying out the hydrolysis reaction in the presence of water.

  The degree of condensation of the product can be appropriately controlled by the temperature, pH, etc. of the condensation reaction. Furthermore, it is possible to control the degree of condensation as a result of the hydrolysis reaction using a metal alkoxide as a catalyst for the hydrolysis reaction. As the metal alkoxide, aluminum alkoxide, titanium alkoxide, zirconium alkoxide, and complexes thereof (acetylacetone complex and the like) are preferable.

  Furthermore, as the cationic photopolymerization initiator, onium salts, borates, compounds having an imide structure, compounds having a triazine structure, azo compounds or peroxides are referred to. An aromatic sulfonium salt or an aromatic iodonium salt is desirable because of sensitivity and stability.

  Next, an example of an inkjet head having the liquid repellent layer of the present invention will be described.

  1A, 1 </ b> B, 1 </ b> C, and 1 </ b> D of FIG. 1 are conceptual diagrams illustrating a method for manufacturing an inkjet head of the present invention.

  First, 1A in FIG. 1 shows that the liquid repellent layer 11 is formed on the nozzle plate 12 of a resin or SUS plate.

  Prepared by performing hydrolysis reaction of hydrolyzable silane compound having fluorine-containing group, hydrolyzable silane compound having cationic polymerizable group and, if necessary, alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound The liquid containing the condensation product is sprayed, dipped or spin coated, and then cured by heat treatment or light irradiation to provide the liquid repellent layer 11. The thickness of the liquid repellent layer 11 is appropriately determined depending on the shape of use, and is preferably in the range of about 0.1 to 2 micrometers. Next, an ink ejection port is prepared by a machining technique such as excimer laser processing, pulse laser processing, and electric discharge processing on a nozzle plate having a liquid repellent layer formed thereon (1B in FIG. 1).

  It goes without saying that the liquid repellent layer may be cured after the ink ejection port 13 is produced. Further, a protective film or the like may be appropriately disposed on the liquid repellent layer when processing the ink ejection opening.

  The above technique is a desirable embodiment because the nozzle plate and the liquid repellent layer can be processed together, so that the liquid repellent material does not enter the ink ejection port.

  Next, a substrate 14 (1C in FIG. 1) including the ink ejection pressure generating element 15 and the passage member 16 is prepared. The ink jet head is completed by adhering the substrate 14 and the nozzle plate including the ink ejection openings with an adhesive layer if necessary.

  Furthermore, when using a photocurable material as a nozzle plate by the said method, it is also possible to produce a nozzle plate as follows.

  As shown in 2A of FIG. 2, the nozzle material 21 is produced on the base member 22. Next, it is prepared by performing a hydrolysis reaction of a hydrolyzable silane compound having a fluorine-containing group, a hydrolyzable silane compound having a cationic polymerizable group, and if necessary, an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound. By applying a liquid containing the hydrolyzable condensation product, a liquid repellent layer 23 is produced on the nozzle material 23 (2B in FIG. 2). As shown in 2C of FIG. 2, the nozzle material 23 and the liquid repellent layer 27 are cured using pattern exposure, and the uncured portion is removed by development processing (2D in FIG. 2). After producing the nozzle having the liquid repellent layer, it is appropriately peeled from the base member. Next, a substrate including an ink ejection pressure generating element and a passage member is prepared. An ink jet head is completed by adhering a substrate and a nozzle plate including an ink ejection port, if necessary, via an adhesive layer.

  Next, an embodiment of the present invention applied to a method for producing an ink jet head described in JP-A-06-286149 will be described.

The manufacturing method of the inkjet head is as follows:
Producing an ink passage pattern with a soluble resin material on the substrate on which the ink ejection pressure generating element is produced;
Producing a coating resin layer by applying a polymerizable coating resin on the soluble resin material layer as an ink passage wall;
Creating an ink ejection port in the coating resin layer and the liquid repellent layer above the ink ejection pressure generating element;
Dissolving the soluble resin material layer;
Including
The liquid repellent layer contains a cured condensation product of a hydrolyzable silane compound having a fluorine-containing group and the hydrolyzable silane compound having a cationic polymerizable group.

  This will be described below using a general conceptual diagram.

  3A is a perspective view of the substrate 31 on which the ink ejection pressure generating element 32 is formed. 3B of FIG. 3 is a 3B-3B cross-sectional view of 3A of FIG. 3C in FIG. 3 is a view of a substrate on which the ink flow path pattern 33 is made of the soluble resin material. Even in the ink passage pattern on which the nozzle material layer is formed, a positive resist, particularly a photodegradable positive resist having a relatively high molecular weight is preferably used in order to avoid the collapse thereof.

  Next, 3D of FIG. 3 shows that the coating resin layer 34 is formed on the ink passage pattern.

  The coating resin layer is a material that is polymerized by light irradiation or heat treatment, and a cationic photopolymerizable resin is particularly suitable as the coating resin layer. 3E in FIG. 4 indicates that a liquid repellent layer 35 is further formed on the coating resin layer.

  The coating resin layer and the liquid repellent layer can be appropriately prepared by spin coating, direct application, or the like. In particular, direct coating is suitably used for the production of the liquid repellent layer. Although the coating resin layer contains a cation initiator as an indispensable component, as described above, the liquid repellent layer may not contain a cation initiator. The liquid repellent layer can be cured by an acid generated when the coating resin layer is cured. Next, the injection port 36 is produced by pattern exposure through a mask shown in 3F of FIG. 4 and development shown in 3G of FIG. Furthermore, by appropriately setting the mask pattern and exposure conditions, only the liquid repellent layer can be partially removed except for the portion where the injection port is formed. That is, when the mask pattern is less than the limit, only the liquid repellent layer is partially removed. The marginal resolution means a pattern size in which the coating resin layer is not developed to the substrate (3H and 3I in FIG. 5).

  As described above, the liquid repellent layer of the present invention has high liquid repellency and wiping resistance. Therefore, when the wiping operation is executed, the droplet of the recording liquid to be removed may roll and be drawn into the ejection port. As a result, a small recording droplet may not be ejected.

  Japanese Patent Laid-Open No. 06-210859 has proposed to provide a liquid repellent area and a non-liquid repellent area on the nozzle surface in order to prevent this phenomenon. As described above, the present invention can easily produce a pattern that does not partially exist in the liquid repellent layer, and can prevent a situation where ink is not ejected.

  Next, the ink supply opening 37 is appropriately formed on the substrate (3J in FIG. 5), and the ink passage pattern 33 is dissolved (3K in FIG. 5). Finally, if necessary, the nozzle material and the photosensitive liquid repellent material are completely cured by heat treatment to complete the ink jet head. In order to show an example, the case where a cationic photopolymerizable material is used as a coating resin layer has been described with reference to the drawings.

  Using a thermosetting cationic polymer material as the coating resin layer, after forming the liquid repellent layer, an excimer laser is used instead of pattern exposure, and the coating resin layer and the liquid repellent layer are removed by ablation to produce an injection port. May be.

(Synthesis Example 1)
A hydrolyzable condensation product was synthesized by the following procedure. 28 g (0.1 mol) of glycidylpropyltriethoxysilane, 18 g (0.1 mol) of methyltriethoxysilane, 6.6 g of tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane (0 0.013 mol, equal to 6 mol% of the total amount of hydrolyzable silane compounds), 17.3 grams of water and 37 g of ethanol at room temperature and subsequently refluxed for 24 hours to obtain the hydrolyzable condensation product. Obtained.

  Further, the condensation product was diluted with 2-butanol and ethanol to obtain a nonvolatile content of 7% by weight, thereby obtaining a composition 1 for producing a liquid repellent layer.

  Furthermore, 0.04 g of aromatic sulfonium hexafluoroantimonate (trade name SP170 manufactured by Asahi Denka Kogyo Co., Ltd.) is added to 100 g of Composition 1 as a cationic photopolymerization initiator to produce a liquid repellent layer. Composition 2 was obtained.

(Synthesis Example 2)
Instead of 6.6 grams of tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane of Synthesis Example 1, tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane and heptadecafluoro A hydrolyzable condensation product was obtained using 4.4 grams of a mixture of -1,1,1,2-tetrahydrodecyltriethoxysilane. All other conditions were the same.

  Further, the condensation product was diluted with 2-butanol and ethanol to obtain a non-volatile content of 7% by weight to obtain a composition 3 for producing a liquid repellent layer. Further, 0.04 g of aromatic sulfonium hexafluoroantimonate (trade name SP170 manufactured by Asahi Denka Kogyo Co., Ltd.) is added to 100 g of Composition 3 as a cationic photopolymerization initiator to produce a liquid repellent layer. Composition 4 was obtained.

Example 1
The compositions 2 and 4 were applied to a polyamide film by a roll coating method, and the coating solvent was dried by heating at 90 ° C. for 1 minute to dry the coating solvent.

  Next, the compositions 2 and 4 were cured by exposure using a UV irradiation apparatus and heating at 90 ° C. for 4 minutes. Furthermore, the curing reaction was terminated by heating at 200 ° C. for 1 hour in a heating chamber, and a liquid repellent layer was produced. Next, as an evaluation of liquid repellency, the contact angle with respect to the inkjet ink was measured using an automatic contact angle meter (Kyowa Interface Science, CA-W). Hereinafter, θa means the receding contact angle, and θr means the advancing contact angle. According to the study by the present inventors, it is desirable that the contact angle with respect to the ink, particularly the receding contact angle having a strong influence on the ink removal from the nozzle surface by wiping, is higher. The results are shown in Table 1.

  In the table, BCI-3Bk commercially available from Canon is a neutral pigment ink having a surface tension of about 40 mN / m. BCI-8Bk, also commercially available from Canon, is an alkaline dye ink having a surface tension of about 42 mN / m.

  Next, the polyamide film having the liquid repellent layer formed thereon was immersed in BCI-3Bk and 8Bk inks at a temperature of 60 ° C. for 4 weeks to examine the ink resistance of the liquid repellent layer. The results are shown in Table 2 or 3.

  From the above results, the liquid repellent layer according to the present invention has a very high contact angle with respect to ink, that is, high liquid repellency, and also maintains sufficient liquid repellency even after an immersion test assuming long-term storage. Even when the decomposable condensation product is composed of hydrolyzable silane compounds having two or more fluorinated alkyl groups of different lengths, it has been shown to improve liquid repellency, particularly resistance to alkaline inks.

  By the above method, an ink ejection port was produced by irradiating an excimer laser to a polyamide film having a liquid repellent layer on the surface. Next, as shown in FIGS. 1A, 1B, 1C, and 1D, an ink jet head was obtained by bonding a film onto a substrate having an ink ejection pressure generating element and an ink flow path wall. The printing quality of the inkjet head was high definition.

(Example 2)
In this example, an ink jet head was manufactured by the procedure shown in 3A, 3B, 3C, 3D in FIG. 3 and 3E, 3F, and 3G in FIG.

  First, a silicone substrate having an electrothermal conversion element as an ink ejection pressure generating element is prepared, and a polymethylisopropenyl ketone (ODUR-1010, Tokyo Ohka Kogyo Co., Ltd.) coating film is soluble on this silicone substrate by spin coating. It applied as a resin material layer. Next, after pre-baking at 120 ° C. for 6 minutes, pattern exposure of the ink passage was performed by a mask exposure apparatus UX3000 (Ushio Electric).

  The exposure time was 3 minutes, development was carried out with methyl isobutyl ketone / xylene = 2/1 and rinsed with xylene.

  The polymethyl isopropenyl ketone is a so-called positive resist which is decomposed by UV irradiation and becomes soluble in an organic solvent. In the case of pattern exposure, a pattern of a soluble resin material was formed in a portion that was not exposed to obtain an ink supply passage pattern (3C in FIG. 3). The thickness of the soluble resin material layer after development was 20 micrometers. Next, the coating resin comprising cationic photopolymerization shown in Table 4 was dissolved in a methyl isobutyl ketone / xylene mixture solvent at a concentration of 55% by weight, and spin coating was performed on the ink passage pattern formed by the soluble resin material layer. It was applied and heat treated at 90 ° C. for 4 minutes. By repeating this application and heat treatment three times, the thickness of the coating resin layer on the ink passage pattern was 55 micrometers (3D in FIG. 3).

  Next, the composition 1 comprising the hydrolyzable condensation product of the fluorine-containing silane compound was applied on the coating resin layer by direct application. Next, pre-baking was performed at 90 ° C. for 1 minute, and the layer thickness was 0.5 micrometers. Here, the cationic photopolymerization initiator was not added to the composition 1. Next, using a mask exposure apparatus MPA600 super (Canon), pattern exposure of the ink ejection port was performed (3F in FIG. 4).

  After heating at 90 ° C. for 4 minutes, it was developed with methyl isobutyl ketone (MIBK) / xylene = 2/3 and rinsed with isopropyl alcohol to produce an injection port pattern. Here, the layer of the composition 1 excluding the injection port was cured with the cationic photopolymerization initiator in the coating resin layer, while the injection resin pattern was obtained by curing the coating resin layer. The pattern edge of this pattern was an acute angle (3G in FIG. 4). Next, a mask for producing the ink supply opening was appropriately disposed on the back surface of the substrate, and the ink supply opening was produced by anisotropic etching of the silicone substrate. During the anisotropic etching of silicone, the surface of the substrate on which the nozzle was made was protected by a rubber film. After the anisotropic etching was completed, the rubber film was removed, and the entire surface was again irradiated with ultraviolet light using the UX3000, thereby decomposing the soluble resin material layer forming the ink passage pattern. Next, the ink passage pattern was dissolved by immersing in methyl lactate for 1 hour using ultrasonic waves. Next, in order to completely cure the coating resin layer and the liquid repellent layer, a heating process was performed at 200 ° C. for 1 hour (3K in FIG. 5). Finally, an ink supply member was bonded onto the ink supply opening to complete the ink jet head. The ink jet head obtained by the above method was filled with Canon ink BCI-3Bk to print an image, and a high quality image was obtained. Further, in this ink jet head, the advancing contact angle with respect to the ink BCI-3Bk was 86 degrees and the receding contact angle was 65 degrees, and it was proved that the liquid repellent layer had high liquid repellency. Next, the surface roughness of the liquid repellent layer of the inkjet head was measured with a scanning probe model microscope JSPM-4210 in a contact mode. As a result, the surface roughness index Ra was 0.2 to 0.3 nm (scanning area was 10 μm square), and the liquid repellent layer proved to form a very flat and smooth surface. . Next, a wiping operation was performed 30000 times using a blade of HNBR rubber while ink was sprayed onto the nozzle surface of the inkjet head. After this wiping operation, the same high quality image as before wiping was obtained, and therefore, excellent wiping durability was confirmed. Further, the composition 3 was used as a liquid repellent layer in place of the composition 1, and an ink jet head was completed in the same manner. Even after the above wiping operation was applied, the quality of the printed image did not change as before, and excellent wiping durability was confirmed.

  According to the above results, the liquid repellent layer of the present invention can be applied onto the cationic photopolymerizable nozzle material, and then a high-precision injection port structure can be produced by simultaneous pattern exposure of the nozzle material and the liquid repellent layer. High liquid repellency. Due to the excellent wiping durability, high-quality images can be obtained even after wiping.

Claims (33)

  An inkjet head having a nozzle surface having liquid repellency, wherein the nozzle surface is made of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group. An inkjet head.   The condensation product further comprises a hydrolyzable silane compound having at least one alkyl substituent, a hydrolyzable silane compound having at least one aryl substituent or a hydrolyzate having no non-hydrolyzable substituent. The inkjet head according to claim 1, wherein the inkjet head is made from a decomposable silane compound. The hydrolyzable silane compound having a fluorine-containing group has the general formula (1)

R _f is a non-hydrolyzable substituent having 1 to 30 fluorine atoms bonded to a carbon atom, R is a non-hydrolyzable substituent, X is a hydrolyzable substituent, and b is 0 to 0 The inkjet head according to claim 1, wherein the inkjet head is an integer of 2. The inkjet head according to claim 3, wherein the non-hydrolyzable substituent R _f has at least five fluorine atoms bonded to carbon atoms.   The inkjet head according to claim 3 or 4, wherein the condensation product is made from at least two hydrolyzable silanes having fluorine-containing groups containing different numbers of fluorine atoms in the fluorine-containing group. The hydrolyzable silane compound having a cationically polymerizable group has the general formula (2)

Wherein R _C is a non-hydrolyzable substituent having a cationically polymerizable group, R is a non-hydrolyzable substituent, X is a hydrolyzable substituent, and b is an integer of 0 to 2. The inkjet head in any one of 5-5. The hydrolyzable silane compound having an alkyl substituent, having an aryl substituent, or not having a non-hydrolyzable substituent has the general formula (3)

R _a is a nonhydrolyzable substituent selected from _a substituted or unsubstituted alkyl group and a substituted or unsubstituted aryl group, X is a hydrolyzable substituent, and a is an integer of 0 to 3. 2. An ink jet head according to 2.   The inkjet head according to claim 1, wherein the condensation product further contains a cationic initiator.   The inkjet head according to claim 8, wherein the cationic initiator causes polymerization by light irradiation.   The inkjet head according to claim 1, wherein the cured liquid repellent material constitutes the nozzle surface.   The inkjet head according to any one of claims 1 to 10, wherein the nozzle surface exhibits a surface roughness Ra of 5.0 nm.   The hydrolyzable silane compound having a fluorine-containing group is used in a molar ratio of 0.5 to 20 mol% based on the total amount of hydrolyzable compounds used. Inkjet head. A method for producing an inkjet head comprising: applying a photopolymerizable liquid repellent layer on a photopolymerizable resin layer, and simultaneously performing pattern exposure and development to produce a nozzle surface having liquid repellent characteristics. There,
The photopolymerizable liquid repellent layer includes a condensation product formed from a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group.   The method of manufacturing an ink jet head according to claim 13, wherein the condensation product is further made from an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound.   The method for producing an ink jet head according to claim 13 or 14, wherein the photopolymerizable resin layer is made of a cationic polymerizable resin.   The method for producing an ink jet head according to claim 15, wherein the photopolymerizable resin layer contains a cationic initiator, and the photopolymerizable liquid repellent layer does not contain a cationic initiator.   The manufacturing process is removed together from the photopolymerizable resin layer and the photopolymerizable liquid repellent layer by simultaneous pattern exposure and development on both the photopolymerizable resin layer and the photopolymerizable liquid repellent layer. The method for producing an ink jet head according to claim 13, comprising a step of producing a portion and a portion that is removed only from the photopolymerizable liquid repellent layer.   The method for manufacturing an ink jet head according to claim 17, wherein the portion that is removed only from the photopolymerizable liquid repellent layer is produced by pattern exposure that is less than a limit resolution of the photopolymerizable resin layer. Forming an ink passage pattern with a soluble resin material on the ink injection pressure generating element on the substrate;
Producing a polymerizable coating resin layer on the soluble resin material pattern;
Producing a liquid repellent layer on the coating resin layer;
Producing an ink ejection opening by removing the coating resin layer and the liquid repellent layer above the ink ejection pressure generating element;
Dissolving the soluble resin material pattern;
The liquid repellent layer contains a condensation product formed from a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group. How to do it.   The method of manufacturing an ink jet head according to claim 19, wherein the condensation product is further made from an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound.   21. The method for manufacturing an ink jet head according to claim 19, wherein the polymerizable coating resin layer is a photopolymerizable coating resin layer.   The method for producing an ink jet head according to claim 19, wherein the polymerizable coating resin layer is a cationic polymerizable coating resin layer.   The method for producing an ink jet head according to any one of claims 19 to 22, wherein the polymerizable coating resin contains a solid phase epoxy resin at room temperature.   The method for producing an ink jet head according to any one of claims 19 to 23, wherein the photopolymerizable resin layer contains a cationic initiator, and the photopolymerizable liquid repellent layer does not contain a cationic initiator.   The manufacturing process is removed together from the photopolymerizable resin layer and the photopolymerizable liquid repellent layer by simultaneous pattern exposure and development on both the photopolymerizable resin layer and the photopolymerizable liquid repellent layer. The method for producing an ink jet head according to any one of claims 19 to 24, comprising a step of producing a portion and a portion that is removed only from the photopolymerizable liquid repellent layer.   26. The method of manufacturing an ink jet head according to claim 25, wherein the portion removed only from the photopolymerizable liquid repellent layer is produced by pattern exposure that is less than the limit resolution of the photopolymerizable resin layer. The hydrolyzable silane compound having a fluorine-containing group has the general formula (1)

In expressed, R _f is a non-hydrolyzable substituent, R represents a non-hydrolyzable substituent having 30 fluorine atoms from one bonded to a carbon atom, X is a hydrolyzable substituent, b is from 0 27. A method of manufacturing an ink jet head according to any one of claims 13 to 26, which is an integer of two. 28. The method of manufacturing an ink jet head according to claim 27, wherein the non-hydrolyzable substituent _Rf has at least 5 fluorine atoms bonded to carbon atoms.   29. An ink jet head according to claim 27 or 28, wherein the condensation product is made from at least two hydrolyzable silanes having fluorine-containing groups containing different numbers of fluorine atoms in the fluorine-containing group. how to. The hydrolyzable silane compound having a cationic polymerizable group has the general formula (1)

Wherein R _C is a non-hydrolyzable substituent having a cationically polymerizable group, R is a non-hydrolyzable substituent, X is a hydrolyzable substituent, and b is an integer of 0 to 2. 30. A method for producing the inkjet head according to any one of items 1 to 29. The hydrolyzable silane compound having an alkyl substituent, having an aryl substituent, or having no non-hydrolyzable substituent has the general formula (3)

R _a is a nonhydrolyzable substituent selected from _a substituted or unsubstituted alkyl group and a substituted or unsubstituted aryl group, X is a hydrolyzable substituent, and a is an integer of 0 to 3. 14. A method for producing the ink jet head according to 14.   32. The method of manufacturing an ink jet head according to claim 13, wherein the liquid repellent layer is cured by light irradiation or heat treatment after forming an injection opening by pattern exposure and development.   A liquid repellent material for an ink jet head, comprising a condensation product formed from a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group.

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