JPH1178271A - Planographic printing original plate and production of planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planograpahic printing original plate capable of being formed into a planographic printing plate capable of printing a large number of printed matters free from background staining and sharp in image quality by dry desensitizing treatment and a method for producing the planographic printing plate by using the original plate. SOLUTION: A planographic printing original plate has a layer containing at least anetase type titanium oxide particles and a binder resin on its water- resistant support and the contact angle of the surface of the layer with water is 20 deg. or more and that of the surface of the layer with water after the irradiation with ultraviolet rays is 10 deg. or less. A planographic printing plate is formed by forming a color image on the layer by using an ink jet recording system and irradiating the entire surface of this layer with ultraviolet rays and converting a non-image part to a hydrophilic surface state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor and a method of preparing a lithographic printing plate using the lithographic printing plate precursor. More specifically, the present invention relates to a lithographic printing plate precursor capable of printing a large number of clear printed images without background contamination. And the production of a lithographic printing plate using the same.

[0002]

2. Description of the Related Art Lithographic printing plates currently used mainly in the field of light printing include (1) a water-resistant support,
(2) A direct-printing type master provided with a hydrophilic image-receiving layer, (2) a non-image area after directly making a plate on a water-resistant support provided with an image-receiving layer (lipophilic) containing zinc oxide Is subjected to a desensitizing treatment with a desensitizing solution to form a printing plate. (3) An electrophotographic light-sensitive material having a photoconductive layer containing photoconductive zinc oxide on a water-resistant support is used as an original plate. , The non-image part after image formation,
A printing plate is prepared by desensitizing with a desensitizing solution, and (4) a silver salt photographic original plate in which a silver halide emulsion layer is provided on a water-resistant support.

With the recent development of office equipment and OA, in the field of printing, various methods such as an electrophotographic printer, a thermal transfer printer, and an ink jet printer can be applied to the direct drawing type lithographic printing plate precursor of the above (1). There is a demand for an offset lithographic printing method in which a printing plate is directly formed without performing a specific process for performing plate making (that is, image formation) to form a printing plate. In particular, ink jet recording is a recording method capable of high-speed printing with low noise, and is a recording method that is rapidly spreading recently.

As such an ink jet recording system, there is a so-called electric field control system in which ink is ejected by using an electrostatic attraction, and a so-called drop-on-demand in which ink is ejected by using the vibration pressure of a piezo element. Various types of ink jet recording methods, such as a so-called bubble (thermal) jet method, in which ink is ejected using pressure generated by forming and growing bubbles by high heat, and a bubble (thermal) jet method, have been proposed. With these methods, a highly accurate image can be obtained.

[0005] Conventional direct-drawing lithographic printing plate precursors are provided with a surface layer serving as an image receiving layer on both sides of a support such as paper via a back layer and an intermediate layer. Back layer or intermediate layer is PV
It is composed of a water-soluble resin such as A or starch, a water-dispersible resin such as a synthetic resin emulsion, and a pigment. The image receiving layer is
It is composed of an inorganic pigment, a water-soluble resin and a waterproofing agent. Conventionally, inorganic pigments include kaolin, clay, talc, calcium carbonate, silica, titanium oxide, zinc oxide, barium sulfate, alumina and the like.

As the water-soluble resin, modified PVA such as polyvinyl alcohol (PVA) and carboxy PVA;
Starch and derivatives thereof, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose,
Water-soluble resins such as casein, gelatin, polyvinylpyrrolidone, vinyl acetate-crotonic acid copolymer, and styrene-maleic acid copolymer are mentioned.

Examples of the waterproofing agent include an initial condensate of aminoplasts such as glyoxal, melamine formaldehyde resin, and urea formaldehyde resin, a modified polyamide resin such as a methylolated polyamide resin, and a polyamide.
Polyamine / epichlorohydrin adducts, polyamide epichlorohydrin resins, modified polyamide polyimide resins and the like are mentioned. It is also known that ammonium chloride, a crosslinking catalyst for a silane coupling agent, and the like can be used in combination.

On these conventional direct drawing type lithographic printing original plates,
As an inkjet ink used for forming an image by an inkjet recording method, an aqueous ink using water as a main solvent and an oil-based ink using an organic solvent as a main solvent are generally used. However, the water-based ink has a problem that an image on a plate material is blurred, and the drawing speed is reduced due to slow drying. In order to alleviate such a problem, a method using an oil-based ink using a non-aqueous solvent as a dispersion medium is disclosed in Japanese Patent Application Laid-Open No. Sho 54-117203.
Issue.

However, even in this method, bleeding is observed in the actual image quality of the plate making, bleeding occurs when further printing is performed, and the number of prints is limited to several hundred at most, which is insufficient. In addition, such an ink has a problem that nozzles for ejecting minute ink droplets that enable high-resolution plate-making images are easily clogged. In general, in the ink jet recording method, ink is ejected from a nozzle after passing through a filter. Therefore, various other factors such as clogging of the nozzle and clogging of the filter, or change of the fluidity of the ink over time, etc. This tends to cause abnormal ink ejection.

[0010] The abnormal ink ejection occurs not only in the aqueous ink composition but also in the oil-based ink composition. There have been various proposals to improve such ink ejection abnormalities.For example, in order to prevent ink ejection abnormalities when using an oil-based ink composition, an electric field control type inkjet recording method is described. JP-A-49-50935
As described in Japanese Patent Application Laid-Open Publication No. H05-163, there has been proposed to control the viscosity and specific resistance of the ink composition.
As described in Japanese Patent No. 29808/29, a proposal has been made to control the relative dielectric constant and specific resistance of a solvent used in an ink composition.

As an attempt to prevent clogging of nozzles by oily ink for general ink jet printers, for example, a method of improving the dispersion stability of pigment particles (JP-A-4-25573 and JP-A-5-25413). And Japanese Patent Application Laid-Open No. 5-65443), a method of including a specific compound as an ink composition (Japanese Patent Laid-Open No. 3-796).
No. 77, 3-64377, 4-2023
No. 86, No. 7-109431, etc.). However, when any of them is used for image formation on a lithographic printing plate, none of them can satisfy the printing durability due to insufficient strength of the image at the time of printing.

Further, a method of forming an image on an original plate having an image receiving layer containing zinc oxide by an ink jet method and then desensitizing the non-image area by desensitizing the non-image part to perform printing is performed by using the following method. -The image quality of printed matter is good, and it is possible to print many sheets. However, the complexity of wet processing such as the use of a desensitizing solution in the preparation of a printing plate and the necessity of a liquid containing a desensitizing component similar to the desensitizing solution as a fountain solution during printing is essential. Is mentioned. In addition, since a fountain solution containing the above components is used, depending on the printing ink to be used, it may interact with the components in the printing ink and cause stains on a printed material. There is a problem that the used color printing cannot be performed.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of preparing a lithographic printing plate capable of printing a large number of clear images without any background contamination and without any missing or distorted images. It is. It is another object of the present invention to provide a lithographic printing plate precursor capable of printing a large number of prints of clear image quality without background contamination by dry desensitization treatment. Another object of the present invention is to provide a method of preparing an ink-jet type lithographic printing plate capable of stably performing ink-jet recording even when repeatedly used and preparing a lithographic printing plate having excellent printing durability. Another object of the present invention is to provide a method of producing a lithographic printing plate for electrostatic discharge type ink-jet type plate making using oil-based ink, which enables printing of a large number of clear printed images without image smear without background smear. is there.

[0014]

The above object is achieved by the following constitutions (1) to (7). (1) A layer containing at least anatase-type titanium oxide particles and a binder resin on a water-resistant support, the surface of which has a contact angle with water of 20 ° or more, and after irradiation with ultraviolet light. A lithographic printing plate precursor, wherein the surface has a contact angle with water of 10 degrees or less. (2) The smoothness of the layer surface is 30 (seconds / sec.)
The lithographic printing original plate according to the above (1), which is not less than 10 cc). (3) The lithographic printing original plate as described in (1) or (2) above, wherein the water-resistant support has an intrinsic electric resistance value of at least a portion immediately below the layer is 10 ¹⁰ Ω · cm or less.

(4) A colored image is formed on the image receiving layer of a lithographic printing plate precursor having an image receiving layer containing at least anatase-type titanium oxide particles and a binder resin on a water-resistant support by an ink jet recording method. After the formation, a lithographic printing plate is prepared by irradiating the entire surface of the image receiving layer with ultraviolet light to convert a non-image portion into a state of a hydrophilic surface that does not accept the printing ink to form a lithographic printing plate. Method. (5) Image formation using the inkjet recording method
The method for preparing a lithographic printing plate according to the above (4), wherein the oil-based ink is ejected from the nozzles in the form of droplets to form an image.

(6) The oil-based ink has an electric resistance of 10 ⁹ Ω · c
The solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of 3.5 or more and a dielectric constant of 3.5 or less, and the resin particles are colored or further colored particles are dispersed. The method for preparing a lithographic printing plate according to the above (5), characterized in that: (7) The method according to (1), wherein the particles dispersed in the oil-based ink are particles charged to a positive charge or a negative charge, and the oil-based ink is ejected from a nozzle using an electrostatic field. 5) or the method of preparing a lithographic printing plate according to (6). (8) The water-resistant support according to any one of (5) to (7), wherein at least a portion immediately below the image receiving layer has a specific electric resistance of 10 ¹⁰ Ω · cm or less. How to make a lithographic printing plate.

[0017]

Embodiments of the present invention will be described below in detail. The present invention provides a lithographic printing plate precursor
After forming a colored image by an ink jet recording method, an electrophotographic recording method, a thermal transfer recording method, etc., a lithographic printing plate is characterized in that a lithographic printing plate is obtained by exposing the entire surface to ultraviolet light and converting a non-image portion into hydrophilic to form a lithographic printing plate. The printing plate is excellent in image strength and does not cause printing ink stain on the non-image area after the hydrophilic treatment, and the obtained printing plate can print many clear images.

The lithographic printing original plate used in the present invention will be described below. The image receiving layer provided on the water-resistant support of the present invention contains anatase type titanium oxide and a binder resin as main components. The surface Beck smoothness is 30
(Second / 10 cc) or more is preferable. More preferably, 60
~ 2,000 (sec / 10cc). Here, the Beck smoothness can be measured by a Beck smoothness tester. A Beck smoothness tester is a tester in which a test piece is pressed at a constant pressure (1 kg / cm ² ) on a highly smooth finished circular glass plate with a hole at the center, and a constant amount (10 c
The time required for the air of c) to pass between the glass surface and the test piece is measured. The image receiving layer has a contact angle with water of 20 degrees or more, preferably 30 degrees or more.
It is 100 degrees, more preferably 30 degrees to 80 degrees. By adjusting to this range, the ink image formed by the ink jet recording method or the like is sufficiently adhered to the image receiving layer, and even when used as a printing plate, the image portion does not drop during printing.

Further, upon irradiation with ultraviolet light, the non-image portion has the above-mentioned hydrophobic surface state of 10 ° or less, preferably 5 ° or less, more preferably 0 ° in terms of the contact angle with water. It is characterized by changing. Further, the present invention is characterized in that even when a printing plate having a non-image portion made hydrophilic is left for a long time, its hydrophilic state is sufficiently maintained.

The titanium oxide particles used in the present invention have a crystal form of an anatase type and are photoexcited by irradiation with ultraviolet light.
It is characterized in that the particle surface is hydrophilized to a contact angle with water of 5 degrees or less. For details of the phenomenon that the surface is converted to hydrophilic by light irradiation, see, for example, Toshiya Watanabe, Ceramics, 31 (N
o. 10), 837 (1966) and the like. The average particle size of the anatase type titanium oxide particles is from 5 nm to
It is preferably 500 nm, more preferably 5 to 100
nm. In this range, the surface is made hydrophilic by irradiation with ultraviolet light. The anatase type titanium oxide particles should have at least 30% by weight or more of an anatase type crystal structure in the crystal, and preferably 50% by weight.
That is all.

The particles are commercially available as a powder or as a titania sol dispersion. Examples include Ishihara Sangyo Co., Ltd., Titanium Industry Co., Ltd., Sakai Chemical Co., Ltd., Nippon Aerosil Co., Ltd., Nissan Chemical Industry Co., Ltd. Further, the anatase type titanium oxide particles used in the present invention may contain another metal element or an oxide thereof.
The inclusion includes coating, supporting, or doping on the surface and / or inside of the particles.

As the metal element contained, for example, S
i, Mg, V, Mn, Fe, Sn, Ni, Mo, Ru,
Rh, Re, Os, Cr, Sb, In, Ir, Ta, N
b, Cs, Pd, Pt, Au and the like. Specifically, JP-A-7-228738 and JP-A-7-187677
Nos. 8-81223, 8-257399, 8
No. -283022, No. 9-25123, No. 9-714
37 and 9-70532. The content of the anatase type titanium oxide used in the present invention is 90% by weight or more, preferably 95% by weight or more.

As the binder resin used in the image receiving layer of the present invention, all those known as conventional binder resins can be used. Typical are vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-
Methacrylate copolymer, methacrylate copolymer, acrylate copolymer, vinyl acetate copolymer, polyvinyl butyral, alkyd resin, silicone resin, epoxy resin, epoxy ester resin, polyester resin, etc., and polyvinyl alcohol as a water-soluble polymer compound , Modified polyvinyl alcohol, starch, oxidized starch, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, acrylic acid copolymer, methacrylic acid copolymer, vinylpyrodoline copolymer, polyvinyl ether-maleic anhydride copolymer, polyamide And polyacrylamide. These resins may be used alone or in combination of two or more.

The molecular weight of the binder resin used in the image receiving layer of the present invention is preferably 10 ³ to 10 ⁵ , and more preferably 5 to 5.
× 10 ^{3 to} 5 × 10 ⁵ . The glass transition point of the resin is preferably from -10C to 120C, more preferably from 0C to 90C. The image receiving layer of the present invention may contain other constituent components in addition to the components described above. As other components, inorganic pigment particles other than the anatase type titanium oxide particles of the present invention may be contained. For example, silica, alumina, kaolin, clay, zinc oxide, calcium carbonate,
Examples include barium carbonate, calcium sulfate, barium sulfate, magnesium carbonate, and titanium oxide other than anatase type crystals. These other inorganic pigments are present in an amount not exceeding 40 parts by weight based on the anatase type titanium oxide particles of the present invention. Preferably, it is within 30 parts by weight.

The ratio of pigment / binder resin in the image receiving layer is as follows:
Generally, the binder resin is 8 to 25 parts by weight based on 100 parts by weight of the pigment.
Parts by weight, preferably 10 to 22 parts by weight. Within this range, the effects of the present invention are effectively exhibited, and the film strength is maintained during printing or the high hydrophilicity is maintained during desensitization treatment. In addition, a crosslinking agent may be added to the image receiving layer in order to further improve the film strength. In particular, when a water-soluble resin is used as the binder resin, it is preferable to use a crosslinking agent in combination to cure the film and improve the water resistance. Examples of the crosslinking agent include compounds that are usually used as a crosslinking agent. Specifically, compounds described in Shinzo Yamashita, Tosuke Kaneko, “Handbook of Crosslinking Agents” Taiseisha (1981), edited by The Society of Polymer Science, “Polymer Data Handbook, Basic Edition”, Baifukan (1986), etc. Can be used.

For example, ammonium chloride, metal ions,
Organic peroxides, organic silane compounds (for example, silanes such as vinyltrimethoxysilane, vinyltributoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, etc. Coupling agents, etc.), polyisocyanate compounds (for example, toluylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenylisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, high Molecular polyisocyanate, etc.), polyol compounds (for example, 1,4-butanediol, polyoxypropylene glycol, polyoxyethylene glycol, 1,1,1-trimethylolpropane, etc.), Amine compound (e.g., ethylenediamine, .gamma.-hydroxypropyl ethylenediamine, phenylenediamine, hexamethylenediamine-diamine, N
-Aminoethylpiperazine, modified aliphatic polyamines, etc.), titanate coupling compounds (eg, tetrabutoxytitanate, tetrachloroepoxytitanate, isopropyl tristearoyl titanate, etc.), aluminum coupling compounds (eg, aluminum butyrate, aluminum acetyl acetate) , Aluminum oxide octate, aluminum tris (acetyl acetate), etc.), polyepoxy group-containing compounds and epoxy resins (for example, "New epoxy resin" edited by Hiroshi Kakiuchi)
Compounds described in Shokodo (1985), "Epoxy Resins" edited by Kuniyuki Hashimoto and published by Nikkan Kogyo Shimbun (1969), etc., and melamine resins (for example, "Uria Melamine Resin" edited by Ichiro Miwa and Hideo Matsunaga) Kogyo Shimbun (196
9), poly (meth) acrylate compounds (for example, “Oligomers” edited by Shin Ogawara, Takeo Saegusa, Toshinobu Higashimura, Kodansha (1976), Eizo Omori “Functional acrylic resin” Compounds described in Techno System (1985) and the like.

In the present invention, a reaction accelerator may be added as necessary to accelerate the crosslinking reaction in the image receiving layer. In the case of a reaction mode in which a crosslinking reaction forms a chemical bond between functional groups, for example, organic acids (acetic acid, propionic acid, butyric acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.), phenols (phenol, chlorophenol, Nitrophenol, cyanophenol, bromophenol, naphthol, dichlorophenol, etc.), organometallic compounds (acetylacetonato zirconium salt, acetylacetone zirconium salt, acetylacetocobalt salt, dibutoxytin dilaurate, etc.), dithiocarbamic acid compounds (diethyldithiocarbamate, etc.) ), Tinouram disulfide compounds (such as tetramethyltinouram disulfide), carboxylic anhydrides (phthalic anhydride, maleic anhydride, succinic anhydride, butylsuccinic anhydride,
3,3 ', 4,4'-tetracarboxylic acid benzophenone dianhydride, trimellitic anhydride, etc.).
When the cross-linking reaction is a polymerization reaction mode, a polymerization initiator (a peroxide, an azobis-based compound, or the like) may be used.

The binder resin is preferably thermoset after the application of the image receiving layer composition. In order to carry out thermosetting, for example, the drying conditions are made stricter than the drying conditions at the time of the conventional receiving layer production. For example, it is preferable to set the drying conditions to a high temperature and / or a long time, or to further heat-treat after drying the coating solvent. For example, the treatment is performed at 60 ° C. to 150 ° C. for 5 to 120 minutes. When the above-mentioned reaction accelerator is used in combination, the treatment can be performed under milder conditions. Furthermore, JP-A-4-201387 and JP-A-4-22319.
No. 6, No. 4-319492, No. 5-5807
No. 1, No. 4-353495, No. 5-1195
No. 45, etc., may contain resin particles containing a specific functional group.

When these inorganic pigments or resin particles are used within the above-mentioned usage range, bleeding of the ink image at the time of forming an image of the ink by the ink jet recording method is suppressed, and the non-image portion of the non-image portion due to irradiation with ultraviolet light is suppressed. The printing plate after desensitization (hydrophilicity) suppresses background contamination of printed matter,
Further, the image portion is sufficiently adhered to the image receiving layer, and sufficient printing durability can be obtained without causing image defects even when the number of printed sheets increases. Further, it is preferable because the film strength of the image portion layer of the plate-making printing plate is also improved.

In the image receiving layer, other additives may be used in order to improve various properties such as adhesiveness, film formability and film strength. For example, rosin, petroleum resin, silicone oil, etc., such as polybutene, DOP, DBP, low molecular styrene resin, and low molecular Polyethylene wax, microcrystalline wax, paraffin wax and the like can be added within a range that does not affect the background of the printing plate. The thickness of the image receiving layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.
Range. Within this range, it is possible to print a large number of sheets without background stain on the printed matter.

As the water-resistant support, an aluminum plate,
Bimetal plates such as zinc plate, copper-aluminum plate, copper-stainless plate, chromium-copper plate, etc., and tri-metal plates such as chrome-copper-aluminum plate, chrome-lead-iron plate, chromium-copper-stainless plate, etc. Is 0.1 to 3 mm, especially 0.1 mm.
1 to 1 mm. Moreover, the thickness is 80 μm or more.
Paper, plastic film or metal film-laminated paper or plastic film which has been subjected to a water resistance treatment of 200 μm, and the like can be used. The support provided in the present invention has a surface smoothness on the side adjacent to the image receiving layer of 300 (sec / 10 cc) or more, preferably 90 in Beck smoothness.
It is preferably adjusted to 0 to 3000 (sec / 10 cc), more preferably 1000 to 3000 (sec / 10 cc).
cc).

By regulating the smoothness of the surface of the support on the side adjacent to the image receiving layer to a Beck smoothness of 300 (sec / 10 cc) or more, image reproducibility and printing durability can be further improved. . Such an improvement effect can be obtained even if the smoothness of the image receiving layer surface is the same, and the adhesion between the image portion and the image receiving layer is improved by increasing the smoothness of the support surface. Conceivable. Here, the Beck smoothness can be measured by a Beck smoothness tester in the same manner as described above. What is a Beck smoothness tester?
A test piece is pressed at a constant pressure (1 kg / cm ² ) on a circular glass plate with a hole in the center, which has been finished to a high degree of smoothness. It measures the time required to pass between and.

The highly smooth surface of the water-resistant support thus regulated refers to a surface on which the image receiving layer is directly applied. For example, an under layer and an overcoat layer described later are formed on the support. When provided, it refers to the surface of the underlayer or overcoat layer. As a result, the image receiving layer with the adjusted surface bear as described above is sufficiently retained without receiving the unevenness of the surface of the support, and the image quality can be further improved. As a method for setting the smoothness in the above range, various conventionally known methods can be used. Specifically, a method of adjusting the Beck smoothness of the surface of the support body by a method such as a method of melting and bonding the substrate surface with a resin, a method of strengthening a calendar with a high-smooth heat roller, and the like can be used. .

Further, the present invention provides a lithographic plate used for forming an image on an image receiving layer provided on a water-resistant support by an electrostatic discharge type ink jet method in which an oily ink is discharged by utilizing an electrostatic field. It can be preferably used also as a printing original plate, and the obtained lithographic printing plate can print many clear images. The water-resistant support preferably has conductivity, and at least a portion immediately below the image receiving layer has a specific electric resistance of 10 ¹⁰ Ω · cm or less. More preferably, the entirety of the support is 10 ¹⁰ Ω · cm or less. The above specific electric resistance value is more preferably 10 ⁸
Ω · cm or less, and the value may be infinitely zero.

In order to impart the above-described conductivity to the portion of the support immediately below the image receiving layer, a layer comprising a conductive filler such as carbon black and a binder is provided on a substrate such as paper or film. Examples of the method include coating, attaching a metal foil, and depositing a metal. On the other hand, examples of the support having conductivity as a whole include conductive paper impregnated with sodium chloride and the like, plastic films mixed with a conductive filler such as carbon black, and metal plates such as aluminum.

When the conductivity is in the above range, when a charged ink droplet adheres to the image receiving layer, the charge of the ink droplet is quickly eliminated through the ground plane, so that a clear image without disturbance is generated. Is formed. The measurement of the specific electric resistance (also referred to as the volume specific electric resistance or the specific electric resistance) was performed by a three-terminal method in which a guard electrode was provided based on JlSK-6911.

The conductive water-resistant support provided in the present invention will be described. First, a case where the entire support has conductivity will be described. For example, using conductive base paper impregnated with sodium chloride etc. on the substrate,
It can be obtained by providing a water-resistant conductive layer on the screen. In the present invention, as the base paper used as the base, for example, wood pulp paper, synthetic pulp paper, or a mixed paper of wood pulp paper and synthetic pulp paper can be used as it is. The thickness of the base paper is 80 μm to 200 μm.
m is preferred.

Next, formation of the conductive layer will be described. The formation of the conductive layer is achieved by applying a layer containing a conductive filler and a binder to both sides of the conductive paper. The thickness of the conductive layer applied is preferably 5 μm to 20 μm. Examples of the conductive filler include particulate carbon black, graphite, for example, metal powder such as silver, copper, and nickel, tin oxide powder, flaky aluminum or nickel, fibrous carbon, brass, aluminum, steel, and stainless steel. can give.

On the other hand, as the resin used as the binder, various resins are appropriately selected and used. Specifically, as the hydrophobic resin, for example, acrylic resin, vinyl chloride resin, styrene resin, styrene-butadiene resin, styrene-acrylic resin, urethane resin,
Vinylidene chloride-based resins, vinyl acetate-based resins, etc. are used. Examples of hydrophilic resins include polyvinyl alcohol-based resins, cellulose derivatives, starch and its derivatives, polyacrylamide-based resins, and styrene-maleic anhydride-based copolymers. No.

Another method for forming the conductive layer is to laminate a conductive thin film. As the conductive thin film, for example, a metal foil, a conductive plastic film, or the like can be used. More specifically, an aluminum foil is used as the metal foil laminate, and a polyethylene resin mixed with carbon black is used as the laminate of the conductive plastic film. The aluminum foil may be either hard or soft and has a thickness of 5μ.
m to 20 μm are preferred.

The extrusion laminating method is preferred for laminating a polyethylene resin into which carbon black has been infiltrated.
The extrusion laminating method is a method in which a polyolefin is melted by heat, formed into a film, immediately pressed against base paper, and then cooled and laminated. Various apparatuses are known. The thickness of the laminate layer is preferably from 10 μm to 30 μm. In the case where a plastic film or a metal plate having conductivity is used as the substrate assuming that the whole support has conductivity, the support can be used as it is as long as the water resistance is satisfied.

As the plastic film having conductivity, for example, polypropylene or polyester film mixed with a conductive filler such as carbon fiber or carbon black can be used. As the metal plate, aluminum or the like can be used. The thickness of the substrate is preferably 80 μm to 200 μm. If it is less than 80 μm, the strength as a printing plate is insufficient,
If it exceeds 200 μ, handling properties such as transportability in the drawing apparatus deteriorate.

Next, a structure in which a conductive layer is provided will be described. 80 μm to 20 μm thick as a water-resistant substrate
Paper, a plastic film or a paper laminated with a metal foil, a plastic film or the like which has been subjected to a water resistance treatment of 0 μm can be used. As a method for forming a conductive layer on the substrate, the method described above in the case where the whole support has conductivity can be used. That is, a layer containing a conductive filler and a binder is formed on one surface of the substrate with a thickness of 5 μm.
Apply at m-20 μm. Alternatively, it can be obtained by laminating a metal foil or a plastic film having conductivity.

As a method other than the above, for example, a metal film such as aluminum, tin, palladium, or gold may be provided on a plastic film. As described above, a water-resistant support having a specific electric resistance of 10 ¹⁰ Ω · cm or less can be obtained. In the present invention, a back coat layer (back layer) can be provided on the surface of the support opposite to the image receiving layer for the purpose of preventing curling as described above. The back coat layer has a smoothness of 150 to 700. (Second / 1
0 cc).

Thus, when the printing plate is supplied to the offset printing press, the printing plate is accurately set on the printing press without causing displacement or slippage. An image is formed on the lithographic printing original plate as described above by an ink-jet recording method to obtain a plate-making plate. As an inkjet recording method,
Any of the conventionally known recording methods may be used, but an oil-based ink is preferable in view of the drying and fixing properties of the ink image, the difficulty of clogging the ink, and the like, and an electrostatic discharge type ink jet method which does not easily cause image bleeding is a preferable method.

Next, a description will be given of a method of electrostatic ink jet type plate making using oil-based ink. The oil-based ink used in the present invention preferably has an electric resistance of 10 ⁹ Ω · c.
a non-aqueous solvent having a dielectric constant of not less than m and a dielectric constant of not more than 3.5
At least at room temperature (15 ° C. to 35 ° C.), solid and hydrophobic resin particles are dispersed. By using such a dispersion medium, the electrical resistance of the oil-based ink is properly controlled, and the ink is appropriately ejected by the electric field, thereby improving the image quality. Further, by using the resin as described above, the affinity with the image receiving layer is increased, and good image quality is obtained and printing durability is improved.

The non-aqueous solvent having an electric resistance of 10 ⁹ Ω · cm or more and a dielectric constant of 3.5 or less used in the present invention is preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or There are aromatic hydrocarbons and halogen-substituted forms of these hydrocarbons. For example, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane,
Cyclodecane, benzene, toluene, xylene, mesitylene, isoper E, isoper G, isoper H, isoper L (Isoper; trade name of Exxon), Shelsol 70, Shersol 71 (Shersol; trade name of Shell Oil Co.), Amsco OMS, Amsco 46
0 solvent (Amsco; trade name of Spirits) or the like is used alone or in combination. The upper limit of the electric resistance of such a non-aqueous solvent is about 10 ¹⁶ Ω · cm, and the lower limit of the dielectric constant is about 1.8.

The reason why the electric resistance of the non-aqueous solvent used is within the above-mentioned range is that when the electric resistance is low, the electric resistance of the ink is not appropriate and the ejection of the ink by the electric field is deteriorated. The reason for setting the range is that when the dielectric constant is high, the electric field in the ink is easily relaxed, whereby the ejection of the ink is easily deteriorated.

The resin particles dispersed in the above-mentioned non-aqueous solvent may be hydrophobic resin particles which are solid at a temperature of 35 ° C. or lower and have a good affinity for the non-aqueous solvent. Glass transition point is -5 ° C to 110 ° C or softening point 33 ° C
The resin (P) having a glass transition point of 10 to 100 ° C or a softening point of 38 to 1 ° C is more preferable.
20 ° C., more preferably 15 ° C.
80 ° C or a softening point of 38 ° C to 100 ° C.

By using such a resin having a glass transition point or a softening point, the affinity between the surface of the image receiving layer of the printing plate and the resin particles is increased, and the bonding between the resin particles on the printing plate is reduced. Therefore, the adhesion between the image portion and the image receiving layer is improved, and the printing durability is improved. On the other hand, regardless of whether the glass transition point or the softening point is low or high, the affinity between the surface of the image receiving layer and the resin particles is reduced, and the bonding between the resin particles is weakened. The weight average molecular weight Mw of the resin (P) is 1 × 10 ³ to 1 × 10 ⁵
And preferably 5 × 10 ³ to 8 × 10 ⁵ , more preferably 1 × 10 ^{4 to} 5 × 10 ⁵ .

As such a resin (P), specifically,
Olefin polymers and copolymers (eg, polyethylene, polypropylene, polyisobutylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer,
Ethylene-methacrylate copolymer, ethylene-methacrylic acid copolymer, etc.), vinyl chloride copolymer (for example, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer), vinylidene chloride copolymer, vinyl alkanoate polymer And copolymers, allyl alkanoate polymers and copolymers, polymers and copolymers of styrene and its derivatives (e.g., butadiene-styrene copolymer, isoprene-styrene copolymer, styrene-methacrylate copolymer, styrene Acrylate copolymer), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylate polymer and copolymer, methacrylate polymer and copolymer, itaconate diester polymer Copolymers and copolymers, maleic anhydride copolymers Acrylamide copolymers, methacrylamide copolymers, phenolic resins, alkyd resins,
Polycarbonate resin, ketone resin, polyester resin, silicone resin, amide resin, hydroxyl and carboxyl group-modified polyester resin, butyral resin, polyvinyl acetal resin, urethane resin, rosin resin,
Hydrogenated rosin resin, petroleum resin, hydrogenated petroleum resin, maleic acid resin, terpene resin, hydrogenated terpene resin,
Chroman-indene resin, cyclized rubber-methacrylic acid ester copolymer, cyclized rubber-acrylic acid ester copolymer, copolymer containing a nitrogen-free heterocycle (for example, a furan ring, tetrahydrofuran as a heterocycle) Ring, thiophene ring, dioxane ring, dioxofuran ring,
Lactone ring, benzofuran ring, bensothiophene ring,
1,3-dioxetane ring), epoxy resin and the like.

The content of the dispersed resin particles in the oil-based ink of the present invention is preferably 0.5 to 20% by weight of the whole ink. When the content is small, it becomes difficult to obtain the affinity between the ink and the image receiving layer of the printing original plate, so that a good image cannot be obtained, or problems such as reduced printing durability tend to occur. When the content is large, there are problems such as difficulty in obtaining a uniform dispersion, easy clogging of the ink in the discharge head, and difficulty in obtaining stable ink discharge.

The oil-based ink used in the present invention contains a coloring material as a coloring component together with the above-mentioned dispersed resin particles in order to make the non-image area light-opaque when illuminated by light irradiation after plate making. Preferably. As the coloring material, any pigments and dyes conventionally used in oil-based ink compositions or liquid developers for electrostatography can be used.

As the pigment, those generally used in the technical field of printing can be used irrespective of inorganic pigments and organic pigments. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, pyridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo-based pigment, phthalocyanine-based Pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, and other conventionally known pigments are particularly limited. Can be used without.

As dyes, azo dyes, metal complex dyes,
Naphthol dye, anthraquinone dye, indigo dye,
Oil-soluble dyes such as carbonium dyes, quinone imine dyes, xanthene dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine dyes and metal phthalocyanine dyes are preferred. These pigments and dyes may be used alone or in an appropriate combination, but are preferably contained in the range of 0.01 to 5% by weight based on the whole ink.

These coloring materials may be dispersed in a non-aqueous solvent as dispersed particles themselves in addition to the dispersed resin particles, or may be contained in the dispersed resin particles. In the case of containing, pigments and the like are generally coated with the resin material of the dispersed resin particles to obtain resin-coated particles, and dyes and the like are formed into colored particles by coloring the surface of the dispersed resin particles. General. The resin particles dispersed in the non-aqueous solvent of the present invention, as well as the colored particles and the like, preferably have an average particle size of 0.10 μm to 1 μm. More preferably, it is 0.15 μm to 0.8 μm. This particle size is CA
PA-500 (trade name, manufactured by Horiba, Ltd.).

The non-aqueous dispersion resin particles used in the present invention can be produced by a conventionally known mechanical pulverization method or polymerization granulation method. As a mechanical pulverization method, if necessary, a material to be resin particles are mixed, melted, and directly pulverized with a conventionally known pulverizer through kneading to obtain fine particles,
A method in which a dispersing polymer is used in combination and further dispersed by a wet disperser (for example, a ball mill, a paint shaker, a Keddy mill, a Dyno mill, or the like). And then pulverized and then dispersed in the presence of a dispersing polymer. Specifically, a method for producing a paint or a liquid developer for electrostatography can be used,
These are described, for example, by Kenji Ueki, "Flow and paint dispersion of paints", Kyoritsu Shuppan (1971), "Solomon, Science of Paints", "Paint and SurfaceCoating and Theory".
and Practice ", Yuji Harazaki" Coating Engineering "Asakura Shoten (1971), Yuji Harasaki" Basic Science of Coatings "Maki Shoten (1977), and the like.

As the polymerization granulation method, a conventionally known non-aqueous dispersion polymerization method can be mentioned. Specifically, the latest technology of ultrafine polymer supervised by Soichi Muroi, Chapter 2, CMC plate (I991) Koichi Nakamura, Ed., “Development and Practical Use of Recent Electrophotographic Development Systems and Toner Materials”, Chapter 3, (Nippon Scientific Information Co., Ltd., 1985), KBJ Barrett, “Dispersio
n Polymerization in Organic Media '' John Wiley
(1976).

Usually, a dispersion polymer (PS) is used in combination to stabilize the dispersion of the dispersed particles in a non-aqueous solvent. The dispersed polymer (PS) contains a repeating unit soluble in a non-aqueous solvent as a main component, and has an average molecular weight of preferably 1 × 10 ³ to 1 × 10 ⁶ , more preferably 5 × 10 ^{3 as} a weight average molecular weight Mw. ５5 × 10 ⁵ . Preferred examples of the soluble repeating unit of the dispersion polymer (PS) used in the present invention include a polymerization component represented by the following general formula (I).

[0060]

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In the general formula (I), X ₁ is —COO
Represents-, -OCO- or -O-. R ₁ has ₁ carbon atom
Represents an alkyl group or alkenyl group of 0 to 32, preferably represents an alkyl group or alkenyl group having 10 to 22 carbon atoms, which may be linear or branched, and is preferably unsubstituted. You may have. Specifically, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group,
And linolel groups.

A ¹ and a ² may be the same or different from each other, and are preferably a hydrogen atom, a halogen atom (eg, a chlorine atom, a bromine atom, etc.), a cyano group, and a carbon number of 1 to 3.
Alkyl group (e.g., methyl group, ethyl group, propyl group, etc.), - COO-Z ¹ or -CH ₂ COO-Z ¹ [Z ¹
Is an optionally substituted hydrocarbon group having 22 or less carbon atoms (eg, an alkyl group, an alkenyl group, an aralkyl group,
Alicyclic group, aryl group, etc.).

Specifically, Z ¹ is an alkyl group having 1 to 22 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group,
Octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl, eicosanyl, docosanyl, 2-chloroethyl, 2-bromoethyl, 2-methoxycarbonylethyl, 2-methoxy An alkenyl group having 4 to 18 carbon atoms which may be substituted (for example, 2-methyl-1).
-Propenyl group, 2-butenyl group, 2-pentenyl group,
3-methyl-2-pentenyl group, 1-pentynyl group, 1
-Hexenyl group, 2-hexenyl group, 4-methyl-2-
A hexenyl group, a decenyl group, a dodecenyl group, a tridecenyl group, a hexadecenyl group, an octadecenyl group, a linolel group, etc., and an optionally substituted aralkyl group having 7 to 12 carbon atoms (for example, benzyl group, phenethyl group, 3-phenylpropyl group) , Naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.), carbon number 5
To 8 optionally substituted alicyclic groups (e.g., cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, etc.), and optionally substituted aromatic groups having 6 to 12 carbon atoms (e.g., Phenyl, naphthyl, tolyl, propylphenyl, butylphenyl, octylphenyl, methoxyphenyl, chlorophenyl, bromophenyl, acetylphenyl, methoxycarbonylphenyl, ethoxycarbonylphenyl, propioamidophenyl And the like.

The dispersing polymer (PS) may contain another repeating unit as a copolymer component together with the repeating unit represented by the general formula (I). The other copolymer component may be any compound as long as it is composed of a monomer copolymerizable with the monomer corresponding to the repeating unit of the general formula (I). The proportion of the polymer component represented by the general formula (I) in the dispersed polymer (PS) is preferably at least 50% by weight, more preferably at least 60% by weight.

Specific examples of these dispersed polymers (PS) are disclosed in Japanese Patent Application Nos. 9-16967 and 9-19696.
Nos. 9-21014, 9-21011, 9-
No. 21017 and JP-B-6-40229. However, it is not limited to these. The dispersion polymer (PS) is preferably added in advance during polymerization when the resin (P) particles are produced as an emulsion (latex) or the like. When the dispersing polymer (PS) is used, the amount added is about 0.05 to 4% by weight based on the whole ink.

The dispersed resin particles and colored particles (or coloring material particles) in the oil-based ink of the present invention are preferably positively charged or negatively charged electro-detectable particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately utilizing a technique of a developer for wet electrophotography. Specifically, the aforementioned “Recent development and practical use of electrophotographic development systems and toner materials”, pp. 139-148, edited by the Society of Electrophotographic Engineers, “Basics and Application of Electrophotographic Technology”, pp. 497-505 (Corona 1988)
Annual), Yuji Harasaki “Electrophotography” 16 (No. 2), 44
The test is carried out by using a voltage detection material described on page 1977 and other additives.

Specifically, for example, British Patent No. 8934
No. 29, No. 934038, U.S. Pat. No. 112239
No. 7, No. 3900412, No. 460989,
JP-A-60-179751, JP-A-60-185963
And JP-A-2-13965.

The charge control agent as described above is preferably used in an amount of 0.001 to 1.0 part by weight based on 1000 parts by weight of the carrier liquid as the dispersion medium. If desired, various additives may be added. The upper limit of the total amount of these additives is regulated by the electrical resistance of the oil-based ink. That is, if the electric resistance of the ink from which the dispersed particles have been removed is lower than 10 ⁹ Ω · cm, it becomes difficult to obtain a high-quality continuous tone image. is necessary.

Next, a method of forming an image on the lithographic printing plate precursor (hereinafter, also referred to as “master”) will be described. FIG. 1 shows an example of an apparatus system for performing such a method. The apparatus system shown in FIG. 1 has an ink jet recording apparatus 1 using oil-based ink.

As shown in FIG. 1, first, pattern information of an image (graphics or text) to be formed on the master 2 is transmitted from an information supply source such as the computer 3 through a transmission means such as the bus 4 to the oil-based ink. Is supplied to the ink jet recording apparatus 1 that uses. The ink jet recording head 10 of the recording apparatus 1 stores oil-based ink therein, and when the master 2 passes through the recording apparatus 1, sprays minute droplets of the ink on the master 2 according to the information. Thereby, ink adheres to the master 2 in the pattern. Thus, an image is formed on the master 2 to obtain a plate-making master (plate-making printing original plate).

FIGS. 2 and 3 show examples of the structure of an ink jet recording apparatus as in the apparatus system of FIG. 2 and 3, members common to FIG. 1 are denoted by common reference numerals. FIG. 2 is a schematic configuration diagram showing a main part of such an ink jet recording apparatus, and FIG. 3 is a partial sectional view of a head. The head 10 provided in the inkjet recording apparatus has a slit sandwiched between the upper unit 101 and the lower unit 102 as shown in FIGS. The ejection electrode 10b is arranged in the slit, and the oil ink 11 is filled in the slit.

In the head 10, a voltage is applied to the ejection electrode 10b in accordance with a digital signal of image pattern information. As shown in FIG. 2, a counter electrode 10c is provided so as to face the discharge electrode 10b.
A master 2 is provided above. By applying the voltage, a circuit is formed between the discharge electrode 10b and the counter electrode 10c, and the oil-based ink 11 is discharged from the discharge slit 10a of the head 10 to form an image on the master 2 provided on the counter electrode 10c. Is done.

The tip of the discharge electrode 10b is preferably as narrow as possible to form a high quality image, for example, for printing. For example, the oil-based ink is used for the head 10 in FIG.
And using the ejection electrode 10b having a tip of 20 μm width,
By setting the distance between the ejection electrode 10b and the counter electrode 10c to 1.5 mm and applying a voltage of 3 KV for 0.1 millisecond between the electrodes, a dot of 40 μm can be formed on the master 2.

The original plate obtained as described above is irradiated with ultraviolet light over the entire surface to selectively convert only the non-image areas to a hydrophilic surface state. The image portion is a colored ink image, and retains lipophilicity because it is impermeable to ultraviolet light. As a light source of ultraviolet light to be used, 300 to 450 nm
Any lamp may be used as long as the lamp has the above wavelength. Preferably, those having a wavelength of 350 to 420 nm are effectively used.

For example, there are a mercury lamp, a metal halide lamp, a xenon lamp and the like. Light irradiation is arbitrarily selected as long as the contact angle with water on the surface of the irradiated portion changes to 5 degrees or less, preferably to 0 degrees. For example, an irradiation time of 30 seconds to 5 minutes is preferable. As described above, it is possible to create a printing plate that enables a printed material having a clear print image without background smearing by offset printing. The image forming method of the lithographic printing plate precursor according to the invention is not limited to the ink jet recording method, and a known method such as an electrophotographic recording method and a thermal recording method can be applied.

[0076]

EXAMPLES The present invention will be described in detail with reference to examples below, but the contents of the present invention are not limited to these examples. First, a production example of the ink resin particles (PL) will be described.

Production of Resin Particles (PL-1) 1; Resin Particles: PL-1 A mixed solution of 7 g of a dispersion stabilizing resin (PS-1) having the following structure, 100 g of vinyl acetate and 321 g of Isopar H was stirred under a nitrogen stream. Heated to a temperature of 75 ° C. 2,2'-azobis (isovaleronitrile) as a polymerization initiator
1.5 g (abbreviation AIVN) was added and reacted for 3 hours. Further, 1.0 g of this initiator was added, and after reacting for 3 hours, the temperature was raised to 100 ° C., and the mixture was stirred for 2 hours to distill off unreacted vinyl acetate. After cooling, the mixture was passed through a nylon cloth of 200 mesh, and the resulting white dispersion was a latex having a polymerization degree of 93% and an average particle diameter of 0.42 μm and having good monodispersibility. The particle size was measured with CAPA-500 (manufactured by Horiba, Ltd.). Dispersion stabilizing resin (PS-1)

[0078]

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A part of the white dispersion was centrifuged (rotation speed: 1 × 10 ⁴ rpm, rotation time: 60 minutes), and the precipitated resin particles were collected and dried. The weight average molecular weight (Mw: GPC value in terms of polystyrene) of the resin particles is 2 ×
10 ⁵ , the glass transition point (Tg) was 38 ° C.

Production of resin particles (PL-2); resin particles:
PL-2 [Production of Resin for Stabilizing Dispersion (PS-2)] A mixed solution of 100 g of octadecyl methacrylate, 0.6 g of divinylbenzene and 200 g of toluene was heated to a temperature of 85 ° C. while stirring under a nitrogen stream. 4.0 g of 2,2'-azobis (isobutyronitrile) (abbreviated as AIBN) was added and reacted for 4 hours. Further, A. I. B. N. Was added and reacted for 2 hours. I. B. N. Was added and reacted for 2 hours. After cooling, the mixed solution was reprecipitated in 1.5 l of methanol, and the powder was collected by filtration and dried to obtain 88 g of a white powder. The weight average molecular weight (abbreviated as Mw) of the obtained polymer was 3.8 × 10 ⁴ .

[Production of Resin Particles] The dispersion stabilizing resin P
A mixed solution of 12 g of S-2 and 177 g of Isopar H was heated to 70 ° C. while stirring under a nitrogen stream. 30 g of methyl methacrylate, 70 g of methyl acrylate, 200 g of Isopar G and A.I. I. V. N. 1.0 g
Was added dropwise over 2 hours and stirred as it was for 2 hours.
Further, A.I. I. V. N. And add 85g at a temperature of 85 ° C
And stirred for 3 hours. After cooling, the mixture was passed through a 200-mesh nylon cloth.
Was a latex having an average particle size of 0.38 μm. The particle size was measured with CAPA-500 (manufactured by Horiba, Ltd.).
The Mw of the resin particles was 3 × 10 ⁵ , and the Tg was 28 ° C.

Production of Resin Particles (PL-3): Resin Particles P
L-3 [Production of dispersion stabilizing resin (PS-3)] octadecyl methacrylate 60 g, tridecyl acrylate 40 g,
A mixed solution of 3 g of thioglycolic acid, 5.0 g of divinylbenzene and 200 g of toluene was heated to a temperature of 85 ° C. while stirring under a nitrogen stream. 1,1'-azobis (cyclohexane-1-carbonitrile) (abbreviated to ACH)
N. ) Was added and reacted for 4 hours. Further, A. C.
H. N. Was added and reacted for 2 hours. C. H. N. Was added and reacted for 2 hours. After cooling, 15 g of 2-hydroxyethyl methacrylate was added and the temperature was set at 25C. To this solution, under stirring,
Dicyclohexylcarbodiimide (abbreviated as DCC)
16 g, 4- (N, N-diethylamino) pyridine 0.1.
A mixed solution of 2 g and 40 g of methylene chloride was added dropwise over 1 hour. Further, the reaction was continued for 3 hours to complete the reaction. Next, 10 g of 80% formic acid was added to the reaction mixture, and 1
After stirring for an hour, insolubles were filtered off, and the filtrate was reprecipitated in 2.5 liters of methanol. After collecting the precipitate by filtration, the precipitate was dissolved again in 200 g of toluene, the insoluble matter was filtered off, and the filtrate was reprecipitated in 1 liter of methanol. The precipitate is collected by filtration,
Dried. The yield of the obtained polymer was 70 g and Mw was 4.
It was 5 × 10 ⁴ .

[Production of Resin Particles] The dispersion stabilizing resin P
A mixed solution of 8 g of S-3 and 136 g of Isopar H was heated to a temperature of 60 ° C. while stirring under a nitrogen stream. 50 g of methyl methacrylate, 50 g of ethyl acrylate, 200 g of Isopar G and A.I. I. V. N. 1.0 g
Was added dropwise over 2 hours, and the mixture was stirred for 2 hours. Further, A.I. I. V. N. And add room temperature to 8
The mixture was heated to 0 ° C and stirred for 3 hours. After cooling, the mixture was passed through a 200-mesh nylon cloth.
The latex was 0% and the average particle size was 0.40 μm. The Mw of the resin particles was 3 × 10 ⁵ , and the Tg was 30 ° C.

Production of Resin Particles (PL-4) 4: Resin Particles PL-4 8 g of a dispersion stabilizing resin (PS-4) having the following structure, 95 g of vinyl acetate, 5 g of crotonic acid and 324 g of Isopar H
Was heated to a temperature of 70 ° C. while stirring under a nitrogen stream. As a polymerization initiator, A.I. I. V. N. 1.5 g was added and reacted for 3 hours. Next, the initiator A. I. B. N.
0.8 g was added, the temperature was raised to 80 ° C., and the reaction was performed for 3 hours. I. B. N. 0.5 was added and reacted for 3 hours. After cooling, the mixture was passed through a 200-mesh nylon cloth, and the resulting white dispersion was a latex having a polymerization degree of 98% and an average particle diameter of 0.47 μm and having good monodispersibility. The Mw of the resin particles was 8 × 10 ⁴ and the Tg was 40 ° C. Dispersion stabilizing resin (PS-4)

[0085]

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Example 1 <Preparation of lithographic printing plate precursor> A composition having the following contents was added to a paint shaker (Toyo Seiki Co., Ltd.) together with glass beads.
And dispersed for 60 minutes, and then the glass beads were separated by filtration to obtain a dispersion. Photocatalytic titanium oxide sol 40% solution: titanium oxide slurry 100 g STS-21 (manufactured by Ishihara Sangyo Co., Ltd.) Alumina sol 520 20% liquid (manufactured by Nissan Chemical Industries, Ltd.) 48 g polyvinyl alcohol: 10% aqueous solution of PVA-117 100 g (Kuraray 80% aqueous solution of melamine formaldehyde resin 1.1 g 10% aqueous solution of ammonium chloride 1.0 g

Support of ELP-1 type master (trade name, manufactured by Fuji Photo Film Co., Ltd.) used as electrophotographic lithographic printing plate precursor for light printing (Beck smoothness on one side of under side: 500 (sec / 10 cc)) The above composition was applied thereon using a wire bar, and dried at 130 ° C. for 30 minutes to form an image receiving layer having a coating amount of 5 g / m ² , thereby obtaining a lithographic printing original plate. Using a Beck smoothness tester (manufactured by Kumagai Riko Co., Ltd.), the lithographic printing plate precursor was measured for its smoothness (second / 10 cc) under the condition of an air volume of 10 cc, and it was 800 (second / 10 cc). . Further, 2 μl of distilled water was placed on the surface of the lithographic printing plate precursor, and the surface contact angle (degree) after 30 seconds was measured using a surface contact meter (CA-D, trade name, manufactured by Kyowa Interface Science Co., Ltd.). And 70 degrees.

Using the lithographic printing plate sample prepared as described above, a servoproter DA8400 manufactured by Graphtec Co., Ltd. capable of drawing a personal computer output was remodeled, and
The ink ejection head shown in FIG. 2 was mounted on the plotter section, and printing was performed on the lithographic printing original plate placed on the counter electrode spaced 1.5 mm apart using the oil-based ink (IK-1) described below. Performed plate making. At the time of plate making, the under layer provided immediately below the image receiving layer of the printing original plate sample and the counter electrode were electrically connected using a silver paste. The plate thus produced was adjusted to a plate surface temperature of 70 ° C. for 10 seconds, and an ink image was fixed with a Ricoh fuser (manufactured by Ricoh Co., Ltd.).

<Oil-based ink (IK-1)> Dodecyl methacrylate / acrylic acid copolymer (copolymerization ratio: 95/5)
(Weight ratio) of 10 g, 10 g of nigrosine and 30 g of Shellsol 71 were put together with glass beads in a paint shaker (manufactured by Tokyo Seiki Co., Ltd.) and dispersed for 4 hours to obtain a fine dispersion of nigrosine. 20 g (as solid content) of the resin particles (PL-1) of Production Example 1 of the ink resin particles, 7.5 g of the above nigrosine dispersion, and octadecene-half maleic acid octadecylamide copolymer 0.0
A black oil-based ink was prepared by diluting 8 g to 1 liter of Isopar G.

The drawing image of the plate-making product obtained was evaluated by observing it with an optical microscope at a magnification of 200 times. The image was clear with no bleeding or missing of fine lines and characters. Next, a 100 W high-pressure mercury lamp was applied to this plate making
Light irradiation was performed at a distance of 0 cm for 3 minutes. The surface wettability of the non-image portion and the image portion (solid image portion) of the obtained plate was measured by the contact angle with water. The surface of the non-image portion changed to 0 degrees, and the surface of the image portion was 90 degrees.

Next, the printing plate created as described above is
As a printing machine, Oliver 94 (manufactured by Sakurai Seisakusho)
And SLM-OD (Mitsubishi Paper Industries Co., Ltd.)
Was diluted 100 times with distilled water, and the solution was placed in a fountain solution receiving tray, and printed using a black ink for offset printing on a printing paper through a plate. When the printed image of the tenth printed material was visually evaluated using a 20-fold loupe, no background stain due to the adhesion of the printing ink to the non-image portion was observed, and the uniformity of the solid image portion was good. 200 more
Observation with an optical microscope at × 2 showed that fine lines and fine characters were not thinned or missing, and the image quality was good. More than 3,000 prints of the same print quality were obtained.

Examples 2 to 6 and Comparative Examples A and B [Preparation of Water-Resistant Support] A high-grade paper weighing 100 g / m ² was used as a substrate, and a back layer paint having the following composition was coated on one surface of the substrate with a wire. Apply using a bar, dry application amount 12g /
After the m ² back layer was provided, calendering was performed so that the back layer had a smoothness of about 50 (second / 10 cc).

(Coating for backcoat layer) ・ Kaolin (50% aqueous dispersion) 200 parts ・ Polyvinyl alcohol aqueous solution (10%) 60 parts ・ SBR latex (solid content 50%, Tg0 ° C.) 100 parts ・ Melamine resin (solid 80%, Sumiretz Resin SR-613) 5 parts

Next, under layer coatings A to G (detailed in Table 1) having the following composition were applied to the other surface of the substrate using a wire bar, and an under layer having a dry coating amount of 10 g / m ^{2 was} applied. After the provision, the under layer has a smoothness of 1500 (sec / 10
cc) Calendar processing was carried out to the extent. As shown in Table 1, each of the seven types of water-resistant supports thus obtained was subjected to support sample Nos.
01-No. 07.

[0095]

[Table 1]

<Coating for under layer> Carbon black (30% aqueous dispersion) Clay (50% aqueous dispersion) SBR latex (solid content 50%, Tg 25 ° C.) Melamine resin (solid content 80%, Sumi Let's Resin SR
-613)

Each of the above components was mixed with the composition shown in Table 1 above, and water was added so that the total solid content concentration was 25% to obtain coating solutions A to G for the under layers. 1) Specific electric resistance value of the under layer The specific electric resistance value of the under layer was measured as follows. Each of the underlayer coatings A to G was applied to a sufficiently degreased and washed stainless steel plate, and the applied amount was 10 g / m ² on a dry basis.
Was formed. With respect to the obtained seven types of samples, their intrinsic electric resistance values were measured by a three-terminal method provided with guard electrodes based on JIS K-6911. The results are shown in Table 2.

[0098]

[Table 2]

[Preparation of lithographic printing original plate] 01-No. 07, an image receiving layer was provided so that the applied amount of the dispersion of the following composition after drying was 5 g / m ² after drying to prepare lithographic printing original plates. The surface smoothness of each master was in the range of 700 to 800 (sec / 10 cc), and the contact angle with water was 50 degrees.

<Application of Image Receiving Layer> The following composition was placed in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) together with glass beads, dispersed for 10 minutes, and the glass beads were filtered off to obtain a dispersion. Was. Gelatin 10% aqueous solution 180 g Photocatalytic titanium powder: ST-01 (manufactured by Ishihara Sangyo Co., Ltd.) 45 g Colloidal silica 20% solution: Snowtec C 25 g (manufactured by Nissan Chemical Industries, Ltd.) Fluoroalkylester FC-430 ( 0.25 g Hardener 1.2 g CH ₂ = CHSO ₂ CH ₂ CONH (CH ₂ ) ₃ NHCOCH ₂ SO ₂ CH = CH ₂ water 100 g

The sample No. of the lithographic printing original plate prepared as described above was used. 2-No. In the same manner as in Example 1, plate making and fixing were performed using oil-based ink IK-1. At the time of plate making, the printing plate sample No. Two
No. The underlayer provided immediately below the image receiving layer of No. 8 and the counter electrode were electrically connected using a silver paste. Subsequently, in the same manner as in Example 1, irradiation with ultraviolet light was performed at a distance of 20 cm for 2.5 minutes. The contact angle between the non-image portion and the water of the image portion was 0 degree and 90 degrees, respectively.

Next, the printing plate prepared as described above was used as a dampening water by using a fully automatic printing machine (AM-2850, trade name, manufactured by Am Co., Ltd.), and SLM-OD was distilled water. The 50-fold diluted solution was placed in a fountain solution tray, and printing was performed through a plate-making product on a printing press using black ink for an offset printing press. The image quality of the drawn image of the plate-making product thus obtained was evaluated as follows. Table 3 shows the results
Shown in

[0103]

[Table 3]

1) Image quality of plate making The drawing image of the plate making obtained was processed by an optical microscope for 200 hours.
It was observed and evaluated at a magnification of 1 ×. In the table, ◎, ◎, and × are shown. ◎ There is no problem in the drawn image, and fine lines and fine characters are very good. ○ There is no problem in the drawn image, fine lines and fine characters are good. × The fine line and fine characters are missing or blurred and defective.

2) Printed Image When the image of the obtained printed matter was evaluated in the same manner as in the plate making image quality, the print image quality was exactly the same as the plate making image quality. 3) Printing durability The number of printed sheets was checked until the background contamination of the printed matter or the lack of the image could be visually discriminated.

Referring to the specific electric resistance values in Table 2, Table 3
Let us consider the result. In Examples 2 to 6 of the present invention, the underlayer had a specific electric resistance of as small as 10 ⁸ to 10 ³ Ω · cm. High printing durability. On the other hand, the originals of Comparative Examples A and B having specific electric resistance values as large as 10 ¹² to 10 ¹¹ Ω · cm
The image is missing or blurred. In addition, since the resin layer of the drawn image becomes thin as a result of bleeding, printing durability is low. That is, the higher the conductivity of the support underlayer immediately below the image receiving layer, the higher the plate making quality and printing quality.

Example 7 <Preparation of a lithographic printing original plate> A composition having the following contents was added together with glass beads to a paint shaker (Toyo Seiki Co., Ltd.)
And dispersed for 5 minutes, and the glass beads were separated by filtration to obtain a dispersion. Photocatalytic titanium oxide sol 30% solution: STS-OZ 150 g (Ishihara Sangyo Co., Ltd.) Colloidal silica: Snowtec C 25 g Self-crosslinking acrylate latex 40% solution 20 g Nipol LX855 (Daicel Chemical Industries, Ltd.) Water 93 g

Using the water-resistant support used in Example 6, the above composition was applied thereon using a wire bar.
After drying at 0 ° C. for 60 minutes, an image receiving layer having a coating amount of 4 g / m ² was formed, and a lithographic printing original plate was obtained. The Beck smoothness of the surface layer was 850 (sec / 10 cc), and the contact angle with water was 75 degrees. This printing plate and an oil-based ink (IK-
2) In the same manner as in Example 1,
The printing plate was subjected to ultraviolet irradiation treatment, and offset printing was performed.

<Preparation of Oil-Based Ink (IK-2)> Dodecyl methacrylate / methacrylic acid copolymer (copolymerization ratio:
A 95/5 weight ratio of 10 g, 10 g of alkali blue and 30 g of Isopar H were put together with glass beads into a paint shaker (manufactured by Toyo Seiki Co., Ltd.) and dispersed for 4 hours.
A fine dispersion of alkali blue was obtained. 45 g (as solid content) of the resin particles (PL-2) of Production Example 2 of resin particles, 18 g of the above-described alkali blue dispersion, and 0.16 g of octyl vinyl ether-octadecylamide hemi-maleic acid copolymer were mixed with 1 liter of Isopar G. To obtain a blue oil-based ink.

[0110] The obtained printed matter has a clear image quality with no stain on the non-image area, similarly to the printing plate of Example 1.
The printing durability was as good as 3,000 sheets or more.

Example 8 <Preparation of a lithographic printing original plate> A composition having the following contents was placed in a homogenizer dispersing machine (manufactured by Nippon Seiki Co., Ltd.) and the number of rotations was 1
The mixture was dispersed at 10,000 rpm for 30 minutes to obtain a dispersion. Photocatalytic titanium oxide powder: ST-21 50 g Acrylic resin: Dianal LR-689 40% solution 40 g (manufactured by Mitsubishi Rayon Co., Ltd.) Acrylic resin particle dispersion having the following content 5 g (as solid content) methyl isobutyl ketone 210 g

(Acrylic resin particles) 8 g of acrylic acid,
AA-6 (trade name: methyl methacrylate macromonomer manufactured by Toa Gosei Chemical Co., Ltd.) 3 g, ethylene glycol dimethacrylate 2 g, methyl 3-mercaptopropionate 0.3 g, and methyl ethyl ketone 55 g were heated at a temperature under a nitrogen stream. Heated to 60 ° C. To this,
0.2 g of 2'-azobis (isovaleronitrile) was added and reacted for 3 hours.
Reacted for hours. The resulting dispersion had a conversion of 98%, the average particle size of the dispersed resin particles was 0.13 μm, and had good monodispersity (particle size measurement: CAPA-500 (trade name, manufactured by Horiba, Ltd.)) ).

This dispersion was treated with Sample No. 3 of Example 3.
A lithographic printing original plate was obtained by coating the same water-resistant support as used in Example 4 with a wire bar so as to have a coating amount of 5 g / m ² and drying. The surface Beck smoothness of the obtained image receiving layer is 6
50 (sec / 10 cc) and the contact angle with water on the surface was 85 degrees. This printing original plate was subjected to plate making and fixing in the same manner as in Example 1 except that the following oil-based ink (IK-3) was used instead of the oil-based ink (IK-1).

<Oil-Based Ink IK-3> A mixture of 300 g of the white dispersion (PL-4) obtained in Production Example 4 of latex particles and 5 g of Victoria Blue B was heated at a temperature of 100 ° C.
And heated and stirred for 4 hours. After cooling to room temperature, 200
The residual dye was removed through a mesh nylon cloth to obtain a black resin dispersion having an average particle size of 0.47 μm. 260 g of the above black resin dispersion, 0.07 g of zirconium naphthenate, FOC-1600 (Nissan Chemical Co., Ltd.)
20 g of Hexadecyl alcohol)
A blue oil-based ink was prepared by diluting 1 to 1 liter. Next, using a 150 W xenon lamp on the entire surface of the plate making master, the light source was irradiated with light from a distance of 10 cm for 5 minutes.

The contact angle with water on the surface of the non-image portion was 0 °, and that on the surface of the image portion was 95 °. This printing plate was subjected to offset printing in the same manner as in Example 1. The obtained printed material had a clear image quality with no stain on the non-image area, as in the printing plate of Example 1, and had a good printing durability of 3,000 sheets or more.

Example 9 <Preparation of a lithographic printing original plate> A composition having the following contents was added together with glass beads to a paint shaker (Toyo Seiki Co., Ltd.)
And dispersed for 20 minutes, and the glass beads were separated by filtration to obtain a dispersion. Photocatalytic titanium oxide ST-01 45 g Polypropylene oxide-modified starch 18 g PENON HV-2 (manufactured by Nisseki Chemical Co., Ltd.) Alumina Sol 520 24 g 40% Glyoxal 40% solution 5 g Water 258 g

This dispersion was degreased to a thickness of 150.
Using a wire bar on a μm aluminum plate, apply 11
Heat at 0 ° C. for 20 minutes. An image receiving layer having a coating amount of 3 g / m ² was formed to prepare a lithographic printing plate. The surface of the obtained image receiving layer had a Beck smoothness of 900 (sec / 10 cc) and a contact angle with water of 45 degrees. Using this original plate for printing and the oil-based ink (IK-4) having the following content, plate-making and light irradiation were performed in the same manner as in Example 1 to perform offset printing as a printing plate.

<Oil-Based Ink (IK-4)> A mixture of 500 g of the white dispersion (PL-3) obtained in Production Example 3 of resin particles and 7.5 g of Sumicaron Black was heated to 100 ° C.
And stirred under heating for 6 hours. After cooling to room temperature, a 200-mesh nylon cloth was passed through to remove the remaining dye, whereby a black resin dispersion having an average particle diameter of 0.40 μm was obtained. Each of the obtained prints was, like the printing plate of Example 1,
All of the plates had clear images with no stain on the non-image area, and had good printing durability of 10,000 sheets or more.

Example 10 A lithographic printing original plate was prepared in the same manner as in Example 8 except that a corona-treated PET film having a thickness of 100 μm was used as the water-resistant support. Printing was performed in the same manner. The obtained printed material had a clear image quality with no stain on the non-image area, as in the printing plate of Example 8, and had a good printing durability of 10,000 sheets or more.

[0120]

According to the lithographic printing plate precursor of the present invention, the anatase type titanium oxide particles and the binder have a contact angle of 20 ° or more with water on the surface and 10 ° or less after irradiation with ultraviolet light. By having an image receiving layer containing a resin, a lithographic printing plate capable of printing a large number of clear, clear image quality prints without soiling can be obtained by dry desensitization treatment by irradiation with ultraviolet light. Further, the method of preparing a lithographic printing plate of the present invention makes it possible to perform simple image formation and dry desensitization treatment by irradiating ultraviolet light by using an ink jet recording method or the like on the lithographic printing plate precursor, and to improve printing durability. A lithographic printing plate capable of printing a large number of clear printed images with excellent image quality, no background smear, and no image loss, distortion, or bleeding can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus system used in the present invention.

FIG. 2 is a schematic configuration diagram illustrating a main part of an inkjet recording apparatus used in the present invention.

FIG. 3 is a partial sectional view of a head of an ink jet recording apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet recording apparatus 2 Master 3 Computer 4 Bus 10 Head 10a Discharge slit 10c Counter electrode 11 Oil-based ink 101 Upper unit 102 Lower unit

Claims (8)

[Claims] Claims: 1. A water-resistant support, comprising a layer containing at least anatase-type titanium oxide particles and a binder resin,
A lithographic printing plate precursor, wherein the surface of the layer has a contact angle with water of 20 degrees or more, and the contact angle with water of the surface after irradiation of the ultraviolet light irradiated portion is 10 degrees or less. 2. The smoothness of the layer surface is 3 in Beck's smoothness.
2. The speed is not less than 0 (second / 10 cc).
The lithographic printing original plate described. 3. The lithographic printing plate precursor according to claim 1, wherein the water-resistant support has a specific electrical resistance value of at least a portion immediately below the layer of 10 ¹⁰ Ω · cm or less. 4. A colored image is formed on an image-receiving layer of a lithographic printing plate precursor having an image-receiving layer containing at least anatase-type titanium oxide particles and a binder resin on a water-resistant support using an inkjet recording method. Irradiating the entire surface of the image receiving layer with ultraviolet light to convert a non-image portion into a hydrophilic surface state that does not accept the printing ink to form a lithographic printing plate. . 5. The lithographic printing plate according to claim 4, wherein the image formation using the ink jet recording system is performed by ejecting oil-based ink from a nozzle in a droplet form. Method. 6. A solid and hydrophobic resin particle is dispersed at least at room temperature in a non-aqueous solvent of an oil-based ink having an electric resistance of not less than 10 ⁹ Ω · cm and a dielectric constant of not more than 3.5. 6. The method for preparing a lithographic printing plate according to claim 5, wherein the particles are colored or further colored particles are dispersed. 7. The particles dispersed in the oil-based ink,
7. The method according to claim 5, wherein the particles are positively or negatively charged particles and the oil-based ink is ejected from a nozzle using an electrostatic field. 8. The lithographic plate according to claim 5, wherein the water-resistant support has an intrinsic electric resistance value of at least a portion immediately below the image receiving layer of 10 ¹⁰ Ω · cm or less. How to make a printing plate.