WO2011078175A1

WO2011078175A1 - Planographic printing original plate, and method for producing planographic printing plate

Info

Publication number: WO2011078175A1
Application number: PCT/JP2010/073018
Authority: WO
Inventors: 孝教武井; 由人大橋; 正雄内海; 幸雄徳永; 秀人木山; 勝長濱; 雄一朗小西
Original assignee: 三菱製紙株式会社
Priority date: 2009-12-25
Filing date: 2010-12-21
Publication date: 2011-06-30

Abstract

Provided is a planographic printing original plate which can be produced by means of direct plate making using the inkjet method, has excellent image quality, and can exert superior printing durability and stain resistance. Also provided is a method for producing a planographic printing plate. Provided is a planographic printing original plate which is characterized by having image-receiving layer (A) which is disposed on a water-resistant support body, and which mainly contains inorganic microparticles, and image-receiving layer (B) which is disposed on the side which is farther away from the water-resistant support body than image-receiving layer (A), and which mainly contains a cationic colloidal silica, or contains mainly a colloidal silica along with a cationic compound.

Description

Planographic printing plate precursor and lithographic printing plate making method

The present invention relates to a lithographic printing plate precursor for making a plate directly from digital information and a plate making method thereof.

The lithographic printing plate precursors currently used in the printing field include (1) a direct drawing type in which an image receiving layer is provided on a water-resistant support, and (2) a photoconductive layer on the water-resistant support. An electrophotographic type provided, (3) a silver salt photographic type provided with a silver halide emulsion layer on a water-resistant support, and (4) a PS plate provided with a photosensitive resin on a support such as metal. Etc. Among them, the lithographic printing plate precursor (1) described above can be directly made by forming an oleophilic image on the image-receiving layer, so that the other lithographic printing methods (2), (3) and (4) above are used. Compared to the original plate, the plate can be easily produced. The lithographic printing plate produced in this way is surface-treated with a desensitizing liquid (etching liquid) to desensitize non-image areas and then used for printing.

For example, a laser beam printer may be used as a method for converting electronically edited information into a digital electric signal and writing image information directly on the image receiving layer. When this method is used, electronically edited information can be easily enlarged / reduced, negative / positive converted, shaded, etc., so that many functions can be provided. Laser beam printers need to increase the resolution in order to improve the quality of printed images required in recent years. However, since such laser beam printers generally have finer toner particles, the toner scatters around the development area. The toner that is easily scattered in the non-image area causes printing stains called toner fog.

On the other hand, when image information is directly printed on the image receiving layer by the ink jet method, the above-described toner fog is remarkably improved. However, the ink used for the ink jet system is mainly one using water as a solvent, and additionally contains dyes or pigments, alcohols, various additives and the like. For this reason, the printed part (image part) contains only a very small amount of oleophilic components, so the difference between the oleophilic property of the image part and the hydrophilicity of the non-image part is not sufficient, and sufficient printing durability and stain resistance. The present situation is that a lithographic printing plate having properties cannot be obtained.

As a lithographic printing plate precursor that directly prints image information on an image receiving layer by an inkjet method and then uses for printing, a lithographic printing plate precursor provided with a polymer type image receiving layer on a water-resistant support is known. . For example, JP-A-5-204138 (Patent Document 1) discloses a lithographic printing plate precursor provided with an image receiving layer containing a linear organic polymer, and JP-A 2000-108537 (Patent Document 2). Discloses a lithographic printing plate precursor provided with an image receiving layer containing a polymer having a component having an acid group and a component having an onium group. Japanese Patent Laid-Open No. 2000-233581 (Patent Document 3) discloses a diene structure. A lithographic printing plate precursor provided with an image-receiving layer containing a polymer pendant with a group having s is disclosed. JP-A 2006-264093 (Patent Document 4) discloses a lithographic printing plate precursor provided with an image receiving layer containing a hydrophilic polymer crosslinked with a crosslinking agent having a carbodiimide group and a surfactant.

On the other hand, a lithographic printing plate precursor having a porous image-receiving layer by mainly containing inorganic fine particles, etc., in contrast to the above-described polymer-type lithographic printing plate precursor, is also known. As the layer, for example, in Japanese Patent Laid-Open No. 8-324145 (Patent Document 5), an image receiving layer composed of non-greasy metal powder such as zinc oxide and alumina is disclosed in Japanese Patent Laid-Open No. 9-29926 (Patent Document 5). Document 6) describes an image receiving layer having a porous or particulate form for taking up ink-jet ink, and Japanese Patent Application Laid-Open No. 9-58144 (Patent Document 7) discloses a polymer binder, clay, silica, JP-A-9-99662 (Patent Document 8) discloses an image receiving layer containing a pigment that becomes hydrophilic with an etching solution such as alumina, and a pigment for forming irregularities on the surface. An image receiving layer having a three-dimensional network structure formed from inorganic fine particles having a uniform primary particle size of 100 nm or less and a water-soluble resin is disclosed in JP-A-2000-44884 (Patent Document 9) coated with an inorganic gel dispersion. An image receiving layer having an inorganic xerogel obtained in this manner is disclosed.

The use of colloidal silica in the void-type image receiving layer is also known conventionally. For example, in addition to the above-mentioned Patent Document 8, JP-A-10-296945 (Patent Document 10) and JP-A-10-315645 are disclosed. (Patent Document 11) discloses an image receiving layer containing inorganic fine particles having an average particle diameter of 1 to 6 μm and colloidal silica having an average primary particle diameter of 10 to 50 nm.

Furthermore, it is also known to provide a plurality of porous layers on the side having a plurality of image receiving layers. For example, JP 2003-231374 A (Patent Document 12), JP 2004-42531 A (Patent Document 13). Discloses a lithographic printing plate precursor provided with an undercoat layer mainly containing colloidal silica and a hydrophilic layer. JP-A-2008-183846 (Patent Document 14) discloses a solvent absorption containing an inorganic pigment and a resin. A lithographic printing plate precursor in which a layer and an image receiving layer containing colloidal silica are laminated is disclosed, and JP 2007-190804 A (Patent Document 15) discloses an inorganic pigment / binder of an image receiving layer close to a support. A lithographic printing plate precursor in which the ratio is smaller than the ratio of the image receiving layer farther from the support is disclosed.

Japanese Patent Laid-Open No. 5-204138 JP 2000-108537 A JP 2000-233581 A JP 2006-264093 A JP-A-8-324145 Japanese Patent Laid-Open No. 9-29926 JP-A-9-58144 Japanese Patent Laid-Open No. 9-99662 JP 2000-44884 A JP-A-10-296945 JP-A-10-315645 JP 2003-231374 A JP 2004-42531 A JP 2008-183846 A JP 2007-190804 A

However, polymer type lithographic printing plate precursors as described in Patent Documents 1 to 4 do not provide satisfactory image quality, and printing durability and stain resistance are not sufficiently satisfactory. In addition, a planographic printing plate precursor having a porous image-receiving layer mainly containing inorganic fine particles as described in Patent Documents 5 to 9 is likely to be stained when printed. Moreover, it is difficult for a lithographic printing plate precursor using colloidal silica for the void-type image receiving layer as described in Patent Documents 10 and 11 to achieve both sufficient printing durability and stain resistance. In addition, a lithographic printing plate precursor having a plurality of porous layers on the side having a plurality of image receiving layers as described in Patent Documents 12 to 15 has both sufficient printing durability and stain resistance. It is difficult.

An object of the present invention is to provide a lithographic printing plate precursor capable of direct plate making by an ink jet method, having excellent image quality, and capable of achieving both good printing durability and stain resistance, and a lithographic printing plate It is to provide a plate making method.

The above-mentioned subject is achieved by the following invention.
(1) An image receiving layer A mainly containing inorganic fine particles on a water-resistant support, and whether cationic colloidal silica is mainly contained on the side farther from the water-resistant support than the image receiving layer A Or a lithographic printing plate precursor comprising an image-receiving layer B mainly containing colloidal silica and containing a cationic compound.
(2) The image receiving layer B is a layer mainly containing a cationic colloidal silica having an average primary particle diameter of 30 nm or more, or a layer mainly containing a non-spherical cationic colloidal silica. The lithographic printing plate precursor described in 1.
(3) The non-spherical cationic colloidal silica has an average primary particle size of 25 to 60 nm and a ratio of the average secondary particle size to the average primary particle size of 1.4 to 3.1. The lithographic printing plate precursor as described in 2).
(4) The lithographic printing plate precursor as described in (2) above, wherein the image receiving layer B is a layer mainly containing cationic colloidal silica having an average primary particle diameter of 30 nm or more.
(5) The lithographic printing plate precursor as described in (4) above, wherein the image receiving layer B is a layer mainly containing cationic colloidal silica having an average primary particle diameter of 50 nm or more.
(6) The lithographic printing plate precursor as described in (1) above, wherein the image receiving layer B contains polyvinyl alcohol and a cellulose derivative.
(7) The lithographic printing plate precursor as described in any one of (1) to (6) above, wherein the inorganic fine particles contained in the image receiving layer A are inorganic fine particles having a specific surface area of more than 150 m ² / g by BET method. .
(8) The lithographic printing plate precursor as described in (7) above, wherein the inorganic fine particles contained in the image receiving layer A are gas phase method silica having a specific surface area by the BET method exceeding 300 m ² / g.
(9) A method for making a lithographic printing plate, comprising printing an aqueous pigment ink on the lithographic printing plate precursor according to any one of (1) to (8) above by an inkjet method.
(10) The method for making a lithographic printing plate as described in (9) above, wherein the aqueous pigment ink is an aqueous pigment ink containing a pigment and a styrene-acrylic copolymer resin or a styrene-methacrylic copolymer resin.
(11) The method for making a lithographic printing plate as described in (9) or (10) above, comprising desensitization treatment after printing the aqueous pigment ink on the lithographic printing plate precursor and before starting printing.

According to the present invention, a lithographic printing plate precursor capable of direct plate making by an ink jet method, having excellent image quality, and having both good printing durability and stain resistance, and a lithographic printing plate making method Can be provided.

The present invention will be described in detail below.

[Embodiment 1: Planographic printing plate precursor]
The lithographic printing plate precursor according to this embodiment comprises an image-receiving layer A mainly containing inorganic fine particles on a water-resistant support, and a cationic property on the side farther from the water-resistant support than the image-receiving layer A. A lithographic printing plate precursor comprising an image receiving layer B mainly containing colloidal silica or containing colloidal silica as a main component and containing a cationic compound. According to such a lithographic printing plate precursor, direct plate making by an ink jet method is possible, it has excellent image quality, and it is possible to achieve both good printing durability and stain resistance.

(Image forming layer B)
The image receiving layer B provided on the side farther from the support than the image receiving layer A of the present invention mainly contains cationic colloidal silica, or mainly contains colloidal silica and contains a cationic compound. It is an image receiving layer. Here, “mainly contained” means that the mass ratio of the cationic colloidal silica to the total solid mass of the image receiving layer B or the mass ratio of the colloidal silica is 50% by mass or more, Preferably it is 70 mass% or more, More preferably, it is 85 mass% or more. In the present invention, the image-receiving layer B mainly contains cationic colloidal silica having an average primary particle diameter of 30 nm or more, or is a layer mainly containing non-spherical cationic colloidal silica. It is preferable from the viewpoint of obtaining a lithographic printing plate precursor having good printing durability and stain resistance.

When the image receiving layer B is a layer mainly containing non-spherical cationic colloidal silica, the non-spherical cationic colloidal silica has an average primary particle diameter of 25 to 60 nm and an average with respect to the average primary particle diameter. The secondary particle size ratio is preferably 1.4 to 3.1. As a result, a lithographic printing plate precursor having more excellent printing durability and stain resistance can be obtained.

As used herein, “ratio of average secondary particle size to average primary particle size is 1.4 to 3.1” in non-spherical cationic colloidal silica means that secondary particles are It means a state in which 2 to 3 primary particles of colloidal silica are connected, and a state in which 5 or more primary particles are connected is not included. As long as the requirement that the average primary particle diameter of colloidal silica is 25 to 60 nm and the ratio of the average secondary particle diameter to the average primary particle diameter is 1.4 to 3.1 is different, 2 More than one type of colloidal silica can also be used. The average primary particle size of colloidal silica is the average particle size of 100 particles existing within a certain area from an electron micrograph of particles dispersed until the primary particle size can be determined. The ratio of the average secondary particle diameter to the average primary particle diameter of the colloidal silica is determined as the number median diameter using a laser scattering type particle size distribution meter (for example, LA910, manufactured by Horiba, Ltd.), It is the value which computed the ratio with respect to the average primary particle diameter calculated | required above.

As a method for obtaining such colloidal silica, a method of modifying the surface of colloidal silica with a cationic polymer or a water-soluble polyvalent metal compound, which will be described later, or a method of modifying the surface of colloidal silica with the following cationic silane coupling agent or the like. And a method of introducing a cationic group to the particle surface during the production process of colloidal silica. Examples of the colloidal silica used for modifying the surface of the colloidal silica include a trade name Quarton PL series manufactured by Fuso Chemical Industry Co., Ltd., and Cataloid SI-50 manufactured by JGC Catalysts & Chemicals Co., Ltd. Among these, a method of modifying the surface of colloidal silica using a water-soluble polyvalent metal compound is more preferable.

It is preferable to use an amino group-containing silane coupling agent as the cationic silane coupling agent. Examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl). ) -Γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like.

The solid content mixing ratio of the cationic polymer or water-soluble polyvalent metal compound for modifying the cationic colloidal silica (parts by weight of colloidal silica / mass by weight of the cationic polymer or water-soluble polyvalent metal compound) is 100/2 to 100/20. Is preferable, and 100/5 to 100/15 is more preferable. When the colloidal silica is treated with the cationic silane coupling agent, the solid content mixing ratio of the cationic silane coupling agent (parts by weight of colloidal silica / parts by weight of the cationic silane coupling agent) is 100 / 0.01 to 100. / 20 is preferable, and 100 / 0.05 to 100/10 is more preferable.

In the present invention, it is most preferable that the image receiving layer B mainly contains cationic colloidal silica having an average primary particle size of 30 nm or more from the viewpoint of obtaining good printing durability and stain resistance. When the layer B mainly contains cationic colloidal silica having an average primary particle diameter of 50 nm or more, the stain resistance is further improved. As used herein, "cationic colloidal silica having an average primary particle diameter of 30 nm or more" refers to cationic colloidal silica having colloidal particles of spherical primary particles having an average primary particle diameter of 30 nm or more. Say. The average primary particle diameter of the cationic colloidal silica is desirably 300 nm or less from the viewpoint of obtaining good printing durability.

The cationic colloidal silica used in the present invention is, for example, a product name of Silica LGT from Lion Corporation, a product name of Fine Cataroid from JGC Catalysts Chemical Co., Ltd., or ST- from Nissan Chemical Industries, Ltd. These are commercially available under trade names such as AK-L, ST-UP-AK, ST-PS-M-AK, ST-AK-YL, and these can be obtained and used.

In this embodiment, when the image receiving layer B is a layer mainly containing colloidal silica and containing a cationic compound, the colloidal silica used together with the cationic compound contained in the image receiving layer B is described in detail. It is an anionic colloidal silica, and a preferable average primary particle diameter is the same as that of the cationic colloidal silica described above. Examples of such anionic colloidal silica include Snowtex ST-20, ST-30, ST-C, ST-OL40, ST-OZL and the like commercially available from Nissan Chemical Industries, Ltd., and Fuso Chemical Industries, Ltd. Commercially available PL-3L, PL-5, PL-7, etc. can be obtained and used.

In this embodiment, when the image receiving layer B is a layer mainly containing colloidal silica and containing a cationic compound, the cationic compound used together with the colloidal silica contained in the image receiving layer B is a cationic polymer. Or a water-soluble polyvalent metal compound is mentioned. These cationic polymers or water-soluble polyvalent metal compounds can also be used to modify the surface of colloidal silica when producing non-spherical cationic colloidal silica.

Examples of the cationic polymer include polyethyleneimine; polydiallylamine; polyallylamine; alkylamine polymer; JP 59-20696, JP 59-33176, JP 59-33177, JP JP 59-1555088, JP 60-11389, JP 60-49990, JP 60-83882, JP 60-109894, JP 62-198493 JP, JP 63-49478, JP 63-115780, JP 63-280681, JP 1-40371, JP 6-234268, JP 7-125411. No. 1 and tertiary amino groups and quaternary ammonium bases described in JP-A-10-193976 Over is preferably used. The molecular weight of these cationic polymers is preferably about 1,000 to 100,000.

The water-soluble polyvalent metal compound includes, as a water-soluble polyvalent metal salt, a metal selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum. A water-soluble salt is mentioned. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride , Ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexa Hydrate, nickel amidosulfate tetrahydrate, nickel phenolsulfonate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, basic polyaluminum hydroxide, aluminum sulfate nonahydrate, aluminum chloride hexahydrate , Ferrous bromide, ferrous chloride, ferric chloride, sulfuric acid Iron, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zinc phenolsulfonate, zirconium acetate, zirconium chloride, zirconium chloride octahydrate, zirconium hydroxychloride, chromium acetate, Examples include magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n-hydrate, and the like. Some of them have an inappropriately low pH, and in that case, the pH can be appropriately adjusted and used. As used herein, the term “water-soluble” refers to dissolving 1% by mass or more in water at normal temperature and pressure. In the present embodiment, a water-soluble metal salt made of zirconium or aluminum is preferable. As a water-soluble metal salt composed of zirconium, for example, ZA-30 is commercially available from Daiichi Rare Element Chemical Co., Ltd. As a water-soluble metal made of aluminum, for example, water treatment agent under the name of polyaluminum chloride (PAC) from Taki Chemical Co., Ltd., under the name of polyaluminum hydroxide (Paho) from Asada Chemical Co., Ltd. It is sold under the name Purachem WT by Riken Green, Inc., and it is also sold by other manufacturers for the same purpose, and various grades are readily available.

The image receiving layer B can contain a binder. The binder content in the image receiving layer B is preferably 10% by mass or less, more preferably 6% by mass or less of the solid content coating amount of the image receiving layer B. Thereby, both excellent printing durability and stain resistance can be achieved. Examples of the binder to be used include those similar to the hydrophilic binder contained in the image receiving layer A to be described later. Among them, polyvinyl alcohol and cellulose derivatives, in particular, polyvinyl alcohol and hydroxyethyl cellulose are used in combination. It is possible to improve the stain resistance without deteriorating the property. The ratio (mass ratio) when polyvinyl alcohol and cellulose derivative are used in combination is preferably in the range of 7: 3 to 3: 7.

The solid content coating amount of the image receiving layer B is preferably 0.01 to 8.0 g / m ² , more preferably 0.05 to 2.0 g / m ² , and still more preferably 0.05 to 1.5 g / m ² . Thereby, particularly good image quality can be obtained.

(Image forming layer A)
Next, the image receiving layer A will be described. The image receiving layer A of the present invention mainly contains inorganic fine particles. Here, “mainly containing inorganic fine particles” means that the inorganic fine particles are contained in an amount of 50% by mass or more, more preferably 60% by mass or more, based on the solid content coating amount of the image receiving layer A. That is. The content of the inorganic fine particles in the image receiving layer A of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, particularly 65 to 90% by mass with respect to the total solid content of the image receiving layer A. The range of is preferable. Thus, the image receiving layer having a high content of inorganic fine particles becomes a porous image receiving layer having a high porosity.

Examples of the inorganic fine particles contained in the image receiving layer A include various known fine particles such as amorphous synthetic silica, alumina, alumina hydrate, calcium carbonate, magnesium carbonate, titanium dioxide, and good productivity can be obtained. In this respect, amorphous synthetic silica, alumina, or alumina hydrate is preferable. Furthermore, from the viewpoint of obtaining good ink absorptivity, amorphous synthetic silica, particularly gas phase method silica described later, is particularly preferably used. The average secondary particle size of the inorganic fine particles contained in the image receiving layer A of the present invention is preferably less than 1.0 μm.

Amorphous synthetic silica can be roughly classified into wet method silica, gas phase method silica, and others depending on the production method. The wet process silica is further classified into precipitation process silica, gel process silica, and sol process silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification. Precipitated silica is commercially available, for example, from Tosoh Silica Co., Ltd. under the trade name of nipseal and from Tokuyama Co., Ltd. under the trade name of Tokuseal. Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During aging, the microparticles dissolve and reprecipitate so as to bind the other primary particles, so that the distinct primary particles disappear and form relatively hard aggregated particles having an internal void structure. As the gel method silica, for example, it is commercially available from Tosoh Silica Co., Ltd. under the trade name of Nipgel, and from Grace Japan Co., Ltd. under the trade names of Cyloid and Silojet. The sol method silica is also called colloidal silica, and is obtained by heating and aging a silica sol obtained through metathesis of sodium silicate acid or the like through an ion exchange resin layer. Sol silica is commercially available from Nissan Chemical Industries, Ltd. under the name Snowtex.

Vapor phase silica is also called dry silica compared to wet silica, and is generally made by flame hydrolysis. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or in silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase method silica is commercially available from Nippon Aerosil Co., Ltd. under the trade name Aerosil and from Tokuyama Co., Ltd. under the QS type trade name.

The inorganic fine particles in the present invention are preferably inorganic fine particles having a specific surface area of more than 150 m ² / g as measured by the BET method because the stain resistance is improved.

Further, among inorganic fine particles, vapor phase method silica having a specific surface area by BET method exceeding 300 m ² / g can be preferably used. Thereby, dirt resistance improves. The BET method referred to in the present invention is a method for measuring the surface area of a powder by a vapor phase adsorption method, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from an adsorption isotherm. Usually, as the adsorbed gas, a large amount of nitrogen gas is used, and the method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller formula, called the BET formula, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET formula, and the specific surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

The gas phase method silica in the present invention is preferably dispersed in the presence of a cationic compound. The average secondary particle diameter of the dispersed vapor phase process silica is preferably less than 1.0 μm. As a dispersion method, gas phase method silica and a dispersion medium are premixed by ordinary propeller stirring, turbine type stirring, homomixer type stirring, etc., and then a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, an ultrahigh pressure It is preferable to perform dispersion using a pressure disperser such as a homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like. The average secondary particle diameter of the inorganic fine particles referred to in the present invention can be measured as a number median diameter using a laser scattering type particle size distribution meter (for example, LA910 manufactured by Horiba, Ltd.).

In the present invention, wet process silica pulverized to an average secondary particle size of less than 1.0 μm can also be preferably used. As the wet method silica used here, precipitation method silica or gel method silica is preferable, and precipitation method silica is particularly preferable.

Since wet-process silica produced by a normal method has an average aggregate particle diameter of 1.0 μm or more, it is used after being finely pulverized. As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. At this time, increase in the initial viscosity of the dispersion is suppressed, high concentration dispersion is possible, and pulverization / dispersion efficiency is increased so that it can be further pulverized into fine particles. It is preferable to do. By using a high concentration dispersion, the productivity of the lithographic printing plate precursor is also improved. As the wet process silica in the present invention, wet process silica particles having an average aggregated particle diameter of 5 to 50 μm are preferable, and wet process silica fine particles obtained by pulverizing them in the presence of a cationic compound can be used.

A specific method for obtaining wet method silica fine particles having an average secondary particle diameter of less than 1.0 μm in the present invention will be described. First, silica particles and a cationic compound are mixed in a dispersion medium mainly composed of water, and at least one dispersion device such as a sawtooth blade type dispersion machine, a propeller blade type dispersion machine, or a rotor stator type dispersion machine is used. Used to obtain a preliminary dispersion. If necessary, an appropriate low boiling point solvent or the like may be added to the aqueous dispersion medium. The silica pre-dispersion preferably has a higher solid content, but if the concentration is too high, the dispersion becomes impossible. Therefore, the preferred range is 15 to 40% by mass, and more preferably 20 to 35% by mass. Next, the silica particles are pulverized by applying the silica pre-dispersion to mechanical means having a stronger shearing force to obtain a wet process silica fine particle dispersion having an average secondary particle size of less than 1.0 μm. As a mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

As the cationic compound used for dispersion or pulverization of the vapor phase silica and the wet method silica, a cationic polymer can be preferably used. The cationic compound and the cationic polymer are synonymous with the cationic compound and the cationic polymer used together with the colloidal silica in the image receiving layer B. In particular, a diallylamine derivative is preferably used as the cationic polymer. In terms of dispersibility and dispersion viscosity, the molecular weight of these cationic polymers is preferably about 2000 to 100,000, and more preferably about 2000 to 30,000.

Further, alumina or alumina hydrate is also preferably used as the inorganic fine particles used for the image receiving layer A. Alumina or alumina hydrate is aluminum oxide or its hydrate, which may be crystalline or amorphous, and has an amorphous shape, a spherical shape, a plate shape, or the like. Any of these may be used or used in combination.

As the alumina oxide that can be used in the present invention, γ-alumina, which is a γ-type crystal of aluminum oxide, is preferable, and δ group crystal is particularly preferable. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particles of several thousand to several tens of thousands nm are averaged by ultrasonic, high-pressure homogenizer, counter collision type jet crusher, etc. Those having a secondary particle size of less than 1.0 μm can be used.

The alumina hydrate that can be used in the present invention is represented by a constitutional formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The hydrated aluminum oxide can be obtained by a known production method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, hydrolysis of aluminate, and the like. The average secondary particle size of the alumina hydrate used in the present invention is preferably less than 1.0 μm.

Alumina and alumina hydrate used in the present invention are preferably those in which the average secondary particle size is dispersed to less than 1.0 μm by a known dispersant such as acetic acid, lactic acid, formic acid, methanesulfonic acid, hydrochloric acid, nitric acid and the like. Used.

Two or more kinds of inorganic fine particles can be used in combination from the above-mentioned inorganic fine particles. For example, combined use of finely pulverized wet method silica and vapor phase method silica, combined use of finely divided wet method silica and alumina or alumina hydrate, and combined use of vapor phase method silica and alumina or alumina hydrate. It is done. The ratio (mass ratio) in the case of this combined use is preferably in the range of 7: 3 to 3: 7 in any aspect.

In the present invention, it is preferable to use a binder together with the inorganic fine particles constituting the image receiving layer A. As such a binder, a hydrophilic binder having high transparency and higher ink permeability is preferably used. For example, polyvinyl alcohol (including modified products thereof), gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, carrageenan, agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, hydroxypropyl cellulose And various cellulose derivatives such as carboxymethylcellulose. Two or more of these hydrophilic binders can be used in combination. When using a hydrophilic binder, it is important that the hydrophilic binder does not swell during the initial penetration of the ink and block the voids. From this point of view, a hydrophilic binder having a relatively low swellability around room temperature is preferable. Used. A preferred hydrophilic binder is polyvinyl alcohol, and particularly, completely or partially saponified polyvinyl alcohol or cationically modified polyvinyl alcohol is preferred.

Particularly preferred among polyvinyl alcohols are those having a saponification degree of 80% or more or those having been completely saponified. Those having an average degree of polymerization of 200 to 5000 are preferred.

Examples of the cation-modified polyvinyl alcohol include polyvinyl alcohol having primary to tertiary amino groups or quaternary ammonium groups in the main chain or side chain of polyvinyl alcohol as described in JP-A-61-10383. It is alcohol.

In the present invention, if necessary, a hardening agent can be used together with the hydrophilic binder constituting the image receiving layer A. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethyl) urea, 2-hydroxy-4,6-dichloro-1 , 3,5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. No. 3,017,280, US Pat. No. 2,983 Aziridine compounds as described in US Pat. No. 611, carbodiimide compounds as described in US Pat. No. 3,100,704 , Epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, borax, boric acid, borates There exist inorganic crosslinking agents etc., and these can be used 1 type or in combination of 2 or more types.

When using a partially saponified polyvinyl alcohol having a saponification degree of 80% or more as the hydrophilic binder, borax, boric acid and borates are preferred as the hardener, and boric acid is particularly preferred.

Further, a hydrophilic binder having a keto group can also be used as the hydrophilic binder constituting the image receiving layer A. The hydrophilic binder having a keto group can be synthesized by a method of copolymerizing a monomer having a keto group and another monomer. Specific examples of the monomer having a keto group include acrolein, diacetone acrylamide, diacetone methacrylate, acetoacetoxyethyl methacrylate, 4-vinylacetoacetanilide, acetoacetyl allylamide, and the like. Further, a keto group may be introduced by a polymer reaction. For example, an acetoacetyl group can be introduced by a reaction of a hydroxy group or an amino group with a diketene. Specific examples of the hydrophilic binder having a keto group include acetoacetyl-modified polyvinyl alcohol, acetoacetyl-modified cellulose derivatives, acetoacetyl-modified starch, diacetone acrylamide-modified polyvinyl alcohol, and hydrophilic binders described in JP-A-10-157283. Etc. In the present invention, modified polyvinyl alcohol having a keto group is particularly preferable. Examples of the modified polyvinyl alcohol having a keto group include acetoacetyl-modified polyvinyl alcohol and diacetone acrylamide-modified polyvinyl alcohol.

The acetoacetyl-modified polyvinyl alcohol can be produced by a known method such as a reaction between polyvinyl alcohol and diketene. The degree of acetoacetylation is preferably 0.1 to 20 mol%, more preferably 1 to 15 mol%. The saponification degree is preferably 80 mol% or more, more preferably 85 mol% or more. The polymerization degree is preferably 500 to 5000, and more preferably 2000 to 4500.

Diacetone acrylamide-modified polyvinyl alcohol can be produced by a known method such as saponification of diacetone acrylamide-vinyl acetate copolymer. The content of diacetone acrylamide units is preferably in the range of 0.1 to 15 mol%, more preferably in the range of 0.5 to 10 mol%. The saponification degree is preferably 85 mol% or more, and the polymerization degree is preferably 500 to 5000.

In the present invention, the hydrophilic binder having a keto group contained in the image receiving layer A is preferably crosslinked with a crosslinking agent. Examples of the crosslinking agent include the following compounds.

(1) Polyamines Aliphatic polyamines;
・ Alkylene diamine (for example, ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.)
-Polyalkylene polyamines (eg, diethylenetriamine, iminobis (propylamine), bis (hexamethylene) triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc.)
・ Substituents of these alkyl or hydroxyalkyl (for example, aminoethylethanolamine, methyliminobis (propylamine), etc.)
Aliphatic or heterocyclic-containing aliphatic polyamines (for example, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, etc.)
・ Aromatic ring-containing aliphatic amines (for example, xylylenediamine, tetrachloro-p-xylylenediamine, etc.)

C4-C15 alicyclic polyamines;
For example, 1,3-diaminocyclohexane, isophorone diamine, menthane diamine, 4,4'-methylene dicyclohexane diamine (hydrogenated methylene dianiline) and the like.

A C4-C15 heterocyclic polyamine;
For example, piperazine, N-aminoethylpiperazine, 1,4-diaminopiperazine and the like.

C6-C20 aromatic polyamines;
Unsubstituted aromatic polyamines (eg 1,2-, 1,3- and 1,4-phenylenediamine, 2,4'- and 4,4'-diphenylmethanediamine, polyphenylpolymethylenepolyamine, diaminodiphenylsulfone, benzidine Thiodianiline, bis (3,4-diaminophenyl) sulfone, 2,6-diaminopyridine, m-aminobenzylamine, triphenylmethane-4,4 ′, 4 ″ -triamine, naphthylenediamine, etc.)
Aromatic polyamines having a nucleus-substituted alkyl group (eg C1-C4 alkyl group) (eg 2,4- and 2,6-tolylenediamine, crude tolylenediamine, diethyltolylenediamine, 4,4'- Diamino-3,3'-dimethyldiphenylmethane, 4,4'-bis (o-toluidine), dianisidine, diaminoditolyl sulfone, 1,3-dimethyl-2,4-diaminobenzene, 1,3-diethyl-2, 4-diaminobenzene, 1,3-dimethyl-2,6-diaminobenzene, 1,4-diethyl-2,5-diaminobenzene, 1,4-diisopropyl-2,5-diaminobenzene, 1,4-dibutyl- 2,5-diaminobenzene, 2,4-diaminomesitylene, 1,3,5-triethyl-2,4-diaminobenzene, 1,3,5- Riisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 2,3-dimethyl- 1,4-diaminonaphthalene, 2,6-dimethyl-1,5-diaminonaphthalene, 2,6-diisopropyl-1,5-diaminonaphthalene, 2,6-dibutyl-1,5-diaminonaphthalene, 3,3 ′ , 5,5'-tetramethylbenzidine, 3,3 ', 5,5'-tetraisopropylbenzidine, 3,3', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3 ', 5,5′-tetraethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraisopropyl-4,4′-diaminodiphenylmethane, 3,3 ′, , 5'-Tetrabutyl-4,4'-diaminodiphenylmethane, 3,5-diethyl-3'-methyl-2 ', 4-diaminodiphenylmethane, 3,5-diisopropyl-3'-methyl-2', 4-diamino Diphenylmethane, 3,3'-diethyl-2,2'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3 ', 5,5'-tetraethyl-4,4'-diamino Benzophenone, 3,3 ', 5,5'-tetraisopropyl-4,4'-diaminobenzophenone, 3,3', 5,5'-tetraethyl-4,4'-diaminodiphenyl ether, 3,3 ', 5 5'-tetraisopropyl-4,4'-diaminodiphenyl sulfone, etc.)

Polyamide polyamines;
For example, low molecular weight (for example, molecular weight 200-5000) polyamide obtained by condensation of dicarboxylic acid (dimer acid, etc.) and excess (more than 2 moles per mole of acid) polyamines (the above-mentioned alkylene diamine, polyalkylene polyamine, etc.) Polyamines and the like.

Polyether polyamines;
For example, a hydride of a cyanoethylated polyether polyol (polyalkylene glycol, etc.) having a molecular weight of 100 to 5000.

(2) Dicyandiamide derivative;
Dicyandiamide, dicyandiamide / formalin polycondensate, dicyandiamide / diethylenetriamine polycondensate, etc.

(3) a hydrazine compound;
Inorganic salts of hydrazine, monoalkylhydrazine, hydrazine (for example, inorganic salts of hydrochloric acid, sulfuric acid, nitric acid, nitrous acid, phosphoric acid, thiocyanic acid, carbonic acid, etc.), organic salts of hydrazine (for example, organic salts of formic acid, oxalic acid, etc.) ).

(4) polyhydrazide compounds (dihydrazide, trihydrazide);
Carbohydrazide, succinic acid dihydrazide, adipic acid dihydrazide, citric acid trihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide and the like.

(5) Aldehydes;
Monoaldehyde such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, crotonaldehyde, benzaldehyde, glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, maleindialdehyde, 1,8-octane dial, phthalaldehyde, isophthalaldehyde , Terephthalaldehyde, dialdehydes such as aldehyde-terminated PVA, side chain aldehyde-containing copolymer obtained by saponifying arylidene acetate vinyl diacetate copolymer, dialdehyde starch, polyacrolein and the like.

(6) methylol compounds;
Methylolphosphine, dimethylolurea, dimethylolmelamine, trimethylolmelamine, urea resin initial polymer, melamine resin initial polymer, and the like.

(7) an activated vinyl compound;
Divinyl sulfone compounds, β-hydroxyethyl sulfone compounds, etc.

(8) epoxy compound;
Epichlorohydrin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diglycidyl amine, polyepoxy compounds, etc. .

(9) Isocyanate compounds;
Tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylenebis-4-phenylmethane triisocyanate, isophorone diisocyanate, and their ketoxime block or phenol block, poly Isocyanate and the like.

(10) phenolic compounds;
Phenol resin initial condensate, resorcinol resin, etc.

(11) a polyvalent metal salt;
・ Zirconium salt (zirconium nitrate, basic zirconium carbonate, zirconium acetate, zirconium sulfate, zirconium oxychloride, zirconium chloride, hydroxy zirconium chloride, zirconium carbonate, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium fluoride compound, etc.)
・ Titanium salts (titanium tetrachloride, titanium lactate, tetraisopropyl titanate, etc.)
・ Aluminum salts (aluminum chloride, aluminum sulfate, aluminum lactate, etc.)
・ Calcium salts (calcium chloride, calcium sulfate, calcium acetate, calcium propionate, etc.)
・ Magnesium salts (magnesium chloride, magnesium sulfate, etc.)
・ Zinc salts (zinc chloride, zinc sulfate, zinc acetate, etc.)

Among the above-mentioned crosslinking agents, polyhydrazide compounds and polyvalent metal salts are preferable. Among the polyhydrazide compounds, dihydrazide compounds are particularly preferable, and adipic acid dihydrazide and succinic acid dihydrazide are more preferable. As the polyvalent metal salt, a zirconium salt is particularly preferable, and zirconium oxychloride and zirconium nitrate are more preferable. The addition amount of the crosslinking agent is suitably in the range of 1 to 40% by weight, preferably in the range of 2 to 30% by weight, particularly preferably in the range of 3 to 20% by weight, based on the hydrophilic binder having a keto group. Moreover, since it has the same structure as ordinary polyvinyl alcohol except for the portion modified with acetoacetyl or diacetone acrylamide, a hardener can be used in combination. It is particularly preferable to use borax, boric acid, or borate in combination.

In the present invention, it is also possible to use a fully or partially saponified polyvinyl alcohol, a cation-modified polyvinyl alcohol, and a hydrophilic binder having a keto group. In that case, a hardening agent or a crosslinking agent may be used in combination. You can also.

In the present invention, other known hydrophilic binders may be used in combination. For example, cellulose derivatives such as carboxymethyl cellulose and hydroxypropyl cellulose, starch and various modified starches, gelatin and various modified gelatins, chitosan derivatives, carrageenan, casein, soy protein, polyvinyl alcohol and various modified polyvinyl alcohols, polyvinylpyrrolidone, polyacrylamide, etc. It can be used together as necessary. Furthermore, various latexes may be used in combination as a binder.

The content of the binder in the image receiving layer A is preferably in the range of 5 to 40% by mass, particularly preferably 10 to 30% by mass with respect to the inorganic fine particles mainly contained in the image receiving layer A. Thereby, a fine space | gap can be formed in an image receiving layer and a porous layer can be formed.

The dry coating amount of the image receiving layer A is preferably in the range of 10 to 50 g / m ² in terms of inorganic fine particles, more preferably in the range of 12 to 40 g / m ² , and particularly preferably in the range of 15 to 35 g / m ^2. . The image receiving layer A further includes a cationic polymer, an antiseptic, a surfactant, a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a pigment dispersant, an antifoaming agent, a leveling agent, a fluorescent whitening agent, Viscosity stabilizers, pH adjusters and the like can also be added.

The image receiving layer A and the image receiving layer B of the present invention may each be a single layer or a plurality of layers, and an intermediate layer may be provided between the image receiving layer A and the image receiving layer B.

(Water resistant support)
The water-resistant support used in the present invention includes polyester resins such as polyethylene terephthalate, diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, polyvinyl chloride, polyimide resins, cellophane, celluloid, and other plastic resin films, and paper. And a polyolefin resin-coated paper in which a polyolefin resin layer is coated on both sides of a base paper. These water-resistant supports have a thickness of 50 to 350 μm, preferably 80 to 300 μm.

Hereinafter, polyolefin resin-coated paper (hereinafter referred to as polyolefin resin-coated paper) as a water-resistant support will be described in detail. The water content of the polyolefin resin-coated paper used in the present invention is not particularly limited, but is preferably in the range of 5 to 9%, more preferably in the range of 6 to 9%. Thereby, the curl resulting from moisture absorption and moisture release can be suppressed small. The moisture content of the polyolefin resin-coated paper can be measured using any moisture measuring method. For example, an infrared moisture meter, an absolute dry weight method, a dielectric constant method, a Karl Fischer method, or the like can be used.

The base paper constituting the polyolefin resin-coated paper is not particularly limited, and commonly used paper can be used. More preferably, for example, smooth base paper used for a photographic support can be used. As the pulp constituting the base paper, natural pulp, regenerated pulp, synthetic pulp or the like is used alone or in combination. This base paper is blended with additives such as sizing agent, paper strength enhancer, filler, antistatic agent, fluorescent whitening agent, and dye generally used in papermaking. Further, a surface sizing agent, a surface paper strength agent, a fluorescent brightening agent, an antistatic agent, a dye, an anchor agent, and the like may be applied on the surface.

There is no particular limitation on the thickness of the base paper, but a paper having good surface smoothness such as a paper that is compressed during or after paper making by applying pressure with a calender or the like is preferable, and its basis weight is 30 to 250 g / m. ² is preferred.

Examples of the polyolefin resin for coating the base paper include homopolymers of olefins such as low-density polyethylene, high-density polyethylene, polypropylene, polybutene, and polypentene, or copolymers composed of two or more olefins such as ethylene-propylene copolymer, and the like. Of various densities and melt viscosity indices (melt index) can be used alone or as a mixture thereof.

In the resin of polyolefin resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, aluminum stearate, stearic acid Fatty acid metal salts such as magnesium, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue and phthalocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet and manganese purple, fluorescent brighteners, ultraviolet absorbers, etc. These various additives are preferably added in appropriate combination.

As a main production method of polyolefin resin-coated paper, it is produced by a so-called extrusion coating method in which a polyolefin resin is cast on a traveling base paper in a heated and melted state, and both surfaces of the base paper are covered with the resin. Further, before the resin is coated on the base paper, the base paper is preferably subjected to activation treatment such as corona discharge treatment and flame treatment. The thickness of the resin coating layer is suitably 5 to 50 μm.

(Undercoat layer)
An undercoat layer is preferably provided on the side of the water-resistant support on which the image receiving layer is provided. This undercoat layer is applied and dried in advance on the surface of the water-resistant support before the image-receiving layer is applied. This undercoat layer mainly contains a water-soluble polymer or polymer latex that can form a film. Preferred are water-soluble polymers such as gelatin, polyvinyl alcohol, polyvinyl pyrrolidone and water-soluble cellulose, and particularly preferred is gelatin. Adhesion amount of the water-soluble polymer is preferably 10 ~ 500mg / ^{m 2,} more preferably 20 ~ 300mg / ^{m 2.} Furthermore, it is preferable that the undercoat layer contains a surfactant and a hardener. By providing the undercoat layer on the support, it effectively works to prevent cracking when the image receiving layer is applied, and a uniform coated surface is obtained.

(Method for producing planographic printing plate precursor)
The lithographic printing plate precursor according to this embodiment can be produced by providing the image receiving layer A and the image receiving layer B on a water-resistant support. In the present invention, the coating method when providing the image receiving layer A and the image receiving layer B is not particularly limited, but a slide bead coater, curtain coater, extrusion coater, air knife coater, rod coater, blade coater, gravure coater, etc. The applicator can be used alone or in combination. When the image receiving layer A and the image receiving layer B are applied simultaneously, a slide bead coater or a curtain coater coating device can be used. In the case where the image receiving layer B is sequentially applied after the image receiving layer A is applied, the above application apparatuses can be used in appropriate combination. In the present invention, simultaneous application means that the respective layers are applied almost simultaneously. “Sequential coating” refers to coating the uppermost coating liquid after the voids of the image receiving layer are formed after the decreasing rate drying step.

[Embodiment 2: Planographic printing plate making method]
The lithographic printing plate making method according to the present embodiment is a lithographic printing plate making method characterized in that an aqueous pigment ink is printed on the lithographic printing plate precursor according to the first embodiment by an inkjet method. According to such a lithographic printing plate making method, direct plate making by an ink jet method is possible, it has excellent image quality, and it is possible to achieve both good printing durability and stain resistance. Note that the planographic printing plate precursor in the present embodiment basically has the same configuration and operational effects as those of the first embodiment, and therefore the description of the same contents as those of the first embodiment will be omitted as appropriate.

Examples of the ink used for printing image information on the image receiving layer of the lithographic printing plate precursor according to the present invention by an ink jet method include various inks such as water-based ink, solid ink, UV ink, and oil-based ink. However, since solid ink and UV ink have high ink viscosity at the time of ejection, it is difficult to eject fine ink droplets that enable high-resolution plate-making images. Oil-based inks are not suitable for office use because of the generation of vapors of non-aqueous solvents, and print images tend to bleed and it is difficult to obtain high-resolution plate-making images. Accordingly, water-based ink is preferable as the ink for printing on the lithographic printing plate precursor according to the invention. As such an aqueous ink, an aqueous pigment ink is particularly preferable. This makes it possible to obtain a high-resolution plate-making image and is suitable for office use.

As the aqueous pigment ink, an aqueous pigment ink containing a pigment and a styrene-acrylic copolymer resin or a styrene-methacrylic copolymer resin is preferably used.

Examples of the pigment include furnace black, lamp black, acetylene black, channel black, phthalocyanine pigment, quinacridone pigment, condensed azo pigment, isoindolinone pigment, quinophthalone pigment, anthraquinone pigment, benzimidazolone pigment, and perylene pigment. These pigments are preferably anionic pigments. Thereby, since the image receiving layer B of the present invention is cationic, it is firmly adhered to the surface of the image receiving layer by electrostatic interaction, and the printing durability is improved. The amount of pigment added is preferably 0.5 to 30% by mass in the aqueous ink.

When the water-based pigment ink contains a styrene-acrylic copolymer resin or a styrene-methacrylic copolymer resin, the affinity between the image area and the ink used during printing is improved, and the inking property to the ink is improved. . Such a resin may be water-soluble, or the resin may be a water-insoluble dispersion (emulsion). The amount of the resin added is preferably in the range of 0.1 to 20% by mass in the aqueous ink.

As monomers that can be incorporated into styrene-acrylic copolymer resins or styrene-methacrylic copolymer resins, styrene, 4-methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-carboxystyrene, 4-aminostyrene Styrene derivatives such as chloromethylstyrene and 4-methoxystyrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadodecyl methacrylate, etc. Methacrylic acid alkyl esters, phenyl methacrylate, methacrylic acid aryl esters such as benzyl methacrylate, or alkyl aryl esters, 2-hydroxyethyl methacrylate, Methacrylic acid esters having an alkyleneoxy group such as 2-hydroxypropyl crylate, methoxydiethylene glycol monoester methacrylate, methoxypolyethylene glycol monoester methacrylate, polypropylene glycol monoester methacrylate, 2-dimethylaminoethyl methacrylate, methacrylic acid Examples of amino group-containing methacrylic acid esters such as 2-diethylaminoethyl, and acrylic acid esters are the same as the corresponding methacrylic acid esters.

Styrene-acrylic copolymer resins or styrene-methacrylic copolymer resins include phosphoric acid group-containing monomers such as vinylphosphonic acid, amino group-containing monomers such as allylamine and diallylamine, vinyl sulfonic acid and Monomers having sulfonic acid groups such as salts thereof, allylsulfonic acid and salts thereof, methallylsulfonic acid and salts thereof, styrenesulfonic acid and salts thereof, 2-acrylamido-2-methylpropanesulfonic acid and salts thereof, or 4 Monomers having nitrogen-containing heterocycles such as -vinylpyridine, 2-vinylpyridine, N-vinylimidazole, N-vinylcarbazole, etc., or 4-vinylbenzyltrimethylammonium chloride, acryloyl as a monomer having a quaternary ammonium base Oxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, quaternized product of dimethylaminopropylacrylamide with methyl chloride, quaternized product of N-vinylimidazole with methyl chloride, 4-vinylbenzylpyridinium chloride, or acrylonitrile, methacrylo Nitrile, acrylamide or methacrylamide derivatives such as acrylamide, methacrylamide, dimethylacrylamide, diethylacrylamide, N-isopropylacrylamide, diacetoneacrylamide, N-methylolacrylamide, N-methoxyethylacrylamide, 4-hydroxyphenylacrylamide, and acrylonitrile , Methacrylonitrile, Lumaleimide, hydroxyphenylmaleimide, vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate and other vinyl esters, methyl vinyl ether, vinyl ethers such as butyl vinyl ether, and others, N-vinyl pyrrolidone Various monomers such as acryloylmorpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol, vinyltrimethoxysilane, and glycidyl methacrylate can be appropriately used as a copolymerization monomer.

“Water-based” of the water-based ink used when printing image information by the ink jet method means that the ink contains 50% by mass or more, more preferably 65% by mass or more of water. In some cases, a penetrant is added to the ink for the purpose of enhancing the penetrability into the image receiving layer. Further, a moisturizing agent and a dissolution aid are provided for the purpose of ensuring the standing stability and achieving stable ejection from the ink ejection head. Various additives such as a penetrating agent, a viscosity adjusting agent, a pH adjusting agent, an antioxidant, an antifungal agent, a corrosion inhibitor and a chelating agent can be added.

Examples of commercially available water-based inks containing the above copolymer resins include ICC59, ICM59, ICY59, ICBK59, ICC33, ICBL33, ICM33, ICY33, ICBK33, ICR33, ICC23, ICGY23, ICLC23, ICLM23, ICM23, ICY23, ICMB23, ICBK23 (manufactured by Seiko Epson Corporation), PFI-101C, PFI-101M, PFI-101Y, PFI-101R, PFI-101G, PFI-101B, PFI-101PC, PFI-101PM (manufactured by Canon Inc.) .

In this embodiment, it is preferable to perform a desensitization process on a non-image portion after printing image information on a planographic printing plate precursor by an ink jet method and before starting printing. Thereby, more favorable printability, stain resistance, and ink landing property can be obtained. The treatment liquid used for such desensitization treatment is described in, for example, JP-A-5-289341, JP-A-7-56349, JP-B 45-29001, JP-B 61-28987, and the like. And a treatment liquid containing colloidal fine particles and a hygroscopic polyol described in JP-B-56-41992. Application of these treatment liquids to the plate surface is a method of hand etching in which absorbent cotton or the like is impregnated with the treatment solution and applied all over the plate surface, a method of applying a certain amount of the treatment solution with a bar coater, For example, a method using an etching converter that is immersed in a stored liquid bath and squeezes excess treatment liquid with a roll pair can be applied.

Hereinafter, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples. In addition, a part represents the mass part of solid content or a substantial component.

[Preparation of lithographic printing plate precursor 1]
Example 1
<Production of water-resistant support>
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and hardwood bleached sulfite pulp (LBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. The sizing agent and alkyl ketene dimer were 0.5% by mass of pulp, 1% by mass of polyacrylamide as a strengthening agent, 1% by mass of cationized starch, 2% by mass of pulp, and polyamide epichlorohydrin resin by 0.1% of pulp. 5% by mass was added and diluted with water to give a 0.2% by mass slurry. This slurry was made with a long paper machine to a basis weight of 170 g / m ² , dried and conditioned to obtain a base paper for the support. A polyethylene resin composition in which 10% by mass of anatase-type titanium dioxide is uniformly dispersed with respect to a low density polyethylene resin having a density of 0.918 g / cm ³ is melted at 320 ° C. on the printed surface side of the base paper produced at a temperature of 200 m. The resin coating layer on the image receiving layer coating surface side was provided while cooling with a cooling roll that was extruded to a thickness of 30 μm per minute and processed with a finely roughened surface. On the opposite side to melt at similarly 320 ° C. The blend resin composition of the low density polyethylene resin 30 parts of a density 0.962 g / cm 70 parts high density polyethylene resin of ³ and a density 0.918 g / cm ^3, a thickness A resin coating layer was provided while cooling with a cooling roll to 25 μm.

After the high-frequency corona discharge treatment was performed on the image-receiving layer-coated surface side of the water-resistant support, the undercoat layer having the following composition was coated and dried so that the gelatin content was 50 mg / m ² .

The image-receiving layer A coating solution 1 having the following composition is coated on the water-resistant support with a slide bead coating device so that the solid content is 25 g / m ² , cooled at 5 ° C. for 30 seconds, and then at 40 ° C. and 10% RH. After drying to the end of drying, the image-receiving layer B coating solution 1 having the following composition was sequentially applied with a gravure coating device so that the solid content of colloidal silica was 0.1 g / m ² and dried at 50 ° C.

<Gas phase silica dispersion 1>
After adding 3 parts of dimethyldiallyl aluminum chloride homopolymer (molecular weight: 9000) and 100 parts of gas phase method silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) to water to prepare a preliminary dispersion, using a high-pressure homogenizer The gas phase method silica dispersion 1 having a solid content concentration of 20% by mass was prepared. In addition, the average secondary particle diameter of the vapor phase method silica measured by a laser diffraction / scattering type particle size distribution analyzer was 80 nm.

<Image receiving layer B coating solution 1>
Add 100 parts of Quartron PL-3L (Colloidal Silica manufactured by Fuso Chemical Industry Co., Ltd.) to water to prepare a 5% by mass solid content solution, and then stir 10 parts Takibine # 1500 (Taki) over about 10 minutes with stirring. Polyaluminum chloride aqueous solution manufactured by Kagaku Co., Ltd .; solid content concentration 23.5% by mass) was added to obtain cationic colloidal silica. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 1 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +45 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 35 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 1.5.

(Example 2)
A lithographic printing plate precursor of Example 2 was produced in the same manner as in Example 1 except that the image-receiving layer A coating liquid 1 of Example 1 was changed to the image-receiving layer A coating liquid 2.

<Wet process silica dispersion 1>
Dimethyldiallylammonium chloride homopolymer (molecular weight 9000, 4 parts) and precipitated silica (nip seal VN3, specific surface area 210 m ² / g, average secondary particle size 23 μm, 100 parts) are added to water, and sawtooth blade type dispersion A preliminary dispersion was prepared using a machine (blade peripheral speed 30 m / sec). Next, the obtained preliminary dispersion was passed through a bead mill once under the conditions of 0.3 mm diameter zirconia beads, a filling rate of 80% by volume, and a disk peripheral speed of 10 m / second, and a wet method with a solid content concentration of 30% by mass. Silica dispersion 1 was obtained. In addition, the average secondary particle diameter of the wet method silica measured by a laser diffraction / scattering type particle size distribution analyzer was 200 nm.

(Example 3)
A lithographic printing plate precursor of Example 3 was produced in the same manner as in Example 1 except that the image-receiving layer A coating solution 1 in Example 1 was changed to the image-receiving layer A coating solution 3. The average secondary particle diameter of the alumina hydrate as measured with a laser diffraction / scattering particle size distribution analyzer was 160 nm.

Example 4
A lithographic printing plate precursor of Example 4 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 2.

<Image receiving layer B coating solution 2>
Add 100 parts Quortron PL-5 (colloidal silica manufactured by Fuso Chemical Co., Ltd.) to water to prepare a 5% by mass solid content solution, and then stir 10 parts Takibine # 1500 (Taki) over about 10 minutes with stirring. A polyaluminum chloride aqueous solution manufactured by Chemical Co., Ltd .; solid content concentration 23.5% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 2 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +47 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 52 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 2.2.

(Example 5)
A lithographic printing plate precursor of Example 5 was prepared in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 3.

<Image receiving layer B coating solution 3>
Add 100 parts of Quartron PL-3L (colloidal silica manufactured by Fuso Chemical Industry Co., Ltd.) to water to prepare a 5% by mass solid content solution, and then stir 10 parts of ZA-30 (1st over about 10 minutes with stirring). Zirconyl acetate manufactured by Rare Elemental Chemical Co., Ltd .; solid content concentration of 30% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 3 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +43 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 35 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 1.5.

(Example 6)
A lithographic printing plate precursor of Example 6 was prepared in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 4.

<Image receiving layer B coating solution 4>
An apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel was charged with 100 parts of Quattron PL-3L (colloidal silica manufactured by Fuso Chemical Co., Ltd .: solid content concentration: 20% by mass) and heated to 75 ° C. . Next, while maintaining at 75 ° C. with stirring, 5 parts of N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane was added dropwise over 15 minutes, and the reaction was carried out by keeping the temperature at the same temperature for 30 minutes or more. This was cooled and a cationic colloidal silica treated with a coupling agent was prepared and adjusted with water so that the solid content concentration was 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 4 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +42 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 35 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 1.5.

(Example 7)
A lithographic printing plate precursor of Example 7 was prepared in the same manner as in Example 1 except that the amount of the colloidal silica solid content in the image-receiving layer B coating solution 1 of Example 1 was changed to 0.3 g / m ² .

(Example 8)
A lithographic printing plate precursor of Example 8 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 5.

<Image receiving layer B coating solution 5>
100 parts of Cataloid SI-50 (JGC Catalysts & Chemicals Co., Ltd. colloidal silica) was added to water to prepare a 5% by mass solid content solution, and then stirred with 10 parts of tachyvine # 1500 (Taki) over about 10 minutes. A polyaluminum chloride aqueous solution manufactured by Chemical Co., Ltd .; solid content concentration 23.5% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 5 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +42 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 25 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 1.2.

Example 9
A lithographic printing plate precursor of Example 9 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 6.

<Image receiving layer B coating solution 6>
Add 100 parts of Quartron PL-7 (colloidal silica manufactured by Fuso Chemical Industry Co., Ltd.) to water to prepare a 5% by mass solid content solution, and then stir and stir 10 parts Takibine # 1500 (Taki) over about 10 minutes. A polyaluminum chloride aqueous solution manufactured by Chemical Co., Ltd .; solid content concentration 23.5% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 6 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +38 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 70 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 1.7.

(Example 10)
A lithographic printing plate precursor of Example 10 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 7.

<Image receiving layer B coating solution 7>
Add 100 parts of Quartron PL-1 (colloidal silica manufactured by Fuso Chemical Co., Ltd.) to water to prepare a 5% by mass solid content solution, and then stir and stir 10 parts of tachyvine # 1500 (Taki) over about 10 minutes. A polyaluminum chloride aqueous solution manufactured by Chemical Co., Ltd .; solid content concentration 23.5% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 7 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +38 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 15 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 2.7.

(Example 11)
A lithographic printing plate precursor of Example 11 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 8.

<Image receiving layer B coating solution 8>
Add 100 parts of Snowtex ST-PS-M (Nissan Chemical Co., Ltd. colloidal silica) to the water to prepare a 5% by weight solid content solution, and then stir 10 parts of tachyvine # 1500 over about 10 minutes with stirring. (A polyaluminum chloride aqueous solution manufactured by Taki Chemical Co., Ltd .; solid content concentration 23.5% by mass) was added. After completion of the addition, the mixture was stirred at a temperature of 80 ° C. for 1 hour, cooled to room temperature, and adjusted with water so that the solid content concentration became 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 8 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +38 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 35 nm, and the ratio of the average secondary particle diameter to the average primary particle diameter was 4.0.

(Example 12)
A lithographic printing plate precursor of Example 12 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the image-receiving layer B coating solution 9 described below.

<Image receiving layer B coating solution 9>
100 parts of fine cataloid C-125 (colloidal silica manufactured by JGC Catalysts and Chemicals Co., Ltd.) was added to water, and the solid content concentration was adjusted to 0.6% by mass. As a result of measuring the zeta potential of the prepared image-receiving layer B coating solution 9 with a zeta potential measuring device (DELSA 440SX manufactured by Beckman Coulter, Inc.), it was +45 mV. Moreover, the average primary particle diameter of the cationic colloidal silica by electron microscope observation was 20 nm, and secondary particles were not recognized.

(Example 13)
A lithographic printing plate precursor of Example 13 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was changed to the following image-receiving layer B coating solution 10. When observed with an electron microscope, secondary particles were not observed in the colloidal silica in the image-receiving layer B coating solution 10.

(Example 14)
A lithographic printing plate precursor of Example 14 was produced in the same manner as in Example 1 except that the image-receiving layer A coating liquid 1 of Example 1 was changed to the following image-receiving layer A coating liquid 4.

<Wet method silica dispersion 2>
Dimethyldiallylammonium chloride homopolymer (molecular weight 9000, 4 parts) and precipitated silica (nip seal VN3, specific surface area 210 m ² / g, average secondary particle size 23 μm, 100 parts) are added to water, and sawtooth blade type dispersion A preliminary dispersion was prepared using a machine (blade peripheral speed 30 m / sec). Next, the obtained pre-dispersion was passed through a bead mill once under the conditions of a zirconia bead having a diameter of 0.3 mm, a filling rate of 70% by volume, and a disk peripheral speed of 8.0 m / sec. Wet process silica dispersion 2 was obtained. In addition, the average secondary particle diameter of the wet method silica as measured with a laser diffraction / scattering particle size distribution analyzer was 800 nm.

(Example 15)
On the undercoat layer of the water-resistant support produced in Example 1, the image-receiving layer A coating solution 1 obtained in Example 1 and the image-receiving layer B coating solution 11 described below were used using a slide bead coating device. The image receiving layer A was applied in multiple layers so that the solid content of the image receiving layer A was 25 g / m ² and the solid content of the image receiving layer B was 1.0 g / m ² , and then cooled at 5 ° C. for 30 seconds and then at 40 ° C. and 10% RH. Dried to the end of drying.

(Example 16)
A lithographic printing plate precursor of Example 16 was produced in the same manner as in Example 15 except that the image receiving layer B coating solution 11 used in Example 15 was changed to the following image receiving layer B coating solution 12.

(Example 17)
The following image receiving layer A coating solution 5 and image receiving layer B coating solution 11 prepared in Example 15 are applied to the undercoat layer of the water-resistant support prepared in Example 1 using a slide bead coating device. The image receiving layer A has a solid content of 25 g / m ² and the image receiving layer B has a solid content of 1.0 g / m ^2, and after cooling at 5 ° C. for 30 seconds, 40 ° C. and 10% RH And dried to the end of drying.

<Gas phase method silica dispersion 2>
After adding 4 parts of dimethyldiallyl aluminum chloride homopolymer (molecular weight: 9000) and 100 parts of gas phase method silica (average primary particle diameter of 7 nm, specific surface area of 400 m ² / g) to water to prepare a preliminary dispersion, a high-pressure homogenizer was used. The gas phase method silica dispersion 2 having a solid content concentration of 20% by mass was prepared. In addition, the average secondary particle diameter of the vapor phase method silica measured by a laser diffraction / scattering type particle size distribution analyzer was 80 nm.

(Example 18)
On the undercoat layer of the water-resistant support prepared in Example 1, the image receiving layer A coating solution 6 described below and the image receiving layer B coating solution 11 prepared in Example 15 were used using a slide bead coating apparatus. The image receiving layer A has a solid content of 25 g / m ² and the image receiving layer B has a solid content of 1.0 g / m ^2, and after cooling at 5 ° C. for 30 seconds, 40 ° C. and 10% RH And dried to the end of drying.

<Gas phase method silica dispersion 3>
After adding 3 parts of dimethyldiallyl aluminum chloride homopolymer (molecular weight: 9000) and 100 parts of gas phase method silica (average primary particle diameter 12 nm, specific surface area 200 m ² / g) to water to prepare a preliminary dispersion, using a high-pressure homogenizer The gas phase method silica dispersion 3 having a solid content concentration of 20% by mass was prepared. In addition, the average secondary particle diameter of the vapor phase method silica measured by a laser diffraction / scattering type particle size distribution analyzer was 80 nm.

(Comparative Example 1)
A lithographic printing plate precursor of Comparative Example 1 was produced in the same manner as in Example 1 except that the image-receiving layer B coating solution 1 of Example 1 was not applied.

(Comparative Example 2)
A planographic printing plate precursor of Comparative Example 2 was prepared in the same manner as in Example 2 except that the image receiving layer B coating solution 1 of Example 2 was not applied.

(Comparative Example 3)
A lithographic printing plate precursor of Comparative Example 3 was produced in the same manner as in Example 3 except that the image-receiving layer B coating solution 1 of Example 3 was not applied.

(Comparative Example 4)
A lithographic printing plate precursor of Comparative Example 4 was produced in the same manner as Comparative Example 1, except that the image receiving layer A coating liquid 1 of Comparative Example 1 was changed to the image receiving layer A coating liquid 7.

(Comparative Example 5)
A lithographic printing plate precursor of Comparative Example 5 was prepared in the same manner as Comparative Example 1 except that the image receiving layer A coating liquid 1 of Comparative Example 1 was changed to the following image receiving layer A coating liquid 8.

<Image receiving layer A coating solution 8>
Vapor phase silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) 50 g was dispersed in 500 g of ion exchange water with a stirrer, and 10% by mass of polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500). 80 g of an aqueous solution was mixed. Furthermore, 250 g of colloidal silica (Snowtex-O manufactured by Nissan Chemical Industries, Ltd .; solid content concentration 20% by mass) having an average primary particle size of 10 to 20 nm and spherical primary particles being colloidal particles, and 21 with respect to the polyvinyl alcohol. After mixing mass% boric acid, the mixture was uniformly dispersed in a homomixer at 10,000 rpm for 10 minutes to obtain an image receiving layer A coating solution 8.

(Comparative Example 6)
A lithographic printing plate precursor of Comparative Example 6 was prepared in the same manner as in Example 1 except that the image receiving layer B coating solution 1 of Example 1 was changed to the following image receiving layer B coating solution 13.

<Image receiving layer B coating solution 13>
Add 100 parts of Quartron PL-3L (colloidal silica manufactured by Fuso Chemical Industries; average primary particle diameter of 35 nm, colloidal particles are non-spherical particles) to water and dilute to a solid content concentration of 5% by mass. An image receiving layer B coating solution 13 was obtained.

(Comparative Example 7)
A lithographic printing plate precursor of Comparative Example 7 was prepared in the same manner as in Example 1 except that the image receiving layer B coating solution 1 of Example 1 was changed to the following image receiving layer B coating solution 14.

<Image receiving layer B coating solution 14>
Add 100 parts of Cataloid SI-50 (Colloidal Silica manufactured by JGC Catalysts &Chemicals; average primary particle diameter of 25 nm and spherical primary particles are colloidal particles) to water and dilute to a solid content concentration of 5% by mass. Thus, an image receiving layer B coating solution 14 was obtained.

(Comparative Example 8)
A lithographic printing plate precursor of Comparative Example 8 was produced in the same manner as in Example 15 except that the image receiving layer B coating solution 11 of Example 15 was changed to the following image receiving layer B coating solution 15.

[Plate printing plate making 1]
For each lithographic printing plate precursor produced as described above, an image is recorded (cyan ink) using an ink jet printer (PX-1001 manufactured by Seiko Epson Corporation) using an aqueous pigment ink, and a lithographic printing plate is produced. did.

[Evaluation Method 1]
<Image quality>
The sharpness of the image boundary of the recorded image was visually observed. Evaluation was made according to the following criteria. The results are shown in Table 1.
○: Very sharp and no blurring at the boundary.
Δ: Level at which slight blur is observed but does not cause a problem.
X: The blur at the boundary is remarkable and the ink absorbability is inferior.

<Print durability>
A printing test was performed using the planographic printing plate on which an image was recorded as described above. The printing machine uses HAMADA DU34II (offset printing machine manufactured by Hamada Printing Machinery Co., Ltd.), the ink is New Champion F gloss ink 85N (manufactured by DIC Corporation), and the dampening liquid is SLM-OD (humidity supplied by Mitsubishi Paper Industries Co., Ltd.). Use a 25% by weight aqueous solution of SLM-OD30 (Mitsubishi Paper Co., Ltd., moisturizing liquid: containing colloidal silica and butyltriglycol) before commencing printing. After the desensitization treatment, printing was started, and the number of prints that could not be printed due to missing images was evaluated according to the following evaluation criteria. The results are shown in Table 1.
◎: 7,000 or more ◎: 5,000 or more and less than 7,000 ○: 3,000 or more and less than 5,000 △: 1,000 or more and less than 3,000 ×: less than 1,000

<Stain resistance>
Using the lithographic printing plate on which the image was recorded as described above, the same as when the printing durability was evaluated except that the dampening solution was replaced with a 0.5% by mass aqueous solution of Toho H (Toho Seiki Co., Ltd.) A printing test was performed under the printing conditions, and the number of stains (background stains) generated on the non-image portion of the printed material was evaluated according to the following evaluation criteria. The results are shown in Table 1.
◎: 3,000 or more ◎: 2,000 or more and less than 3,000 sheets ○: 1,500 or more and less than 2,000 sheets △: 1,000 or more and less than 1,500 sheets ×: Less than 1,000 sheets

[Preparation of lithographic printing plate precursor 2]
(Example 19)
A lithographic printing plate precursor of Example 19 was produced in the same manner as in Example 16 except that the image-receiving layer B coating solution 12 used in Example 16 was replaced with the image-receiving layer B coating solution 16 described below.

(Example 20)
A lithographic printing plate precursor of Example 20 was produced in the same manner as in Example 16 except that the image-receiving layer B coating solution 12 used in Example 16 was changed to the image-receiving layer B coating solution 17 described below.

(Example 21)
A lithographic printing plate precursor of Example 21 was produced in the same manner as in Example 16 except that the image receiving layer B coating solution 12 used in Example 16 was changed to the image receiving layer B coating solution 18 described below.

(Example 22)
A lithographic printing plate precursor of Example 22 was produced in the same manner as in Example 16 except that the image receiving layer B coating solution 12 used in Example 16 was changed to the image receiving layer B coating solution 19 shown below.

(Example 23)
A lithographic printing plate precursor of Example 23 was produced in the same manner as in Example 13 except that the image-receiving layer B coating solution 10 of Example 13 was changed to the image-receiving layer B coating solution 20 shown below. When observed with an electron microscope, secondary particles were not observed in the colloidal silica in the image-receiving layer B coating solution 20.

(Example 24)
A lithographic printing plate precursor of Example 24 was produced in the same manner as in Example 13 except that the image-receiving layer B coating solution 10 of Example 13 was changed to the following image-receiving layer B coating solution 21. When observed with an electron microscope, secondary particles were not observed in the colloidal silica in the image-receiving layer B coating solution 21.

(Example 25)
A lithographic printing plate precursor of Example 25 was produced in the same manner as in Example 13 except that the image receiving layer B coating solution 10 of Example 13 was changed to the following image receiving layer B coating solution 22. When observed with an electron microscope, secondary particles were not observed in the colloidal silica in the image-receiving layer B coating solution 22.

[Plate printing plate making 2]
For each of the lithographic printing plate precursors of Examples 19 to 25 produced as described above, an image was recorded using an ink jet printer (PX-1001 manufactured by Seiko Epson Corporation) using an aqueous pigment ink (cyan ink). A lithographic printing plate was prepared.

[Evaluation Method 2]
<Image quality>
The sharpness of the image boundary of the recorded image was visually observed according to the same evaluation criteria as in the evaluation method 1 <image quality>. The results are shown in Table 2.

<Print durability>
Printing was started in the same manner as in the evaluation method 1 <printing durability>, and the number of prints that could not be printed due to missing images was evaluated according to the same evaluation criteria. The results are shown in Table 2.

<Stain resistance>
Printing was started in the same manner as in the above evaluation method 1 <stain resistance>, and the number of stains (background stains) on the non-image area of the printed material was evaluated according to the following evaluation criteria. The results are shown in Table 2.
◎◎◎: 4,000 or more ◎◎: 3,000 or more and less than 4000 ◎: 2,000 or more and less than 3,000 ○: 1,500 or more and less than 2,000 △: 1,000 or more, 1,500 Less than ×: Less than 1,000 sheets

[Preparation of planographic printing plate precursor 3]
The lithographic printing plate precursor of Example 16 was prepared as a lithographic printing plate precursor (A), and the lithographic printing plate precursor of Comparative Example 1 was prepared as a lithographic printing plate precursor (C). Further, the following lithographic printing plate precursor (B), lithographic printing plate precursor (D), and lithographic printing plate precursor (E) were prepared.

<Preparation of lithographic printing plate precursor (B)>
On the undercoat layer of the water-resistant support produced in Example 1, the image receiving layer A coating liquid 1 of Example 1 and the image receiving layer B coating liquid 10 of Example 13 were used using a slide bead coating apparatus. The solid layer of the image receiving layer A is 25 g / m ² and the colloidal silica solid content of the image receiving layer B is 1 g / m ^2, and after cooling at 5 ° C. for 30 seconds, 40 ° C. and 10% RH And dried to the end point of drying to prepare a lithographic printing plate precursor (B).

<Preparation of lithographic printing plate precursor (D)>
On the undercoat layer of the water-resistant support produced in Example 1, the image receiving layer A coating solution 1 of Example 1 and the image receiving layer B coating solution 13 of Comparative Example 6 were used using a slide bead coating device. The image receiving layer A was applied in multiple layers so that the solid content of the image receiving layer A was 25 g / m ² and the solid content of the colloidal silica of the image receiving layer B was 1 g / m ² , and then cooled at 5 ° C. for 30 seconds and then at 40 ° C. and 10% RH. A lithographic printing plate precursor (D) was prepared by drying to the end of drying.

<Preparation of lithographic printing plate precursor (E)>
On the undercoat layer of the water-resistant support prepared in Example 1, the following polymer type image receiving layer coating solution was applied with a slide bead coating device so that the solid content was 2 g / m ² , and at 140 ° C. for 10 minutes. The lithographic printing plate precursor (E) was prepared by drying.

[Plate printing plate making 3]
<Preparation of water-based pigment ink>
An aqueous pigment ink containing a pigment having the following composition and a styrene-acrylic copolymer resin or a styrene-methacrylic copolymer resin was prepared.

<Water-based pigment ink>

Images were recorded on the lithographic printing plate precursors A to E produced as described above using an ink jet printer with the combinations of aqueous pigment inks 1 to 10 described in Table 3.

[Evaluation Method 3]
<Image quality>
The sharpness of the image boundary of the recorded image was visually observed according to the same evaluation criteria as in the evaluation method 1 <image quality>. The results are shown in Table 4.

<Print durability>
Printing was started in the same manner as in the above evaluation method 1 <print durability>, and the number of prints that could not be printed due to missing images was evaluated according to the same evaluation criteria as in evaluation method 1 <print durability>. The results are shown in Table 4.

<Stain resistance>
Printing is started in the same manner as in the evaluation method 1 <stain resistance>, and the number of stains (background stains) generated on the non-image portion of the printed material is evaluated based on the same evaluation criteria as in the evaluation method 1 <stain resistance>. did. The results are shown in Table 4.

<Ink fillability>
Using the planographic printing plate on which the image was recorded as described above, the printing machine was Heidelberg TOK (trademark of Heidelberg's offset printing machine), the ink was BEST ONE Ink H (T & KTOKA Co., Ltd.), wet The shimizu was evaluated using a 1% by mass aqueous solution of Astro Mark 3 (dampening water manufactured by Nikken Chemical Research Co., Ltd.). The number of printed sheets until the ink was completely deposited on the flat mesh portion of the printed image was counted. The smaller the number of sheets, the better the ink deposition property. The results are shown in Table 4.

From the results of Tables 1, 2 and 4, a lithographic plate capable of direct plate making by an ink jet method according to the present invention, having excellent image quality and having both good printing durability and stain resistance. It can be seen that a printing plate precursor can be obtained.

The present invention has been described based on the embodiments. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

Claims

An image-receiving layer A mainly containing inorganic fine particles on a water-resistant support, and containing cationic colloidal silica mainly on the side farther from the water-resistant support than the image-receiving layer A or colloidal A lithographic printing plate precursor comprising an image receiving layer B mainly containing silica and containing a cationic compound.
2. The planographic plate according to claim 1, wherein the image receiving layer B is a layer mainly containing cationic colloidal silica having an average primary particle diameter of 30 nm or more or mainly containing non-spherical cationic colloidal silica. A printing plate master.
The non-spherical cationic colloidal silica has an average primary particle diameter of 25 to 60 nm and a ratio of an average secondary particle diameter to an average primary particle diameter of 1.4 to 3.1. Lithographic printing plate precursor.
The lithographic printing plate precursor according to claim 2, wherein the image receiving layer B is a layer mainly containing cationic colloidal silica having an average primary particle diameter of 30 nm or more.
The lithographic printing plate precursor according to claim 4, wherein the image receiving layer B is a layer mainly containing cationic colloidal silica having an average primary particle diameter of 50 nm or more.
The lithographic printing plate precursor according to claim 1, wherein the image receiving layer B contains polyvinyl alcohol and a cellulose derivative.
The lithographic printing plate precursor as claimed in any one of Claims 1 to 6, wherein the inorganic fine particles contained in the image receiving layer A are inorganic fine particles having a specific surface area of more than 150 m 2 / g as measured by a BET method.
The lithographic printing plate precursor according to claim 7, wherein the inorganic fine particles contained in the image receiving layer A are vapor phase method silica having a specific surface area by BET method of more than 300 m 2 / g.
A method for making a lithographic printing plate, comprising printing an aqueous pigment ink on the lithographic printing plate precursor according to any one of claims 1 to 8 by an inkjet method.
The lithographic printing plate making method according to claim 9, wherein the aqueous pigment ink is an aqueous pigment ink containing a pigment and a styrene-acrylic copolymer resin or a styrene-methacrylic copolymer resin.
The method for making a lithographic printing plate according to claim 9 or 10, comprising a desensitizing treatment after printing the aqueous pigment ink on the lithographic printing plate precursor and before starting printing.