JP6466356B2 - Printing method - Google Patents

Description

  The present invention relates to a printing method. More specifically, the present invention relates to a printing method including a step of on-machine development of an on-press development type lithographic printing plate precursor and an on-press development type lithographic printing plate dummy plate.

  In general, a lithographic printing plate is composed of an oleophilic image area that receives ink and a hydrophilic non-image area that receives dampening water in the printing process. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.

  At present, in a plate making process for producing a lithographic printing plate from a lithographic printing plate precursor, image exposure is performed by a CTP (computer to plate) technique. That is, the image exposure is performed by scanning exposure or the like directly on the lithographic printing plate precursor using a laser or a laser diode without using a lith film.

  In addition, due to the growing interest in the global environment, environmental issues related to waste liquids associated with wet processing such as development processing have been highlighted in relation to plate making of lithographic printing plate precursors, and as a result, development processing has been simplified or eliminated. It is oriented. As one simple development process, a method called “on-press development” has been proposed. On-press development is a method in which, after image exposure of a lithographic printing plate precursor, conventional development processing is not performed, but it is directly attached to a printing press and unnecessary portions of the image recording layer are removed at the initial stage of a normal printing process.

Under such circumstances, development of a lithographic printing plate precursor (hereinafter also referred to as an on-machine development type lithographic printing plate precursor) that can cope with on-press development has been carried out, and the image recording layer of the on-press development type lithographic printing plate precursor has been developed. For the purpose of accelerating the image forming reaction, it has been proposed to contain a polymerization initiator containing an organic boron-containing anion in the image recording layer (see Patent Document 1).
However, it has been found that an on-press development type lithographic printing plate precursor having an image recording layer containing a polymerization initiator containing an organic boron-containing anion has a problem that on-press developability deteriorates during storage.

  On the other hand, in the field of multi-color printing such as color newspaper printing, when it is necessary to print a part of paper with two colors or one color, a part that does not require printing on a printing cylinder In some cases, a dummy plate is attached instead of the printing plate for printing. As a material for making such a dummy plate (sometimes called a discarded plate, a water plate, or a blank plate), Patent Document 2 discloses a non-photosensitive layer and a hydrophilic layer in this order on an aluminum support. A lithographic printing plate discard plate precursor containing a coloring agent having an absorption maximum at 350 to 550 nm in a non-photosensitive layer and / or a hydrophilic layer and a matting agent in a hydrophilic layer is described.

WO2008 / 150441 JP 2012-116165 A

  The problem to be solved by the present invention is an on-press development process for preventing a reduction in on-press developability in an on-press development type lithographic printing plate precursor having an image recording layer containing a polymerization initiator containing an organic boron-containing anion. It is to provide a printing method including.

The present inventor has found that the above-mentioned problems can be solved by using an on-press development type lithographic printing plate dummy plate having a constituent layer containing a low molecular weight hydrophilic compound on an aluminum support, and the present invention. It came to complete.
The present invention includes the following configurations.

(1) An on-press development type lithographic plate having at least one constituent layer on an aluminum support and mounted on the same plate cylinder of a printing press, wherein at least one constituent layer contains a low molecular weight hydrophilic compound. A printing method comprising the steps of on-press development of a printing plate dummy plate and an on-press development type lithographic printing plate precursor having an image recording layer containing a polymerization initiator containing an organic boron-containing anion on an aluminum support.
(2) Of the above constituent layers, the constituent layer in contact with the aluminum support contains a water-soluble polymer compound containing a repeating unit having a support adsorptive group and a repeating unit having a hydrophilic group. The printing method described.
(3) The water-soluble polymer compound is a monomer unit having at least one group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, and salts thereof, a sulfonic acid group, a salt thereof, an amide group, and betaine. The printing method according to (2), which is a copolymer comprising at least one group selected from the structure or a monomer unit having a structure.
(4) The printing method according to any one of (1) to (3), wherein the low molecular weight hydrophilic compound is a surfactant.
(5) The printing method according to (4), wherein the surfactant is a sulfonate anionic surfactant.
(6) The printing method according to any one of (1) to (5), wherein at least one of the constituent layers contains fine particles.
(7) The printing method according to any one of (1) to (6), wherein at least one of the constituent layers contains a colorant having an absorption maximum at 350 to 800 nm.
(8) The printing method according to any one of (1) to (7), wherein the on-press development type lithographic printing plate dummy plate has two constituent layers.
(9) The printing method according to any one of (1) to (7), wherein the on-press development type lithographic printing plate dummy plate has three layers.
(10) The printing method according to any one of (1) to (9), wherein the polymerization initiator is an iodonium compound containing an organic boron-containing anion and a diaryl iodonium cation.
(11) The printing method according to any one of (1) to (10), wherein the image recording layer contains polymer fine particles.
(12) The printing method according to (11), wherein the polymer fine particles are copolymer particles containing styrene and acrylonitrile.
(13) The printing method according to (11), wherein the polymer fine particle is a microgel.
(14) The printing method according to any one of (1) to (13), wherein the on-press development type lithographic printing plate precursor has an undercoat layer between the aluminum support and the image recording layer.
(15) The printing method according to any one of (1) to (14), wherein the on-press development type lithographic printing plate precursor has a protective layer on the image recording layer.

  According to the present invention, there is provided a printing method including an on-press development step for preventing a reduction in on-press developability in an on-press development type lithographic printing plate precursor having an image recording layer containing a polymerization initiator containing an organic boron-containing anion. Can be provided.

It is a side view which shows the concept of the process of the brush graining used for the mechanical surface roughening process in manufacture of an on-machine development type lithographic printing plate dummy plate and a support for an on-machine development type lithographic printing plate precursor. It is a side view which shows an example of the radial type cell used for the electrochemical roughening process using alternating current in manufacture of the support body for on-press development type lithographic printing plate dummy plates and an on-press development type lithographic printing plate precursor. It is the schematic of the anodizing apparatus used for the anodizing process in manufacture of an on-press development type lithographic printing plate dummy plate and an on-press development type lithographic printing plate precursor support.

  Hereinafter, the present invention will be described in detail.

[On-press development type lithographic printing plate dummy]
The on-press development type lithographic printing plate dummy plate used in the printing method according to the present invention has at least one constituent layer on an aluminum support and contains a low molecular weight hydrophilic compound in at least one constituent layer. Yes.

[Aluminum support]
The on-press development type lithographic printing plate dummy plate has an aluminum support. As the aluminum support for the on-press development type lithographic printing plate dummy plate, known aluminum supports (including aluminum alloy supports) used for lithographic printing plate precursors are used. Among these, an aluminum plate that has been roughened and anodized by a known method is preferably used.
For the roughening treatment and anodizing treatment, for example, an aluminum support for a lithographic printing plate precursor described in JP-A-2014-198453, paragraphs [0045]-[0064] and [0069]-[0077] A roughening treatment and anodizing treatment applied to the body can also be used.
For the aluminum plate, if necessary, the micropore enlargement treatment and sealing treatment of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365, and US Pat. Alkali metal silicates or US patents as described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734 The surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each specification of 3,276,868, 4,153,461 and 4,689,272 is appropriately selected. It can be carried out.
The aluminum support preferably has a center line average roughness of 0.10 to 1.2 μm.

  If necessary, the aluminum support may have a back surface containing an organic polymer compound described in JP-A-5-45885 or a silicon alkoxy compound described in JP-A-6-35174. A coat layer can be provided.

  The on-press development type lithographic printing plate dummy plate has one, two or three constituent layers on an aluminum support. The constituent layer is preferably water-dispersible or water-soluble from the viewpoint of on-press development suitability. Further, at least one of the constituent layers contains a low molecular weight hydrophilic compound.

<Low molecular hydrophilic compound>
The low molecular weight hydrophilic compound contained in at least one of the constituent layers of the on-press development type lithographic printing plate dummy plate (hereinafter sometimes simply referred to as lithographic printing plate dummy plate) is dissolved in the dampening water supplied during printing. And a compound having an action of adhering to an on-press development type lithographic printing plate precursor (hereinafter sometimes simply referred to as “lithographic printing plate precursor”) and enhancing water penetration into the image recording layer to promote on-press development. is there.
In light of solubility in dampening water, the molecular weight of the low molecular weight hydrophilic compound is preferably 5000 or less, more preferably 3000 or less, and even more preferably 1000 or less. The molecular weight of the low molecular weight hydrophilic compound is usually 100 or more.

  As the low molecular weight hydrophilic compound, a surfactant can be preferably used from the viewpoint of enhancing water permeability to the image recording layer. Examples of the surfactant include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant, and an anionic surfactant or a nonionic surfactant is preferable.

Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene aryl ether sulfate esters, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkylsulfosuccinic acid monoamide disodium salts, Petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxyethylene alkyl -Ter sulfate, fatty acid monoglyceride sulfate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene styrylphenyl ether sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkylphenyl Examples thereof include ether phosphoric acid ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. Among these anionic surfactants, dialkyl sulfosuccinates, alkyl sulfate esters, polyoxyethylene aryl ether sulfate salts, and alkyl naphthalene sulfonates are particularly preferably used.
Specific examples include an anionic surfactant represented by the following formula (IA) or formula (IB).

In the above formula (IA), R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms, p represents 0, 1 or 2, and Ar ₁ has 6 to 10 carbon atoms. Represents an aryl group, q represents 1, 2 or 3, and M ₁ ⁺ represents Na ⁺ , K ⁺ , Li ⁺ or NH ₄ ⁺ . When p is 2, a plurality of R ₁ may be the same as or different from each other.
In the above formula (IB), R ₂ represents a linear or branched alkyl group having 1 to 20 carbon atoms, m represents 0, 1 or 2, and Ar ₂ has 6 to 10 carbon atoms. Represents an aryl group, Y represents a single bond or an alkylene group having 1 to 10 carbon atoms, R ₃ represents a linear or branched alkylene group having 1 to 5 carbon atoms, and n is an integer of 1 to 100 M ₂ ⁺ represents Na ⁺ , K ⁺ , Li ⁺ or NH ₄ ⁺ . When m is 2, a plurality of R ₂ may be the same or different from each other, and when n is 2 or more, a plurality of R ₃ may be the same or different from each other.

In formula (IA) and formula (IB), preferred examples of R ₁ and R ₂ include CH ₃ , C ₂ H ₅ , C ₃ H ₇ or C ₄ H ₉ . Preferred examples of R _{3 include, -CH 2 -, - CH 2} CH 2 -, - CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) - can be mentioned, -CH ₂ is more preferable examples CH ₂ — may be mentioned. p and m are preferably 0 or 1, and p is particularly preferably 0. Y is preferably a single bond. n is preferably an integer of 1 to 20.

  Specific examples of the anionic surfactant represented by the formula (IA) or the formula (IB) include the following compounds.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose Fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N , N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamines Oxide and the like. Among these nonionic surfactants, polyoxyethylene aryl ethers, polyoxyethylene-polyoxypropylene block copolymers and the like are preferable.

  Specifically, for example, polyoxyethylene naphthyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene stearate Polyoxyethylene alkyl esters such as sorbate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan alkyl esters such as sorbitan trioleate, glycerol monostearate, Nonionic surfactants such as monoglyceride alkyl esters such as glycerol monooleate.

  As the nonionic surfactant, a surfactant represented by the following formula (II-A) or formula (II-B) is preferably used.

In the above formula (II-A), R ¹ represents a hydrogen atom or an alkyl group having 1 to 100 carbon atoms, n and m each represent an integer of 0 to 100, and both n and m are 0. There is no.
In the formula (II-B), ^{R 2} represents a hydrogen atom or an alkyl group of carbon atoms 1 to 100, n and m each represents an integer of 0 to 100, both n and m are 0 There is no.

  Examples of the compound represented by the formula (II-A) include polyoxyethylene phenyl ether, polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and the like. Examples of the compound represented by the formula (II-B) include polyoxyethylene naphthyl ether, polyoxyethylene methyl naphthyl ether, polyoxyethylene octyl naphthyl ether, and polyoxyethylene nonyl naphthyl ether.

  In the compound represented by the above formula (II-A) or formula (II-B), n (the number of repeating units of the oxyethylene chain) is preferably 3 to 50, more preferably 5 to 30. m (the number of repeating units of the oxypropylene chain) is preferably 0 to 10, more preferably 0 to 5. The polyoxyethylene part and the polyoxypropylene part may be present randomly or in blocks.

  Specific examples of the nonionic surfactant represented by the formula (II-A) or the formula (II-B) are shown below. The oxyethylene repeating unit and the oxypropylene repeating unit in the exemplified compound “Y-5” below may be in any form of a random bond or a block bond.

Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, polyoxyalkylamine salts, polyethylene polyamine derivatives, and the like.
Examples of amphoteric surfactants include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, imidazolines, and the like.

  Of the surfactants, anionic surfactants are more preferable. In particular, sulfonate anionic surfactants such as sodium naphthalene sulfonate, sodium alkyl naphthalene sulfonate, sodium benzene sulfonate, sodium toluene sulfonate, sodium polyoxyethylene aryl ether sulfate, sodium polyoxyethylene alkyl ether sulfonate It is preferable to use sodium dialkylsulfosuccinate.

  A phosphoric acid compound can also be used as the low molecular weight hydrophilic compound. Phosphoric acid compounds include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, sodium dihydrogen phosphate, sodium monohydrogen phosphate, primary potassium phosphate, secondary potassium phosphate, tripolyphosphoric acid Sodium, potassium pyrophosphate, sodium hexametaphosphate and the like can be mentioned. Among these, sodium dihydrogen phosphate, sodium monohydrogen phosphate, and sodium hexametaphosphate are preferable.

  A phosphonic acid compound can also be used as the low molecular weight hydrophilic compound. Examples of phosphonic acid compounds include ethylphosphonic acid, propylphosphonic acid, i-propylphosphonic acid, butylphosphonic acid, hexylphosphonic acid, octylphosphonic acid, dodecylphosphonic acid, octadecylphosphonic acid, 2-hydroxyethylphosphonic acid and sodium thereof. Alkyl phosphonic acid monoalkyl esters such as salts or potassium salts, methyl methylphosphonate, methyl ethylphosphonate, methyl 2-hydroxyethylphosphonate and the like, and sodium salts or potassium salts thereof, alkyl such as methylenediphosphonic acid, ethylenediphosphonic acid, etc. Examples include diphosphonic acid and sodium or potassium salts thereof.

  Furthermore, low molecular weight hydrophilic compounds include glycols such as sulfophthalic acid, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and ether or ester derivatives thereof, glycerin, pentaerythritol, tris ( Polyols such as 2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfonic acids such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid and salts thereof, Organic carboxylic acids such as tartaric acid, oxalic acid, citric acid, malic acid, sulfophthalic acid, lactic acid, gluconic acid, amino acids and their salts, betaines (trimethylammonium It can also be used Tate, etc.) and the like.

Only one low molecular weight hydrophilic compound may be used, or two or more low molecular weight hydrophilic compounds may be used in combination as necessary.
The content of the low molecular weight hydrophilic compound is preferably 1 to 100% by mass, more preferably 5 to 70% by mass, and 10 to 50% by mass with respect to the solid content of the constituent layer containing the low molecular hydrophilic compound. Is more preferable.

  The constituent layers of the lithographic printing plate dummy can contain a binder polymer to form a layer. The binder polymer is preferably film-forming. The binder polymer preferably has a property of promoting the removal of the constituent layers by on-press development. That is, the binder polymer is preferably dissolved or dispersed in at least one of dampening water and ink used during printing. The binder polymer to be used can be appropriately selected according to the characteristics of the contained constituent layer. The binder polymer will be described later in detail.

[Fine particles]
The planographic printing plate dummy plate can contain fine particles in at least one of the constituent layers. The fine particles may be either organic fine particles or inorganic fine particles as long as they are present in the lithographic printing plate dummy. Various fine particles known to be contained in a constituent layer of an ordinary lithographic printing plate precursor, such as an undercoat layer, an image recording layer, and a protective layer, may be used. By including fine particles in the constituent layer, when the lithographic printing plate dummy plate is subjected to on-press development, the permeability of dampening water is improved, on-press development is promoted, and edge contamination is prevented. It is done.

<Organic fine particles>
As the organic fine particles, organic resin fine particles, for example, microgel (crosslinked polymer fine particles) and thermoplastic fine particles are preferably used.

(Microgel)
A microgel is a reactive or non-reactive resin particle dispersed in an aqueous medium. The microgel may be in the form of a reactive microgel by having a polymerizable group in the particle surface or on the particle surface, preferably on the particle surface.

  The resin constituting the particles is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, more preferably polyurea or polyurethane, and particularly preferably polyurethane.

  The microgel can be prepared by a known method. For example, a monohydric alcohol having an ethylenically unsaturated group is reacted with an adduct of a polyhydric alcohol and a diisocyanate, and dissolved in ethyl acetate together with a small amount of a surfactant to prepare an oily component. As an aqueous component, an aqueous solution of polyvinyl alcohol is prepared. An oily component and an aqueous component are mixed, and the mixture is emulsified and dispersed by high-speed stirring with a mechanical stirrer, and the solid content concentration is adjusted to obtain a microgel.

(Thermoplastic fine particles)
Examples of the thermoplastic fine particles include Research Disclosure No. 1 of January 1992. 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, European Patent No. 931647, and the like can be preferably exemplified. .

  Specific examples of the polymer constituting the thermoplastic fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and acrylate having a polyalkylene structure. Or homopolymers or copolymers of monomers such as methacrylates or mixtures thereof. Among these, a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate are preferable.

<Inorganic fine particles>
Inorganic fine particles include metals and metal compounds such as oxides, composite oxides, hydroxides, carbonates, sulfates, silicates, phosphates, organic acid salts, nitrides, carbides, sulfides, and the like. The compound of at least 2 or more types of these is mentioned. Specifically, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, zircon oxide, tin oxide, potassium titanate, strontium titanate, aluminum borate, magnesium borate, aluminum hydroxide, magnesium hydroxide, water Calcium oxide, titanium hydroxide, basic magnesium sulfate, calcium carbonate, calcium sulfate, magnesium sulfate, calcium silicate, magnesium silicate, calcium phosphate, silicon nitride, titanium nitride, aluminum nitride, silicon carbide, titanium carbide, zinc sulfide and these The compound of at least 2 or more types of these is mentioned. Preferably, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof can be used.

The shape of the fine particles may be any shape such as a spherical shape, a needle shape, a flat plate shape, a feather shape, a chain shape (beaded shape), or an indefinite shape, but a spherical shape is preferable.
The average particle size of the fine particles is preferably 5 μm or less, more preferably 0.005 to 3 μm, and particularly preferably 0.01 to 2 μm.
A known method can be used to measure the particle diameter. Specific examples include laser diffraction / scattering methods, dynamic light scattering methods, static light scattering methods, dynamic imaging methods, static imaging methods, image analysis methods, and electron microscopy. For example, a fine particle-containing liquid is diluted with distilled water or the like so that the particle concentration is 0.1 to 1% by weight, and a commercially available average particle size measuring device (for example, LA-910 (manufactured by Horiba, Ltd.)) Can be measured easily. Furthermore, the dynamic light scattering method using the laser Doppler effect is preferable because it can measure the particle size up to a small size. In the planographic printing plate dummy plate, for example, a method of observing a section of the planographic printing plate dummy plate with an electron microscope or the like or a method of image analysis is preferable because the particle size can be easily measured.
The particle diameter of the fine particles is a numerical value measured using a laser diffraction / scattering method (measuring device: LA-910, manufactured by Horiba, Ltd.).

  The content of the fine particles is preferably 0.01 to 70% by mass, more preferably 5 to 60% by mass, and still more preferably 10 to 50% by mass with respect to the solid content of the constituent layer containing the fine particles.

[Colorant]
The lithographic printing plate dummy plate can contain a colorant having an absorption maximum at 350 to 800 nm in at least one of the constituent layers. By including a colorant in the constituent layer, it is possible to impart discriminability by a setter color sensor.

The colorant having an absorption maximum at 350 to 800 nm is preferably a water-soluble dye. Examples of water-soluble dyes include anionic dyes and cationic dyes that are excellent in solubility in water.
Examples of water-soluble dyes include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, diphenylmethane dyes, naphthol dyes, triarylmethane dyes, and pyranine dyes. .
The color of the water-soluble dye is not particularly limited, but it is preferable that the color difference is large in order to distinguish between the lithographic printing plate precursor and the lithographic printing plate dummy plate by a setter color sensor. In consideration of the fact that the lithographic printing plate precursor is often colored blue, orange and yellow are preferred, and red is particularly preferred.

As the water-soluble dye, an anionic dye is more preferable. Among the anionic dyes, those having —SO ₃ X (X represents Li, Na or K) or —COOX (X represents Li, Na or K) as the hydrophilic group are preferable.
Examples of the anionic dye include [C. I. Acid Red] 1, 6, 8, 9, 13, 14, 18, 27, 35, 37, 52, 54, 57, 73, 82, 87, 88, 92, 97, 106, 111, 114, 118, 119 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415, [C. I. Acid Orange] 56, [C. I. Acid Yellow] 1, 42, Edible Red No. 2, Edible Red No. 3, Edible Red No. 40, Edible Red No. 104, Edible Red No. 105, Edible Yellow No. 4 (Tartrazine), Edible Yellow No. 5 and the like.
As the azo dye, the disazo dye is more stable to light, heat, and acid than the monoazo dye, and therefore, the color change of the lithographic printing plate dummy plate with time is small, which is more preferable in terms of discriminating ability by the color sensor.

  The content of the colorant is preferably 5 to 30% by mass, more preferably 7 to 25% by mass, and still more preferably 10 to 20% by mass with respect to the total solid content of the constituent layer containing the colorant.

(Matting agent)
The lithographic printing plate dummy plate may contain a matting agent in at least one of the constituent layers. The matting agent is preferably contained in the uppermost layer of the lithographic printing plate dummy. Thereby, the conveyance property (setter conveyance property) by the setter of the planographic printing plate dummy plate can be made excellent. The basic properties desired for particles that act as a matting agent are as follows: the transmission of light used for exposure does not substantially hinder, and it does not soften or become sticky depending on the moisture and temperature in the air. It is preferable to add to the uppermost layer of the lithographic printing plate dummy plate to give appropriate irregularities to the surface and reduce the contact area.
From the viewpoint of suppressing scratching, it is preferable that the matting agent can relieve the stress generated when it is rubbed with the hard aluminum support surface. Further, it is preferable that the matting agent has a high affinity with the uppermost binder, is well kneaded in the film, and is difficult to be detached from the film surface even after the film is formed.

As the matting agent, any known matting agent can be used as long as it satisfies the above basic characteristics. The matting agent fine particles are preferably fine particles having a hydrophilic surface. The fine particles having a hydrophilic surface include organic resin fine particles having a hydrophilic surface or inorganic fine particles having a hydrophilic surface.
The organic resin fine particles having a hydrophilic surface are preferably organic resin fine particles coated with at least one inorganic compound selected from silica, alumina, titania and zirconia. In particular, organic resin fine particles coated with silica are preferable.
The organic resin constituting the organic resin fine particles having a hydrophilic surface is at least one resin selected from a polyacrylic resin, a polyurethane resin, a polystyrene resin, a polyester resin, an epoxy resin, a phenol resin, and a melamine resin. It is preferable that

  Hereinafter, the organic resin fine particles having a hydrophilic surface will be described in detail by taking, as an example, organic resin fine particles coated with silica (hereinafter also referred to as silica-coated organic resin fine particles). It is not limited to this.

(Silica-coated organic resin fine particles)
Silica-coated organic resin fine particles are fine particles obtained by coating fine particles of an organic resin with silica. It is preferable that the organic resin fine particles constituting the core do not soften or become sticky due to moisture in the air or temperature.

  Examples of the organic resin constituting the organic resin fine particles of the silica-coated organic resin fine particles include polyacrylic resins, polyurethane resins, polystyrene resins, polyester resins, epoxy resins, phenol resins, and melamine resins.

Examples of the material for forming the silica layer covering the surface of the silica-coated organic resin fine particles include compounds having an alkoxysilyl group such as a condensate of an alkoxysiloxane compound, in particular, a siloxane material, specifically silica sol, colloidal silica. Preferred are silica fine particles such as silica nanoparticles.
Silica-coated organic resin fine particles are composed of silica particles adhering to the surface of organic resin fine particles as a solid component to form a siloxane compound layer on the surface of organic resin fine particles by condensation reaction of alkoxysiloxane compounds. It may be the configuration.

Silica does not necessarily have to cover the entire surface of the organic resin fine particles. If the surface is coated at an amount of 0.5% by mass or more with respect to the mass of the organic resin fine particles, the effect of the present invention can be easily obtained. . That is, when silica is present on at least a part of the surface of the organic resin fine particles, the affinity with the coexisting water-soluble polymer, for example, PVA is achieved on the surface of the organic fine particles, and external stress is applied. However, dropping of the fine particles is suppressed, and excellent scratch resistance and adhesion resistance can be maintained. Therefore, “silica coating” includes such a state that silica is present on at least a part of the surface of the organic resin fine particles.
The surface coating state of silica can be confirmed by morphological observation with a scanning electron microscope (TEM) or the like. Moreover, the coating amount of silica can be confirmed by detecting Si atoms by elemental analysis such as fluorescent X-ray analysis and calculating the amount of silica present there.

  The method for producing the silica-coated organic resin fine particles is not particularly limited, and the silica surface coating layer is formed simultaneously with the formation of the organic resin fine particles by coexisting the silica fine particles or the silica precursor compound with the monomer component as the raw material of the organic resin fine particles. Alternatively, after forming the organic resin fine particles, the silica fine particles may be physically attached to the surface and then fixed.

  An example of a method for producing silica-coated organic resin fine particles is given below. First, silica and raw material resin (from more water-soluble polymers such as polyvinyl alcohol, methylcellulose, polyacrylic acid, and suspension stabilizers appropriately selected from inorganic suspensions such as calcium phosphate and calcium carbonate) Specifically, a monomer capable of suspension polymerization, a prepolymer capable of suspension cross-linking, or a raw material resin such as a resin liquid) constituting the organic resin is added, stirred, and mixed, and silica and raw material are added. A suspension in which the resin is dispersed is prepared. At that time, a suspension having a target particle size can be formed by adjusting the type of suspension stabilizer, its concentration, the number of stirring revolutions, and the like. Next, the suspension is heated to start the reaction, and resin particles are produced by suspension polymerization or suspension crosslinking of the resin raw material. At this time, the coexisting silica is fixed to the resin particles that are cured by polymerization or cross-linking reaction, particularly near the surface of the resin particles due to the physical properties thereof. Thereafter, the suspension is subjected to solid-liquid separation, and the suspension stabilizer attached to the particles is removed by washing, followed by drying. Thus, substantially spherical silica-coated organic resin fine particles having a desired particle diameter on which silica is immobilized are obtained.

  Thus, it is possible to obtain silica-coated organic resin fine particles having a desired particle diameter by controlling the conditions during suspension polymerization or suspension crosslinking, and without carrying out such control strictly. After producing the resin fine particles, silica-coated organic fine particles having a desired size can be obtained by a mesh filtration method or the like.

  Regarding the addition amount of the raw material in the mixture in producing the silica-coated organic fine particles by the above method, for example, when the total amount of the raw material resin and silica is 100 parts by weight, first, 200 to 800 parts by weight of water as a dispersion medium 0.1 to 20 parts by weight of a suspension stabilizer is added and sufficiently dissolved or dispersed, and a mixture of 100 parts by weight of the raw material resin and silica is added to the liquid, and the dispersed particles have a predetermined particle size. After adjusting the particle size, the liquid temperature is raised to 30 to 90 ° C. and reacted for 1 to 8 hours.

  As for the method for producing silica-coated organic resin fine particles, the above-described method is one example. For example, JP-A-2002-327036, JP-A-2002-173410, JP-A-2004-307837, and Silica-coated organic resin fine particles obtained by the method described in detail in, for example, Kaikai 2006-38246 can also be used suitably.

  Silica-coated organic resin fine particles are also available as commercial products. Specifically, as silica / melamine composite fine particles, Nissan Chemical Industries, Ltd. Optobead 2000M, Optobead 3500M, Optobead 6500M, Optobead 10500M, optobead 3500S, optobead 6500S. As silica / acrylic composite fine particles, Negami Industrial Co., Ltd. Art Pearl G-200 transparent, Art Pearl G-400 transparent, Art Pearl G-800 transparent, Art Pearl GR-400 transparent, Art Pearl GR-600 transparent, Art Pearl GR-800 transparent, Art Pearl J-7P. As silica / urethane composite fine particles, Negami Industrial Co., Ltd. Art Pearl C-400 Transparent, C-800 Transparent, P-800T, U-600T, U-800T, CF-600T, CF800T, Dainichi Seika Co., Ltd. Dynamic Examples include bead CN5070D and dampula coat THU.

  As described above, the organic resin fine particles used in the constituent layer have been described using silica-coated organic resin fine particles as an example. However, for the organic resin fine particles coated with alumina, titania or zirconia, alumina, titania or zirconia is used instead of silica. It can implement similarly.

  As the inorganic fine particles having a hydrophilic surface, known inorganic particles having a hydrophilic surface can be used. In particular, fine particles made of silica, alumina, zirconia or titania are preferable.

Organic resin fine particles can also be used as the matting agent fine particles contained in the constituent layers. As organic resin fine particles, synthesis of poly (meth) acrylates, polystyrene and derivatives thereof, polyamides, polyimides, polyolefins such as low density polyethylene, high density polyethylene, polypropylene, polyurethane, polyurea, polyesters, etc. Preferred are fine particles made of resin and fine particles made of natural polymers such as chitin, chitosan, cellulose, crosslinked starch, and crosslinked cellulose.
Among these, the synthetic resin fine particles have advantages such as easy particle size control and easy control of desired surface characteristics by surface modification.

As for the method for producing organic resin fine particles, a relatively hard resin such as PMMA can be finely divided by a crushing method. However, a method of synthesizing particles by an emulsion / suspension polymerization method is preferable. It is preferably employed because of its ease of control and accuracy.
The production method of organic resin fine particles is “Ultra Fine Particles and Materials”, edited by the Japan Society for Materials Science, published in 裳 華 房 1993, “Preparation and Application of Fine Particles / Powder”, supervised by Haruma Kawaguchi, and published by CMC Publishing 2005. It is described in detail.

  Organic resin fine particles are also available as commercial products. For example, cross-linked acrylic resins MX-300, MX-500, MX-1000, MX-1500H, MR-2HG, MR-7HG, MR-manufactured by Soken Chemical Co., Ltd. 10HG, MR-3GSN, MR-5GSN, MR-7G, MR-10G, MR-5C, MR-7GC, styryl resin-based SX-350H, SX-500H, Sekisui Plastics acrylic resin, MBX-5, MBX-8, MBX-12MBX-15, MBX-20, MB20X-5, MB30X-5, MB30X-8, MB30X-20, SBX-6, SBX-8, SBX-12, SBX-17 Polyolefin resin made by Mitsui Chemicals , Chemipearl W100, W200, W300, W308, W310, W400, W401, W405, W410 W500, WF640, W700, W800, W900, W950, WP100, and the like.

The shape of the matting agent fine particles used in the constituent layer is preferably a true spherical shape, but may be a so-called spindle shape in which a flat plate shape or an elliptical projection is formed.
It is important that the average particle size of the matting agent fine particles is larger than the thickness of the constituent layer containing the matting agent fine particles. The average particle diameter of the matting agent fine particles is preferably 0.3 μm or more larger than the thickness of the constituent layer containing the matting agent fine particles.
The average particle diameter of the matting agent fine particles is preferably 0.3 to 30 μm, more preferably 0.5 to 15 μm, and still more preferably 1 to 10 μm. In this range, a sufficient spacer function can be expressed, it can be easily fixed to the constituent layer, and has an excellent holding function against external contact stress.
The average particle diameter of the matting agent fine particles means a commonly used volume average particle diameter, and the volume average particle diameter can be measured by a laser diffraction / scattering particle size distribution meter. Examples of the measuring device include a particle size distribution measuring device “Microtrack MT-3300II” (manufactured by Nikkiso Co., Ltd.).

The content of the matting agent fine particles in the constituent layer is preferably 5 to 1000 mg / m ² , more preferably 10 to 500 mg / m ² , and still more preferably 20 to 200 mg / m ² .

  The lithographic printing plate dummy plate comprises a chelating agent, a secondary or tertiary amine, a polymerization inhibitor (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2 , 3,5,6-tetrahydroxy-p-quinone, chloranil, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid) and the like.

In the on-press development type lithographic printing plate dummy plate used in the printing method according to the present invention, the constituent layer formed on the aluminum support may be one layer, two layers or three layers. Hereinafter, the constituent layer 1, the constituent layer 2, and the constituent layer 3 are called in order from the side closer to the aluminum support.
Specifically, when only one constituent layer is formed on the aluminum support, the on-press development type lithographic printing plate dummy plate has the constituent layer 1 on the aluminum support.
When the constituent layers formed on the aluminum support are two layers, the on-press development type lithographic printing plate dummy plate has the constituent layers 1 and 2 on the aluminum support, or the constituent layers 1 and It has layer 3 (in this case there is no constituent layer 2).
In the case where the constituent layers formed on the aluminum support are three layers, the on-press development type lithographic printing plate dummy plate has constituent layers 1, 2, and 3 on the aluminum support.

[Constitution layer 1]
The constituent layer 1 preferably contains a binder polymer. As the binder polymer of the constituent layer 1, a polymer having a film-forming property is suitable. Examples of the binder polymer contained in the constituent layer 1 include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, and poly (meth) acrylonitrile.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specific examples include modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.

  As the binder polymer of the constituent layer 1, a water-soluble polymer compound containing a repeating unit having a support adsorptive group and a repeating unit having a hydrophilic group is particularly preferable. As a result, the on-press developability of the lithographic printing plate dummy itself is improved, and edge contamination is suppressed. Edge smear refers to the edge of a lithographic printing plate dummy when it is printed continuously on a roll-like printing paper using a rotary press, such as newspaper printing, so it adheres to the edge. This is a phenomenon in which the used ink is transferred to the printing paper and causes linear stains.

  Below, the water-soluble polymer compound containing the repeating unit which has a support body adsorptive group and the repeating unit which has a hydrophilic group is explained in full detail.

(Support adsorbing group)
Examples of the support adsorptive group include ionic bond formation, hydrogen bond formation, and polar interaction with metals, metal oxides, hydroxy groups, etc. present on the support subjected to anodization treatment or hydrophilization treatment. Examples include groups capable of acting.
Specific examples of the support-adsorptive group are listed below.

In the formula, M ¹ and M ² each independently represent a hydrogen atom, a metal atom contained in an alkali metal or alkaline earth metal, or an ammonium group. From the viewpoint of stain resistance, the support adsorptive group is preferably at least one group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, and salts thereof. The support-adsorbing group is more preferably a phosphonic acid group or a salt thereof (structure 1), a phosphate ester group or a salt thereof (structure 2), a carboxylic acid group or a salt thereof, and a phosphate ester group or a salt thereof. Or it is still more preferable that it is a phosphonic acid group or its salt.
Specifically, the repeating unit having a support-adsorptive group is preferably represented by the following general formula (B1).

In formula (B1), R ^{a to} R ^c each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. Q represents a support-adsorptive group, and a preferred embodiment is the same as described above.
L represents a single bond or a divalent linking group. A divalent linking group can be from 1 to 60 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to 100 hydrogen atoms, and 0 to It consists of up to 20 sulfur atoms, and more specifically, the following structural units or those constituted by a combination thereof can be mentioned.

In the above structure, R ^d and R ^e each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogen atom. n represents an integer of 1 to 4.

  Although the specific example of the repeating unit which has a support body adsorptive group below is shown, this invention is not limited to these.

The polymer compound may have only one type of support adsorptive group or two or more types.
The content of the repeating unit having a support adsorptive group is preferably from 2 to 80 mol%, more preferably from 2 to 70 mol%, still more preferably from 5 to 50 mol%, based on all repeating units of the polymer compound. 10 to 40 mol% is particularly preferable.

(Hydrophilic group)
The polymer compound has a repeating unit having a hydrophilic group in order to increase the hydrophilicity of the surface of the aluminum support and to suppress etch stains.
Specific examples of the hydrophilic group are given below.

In the above formula, M ¹ represents a hydrogen atom, a metal atom contained in an alkali metal or alkaline earth metal, or an ammonium group.
X ⁺ represents a group represented by -N ⁺ R ₁ R _2- , -S ⁺ R _1- , -I ⁺ -, -P ⁺ R ₁ R _2- .
R ₁ and R ₂ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group or an alkynyl group, R ₃ represents an alkylene group, and R ₄ represents an alkyl group, an aryl group, an alkenyl group or an alkynyl group. Represents.
n represents an integer of 1 to 100. L has the same meaning as L described above.

As the hydrophilic group, any functional group having high affinity with water can be suitably used. However, a sulfonic acid (salt) group, an amide group, a polyalkylene oxide group, a hydroxyl group, and a monosulfuric acid group can be used. Ester (salt) group, sulfonamide group, amino group, sulfuric monoamide (salt) group, betaine structure is preferable, sulfonic acid (salt) group, amide group, polyalkylene oxide group, hydroxyl group, sulfuric monoester (salt) group , Sulfonamido group, amino group, sulfuric monoamide (salt) group and betaine structure are more preferred, and sulfonic acid (salt) group, amide group, polyalkylene oxide group, hydroxyl group and betaine structure are particularly preferred.
The hydrophilic group is particularly preferably at least one group or structure selected from a sulfonic acid group and a salt thereof, an amide group, and a betaine structure.

  Specifically, the repeating unit having a hydrophilic group is preferably represented by the following general formula (B2).

In formula (B2), R ^{a to} R ^c each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. L has the same meaning as L described above. W represents a hydrophilic group, and a preferred embodiment is the same as described above.

  Specific examples of the repeating unit having a hydrophilic group are shown below, but the present invention is not limited thereto.

The polymer compound may have only one kind of hydrophilic group or two or more kinds.
The content of the repeating unit having a hydrophilic group is preferably from 30 to 98 mol%, more preferably from 40 to 90 mol%, still more preferably from 50 to 90 mol%, based on all repeating units of the polymer compound.

(Other repeat units)
In addition to the repeating unit having a support-adsorptive group and the repeating unit having a hydrophilic group, the polymer compound has another repeating unit (hereinafter sometimes simply referred to as “other repeating unit”). A copolymer may also be used. Examples of other repeating units include repeating units derived from various known monomers.

The polymer compound includes, for example, a repeating unit having a support-adsorbing group, a repeating unit having a hydrophilic group, a repeating unit corresponding to an alkyl (meth) acrylate or an aralkyl ester, (meth) acrylamide or the like. It may have a repeating unit corresponding to the derivative, a repeating unit corresponding to α-hydroxymethyl acrylate, and a repeating unit corresponding to the styrene derivative.
The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms and an alkyl group having the aforementioned substituent having 2 to 8 carbon atoms, and a methyl group is more preferable. Examples of the (meth) acrylic acid aralkyl ester include benzyl (meth) acrylate.
Examples of (meth) acrylamide derivatives include N-isopropylacrylamide, N-phenylmethacrylamide, N- (4-methoxycarbonylphenyl) methacrylamide, N, N-dimethylacrylamide, morpholinoacrylamide and the like.
Examples of the α-hydroxymethyl acrylate include ethyl α-hydroxymethyl acrylate and cyclohexyl α-hydroxymethyl acrylate.
Examples of styrene derivatives include styrene and 4-tertbutylstyrene.

  The content of other repeating units is preferably 40 mol% or less, more preferably 30 mol%, still more preferably 20 mol% or less, based on all repeating units of the polymer compound.

  The polymer compound includes a repeating unit having at least one group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group and a salt thereof as the support adsorptive group, a sulfonic acid group as the hydrophilic group, and Particularly preferred is a copolymer comprising a salt, an amide group and a repeating unit having at least one group or structure selected from betaine structures.

The binder polymer contained in the constituent layer 1 may be used alone or in combination of two or more.
As for content of the binder polymer in the structure layer 1, 20-100 mass% is preferable with respect to the total solid of the structure layer 1, 30-95 mass% is more preferable, 40-90 mass% is still more preferable.

[Constitution layer 2]
The constituent layer 2 is a layer that can be removed by at least one of dampening water and printing ink. The constituent layer 2 contains a resin. The resin is mainly used for the purpose of improving the film strength of the constituent layer 2. The resin contained in the constituent layer 2 is preferably a resin having a film-forming property, and a known resin used as a binder polymer in the image recording layer of the on-press development type lithographic printing plate precursor can be used. Of these, acrylic resins, polyvinyl acetal resins, polyurethane resins and the like are preferable.

  The resin contained in the constituent layer 2 preferably has a hydrophilic group. The hydrophilic group contributes to imparting on-press developability to the constituent layer 2.

  Examples of the hydrophilic group include a hydroxy group, a carboxy group, an alkylene oxide structure, an amino group, an ammonium group, an amide group, a sulfo group, and a phosphoric acid group. Among them, an alkylene oxide unit having 2 or 3 carbon atoms An alkylene oxide structure having 1 to 9 is preferable. The hydrophilic group can be imparted to the resin by, for example, copolymerizing a monomer having a hydrophilic group.

  Preferable examples of the resin contained in the constituent layer 2 include a polymer compound having a polyoxyalkylene chain in the side chain. By allowing the constituent layer 2 to contain a polymer compound having a polyoxyalkylene chain in the side chain (hereinafter also referred to as a specific polymer compound), the permeability of the fountain solution is promoted and the on-press developability is improved.

  The resin constituting the main chain of the specific polymer compound includes acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, methacrylic resin, polystyrene resin, novolac type phenol resin, polyester Examples thereof include resins, synthetic rubbers, and natural rubbers, and acrylic resins are particularly preferable.

  The specific polymer compound is substantially free of a perfluoroalkyl group. The “perfluoroalkyl group” means a group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms. “Substantially free of perfluoroalkyl groups” means that the mass ratio of fluorine atoms present as perfluoroalkyl groups in the polymer compound is less than 0.5% by mass. It is preferable not to contain a perfluoroalkyl group. The mass ratio of fluorine atoms is measured by elemental analysis.

The alkylene oxide (oxyalkylene) in the polyoxyalkylene chain is preferably an alkylene oxide having 2 to 6 carbon atoms, more preferably ethylene oxide (oxyethylene) or propylene oxide (oxypropylene), and still more preferably ethylene oxide.
2-50 are preferable and, as for the repeating number of the alkylene oxide in a polyoxyalkylene chain, ie, a poly (alkylene oxide) site | part, 4-25 are more preferable.
If the number of alkylene oxide repeats is 2 or more, the permeability of the fountain solution is sufficiently improved, and if the number of repeats is 50 or less, the printing durability due to wear does not deteriorate, which is preferable.

  The poly (alkylene oxide) moiety is preferably contained as a side chain of the polymer compound in a structure represented by the following general formula (1). More preferably, it is contained as a side chain of the acrylic resin in a structure represented by the following general formula (1).

In general formula (1), y is preferably 2 to 50, and more preferably 4 to 25. R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom or an organic group. As an organic group, a C1-C6 alkyl group is preferable, and a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, t-butyl group, n- Examples include pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, cyclopentyl group, and cyclohexyl group.
In the general formula (1), R ₁ is preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom. R ₂ is particularly preferably a hydrogen atom or a methyl group.

  The specific polymer compound may further contain a copolymer component for the purpose of improving various performances such as film strength as long as the original effects of the specific polymer compound are not impaired. As a preferable copolymer component, what is represented by the following general formula (2) can be mentioned.

In the general formula (2), R ²¹ represents a hydrogen atom or a methyl group. R ²² represents a substituent. Preferable examples of R ²² include an ester group, an amide group, a cyano group, a hydroxy group, or an aryl group. Especially, the phenyl group which may have an ester group, an amide group, or a substituent is preferable. Examples of the substituent for the phenyl group include an alkyl group, an aralkyl group, an alkoxy group, and an acetoxymethyl group.

  Examples of the copolymer component represented by the general formula (2) include acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, N-substituted acrylamides, N-substituted methacrylamides, N, N -2 substituted acrylamides, N, N-2 substituted methacrylamides, styrenes, acrylonitriles, methacrylonitriles and the like. Preferably, acrylic esters, methacrylic esters, acrylamides, methacrylamides, N-substituted acrylamides, N-substituted methacrylamides, N, N-2 substituted acrylamides, N, N-2 substituted methacrylamides And styrenes.

  The specific polymer compound may have a crosslinkable functional group. Examples of the crosslinkable functional group include ethylenically unsaturated groups such as (meth) acrylic groups, vinyl groups, allyl groups, and styryl groups, and epoxy groups. The crosslinkable functional group can be introduced into the specific polymer compound by polymer reaction or copolymerization. For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

  The ratio of the repeating unit having a poly (alkylene oxide) site to all repeating units constituting the specific polymer compound is preferably 0.5 to 80 mol%, more preferably 0.5 to 50 mol%.

  Specific examples of the specific polymer compound are shown below, but the present invention is not limited thereto. In the following specific examples, the ratio of repeating units is a molar ratio. Me represents a methyl group.

  As the specific polymer compound, a hydrophilic polymer compound such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used in combination as required. Further, a lipophilic polymer compound and a hydrophilic polymer compound can be used in combination.

  The specific polymer compound may be present in the form of fine particles in the constituent layer 2 in addition to the form existing as a binder of the constituent layer 2 component. When present in the form of fine particles, the average particle size of the fine particles is suitably 10 to 1000 nm, preferably 20 to 300 nm, particularly preferably 30 to 120 nm.

  As another preferred example of the resin contained in the component layer 2, a polymer compound having a polymer chain bonded to the nucleus by a sulfide bond with a polyfunctional thiol having 6 to 10 functional groups as a nucleus (hereinafter referred to as a star shape) Also referred to as a polymer compound). As the star-shaped polymer compound, a compound described in JP 2012-148555 A can be preferably used because the permeability of the fountain solution is promoted and the on-press developability is improved.

  The resin contained in the constituent layer 2 preferably has a mass average molecular weight (Mw) of 2000 or more, more preferably 5000 or more, and still more preferably 10,000 to 300,000.

As the resin contained in the constituent layer 2, one type may be used alone, or two or more types may be mixed and used.
The content of the resin in the constituent layer 2 is suitably 3 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the constituent layer 2.

The constituent layer 2 can contain a plasticizer in order to impart flexibility and the like of the coating film. Examples of the plasticizer include phthalic acid diesters such as dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, and butyl benzyl phthalate. , Aliphatic dibasic esters such as dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, epoxidized triglycerides such as epoxidized soybean oil, tricres Examples thereof include phosphoric acid esters such as zilphosphate, trioctyl phosphate and trischlorethyl phosphate, and benzoic acid esters such as benzyl benzoate.
In addition, conventionally known monomers and prepolymers (dimers, trimers, oligomers, etc.) used as polymerizable compounds in the image recording layer of a lithographic printing plate precursor are also used as plasticizers. The constituent layer 2 can further contain known additives used for the image recording layer of the on-press development type lithographic printing plate precursor.

  Two or more plasticizers may be used in combination. The content of the plasticizer is preferably 0.1 to 50% by mass, and more preferably 1 to 30% by mass with respect to the total solid content of the constituent layer 2.

[Structure layer 3]
The constituent layer 3 is a layer that can be removed by dampening water and / or printing ink on the printing press. The constituent layer 3 has a function of protecting the surface of the planographic printing plate dummy plate.
The constituent layer 3 contains a polymer having film-forming properties. Examples of the polymer contained in the constituent layer 3 include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, and poly (meth) acrylonitrile.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specific examples include modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.

One type of polymer contained in the constituent layer 3 may be used alone, or two or more types may be mixed and used.
20-100 mass% is preferable with respect to the total solid of the structural layer 3, and, as for content of the polymer in the structural layer 3, 30-95 mass% is more preferable, and 40-90 mass% is still more preferable.

The constituent layer 3 can also contain a polysaccharide. Examples of polysaccharides include starch derivatives (eg, dextrin, enzymatically degraded dextrin, hydroxypropylated starch, carboxymethylated starch, phosphate esterified starch, polyoxyalkylene grafted starch, cyclodextrin), celluloses (eg, carboxymethylcellulose, carboxy Ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, methylpropyl cellulose, etc.), carrageenan, alginic acid, guar gum, locust bean gum, xanthan gum, gum arabic, soybean polysaccharide and the like.
Among them, dextrin, starch derivatives such as polyoxyalkylene grafted starch, gum arabic, carboxymethyl cellulose, soybean polysaccharide and the like are preferably used.
The content of the polysaccharide is preferably 1 to 20% by mass with respect to the total solid content of the constituent layer 3.
Constituent layer 3 further protects on-press development type lithographic printing plate precursors such as a plasticizer for imparting flexibility, a surfactant for improving coatability, and inorganic fine particles for controlling surface slipperiness. It can contain known additives used in the layer.

  Each constituent layer can be formed by preparing a coating solution by dissolving or dispersing each constituent layer component in water or a mixed solvent of water and an organic solvent, and applying and drying the coating solution. The coating can be performed by a known method. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating and the like are used.

When the on-press development type lithographic printing plate dummy plate according to the present invention has an aluminum support and one constituent layer formed thereon, that is, when the constituent layer 1 is provided, the constituent layer 1 has the above low molecular weight. Contains a hydrophilic compound and the binder polymer. As the binder polymer, a water-soluble polymer compound containing a repeating unit having the above-mentioned support-adsorbing group and a repeating unit having a hydrophilic group is preferable. Preferred components contained in the constituent layer 1 include the fine particles and the colorant.
The thickness of the constituent layers 1 is preferably 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred.

When the on-press development type lithographic printing plate dummy plate according to the present invention has an aluminum support and two constituent layers formed thereon, that is, the constituent layers 1 and 2, the constituent layers 1 contains the binder polymer. As the binder polymer, a water-soluble polymer compound containing a repeating unit having the above-mentioned support-adsorbing group and a repeating unit having a hydrophilic group is preferable. Preferable components contained in the constituent layer 1 include the fine particles, the colorant, and the low molecular weight hydrophilic compound.
The constituent layer 2 contains the resin. Preferable components contained in the constituent layer 2 include the low molecular weight hydrophilic compound, the colorant, and the fine particles.
The thickness of the constituent layers 1 is preferably 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred. The thickness of the constituent layers 2 is preferably from 0.01 to 3 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred.

When the on-press development type lithographic printing plate dummy plate according to the present invention has an aluminum support and two constituent layers formed thereon, that is, the constituent layer 1 and the constituent layer 3, 1 contains the binder polymer. As the binder polymer, a water-soluble polymer compound containing a repeating unit having the above-mentioned support-adsorbing group and a repeating unit having a hydrophilic group is preferable. Preferable components contained in the constituent layer 1 include the fine particles, the colorant, and the low molecular weight hydrophilic compound.
The constituent layer 3 contains the polymer. Preferred components contained in the constituent layer 3 include the low molecular weight hydrophilic compound, the colorant, the fine particles, and the matting agent.
The thickness of the constituent layers 1 is preferably 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred. The thickness of the constituent layers 3 is preferably from 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred.

When the on-press development type lithographic printing plate dummy plate according to the present invention has an aluminum support and three constituent layers formed thereon, that is, it has constituent layers 1, constituent layers 2 and constituent layers 3. In the case, the constituent layer 1 contains the binder polymer. As the binder polymer, a water-soluble polymer compound containing a repeating unit having the above-mentioned support-adsorbing group and a repeating unit having a hydrophilic group is preferable. Preferable components contained in the constituent layer 1 include the fine particles, the colorant, and the low molecular weight hydrophilic compound.
The constituent layer 2 contains the resin. Preferable components contained in the constituent layer 2 include the low molecular weight hydrophilic compound, the colorant, and the fine particles.
The constituent layer 3 contains the polymer. Preferred components contained in the constituent layer 3 include the low molecular weight hydrophilic compound, the colorant, the fine particles, and the matting agent.
The thickness of the constituent layers 1 is preferably 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred. The thickness of the constituent layers 2 is preferably from 0.01 to 3 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred. The thickness of the constituent layers 3 is preferably from 0.01 to 5 [mu] m / ^{m 2,} more preferably ^{0.05~2μm / m 2, 0.1~1μm / m} 2 is particularly preferred.

  In the on-press development type lithographic printing plate dummy plate according to the present invention, it is desirable that the number of constituent layers is small from the viewpoint of on-press developability. On the other hand, if it is intended to add other functions, such as a function that contains a matting agent and eliminates the need for interleaving paper at the time of lamination, and a function that improves scratch resistance of the planographic printing plate dummy plate surface, A configuration or a three-layer configuration is desirable.

[On-press development type lithographic printing plate precursor]
The on-press development type lithographic printing plate precursor used in the printing method according to the present invention has an image recording layer containing a polymerization initiator containing an organic boron-containing anion on an aluminum support.

[Support]
The aluminum support of the on-press development type lithographic printing plate precursor is the same as the description of the aluminum support in the on-press development type lithographic printing plate dummy plate.

(Image recording layer)
The image recording layer contains a polymerization initiator containing an organic boron-containing anion. In addition to the polymerization initiator containing an organic boron-containing anion, the image recording layer may contain a known polymerization initiator used for the image recording layer of the on-press development type lithographic printing plate precursor.
(Polymerization initiator containing an organic boron-containing anion)

In the polymerization initiator containing an organic boron-containing anion, the organic boron-containing anion is preferably a tetraarylborate anion.
The tetraarylborate anion is represented by the following general formula (I).

In the general formula _{(I), R 1, R} 2, R 3 and _{R 4} each independently represents a heteroaryl group the aryl group or 5 to 20 carbon atoms having from 6 to 20 carbon atoms. The aryl group and heteroaryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, and an aryl group.
Specific examples of the aryl group include phenyl group, tolyl group, xylyl group, mesityl group, duryl group, methoxyphenyl group, dimethoxyphenyl group, chlorophenyl group, fluorophenyl group, trifluoromethylphenyl group, pentafluorophenyl group, naphthyl group. Etc. Specific examples of the heteroaryl group include pyridyl group, pyrimidyl group, furanyl group, pyrrolyl group, imidazolyl group, triazolyl group, tetrazolyl group, indolyl group, quinolinyl group, oxadiazolyl group, and benzoxazolyl group.
In the general formula (I), R ₁ , R ₂ , R ₃ and R ₄ are preferably a substituted or unsubstituted phenyl group. More preferably, at least three of R ₁ , R ₂ , R ₃ and R ₄ are the same substituted or unsubstituted phenyl group.

  In the polymerization initiator containing an organic boron-containing anion, the cation forming the counter ion of the organic boron-containing anion is preferably an iodonium cation, and particularly preferably a diaryl iodonium cation. As the diaryliodonium cation, a compound represented by the structure (I) of US Pat. No. 7,524,614 is preferable.

Among the polymerization initiators containing an organic boron-containing anion, an iodonium compound containing an organic boron-containing anion and a diaryl iodonium cation is preferable.
Specific examples of iodonium compounds containing an organic boron-containing anion and a diaryliodonium cation include 4-octyloxyphenylphenyliodonium tetraphenylborate, [4-[(2-hydroxytetradecyl) oxy] phenyl] phenyliodonium tetraphenylborate, Bis (4-tert-butylphenyl) iodonium tetraphenylborate, 4-methylphenyl-4′-hexylphenyliodonium tetraphenylborate, 4-methylphenyl-4′-cyclohexylphenyliodonium tetraphenylborate, bis (tert-butylphenyl) ) Iodonium tetrakis (pentafluorophenyl) borate, 4-hexylphenylphenyliodonium tetraphenylborate, 4-cyclohexyl Silphenylphenyliodonium tetraphenylborate, 2-methyl-4-tert-butylphenyl-4′-methylphenyliodonium tetraphenylborate, 4-methylphenyl-4′-dodecylphenyliodoniumtetrakis (4-fluorophenyl) borate, bis Examples thereof include (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate and bis (4-tert-butylphenyl) iodoniumtetrakis (1-imidazolyl) borate, but are not limited thereto. Among these, bis (4-tert-butylphenyl) iodonium tetraphenylborate, 4-methylphenyl-4′-hexylphenyliodonium tetraphenylborate, 2-methyl-4-tert-butylphenyl-4′-methylphenyl Iodonium tetraphenylborate and 4-methylphenyl-4′-cyclohexylphenyliodonium tetraphenylborate are preferred.

One kind of polymerization initiator containing an organic boron-containing anion may be used alone, or two or more kinds may be mixed and used.
The content of the polymerization initiator containing an organic boron-containing anion is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and more preferably 0.8 to 20% with respect to the total solid content of the image recording layer. Mass% is particularly preferred.

The image recording layer can contain components contained in the image recording layer of a normal on-press development type lithographic printing plate precursor in addition to the polymerization initiator containing the organic boron-containing anion.
According to one aspect, the image recording layer is an image recording layer (hereinafter, also referred to as image recording layer A) containing an infrared absorber, a polymerizable compound, and a binder polymer in addition to the polymerization initiator.
According to another aspect, the image recording layer is an image recording layer (hereinafter also referred to as image recording layer B) containing an infrared absorber, a polymerizable compound, and a polymer compound in the form of fine particles in addition to the polymerization initiator. ).

(Image recording layer A)
The image recording layer A contains an infrared absorber, the polymerization initiator, a polymerizable compound, and a binder polymer. Hereinafter, the components of the image recording layer A will be described.

<Infrared absorber>
The infrared absorber has a function of converting absorbed infrared rays into heat and a function of being excited by infrared rays to transfer electrons and / or energy to a polymerization initiator. The infrared absorber used is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm, more preferably a dye.

  As the dye, those described in Paragraph Nos. [0082] to [0088] of JP 2014-104631 A can be used.

  The particle diameter of the pigment is preferably 0.01 to 1 μm, and more preferably 0.01 to 0.5 μm. In order to disperse the pigment, a known dispersion technique used for ink production or toner production can be used. Details are described in “Latest Pigment Applied Technology” (CMC Publishing, 1986).

An infrared absorber may use only 1 type and may use 2 or more types together.
The content of the infrared absorber is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and particularly preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the image recording layer. Part by mass.

<Polymerizable compound>
The polymerizable compound is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. Specifically, the polymerizable compounds described in paragraph numbers [0109] to [0113] of JP 2014-104631 A can be used.

  Among them, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, etc. are excellent in the balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide modified acrylates are particularly preferred.

  Details of the method of use such as the structure of the polymerizable compound, whether it is used alone or in combination, and the amount added can be arbitrarily set according to the performance design of the final on-press development type lithographic printing plate precursor. The content of the polymerizable compound is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, and particularly preferably 15 to 60% by mass with respect to the total solid content of the image recording layer.

<Binder polymer>
The binder polymer is mainly used for the purpose of improving the film strength of the image recording layer. A conventionally well-known thing can be used for a binder polymer, The polymer which has film property is preferable. Of these, acrylic resins, polyvinyl acetal resins, polyurethane resins and the like are preferable.

  As a suitable binder polymer, as described in JP-A-2008-195018, the main chain or the side chain, preferably the side chain, has a crosslinkable functional group for improving the film strength of the image area. Things. Crosslinking is formed between the polymer molecules by the crosslinkable group, and curing is accelerated.

  The crosslinkable functional group is preferably an ethylenically unsaturated group such as a (meth) acryl group, vinyl group, allyl group, or styryl group, or an epoxy group. The crosslinkable functional group is introduced into the polymer by polymer reaction or copolymerization. can do. For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

  The content of the crosslinkable group in the binder polymer is preferably 0.1 to 10.0 mmol, more preferably 0.25 to 7.0 mmol, and particularly preferably 0.5 to 5.5 mmol per 1 g of the binder polymer. .

  The binder polymer preferably has a hydrophilic group. The hydrophilic group contributes to imparting on-press developability to the image recording layer. In particular, the coexistence of the crosslinkable group and the hydrophilic group makes it possible to achieve both printing durability and on-press developability.

  Examples of the hydrophilic group include a hydroxy group, a carboxy group, an alkylene oxide structure, an amino group, an ammonium group, an amide group, a sulfo group, and a phosphoric acid group. Among them, an alkylene oxide unit having 2 or 3 carbon atoms. An alkylene oxide structure having 1 to 9 is preferable. The hydrophilic group can be imparted to the binder polymer by, for example, copolymerizing a monomer having a hydrophilic group.

  In the binder polymer, an oleophilic group such as an alkyl group, an aryl group, an aralkyl group, and an alkenyl group can be introduced in order to control the inking property. For example, it can be performed by copolymerizing a lipophilic group-containing monomer such as an alkyl methacrylate ester.

  The binder polymer preferably has a mass average molecular weight (Mw) of 2,000 or more, more preferably 5,000 or more, and still more preferably 10,000 to 300,000.

  The content of the binder polymer is suitably from 3 to 90 mass%, preferably from 5 to 80 mass%, more preferably from 10 to 70 mass%, based on the total solid content of the image recording layer.

  Preferable examples of the binder polymer include a polymer compound having a polyoxyalkylene chain in the side chain. By containing a polymer compound having a polyoxyalkylene chain in the side chain (hereinafter also referred to as POA chain-containing polymer compound) in the image recording layer, the permeability of the fountain solution is promoted and the on-press developability is improved. To do.

  The resin constituting the main chain of the POA chain-containing polymer compound includes acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, methacrylic resin, polystyrene resin, and novolac phenolic resin. , Polyester resin, synthetic rubber and natural rubber, and acrylic resin is particularly preferable.

The POA chain-containing polymer compound is substantially free of perfluoroalkyl groups. “Substantially free of perfluoroalkyl group” means that the mass ratio of fluorine atoms present as a perfluoroalkyl group in the polymer compound is less than 0.5% by mass, and preferably does not contain. The mass ratio of fluorine atoms is measured by elemental analysis.
The “perfluoroalkyl group” is a group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms.

The alkylene oxide (oxyalkylene) in the polyoxyalkylene chain is preferably an alkylene oxide having 2 to 6 carbon atoms, more preferably ethylene oxide (oxyethylene) or propylene oxide (oxypropylene), and still more preferably ethylene oxide.
2-50 are preferable and, as for the repeating number of the alkylene oxide in a polyoxyalkylene chain, ie, a poly (alkylene oxide) site | part, 4-25 are more preferable.
If the number of alkylene oxide repeats is 2 or more, the permeability of the fountain solution is sufficiently improved, and if the number of repeats is 50 or less, the printing durability due to wear does not deteriorate, which is preferable.
Regarding the poly (alkylene oxide) moiety, the structure described in paragraph Nos. [0060] to [0062] of JP-A-2014-104631 is preferable.

  The POA chain-containing polymer compound may have crosslinkability in order to improve the film strength of the image area. The POA chain-containing polymer compound having crosslinkability is described in paragraph numbers [0063] to [0072] of JP 2014-104631 A.

  The ratio of the repeating unit having a poly (alkylene oxide) moiety to the total repeating units constituting the POA chain-containing polymer compound is not particularly limited, but is preferably 0.5 to 80 mol%, more preferably 0.5 to 50 mol%. Specific examples of the POA chain-containing polymer compound include those described in paragraphs [0075] to [0076] of JP-A-2014-104631.

  If necessary, the POA chain-containing polymer compound can be used in combination with a hydrophilic polymer compound such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018. Further, a lipophilic polymer compound and a hydrophilic polymer compound can be used in combination.

  The form of the POA chain-containing polymer compound in the image recording layer may exist in the form of fine particles, in addition to being present as a binder that functions as a linking agent for the image recording layer components. When present in the form of fine particles, the average particle size is suitably from 10 to 1000 nm, preferably from 20 to 300 nm, particularly preferably from 30 to 120 nm.

  The content of the POA chain-containing polymer compound is preferably from 3 to 90 mass%, more preferably from 5 to 80 mass%, based on the total solid content of the image recording layer. Within the range of 3 to 90% by mass, the permeability of the dampening water and the image formability can be more reliably achieved.

  As another preferred example of the binder polymer, a polymer compound having a polyfunctional thiol having 6 or more and 10 or less functions as a nucleus, a polymer chain bonded to the nucleus by a sulfide bond, and the polymer chain having a polymerizable group (Hereinafter also referred to as a star polymer compound). As the star polymer compound, for example, compounds described in JP2012-148555A can be preferably used.

The star-shaped polymer compound has a polymerizable group such as an ethylenically unsaturated bond for improving the film strength of the image portion as described in JP-A-2008-195018, as a main chain or a side chain, preferably a side chain. What has in a chain | strand is mentioned. Crosslinking is formed between the polymer molecules by the polymerizable group, and curing is accelerated.
As the polymerizable group, an ethylenically unsaturated group such as a (meth) acryl group, a vinyl group, an allyl group, or a styryl group, or an epoxy group is preferable, and a (meth) acryl group, a vinyl group, or a styryl group is polymerizable. It is more preferable from the viewpoint, and a (meth) acryl group is particularly preferable. These groups can be introduced into the polymer by polymer reaction or copolymerization. For example, a reaction between a polymer having a carboxy group in the side chain and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used. A polymerizable group may be used in combination.

  The content of the polymerizable group in the star polymer compound is preferably 0.1 to 10.0 mmol, more preferably 0.25 to 7.0 mmol, particularly preferably 0.5, per 1 g of the star polymer compound. ~ 5.5 mmol.

  The star polymer compound preferably further has a hydrophilic group. The hydrophilic group contributes to imparting on-press developability to the image recording layer. In particular, the coexistence of a polymerizable group and a hydrophilic group makes it possible to achieve both printing durability and developability.

As the hydrophilic group, —SO ₃ M ¹ , —OH, —CONR ¹ R ² (M ¹ represents hydrogen, metal ion, ammonium ion, phosphonium ion, R ¹ and R ² each independently represents a hydrogen atom, , alkyl group, alkenyl group, .R ¹ and ^{R 2} representing an aryl group may be bonded to form a ^{ring), -. N + R 3} R 4 R 5 X - (R 3 ~R 5 are each independently and an alkyl group having 1 to 8 carbon atoms and, X ^- represents a counter anion), a group represented by the groups and the general formula represented by the following general formula (1) (2).

  In the above formula, n and m each independently represent an integer of 1 to 100, and R each independently represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.

  When the star polymer compound is a star polymer compound having a polyoxyalkylene chain (for example, a group represented by the above general formula (1) or (2)) on the side difference, The star polymer compound is also a polymer compound having the polyoxyalkylene chain in the side chain.

Among the hydrophilic groups, —CONR ¹ R ² , a group represented by General Formula (1) and a group represented by General Formula (2) are preferable, and represented by —CONR ¹ R ² and General Formula (1) The group represented by the general formula (1) is particularly preferable. Further, among the groups represented by the general formula (1), n is more preferably 1 to 10, and particularly preferably 1 to 4. R is more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. Two or more hydrophilic groups may be used in combination.

  The star polymer compound preferably has substantially no carboxylic acid group, phosphoric acid group or phosphonic acid group. Specifically, it is preferably less than 0.1 mmol / g, more preferably less than 0.05 mmol / g, and particularly preferably 0.03 mmol / g or less. When these acid groups are less than 0.1 mmol / g, developability is further improved.

  In addition, a lipophilic group such as an alkyl group, an aryl group, an aralkyl group, or an alkenyl group may be introduced into the star polymer compound in order to control the inking property. Specifically, a lipophilic group-containing monomer such as alkyl methacrylate ester may be copolymerized.

  Specific examples of the star polymer compound include those described in paragraphs [0153] to [0157] of JP-A-2014-104631.

  The star polymer compound can be synthesized by a known method such as radical polymerization of a monomer constituting the polymer chain in the presence of a polyfunctional thiol compound.

  The mass average molecular weight of the star polymer compound is preferably 5,000 to 500,000, more preferably 10,000 to 250,000, and particularly preferably 20,000 to 150,000. In this range, the on-press developability and printing durability become better.

One type of star polymer compound may be used alone, or two or more types may be mixed and used. Moreover, you may use together with a normal linear binder polymer.
The content of the star polymer compound is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, and particularly preferably 15 to 85% by mass with respect to the total solid content of the image recording layer.
In particular, the star polymer compound described in JP-A-2012-148555 is preferred because the permeability of the fountain solution is promoted and the on-press developability is improved.

<Other ingredients>
The image recording layer A can contain other components described below as required.

(1) Low molecular weight hydrophilic compound The image recording layer may contain a low molecular weight hydrophilic compound in order to improve the on-press developability without reducing the printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and salts thereof, phenylphosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

  Among these, it is preferable to contain at least one selected from polyols, organic sulfates, organic sulfonates, and betaines.

  Specific examples of the organic sulfonates are described in paragraphs [0026] to [0031] of JP-A-2007-276454 and paragraphs [0020] to [0047] of JP-A-2009-154525. Compound etc. are mentioned. The salt may be a potassium salt or a lithium salt.

  Examples of the organic sulfate include compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

  As the betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable. Specific examples include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethyl. Ammonioobylate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, Examples include 3- (1-pyridinio) -1-propanesulfonate.

  Since low molecular weight hydrophilic compounds have a small hydrophobic part structure, the dampening solution penetrates into the exposed part of the image recording layer (image part) and does not reduce the hydrophobicity or film strength of the image part. The ink acceptability and printing durability of the layer can be maintained well.

A low molecular weight hydrophilic compound may be used independently and may be used in mixture of 2 or more types.
The addition amount of the low molecular weight hydrophilic compound is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass with respect to the total solid content of the image recording layer. In this range, good on-press developability and printing durability can be obtained.

(2) Grease Sensitizer A grease sensitizer such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer can be used in the image recording layer in order to improve the inking property. In particular, when an inorganic stratiform compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic stratiform compound, and have an effect of preventing a decrease in the inking property during printing by the inorganic stratiform compound.

  The phosphonium compound, the nitrogen-containing low molecular weight compound, and the ammonium group-containing polymer are specifically described in paragraph numbers [0184] to [0190] of JP-A-2014-104631.

  The content of the sensitizer is preferably 0.01 to 30.0% by mass, more preferably 0.1 to 15.0% by mass, and more preferably 1 to 10% by mass with respect to the total solid content of the image recording layer. Is more preferable.

(3) Others The image recording layer includes, as other components, a surfactant, a colorant, a bake-out agent, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, inorganic fine particles, an inorganic layered compound, a co-sensitizer, A chain transfer agent and the like can be contained. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. The compound and addition amount described in paragraph [0060] of FIG.

<Formation of image recording layer A>
For the image recording layer A, for example, as described in paragraphs [0142] to [0143] of JP-A-2008-195018, the necessary components described above are dispersed or dissolved in a known solvent to prepare a coating solution. Then, this coating solution is formed on the support directly or through an undercoat layer by a known method such as bar coater coating and then dried. The image recording layer coating amount (solid content) on the support obtained after coating and drying is usually 0.3 to 3.0 g / m ² , although it varies depending on the application. Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

(Image recording layer B)
The image recording layer B contains an infrared absorber, the polymerization initiator, a polymerizable compound, and a polymer compound in the form of fine particles. Hereinafter, the components of the image recording layer B will be described.

  Regarding the infrared absorbent and the polymerizable compound in the image recording layer B, the infrared absorbent and the polymerizable compound described in the image recording layer A can be similarly used.

<High molecular compound in the form of fine particles>
Polymer compounds in the form of fine particles (polymer fine particles) include thermoplastic polymer fine particles, thermoreactive polymer fine particles, polymer fine particles having a polymerizable group, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). It is preferable to be selected. Among these, polymer fine particles and microgels having a polymerizable group are preferable. In a particularly preferred embodiment, the particulate polymeric compound comprises at least one ethylenically unsaturated polymerizable group. Due to the presence of such a polymer compound in the form of fine particles, the effect of improving the printing durability of the exposed portion and the on-press developability of the unexposed portion can be obtained.

As thermoplastic polymer fine particles, Research Disclosure No. 1 of January 1992 was used. No. 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and European Patent No. 931647 are preferable.
Specific examples of the polymer constituting the thermoplastic polymer fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and a polyalkylene structure. Mention may be made of homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.

  Examples of the heat-reactive polymer fine particles include polymer fine particles having a heat-reactive group. The thermoreactive polymer fine particles form a hydrophobized region by crosslinking by a thermal reaction and a functional group change at that time.

  The heat-reactive group in the polymer fine particle having a heat-reactive group may be any functional group that can perform any reaction as long as a chemical bond is formed. However, a polymerizable group is preferable, and an example thereof is a radical polymerization reaction. Ethylenically unsaturated groups (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable groups (for example, vinyl group, vinyloxy group, epoxy group, oxetanyl group, etc.) A functional group having an active hydrogen atom (for example, an amino group, a hydroxy group, a carboxy group, etc.), a carboxyl group that performs a condensation reaction, and a reaction partner. A certain hydroxy group or amino group, an acid anhydride that performs a ring-opening addition reaction, and an amino group or hydrogen that is a reaction partner Such proxy group are preferably exemplified.

  As the microcapsule, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, at least a part of the constituent components of the image recording layer is encapsulated in the microcapsule. The constituent components of the image recording layer can also be contained outside the microcapsules. The image recording layer containing a microcapsule is preferably configured so that a hydrophobic constituent component is encapsulated in the microcapsule and a hydrophilic constituent component is contained outside the microcapsule.

  The microgel (crosslinked polymer fine particles) can contain a part of the constituent components of the image recording layer on at least one of the surface or the inside thereof. In particular, a reactive microgel having a radical polymerizable group on its surface is preferable from the viewpoint of image forming sensitivity and printing durability.

  A known method can be applied to microencapsulate or microgel the constituent components of the image recording layer.

  The average particle size of the polymer compound in the form of fine particles is preferably 0.01 to 3.0 μm, more preferably 0.03 to 2.0 μm, and still more preferably 0.10 to 1.0 μm. In this range, good resolution and stability over time can be obtained. The average particle diameter is calculated by a laser light scattering method.

  The content of the polymer compound in the form of fine particles is preferably 5 to 90% by mass with respect to the total solid content of the image recording layer.

<Other ingredients>
The image recording layer B can contain other components described in the image recording layer A as necessary.

<Formation of image recording layer B>
Regarding the formation of the image recording layer B, the description of the formation of the image recording layer A can be applied.

  In the lithographic printing plate precursor, an undercoat layer can be provided between the image recording layer and the support, if necessary.

(Undercoat layer)
The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area and easily peels from the support of the image recording layer in the unexposed area. Contributes to improving the performance. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and lowering the sensitivity.

Specific examples of the compound used for the undercoat layer include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and JP-A-2- Examples thereof include phosphorus compounds having an ethylenic double bond reactive group described in Japanese Patent No. 304441. Preferable examples include polymer compounds having an adsorptive group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the surface of the support, as described in JP-A Nos. 2005-125749 and 2006-188038. It is done. Such a polymer compound is preferably a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group. More specifically, a phenolic hydroxyl group, a carboxyl _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - having an adsorptive group such as COCH 2 COCH ₃ Examples thereof include a copolymer of a monomer, a monomer having a hydrophilic group such as a sulfo group, and a monomer having a polymerizable crosslinkable group such as a (meth) acryl group or an allyl group. The polymer compound may have a crosslinkable group introduced by salt formation between a polar substituent of the polymer compound, a substituent having a counter charge and a compound having an ethylenically unsaturated bond. In addition, monomers other than those described above, preferably hydrophilic monomers, may be further copolymerized.

The content of unsaturated double bonds in the polymer compound for the undercoat layer is preferably 0.1 to 10.0 mmol, more preferably 2.0 to 5.5 mmol, per 1 g of the polymer compound.
The polymer compound for the undercoat layer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000.

  In addition to the above compound for the undercoat layer, the undercoat layer is a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability and an aluminum support for preventing contamination over time. A compound having a group that interacts with the surface, such as 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil, sulfophthalic acid , Hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from ^{0.1~100mg / m 2, 1~30mg / m} 2 is more preferable.

  In the planographic printing plate precursor, a protective layer can be provided on the image recording layer as necessary.

[Protective layer]
In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.

The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. it can. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specific examples include modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.

The protective layer preferably contains an inorganic layered compound in order to enhance oxygen barrier properties. The inorganic layered compound is a particle having a thin flat plate shape, for example, mica group such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hecton represented by the formula: 3MgO · 4SiO · H ₂ O Light, zirconium phosphate, etc. are mentioned.
The inorganic layered compound preferably used is a mica compound. As the mica compound, for example, the formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [where A is one of K, Na, Ca, B and C are One of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. ] Mica groups such as natural mica and synthetic mica represented by

In the mica group, natural mica includes muscovite, soda mica, phlogopite, biotite, and sericite. Synthetic fluorine phlogopite _KMg 3 as mica _(AlSi 3 O10) _{F 2,} potassium tetrasilic mica _KMg 2.5 _Si 4 _O 10) non-swellable mica ₂ such _F, and, Na tetrasilylic mica _{NaMg 2.5} (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite-based Na or Li hectorite (Na, Li) _1/8 Mg _2/5 Examples thereof include swelling mica such as Li _1/8 (Si ₄ O ₁₀ ) F ₂ . Synthetic smectite is also useful.

Of the mica compounds, fluorine-based swellable mica is particularly useful. That is, the swellable synthetic mica has a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and the substitution of metal atoms in the lattice is significantly larger than that of other clay minerals. As a result, the lattice layer is deficient in positive charge, and in order to compensate for this, cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , and Mg ²⁺ are adsorbed between the layers. The cations present between these layers are called exchangeable cations and can be exchanged with various cations. In particular, when the cation between layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swelling synthetic mica has a strong tendency and is particularly preferably used.

  As the shape of the mica compound, from the viewpoint of diffusion control, the thinner the better, the better the plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured, for example, from a projection drawing of a particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the mica compound has a mean major axis of preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. Specifically, for example, in the case of swellable synthetic mica, which is a representative compound, as a preferred embodiment, the thickness is about 1 to 50 nm and the surface size (major axis) is about 1 to 20 μm.

  0-60 mass% is preferable with respect to the total solid of a protective layer, and, as for content of an inorganic stratiform compound, 3-50 mass% is more preferable. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of the inorganic layered compounds is preferably the above content. Within the above range, the oxygen barrier property is improved and good sensitivity is obtained. Further, it is possible to prevent a decrease in inking property.

  The protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling the slipperiness of the surface. Further, the protective layer may contain the sensitizer described in the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer (solid content) is preferably from 0.01 to 10 g / ^{m 2,} more preferably ^{0.02~3g / m 2, 0.02~1g / m} 2 is particularly preferred.

[Printing method]
The printing method according to the present invention includes an on-machine development of the on-press development type lithographic printing plate dummy plate and the on-press development type lithographic printing plate precursor which are mounted on the same plate cylinder of a printing press.

In the printing method according to the present invention, the on-press development type lithographic printing plate dummy plate and the on-press development type lithographic printing plate precursor are mounted on the same plate cylinder of a printing press. As the printing machine, for example, a newspaper offset rotary printing machine (manufactured by Tokyo Machine Works, Ltd. or Mitsubishi Heavy Industries, Ltd.) is used.
Thereafter, printing is performed by a normal method. That is, when dampening water and printing ink are supplied, the constituent layers of the on-press development type lithographic printing plate dummy plate and on-press development type lithographic printing plate precursor are dissolved or dissolved by the supplied dampening water and / or printing ink. After being dispersed and removed, the surface of the hydrophilic aluminum support or the aluminum support having the hydrophilic constituent layer 1 or the undercoat layer component adsorbed on the surface is exposed. As a result, the fountain solution adheres to the exposed hydrophilic surface and the printing ink is prevented from adhering.
Here, the surface of the on-press development type lithographic printing plate dummy plate and on-press development type lithographic printing plate precursor may be supplied with dampening water or printing ink. In order to promote the on-press developability of the layer, it is preferable to supply fountain solution first.

The on-press development type lithographic printing plate precursor is subjected to image exposure according to a conventional method before being mounted on a plate cylinder of a printing press. Image exposure is preferably performed by a method of scanning exposure of digital data with an infrared laser or the like.
The wavelength of the exposure light source is preferably 750 to 1,400 nm. As a light source of 750 to 1,400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.
Image exposure can be performed by a known method using a plate setter or the like. Moreover, after mounting the on-press development type lithographic printing plate precursor on a printing machine using a printing machine equipped with an exposure device, exposure may be performed on the printing machine.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the polymer compound, unless otherwise specified, the molecular weight is a mass average molecular weight (Mw) in terms of polystyrene converted by a gel permeation chromatography (GPC) method, and the ratio of repeating units is a mole percentage. Further, “part” and “%” mean “part by mass” and “% by mass” unless otherwise specified.

[Examples 1-37 and Comparative Examples 1-4]
[Preparation of on-press development type lithographic printing plate dummy]

<Preparation of aluminum support>
The following treatments (a) to (m) were applied to an aluminum alloy plate having a thickness shown in Table A having a composition shown in Table A to prepare a support. In addition, the water washing process was performed between all the process steps, and the liquid draining was performed with the nip roller after the water washing process.

(A) Mechanical roughening treatment (brush grain method)
Using a device as shown in FIG. 1, mechanical roughening by a rotating bundle-planting brush while supplying a suspension of pumice (specific gravity 1.1 g / cm ³ ) as an abrasive slurry to the surface of an aluminum plate. Processed. In FIG. 1, 41 is an aluminum plate, 42 and 44 are roller brushes (bundle brushes), 43 is a polishing slurry liquid, and 45, 46, 47 and 48 are support rollers.

  The mechanical surface roughening treatment was performed with the median diameter of the abrasive pumice being 30 μm, the number of bundled brushes being 4, and the number of rotations of the bundled brush being 250 rpm. The material of the bunch planting brush was 6 · 10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The bundle-planting brush is a tube made by making a hole in a stainless steel tube of φ300 mm so as to be dense. The distance between the two support rollers (φ200 mm) at the bottom of the bundle-planting brush was 300 mm. The bundle brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus with respect to the load before the bundle brush was pressed against the aluminum plate. The rotation direction of the bundle planting brush was the same as the movement direction of the aluminum plate.

(B) Alkaline etching treatment An aluminum plate was etched with an aqueous caustic soda solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% by spraying at a temperature of 70 ° C. Then, water washing by spraying was performed. The amount of dissolved aluminum was 10 g / m ² .

(C) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous nitric acid solution. The nitric acid aqueous solution used for the electrochemical roughening in the next step was used as the nitric acid aqueous solution used for the desmut treatment. The liquid temperature was 35 ° C. The desmutting treatment was performed by spraying a desmutting solution for 3 seconds.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. As the electrolytic solution, an electrolytic solution in which aluminum nitrate was added to an aqueous solution having a temperature of 35 ° C. and nitric acid was 10.4 g / L to adjust the aluminum ion concentration to 4.5 g / L was used. The AC power supply waveform is subjected to electrochemical surface roughening using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time tp of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 2 was used. In FIG. 2, an aluminum plate W is wound around a radial drum roller 52 disposed so as to be immersed in the main electrolytic cell 50, and subjected to electrolytic treatment by main electrodes 53a and 53b connected to an AC power source 51 in the course of conveyance. The electrolytic solution 55 was supplied from the electrolytic solution supply port 54 through the slit 56 to the electrolytic solution passage 57 between the radial drum roller 52 and the main electrodes 53a and 53b. The aluminum plate W treated in the main electrolytic cell 50 was then electrolytically treated in the auxiliary anode cell 60. An auxiliary anode 58 is disposed opposite to the aluminum plate W in the auxiliary anode tank 60, and the electrolytic solution 55 is supplied so as to flow in the space between the auxiliary anode 58 and the aluminum plate W. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity was 185 C / dm ^{2 as} the total amount of electricity when the aluminum plate was an anode. Then, water washing by spraying was performed.

(E) Alkaline etching treatment An aluminum plate was etched by spraying an aqueous caustic soda solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of dissolved aluminum was 0.5 g / m ² .

(F) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. In the desmutting treatment, an aqueous sulfuric acid solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L was used. The liquid temperature was 60 ° C. The desmutting treatment was performed by spraying a desmutting solution for 3 seconds.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. As the electrolytic solution, an electrolytic solution in which aluminum chloride was adjusted to 4.5 g / L by adding aluminum chloride to an aqueous solution having a liquid temperature of 35 ° C. and hydrochloric acid of 6.2 g / L was used. The AC power supply waveform is subjected to electrochemical surface roughening using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time tp of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 2 was used. The current density was 25A / dm ² at the peak of electric current amount in hydrochloric acid electrolysis of the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode. Then, water washing by spraying was performed.

(H) Alkaline etching treatment An aluminum plate was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of aluminum dissolved was 0.1 g / m ² .

(I) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. Using an aqueous sulfuric acid solution used in the anodizing treatment step (containing 5 g / L of aluminum ions in an aqueous solution of 170 g / L sulfuric acid), desmut treatment was performed at a liquid temperature of 35 ° C. for 4 seconds. The desmutting liquid was sprayed and sprayed for 3 seconds.

(J) First Anodizing Treatment A first stage anodizing treatment was performed using a direct current electrolysis anodizing apparatus having the structure shown in FIG. Anodization was performed under the conditions shown in Table B to form an anodized film having a predetermined film thickness. As the electrolytic solution, an aqueous solution containing the components shown in Table B was used. In Tables B to D, “component concentration” represents the concentration (g / l) of each component described in the “Liquid component” column.

  In the anodizing apparatus 610 shown in FIG. 3, the aluminum plate 616 is conveyed as shown by the arrows in FIG. The aluminum plate 616 is charged (+) by the power supply electrode 620 in the power supply tank 612 in which the electrolytic solution 618 is stored. Then, the aluminum plate 616 is conveyed upward by the roller 622 in the power supply tank 612, and the direction is changed downward by the nip roller 624. Then, the aluminum plate 616 is conveyed toward the electrolytic treatment tank 614 in which the electrolytic solution 626 is stored, and by the roller 628. The direction is changed horizontally. Next, the aluminum plate 616 is charged to (−) by the electrolytic electrode 630 to form an anodized film on the surface thereof, and the aluminum plate 616 exiting the electrolytic treatment tank 614 is transported to a subsequent process. In the anodizing apparatus 610, the direction changing means is constituted by the roller 622, the nip roller 624 and the roller 628. Thus, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 620 and the electrolytic electrode 630 are connected to a DC power source 634.

(K) Second Anodizing Treatment A second stage anodizing treatment was performed using a direct current electrolysis anodizing apparatus having the structure shown in FIG. Anodization was performed under the conditions shown in Table C to form an anodized film having a predetermined film thickness. As the electrolytic solution, an aqueous solution containing the components shown in Table C was used.

(L) Third Anodizing Treatment A third stage anodizing treatment was performed using a direct current electrolysis anodizing apparatus having the structure shown in FIG. Anodization was performed under the conditions shown in Table D to form an anodized film having a predetermined film thickness. As the electrolytic solution, an aqueous solution containing the components shown in Table D was used.

(M) Hydrophilization treatment In order to ensure the hydrophilicity of the non-image area, a silicate treatment was performed by dipping at 50 ° C. for 7 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution. The adhesion amount of Si was 8.5 mg / m ² . Then, water washing by spraying was performed.

  The average diameter (surface layer average diameter) of the large-diameter hole portion in the anodic oxide film having the micropores obtained above, the average diameter (bottom average diameter) at the communicating position of the large-diameter hole portion, and the small-diameter hole Average diameter (small-diameter hole diameter), average depth of large-diameter holes and small-diameter holes, thickness of anodized film from the bottom of small-diameter holes to the aluminum plate surface (barrier layer thickness), small-diameter Table E shows the hole density and the like. The small diameter hole portion includes a first small diameter hole portion and a second small diameter hole portion having different depths, and the deeper one is referred to as a first small diameter hole portion.

  In Table E, the average value and the minimum value are shown as the barrier layer thickness. The average value is obtained by measuring the thickness of the anodized film from the bottom of the first small-diameter hole to the aluminum plate surface at 50 locations and arithmetically averaging them.

The average diameter of the micropores (average diameter of the large-diameter hole portion and the small-diameter hole portion) was obtained by observing N = 4 sheets of the large-diameter hole surface and the small-diameter hole surface with an FE-SEM at a magnification of 150,000 times. In the four images, the diameters of the micropores (large-diameter holes and small-diameter holes) existing in the range of 400 × 600 nm ² were measured and averaged. In addition, when the depth of the large-diameter hole portion was deep and it was difficult to measure the diameter of the small-diameter hole portion, the upper part of the anodized film was cut, and thereafter various diameters were obtained.
The average depth of the large-diameter hole is determined by observing the cross section of the support (anodized film) with FE-TEM at a magnification of 500,000 times, and in the obtained image, the distance from the surface of any micropore to the communication position This is a value obtained by measuring 60 (N = 60) and averaging them. In addition, the average depth of the small-diameter hole portion is obtained by observing the cross section of the support (anodized film) with FE-SEM (50,000 times) and measuring the depth of 25 arbitrary micropores in the obtained image. The average value.

“Communication density” means the density of small-diameter holes in the cross-section of the anodized film. “Surface area increase ratio” means a value calculated based on the following formula (A).
Formula (A)
Surface area increase ratio = 1 + pore density × (π × (surface layer average diameter / 2 + bottom portion average diameter / 2) × ((bottom portion average diameter / 2−surface layer average diameter / 2) ² + depth A ² ) ^1/2 + π × (Bottom average diameter / 2) ² −π × (surface layer average diameter / 2) ² )
In the “average depth (nm)” column of the small diameter hole portion, the average depth of the second small diameter hole portion is shown on the left side, and the average depth of the first small diameter hole portion is shown on the right side. In the “communication density” column of the small diameter hole in Table E, the density of the first small diameter hole is shown in parentheses together with the communication density of the small diameter hole.
Further, the average diameter of the first small-diameter holes located from the bottom of the second small-diameter holes to the bottom of the first small-diameter holes was about 12 nm.

<Preparation of coating solution for component layer 1>
Constituent layer 1 coating solutions d-1 to d-9 and a-1 having the following compositions were prepared.
(Structure layer 1 coating liquid d-1)
-High molecular compound F-1 (following structure) 3.6g
・ Low molecular weight hydrophilic compound G-3 (below) 0.1 g
・ Water 100.0g

In the polymer compound F-1, M ¹ , M ² , and M ³ each independently represent a hydrogen atom or a sodium atom. The number on the right side of the parenthesis represents the content (mol%) of each monomer unit with respect to the total monomer units of the polymer compound.

(Structure layer 1 coating liquid d-2)
-High molecular compound F-1 (above) 3.6 g
・ Low molecular weight hydrophilic compound G-1 (below) 0.72 g
・ Low molecular weight hydrophilic compound G-3 (below) 0.1 g
・ Water 100.0g

(Structure layer 1 coating liquids d-3 to d-7)
Component layer 1 coating liquids d-3 to d-7 are prepared by adjusting low molecular weight hydrophilic compounds G-2 to G-6 instead of low molecular weight hydrophilic compound G-1 in the preparation of component layer 1 coating liquid d-2. Was prepared in the same manner except that each was used.

(Structure layer 1 coating solution d-8)
The composition layer 1 coating solution d-8 was prepared in the same manner except that 0.1 g of the compound H-1 (colorant) was further added in the preparation of the composition layer 1 coating solution d-2.

  Compound H-1: Acid Red 73 (trade name: WATER RED 3, manufactured by Orient Chemical Co., Ltd.) (the following structure)

(Structure layer 1 coating liquid d-9)
Component layer 1 coating solution d-9 was prepared in the same manner as in the preparation of component layer 1 coating solution d-2 except that 0.72 g (in terms of solid content) of fine particle D-2 microgel was added. did.

The low molecular weight hydrophilic compounds G-1 to G-6 are the compounds shown below.
Low molecular weight hydrophilic compound G-1: Anionic surfactant, 4- (2- (2- (2-ethylhexyloxy) ethoxy) ethoxy) butane-1-sulfonic acid sodium, manufactured by Wako Pure Chemical Industries, Ltd. molecular hydrophilic compound G-2: anionic surfactants, sodium naphthalene sulfonate, manufactured by Wako Pure chemical Industries, Ltd. hydrophilic low molecular weight compound G-3: a nonionic _surfactant, C ₁₂ H 25 - (OCH ₂ CH _{2) 10} -OH, EMALEX 710, manufactured by Nippon emulsion Co. hydrophilic low molecular weight compound G-4: sulfophthalic acid (50 wt%)
Low molecular weight hydrophilic compound G-5: Malic acid, manufactured by Fuso Chemical Industry Co., Ltd. Low molecular weight hydrophilic compound G-6: Trimethylammonium acetate, manufactured by Iwase Kosfa Co., Ltd.

(Preparation of fine particle D-2 microgel)
As an oil phase component, 4.46 g of a polyfunctional isocyanate (75% by mass ethyl acetate solution manufactured by Mitsui Chemicals, Inc.) having the following structure, trimethylolpropane (6 mol) and xylene diisocyanate (18 mol) were added. , 10 g of an adduct obtained by adding methyl-terminated polyoxyethylene (1 mole, repeating number of oxyethylene units: 90) to this (Mitsui Chemicals Polyurethanes Co., Ltd., 50 mass% ethyl acetate solution), pentaerythritol triacrylate (SR444, Nippon Kayaku Co., Ltd.) 3.15 g and Pionein A-41C (Takemoto Yushi Co., Ltd.) 0.1 g were dissolved in ethyl acetate 17 g. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The solid content concentration of the microgel solution thus obtained was diluted with distilled water so as to be 15% by mass to prepare fine particle D-2 microgel. The average particle diameter of the fine particles D-2 measured by the light scattering method was 0.2 μm.

(Structure layer 1 coating liquid a-1)
-High molecular compound A-1 (following structure) 0.18g
・ Hydroxyethyliminodiacetic acid 0.05g
・ Low molecular weight hydrophilic compound G-3 0.03g
・ Water 28.0g

<Formation of Component Layer 1-1 to Component Layer 1-10>
On the support, the composition layer 1 coating solution d-1 is bar-coated so that the dry coating amount is 500 mg / m ^2, and dried at 100 ° C. for 1 minute using a thermostat PH-201 manufactured by Espec. Thus, the constituent layer 1-1 was formed.
On the support, the composition layer 1 coating liquids d-2 to d-7 are bar-coated so that the dry coating amount is 600 mg / m ^2, and the temperature is 100 ° C. using a thermostat PH-201 manufactured by Espec Corporation. And dried for 1 minute to form constituent layers 1-2 to 1-7, respectively.
On the support, the composition layer 1 coating solution d-8 was applied to a bar so that the dry coating amount was 615 mg / m ^2, and dried at 100 ° C. for 1 minute using a thermostat PH-201 manufactured by Espec Corporation. Thus, the constituent layer 1-8 was formed.
On the support, the composition layer 1 coating solution d-9 was applied with a bar so that the dry coating amount was 600 mg / m ^2, and dried at 100 ° C. for 1 minute using a thermostat PH-201 manufactured by ESPEC CORP. Thus, the constituent layer 1-9 was formed.
On the support, the composition layer 1 coating solution a-1 is bar-coated so that the dry coating amount is 20 mg / m ^2, and dried at 100 ° C. for 1 minute using a thermostat PH-201 manufactured by Espec. Thus, the constituent layer 1-10 was formed.

<Preparation of composition layer 2 coating solution>
Component layer 2 coating solutions e-1 to e-4 and b-2 having the following composition were prepared.
(Structure layer 2 coating solution e-1)
Component layer 2 coating solution e-1 was prepared by mixing and stirring the following coating solution (1) and microgel solution (1) immediately before coating.

(Coating liquid (1))
-High molecular compound B-1 (following structure) 0.240g
(Mw: 55,000, n: 2 (number of EO units))
・ Plasticizer 0.192g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Low molecular weight hydrophilic compound G-1 (above) 0.093 g
・ Fluorosurfactant (1) (the following structure) 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

(Microgel solution (1))
Fine particle D-2 microgel (above) 2.640 g
・ Distilled water 2.425g

(Structure layer 2 coating solution e-2)
The constituent layer 2 coating solution e-2 was prepared in the same manner except that the low molecular weight hydrophilic compound G-6 was used instead of the low molecular weight hydrophilic compound G-1 in the preparation of the constituent layer 2 coating solution e-1. did.

(Structure layer 2 coating solution e-3)
Component layer 2 coating solution e-3 was prepared in the same manner as in the preparation of component layer 2 coating solution e-1 except that 0.015 g of compound H-1 was further added.

(Structure layer 2 coating solution e-4)
The constituent layer 2 coating solution e-4 was prepared in the same manner as in the preparation of the constituent layer 2 coating solution e-1 except that the low molecular weight hydrophilic compound G-1 was excluded.

(Structure layer 2 coating solution b-2)

  Component layer 2 coating solution b-2 was prepared by mixing and stirring the following coating solution (2) and microgel solution (1) immediately before coating.

(Coating solution (2))
・ Polymer compound B-1 (above) 0.240 g
・ Infrared absorber (1) (the following structure) 0.020 g
Borate compound (1) 0.010 g
Sodium tetraphenylborate-polymerization initiator (1) (the following structure) 0.162 g
・ Plasticizer 0.192g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Low molecular weight hydrophilic compound G-1 (above) 0.050 g
・ Fluorosurfactant (1) (above) 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

(Microgel solution (1))
Fine particle D-2 microgel (above) 2.640 g
・ Distilled water 2.425g

<Formation of constituent layer 2-1 to constituent layer 2-5>
As shown in Table 1 below, on the constituent layer 1, the constituent layer 2 coating liquids e-1 to e-4 and b-2 are bar-coated so that the dry coating amount is 1.0 g / m ^2. Using a thermostat PH-201 manufactured by Co., Ltd., drying was performed at 125 ° C. for 75 seconds to form component layers 2-1 to 2-5, respectively.

<Preparation of coating solution for component layer 3>
Composition layer 3 coating solutions f-1 to f-8 and c-1 having the following compositions were prepared.
(Structure layer 3 coating solution f-1)
・ Synthetic mica (Somasif ME-100, 8% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.)
0.82g
・ Polymer I-1 (below) 0.52 g
・ Carboxymethylcellulose (Serogen PR, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.22 g
・ Low molecular weight hydrophilic compound G-7 (below) 0.02g
・ Low molecular weight hydrophilic compound G-3 (above) 0.04 g
・ Low molecular weight hydrophilic compound G-1 (above) 0.18 g
・ Ion-exchanged water 36.40g

The polymer I-1 is polyvinyl alcohol (CKS-50, saponification degree 99 mol%, polymerization degree 300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).
The low molecular weight hydrophilic compound G-7 is a nonionic surfactant (Pluronic P84, manufactured by BASF).

(Structure layer 3 coating solutions f-2 to f-6)
Component layer 3 coating liquids f-2 to f-6 are prepared by adjusting low molecular weight hydrophilic compounds G-2 to G-6 instead of low molecular weight hydrophilic compound G-1 in the preparation of component layer 3 coating liquid f-1. Was prepared in the same manner except that each was used.

(Structure layer 3 coating solution f-7)
Component layer 3 coating solution f-7 was prepared in the same manner except that 0.015 g of compound H-1 (colorant) was further added in the preparation of component layer 3 coating solution f-1.

(Structure layer 3 coating solution f-8)
The composition layer 3 coating solution f-8 was prepared in the same manner as the composition layer 3 coating solution f-1, except that the low molecular weight hydrophilic compounds G-7, G-3 and G-1 were excluded.

(Structure layer 3 coating liquid c-1)
・ Inorganic layered compound dispersion (1) (below) 1.5 g
-Polymer E-1 (the following structure, Mw: 30,000) (solid content) 0.03 g
-Polymer I-1 (above) (6% by mass aqueous solution) 0.10 g
-Polymer I-2 (below) (6 mass% aqueous solution) 0.03 g
Low molecular weight hydrophilic compound G-3 (above) (1% by mass aqueous solution) 0.86 g
・ Ion-exchanged water 6.0g

  The polymer I-2 is polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd., saponification degree 81.5 mol%, polymerization degree 500).

<Formation of constituent layer 3-1 to constituent layer 3-9>
As shown in Table 1 below, on the constituent layer 1, the constituent layer 3 coating liquids f-1 to f-8 were bar-coated so that the dry coating amount was 1.8 g / m ^2, and manufactured by ESPEC CORP. It dried at 125 degreeC for 75 second using thermostat PH-201, and formed the structural layer 3-1 to the structural layer 3-8, respectively (Examples 1-15 and 20-34, and Comparative Examples 1 and 3). .
Further, as shown in Table 1 below, on the constituent layer 2, the constituent layer 3 coating liquid c-1 was applied with a bar so that the dry coating amount was 0.15 g / m ^2, and a thermostat made by Espec Co., Ltd. It dried at 120 degreeC for 60 second using PH-201, and the structural layer 3-9 was formed (Examples 16-19 and 35-37, and Comparative Examples 2 and 4).

Using the aluminum support, the constituent layer 1, the constituent layer 2, and the constituent layer 3, on-press development type lithographic printing plate dummy plates 1 to 19 having the constitution shown in Table 1 below were prepared.
The on-press development type lithographic printing plate dummy plates 1 to 7 have a two-layer structure having the constituent layer 1 and the constituent layer 3 on the support, and the constituent layer 3 contains a low molecular weight hydrophilic compound.
The on-press development type lithographic printing plate dummy plates 8 to 15 have a two-layer structure having the constituent layer 1 and the constituent layer 3 on the support, and the constituent layer 1 contains a low molecular weight hydrophilic compound.
The on-press development type lithographic printing plate dummy plates 16 to 19 have a three-layer structure in which the supporting layer includes the constituent layer 1, the constituent layer 2, and the constituent layer 3, and the constituent layer 2 contains a low molecular weight hydrophilic compound.
The on-press development type lithographic printing plate dummy plate R-1 for comparison has a two-layer structure having a constituent layer 1 and a constituent layer 3 on a support, and both the constituent layer 1 and the constituent layer 3 have low molecular hydrophilicity. Contains no compounds.
The on-press development type lithographic printing plate dummy plate R-2 for comparison has a three-layer structure having a constituent layer 1, a constituent layer 2 and a constituent layer 3 on a support, and any of constituent layers 1 to 3 is included. Does not contain low molecular weight hydrophilic compounds.

[Preparation of on-press development type lithographic printing plate precursor]

<Aluminum support>
The aluminum support used in the production of the on-press development type lithographic printing plate dummy plate was used.

<Formation of undercoat layer 1>
As shown in Table 1 below, the undercoat layer coating solution a-1 having the following composition was applied to a bar so that the dry coating amount was 20 mg / m ^2, and the temperature was adjusted to 100 ° C. using a thermostat PH-201 manufactured by Espec Co., Ltd. The undercoat layer 1 was formed by drying for 1 minute.

(Undercoat layer coating solution a-1)
・ Undercoat layer compound (1) (the following structure) 0.18 g
・ Hydroxyethyliminodiacetic acid 0.05g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.03g
・ Water 28.0g

<Formation of Image Recording Layer 1>
As shown in Table 1 below, the image recording layer coating liquid b-1 having the following composition was applied to a bar so that the dry coating amount was 0.6 g / m ² , and then using a thermostat PH-201 manufactured by Espec Corporation. The image recording layer 1 was formed by drying at 125 ° C. for 75 seconds.

(Image recording layer coating solution b-1)
-Thermoplastic polymer fine particle water dispersion (below) 20.0g
・ Infrared absorber (structure below) 0.2g
・ Polymerization initiator (structure below) 0.55g
-Polymerizable compound (structure shown below) 1.50 g
・ Mercapto-3-triazole 0.2g
・ Black-15 (the following structure) 0.2g
・ Klucel M (Hercules) 4.8g
-Anionic surfactant 1 (the following structure) 0.15 g
・ N-propanol 55.0g
・ 2-butanone 17.0g

(Preparation of aqueous dispersion of thermoplastic polymer fine particles)
A 1000 ml four-necked flask was equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube and reflux condenser, and while introducing nitrogen gas to perform deoxygenation, polyethylene glycol methyl ether methacrylate (PEGMA, ethylene glycol) Average repeating unit number: 20) 10 g, distilled water 200 g and n-propanol 200 g were added and heated until the internal temperature reached 70 ° C. Next, a mixture of 10 g of styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization proceeded at 98% or more at the stage of reaction for a total of 20 hours, and an aqueous dispersion of thermoplastic polymer fine particles having a mass ratio of PEGMA / St / AN = 10/10/80 was obtained. The particle size distribution of the thermoplastic polymer fine particles had a maximum value at a volume average particle size of 150 nm.

  The above particle size distribution is obtained by taking an electron micrograph of thermoplastic polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between the maximum value of the obtained particle size measurement values and zero. And the frequency of appearance of each particle size was plotted and obtained. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was taken as the particle size.

  The structures of the infrared absorber, polymerization initiator, polymerizable compound, Black-15, and anionic surfactant 1 used in the image recording layer coating solution b-1 are shown below.

  Klucel M used for the image recording layer coating liquid b-1 is hydroxypropyl cellulose (2% by mass aqueous solution).

<Formation of Image Recording Layer 2>
As shown in Table 1 below, the image recording layer coating solution b-2 having the following composition was applied to a bar so that the dry coating amount was 1.0 g / m ^2, and the temperature chamber PH-201 manufactured by Espec Co., Ltd. was used. The image recording layer 2 was formed by drying at 125 ° C. for 75 seconds.
The image recording layer coating solution b-2 was prepared by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

(Photosensitive solution (1))
-Binder polymer (1) (the following structure) 0.240 g
(Mw: 55,000, n: 2 (number of EO units))
・ Infrared absorber (1) (the following structure) 0.020 g
Borate compound (1) 0.010 g
Sodium tetraphenylborate-polymerization initiator (1) (the following structure) 0.162 g
・ Polymerizable compound 0.192g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Anionic surfactant 1 (above) 0.050 g
・ Fluorosurfactant (1) (the following structure) 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

(Microgel solution (1))
-Microgel (1) (below) 2.640 g
・ Distilled water 2.425g

  The structures of the binder polymer (1), infrared absorber (1), polymerization initiator (1) and fluorine-based surfactant (1) used in the image recording layer coating liquid b-2 are shown below.

(Preparation of microgel (1))
As an oil phase component, 4.46 g of a polyfunctional isocyanate (75% by mass ethyl acetate solution manufactured by Mitsui Chemicals, Inc.) having the following structure, trimethylolpropane (6 mol) and xylene diisocyanate (18 mol) were added. , 10 g of an adduct obtained by adding methyl-terminated polyoxyethylene (1 mole, repeating number of oxyethylene units: 90) to this (Mitsui Chemicals Polyurethanes Co., Ltd., 50 mass% ethyl acetate solution), pentaerythritol triacrylate (SR444, Nippon Kayaku Co., Ltd.) 3.15 g and Pionein A-41C (Takemoto Yushi Co., Ltd.) 0.1 g were dissolved in ethyl acetate 17 g. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. A microgel (1) was prepared by diluting the solid content concentration of the microgel solution thus obtained with distilled water so as to be 15% by mass. The average particle size of the microgel measured by the light scattering method was 0.2 μm.

<Formation of protective layer 1>
As shown in Table 1 below, the protective layer coating solution (c-1) having the following composition was bar coated and then oven-dried at 120 ° C. for 60 seconds to form a protective layer 1 having a dry coating amount of 0.15 g / m ^2. Formed.

(Coating liquid for protective layer (c-1))
・ Inorganic layered compound dispersion (1) (below) 1.5 g
-Hydrophilic polymer (1) (the following structure, Mw: 30,000) (solid content) 0.03 g
-Polyvinyl alcohol (CKS50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.,
Sulfonic acid modification, saponification degree 99 mol% or more, polymerization degree 300)
0.10 g of 6% by weight aqueous solution
・ Polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd.,
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.)
(The following structure) 1 mass% aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using a homogenizer until the volume average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

An on-press development type lithographic printing plate precursor 1 was prepared by forming an image recording layer 1 on the aluminum support. The on-press developing lithographic printing plate precursor 1 is an on-press developing lithographic printing plate precursor having only an image recording layer on an aluminum support.
On the aluminum support, an undercoat layer 1, an image recording layer 2, and a protective layer 1 were formed in this order to prepare an on-press development type lithographic printing plate precursor 2. The on-press development type lithographic printing plate precursor 2 is an on-press development type lithographic printing plate precursor having an undercoat layer, an image recording layer and a protective layer on an aluminum support.

  The above-described on-press development type lithographic printing plate precursors 1 and 2 and on-press development type lithographic printing plate dummy plates 1 to 19 were combined as shown in Table 1 below, and the following evaluation was performed.

<Evaluation of on-press developability>
10 sheets of on-press development type lithographic printing plate precursor (10 × 60 cm) were conditioned for 2 hours in an environment of 25 ° C. and 60% RH, sandwiched with interleaving paper, and sequentially laminated to form a laminate. This laminate was hermetically packaged with kraft paper having an aluminum laminate layer, and was allowed to stand at 60 ° C. for 3 days.
Thereafter, the on-press development type lithographic printing plate precursor was set on a Trendsetter 3244 manufactured by Creo, and image exposure was performed under the conditions of a resolution of 2400 dpi, an output of 7 W, an outer drum rotational speed of 150 rpm, and a plate surface energy of 110 mJ / cm ² . One on-press development type lithographic printing plate precursor after image exposure and one on-press development type lithographic printing plate dummy plate are mounted on the same plate cylinder of an offset rotary printing press and used as ink printing ink for newspapers. Using Soybee KKST-S (Red) manufactured by Co., Ltd. and Eco Seven N-1 manufactured by Sakata Inx Co., Ltd. as dampening water, printing was performed on newsprint at a speed of 100,000 sheets / hour. On-press developability of on-press development type lithographic printing plate precursor and on-press development type lithographic printing plate dummy plate by sampling 50th printed matter after ink supply in the printing process and visually observing the degree of contamination Was evaluated according to the following levels. The evaluation results are shown in Table 1. 5 to 3 are acceptable levels.
5: Dirt is not recognized at all.
4: Intermediate level between 5 and 3.
3: Dirt is slightly recognized.
2: Intermediate level between 3 and 1: 1: Dirt is clearly visible.

<Evaluation of development residue adhesion>
In the above printing process, the printing machine is temporarily stopped, and the development residue on the 100th printed material, on the ink kneading roller, on the blanket, on the on-press development type lithographic printing plate precursor, on the on-press development type lithographic printing plate dummy plate The adhesion state of the (solid development removed product) was observed at a magnification of 500 times using a microscope (VHX-100, zoom lens VH-Z150, manufactured by Keyence Corporation). The results were evaluated according to the following levels, and the inferior level among the levels evaluated for each of the above observation points is shown in Table 1. 5 to 3 are acceptable levels.
5: There is no development residue adhesion.
4: Very little development residue less than 10 μm adheres.
3: Very little development residue of 10 μm or more and less than 50 μm adheres.
2: Development residue of 10 μm or more and less than 50 μm is considerably attached, or development residue of 50 μm or more is attached.
1: Development debris of 100 μm or more adheres and can be easily confirmed with the naked eye.

  From the results shown in Table 1, an on-press development type lithographic printing plate precursor having an image recording layer containing a polymerization initiator containing an organic boron-containing anion is used as an on-press development type having a constituent layer containing a low molecular weight hydrophilic compound. It is apparent that the on-press development on the same plate cylinder of the printing press together with the planographic printing plate dummy prevents the on-press developability of the on-press development type lithographic printing plate precursor from being deteriorated. It can also be seen that the development debris due to on-press development is suppressed.

41 Aluminum plate 42, 44 Roller brush 43 Polishing slurry liquid 45, 46, 47, 48 Support roller 50 Main electrolytic cell 51 AC power supply 52 Radial drum roller 53a, 53b Main electrode 54 Electrolyte supply port 55 Electrolytic solution 56 Slit 58 Auxiliary Anode 60 Auxiliary anode tank W Aluminum plate 610 Anodizing apparatus 612 Power supply tank 614 Electrolytic treatment tank 616 Aluminum plate 618, 626 Electrolytic solution 620 Power supply electrode 622, 628 Roller 624 Nip roller 630 Electrode electrode 632 Tank wall 634 DC power supply

Claims (15)

  An on-press development type lithographic printing plate dummy having at least one constituent layer on an aluminum support, mounted on the same plate cylinder of a printing press, and containing a low molecular weight hydrophilic compound in at least one of the constituent layers A printing method comprising the step of on-press development of an on-press development type lithographic printing plate precursor having a plate and an image recording layer containing a polymerization initiator containing an organic boron-containing anion on an aluminum support.   The printing according to claim 1, wherein the constituent layer in contact with the aluminum support among the constituent layers contains a water-soluble polymer compound containing a repeating unit having a support-adsorbing group and a repeating unit having a hydrophilic group. Method.   The water-soluble polymer compound is selected from a monomer unit having at least one group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group and salts thereof, a sulfonic acid group and a salt thereof, an amide group, and a betaine structure. The printing method according to claim 2, which is a copolymer comprising at least one monomer unit having at least one group or structure.   The printing method according to claim 1, wherein the low molecular weight hydrophilic compound is a surfactant.   The printing method according to claim 4, wherein the surfactant is a sulfonate anionic surfactant.   The printing method according to claim 1, wherein at least one of the constituent layers contains fine particles.   The printing method according to any one of claims 1 to 6, wherein at least one of the constituent layers contains a colorant having an absorption maximum at 350 to 800 nm.   The printing method according to any one of claims 1 to 7, wherein the on-press development type lithographic printing plate dummy plate has two constituent layers.   The printing method according to any one of claims 1 to 7, wherein the on-press development type lithographic printing plate dummy plate has three constituent layers.   The printing method according to any one of claims 1 to 9, wherein the polymerization initiator is an iodonium compound containing an organic boron-containing anion and a diaryl iodonium cation.   The printing method according to claim 1, wherein the image recording layer contains polymer fine particles.   The printing method according to claim 11, wherein the polymer fine particles are particles of a copolymer containing styrene and acrylonitrile.   The printing method according to claim 11, wherein the polymer fine particle is a microgel.   The printing method according to any one of claims 1 to 13, wherein the on-press development type lithographic printing plate precursor has an undercoat layer between the aluminum support and the image recording layer.   The printing method according to claim 1, wherein the on-press development type lithographic printing plate precursor has a protective layer on the image recording layer.

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