JP2018086798A - Method for printing on planographic printing plate original, and apparatus for printing on planographic printing plate original - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for printing on a planographic printing plate original, and an apparatus for printing on a planographic printing plate original.SOLUTION: The present invention relates to a method for printing on a planographic printing plate original, including: a step of preparing a planographic printing plate original for on-press development, the original including an exposed portion subject to image-like exposure and a nonexposed portion, a color difference ΔE in the Labcolor space between the exposed portion and the nonexposed portion calculated by the formula below being 2 or more and 8 or less; an imaging step of converting first information comprising the exposed portion and the nonexposed portion into first electronic information; a processing step of converting the first electronic information into second electronic information; and a printing step of printing second information on the planographic printing plate original based on the second electronic information. Formula: ▵E=((L2-L1)+(a2-a1)+(b1-b2)), where L1, a1, and b1represent values for the exposed portion, and L2, a2, and b2represent values for the nonexposed portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printing method for a lithographic printing plate precursor and a printing apparatus for a lithographic printing plate precursor.

  With the progress of image processing technology using a computer, a lithographic printing plate precursor is now obtained by a CTP (Computer to plate) system. For example, in a CTP system, a lithographic printing plate precursor is directly imagewise exposed using a solid-state laser or a semiconductor laser diode based on printing data, and then a non-image part is removed by development. It has gained. The lithographic printing plate precursor thus obtained is mounted on the plate cylinder of a printing machine, and printing is performed on the printing paper.

  In recent years, a so-called “on-press development” method has been proposed in order to reduce an environmental load such as waste liquid processing accompanying development processing. In the on-press development, after the lithographic printing plate precursor is imagewise exposed, the conventional development is not performed, and the lithographic printing plate precursor is mounted on the plate cylinder of the printing machine, and the non-image portion is removed by dampening water or the like.

  The above-described lithographic printing plate precursor for on-press development is mounted on a plate cylinder of a printing press in an imagewise exposed state. In an image-wise exposed state, the density difference between the image area and the non-image area of the lithographic printing plate precursor, that is, the density difference between the exposed area and the non-exposed area is small. Compared to, the plate inspection becomes difficult. For this reason, there is a concern that the lithographic printing plate precursor may be erroneously mounted when it is mounted on the plate cylinder of the printing press.

  Several methods have been proposed as techniques for preventing erroneous mounting when a planographic printing plate precursor is mounted on a plate cylinder of a specified printing press. For example, in Patent Document 1, information on the position of a mounting cylinder on a plate cylinder is marked on the surface of a lithographic printing plate precursor by an ink jet recording method using a water-based ink containing a water-based dye and a water-based fixing agent. A method of mounting a lithographic printing plate precursor on a predetermined position of a plate cylinder based on information is disclosed.

  Further, Patent Document 2 discloses that after exposing a lithographic printing plate precursor for on-press development, printing plate information directly on the lithographic printing plate precursor.

JP-A-10-166552 JP 2007-086564 A

  However, the technique described in Patent Document 1 is intended for a lithographic printing plate precursor produced by imagewise exposing and developing a lithographic printing plate precursor, that is, a lithographic printing plate precursor. Patent Document 1 does not prevent erroneous mounting of a lithographic printing plate precursor for on-press development when the lithographic printing plate precursor subjected to imagewise exposure is mounted on a plate cylinder of a printing press.

  The technique described in Patent Document 2 adds plate information by directly printing on a lithographic printing plate precursor based on information from an information management server. Therefore, it is necessary to ensure that the added plate information matches the plate image of the planographic printing plate precursor. As a result, the entire system becomes larger and more complicated.

  The present invention has been made in view of such circumstances, and a printing method for a lithographic printing plate precursor capable of printing plate information on a lithographic printing plate precursor for on-press development, and a lithographic printing plate precursor for on-press development. An object of the present invention is to provide a printing apparatus.

According to one aspect of the present invention, a printing method on a lithographic printing plate precursor is a lithographic printing plate precursor comprising an exposed portion and a non-exposed portion by imagewise exposure, between the exposed portion and the non-exposed portion, First step information including a step of preparing a lithographic printing plate precursor for on-press development having a color difference ΔE in the color space of 2 to 8 in the L ^* a ^* b ^* color space determined by the following formula, and an exposed portion and a non-exposed portion An imaging step for converting the first electronic information into a first electronic information, a processing step for converting the first electronic information into second electronic information, and a printing step for printing the second information on the planographic printing plate precursor based on the second electronic information. .
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.

  Preferably, printing in the printing process is performed by an ink jet recording method using an ink containing a dye.

  Preferably, the dye is a carbonium dye.

  Preferably, the carbonium dye is at least one selected from the group of diphenylmethane dye, triphenylmethane dye, xanthene dye, and acridine dye.

  Preferably, the carbonium dye is a triphenylmethane dye.

  Preferably, the triphenylmethane dye is a triamino dye.

  Preferably, in the imaging step, the first information is irradiated with light having a wavelength of 620 nm or more and 750 nm or less, and reflected light of the light is detected.

According to another aspect of the present invention, a printing apparatus for a lithographic printing plate precursor includes an exposed portion and a non-exposed portion by imagewise exposure, and is obtained by the following formula between the exposed portion and the non-exposed portion. ^* an imaging unit for converting a ^* b ^* a first information color difference ΔE is composed of exposed area and the unexposed area of the lithographic printing plate precursor for on-press development is 2 to 8 in the color space to the first electronic information, A processing unit that converts first electronic information into second electronic information, a printing unit that prints second information on a lithographic printing plate precursor based on the second electronic information, and first electronic information transmitted from the imaging unit to the processing unit And a second transmission unit that transmits the second electronic information to the printing unit.
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.

  According to the present invention, by reading the first information printed on the lithographic printing plate precursor, it is possible to print the second information as the plate information on the lithographic printing plate precursor for on-machine development.

It is a flowchart of the printing method to a lithographic printing plate precursor. 1 is a conceptual diagram of a CTP system including a printing apparatus for a planographic printing plate precursor. It is a top view of the lithographic printing plate precursor after image-like exposure. It is the elements on larger scale of the 1st information. It is a conceptual diagram of 2nd information. It is a top view of the lithographic printing plate precursor after printing the second information.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is illustrated by the following preferred embodiments. Changes can be made by many techniques without departing from the scope of the present invention, and other embodiments than the present embodiment can be utilized. Accordingly, all modifications within the scope of the present invention are included in the claims.

  Here, in the drawing, portions indicated by the same symbols are similar elements having similar functions. In addition, in the present specification, when a numerical range is expressed using “˜”, upper and lower numerical values indicated by “˜” are also included in the numerical range.

<< Printing method on lithographic printing plate precursor >>
A printing method on a planographic printing plate precursor will be described with reference to the drawings. FIG. 1 is a flowchart of a printing method on a planographic printing plate precursor. As shown in FIG. 1, the printing method for a lithographic printing plate precursor includes a lithographic printing plate precursor preparation step (step S1), an imaging step (step S2), a processing step (step S3), and a printing step (step S4). At least.

In the lithographic printing plate precursor preparation step (step S1), an L ^* a ^* b ^* color space determined by the following formula between the exposed part and the non-exposed part, including the exposed part and the non-exposed part by imagewise exposure. A lithographic printing plate precursor for on-press development having a color difference ΔE of 2 to 8 is prepared.
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion. In the imaging step (step S2), the first information composed of the exposed part and the non-exposed part is converted into first electronic information. In the processing step (step S3), the first electronic information is converted into second electronic information. The printing process (step S4) includes a printing process for printing the second information on the planographic printing plate precursor based on the second electronic information. Hereinafter, each step will be described.

<Lithographic printing plate precursor preparation process (step S1)>
As described above, in the lithographic printing plate precursor preparation step (step S1), L ^* a obtained by the following equation between the exposed portion and the non-exposed portion, including the exposed portion and the non-exposed portion by imagewise exposure. ^* B ^* A lithographic printing plate precursor for on-press development having a color difference ΔE in the color space of 2 or more and 8 or less is prepared.
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.

  First, a planographic printing plate precursor for on-press development before imagewise exposure will be described.

[Lithographic printing plate precursor]
The lithographic printing plate precursor for on-press development of this embodiment has at least a support and an image recording layer. The lithographic printing plate precursor has an undercoat layer (sometimes referred to as an intermediate layer) between the support and the image recording layer, and a protective layer (sometimes referred to as an overcoat layer) on the image recording layer, if necessary. May be. The lithographic printing plate precursor for on-press development refers to a lithographic printing plate precursor having an image recording layer from which a non-image portion can be removed by at least one of printing ink and fountain solution on a printing press.

[Support]
A known support is used as the support for the lithographic printing plate precursor. Of these, an aluminum plate is preferable as the support. Prior to use, the aluminum plate used for the support is preferably subjected to surface treatment such as roughening treatment or anodizing treatment. The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical roughening treatment, electrochemical roughening treatment (roughening treatment that dissolves the surface electrochemically), chemical roughening treatment (roughening treatment that selectively dissolves the surface chemically) ) And the like. For these treatments, the methods described in paragraphs [0241] to [0245] of JP-A-2007-206217 can be preferably applied.

Examples of the anodizing method for the surface of the aluminum plate include sulfuric acid anodizing and phosphoric acid anodizing. The anode pore size for sulfuric acid anodization is typically less than 20 nm, whereas the anode pore size for phosphoric acid anodization is typically greater than 30 nm.
In addition, other conventional anodizing methods such as a method of producing an anode pore size larger than the anode pore size formed by sulfuric acid anodization can be used.

  In addition, a combination of acids can be used, such as a method of anodizing an aluminum plate in a mixture of acids (eg, a mixture of phosphoric acid and sulfuric acid) or anodizing sequentially using two or more acids (eg, phosphorous). An acid anodization followed by sulfuric acid anodization or vice versa is also suitable.

  The support has a center line average roughness of 0.10 to 1 from the viewpoint of good adhesion to the undercoat layer or image recording layer formed thereon, good printing durability, and good stain resistance. .2 μm is preferable. The color density of the support is preferably from 0.15 to 0.65 in terms of the reflection density value from the viewpoint of good image formation by preventing halation during imagewise exposure and good plate inspection after development. The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  In the lithographic printing plate precursor according to this embodiment, the support subjected to surface treatment such as roughening treatment or anodizing treatment in order to improve the hydrophilicity of the non-image area and prevent printing stains. It is also preferable to further hydrophilize the surface.

  As a method of hydrophilizing the surface of the support, the support is immersed in an aqueous solution of sodium silicate or the like, alkali metal silicate treatment in which it is electrolytically treated, treatment with potassium zirconate fluoride, treatment with polyvinylphosphonic acid The method etc. are mentioned, The method of immersing in the polyvinylphosphonic acid aqueous solution is used preferably.

(Image recording layer)
The image recording layer of the lithographic printing plate precursor for on-press development is an image in which the non-exposed portion, which is a non-image portion, is removed on the printing press by at least one of printing ink and neutral to alkaline fountain solution. It is a recording layer. The image recording layer according to this embodiment preferably contains an infrared absorber, a polymerizable initiator, a polymerizable compound, and a binder polymer. The fountain solution preferably has a pH of 7-11.

(Infrared absorber)
The infrared absorber has a function of converting absorbed infrared light into heat and a function of being excited by infrared light to transfer electrons and / or energy to a polymerization initiator described later. The infrared absorber used in the present embodiment is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm, and more preferably a dye.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes Is mentioned.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —N (R ⁹ ) (R ¹⁰ ), —X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different, and each may have a substituent, an aryl group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or a hydrogen atom. R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred (—NPh ₂ ). X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, a heteroaryl group, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as in, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, and a substituted or unsubstituted amino group and a halogen atom Represent.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms. R ¹ and R ² may be connected to each other to form a ring, and when a ring is formed, it is particularly preferable to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aryl group which may have a substituent. Preferred aryl groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxy groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (a) that can be preferably used include compounds described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969, and JP-A No. 2002-023360. Paragraph Nos. [0016] to [0021], and compounds described in Paragraph Nos. [0012] to [0037] of JP 2002-040638 A, preferably Paragraph Nos. [0034] to [0034] of JP 2002-278057 A. [0041], compounds described in paragraph numbers [0080] to [0086] of JP-A-2008-195018, and most preferably compounds described in paragraph numbers [0035] to [0043] of JP-A-2007-90850. Can be mentioned.

  Further, compounds described in paragraph numbers [0008] to [0009] of JP-A No. 5-5005 and paragraph numbers [0022] to [0025] of JP-A No. 2001-222101 can also be preferably used.

  Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology" (CMC Publishing, 1984) can be used.

  The particle size of the pigment is preferably 0.01 to 1 μm, 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.

(Polymerization initiator)
The polymerization initiator is a compound that initiates and accelerates the polymerization of the polymerizable compound. As the polymerization initiator, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be used.

  Specifically, examples of the polymerization initiator include (a) an organic halide, (b) a carbonyl compound, (c) an azo compound, (d) an organic peroxide, (e) a metallocene compound, and (f) an azide. Compounds, (g) hexaarylbiimidazole compounds, (h) organic borate compounds, (i) disulfone compounds, (j) oxime ester compounds, (k) onium salt compounds, and the like.

  (A) As the organic halide, compounds described in paragraph numbers [0022] to [0023] of JP-A-2008-195018 are preferable.

  (B) As the carbonyl compound, compounds described in paragraph [0024] of JP-A-2008-195018 are preferable.

  (C) As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  (D) As the organic peroxide, for example, compounds described in paragraph [0025] of JP-A-2008-195018 are preferable.

  As the (e) metallocene compound, for example, the compound described in paragraph [0026] of JP-A-2008-195018 is preferable.

  (F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.

  (G) As the hexaarylbiimidazole compound, for example, a compound described in paragraph [0027] of JP-A-2008-195018 is preferable.

  (H) As the organic borate compound, for example, a compound described in paragraph [0028] of JP-A-2008-195018 is preferable.

  (I) Examples of the disulfone compound include compounds described in JP-A No. 61-166544.

  (J) As the oxime ester compound, for example, compounds described in paragraph numbers [0028] to [0030] of JP-A-2008-195018 are preferable.

  (K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, ammonium described in US Pat. No. 4,069,055, JP-A-4-365049, and the like. Salt, phosphonium salts described in U.S. Pat. Nos. 4,069,055 and 4,069,056, EP 104,143, U.S. Patent Application Publication No. 2008/0311520 JP-A-2-150848, JP-A-2008-195018, or J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), iodonium salts, European Patent Nos. 370,693, 233,567, 297,443, 297,442, US Patent 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patents 2,904,626, 3,604,580, Sulfonium salts described in each specification of JP-A-3,604,581; V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as azinium salts described in JP-A-2008-195018.

  Among the polymerization initiators, preferred compounds include onium salts, especially iodonium salts, and sulfonium salts.

  As an example of the iodonium salt, a diphenyl iodonium salt is preferable, and a diphenyl iodonium salt substituted with an electron donating group such as an alkyl group or an alkoxyl group is particularly preferable, and an asymmetric diphenyl iodonium salt is more preferable. Specific examples include diphenyliodonium hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium hexafluorophosphate. 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium tetrafluoroborate, 4-octyloxyphenyl-2,4 , 6-trimethoxyphenyliodonium 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, bis (4-t-butyl Eniru) iodonium tetraphenylborate, and the like.

  Examples of sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium benzoylformate, bis (4-chlorophenyl) phenylsulfonium benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium tetrafluoroborate , Tris (4-chlorophenyl) sulfonium 3,5-bis (methoxycarbonyl) benzenesulfonate, tris (4-chlorophenyl) sulfonium hexafluorophosphate, and the like.

  An organic borate compound is also preferably used. Specific examples of the organic borate compound include tetraphenylborate salt, tetratolylborate salt, tetrakis (4-methoxyphenyl) borate salt, tetrakis (pentafluorophenyl) borate salt, tetrakis (3,5-bis (trifluoro) Methyl) phenyl) borate salt, tetrakis (4-chlorophenyl) borate salt, tetrakis (4-fluorophenyl) borate salt, tetrakis (2-thienyl) borate salt, tetrakis (4-phenylphenyl) borate salt, tetrakis (4-t -Butylphenyl) borate salt, ethyltriphenylborate salt, butyltriphenylborate salt and the like. From the viewpoint of achieving both printing durability, tone reproducibility, and stability over time, a tetraphenylborate salt is preferable. Examples of the counter cation of the borate compound include known cations such as alkali metal cations, alkaline earth metal cations, ammonium cations, phosphonium cations, sulfonium cations, iodonium cations, diazonium cations, and azinium cations.

  The content of the polymerization initiator is preferably from 0.1 to 50 mass%, more preferably from 0.5 to 30 mass%, particularly preferably from 0.8 to 20 mass%, based on the total solid content of the image recording layer. Within this range, better sensitivity and better stain resistance of the non-image area during printing can be obtained.

(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, i.e. dimers, trimers and oligomers, or mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable.

  As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

  Specific examples of the monomer of the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

  In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (b) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.

^{_{CH 2 = C (R 11)}} COOCH 2 CH (R 12) OH formula (b)
^{(Wherein, R 11} and ^{R 12} represent H or CH _3.)
Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide-based skeleton described in the publication, and urethane compounds having a hydrophilic group described in US Pat. No. 7,153,632, JP-T 8-505958, JP-A 2007-293221, and JP-A 2007-293223. Are also suitable.

  Among these, 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 lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 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 a polyurethane 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.

  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 is particularly preferable. An alkylene oxide structure having 1 to 9 is preferred. 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, or an alkenyl group can be introduced in order to control the inking property. For example, it can be carried out by copolymerizing a lipophilic group-containing monomer such as an alkyl methacrylate ester.

  The binder polymer preferably has a mass average molar mass (Mw) of 2000 or more, more preferably 5000 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 a specific polymer compound) in the image recording layer, 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, novolak type phenol resin, polyester Examples thereof include resins, synthetic rubbers, natural rubbers, and acrylic resins are particularly preferable.

  The specific polymer compound is substantially free of a perfluoroalkyl group. “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 the 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.

  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 (c).

In general formula (c), y is preferably 2 to 50, and more preferably 4 to 25. R ¹³ represents a hydrogen atom or an alkyl group, and R ¹⁴ 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 a pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, a 1,1-dimethylbutyl group, a 2,2-dimethylbutyl group, a cyclopentyl group, and a cyclohexyl group. In the general formula (c), R ¹³ is preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom. R ¹⁴ is particularly preferably a hydrogen atom or a methyl group.

  The specific polymer compound may have crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the polymer compound, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.

  Examples of the polymer compound having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.

Examples of the polymer compound having an ethylenically unsaturated bond in the side chain of the molecule include an ester or amide polymer compound of acrylic acid or methacrylic acid, and an ester or amide residue (-COOR or CONHR Examples thereof include a polymer compound in which R ^b ) has an ethylenically unsaturated bond.

Examples of the residue having the ethylenically unsaturated bond (the above R ^b ) include — (CH ₂ ) _n CR ¹⁵ = CR ¹⁶ R ¹⁷ , — (CH ₂ O) _n CH ₂ CR ¹⁵ = CR ¹⁶ R ¹⁷ , _{- (CH 2 CH 2 O)} n CH 2 CR 15 = CR 16 R 17, - (CH 2) n NH-CO-O-CH 2 CR 15 = CR 16 R 17, - (CH 2) n -O- ^{CO-CR 15 = CR 16 R} 17, and _{(CH 2} CH _{2 O)} in 2 -X ^(wherein each of R 15 ^{to R 16,} a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group Represents an alkoxy group or an aryloxy group, and R ¹⁵ and R ¹⁶ or R ¹⁷ may be bonded to each other to form a ring, and n represents an integer of 1 to 10. X represents dicyclopentadi. Represents an enyl residue.) And the like.

Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and, CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue) and the like.

Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Etc.

  Specific polymer compounds having crosslinkability include, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) added to the crosslinkable functional group, and polymerization is performed directly between polymer compounds. Addition polymerization is carried out through the polymerization chain of the functional compound, and a crosslink is formed between the polymer compound molecules to be cured. Alternatively, atoms in the polymer compound (for example, hydrogen atoms on the carbon atom adjacent to the functional bridging group) are extracted by free radicals to form polymer compound radicals, which are bonded to each other to form a polymer. Crosslinks are formed between the compound molecules and harden.

  The content of the crosslinkable group in the specific polymer compound (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the polymer compound. It is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

  For the purpose of improving various performances such as image strength, the specific polymer compound may further contain a copolymer component 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 (d) can be mentioned.

In the general formula (d), R ¹⁸ represents a hydrogen atom or a methyl group. R ¹⁹ represents a substituent. Preferable examples of R ¹⁹ 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 (d) 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. Acrylonitrile is preferred from the viewpoint of printing durability.

  The ratio of the repeating unit having a poly (alkylene oxide) moiety to the total repeating units constituting the specific polymer compound is not particularly limited, but is preferably 0.5 to 80 mol%, more preferably 0.5 to 50 mol. %.

  Examples of the specific polymer compound include compounds described in paragraphs [0084] to [0085] of JP-A-2015-123683. However, it is not limited to these.

  The specific 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 as required. Further, a lipophilic polymer compound and a hydrophilic polymer compound can be used in combination.

  The form of the specific polymer compound in the image recording layer may exist in the form of fine particles, in addition to being present as a binder that serves as a linking function of the image recording layer components. When present in the form of fine particles, the average particle size is in the range of 10 to 1000 nm, preferably in the range of 20 to 300 nm, and particularly preferably in the range of 30 to 120 nm.

  The content of the specific polymer compound is preferably 3 to 90% by mass, more preferably 5 to 80% by 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 JP-A-2012-148555 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.

  The polymerizable group is preferably an ethylenically unsaturated group such as a (meth) acryl group, a vinyl group, an allyl group, or a styryl group, or an epoxy group, and a (meth) acryl group, a vinyl group, or a styryl group is polymerizable. In view of the above, 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. These groups may be used in combination.

  The content of the crosslinkable group in the star polymer compound is preferably 0.1 to 10.0 mmol, more preferably 0.25 to 7.0 mmol, most 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 ²⁰ R ²¹ (M ¹ represents hydrogen, metal ion, ammonium ion, phosphonium ion, and R ²⁰ and R ²¹ each independently represents a hydrogen atom. , alkyl group, alkenyl group, ^{.R 20} and ^{R 21} representing an aryl group may be bonded to form a ^{ring), -. N + R 22} R 23 R 24 X - (R 22 ~R 24 is Each independently represents an alkyl group having 1 to 8 carbon atoms, X- represents a counter anion), a group represented by the following general formula (e) and a group represented by the general formula (f).

In the above formula, n and m each independently represent an integer of 1 to 100, and R ²⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.

  Here, when the star-shaped polymer compound is a star-shaped polymer compound having a polyoxyalkylene chain (for example, the group represented by the general formula (e) or (f)) on the side, Such a star polymer compound is also a polymer compound having the above-described polyoxyalkylene chain in the side chain.

Among these hydrophilic groups, —CONR ²⁰ R ²¹ , a group represented by the general formula (e) and a group represented by the general formula (f) are preferable, and represented by —CONR ²⁰ R ²¹ and the general formula (e). The group represented by the general formula (e) is particularly preferred. Further, among the groups represented by the general formula (e), n is more preferably 1 to 10, and particularly preferably 1 to 4. R ²⁵ 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 of these 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 can 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.

  Examples of the star polymer compound include compounds described in paragraphs [0101] to [0105] of JP-A-2015-123683. However, it is not limited to these.

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

  The mass average molar mass (Mw) of the star polymer compound is preferably from 5,000 to 500,000, more preferably from 10,000 to 250,000, and particularly preferably from 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 can contain other components described below as required.

(1) Low molecular weight hydrophilic compounds
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 the group of polyols, organic sulfates, organic sulfonates, and betaines.

  Specific examples of the organic sulfonate 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, 3- (1-pyridinio) -1-propanesulfonate and the like can be mentioned.

  Since low molecular weight hydrophilic compounds have a small hydrophobic part structure and almost no surface-active action, the dampening solution penetrates into the exposed part (image part) of the image recording layer, thereby improving the hydrophobicity and film strength of the image part. The ink receptivity and printing durability of the image recording layer can be maintained well without being reduced.

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

(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.

  Preferred examples of the phosphonium compound include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butanedi (hexafluorophosphate), 1,7-bis (triphenylphosphonate). Nio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonannaphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compounds include the compounds described in paragraph numbers [0021] to [0037] of JP-A-2008-284858 and paragraph numbers [0030] to [0057] of JP-A-2009-90645. It is done.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component. preferable. Specific examples include the polymers described in paragraph numbers [0089] to [0105] of JP2009-208458A.

  The ammonium group-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110. Those in the range of 100 are particularly preferred. When the said reduced specific viscosity is converted into a mass mean molar mass (Mw), 10,000-150,000 are preferable, 17000-140000 are more preferable, 20000-130000 are especially preferable.

<Measurement method of reduced specific viscosity>
Weigh 3.33 g of 30% polymer solution (1 g as solid content) into a 20 ml volumetric flask and make up with N-methylpyrrolidone. This solution is allowed to stand for 30 minutes in a constant temperature bath at 30 ° C., put in an Ubbelohde reduced viscosity tube (viscosity constant = 0.010 cSt / s), and the time for flowing down at 30 ° C. is measured. The measurement is performed twice with the same sample, and the average value is calculated. Similarly, in the case of a blank (only N-methylpyrrolidone), the reduced specific viscosity (ml / g) is calculated from the following formula.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (trimethylammonio) ethyl methacrylate p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 Mw 45,000) (2) 2- (trimethylammonio) Ethyl methacrylate hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 60,000) (3) 2- (ethyldimethylammonio) ethyl methacrylate p-toluenesulfonate / hexyl methacrylate Copolymer (molar ratio 30/70 Mw 45,000) (4) 2- (trimethylammonio) ethyl methacrylate hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw 60,000) ( 5) 2- (Trimethylammonio) ethyl methacrylate Relate methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw 7 million) (6) 2- (butyldimethylammonio) ethyl methacrylate hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (Molar ratio 25/75 Mw 65,000) (7) 2- (Butyldimethylammonio) ethyl acrylate hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (Molar ratio 20/80 Mw 650,000) ) (8) 2- (butyldimethylammonio) ethyl methacrylate 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 75,000) (9) 2- (Butyldimethylammonio) Methacrylate hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyl oxy propyl methacrylate copolymer (molar ratio 15/80/5 Mw6.5 50,000)
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. Further preferred.

(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 the addition amount described in paragraph [0060] of FIG.

For example, as described in paragraphs [0142] to [0143] of JP-A No. 2008-195018, the image recording layer is prepared by dispersing or dissolving the necessary components in a known solvent to prepare a coating solution. It is formed by coating this on a support by a known method such as bar coater coating and drying. 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.

(Undercoat layer)
The lithographic printing plate precursor is preferably provided with an undercoat layer (sometimes referred to as an intermediate layer) between the image recording layer and the support. 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 monomer having an adsorbing group such as a phenolic hydroxy group, a carboxy group, -PO3H2, -OPO3H2, -CONHSO2-, -SO2NHSO2-, -COCH2COCH3, and a monomer having a hydrophilic group such as a sulfo group And a copolymer with a monomer having a polymerizable crosslinkable group such as a methacryl 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 molar mass of 5000 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.

(Protective layer)
In the planographic printing plate precursor, a protective layer (overcoat layer) is preferably provided on the image recording 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. Specifically, modified polyvinyl alcohol described in JP-A-2005-250216 and JP-A-2006-259137 is preferable.

  The protective layer preferably contains an inorganic stratiform compound such as natural mica and synthetic mica as described in JP-A-2005-119273 in order to enhance oxygen barrier properties.

  It is also preferable that the protective layer contains 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 and the like), 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 polysaccharide is preferably used in the range of 1 to 20% by mass relative to the solid content of the protective layer.

  Further, the protective layer can 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 can contain the sensitizer described in the description of the image recording layer.

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

[Image-like exposure]
Imagewise exposure is performed on the lithographic printing plate precursor for on-machine development described above, and an exposed portion and a non-exposed portion are formed on the lithographic printing plate precursor.

The image-like exposure is preferably performed by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data. The wavelength of the light source is preferably 700 to 1400 nm. As the light source of 700 to 1400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. Image-like exposure can be performed by a conventional method using a CTP (Computer to plate) apparatus (also referred to as a plate setter) or the like.

  FIG. 2 is a conceptual diagram of a CTP system including a CTP device. As shown in FIG. 2, the CTP system 1 includes a RIP device 10, a CTP device 20, and a stocker 30.

  The printing system including the CTP system 1 further includes an information management server (not shown) and a client computer. An order number, JOBID (work identification number), customer information, color plate name, screen type, paper name, paper size, etc. are input to the information management server, and a print instruction is issued. In the client computer, an image, a document, or the like is edited to produce so-called image information. Further, plate information necessary for mounting on the printing press is input to the client computer.

  Image information and version information created by the client computer are input to the RIP device 10. The RIP device 10 converts the image information and the plate information into a raster image. Print information including image information and plate information converted to a raster image is input to the CTP device 20. The CTP apparatus 20 is provided with an exposure mechanism, and imagewise exposure is performed on the planographic printing plate precursor based on the printing information input by the exposure mechanism. An exposed portion and a non-exposed portion are formed on the lithographic printing plate precursor by imagewise exposure by the CTP apparatus 20.

  The version information can be added not only from the client computer but also using the function of the RIP device 10.

  When the image recording layer of the lithographic printing plate precursor is exposed, the infrared absorber is excited from HOMO (Highest Occupied Molecular Orbital) to LUMO (Lowest Unoccupied Molecular Orbital) in the exposed area, Color develops.

The planographic printing plate precursor 2 that has been subjected to image-like exposure is discharged from the CTP apparatus 20. In the discharged lithographic printing plate precursor 2, since the exposed portion is colored and the non-exposed portion is not colored, the color difference ΔE in the L ^* a ^* b ^* color space between the exposed portion and the non-exposed portion is 2 or more. 8 or less.

In the present embodiment, the color difference ΔE can be obtained by the following formula (formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
(In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.)
The L ^* a ^* b ^* color space is a color system for representing the color of an object standardized by the International Commission on Illumination (CIE) and defined by JIS Z8781-4: 2013. In the L ^* a ^* b ^* color space, L ^* indicates lightness, and a ^* b ^* indicates hue and saturation.

Since the color difference ΔE in the L ^* a ^* b ^* color space between the exposed part and the non-exposed part is 2 or more and 8 or less, the exposed part and the non-exposed part can be recognized. The color difference ΔE between the exposed part and the non-exposed part can be measured by, for example, a color difference meter (X-Rite: SpectroEye).

<Imaging Step (Step S2)>
In the imaging step (step S2), the first information composed of the exposure part and the non-exposure part is converted into the first electronic information.

  As shown in FIG. 2, the CTP device 20 includes an imaging unit 40 that images the exposed surface of the discharged lithographic printing plate precursor 2. The imaging unit 40 includes an imaging device, and the imaging device converts light into an electrical signal. A CCD (Charge-Coupled Device) image sensor and a CMOS (Complementary MOS) image sensor can be applied as the imaging device.

  The imaging unit 40 may be a line system in which image sensors are arranged in a row, or an area system in which image sensors are arranged two-dimensionally. As for the line system, a CCD system and a CIS (Contact Image Sensor) system may be used. In the CCD system, the reflected light from the object is reflected using a mirror, collected using a plurality of lenses, and then read. On the other hand, in the CIS method, a mirror is not provided, and reflected light from an object is directly read by a sensor.

  The 1st information which consists of an exposure part and a non-exposure part is demonstrated with reference to FIG.3 and FIG.4. FIG. 3 is a plan view of the planographic printing plate precursor 2 after imagewise exposure. As shown in FIG. 3, when the imagewise exposure is completed, a printing region 3 used for printing in the printing machine is formed on the exposed surface of the planographic printing plate precursor 2. In the present embodiment, a plurality of print areas 3 are formed. The print area 3 includes image information (characters to be printed, drawings, etc.) composed of an exposed portion and a non-exposed portion.

  Further, a non-printing area 4 that is not used by the printing press is formed around the printing area 3 on the exposed surface of the planographic printing plate precursor 2. First information 5 including the exposed portion 5A and the non-exposed portion 5B is formed in the non-printing area 4 (see FIG. 4). The first information 5 includes plate information that is not used for printing. The version information may be expressed by characters that allow a person to recognize the content, or may be expressed by a code that cannot be recognized by the person.

  In the present embodiment, the first information 5 is formed in two places in the non-printing area 4, but it is sufficient that it is formed in at least one place.

  FIG. 4 is a partially enlarged view of the first information 5. In FIG. 4, the first information 5 includes, for example, “A” as a character. The letter “A” is composed of an exposure part 5A and a non-exposure part 5B. Before exposure, the non-printing area 4 of the planographic printing plate precursor 2 is composed of only the non-exposed part 5B. In the non-printing area 4, the CTP device 20 performs imagewise exposure in the form of “A”, whereby the exposed area of the “A” form is colored. A color difference ΔE of 2 or more and 8 or less exists between the exposed portion 5A and the non-exposed portion 5B due to color development, and as a result, the character “A” can be recognized by using the color difference ΔE.

  The first information 5 is imaged by the imaging unit 40 shown in FIG. The first information 5 is converted into the first electronic information 50 by the imaging unit 40. Specifically, the first information 5 is converted into the first electronic information 50 by the imaging element of the imaging unit 40. The first electronic information 50 is also imaging data of the first information 5. The first electronic information 50 is transmitted to the control unit 70 via the first transmission unit 44. The control unit 70 includes a processing unit 72 and a print control unit 74. The control unit 70 controls the entire printing apparatus.

  In the imaging step (step S2), it is preferable that the first information 5 is irradiated with light having a wavelength of 620 nm or more and 750 nm or less, and reflected light of the light is detected by the imaging unit 40. This is because the exposure portion 5A constituting the first information 5 has a peak emission wavelength in the range of 620 nm or more and 750 nm or less, which is near infrared. Light having a wavelength of 620 nm or more and 750 nm or less is reflected by the exposure unit 5A of the first information 5 more than the non-exposure unit 5B, and the imaging unit 40 can easily detect the difference between the exposure unit 5A and the non-exposure unit 5B. This is because noise is reduced.

<Processing Step (Step S3)>
In the processing step (step S3), the first electronic information is converted into second electronic information. As shown in FIG. 2, the first electronic information 50 is input to the processing unit 72 of the control unit 70. The processing unit 72 converts the first electronic information 50 into the second electronic information 52. For example, the processing unit 72 performs binarization processing on the first electronic information 50 and converts the first electronic information 50 into second electronic information 52 that is a binarized image of the first electronic information 50. The binarization process means a process of converting dark and shaded imaging data into two gradations of white and black with a certain threshold as a reference.

  FIG. 5 is a conceptual diagram of the second electronic information 52 obtained by binarizing the first electronic information 50. In the present embodiment, the first electronic information 50 has a density difference of a color difference ΔE between the exposed portion 5A and the non-exposed portion 5B. Therefore, the binarization process is performed with reference to a certain threshold value, and the first electronic information 50 to the second electronic information 52 are converted by converting the exposed portion 5A of the first electronic information 50 into black and the non-exposed portion 5B into black. Is converted to Although the binarization process is illustrated as a method for converting the first electronic information 50 into the second electronic information 52, the present invention is not limited to this.

  In the present embodiment, the first information 5 has been described with respect to the character “A”, but the first electronic information 50 is converted into the second electronic information 52 even when the first information 5 is expressed by a code instead of the character. can do.

  Regarding the setting of the threshold value in the binarization process, it can be directly specified, or can be automatically obtained from a calculation formula or the like.

<Printing process (step S4)>
In the printing step (step S4), the second information is printed on the planographic printing plate precursor based on the second electronic information.

  As shown in FIG. 2, in the printing process, for example, based on the second electronic information 52, a control signal from the print control unit 74 is transmitted via the second transmission unit 46, and the printing unit 60 performs first printing. This is executed by printing the two information on the planographic printing plate precursor 2.

  The first transmission unit 44 and the second transmission unit 46 may be wired or wireless as long as an electrical signal can be transmitted.

  In the present embodiment, the second information includes plate information (order number, JOBID (work identification number), customer information, color plate name, screen type, paper name, paper size, etc.) that can be recognized by a person.

  FIG. 6 is a plan view of the planographic printing plate precursor after the second information is printed. As shown in FIG. 6, the second information 6 is printed on the exposed surface of the planographic printing plate precursor 2. As described above, the second information 6 includes version information composed of characters and the like that can be recognized by a person. Since the second information 6 is printed based on the binarized second electronic information 52, a person can easily recognize the plate information.

  When the lithographic printing plate precursor 2 is developed on the machine, the second information 6 produced by printing is the exposure surface of the lithographic printing plate precursor 2 by at least one of dampening water and printing ink supplied to the printing machine. Removed from. Therefore, the second information 6 can be printed so as to overlap the printing area 3 of the planographic printing plate precursor 2. Further, the second information 6 can be displayed larger than the first information 5 so that a person can easily recognize the version information.

  The ink on the surface of the lithographic printing plate precursor is removed with dampening water, and the ink entering the overcoat layer of the lithographic printing plate precursor is removed together with the overcoat layer. Presumed to have been removed by printing ink.

  When the first information 5 is composed of plate information that can be recognized by a person such as characters, the second electronic information 52 is information obtained by binarizing the first information 5, and the second electronic information 52 is the second information. Information 6 is printed on the planographic printing plate precursor 2. On the other hand, when the first information 5 is not composed of version information that can be recognized by a person such as a code, the second electronic information 52 is converted into version information including character information that can be recognized by a person. The converted plate information is printed on the planographic printing plate precursor 2 as second information 6.

  For example, the printing unit 60 is preferably a printing apparatus to which an ink jet recording method using an ink containing a dye is applied. The ink jet recording method is a method of recording an image by ejecting ink (ink droplets) from a plurality of nozzles formed on a recording head to an object. Among the ink jet recording methods, the drop on demand method is preferable, and among them, the thermal method is preferable.

  The drop-on-demand system means an ink jet recording system that ejects ink (ink droplets) only when necessary as a printing operation. The thermal system means a system in which ink is boiled by instantaneously raising the temperature with a heater and ink droplets are ejected from nozzles by bubbles.

〔ink〕
In the present embodiment, the ink used for printing the plate information is preferably an ink containing a dye as a colorant.

<Solvent>
The solvent constituting the ink preferably contains pure water and an aqueous solvent. As pure water, ion exchange water, distilled water, or the like is preferably used. The aqueous solvent is appropriately used for adjusting the drying of the ink on the lithographic printing plate precursor for on-press development. The ink is preferably contained in the range of 0.1 to 50% by mass. As the aqueous solvent, it is preferable to use one or more of methyl alcohol, ethyl alcohol, isopropyl alcohol, t-butanol, glycerin, propylene glycol, ethylene glycol, polyethylene glycol, propylene glycol monomethyl ether, etc. More preferably, seeds or more are used.

<Dye>
As the dye contained in the ink, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes Is mentioned.

  Of these dyes, azo dyes, metal complex azo dyes, pyrazolone azo dyes, and carbonium dyes are preferable, and pyrazolone azo dyes and carbonium dyes are more preferable.

  As the diphenylmethane dye, for example, auramine is preferable.

  The triphenylmethane dye is preferably at least one selected from the group of diamino dyes, triamino dyes, and oxyfuxone dyes.

  Examples of the diamino dye include Malachite Green, Brilliant Green G, Setoglaucine (Gy), Roduline Blue 6G (IG), Astra Astrazone Blue G (IG), Fast Green FCF, Brilliant Blue FCF, Light Green SF yellowish, Brilliant Milling Green G ( Brilliant Milling Green B), Patent Blue AF, Wool Green S, and Wool Green BS are preferable.

  Examples of the triamino dye include Para Rosaniline, Methyl Violet, Crystal Violet, Victoria Blue B, Soluble Blue, and Acid Violet. (Acid Violet) is preferred.

  Examples of oxyfuxone dyes include Chromoxane Violet RS (IG), Chromoxane Violet R (Gy), Chromoxane Brilliant Violet RE, and Chromoxane Brilliant Violet RE. Preferred are Chromoxane Pure Blue B and Chromoxane Pure Blue BX.

  The xanthene dye is preferably a galein type or a rhodamine type. The galein type is preferably gallein SW or Coerulein S. As the rhodamine system, rhodamine B (Rodamine B), rhodamine SB (Rodamine SB), sulforhodamine B extra (Sulforhadamine B), and chromoxane brilliant red BL (Chromoxane Brilliant Red BL) are preferable.

  The acridine dye is preferably acriflavine, axridine orange NO, or phosphine C.

  The carbonium dye is exemplified as described above, but is not limited thereto.

<Others>
If necessary, additives such as a water-soluble fixing agent, an antifungal agent, a precipitation preventing agent, a pH adjusting agent, an antifoaming agent, and a surfactant can be added to the ink.

[Example 1]
Production of planographic printing plate precursor (1) for on-press development (for Examples 1 to 14)
<Production of support>
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then 0.3 mm The surface of the aluminum plate was grained with three bundle-planted nylon brushes having a bristle diameter and 25 μm median diameter pumice-water suspension (specific gravity 1.1 g / cm ³ ) and washed thoroughly with water. Etching was performed by immersing the aluminum plate in a 25% by mass sodium hydroxide aqueous solution at 45 ° C. for 9 seconds, washing with water, and further immersed in a 20% by mass nitric acid aqueous solution at 60 ° C. for 20 seconds and washing with water. The etching amount of the grained surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions), and the solution temperature was 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. 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 in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Subsequently, in a 0.5% by mass aqueous hydrochloric acid solution (the aluminum aluminum plate contains 0.5% by mass of conditional ions having an electric quantity of 50 C / dm ² at the time of anode), an electrolytic solution having a liquid temperature of 50 ° C., nitric acid An electrochemical surface roughening treatment was performed in the same manner as in the electrolysis, followed by washing with water by spraying.

Next, after providing a 2.5 g / m ² direct current anodic oxide film with a current density of 15 A / dm ² as an electrolytic solution on a 15% by weight sulfuric acid aqueous solution (containing 0.5% by weight of aluminum ions) on an aluminum plate, Washed with water and dried to prepare a support A. When the average pore diameter (surface average pore diameter) in the surface layer of the anodized film was measured by the following method, it was 10 nm.

  That is, for measurement of the pore diameter in the surface layer of the anodized film, an ultra-high resolution SEM (Hitachi S-900) is used, and a deposition process for imparting conductivity is performed at a relatively low acceleration voltage of 12 V. Without, the surface was observed at a magnification of 150,000 times, and 50 pores were randomly extracted to obtain an average value. The standard deviation error was ± 10% or less.

Thereafter, in order to ensure the hydrophilicity of the non-image area, the support A was subjected to a silicate treatment for 10 seconds at 60 ° C. using a 2.5 mass% No. 3 sodium silicate aqueous solution (JIS K1408), and then washed with water. Thus, a support B was produced. The adhesion amount of Si was 10 mg / m ² . The center line average roughness (Ra) of the support was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

<Formation of undercoat layer>
On the support B, an undercoat layer coating solution (1) having the following composition was applied so that the coating amount after drying was 20 mg / m ² to form an undercoat layer.

<Coating liquid for undercoat layer (1)>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

<Formation of image recording layer>
On the undercoat layer, an image recording layer coating solution (1) having the following composition is bar coated and oven dried at 100 ° C. for 60 seconds to form an image recording layer having a coating amount of 1.0 g / m ² after drying. did.

  The image recording layer coating solution (1) was prepared by mixing and stirring the following photosensitive solution and microgel solution immediately before coating.

<Photosensitive solution>
-Binder polymer (1) [the following structure] 0.240 g
-Polymerization initiator (1) [the following structure] 0.245 g
-Cyanine dye (X-1) [the following structure] 0.023 g
・ Borate compound [the following structure] 0.010 g
TPB: Sodium tetraphenylborate
・ Polymerizable monomer 0.192g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Low molecular weight hydrophilic compound 0.062g
Tris (2-hydroxyethyl) isocyanurate Low molecular weight hydrophilic compound (1) [the following structure] 0.050 g
・ Fat Sensitizer 0.055g
Phosphonium compound (1) [the following structure]
・ Fat Sensitizer 0.018g
Benzyl-dimethyl-octylammonium / PF6 salt / Sensitizer 0.035 g
Ammonium group-containing polymer (following structure)
[The following structure, reduced specific viscosity 44 ml / g]
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g
<Microgel solution>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g
Binder polymer (1), cyanine dye (X-1), fluorosurfactant (1), low molecular weight hydrophilic compound (1), phosphonium compound (1), ammonium group-containing polymer and TPB used in the above photosensitive solution The structure of is as follows.

  A method for preparing the microgel (1) used in the microgel solution is shown below.

<Preparation of microgel (1)>
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Takenate D-110N, manufactured by Mitsui Chemicals, Inc.) 10 g, pentaerythritol triacrylate (SR444, manufactured by Nippon Kayaku Co., Ltd.) 3.15 g, and alkylbenzene 0.1 g of sulfonate (Pionin A-41C, manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. 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, and then stirred at room temperature for 30 minutes and then 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 was measured by a light scattering method and found to be 0.2 μm.

<Formation of protective layer>
On the image recording layer, a protective layer coating solution having the following composition was coated with a bar and dried in an oven at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ^2. Lithographic printing plate precursor A for Examples 1-14 was prepared.

<Protective layer coating solution>
Inorganic layered compound dispersion (1) [below] 1.5 g
Polyvinyl alcohol (CKS50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modified,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ 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
・ Polyoxyethylene lauryl ether (Emalex 710,
Surfactant manufactured by Nippon Emulsion Co., Ltd.) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g
A method for preparing the inorganic layered compound dispersion (1) used in the protective layer coating solution is shown below.

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

The lithographic printing plate precursor (1) for on-press development is produced by Fujifilm Corporation's Luxel PLANETSETTER T-6000III equipped with an infrared semiconductor laser, with an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. Exposure was performed under conditions.
Printing was performed on the lithographic printing plate precursor (1) using the ink (1) having the following composition.

<Ink (1)>
Solvent / pure water 80.0wt%
・ Ethyl alcohol 7.5wt%
Colorant / Methyl Violet 2.5wt%
Printing was performed by the following steps.
First, the first information formed by exposure on the planographic printing plate precursor (1) is transferred to a digital camera (A:
It was read by Teledyne DALSA P4-CM-02K10D-00-R, B: Keyence SR-1000 (only two-dimensional barcode reading), and converted to first electronic information. Next, the first electronic information was converted into second electronic information. Finally, using the ink jet device, the second information was printed by ejecting the ink (1) onto the second electronic information by the ink jet device (Yamazaki Sangyo Co., Ltd .: GRAPHICA 5000).

  The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After fountain solution and ink were supplied by the standard automatic printing start method of LITHRONE26 and developed on the machine, printing was performed using Tokishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour. went.

[Example 2]
A lithographic printing plate precursor (2) subjected to printing was produced in the same manner as in Example 1 except that the ink (2) having the following composition was used instead of the ink (1). Polyethylene glycol was added for the purpose of preventing drying of the nozzle surface of the ink jet apparatus.

<Ink (2)>
Solvent / pure water 75.0wt%
・ Ethyl alcohol 17.5wt%
Colorant / Methyl Violet 2.5wt%
Additives ・ Polyethylene glycol (Mw: 200) 5.0wt%
Example 3
A lithographic printing plate precursor (3) on which printing was performed was produced in the same manner as in Example 1 except that the ink (3) having the following composition was used instead of the ink (1).

<Ink (3)>
Solvent / pure water 80.0wt%
・ Glycerin 17.5wt%
Colorant / Methyl Violet 2.5wt%
[Example 4-14]
Lithographic printing plate precursors (4) to (14) on which printing was performed were produced in the same manner as in Example 1 except that the colorant shown in Table 1 was used as the ink (1).

<Evaluation of lithographic printing plate precursor (1) subjected to printing>
(On-press developability)
On-press development of the unexposed portion of the image recording layer is completed on the printing machine, and ink is ejected to produce the second information, and the ink ejected onto the image portion of the lithographic printing plate precursor The number of printing papers required until the paper could not be transferred to the paper was evaluated as on-machine developability. The smaller the number, the better the on-press developability. The results are shown in Table 1.

(Dirt)
The background stain of the planographic printing plate precursor (1) on which the above printing was performed was evaluated. Here, the background stain refers to a stain on the paper surface due to ink ejected to produce the second information and ejected onto a non-image portion of the lithographic printing plate precursor. The ink is oleophilic because the ink remains or some influence is given to the non-image area. The background stain on the 500th print start was evaluated according to the following standards. The evaluation results are shown in Table 1. 5 to 3 are acceptable levels.

5: No dirt is observed 4: Intermediate level between 5 and 3 3: Dirt is slightly recognized 2: Intermediate level between 3 and 1 1: Dirt is clearly recognized (Blank dirt)
The blemishes of the planographic printing plate precursor (1) on which the above printing was performed were evaluated. Here, the “blank stain” refers to a stain due to ink (ink ejected for producing the second information) in the blanket after printing. The blank stain on the 500th sheet from the start of printing was evaluated according to the following standards. The evaluation results are shown in Table 1. 5 to 3 are acceptable levels.

5: No dirt is observed 4: Intermediate level between 5 and 3 3: Dirt is slightly recognized 2: Intermediate level between 3 and 1 1: Dirt is clearly recognized (Leave dirt)
After the on-press development described above, printing was continued and 10,000 sheets were printed. Thereafter, the printing press was stopped and restarted after 1 hour.

  At that time, after restarting the smudges in the extracted characters of the printed matter, the blank smear due to the 100th ink (ink ejected to produce the second information) was evaluated according to the following standards. The evaluation results are shown in Table 1. 5 to 3 are acceptable levels.

5: Stain is not observed at all 4: Intermediate level between 5 and 3 3: Smudge is slightly observed 2: Intermediate level between 3 and 1 1: Stain is clearly recognized On-machine developability, background stain, blanc stain In addition, all of the evaluations of the left stains were performed visually.

  From the results shown in Table 1, when the second information is produced by ejecting ink containing a dye, good results are obtained for the evaluation items of on-machine developability, background stain, bran stain, and neglected stain. It was.

  From the results shown in Table 1, Examples 12 and 13 using xanthene dye and Example 14 using acridine dye are between 58 and 63 sheets in terms of on-press developability evaluation items. In addition, an evaluation of 3 was obtained with respect to the evaluation items of left-stained dirt.

  From the results of Table 1, Example 8 using diphenylmethane dye and Example 9-11 using oxyfuxon dye are between 31 and 36 sheets in terms of on-press developability evaluation items. In addition, an evaluation of 4 was obtained with respect to the evaluation items of the leftover stain.

  From the results of Table 1, Examples 1-7 using triamino dyes are between 21 and 24 sheets in the on-press developability evaluation items, and for the evaluation items of background stains, bran stains and neglected stains A rating of 5 was obtained.

  According to the present invention, it is possible to print the second information (plate information) on the lithographic printing plate precursor for on-press development, and the second information produced with the ink containing the dye is used during on-press development. It can be understood that good results can be obtained with respect to the evaluation items of on-press developability, background stain, bran stain, and neglected stain.

DESCRIPTION OF SYMBOLS 1 CTP system 2 Planographic printing plate precursor 3 Printing area 4 Non-printing area 5 1st information 5A Exposure part 5B Non-exposure part 6 2nd information 10 RIP apparatus 20 CTP apparatus 30 Stocker 40 Imaging part 44 1st transmission part 46 2nd transmission Unit 50 first electronic information 52 second electronic information 60 printing unit 70 control unit 72 processing unit 74 printing control unit

Claims (8)

A printing method for a lithographic printing plate precursor,
A lithographic printing plate precursor including an exposed portion and a non-exposed portion by imagewise exposure, wherein a color difference ΔE in an L ^* a ^* b ^* color space obtained by the following formula between the exposed portion and the non-exposed portion: A step of preparing a lithographic printing plate precursor for on-press development, wherein is 2 or more and 8 or less,
An imaging step of converting first information consisting of the exposed portion and the non-exposed portion into first electronic information;
A process of converting the first electronic information into second electronic information;
A printing step of printing second information on the planographic printing plate precursor based on the second electronic information;
Printing method on lithographic printing plate precursor.
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.   The printing method for a lithographic printing plate precursor according to claim 1, wherein the printing in the printing step is performed by an ink jet recording method using an ink containing a dye.   The printing method on a lithographic printing plate precursor as claimed in claim 2, wherein the dye is a carbonium dye.   The printing method for a lithographic printing plate precursor according to claim 3, wherein the carbonium dye is at least one selected from the group of diphenylmethane dye, triphenylmethane dye, xanthene dye, and acridine dye.   The printing method for a lithographic printing plate precursor according to claim 4, wherein the carbonium dye is a triphenylmethane dye.   The method for printing on a lithographic printing plate precursor according to claim 5, wherein the triphenylmethane dye is a triamino dye.   The lithographic printing plate precursor according to any one of claims 1 to 6, wherein in the imaging step, the first information is irradiated with light having a wavelength of 620 nm or more and 750 nm or less to detect reflected light of the light. Printing method. A printing device for a lithographic printing plate precursor,
A color difference ΔE in an L ^* a ^* b ^* color space that is obtained by the following formula between the exposed part and the non-exposed part is 2 or more and 8 or less, including an exposed part and an unexposed part by imagewise exposure. An imaging unit for converting first information consisting of the exposed portion and the non-exposed portion of the lithographic printing plate precursor for on-machine development into first electronic information;
A processing unit for converting the first electronic information into second electronic information;
A printing unit that prints second information on the planographic printing plate precursor based on the second electronic information;
A first transmission unit for transmitting the first electronic information from the imaging unit to the processing unit;
A second transmission unit for transmitting second electronic information to the printing unit;
A printing device for lithographic printing plate precursors.
(Formula): ΔE = ((L2 ^* −L1 ^* ) ² + (a2 ^* −a1 ^* ) ² + (b1 ^* −b2 ^* ) ² ) ^1/2
In the formula, L1 ^* , a1 ^* , and b1 ^* represent values of the exposed portion, and L2 ^* , a2 ^* , and b2 ^* represent values of the non-exposed portion.

Images