JP2007079536A - Plate-making method of lithographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plate-making method of a lithographic printing plate precursor capable of writing with a blue laser and capable of making a lithographic printing plate in which high quality dots of an FM screen are stably obtained. <P>SOLUTION: The plate-making method of a lithographic printing plate precursor comprises exposing a lithographic printing plate precursor having on a support a photosensitive layer formed of a photosensitive composition comprising: a sensitizing dye capable of absorbing light at 360-450 nm; a polymerization initiator; a polymerizable compound; and a binder polymer by utilizing an inner drum exposure apparatus having mounted thereon a light source having an oscillation wavelength in a range of 360-450 nm, wherein the exposure apparatus produces a light beam spot shape of a light beam in which the light beam is divided into an ordinary ray and an extraordinary ray parallel to each other at an equivalent light quantity, and two beam spots of the ordinary and extraordinary ray are adjacently arrayed in a sub-scanning direction so as to partially overlap with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plate making method of a lithographic printing plate precursor, and more particularly to a plate making method of a lithographic printing plate precursor suitable for high-definition AM screen printing or FM screen printing having a screen line number of 200 lines or more.

Conventionally, a lithographic printing plate has a structure in which a photosensitive resin layer is provided on a support having a hydrophilic surface. As a plate-making method, usually, surface exposure (mask exposure) is performed through a lithographic film. The desired printing plate was obtained by removing the non-image area with a developer. However, computer-to-plate that directly exposes the plate surface without using a lith film by scanning the plate surface according to digitized image information with highly directional light such as laser light by recent digitization technology. (CTP) technology has been developed and photosensitive lithographic printing plates adapted to this have been developed.
Examples of the photosensitive lithographic printing plate precursor suitable for exposure with the laser beam include a photosensitive lithographic printing plate using a polymerizable photosensitive layer. By selecting a photopolymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system), the polymerizable photosensitive layer can be easily increased in sensitivity as compared with other conventional photosensitive layers.

  As the laser light source, a 405 nm or 830 nm semiconductor laser, an FD-YAG laser, or the like is used. In recent years, CTP systems equipped with a 405 nm blue-violet semiconductor laser have become widespread from the viewpoints of system cost and handleability.

However, when the photosensitive lithographic printing plate precursor as described above is drawn with the 405 nm blue-violet laser light as described above, the edge of the image depends on the shape of the energy distribution of the laser light, and the polymerization is not caused by insufficient exposure. A sufficient area is formed. For this reason, the sharpness of the image edge is impaired, leading to a decrease in resolution. In addition, such poorly polymerized image edges have poor removal due to the alkali concentration of the developer and the state of the developing brush in the development processing step, and the in-plane variation in the halftone dot area of the plate making plate is increased. It was.
Furthermore, since such a printing plate uses a support having irregularities formed on the surface by electrolytic treatment or brushing to ensure hydrophilicity as a support, it is further caused by scattering of reflected light during laser exposure. Image quality and sharpness are impaired, and the reproducibility of the shadow portion is greatly reduced.

  On the other hand, in recent years, the demand for high-definition AM screen printing and FM screen printing has increased in the CTP technology, and the resolution of the planographic printing plate precursor has become an important performance.

  The FM (Frequency Moduration) screen is a system in which minute dots of about 20 microns are randomly arranged regardless of the screen angle and the number of lines, and the density gradation is expressed by the dot density per unit area. Features of this FM screen printed matter include no interference moiré or rosette pattern, no tone jump in the halftone area near 50%, and halftone dots are small. There are advantages such as the colors appearing vivid.

  On the other hand, an AM (Amplitude Moduration) screen is one in which halftone dots are regularly arranged at a certain angle, and density gradation is expressed by the size of halftone dots per unit area. The number of AM screen lines in Japan is 175 lines per inch. On the other hand, what uses a screen line number of 200 lines or more is generally called high definition.

  Features of high-definition printed materials include a reduction in moire and rosetta patterns, an improvement in image texture, a sense of existence, and an improvement in reproducibility of details.

  However, in the plate making method in which the above-described photosensitive lithographic printing plate precursor is drawn with a laser beam of 405 nm, the reproducibility of the shadow portion is lowered and it is difficult to provide a printing plate suitable for FM screen and high-definition AM screen printing. It was.

  Patent Document 1 discloses a photosensitive lithographic printing plate in which an intermediate layer containing a polymer compound having a structural unit having a sulfonic acid group in the side chain is provided on a support, and a polymerizable photosensitive layer is provided thereon. Although it is disclosed, it is not yet sufficient as a plate material suitable for high-definition AM screen printing or FM screen printing. In particular, the unevenness of the flat screen on the FM screen is severe and it is difficult to use the FM screen. there were.

Further, Patent Document 2 discloses an inner drum that is widely used as an exposure apparatus and that conducts scanning exposure processing by introducing a light beam such as a laser beam onto the photosensitive surface of a lithographic printing plate precursor disposed on the inner peripheral surface of a cylindrical drum. An exposure apparatus (an inner surface scanning type light beam scanning exposure apparatus) is disclosed. In such an inner drum exposure apparatus, since the light emitted from the laser light source in the single transverse mode is formed on the surface to be scanned to form an image, the shape of the beam spot has a Gaussian distribution. ing. When recording a pixel by exposing with a Gaussian beam spot, the half-width of the beam spot and the pixel size are designed to be approximately the same size or larger so that there is no gap between the scanning lines. . For this reason, an image obtained by recording an FM screen with a long circumference of the recording pixels is likely to have density fluctuations and area fluctuations due to fluctuations in optical power and development conditions such as brush pressure or developer temperature and pH of an automatic processor. Become. That is, the conventional inner drum exposure apparatus has a problem that it is difficult to use the FM screen.
JP 2003-43703 A JP-A-10-133132

  An object of the present invention is to provide a plate making method of a lithographic printing plate precursor capable of making a lithographic printing plate capable of writing with a blue laser and stably obtaining high-quality halftone dots of an FM screen. To do.

  As a result of intensive studies to achieve the above-mentioned problems, the inventor made the photosensitive composition for forming the photosensitive layer of the lithographic printing plate precursor a specific composition, and changed the light beam into an ordinary ray and an extraordinary ray. The above object is achieved by performing exposure with an exposure apparatus that generates a beam spot shape that is split in parallel with equal light quantity and adjacent to each other so that the two beam spots partially overlap in the sub-scanning direction. The present invention has been found.

That is, the present invention is as follows.
1. In the plate making method of exposing a lithographic printing plate precursor having at least a photosensitive layer on a support using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm,
The photosensitive layer comprises a photosensitive composition containing a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound, and a binder polymer,
In the inner drum exposure apparatus, the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beam spots partially overlap. Adjacent to each other in the sub-scanning direction,
A method for making a lithographic printing plate precursor, comprising: placing the lithographic printing plate precursor on the inner drum exposure device; and performing image recording by exposing the light beam spot shape.

2. 2. The plate making method of a lithographic printing plate precursor as described in 1, wherein image recording is performed using an FM screen during the exposure.
3. 3. The plate making method of a lithographic printing plate precursor as described in 1 or 2, wherein a wet or dry development treatment is performed after the image recording.
4). 4. The plate making method of a lithographic printing plate precursor as described in 3, wherein wet development such as alkali development or water development is performed during the development treatment.
5. The plate making method of a lithographic printing plate precursor as described in any one of 1 to 4, wherein the polymerization initiator is a hexaarylbiimidazole compound.
6). The lithographic printing plate precursor as described in any one of 1 to 5, wherein the lithographic printing plate precursor has a protective layer on a photosensitive layer.

7). After exposing a lithographic printing plate precursor having at least a photosensitive layer on a support using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm, an automatic processor equipped with a rubbing member In the plate making method of a lithographic printing plate precursor, the photosensitive layer in the non-exposed area is removed by rubbing the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10.
The photosensitive layer comprises a photosensitive composition containing a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound, and a hydrophobic binder polymer,
In the inner drum exposure apparatus, the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beam spots partially overlap. Adjacent to each other in the sub-scanning direction,
A method for making a lithographic printing plate precursor, comprising: placing the lithographic printing plate precursor on the inner drum exposure device; and performing image recording by exposing the light beam spot shape.

8). 8. The plate making method of a lithographic printing plate precursor as described in 7, wherein image recording is performed using an FM screen during the exposure.
9. The plate making method of a lithographic printing plate precursor as described in 7, wherein the lithographic printing plate precursor has a protective layer on the photosensitive layer.
10. The plate making method of a lithographic printing plate precursor as described in 7, wherein the hydrophobic binder polymer has an acid value of 0.3 meq / g or less.
11. 8. The hydrophobic binder polymer according to 7, wherein the hydrophobic binder polymer is at least one selected from a (meth) acrylic copolymer having a crosslinkable group in a side chain and a polyurethane resin having a crosslinkable group in a side chain. Plate making method of lithographic printing plate precursor.
12 The plate making method of a lithographic printing plate precursor as described in 7, wherein the polymerization initiator is a hexaarylbiimidazole compound.

13. The plate making method of a lithographic printing plate precursor as described in 7, wherein a part or all of the photosensitive layer constituting component is encapsulated in a microcapsule.
14 The plate making method of a lithographic printing plate precursor as described in 7, wherein the rubbing member is at least two rotating brush rolls.
15. The plate making method of a lithographic printing plate precursor as described in 7, wherein the developer has a pH of 3 to 8.

The effect | action of this invention is estimated as follows.
In the plate making method of the lithographic printing plate precursor according to the present invention, the light beam to be exposed is divided into an ordinary ray and an extraordinary ray in parallel with equal amounts of light, and the light beams are arranged adjacently in the sub-scanning direction so as to partially overlap. Is not a Gaussian distribution inherently, but more rectangular. An image exposed with a rectangular beam is presumed to be less susceptible to fluctuations in exposure conditions and development conditions, and a lithographic plate having an exposure apparatus capable of such an exposure operation and a photosensitive layer formed of a specific photosensitive composition By combining with the printing plate precursor, it is considered that a high-quality halftone dot can be stably obtained regardless of various development conditions.

  According to the present invention, a lithographic printing plate precursor having a photosensitive layer that can be written by a laser of a light source having an oscillation wavelength in the range of 360 nm to 450 nm can be stably high-definition even if an FM screen image is drawn. A plate making method of a lithographic printing plate precursor for obtaining an image can be provided.

Hereinafter, the plate making method of the lithographic printing plate precursor according to the invention will be described in detail.
In the plate making method of the lithographic printing plate precursor according to the present invention, a lithographic printing plate precursor having at least a photosensitive layer is exposed on a support using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm. In the plate making method, the photosensitive layer is formed of a photosensitive composition containing a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound, and a binder polymer. The light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with equal light amount, and the two beam spots are adjacent to each other so as to partially overlap each other in the sub-scanning direction. After the lithographic printing plate precursor is placed on an inner drum exposure device, image recording is performed by exposure of the light beam spot shape. It is characterized in.
First, the lithographic printing plate precursor used in the plate making method of the present invention will be described in detail.

<Lithographic printing plate precursor>
The lithographic printing plate precursor used in the present invention was formed on a support by a photosensitive composition containing a sensitizing dye that absorbs light of 360 to 450 nm, a polymerization initiator, a polymerizable compound, and a binder polymer. It has a photosensitive layer.
Each of these members constituting the planographic printing plate precursor will be described.

(Photosensitive layer)
The photosensitive layer of the lithographic printing plate precursor according to the invention includes, as essential components, a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound (hereinafter also referred to as “addition polymerizable compound”), and It is a polymerizable negative photosensitive layer formed of a photosensitive composition containing a binder polymer and further containing a colorant and other optional components as required.

  Since the polymerizable negative photosensitive layer in the present invention is sensitive to light of 360 nm to 450 nm, it can be exposed to a blue laser useful for CTP. Such a sensitizing dye that absorbs light of 360 nm to 450 nm is in an electronically excited state with high sensitivity to blue laser irradiation (exposure), and the electron transfer, energy transfer, and the like related to the electronically excited state are present in the photosensitive layer. It acts on the coexisting polymerization initiator to cause a chemical change in the polymerization initiator to generate radicals. Then, the polymerizable compound causes a polymerization reaction by the generated radical, and the exposed portion is cured to become an image portion.

  In the lithographic printing plate precursor according to the invention, an intermediate layer (undercoat layer) may be provided for the purpose of improving the adhesion and stain resistance between the photosensitive layer and the support. Further, a protective layer (also referred to as an overcoat layer) may be further provided on the photosensitive layer in order to perform exposure in the air. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer, and enables exposure in the atmosphere. To do.

In the lithographic printing plate precursor according to the invention, the photosensitive layer contains a sensitizing dye that absorbs light of 360 nm to 450 nm so that the plate is directly drawn with blue laser light having an oscillation wavelength in the range of 360 nm to 450 nm. It is particularly suitable and can exhibit high image forming properties as compared with conventional lithographic printing plate precursors.
Below, each component which comprises the photosensitive composition which forms the photosensitive layer of the lithographic printing plate precursor concerning this invention is demonstrated.

[Sensitizing dye absorbing light of 360 nm to 450 nm]
The sensitizing dye that absorbs light of 360 nm to 450 nm used in the photosensitive composition used in the present invention preferably has an absorption maximum in the wavelength range of 360 nm to 450 nm. Examples of such a sensitizing dye include merocyanine dyes represented by the following general formula (II), benzopyrans and coumarins represented by the following general formula (III), and fragrances represented by the following general formula (IV). And anthracenes represented by the following general formula (V).

(In the formula, A represents an S atom or NR ₆ , R ₆ represents a monovalent non-metallic atomic group, Y represents a basic nucleus of the dye in cooperation with the adjacent A and the adjacent carbon atom. metallic atomic group, X1, X ₂ each independently represents a monovalent non-metallic atomic group, X _1, X ₂ may be bonded to form an acidic nucleus of the dye together.)

(In the formula, = Z represents an oxo group, a thioxo group, an imino group or an alkylidene group represented by the partial structural formula (I ′), and X ₁ and X ₂ have the same meaning as in the general formula (II); R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.)

(In the formula, Ar ₃ represents an aromatic group or a heteroaromatic group which may have a substituent, and R ₁₃
Represents a monovalent nonmetallic atomic group. R ₁₃ is more preferably an aromatic group or a heteroaromatic group, and Ar ₃ and R ₁₃ may be bonded to each other to form a ring. )

(In the formula, X ₃ , X ₄ and R _{14 to} R ₂₁ each independently represents a monovalent nonmetallic atomic group, and more preferable X ₃ and X ₄ are electron donating groups having a Hammett's substituent constant being negative. .)

In the general formulas (II) to (V), preferred examples of the monovalent nonmetallic atomic group represented by X ₁ to X ₄ and R ₆ to R ₂₁ include a hydrogen atom, an alkyl group (for example, a methyl group, Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group , S-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group, chloromethyl group , Bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, methoxyethoxyethyl Allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonyl Methyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl-N- (sulfofe Carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group, N-methyl -N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobutyl group, tolylphos Phonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatooxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, Cinnamyl group, allyl group, 1-propenylmethyl Group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc.), aryl group (for example, phenyl group, biphenyl group, naphthyl group) , Tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group , Methylthiophenyl group, phenylthiophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarba Moylphenyl group, phenyl group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), heteroaryl group (for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene) , Xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, indazole, purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, cinolin, pteridine, Carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenazazine, phenoxazine, furazane, phenoxazine, etc.), al Nyl group (for example, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group, etc.), alkynyl group (for example, ethynyl group, 1-propynyl group, 1-butynyl group, Trimethylsilylethynyl group, etc.), halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyl group Oxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarba Ileoxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′- Alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N -Arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N -Arylureido group, N'-aryl-N-alkylureido group, N'-aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-di Reel-N-arylureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, acyl group, Carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-ary Rucarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkyl Rusuruhoniru group, an arylsulfonyl group, a sulfo group (-SO ₃ H) and its conjugated base group (hereinafter referred to as sulfonato group), alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group, N- alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group (—PO ₃ H ₂ ) and its conjugated base group (hereinafter referred to as phosphonato group), a dialkyl phosphono group (-PO ₃ (alkyl) _2), Zia Ruhosufono group _{(-PO 3 (aryl) 2)} , alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )), monoalkyl phosphono group (-PO ₃ H (alkyl)) and its conjugated base group (hereinafter , Alkyl phosphonate group), monoaryl phosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as aryl phosphonate group), phosphonooxy group (—OPO ₃ H ₂ ) And its conjugate base group (hereinafter referred to as phosphonatooxy group), dialkyl phosphonooxy group (—OPO ₃ (alkyl) ₂ ), diaryl phosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylaryl phosphono oxy group (-OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (-OPO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphite Onookishi group (-OPO ₃ H (aryl)) and its conjugated base group (hereinafter referred to as aryl phosphite Hona preparative group), a cyano group, a nitro group, etc., and among the above substituents, a hydrogen atom, an alkyl Particularly preferred are groups, aryl groups, halogen atoms, alkoxy groups and acyl groups.

  Examples of the basic nucleus of the dye formed in cooperation with the adjacent A and the adjacent carbon atom in the general formula (II) include 5-, 6-, and 7-membered nitrogen-containing or sulfur-containing heterocyclic rings. A 5- or 6-membered heterocyclic ring is preferable.

  Examples of nitrogen-containing heterocycles include, for example, the basic nucleus in merocyanine dyes described in LGBrooker et al., J. Am. Chem. Soc., 73, 5326-5358 (1951). Any of those known to be used can be suitably used. Specific examples include thiazoles (for example, thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4,5- Di (p-methoxyphenylthiazole), 4- (2-thienyl) thiazole, etc.), benzothiazoles (eg, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7- Chlorobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzo Thiazole, 6-methoxybenzothia Sol, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, 5- Hydroxybenzothiazole, 6-hydroxybenzothiazole, 6-dimethylaminobenzothiazole, 5-ethoxycarbonylbenzothiazole, etc.), naphthothiazoles (for example, naphtho [1,2] thiazole, naphtho [2,1] thiazole, 5- Methoxynaphtho [2,1] thiazole, 5-ethoxynaphtho [2,1] thiazole, 8-methoxynaphtho [1,2] thiazole, 7-methoxynaphtho [1,2] thiazole, etc.), thianaphtheno-7 ′, 6 ', 4,5-thiazoles (eg 4'-methoxy Sithianaphtheno-7 ′, 6 ′, 4,5-thiazole, etc.), oxazoles (for example, 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4, 5-dimethyloxazole, 5-phenyloxazole, etc.), benzoxazoles (benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole 4,6-dimethylbenzoxazole, 6-methoxybenzoxazole, 5-methoxybenzoxazole, 4-ethoxybenzoxazole, 5-chlorobenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6- Droxybenzoxazole etc.), naphthoxazoles (eg naphtho [1,2] oxazole, naphtho [2,1] oxazole etc.), selenazoles (eg 4-methylselenazole, 4-phenylselenazole etc.), Benzoselenazoles (eg, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), naphthoselenazoles (eg, naphtho [1, 2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), 2-quinolines (eg quinoline, 3-methylquinoline, 5-methylquinoline, 7-methyl) Quinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloro Quinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), 4-quinolines (eg, quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline, etc.), 1-isoquinolines (eg, isoquinoline, 3,4-dihydroisoquinoline, etc.), 3-isoquinolines (eg, isoquinoline, etc.), benzimidazoles (eg, 1,3-diethylbenzimidazole, 1-ethyl-3- Phenylbenzimidazole, etc.), 3,3-dialkylindolenines (eg 3,3-dimethylindolenine, 3,3,5, -trimethylindolenine, 3,3,7, -trimethylindolenine, etc.), 2 -Pyridines (eg, pyridine, 5-methylpyridine, etc.), 4-pyridine (eg, pyridine, etc.), etc. Rukoto can.

Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759.
Specific examples include benzodithiols (eg, benzodithiol, 5-t-butylbenzodithiol, 5-methylbenzodithiol, etc.), naphthodithiols (eg, naphtho [1,2] dithiol, naphtho [2,1] Dithiols, etc.), dithiols (for example, 4,5-dimethyldithiols, 4-phenyldithiols, 4-methoxycarbonyldithiols, 4,5-dimethoxycarbonylbenzodithiols, 4,5-ditrifluoromethyldithiols, 4 , 5-dicyanodithiol, 4-methoxycarbonylmethyldithiol, 4-carboxymethyldithiol, and the like.

  As mentioned above, for the sake of convenience, the description used in the description of the heterocyclic ring has conventionally used the name of the heterocyclic mother skeleton, but when forming the basic skeleton partial structure of the sensitizing dye, for example, in the case of the benzothiazole skeleton It is introduced in the form of an alkylidene type substituent with one degree of unsaturation, such as a 3-substituted-2 (3H) -benzothiazolidene group.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (I).

(In the general formula (I), A represents an aromatic ring group or a heterocyclic group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be good.)

General formula (I) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently
Monovalent non-metal atomic group, preferably substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted Represents an alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, and a halogen atom.

Preferable examples of R ₁ , R ₂ and R ₃ will be specifically described. Examples of preferable alkyl groups include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, s-butyl, Examples thereof include a t-butyl group, an isopentyl group, a neopentyl group, a 1-methylbutyl group, an isohexyl group, a 2-ethylhexyl group, a 2-methylhexyl group, a cyclohexyl group, a cyclopentyl group, and a 2-norbornyl group. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

As the substituent of the substituted alkyl group, a monovalent nonmetallic atomic group excluding hydrogen is used, and preferred examples include halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups, alkoxy groups, Aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, Ruthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N'-diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-aryl Ureido group, N ′, N′-dialkyl-N-alkylureido group, N ′, N′-dialkyl-N-arylureido group, N′-aryl-N-alkylureido group, N′-aryl-N-aryl Ureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′- Alkyl-N'-aryl-N-ary Ureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N- Aryl-N-aryloxycarbonylamino group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group (hereinafter, sulfonate group) Called) Alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N- Alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N -Alkyl-N-arylsulfamoyl groups, phosphono groups (-PO ₃ H ₂ ) and their conjugate base groups (hereinafter referred to as phosphonate groups), dialkyl phosphono groups (-PO ₃ (alkyl) ₂ ), diaryl phosphines phono group _{(-PO 3 (aryl) 2)} , alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )), monoalkyl phosphono group -PO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphono group (-PO ₃ H (aryl)) and its conjugated base group (hereinafter, aryl phosphonophenyl group ), Phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonatoxy group), dialkyl phosphonooxy group (—OPO ₃ (alkyl) ₂ ), diaryl phosphonooxy Group (—OPO ₃ (aryl) ₂ ), alkylaryl phosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group ( Hereinafter, it is referred to as an alkylphosphonatooxy group), a monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as an arylphosphonatooxy group), a cyano group, A tro group, an aryl group, a heteroaryl group, an alkenyl group, and an alkynyl group.

  Specific examples of the alkyl group in these substituents include the above-described alkyl groups, and specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, a mesityl group, and a cumenyl group. , Chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylamino Phenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, Examples thereof include a cyanophenyl group, a sulfophenyl group, a sulfonatophenyl group, a phosphonophenyl group, and a phosphonatophenyl group.

As the preferred heteroaryl group as R ₁ , R ₂ and R ₃ , a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used, and examples of particularly preferred heteroaryl groups are as follows. Is, for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indolizine, indazole, indazole, Purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenalazine, phenoxazine, flaza And phenoxazine and the like, and these may be further benzo-fused or may have a substituent.

Examples of preferable alkenyl groups as R ₁ , R ₂ and R ₃ include vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group and the like, and alkynyl Examples of the group include ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group and the like. G1 in the acyl group (G1CO-) is hydrogen,
In addition, the above alkyl groups and aryl groups can be exemplified. Of these substituents, halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N— Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N -Arylsulfamoyl groups, N-alkyl-N-aryls Famoyl group, phosphono group, phosphonate group, dialkyl phosphono group, diaryl phosphono group, monoalkyl phosphono group, alkyl phosphonate group, monoaryl phosphono group, aryl phosphonate group, phosphonooxy group, phosphonatooxy group , Aryl group and alkenyl group.

  On the other hand, examples of the alkylene group in the substituted alkyl group include divalent organic residues obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Can include linear alkylene groups having 1 to 12 carbon atoms, branched chains having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferable substituted alkyl groups as R ₁ , R ₂ and R ₃ obtained by combining the substituent with an alkylene group include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxy Methyl group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N -Cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl Group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group,
N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfuric group Famoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group, N-methyl-
N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobutyl group, tolylphosphono Hexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatooxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, cinnamyl Group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, and the like.

Specific examples of preferred aryl groups as R ₁ , R ₂ and R ₃ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group and a naphthyl group are more preferable. .

Specific examples of preferred substituted aryl groups as R ₁ , R ₂ and R ₃ include those having a monovalent non-metallic atomic group excluding hydrogen as a substituent on the ring-forming carbon atom of the aryl group described above. . Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include a biphenyl group, a tolyl group, a xylyl group, a mesityl group, a cumenyl group, a chlorophenyl group, a bromophenyl group, a fluorophenyl group, a chloromethylphenyl group, and a trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenyl group, N-methylbenzoylaminophenyl group, carboxy Eniru group, methoxycarbonylphenyl group, allyloxycarbonyl phenyl group, chlorophenoxy carbonyl phenyl group, carbamoyl phenyl group, N-
Methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group, N-methyl-N-sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoyl Phenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phos Phonophenyl group, Phosphonatophenyl group, Diethylphosphonophenyl group, Diphenylphosphonophenyl group, Methylphosphonophenyl group, Methylphosphonatophenyl group, Tolylphosphonophenyl group, Tolylphosphonatophenyl group, Allyl group, 1- Propenylmethyl group, 2- A butenyl group, 2-methylallylphenyl group, 2-methylpropenylphenyl group, 2-propynylphenyl group, 2-butynylphenyl group, 3-butynylphenyl group and the like can be mentioned.

Next, A in the general formula (I) will be described. A represents an aromatic ring group or a heterocyclic group which may have a substituent, and specific examples of the aromatic ring group or the heterocyclic group which may have a substituent include those in the general formula (I) Examples thereof are the same as those described for R ₁ , R ₂ and R ₃ .

  The sensitizing dye represented by the general formula (I) is a condensation of an acidic nucleus as shown above or an acidic nucleus having an active methylene group with a substituted or unsubstituted aromatic ring or heterocyclic ring. Although obtained by reaction, these can be synthesized with reference to JP-B-59-28329.

  Preferred specific examples (D1) to (D41) of the compound represented by formula (I) are shown below. In addition, an isomer with a double bond connecting an acidic nucleus and a basic nucleus is not limited to either isomer.

  The sensitizing dye that absorbs light of 360 nm to 450 nm is preferably used in the range of 1.0 to 10.0% by mass in the total components of the photosensitive composition. More preferably, it is the range of 1.5-5.0 mass%.

(Polymerization initiator)
The polymerization initiator used in the present invention is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by light or thermal energy. As such a radical generator, a known polymerization initiator or a compound having a bond having a small bond dissociation energy can be appropriately selected and used.
For example, when light near 400 nm is used as a light source, benzyl, benzoyl ether, Michler's ketone, anthraquinone, thioxanthone, acridine, phenazine, benzophenone, etc. are widely used.

In addition, various photopolymerization initiators have also been proposed when a light beam of 400 nm or more is used as a light source. For example, certain photoreductive dyes described in US Pat. No. 2,850,445 are described. For example, rose bengal, eosin, erythrosine, etc., or a combination of a dye and a photopolymerization initiator, for example, a complex initiation system of a dye and an amine (Japanese Patent Publication No. 44-2018)
9), a combination system of hexaarylbiimidazole, a radical generator and a dye (Japanese Patent Publication No. 45-37377), a system of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (Japanese Patent Publication No. 47-2528, JP-A-54-155292, cyclic cis-α-dicarbonyl compound and dye system (JP-A 48-84183), cyclic triazine and merocyanine dye system (JP-A 54-151024) ) Systems of 3-ketocoumarin and activator (JP-A 52-112681, JP-A 58-15503), biimidazole, styrene derivative, thiol system (JP-A 59-140203), Organic peroxide and dye system (Japanese Patent Laid-Open Nos. 59-1504, 59-140203, 59-1)
89340, Japanese Patent Laid-Open No. 62-174203, Japanese Patent Publication No. 62-1641, US Pat. No. 4,766,055), a system of a dye and an active halogen compound (Japanese Patent Laid-Open No. 63-1781)
No. 05, JP-A-63-258903, JP-A-2-63054, etc.), dye and borate compound systems (JP-A-62-143044, JP-A-62-150242, JP-A-64-164)
No. 13140, JP-A 64-13141, JP-A 64-13142, JP-A 64-13
143, JP 64-13144, JP 64-17048, JP 1-222900
3, JP-A-1-298348, JP-A-1-138204, etc.), a system comprising a dye having a rhodanine ring and a radical generator (JP-A-2-17943, JP-A-2-244050) Can be mentioned.

  Examples of the compounds that generate radicals include organic halogen compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oximes. Examples thereof include ester compounds and onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. The compound as described in Hutt, "Journal of Heterocyclic Chemistry", 1 (No. 3) (1970) is mentioned. Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

  More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring, and oxadiazole derivatives in which the oxadiazole ring is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis ( Trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris ( Tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) Etc. -s- triazine and the following compounds.

Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′
-(Methylthio) phenyl) -2-morpholino-1-propanone, acetophenone derivatives such as 1,1,1-trichloromethyl- (p-butylphenyl) ketone, thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2- Thioxanthone derivatives such as chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, etc. Can be mentioned.

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

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) phenyl) titanium, JP-A-1-304453, Examples thereof include iron-arene complexes described in JP-A-1-152109.

  Examples of the hexaarylbiimidazole compound (triaryl-imidazole dimer compound) include, for example, Japanese Patent Publication No. 6-29285, US Pat. Nos. 3,479,185, 4,311,783, Various compounds described in the specification of No. 4,622,286 and the like, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl)) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5 '-Tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'- Dichlorophenyl) -4,4 ', 5 5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4 , 4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  The process for the preparation of hexaarylbisimidazoles is described in DE 1,470,154 and their use in photopolymerizable compositions is described in EP 24,629. 107,792, U.S. Pat. No. 4,410,621, European Patent 215,453 and German Patent 3,211,312.

  Examples of the organoboron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. No. 131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, etc. Organoborates described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes, JP-A-6-175554 No. 6, JP-A-6-17555 Organoboron iodonium complexes described in JP-A-9-188710, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, Examples thereof include organoboron transition metal coordination complexes such as Kaihei 7-306527 and JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A. Specific examples include compounds represented by the following structural formula.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt described in J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. 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 arsonium salts.

In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
The onium salts preferably used in the present invention are represented by the following general formulas (RI-I) to (RI-II).
An onium salt represented by I).

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  The polymerization initiator is not limited to the above, but an organic halogen compound, a metallocene compound, and a hexaarylbiimidazole compound are more preferable from the viewpoints of reactivity and stability.

  These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto. These polymerization initiators are preferably from 0.1 to 50% by mass, more preferably from 0.5 to 30% by mass, particularly preferably from 0.8 to 20% by mass, based on the total solid content constituting the photosensitive layer. Can be added.

[Polymerizable compound]
The polymerizable compound contained in the photosensitive composition is an addition polymerizable compound having an ethylenically unsaturated double bond, and is a compound having at least one, preferably two or more ethylenically unsaturated double bonds. You can select any of these. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof and copolymers thereof.
Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. These include esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds, and the like. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or 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 Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. 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.

Specific examples of the ester monomer of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, isocyania Examples include nouric acid ethylene oxide (EO) -modified triacrylate and polyester acrylate oligomer.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- 3-methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.
Furthermore, the mixture of the above-mentioned ester monomer can be mention | raise | lifted.

  Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (A) to a polyisocyanate compound having two or more isocyanate groups Etc.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (A)
(However, R ₄ and R ₅ represent H or CH _3. )

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-A No. 62-39417 and JP-B No. 62-39418 are also suitable. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association Vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers,
Can be used.

Specifically, NK oligo U-4HA, U-4H, U-6HA, U-108A, U-108
4A, U-200AX, U-122A, U-340A, U-324A, UA-100 (above,
Shin-Nakamura Chemical Co., Ltd.), UA-306H, AI-600, UA-101T, UA-101I, UA-306T, UA-306I (above, manufactured by Kyoeisha Yushi), Art Resin UN-9200A
, UN-3320HA, UN-3320HB, UN-3320HC, SH-380G, SH-
500, SH-9832 (manufactured by Negami Kogyo Co., Ltd.) and the like.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. Further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

  The polymerizable compound is preferably used in the range of 5 to 90% by mass, more preferably 10 to 80% by mass, and still more preferably 25 to 75% by mass with respect to the total solid content of the photosensitive layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer composition and coating method such as undercoating and overcoating are also considered.

[Binder polymer]
The binder polymer contained in the photosensitive composition in the present invention is a polymer that functions as a film forming agent for the photosensitive layer. Further, the binder polymer to be used is appropriately selected according to the mode of the development treatment so that the non-image area of the photosensitive layer can be satisfactorily removed in the plate making process of the lithographic printing plate precursor. For example, in an embodiment where the development treatment is performed using an alkaline developer, the binder polymer needs to be dissolved in the alkaline developer, and therefore an organic high molecular polymer that is soluble or swellable in alkaline water is preferably used. .
As such a binder polymer, a polymer having at least a structural unit represented by the following general formulas (1) to (3) is preferable.

In the formula, R ₁ , R ₂ , and R ₃ each independently represent a hydrogen atom or a C 1 to C 6 alkyl group, and X represents —COOH, —CO—W 1 -L 1 —COOH, or —SO ₃ H. W1 represents an oxygen atom, a sulfur atom, or a —NH— group, L1 represents a divalent organic group, Y represents a —CO—O—CH ₂ —CH═CH ₂ group, —CO -W2-L2-O-CO-
CR ₄ ═CH ₂ group, W 2 represents an oxygen atom, sulfur atom, or —NH— group, and L 2 represents 2
R ₄ represents a hydrogen atom or a C 1 to C 6 alkyl group, W 3 represents an oxygen atom, a sulfur atom, or —NH— group, R ₅ represents a C 1 to C 18 alkyl group, C 5 to C 2
An alkyl group having an alicyclic structure of 0 or a group having an aromatic ring of C6 to C20;
Specific examples of the structural units represented by formulas (1) to (3) are described below, but the present invention is not limited to these.
Specific examples of formula (1) include the structural units shown below.

  Specific examples of formula (2) include the structural units shown below.

  Specific examples of the monomer that forms the structural unit of the formula (3) include methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, normal butyl (meth) acrylate, isopropyl (meth) acrylate, cyclohexyl ( Alkyl or aryl (meth) acrylates such as (meth) acrylate, n-hexyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, phenethyl (meth) acrylate, (meth) acrylate represented by the following formula Is mentioned. (In the following formula, preferred substituents for R include methyl group, ethyl group, isopropyl group, nbutyl group, tbutyl group, cyclohexyl group, phenethyl group, benzyl group, and nhexyl group.)

  In order to maintain the developability of the photopolymerizable photosensitive layer, the binder polymer to be used preferably has an appropriate molecular weight and acid value. The weight average molecular weight is 5,000 to 300,000, and the acid value is 0.009 to 3 A high molecular weight polymer of .57 meq / g, more desirably 0.35 to 3.57 meq / g is particularly preferably used.

  As long as the above molecular weight, acid value, and double bond amount are satisfied, the mixing ratio of (1), (2), and (3) may be any combination. As long as these are satisfied, structural units other than the above (1) to (3) may be further added.

  The binder polymer can be contained in an arbitrary amount in the photosensitive layer, but when it exceeds 90% by mass in all the components of the photosensitive composition, it does not give a preferable result in terms of image strength to be formed. Therefore, it is preferably 10 to 90% by mass, more preferably 30 to 80% by mass.

In the present invention, the above binder polymer and other binder polymers can be used in combination. The binder polymer that can be used in combination includes various types. For example, a water-soluble organic polymer is used. Examples of such an organic high molecular polymer include addition polymers having a carboxylic acid group in the side chain, such as JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54- No. 25957, JP 54-92723, JP 59-53836, JP 59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Cyclic acid anhydrides for acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, acidic cellulose derivatives having a carboxylic acid group in the side chain, and addition polymers having a hydroxyl group Products, polyvinyl pyrrolidone, polyethylene oxide, alcohol-soluble polyamides that can increase the strength of the cured film, and 2,2-bis (4-hydro Shifeniru) polyether of propane and epichlorohydrin.
Furthermore, Japanese Patent Publication No. 7-120040, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-12004
No. 2, JP-B-8-12424, JP-A 63-287944, JP-A 63-287947
Polyurethane resins described in JP-A-1-271741 and JP-A-11-352691 can also be used in the application of the present invention.

In an embodiment in which the development process in the plate making process is performed using a developer having a pH of 2 to 10, a hydrophobic binder polymer is used as the binder polymer.
As such a hydrophobic binder polymer, a water-insoluble polymer is preferably used. Further, the usable hydrophobic binder polymer preferably does not substantially contain an acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group, and the acid value of the binder polymer (chemical content, etc. per 1 g of the polymer) It is preferable that it is 0.3 meq / g or less, More preferably, it is 0.1 meq / g or less.
That is, the usable hydrophobic binder polymer is preferably insoluble in water and an aqueous solution having a pH of 10 or more, and the solubility of the hydrophobic binder polymer in water and an aqueous solution having a pH of 10 or more is 0.5% by mass or less. Is more preferable, and 0.1% by mass or less is more preferable. By using such a hydrophobic binder polymer, the film strength, water resistance and inking property of the photosensitive layer are improved even in an embodiment in which development processing is performed using a developer having a pH of 2 to 10, and printing durability is improved. An improvement is obtained.

As the hydrophobic binder polymer, as long as the performance of the lithographic printing plate precursor according to the present invention is not impaired, a conventionally known linear organic material having film properties can be used as long as it satisfies the above requirements. Polymers are preferred.
As an example of such a hydrophobic binder polymer, a polymer selected from acrylic resin, polyvinyl acetal resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Especially, an acrylic resin is preferable and a (meth) acrylic acid ester copolymer is preferable. More specifically, an alkyl (meth) acrylate or an aralkyl ester and an ester residue (—COOR) of (meth) acrylate ester may have —CH ₂ CH ₂ O— unit or —CH ₂ CH ₂ NH— unit as R. A copolymer with a (meth) acrylic acid ester containing is particularly preferred. The preferable alkyl group of the (meth) acrylic acid alkyl ester is an alkyl group having 1 to 5 carbon atoms, and a methyl group is more preferable. Preferable (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

Furthermore, the hydrophobic binder polymer can be provided with a crosslinking property in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, 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 or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

In the general formula (1), R ^{1 to} R ³ each independently represents a hydrogen atom or a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl which may have a substituent. A hydrogen atom or a methyl group is preferable because of high radical reactivity. Further, R ^2, R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent group, a substituted An aryl group that may have a group, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2), R ^{4 to} R ⁸ each independently represents a hydrogen atom or a monovalent organic group, and R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, or a dialkyl. Amino group, carboxyl group, alkoxycarbonyl group, sulfo group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy which may have a substituent A group, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, Examples include an arylsulfonyl group which may have a substituent. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl which may have a substituent The ru group is preferred.

Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R ¹² has the same meaning as R ¹² in general formula (1), and preferred examples are also the same.

In the general formula (3), R ⁹ represents a hydrogen atom or a monovalent organic group, preferably a hydrogen atom or an alkyl group which may have a substituent, among which a hydrogen atom, methyl The group is preferable because of high radical reactivity. R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group which may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, a substituent An arylamino group that may have, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Further, Z is an oxygen atom, a sulfur atom, -N (R ¹³⁾ -, or a phenylene group which may have a substituent. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  Hydrophobic binder polymers 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 of polymerizable compounds directly between polymers. Addition polymerization through a chain forms a cross-link between polymer molecules and cures. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the hydrophobic binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the hydrophobic binder polymer. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol.

Further, it is preferable that the binder polymer is hydrophilic from the viewpoint of improving developability with respect to an aqueous solution, and it is important that the binder polymer is compatible with the polymerizable compound contained in the photosensitive layer from the viewpoint of improving printing durability. Yes, ie lipophilic. From this point of view, in the present invention, it is also effective to allow a hydrophilic group and a lipophilic group to coexist in the hydrophobic binder polymer in order to improve developability and printing durability. As the hydrophilic group,
For example, hydroxy group, carboxylate group, hydroxyethyl group, ethyleneoxy group, hydroxypropyl group, polyoxyethyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl Those having a hydrophilic group such as a group are preferred.

The hydrophobic binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The hydrophobic binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The hydrophobic binder polymer may be used alone or in combination of two or more.
The content of the hydrophobic binder polymer is 5 to 90% by mass, preferably 10 to 70% by mass, and more preferably 10 to 60% by mass with respect to the total solid content of the photosensitive layer. Within this range, good image area strength and image formability can be obtained.

[Organic compound containing a mercapto group]
In the present invention, when hexaarylbisimidazoles are used as the polymerization initiator, it is preferable to use a specific mercapto compound in combination.
The mercapto compound which can be preferably used in the present invention is a compound selected from 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzoimidazole or a compound represented by the following formula (4).

In the formula, R ₆ is a hydrogen atom, a C1-C18 linear alkyl group or branched alkyl group, C5
Alkyl group or having an alicyclic structure to C20, a group having an aromatic ring from C6 C20, X represents an oxygen atom, a sulfur atom or represents an -N-R _7, straight of R ₇ is a C1 C18 A chain alkyl group or a branched alkyl group, an alkyl group having a C5 to C20 alicyclic structure, or a group having a C6 to C20 aromatic ring.
Preferable examples of the compound represented by the formula (4) include the following compounds.

  In addition, the usage-amount of the said mercapto compound has the preferable range of 3-30 mass% in the photosensitive composition whole component, More preferably, it is the range of 5-20 mass%.

[Co-sensitizer]
The sensitivity of the photosensitive layer can be further improved by using certain additives. Such a compound is referred to as a co-sensitizer in the present invention. These mechanisms of action are not clear, but many are thought to be based on the following chemical processes. That is, a photoreaction initiated by light absorption of the above-described photopolymerization initiation system, and various intermediate active species (radicals, peroxides, oxidizing agents, reducing agents, etc.) generated in the course of the subsequent addition polymerization reaction, It is presumed that the co-sensitizer reacts to generate a new active radical. These can be broadly divided into (a) those that can be reduced to generate active radicals, (b) those that can be oxidized to generate active radicals, and (c) radicals that are more active by reacting with less active radicals. Can be classified into those that act as chain transfer agents, but there is often no generality as to which of these individual compounds belong.

(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that the carbon-halogen bond is reductively cleaved to generate an active radical. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.
Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that the oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.
Ferrocene and iron arene complexes: An active radical can be reductively generated.

(B) Compound which is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.
Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines, and the like.
Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.

α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopronone-1 and these and a hydroxylamine were reacted, and then N—OH was etherified. Examples include oxime ethers.
Sulfinic acid salts: An active radical can be reductively generated. Specific examples include sodium arylsulfinate.

(C) Compounds that react with radicals to convert to highly active radicals or act as chain transfer agents Compounds that react with radicals to convert to highly active radicals or act as chain transfer agents include, for example, SH, PH in the molecule , SiH, and GeH are used. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals. Specifically, 2-mercaptobenzimidazoles etc. are mentioned, for example.

  Many more specific examples of these co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity. Some examples are shown below, but the present invention is not limited thereto.

  These co-sensitizers can also be subjected to various chemical modifications for improving the characteristics of the photosensitive layer of the lithographic printing plate precursor as in the case of the sensitizing dye. For example, bonds with sensitizing dyes, titanocene, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, improved compatibility, introduction of substituents for suppressing crystal precipitation, substituents for improving adhesion Methods such as introduction and polymerization can be used. These co-sensitizers can be used alone or in combination of two or more. The amount used is 0.05 to 100 parts by mass, preferably 1 to 80 parts by mass, and more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the compound having an ethylenically unsaturated double bond.

[Microcapsule]
In the present invention, as a method for causing the photosensitive layer to contain the above-described photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

  As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in US Pat. Nos. 2,800,547 and 2,800,498, each specification of US Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by precipitation of polymer, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

[Other photosensitive layer components]
The photosensitive layer of the present invention can further contain various additives as required. These will be described below.

(Surfactant)
In the present invention, it is preferable to use a surfactant in the photosensitive layer in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorochemical surfactant described in Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the photosensitive layer.

(Hydrophilic polymer)
In the present invention, a hydrophilic polymer can be contained in order to improve developability and dispersion stability of microcapsules.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The hydrophilic polymer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the photosensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Coloring agent)
In the present invention, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Industrial Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI1451)
70B), malachite green (CI42000), methylene blue (CI52015) and the like, and dyes described in JP-A-62-293247. In addition, pigments such as phthalocyanine pigments (CI Pigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, carbon black, titanium oxide and the like can also be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording material.

(Bake-out agent)
In the photosensitive layer of the present invention, a compound that changes color by an acid or a radical can be added in order to form a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass relative to the solid content of the photosensitive layer.

(Polymerization inhibitor)
It is preferable to add a small amount of a thermal polymerization inhibitor to the photosensitive layer of the present invention in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the photosensitive layer.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photosensitive layer.

(Higher fatty acid derivatives, etc.)
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photosensitive layer of the present invention so that it is unevenly distributed on the surface of the photosensitive layer during the drying process after coating. May be. The amount of the higher fatty acid derivative added is preferably from about 0.1 to about 10% by weight based on the total solid content of the photosensitive layer.

(Plasticizer)
The photosensitive layer of the present invention may contain a plasticizer. Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in. The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photosensitive layer.

(Inorganic fine particles)
The photosensitive layer of the present invention may contain inorganic fine particles in order to improve the cured film strength of the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like. The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the photosensitive layer, sufficiently retains the film strength of the photosensitive layer, and does not easily cause stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Low molecular hydrophilic compound)
The photosensitive layer of the present invention can contain a hydrophilic low molecular weight compound for improving developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Organic carboxylic acids such as salts, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, amino acids and their salts, and organic quaternary amines such as tetraethylamine hydrochloride Salt, and the like.

  Further, in the photosensitive layer of the lithographic printing plate precursor according to the present invention, in order to enhance the effect of heating / exposure after development for the purpose of improving film strength (press life), a UV initiator, Addition of a crosslinking agent etc. can also be performed.

Next, the planographic printing plate precursor will be described.
The lithographic printing plate precursor used in the present invention has at least a photosensitive layer on a support.
[Support]
As the support in the present invention, a conventionally known support for use in a lithographic printing plate precursor can be used without limitation.
The support used is preferably a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc). , Copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), Paper or plastic film, etc. on which such metals are laminated or vapor-deposited are included. Appropriate known physical and chemical treatments are applied to these surfaces for the purpose of imparting hydrophilicity and improving strength as necessary. You may give it.

  In particular, preferred supports include paper, polyester film or aluminum plate, among which dimensional stability is good, relatively inexpensive, and a surface with excellent hydrophilicity and strength is provided by surface treatment as required. An aluminum plate that can be formed is more preferable. A composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

The aluminum plate as the most preferable support in the present invention is a metal plate mainly composed of dimensionally stable aluminum, and contains pure aluminum plate, aluminum as a main component, and a trace amount of foreign elements. An alloy plate or aluminum (alloy) is selected from a laminated or vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or an aluminum alloy is generically used as an aluminum support. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.

Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user.
Such an aluminum support may be subjected to a surface treatment such as the following surface roughening treatment or anodizing treatment, if necessary. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to the roughening treatment, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like is performed if necessary to remove rolling oil on the surface.

(Roughening treatment)
The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface). These roughening methods can be used alone or in combination.
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.
Among them, a method usefully used for roughening is an electrochemical method in which roughening is performed chemically in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity at the time of anode is 50 C / dm ^{2 to} 400 C / dm ² . It is a range. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, alternating at a current density of 100C / dm ² ~400C / dm ² It is preferable to perform direct current electrolysis.

The aluminum support thus roughened may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like, and preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C. In order to remove dirt (smut) remaining on the surface after etching, pickling is performed. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, Japanese Patent Application Laid-Open No. 53-1 is preferable.
Examples thereof include a method of contacting with 15 to 65% by mass of sulfuric acid at a temperature of 50 to 90 ° C. as described in Japanese Patent No. 2739, and a method of alkali etching as described in Japanese Patent Publication No. 48-28123. The method and conditions are not particularly limited as long as the surface roughness Ra of the treated surface is about 0.2 to 0.5 μm after the treatment as described above.

(Anodizing treatment)
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions and the like, and the concentration is 0 to 10,000 ppm. May be included. There are no particular limitations on the conditions of the anodizing treatment, but the treatment is preferably carried out by direct current or alternating current electrolysis at a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter, a treatment liquid temperature of 10 to 70 ° C. . The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. Preferably it is the range of 0.5-1.0 micrometer. The support prepared by the above treatment is treated so that the pore diameter of the micropores existing in the anodized film is in the range of 5 to 10 nm and the pore density is in the range of 8 × 10 ¹⁵ to 2 × 10 ¹⁶ pieces / m ^2. It is preferred that the conditions are selected.

  The substrate used in the present invention may be a substrate having the surface treatment as described above and having an anodized film as it is, but for further improvements such as adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation, etc. As necessary, the micropore enlargement treatment, the micropore sealing treatment of the anodized film, and the aqueous solution containing a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365 It is possible to appropriately select and perform surface hydrophilization treatment that is immersed in the substrate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

As the hydrophilic treatment on the surface of the support, a hydrophilic treatment with silicate or polyvinylphosphonic acid is preferred. In this case, the coating is formed with a Si or P element amount of ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The coating amount can be measured by fluorescent X-ray analysis.

  The hydrophilization treatment is carried out by applying an anodized film to an aqueous solution containing 1 to 30% by mass, preferably 2 to 15% by mass of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. This is carried out by immersing the aluminum support on which is formed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or Group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. Surface obtained by combining a support having electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 with the above-described anodizing treatment and hydrophilization treatment Processing is also useful.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferred compounds include compounds having a polymerizable group such as a methacryl group and an allyl group and a support-adsorbing group such as a sulfonic acid group, a phosphoric acid group, and a phosphoric acid ester group. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

  Specific examples of the intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, Kaihei 3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, JP-A-8-202525 No. 8-320551, JP-A-9-34104, JP-A-9-236911, JP-A-9-269593, JP-A-10-69092, JP-A-10-115931, JP-A-10-161317, JP-A-10 -260536, JP-A-10-282682, JP-A-11-84684, JP-A-11-38635, JP-A-11-38629, JP-A-10-282645, JP-A-1 0-301262, JP-A-11-24277, JP-A-11-109641, JP-A-10-319600, JP-A-11-84684, JP-A-11-327152, JP-A2000-10292, JP2000-2000A. -235254, Unexamined-Japanese-Patent No. 2000-352824, Unexamined-Japanese-Patent No. 2001-209170, Unexamined-Japanese-Patent No. 2001-175001, etc. can be mentioned.

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Preparation of lithographic printing plate precursor]
The planographic printing plate precursor according to the invention has a photosensitive layer on a support. Such a lithographic printing plate precursor can be produced by coating a photosensitive layer coating solution containing the above-described various components on a support.

When coating the photosensitive layer, the photosensitive composition is dissolved or dispersed in an appropriate solvent (organic solvent, water) to form a photosensitive layer coating solution, which is applied onto the support or the undercoat layer.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, di Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There is ethyl. These solvents can be used alone or in combination. The solid content in the photosensitive layer coating solution is suitably 2 to 50% by mass.

The coating amount of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the developability, and the strength and printing durability of the exposed film, and is preferably selected as appropriate according to the application. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. For the lithographic printing plate precursor for scanning exposure, the coating amount is suitably in the range of about 0.1 g / m ² to about 10 g / m ² in terms of the mass after drying. More preferably from 0.5 to 5 g / m ^2.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

The characteristics of the photosensitive layer according to the present invention vary depending on the mode of development processing. For example, in an embodiment in which the development process is performed using an alkaline developer, the photosensitive layer has a development rate of 80 nm / sec or more in an unexposed portion with respect to an alkaline developer having a pH of 10 to 13.5, and exposure of the alkaline developer. The permeation rate at the part is preferably 50 nF / sec or less.
Hereinafter, a method for measuring “development speed of an unexposed portion with respect to an alkali developer” and “penetration speed of an alkali developer at an exposed portion” in the present invention will be described in detail.

[Measurement of development speed of unexposed area with alkaline developer]
Here, the developing speed of the unexposed portion of the photosensitive layer with respect to the alkaline developer is a value obtained by dividing the film thickness (nm) of the photosensitive layer by the time (sec) required for development.
In the present invention, the developing speed is measured by immersing an unsupported photosensitive layer on an aluminum support in a constant alkaline developer (30 ° C.) having a pH in the range of 10 to 13.5. The dissolution behavior was investigated with a DRM interference wave measuring device. 1 shows a schematic diagram of a DRM interference wave measuring apparatus for measuring the dissolution behavior of a photosensitive layer. FIG. In the present invention, a change in film thickness was detected by interference using light of 640 nm. When the development behavior is non-swelling development from the surface of the photosensitive layer, the film thickness gradually decreases with respect to the development time, and an interference wave corresponding to the thickness can be obtained. Further, in the case of swelling dissolution (film removal dissolution), the film thickness changes due to the penetration of the developer, so that a clean interference wave cannot be obtained.

The measurement is continued under these conditions, and the development speed is expressed by the following equation from the time (s) until the photosensitive layer is completely removed and the film thickness becomes 0 (development completion time) and the film thickness (nm) of the photosensitive layer. It can ask for. It is determined that the higher the development speed, the easier the film is removed by the developer and the better the developability.
Development speed (of unexposed area) = [photosensitive layer thickness (nm) / recording completion time (sec)]

[Measurement of penetration rate of alkaline developer at exposed area]
The permeation rate of the alkali developer at the exposed portion is a value indicating the rate of change in capacitance (nF) when the photosensitive layer is formed on a conductive support and immersed in the developer.
As a method for measuring the electrostatic capacity, which is a measure of permeability in the present invention, exposure is carried out at a predetermined exposure amount on an aluminum support in a constant alkali developer (28 ° C.) in the range of pH 10 to 13.5. And a method in which a hardened photosensitive layer is immersed as one electrode, a conductive wire is connected to an aluminum support, and a voltage is applied to the other using a normal electrode. After the voltage is applied, the developer permeates the interface between the support and the photosensitive layer as the immersion time elapses, and the capacitance changes.

From the time (sec) required until this change in capacitance becomes constant and the saturation value (nF) of the capacitance of the photosensitive layer, it can be obtained by the following equation. It is determined that the smaller the permeation rate, the lower the permeability of the developer.
Developer penetration speed (of exposed area) = [Saturation value of electrostatic capacitance of photosensitive layer (nF) / Time required for capacitance change to be constant (sec)]

  In the physical properties of the photosensitive layer in the lithographic printing plate precursor according to the invention, the development rate of the unexposed area with an alkaline developer having a pH of 10 to 13.5 as measured above is more preferably 80 to 400 nm / sec, and still more preferably, 90 to 200 nm / sec. On the other hand, the penetration rate of the exposed portion of the same alkali developer is more preferably 0 to 50 nF / sec, and still more preferably 0 to 10 nF / sec.

Control of the developing speed of the unexposed part of the photosensitive layer and the penetration speed of the alkaline developer in the exposed photosensitive layer, that is, the exposed part can be performed by a conventional method. Addition of a hydrophilic compound is useful for improving the development speed of the part, and means for adding a hydrophobic compound is useful for suppressing penetration of the developer into the exposed part.
By using the above-mentioned specific binder polymer, the developing speed of the photosensitive layer and the permeation speed of the developer can be easily adjusted to the above preferred ranges.
On the other hand, the physical property values of the photosensitive layer measured using a developer having a pH of 2 to 10 instead of the alkali developer are the same in the embodiment in which the development process in the plate making process is performed using a developer having a pH of 2 to 10. It is preferable to be in the range (the developing speed of the unexposed area is 80 nm / sec or more and the penetration speed of the alkaline developer in the exposed area is 50 nF / sec or less).

[Protective layer]
Since the photosensitive layer of the lithographic printing plate precursor according to the present invention is a polymerizable negative photosensitive layer as described above, it is usually further protected on the photosensitive layer in order to perform exposure in the air. A layer (also referred to as an overcoat layer) is preferably provided. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer, and enables exposure in the atmosphere. To do. Therefore, the desired property of such a protective layer is that the permeability of low molecular compounds such as oxygen is low. The protective layer used in the present invention has an oxygen permeability A of 1.0 ≦ A ≦ 20 (mL / m ² · day) at 25 ° C. and 1 atm.
) Is preferable. When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and further preferably 2.0 ≦ A ≦ 10.0 (m
L / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially impede the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. Such a device relating to the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / Examples include water-soluble polymers such as vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. Can be used alone or in combination. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those having a hydrolysis degree of 71 to 100% and a polymerization degree in the range of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, manufactured by Kuraray Co., Ltd. PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like. These can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure. In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesive force is likely to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563 disclose an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and the like and laminating on the photosensitive layer.
Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method of the protective layer is described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.
Therefore, in the present invention, it is preferable to use polyvinyl alcohol and polyvinyl pyrrolidone in combination from the viewpoints of adhesive strength, sensitivity, and unnecessary fog. The addition ratio (mass ratio) is preferably 3/1 or less of polyvinyl alcohol / polyvinylpyrrolidone. The coating weight is preferably ^{1.0g / m 2 ~3.0g / m 2} .

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin flat plate shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any one of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.

In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. As the synthetic mica, fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀
) F ₂ , Potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) Non-swelling mica such as F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (N
_{a, Li) Mg 2 Li (} Si 4 O 10) F 2, montmorillonite of Na or Li hectorite _{(Na, Li) 1/8 Mg 2} /5 Li 1/8 (Si 4 O 10) F 2 , etc. Examples include swelling mica. Synthetic smectite is also useful.

In the present invention, among the inorganic layered compounds, fluorine-based swellable mica, which is a synthetic inorganic layered compound, is particularly useful. That is, this swellable synthetic mica and swellable viscosity minerals such as montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10-15A, Atomic substitution is significantly greater than other viscous minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have this tendency and are useful in the present invention, and swellable synthetic mica is particularly preferably used.

  As the shape of the inorganic layered compound used in the present invention, from the viewpoint of diffusion control, the smaller the thickness, the better. The plane size is as long as it does not hinder the smoothness of the coated surface or the transmittance of actinic rays. Larger is better. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  Next, an example of a general dispersion method of the inorganic stratiform compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable layered compound mentioned above as a preferred inorganic layered compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  In addition to the inorganic layered compound, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, known additives for improving the adhesion to the photosensitive layer and the temporal stability of the coating solution may be added to the coating solution.

The protective layer coating solution thus prepared is applied onto the photosensitive layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

<Plate making method>
Hereinafter, a method for making a lithographic printing plate precursor according to the present invention will be described.
The plate-making method of the lithographic printing plate precursor according to the present invention is a plate-making method in which the lithographic printing plate precursor as described above is exposed using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm. In the exposure apparatus, the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beam spots are adjacent so as to partially overlap. Lined up in the sub-scanning direction, the lithographic printing plate precursor is placed on an inner drum exposure device, and then image recording is performed by exposure of the light beam spot shape.

〔exposure〕
First, the inner drum exposure apparatus used in the present invention will be described.
The inner drum exposure apparatus used in the present invention is such that the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beams The spots are arranged adjacent to each other so as to partially overlap in the sub-scanning direction.

  More specifically, a light beam modulated in accordance with image information is applied to a recording medium (lithographic printing plate precursor) held on an arc-shaped inner peripheral surface formed on a drum support (see FIG. 1). In an inner drum exposure apparatus that records an image by deflecting and scanning with a reflecting mirror surface that is rotationally driven by a scanning means, the light source that emits a light beam is disposed in an optical path between the light source and the scanning means. A quarter-wave plate that converts the emitted linearly polarized light beam into circularly-polarized light, a surface disposed between the quarter-wave plate and the reflecting mirror surface, and a surface on which the light beam enters and exits the reflecting mirror surface and crystal light Arranged so that the axis is substantially parallel, the light beam is divided into an ordinary ray and an extraordinary ray in parallel with equal amounts of light, and the two beam spots are adjacently aligned in the sub-scanning direction. Reflection to form beam spot shape The exposure apparatus and the like having an optical element of the mounted uniaxial crystal to a surface and integrally rotated.

By configuring as described above, in this inner drum exposure apparatus, a light beam that is substantially linearly polarized light emitted from the light source is converted into circularly polarized light when passing through the quarter-wave plate 32 disposed on the optical path. The The light beam converted into circularly polarized light is split into an ordinary ray and an extraordinary ray when passing through the optical element of the uniaxial crystal. This beam-divided ordinary ray and extraordinary ray have the same intensity, and are, for example, beam-divided in the sub scanning direction. The ordinary ray and the extraordinary ray split into beams in the sub-scanning direction at the same intensity are reflected by the reflecting mirror surface, and become a substantially rectangular distribution in the sub-scanning direction, for example, at the condensing point on the recording medium, and the edge The light is focused on the beam spot where the part becomes steep. In this inner drum exposure apparatus, the beam spot is divided into a substantially rectangular distribution, and the beam spot having a steep edge is, for example, a state in which the beam spot shape is elongated in the sub-scanning direction (that is, the beam The exposure process is performed while always maintaining the longitudinal direction of the distribution of the spot having a substantially rectangular shape along the sub-scanning direction (direction perpendicular to the main scanning direction). Therefore, the intensity distribution of the beam spot on the recording medium is substantially rectangular in the sub-scanning direction, and the edges on both sides of the condensing point are sharp. The image unevenness in the sub-scanning direction is preferably suppressed. Therefore, the image when the FM screen is recorded is
The ratio of halftone image (halftone dot area ratio characteristic) is drastically changed so that the circumference of the recording pixel does not fluctuate a little depending on the recording condition such as light power fluctuation and the number of printed sheets and the developing condition such as the developing degree of the automatic processor. Therefore, it is difficult to cause density fluctuation, and recording can be performed so that a halftone can be stably expressed using an FM screen.

  The inner drum exposure apparatus scans a recording medium held on an arc-shaped inner peripheral surface by deflecting a light beam modulated in accordance with image information with a reflecting mirror surface driven by rotation of scanning means. In the inner drum exposure apparatus for recording an image, random polarizing means for causing a randomly polarized light beam to enter the reflecting mirror surface of the scanning means, a surface on which the randomly polarized light beam enters and exits the reflecting mirror surface, and crystal light Arranged so that the plane including the axis and the normal line is the same plane, the light beam is split into an ordinary ray and an extraordinary ray with equal amounts of light and shifted in parallel with each other so that the two beam spots partially overlap. Exposure is performed by an exposure apparatus having a beam spot shape arranged adjacent to the sub-scanning direction and having an optical element of a uniaxial crystal mounted so as to rotate integrally with the reflecting mirror surface It may be.

  By configuring as described above, in this inner drum exposure apparatus, the light beam randomly polarized by the random polarization means is split into an ordinary ray and an extraordinary ray when passing through the optical element of the uniaxial crystal. . This beam-divided ordinary ray and extraordinary ray have the same intensity, and are, for example, beam-divided in the sub-scanning direction. The ordinary ray and the extraordinary ray that are split in the sub-scanning direction with the same intensity are reflected by the reflecting mirror surface, and become a substantially rectangular distribution extending elongated in the sub-scanning direction, for example, at the condensing point on the recording medium. In addition, the light beam is focused on a beam spot having a sharp edge. In this inner drum exposure apparatus, the beam spot is divided into a substantially rectangular distribution, and the beam spot having a steep edge is, for example, a state in which the beam spot shape is elongated in the sub-scanning direction (that is, the beam Since the exposure process is performed while always maintaining the sub-scanning direction (direction perpendicular to the main scanning direction) in the longitudinal direction of the distribution of the spot having a substantially rectangular shape, the intensity distribution of the beam spot on the recording medium is Since it has a substantially rectangular shape in the sub-scanning direction and the edges on both sides of the focal point become sharp, it is hardly affected by fluctuations in the color development threshold of the recording medium and intensity fluctuations of the laser beam, etc. Image unevenness is suitably suppressed. Therefore, the image when the FM screen is recorded has a halftone dot so that the circumference of the recording pixel does not fluctuate at all due to recording conditions such as light power fluctuation and the number of printed sheets, development conditions such as the degree of development of the automatic processor, and the like. It is possible to prevent the image ratio (halftone dot area ratio characteristic) from changing abruptly to make it difficult to cause density fluctuations, and to record halftones stably using an FM screen.

  Further, as the inner drum exposure apparatus, a recording medium is held on an arc-shaped inner peripheral surface formed on a drum support, and a plurality of light beams modulated in accordance with image information are deflected to form an arc-shape. In an inner drum exposure apparatus for recording an image by scanning on a recording medium held on a light beam, a light beam output means for emitting a plurality of light beams and a central axis of an arcuate inner peripheral surface of the drum support are rotated. The reflecting means has a reflecting mirror surface, and a plurality of light beams are reflected by a rotating reflecting mirror surface, so that the scanning means for scanning the recording medium and the light beam relative to each other in a plane perpendicular to the rotation axis of the scanning means. Optically deflecting two-dimensionally to cause displacement in the main scanning direction and sub-scanning direction on the recording medium, and the position of the light beam on the recording medium by the light deflecting means to rotate the reflecting mirror surface In sync with 1/4 wavelength that is arranged in the optical path between the control means for controlling, the light beam output means and the scanning means, and converts each of a plurality of linearly polarized light beams emitted from the light beam output means into circularly polarized light. The plate is disposed between the quarter-wave plate and the reflecting mirror surface so that the plane on which the light beam enters and exits the reflecting mirror surface and the plane including the crystal optical axis and the normal line are flush with each other. Each of the plurality of light beams is split into an ordinary ray and an extraordinary ray with equal amounts of light to form a beam spot shape adjacent to each other in the sub-scanning direction so that the two beam spots partially overlap each other. It is also possible to use an exposure apparatus having a uniaxial crystal optical element mounted so as to rotate integrally therewith.

  By configuring as described above, the control unit controls the displacement position of the light beam on the recording medium by the light deflecting unit in synchronization with the rotation of the reflecting mirror surface, so that a plurality of light beams emitted from the light beam output unit are controlled. The light beam is deflected relatively two-dimensionally in a plane perpendicular to the rotation axis of the scanning means so that the required light beam is displaced in the main scanning direction and the sub-scanning direction on the recording medium by the light deflecting means. And scan. At this time, a plurality of light beams that are substantially linearly polarized light emitted from the light beam output means are converted to circularly polarized light when passing through a quarter-wave plate disposed on the optical path leading to the light deflecting means. . The plurality of light beams converted to circularly polarized light are split into ordinary rays and extraordinary rays, respectively, when passing through the optical element of the uniaxial crystal. This beam-divided ordinary ray and extraordinary ray have the same intensity, and are, for example, beam-divided in the sub-scanning direction. Each ordinary ray and extraordinary ray divided in the sub-scanning direction at the same intensity is reflected by the reflecting mirror surface, and is distributed in a substantially rectangular shape, for example, in the sub-scanning direction at each condensing point on the recording medium. And the light beam is focused on a beam spot having a sharp edge. In this inner drum exposure apparatus, the beam is divided into a substantially rectangular distribution, and each of the plurality of beam spots having sharp edges is, for example, a state in which the beam spot shape is elongated in the sub-scanning direction ( That is, since the exposure process is always performed while maintaining the longitudinal direction of the distribution of the beam spot in a substantially rectangular shape along the sub-scanning direction (direction perpendicular to the main scanning direction), each beam spot on the recording medium is performed. The intensity distribution is substantially rectangular in the sub-scanning direction, and the edges on both sides of the condensing point are sharp, so it is hardly affected by fluctuations in the color development threshold of the recording medium or fluctuations in the intensity of the laser beam, Image unevenness in the sub-scanning direction is preferably suppressed. Therefore, the image when the FM screen is recorded has a halftone dot so that the circumference of the recording pixel does not fluctuate at all due to recording conditions such as light power fluctuation and the number of printed sheets, development conditions such as the degree of development of the automatic processor, and the like. It is possible to prevent the image ratio (halftone dot area ratio characteristic) from changing abruptly to make it difficult to cause density fluctuations, and to record halftones stably using an FM screen.

  The exposure apparatus used in the present invention is equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm, and in particular, a 405 nm laser commercially available from Nichia Corporation or the like is preferably used.

By using the inner drum exposure apparatus described above, it is possible to record a high-precision image at a high speed by simultaneously recording an image with a plurality of light beams emitted from the light beam output means.
Further, by using the inner drum exposure apparatus described above, it is possible to record an image on an FM screen at the time of exposure, and it is possible to record a halftone expression stably using the FM screen.

Hereinafter, a specific exposure method using the inner drum exposure apparatus and the exposure apparatus used in the present invention will be specifically described with reference to the drawings, but the present invention is not limited to these.
A first embodiment relating to the inner drum exposure apparatus will be described with reference to FIGS. The inner drum exposure apparatus according to the first embodiment is configured to be able to record halftone stably using an FM screen. In this inner drum exposure apparatus, if the circumference of the recording pixel changes even slightly due to recording conditions such as light power fluctuation and the number of printed sheets, development conditions such as the degree of development of an automatic developing machine, etc. In order to reduce the possibility that density fluctuations are likely to occur because the characteristic) is likely to change abruptly, measures are taken to make the shape of the recording spot in the sub-scanning direction rectangular and make the spot diameter in the main scanning direction smaller than the recording pixel. .

As shown in the schematic block diagram of FIG. 1, the inner drum exposure apparatus 10 is configured with a drum support 12 having a circular arc inner peripheral surface shape (a shape constituting a part of a cylindrical inner peripheral surface) as a base. A recording medium 14 (lithographic printing plate precursor) is supported along the inner peripheral surface of the drum support 12.

  The inner drum exposure apparatus 10 is in a state in which an unrecorded recording medium 14 is supplied and reliably brought into close contact with the inner peripheral surface of the drum support 12 by a recording medium 14 supply / discharge device (not shown). Then, an exposure process is performed, and an operation for discharging the exposed recording medium 14 from the drum support 12 to the outside is performed.

  In the inner drum exposure apparatus 10, a spinner mirror device 16 as a scanning unit is disposed at the center of the arc of the drum support 12. The spinner mirror device 16 is configured such that a columnar rotation shaft 18 can be rotated by a motor 20 as a drive source with a central axis as a rotation axis (coincident with the arc central axis of the drum support 12). A reflecting mirror surface 18A that forms an angle of 45 degrees with respect to the rotation axis is formed at the tip of the rotation axis 18 of the spinner mirror device 16.

  The spinner mirror device 16 as the scanning means is moved and scanned at a constant speed in the axial direction of the center axis of the arc of the drum support 12 (the direction of the arrow C, which is the left-right direction in FIG. 1) by a sub-scanning movement means (not shown). Is done. The spinner mirror device 16 is controlled to rotate by a spinner driver 22 and is controlled to move in the sub-scanning direction by a sub-scanning moving unit (not shown).

  The inner drum exposure apparatus 10 is configured to perform main scanning on the recording surface of the recording medium 14 arranged on the inner peripheral surface of the drum support 12 by performing beam splitting.

  For this reason, the optical element 26 of a uniaxial crystal is disposed on the spinner mirror device 16 side by a holder 24 fixed so as to rotate integrally with the rotation shaft 18. The holder 24 is formed in a cylindrical shape, for example, and is formed by drilling a through hole 24A (shown in FIG. 2) for allowing the light beam reflected by the reflecting mirror surface 18A to pass to the recording medium 14 side.

  The uniaxial crystal optical element 26 is disposed in the optical path between the light-collecting lens 28 on the light source side and the reflecting mirror surface 18A of the spinner mirror device 16, and rotates integrally with the reflecting mirror surface 18A by the support means. You may comprise and comprise. The inner drum exposure apparatus 10 may be variously configured using, for example, a uniaxial crystal optical element 26 that is divided in parallel by a beam display prism, for example.

  As this uniaxial crystal optical element 26, as shown in FIG. 2, for example, a beam display prism whose crystal optical axis is inclined by 45 degrees with respect to the normal of the incident surface is used.

  When a circularly polarized light beam (which may be a randomly polarized light beam modulated based on an image signal by a random polarization means (not shown)) is incident on the uniaxial crystal optical element 26, as shown in FIG. The light beam is split into an ordinary ray Po and an extraordinary ray Pe with an equal amount of light. In this case, the ordinary ray Po and the extraordinary ray Pe are shifted in parallel with each other. For example, when the optical element 26 of the uniaxial crystal has a light wavelength of 405 nm and the shift amount (division width) is set to 5.5 μm, quartz is used as the material of the optical element 26 of the uniaxial crystal, and the thickness thereof. Is about 0.904 mm. The crystal used as the material of the uniaxial crystal optical element 26 is advantageous in that it is stable in material and low in cost, and can cope with a circle having a diameter of 30 mm.

In this way, when a light beam is split into an ordinary ray Po and an extraordinary ray Pe with equal amounts of light and parallel-shifted (an angle-division method may be used) to form a beam spot shape that overlaps the two (beam splitting) 4), for example, as shown in FIG. 4, two Gaussian beams having a half width of 5 μm are shifted by 5.5 μm and are superposed (beam-divided state). On the other hand, it becomes a state closer to a rectangular shape, and also becomes sharp in the main scanning direction (the edge portion of the beam spot becomes steep).

This is a half-width 8.8 μm (1 / e ²⁾ which is a conventional Gaussian beam spot shape.
Compared with the comparative example of FIG. 5 showing the case of a width of 15 μm), the conventional beam spot shape with a Gaussian distribution is circular in cross section and does not extend in the sub-scanning direction, and the beam spot shape gently spreads. The difference in the effect is obvious because the state is gentle (the edge portion of the beam spot is gentle) also in the main scanning direction.

  As shown in FIG. 3, the inner drum exposure apparatus 10 includes a surface on which a light beam enters and exits the reflecting mirror surface 18 </ b> A of the spinner mirror device 16, and a crystal optical axis and a normal line in the uniaxial crystal optical element 26. By arranging the uniaxial crystal optical element 26 so that the plane is the same plane, two beam spots are superposed in the sub-scanning direction (adjacent so that the two beam spots partially overlap). (A state of being aligned in the sub-scanning direction).

  As shown in FIG. 1, the inner drum exposure device 10 projects a light beam or a randomly polarized light beam on the spinner mirror device 16 side in order to perform beam division and perform main scanning on the recording surface of the recording medium 14. An optical system on the light source side is provided.

  This optical system on the light source side is a semiconductor laser light source (LD) 30 that outputs a laser beam L consisting of substantially linearly polarized light, and the laser beam L emitted from the semiconductor laser light source 30 is collected on the exposure surface of the recording medium 14. A light collecting optical system. As the semiconductor laser light source 30, a single transverse mode semiconductor laser having an intensity distribution in which the center light intensity is high and the light intensity gradually decreases with increasing distance from the center can be used.

  This optical system on the light source side is configured by sequentially arranging a quarter-wave plate 32, a reflecting mirror 34, a reflecting mirror 36, and a condenser lens 28 from the semiconductor laser light source 30 side.

  The quarter wavelength plate 32 is converted into circularly polarized light when the laser beam L made of linearly polarized light emitted from the semiconductor laser light source 30 passes through the quarter wavelength plate 32. Then, the laser beam L converted into circularly polarized light is condensed by the condenser lens 28 and then transmitted through the optical element 26 of the uniaxial crystal, so that the circularly polarized laser beam L is split with equal light quantity. Then, the two beam spots can be superimposed in the sub-scanning direction by being shifted in parallel with each other, and the direction in which the beams are split with the same light amount and shifted in parallel with each other is a predetermined incident on the reflecting mirror surface 18A of the spinner mirror device 16. The light is incident in a direction parallel to the reflecting surface, reflected by the reflecting mirror surface 18A, and focused on the recording medium 14 placed on the inner peripheral surface of the drum support 12 with a substantially rectangular distribution in the sub-scanning direction. Then, the light is condensed and irradiated, and an exposure process is performed.

  In this optical system on the light source side, when the semiconductor laser light source 30 emits a laser beam L that is circularly or randomly polarized, the optical system on the light source side that does not use the quarter wavelength plate 32 is used. To do.

  As shown in FIG. 1, the inner drum exposure apparatus 10 performs an operation of recording an image on the recording medium 14 while controlling the spinner mirror device 16 and the semiconductor laser light source 30 by the central controller 40. In this inner drum exposure apparatus 10, when image information to be exposed is input from an input device (not shown) and a command to start exposure processing is transmitted to the central control apparatus 40, the central control apparatus 40 performs image processing based on the image information to be exposed. A signal is generated and this image signal is transmitted to the laser driver 42. Then, the laser driver 42 drives and controls the semiconductor laser light source 30, emits a laser beam L modulated based on the image signal, and irradiates the spinner mirror device 16 side by the optical system on the light source side.

  At the same time, the central controller 40 controls the rotation of the motor 20 to rotate the reflecting mirror surface 18A, and reflects the laser beam L incident on the reflecting mirror surface 18A from the optical system on the light source side to the recording medium 14. Thus, scanning exposure in the main scanning direction is performed, and a control signal is transmitted to the spinner driver 22. The spinner driver 22 that has received this control signal controls a sub-scanning moving means (not shown), and moves the spinner mirror device 16 in the axial direction of the center axis of the arc of the support 12 (the direction of the arrow C, which is the left-right direction in FIG. 1). To scan at a constant speed. Thus, a two-dimensional image is recorded on the entire recording surface of the recording medium 14 by moving the spinner mirror device 16 in the sub-scanning direction while performing scanning exposure in the main scanning direction by the spinner mirror device 16. Process.

  Next, the operation and operation of the inner drum exposure apparatus according to the first embodiment will be described.

  In the inner drum exposure apparatus 10, the laser beam L modulated and output according to image information from the semiconductor laser light source 30 controlled by the central controller 40 and the laser driver 42 enters the quarter wavelength plate 32. The laser beam L, which is substantially linearly polarized light incident on the quarter-wave plate 32, is converted into circularly polarized light, reflected by the reflecting mirror 34 and the reflecting mirror 36, and condensed by the condensing lens 28, and is made of a uniaxial crystal. The light enters the optical element 26. The laser beam L which is circularly polarized light is split into an ordinary ray Po and an extraordinary ray Pe when passing through the optical element 26 of a uniaxial crystal. Note that the refraction angle of the extraordinary ray Pe can be arbitrarily adjusted depending on the thickness and material of the optical element 26 of the uniaxial crystal with respect to the optical axis direction. Further, the uniaxial crystal optical element 26 sets the same intensity of the ordinary ray Po and the extraordinary ray Pe which are beam-divided in the sub-scanning direction.

  The ordinary ray Po and the extraordinary ray Pe, which are split into beams in the sub-scanning direction by the optical element 26 of the uniaxial crystal and whose intensity is adjusted, are reflected by the reflecting mirror surface 18A and are incident on the condensing point on the recording medium 14 in the sub-scanning direction. The light is collected in a substantially rectangular distribution. That is, in this inner drum exposure apparatus 10, the beam is split into a substantially rectangular distribution, and the beam spot having a sharp edge is elongated in the sub-scanning direction (that is, the substantially rectangular shape of the beam spot). Since exposure processing is performed while always maintaining the longitudinal direction of the distribution along the sub-scanning direction (a direction orthogonal to the main scanning direction), the image when the FM screen is recorded can be changed in optical power or printed. The ratio of halftone image (halftone area ratio characteristic) is prevented from abruptly changing so that the circumference of the recording pixel does not change at all due to the recording condition such as the number of sheets and the developing condition such as the developing degree of the automatic processor. Therefore, it is difficult to cause density fluctuations, and recording can be performed so that a halftone can be stably expressed using an FM screen.

  Next, a second embodiment relating to the inner drum exposure apparatus will be described with reference to FIGS. First, the principle according to the second embodiment will be described with reference to FIGS. 7A to 7C and FIGS. 8A and 8B.

When the reflecting mirror surface 18A of the spinner mirror device 16 as the scanning means is in the direction of FIG. 7A (the minor axis of the reflecting mirror surface 18A coincides with the Y axis), the laser beam L0 incident on the center of the reflecting mirror surface 18A along the Z axis. Is deflected by −θX in the X-axis direction with respect to the spinner mirror device 16, the reflected laser beam L0 is displaced by + Δz in the Z direction within a predetermined plane orthogonal to the X-axis. Further, as shown in FIG. 7B, when the laser beam L0 is deviated by + θY in the Y-axis direction with respect to the spinner mirror device 16, the reflected laser beam L0 is reflected in a predetermined plane orthogonal to the X-axis. Displace by + Δy in the Y direction. Therefore, as shown in FIG. 7C, the reflected laser beam L0 can be relatively two-dimensionally displaced on the recording medium 14 by deflecting the laser beam L0 by θXY in the X and Y axis directions. it can. Note that the two laser beams may be displaced in the respective directions by the respective distances so that the reflected laser beams are relatively two-dimensionally displaced on the recording medium.

  Here, by deflecting the laser beam # 1 by a predetermined amount in the minus direction of the X axis and the plus direction of the Y axis, the reflected laser beams # 1 and # 2 are Z on the XZ plane shown in FIG. 8A. The arrangement can be corrected along the axial direction. Similarly, when the reflecting mirror surface 18A of the spinner mirror device 16 is in the direction of FIG. 8B, the reflected laser is deflected by a predetermined amount in the plus direction of the X axis and the plus direction of the Y axis. Beams # 1 and # 2 can be modified to an arrangement on the XZ plane shown in FIG. 8B.

  As described above, by adjusting the incident direction of the laser beam # 1 with respect to the reflecting mirror surface 18A two-dimensionally, the spots of the laser beams # 1 and # 2 on the recording sheet S can be always arranged in the Z-axis direction. it can. Therefore, as shown in FIG. 9, the scanning lines recorded on the recording medium 14 by the laser beams # 1 and # 2 can be formed as parallel straight lines over the entire scanning area, and the scanning line length is Can be the same.

  Here, as shown in FIG. 10A, when the spots of the laser beams # 1 and # 2 incident on the reflecting mirror surface 18A of the spinner mirror device 16 are projected onto the surface S ′ conjugate with the recording medium 14, this spinner. As shown in FIG. 10B, the locus of the laser beam # 1 on the conjugate plane S ′ accompanying the rotation of the mirror device 16 is that the angular velocity of the spinner mirror device 16 is ω, and the laser beam # 1 and the laser beam # 2 are used. W (distance between the position of the beam spot on the scanning surface by the laser beam # 1 and the position of the beam spot on the scanning surface by the laser beam # 2) on the scanning surface. 9)

It becomes a circle represented by. Therefore, by deflecting the laser beam # 1 in accordance with this equation and guiding it to the optical scanner 2, a plurality of scanning lines spaced apart by a fixed width W on the scanning surface are formed as shown in FIG. can do.

  Next, the configuration of the inner drum exposure apparatus according to the second embodiment will be described with reference to FIG. The inner drum exposure apparatus according to the second embodiment uses first and second semiconductor laser light sources 30A and 30B (light beam output means). That is, since the first and second semiconductor laser light sources 30A and 30B respectively emit linearly polarized light beams (laser beams) La and Lb, both the light beams La and Lb are respectively collimated lenses (collimator lenses). ) 44 and 46 are respectively parallel beams.

  The first laser beam La emitted from the first semiconductor laser light source 30A is guided to the polarization beam splitter 48 and combined with the second laser beam Lb. The combined light beams La and Lb are, similarly to the inner drum exposure apparatus of the first embodiment shown in FIG. 1 described above, a quarter-wave plate 32, a reflecting mirror 34, and an optical system on the light source side. The light is guided to the spinner mirror device 16 of the scanning optical system including the uniaxial crystal optical element 26 by the reflecting mirror 36 and the condenser lens 28. When the two semiconductor laser light sources 30A and 30B are used as light sources in this way, the laser driver 42A for the first semiconductor laser light source 30A and the laser driver 42B for the second semiconductor laser light source 30B are used as light beam output means. Are separately prepared, and the image signals separately generated by the central controller 40 are transmitted to the respective laser drivers 42A and 42B. Then, the laser drivers 42A and 42B drive and control the first semiconductor laser light source 30A and the second semiconductor laser light source 30B, respectively, and emit laser beams La and Lb modulated based on the corresponding image signals, The spinner mirror device 16 side is irradiated by the light source side optical system.

  Further, in the optical system on the light source side for the second semiconductor laser light source 30B, the second laser beam Lb emitted from the second semiconductor laser light source 30B and made into a parallel beam by the collimating lens 46 is transmitted from the spinner mirror device 16. After passing through an acousto-optic device 52X that is a light deflector that deflects in the X-axis direction and an acousto-optic device 52Y that is a light deflector that deflects the second laser beam Lb in the Y-axis direction, the polarization beam splitter 48 To be combined with the first laser beam La. The combined light beams La and Lb are converted into right circularly polarized light and left circularly polarized light, and irradiated onto the spinner mirror device 16 side by the optical system on the light source side as described above.

  The acoustooptic element 52X and the acoustooptic element 52Y, which are these light deflecting means, are controlled by the circuit shown in FIG. The circuit as the control means includes a control circuit 54 that generates a control clock signal based on a signal from an encoder (not shown) provided in the spinner mirror device 16, and a cosine wave voltage signal (X = −a · cos ωt), a sine wave signal generation circuit 56b that generates a sine wave voltage signal (Y = −a · sin ωt) according to the control clock signal, and a frequency modulation signal from the cosine wave voltage signal. A voltage-controlled oscillator 58a that generates a frequency-modulated signal from this sine wave voltage signal, and an amplifier 60a that amplifies the frequency-modulated signal from the voltage-controlled oscillator 58a and supplies it to the acoustooptic device 52X And amplifying the frequency modulation signal from the voltage controlled oscillator 58b that generates the frequency modulation signal from the sine wave signal. And an amplifier 60b that supplies the acoustooptic device 52Y.

  Next, operations and operations relating to the inner drum exposure apparatus according to the second embodiment configured as described above will be described.

  The second laser beam Lb emitted from the second semiconductor laser light source 30B (light beam output means) and converted into a parallel beam by the collimating lens 46 is deflected in the X-axis direction by the acousto-optic element 52X as light deflecting means. After that, it is deflected in the Y-axis direction by the acousto-optic element 52Y which is a light deflecting means (see FIGS. 8A and 8B). Further, the second laser beam Lb is guided to the polarization beam splitter 48 and combined with the first laser beam La. Further, the second laser beam Lb is introduced into the spinner mirror device 16 by the optical system on the light source side.

  The spinner mirror device 16 reflects and deflects the second laser beam Lb (# 1) by the reflecting mirror surface 18A that rotates about the Z axis, and guides it to the recording medium 14.

  On the other hand, the first laser beam La (# 2) emitted from the first semiconductor laser light source 30A is introduced along the rotation axis of the spinner mirror device 16, reflected and deflected by the reflecting mirror surface 18A, and guided to the recording medium 14. It is burned.

  Next, control of the second laser beam Lb (# 1) emitted from the second semiconductor laser light source 30B will be described in detail with reference to FIG.

First, based on a position signal from an encoder (not shown) provided in the spinner mirror device 16, the control circuit 54 as a control means converts the control clock signal into a cosine wave signal generation circuit 56a.
To supply. The cosine wave voltage signal (X = −a · cos) output from the cosine wave signal generation circuit 56a.
ωt) is converted into a frequency modulation signal by the voltage controlled oscillator 58a, and then supplied to the acoustooptic device 52X via the amplifier 60a. In this case, the acoustooptic device 52X deflects the second laser beam Lb (# 1) in the X-axis direction shown in FIGS. 8A and 8B based on the cosine wave voltage signal.

  Further, the control circuit 54 as the control means supplies a control clock signal to the sine wave signal generation circuit 56b. The sine wave voltage signal (Y = −a · sin ωt) output from the sine wave signal generation circuit 56b is converted into a frequency modulation signal by the voltage controlled oscillator 58b, and then supplied to the acoustooptic device 52Y via the amplifier 60b. The In this case, the acoustooptic device 52Y uses the sine wave voltage signal to convert the second laser beam Lb (# 1) modulated in the X-axis direction by the acoustooptic device 52X based on the sine wave voltage signal, as shown in FIG. Deflection is performed in the Y-axis direction shown in FIG. 8B.

  As a result, the second laser beam Lb (# 1) guided to the reflecting mirror surface 18A of the spinner mirror device 16 is synchronized with the rotation operation of the spinner mirror device 16 as shown in FIGS. 10A and 10B. A substantially circular locus is drawn on a plane S ′ orthogonal to the rotation axis 18 of the mirror device 16.

  Further, the first laser beam La (# 2) emitted from the first semiconductor laser light source 30A is guided onto the recording medium 14 without moving the position on the surface S ′ orthogonal to the rotation axis 18.

  Then, as shown in FIG. 9, the first laser beam La (# 2) and the second laser beam Lb (# 1) whose distances are controlled to be constant are guided to the recording medium 14, and the image is displayed. Is recorded. In this case, these intervals can be easily adjusted by the amplification factor set by the amplifier 60a and the amplifier 60b.

That is, as shown in FIG. 9, two parallel scanning lines having a constant interval and a constant length are formed on the recording medium 14. At the same time, the two scanning lines are respectively the first scanning lines described above.
As in the embodiment, the beam spot is substantially equally distributed in the sub-scanning direction in the sub-scanning direction by the action of the quarter-wave plate 32 and the uniaxial crystal optical element 26, and the beams are formed in a substantially rectangular shape by superimposing them in a shifted manner. The beam is split to form a spot, each beam spot of the two scanning lines has a substantially rectangular distribution and the edge portion is steep, and each beam spot shape is elongated in the sub-scanning direction (that is, the beam spot In which the longitudinal direction of the substantially rectangular distribution is along the sub-scanning direction (direction perpendicular to the main scanning direction).

  In the inner drum exposure apparatus according to the second embodiment, as described above, the exposure processing is performed by the two scanning lines that are beam-divided as described above. The ratio of halftone image (halftone area ratio characteristic) is prevented from abruptly changing so that the circumference of the recording pixel does not change at all due to the recording condition such as the number of sheets and the developing condition such as the developing degree of the automatic processor. Therefore, it is difficult to cause density fluctuation, and it is possible to quickly record so as to stably express a halftone using an FM screen. Furthermore, in the second embodiment, the number of light beams can be increased and the number of rotations of the scanning means can be set low, so that the reliability of recording accuracy by scanning can be improved.

  In the second embodiment described above, the acousto-optic element 52X and acousto-optic element 52Y, which are light deflecting means, are configured as separate bodies. It is also possible to configure the optical deflecting means so as to realize deflection in the axial and Y-axis directions. Further, instead of using an acousto-optic element, an electro-optic element may be used. It is also possible to provide three or more semiconductor laser light sources and record an image using the plurality of laser beams. Furthermore, an image can be recorded using a laser beam obtained by splitting a laser beam emitted from a semiconductor laser light source into a required number of beams by a beam splitter.

  The configuration, operation, and effects of the second embodiment other than those described above are the same as those of the first embodiment described above. Is omitted.

  In the present invention, as described above, the exposed lithographic printing plate precursor may be entirely heated between exposure and development as necessary. By such heating, an image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, when a protective layer is provided on the photosensitive layer, it may be washed with water before development.

[Development processing]
The lithographic printing plate precursor on which an image is recorded by performing exposure using the inner drum exposure apparatus described above is developed in order to remove the non-image portion. The development process may be either wet or dry. As the developer used in the wet development, an alkali developer or a developer having a pH of 2 to 10 is appropriately selected in consideration of the characteristics of the photosensitive layer of the lithographic printing plate precursor.
The processing speed in the development process, that is, the transport speed (line speed) of the lithographic printing plate precursor in the development process is preferably 1.00 m / min or more, and more preferably 1.10 m / min or more. Although there is no restriction | limiting in particular in the upper limit of a conveyance speed, From a viewpoint of stability of conveyance, it is preferable that it is 3 m / min or less.
Hereinafter, the alkali developer that can be used in the present invention will be described.

The alkali developer is not particularly limited, but for example, an alkaline developer containing an inorganic alkali salt and a surfactant and having a pH of 11.0 to 12.5 is preferably used.
The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

In the case of using silicate, developability can be achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). Can be easily adjusted. The mixing ratio (SiO ₂ / M ₂ O: molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O is preferably 0.5 to 3.0, and preferably 1.0 to 2.0. More preferred. The concentration of the silicate is preferably 1 to 10% by mass, more preferably 3 to 8% by mass, and most preferably 4 to 7% by mass with respect to the mass of the alkaline aqueous solution. When this concentration is 1% by mass or more, developability and processing capacity are not lowered, and when it is 10% by mass or less, it is difficult to form precipitates and crystals, and further, it is difficult to gel during neutralization in the waste liquid. Does not interfere with waste liquid treatment.

  In addition, an organic alkali agent may be supplementarily used for the purpose of finely adjusting the alkali concentration and assisting the solubility of the photosensitive layer. Organic alkali agents include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

  The surfactant can be used as appropriate, for example, nonionic surfactants having a polyoxyalkylene ether group, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, Nonionic surfactants such as sorbitan alkyl esters such as sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate and sorbitan trioleate, monoglyceride alkyl esters such as glycerol monostearate and glycerol monooleate; dodecylbenzenesulfonic acid Alkylbenzene sulfonates such as sodium, sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, sodium hexyl naphthalene sulfonate Anion interfaces such as alkyl naphthalene sulfonates such as sodium and sodium octyl naphthalene sulfonate, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, and sulfosuccinate esters such as sodium dilauryl sulfosuccinate Activators: Alkyl betaines such as lauryl betaine and stearyl betaine, amphoteric surfactants such as amino acids, and the like can be mentioned. Particularly preferred are nonionic surfactants having a polyoxyalkylene ether group.

As the surfactant containing a polyoxyalkylene ether group, those having the structure of the following general formula (VI) are preferably used.
R ₄₀ —O— (R ₄₁ —O) pH (VI)

In the formula, R ₄₀ has an optionally substituted alkyl group having 3 to 15 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, or a substituent. An optionally substituted heteroaromatic cyclic group having 4 to 15 carbon atoms (wherein the substituent is an alkyl group having 1 to 20 carbon atoms, a halogen atom such as Br, Cl, or I, or an aromatic hydrocarbon having 6 to 15 carbon atoms) Group, an aralkyl group having 7 to 17 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, and an acyl group having 2 to 15 carbon atoms), and R ₄₁ is C1-C1 which may have a substituent
00 represents an alkylene group (wherein, examples of the substituent include an alkyl group having 1 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 15 carbon atoms), and p represents an integer of 1 to 100.

  In the definition of the above formula (VI), specific examples of the “aromatic hydrocarbon group” include phenyl group, tolyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group and the like, and “heteroaromatic ring” Specific examples of `` group '' include furyl group, thionyl group, oxazolyl group, imidazolyl group, pyranyl group, pyridinyl group, acridinyl group, benzofuranyl group, benzothionyl group, benzopyranyl group, benzooxazolyl group, benzoimidazolyl group, etc. It is done.

In addition, the part of (R ₄₁ —O) p in the formula (VI) may be 2 or 3 groups as long as it is in the above range. Specific examples include random or block combinations of ethyleneoxy and propyleneoxy groups, ethyleneoxy and isopropyloxy groups, ethyleneoxy and butyleneoxy groups, ethyleneoxy groups and isobutylene groups, and the like. . In the present invention, the surfactant having a polyoxyalkylene ether group is used alone or in combination, and it is effective to add 1 to 30% by mass, preferably 2 to 20% by mass in the developer. If the addition amount is small, the developability is deteriorated. On the other hand, if the amount is too large, the development damage becomes strong and the printing durability of the printing plate is lowered.

Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the above formula (VI) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and polyoxyethylene stearyl ether. Polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether and polyoxyethylene naphthyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Kind.
These surfactants can be used alone or in combination. Further, the content of these surfactants in the developer is preferably in the range of 0.1 to 20% by mass in terms of active ingredients.

The alkaline developer used in the present invention preferably has a pH in the range of 10 to 12.5 at 25 ° C, more preferably in the range of pH 11 to 12.5. Since the developer in the present invention contains the surfactant, excellent developability is exhibited in the non-image area even when such a low pH alkaline developer is used. Thus, by setting the pH of the developing solution to a relatively low value, damage to the image area during development is reduced and the handling property of the developing solution is excellent.
The conductivity x of the developer is preferably 2 <x <30 mS / cm, more preferably 5 to 25 mS / cm.
Here, it is preferable to add an alkali metal salt of an organic acid, an inorganic acid, BR> alkali metal salt, or the like as a conductivity adjusting agent for adjusting the conductivity.

The developer described above can be used as a developer and developer replenisher for the exposed lithographic printing plate precursor, and can also be applied to an automatic processor. When developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored by using a replenishing solution or a fresh developing solution. This replenishment method is also preferably applied to the plate making method of the present invention.

Furthermore, in order to restore the processing capacity of the developer using an automatic developing machine, it is preferable to replenish by the method described in US Pat. No. 4,882,246. Also, JP-A-50-
Developers described in Japanese Patent Nos. 26601, 58-54341, 56-39464, 56-42860, and 57-7427 are also preferable.
According to another aspect of the development processing in the present invention, the lithographic printing plate precursor after image exposure is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10, so that the photosensitive layer in the non-exposed area is exposed. (If there is a protective layer, the protective layer is also removed), and an image can be formed on the surface of the aluminum plate support.

  The developer used here is an aqueous solution having a pH of 2 to 10. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution having the same composition as that of a generally known fountain solution, a surfactant (anionic, nonionic, An aqueous solution containing a cationic system or the like, or an aqueous solution containing a water-soluble polymer compound is preferable. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the developer is more preferably 3-8, and even more preferably 4-7.

  Anionic surfactants used include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfones Acid salts, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurine, disodium N-alkylsulfosuccinate monoamide, petroleum sulfonates, sulfate Castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate ester salt, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, fatty acid monoglyceride Sulfate salts, polyoxyethylene alkylphenyl ether sulfate salts, polyoxyethylene styryl phenyl ether sulfate salts, alkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts, polyoxyethylene alkylphenyl ether phosphate salts, styrene -Partial saponifications of maleic anhydride copolymer, partial saponifications of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  The cationic surfactant used is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Nonionic surfactants used include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts. , Fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Fatty acid ester of glycerol, fatty acid ester of pentaerythritol, sorbitol and sorbitan fat Esters, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
These nonionic surfactants may be used alone or in admixture of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

From the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more, preferably 8 or more. It is more preferable. Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.
Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
As the surfactant used in the developer, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

  Examples of the water-soluble polymer compound used in the developer include soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol And derivatives thereof, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.

Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  The developer may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). And xylene), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), and polar solvents.

  Polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether , Propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.) , (Acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene Glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  In addition to the above, the developer may contain preservatives, chelate compounds, antifoaming agents, organic acids, inorganic acids, inorganic salts, and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred.
Among them, emulsification dispersion type and solubilization can be used.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.

  The developer described above can be used as a developer and developer replenisher for the exposed negative lithographic printing plate precursor, and is preferably applied to an automatic processor described later. When developing using an automatic processor, the developing solution becomes fatigued according to the amount of processing, so the processing capability may be restored using a replenisher or a fresh developer. This replenishing method is also preferably applied to the plate making method of the lithographic printing plate precursor according to the present invention.

  The development treatment with an aqueous solution having a pH of 2 to 10 in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while transporting a lithographic printing plate precursor after image recording, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image recording set thereon while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100554, or Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows. A brush roll can be used in which the groove mold material is radially wound around a plastic or metal roll as a core without a gap.
The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene) can be used. For example, the fiber has a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm. Can be used.
Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.
Moreover, it is preferable to use two or more rotating brush rolls.

  The rotation direction of the rotating brush roll used in the present invention may be the same direction or the reverse direction with respect to the transport direction of the planographic printing plate precursor of the present invention. As described above, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the heat sensitive layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  The lithographic printing plate precursor thus developed is subjected to washing water, surface activity as described in JP-A Nos. 54-8002, 55-115045, 59-58431, etc. It is also possible to carry out a post-treatment with a rinsing solution containing an agent or the like, a desensitizing solution containing gum arabic, starch derivatives and the like. These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention.

In the plate making method of the lithographic printing plate precursor according to the present invention, the entire image can be post-heated or exposed entirely for the purpose of improving image strength and printing durability.
Very strong conditions can be used for heating after development. Usually, the heating temperature is 200 to 500 ° C. If the heating temperature after development is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

The planographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.
As plate cleaners used for removing stains on the plate during printing, conventionally known plate cleaners for PS plates are used. For example, CL-1, CL-2, CP, CN-4, CN, CG-1, PC-1, SR, IC (made by Fuji Photo Film Co., Ltd.), etc. are mentioned.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
[Examples 1 and 2, Comparative Example 1]
(Production of support)
The following surface treatment was performed using a JIS A1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched with a 26% by weight aqueous caustic soda concentration solution (including 6.5% by weight aluminum ion concentration) at a temperature of 70 ° C. to dissolve 5 g / m ^{2 of the} aluminum plate. Thereafter, it was washed with water.

  (B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

(D) An aluminum plate is etched by spraying with an aqueous solution of caustic soda 26% by weight (including aluminum ion concentration 6.5% by weight) at 35 ° C., 0.2 g / m ^{2 of the} aluminum plate is dissolved, The smut component mainly composed of aluminum hydroxide generated when electrochemical roughening was used, and the edge portion of the generated pit was dissolved to smooth the edge portion. Thereafter, it was washed with water.

  (E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(F) Anodization was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), a temperature of 33 ° C., and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. The amount of the anodized film at this time was 2.7 g / m ² .
The surface roughness Ra of the aluminum support thus obtained was 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 micrometer).

<Undercoat layer>
The following undercoat liquid was applied to a support using a bar coater so as to have a dry coating amount of 2 mg / m ² and dried at 80 ° C. for 20 seconds.

(Undercoat liquid)
Polymer (P1) 0.3g
60.0g of pure water
Methanol 939.7g

    Polymer (P1)

[Preparation of lithographic printing plate precursor 1]
A photosensitive composition (1) having the following composition was coated on the support using a bar coater, and then dried at 100 ° C. for 1 minute. The weight of the photosensitive layer after drying was 1.1 g / m ² .

(Photosensitive composition (1))
Polymerizable compound: ethylenically unsaturated bond-containing compound (A-1) 0.46 parts by mass Binder polymer (B-1) 0.51 parts by mass Sensitizing dye (D39) 0.03 parts by mass Photopolymerization initiator (C -1) (Kurokinkasei Co., Ltd.) 0.12 parts by mass ε-phthalocyanine (F-1) dispersion 0.47 parts by mass Mercapto compound (S-1) 0.09 parts by mass Fluorine-based nonionic surfactant (Megafuck F-780F,
Dainippon Ink & Chemicals, Inc.) 0.009 parts by mass N-nitrosophenylhydroxylamine aluminum salt 0.003 parts by mass (Cupelon, manufactured by Wako Pure Chemical Industries, Ltd.)
Methyl ethyl ketone 7.4 parts by mass Propylene glycol monomethyl ether 7.4 parts by mass On the photosensitive layer, a protective layer coating solution (1) having the following composition was placed on a bar so that the dry coating mass was 2.4 g / m ^2. The lithographic printing plate precursor 1 was obtained by coating with a coater and drying at 120 ° C. for 1 minute.
(Coating liquid for protective layer (1))
5.0 parts by weight of polyvinyl alcohol (PVA205, saponification degree: 88 mol%, polymerization degree: 500, manufactured by Kuraray Co., Ltd.)
Nonionic surfactant (EMALEX 710, manufactured by Nippon Emulsifier Co., Ltd.) 0.09 parts by mass Pure water 94.91 parts by mass

[Preparation of lithographic printing plate precursor 2]
The photosensitive composition (2) having the following composition was coated on the support using a bar coater, and then dried at 100 ° C. for 1 minute. The weight of the photosensitive layer after drying was 1.3 g / m ² .

(Photosensitive composition (2))
Polymerizable compound: Ethylenically unsaturated bond-containing compound (A-1) 1.5 parts by mass Binder polymer (B-2) 1.6 parts by mass Sensitizing dye (D29) 0.15 parts by mass Photopolymerization initiator (C -2) 0.12 parts by mass ε-phthalocyanine (F-1) dispersion 0.02 parts by mass Sensitization aid (G-1) 0.5 parts by mass Fluorine nonionic surfactant (Megafac F-780F,
(Manufactured by Dainippon Ink & Chemicals, Inc.) 0.02 parts by mass Methyl ethyl ketone 26.0 parts by mass Propylene glycol monomethyl ether 26.3 parts by mass On the photosensitive layer, a protective layer coating solution (2) having the following composition was prepared. A lithographic printing plate precursor 2 was obtained by applying with a bar coater such that the dry coating mass was 2.5 g / m ² and drying at 120 ° C. for 1 minute.
(Coating liquid for protective layer (2))
Polyvinyl alcohol 5.0 mass parts (degree of saponification: 98 mol%, degree of polymerization: 500)
Nonionic surfactant (EMALEX 710, manufactured by Nippon Emulsifier Co., Ltd.) 0.09 parts by mass Pure water 94.91 parts by mass

  The ethylenically unsaturated bond-containing compound (A-1), ε-phthalocyanine (F-1), photopolymerization initiator (C-1), (C) used in the photosensitive compositions (1) and (2). -2), sensitization aid (G-1), binder polymer (B-1), (B-2), and structure of mercapto compound (S-1) are shown below. Sensitizing dyes (D39) and (D29) are the compounds exemplified above as specific examples.

[Evaluation of flat mesh unevenness]
A lithographic printing plate precursor was drawn with an exposure of 90 μJ / cm ² and a resolution of 2438 dpi on a 35% flat screen on an FM screen (TAFFETA 20) manufactured by Fuji Photo Film Co., Ltd. The exposure apparatus includes a FUJIFILM Electronic Imaging Ltd. Violet semiconductor laser setter (Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW)) and a light source having the beam shape of the present invention shown in FIG. The mounted exposure apparatus (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) was used. The plate after the exposure was heated at 100 ° C. for 10 seconds using an automatic developing machine (LP1250PLX), and then the PVA protective layer was washed away with water, and subsequently developed at 28 ° C. for 20 seconds. The developer used was a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. diluted 5 times with water. The developed plate was washed in a rinse bath and then sent to a gumming bath. For the gum bath, a solution obtained by diluting gum solution FP-2W manufactured by Fuji Photo Film Co., Ltd. with water twice. The plate after gumming was discharged after hot air drying. A lithographic printing plate on which a 35% flat screen of FM screen was drawn was obtained. The area ratio of the flat screen of the obtained lithographic printing plate was measured with CC-dot 5 (manufactured by CENTURFAX Ltd.), and the maximum and minimum area difference (δdot) was calculated. δdot is preferably as small as possible, and is practically preferably 2.0% or less. If it is 3.0% or more, it is a level that causes a problem in practical use. The results are shown in Table 1.

As is apparent from Table 1, in Examples 1 and 2 by the plate making method of the present invention using the specific exposure apparatus described above, the area difference (δdot) of the flat mesh is as small as 1.0% or less, and there is no variation in the flat mesh. Less good results are obtained. On the other hand, in the plate making method of the comparative example, the area difference of the flat net is as large as 3.5%, which is a level of flat net variation that causes a practical problem.

[Examples 3 to 10 and Comparative Example 2]
(Production of support)
In order to remove rolling oil on the surface of a 0.3 mm thick aluminum plate (material: JIS1050), a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using 3 bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 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 the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Next, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. After a direct current anodized film of 2.5 g / m ² of the plate 15 wt% sulfuric acid (containing 0.5 mass% of aluminum ion) at a current density of 15A / dm ² as the electrolytic solution, washed with water and dried.
The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Next, the following undercoat liquid was bar coated so that the dry coating amount was 10 mg / m ² and then oven-dried at 80 ° C. for 10 seconds to prepare a support having an undercoat layer.

<Undercoat liquid>
・ Undercoat compound (1) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

[Preparation of lithographic printing plate precursor (3)]
A photosensitive layer coating solution (3) having the following composition was bar coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and a photosensitive layer having a dry coating amount of 1.1 g / m ² . Formed. A protective layer coating solution (3) having the following composition was applied on this using a bar so that the dry coating amount was 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds to form a protective layer. The lithographic printing plate precursor (3) was obtained.

<Photosensitive layer coating solution (3)>
・ The following binder polymer (1) (average molecular weight 80,000) 0.54 g
・ Polymerizable compound 0.40g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
・ Polymerizable compound Ethoxylated trimethylolpropane triacrylate 0.08 g
(Nippon Kayaku Co., Ltd., SR9035,
EO addition mole number 15, molecular weight 1000)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (1) 0.18 g
・ The following co-sensitizer (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, binder polymer (1) as a dispersant: 10 parts by mass,
Cyclohexanone / methoxypropyl acetate / 1-methoxy-2 as solvent
-Propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt-The following fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (3)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (molecular weight 70,000) 0.5g
Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
950g of water

[Preparation of lithographic printing plate precursor (4)]
The sensitizing dye (1), the polymerization initiator (1), and the co-sensitizer (1) in the photosensitive layer coating solution (3) are respectively the following sensitizing dye (2), polymerization initiator (2), and co-intensifier. A lithographic printing plate precursor (4) was obtained in the same manner as the preparation of the lithographic printing plate precursor (3) except that the sensitizer (2) was changed.

[Preparation of lithographic printing plate precursor (5)]
A lithographic printing plate precursor (5) was obtained in the same manner as the preparation of the lithographic printing plate precursor (3) except that the photosensitive layer coating solution (3) was changed to a photosensitive layer coating solution (4) having the following composition.

<Photosensitive layer coating solution (4)>
・ 0.2 g of the above polymerization initiator (1)
・ Sensitizing dye (1) 0.1 g
・ Binder polymer (1) (average molecular weight 80,000) 3.0 g
-Polymerizable compound 6.2g
Isocyanuric acid EO-modified diacrylate (Aronix M-215 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 0.2g
・ 0.1 g of the above fluorosurfactant (1)
・ The following microcapsule (1) dispersion 25.0 g
・ Methyl ethyl ketone 35.0g
・ 3-methoxy-2-propanol 35.0 g

(Preparation of microcapsule (1) dispersion)
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, isocyanuric acid EO-modified diacrylate (Toa Gosei Co., Ltd. Aronix M-215) 4.15 g and 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) were dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration became 20% by mass.
The average particle size was 0.25 μm.

[Preparation of lithographic printing plate precursor (6)]
Polymerization compound Aronix M-315 of photosensitive layer coating solution (3) is manufactured by PLEX6661-O (Rohm GmbH & KG, 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diaza A lithographic printing plate precursor (6) was obtained in the same manner as the lithographic printing plate precursor (3) except that it was changed to hexadecane-1,16-diyldimethacrylate).

[Preparation of lithographic printing plate precursor (7)]
A lithographic printing plate precursor (7) was obtained in the same manner as the lithographic printing plate precursor (3) except that the binder polymer (1) of the photosensitive layer coating solution (3) was changed to the following binder polymer (2).

[Preparation of lithographic printing plate precursor (8)]
A lithographic printing plate precursor (8) was obtained in the same manner as the lithographic printing plate precursor (3) except that the binder polymer (1) of the photosensitive layer coating solution (3) was changed to the binder polymer (3) shown below.

[Preparation of lithographic printing plate precursor (9)]
A lithographic printing plate precursor (9) was obtained in the same manner as the lithographic printing plate precursor (3) except that the binder polymer (1) of the photosensitive layer coating solution (3) was changed to the binder polymer (4) shown below.

[Preparation of lithographic printing plate precursor (10)]
The lithographic printing plate precursor except that the protective layer coating solution (3) is changed to a protective layer coating solution (4) having the following composition and coated using a bar so that the dry coating amount is 0.2 g / m ^2. A lithographic printing plate precursor (10) was obtained in the same manner as in the preparation of (3).

Protective layer coating solution (4)
・ The following mica dispersion (1) 13.0 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (molecular weight 70,000) 0.05 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

(Preparation of mica dispersion (1))
To 368 g of water, 32 g of synthetic mica (Somasif ME-100, manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) was added and dispersed using a homogenizer until the average particle size (laser scattering method) became 0.5 μm. A dispersion (1) was obtained.

(1) Exposure With respect to each of the above lithographic printing plate precursors (3) to (10), an exposure amount of 90 μJ / cm ² , resolution of 2438 dpi, and 35% flatness with an FM screen (TAFFETA 20) manufactured by Fuji Photo Film Co., Ltd. Draw a net.
The exposure apparatus includes a FUJIFILM Electronic Imaging Ltd Violet semiconductor laser setter (Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW)) and a Vx9600 modified light source having the beam shape of the present invention shown in FIG. The mounted exposure apparatus (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) was used.

(2) Development The exposed lithographic printing plate precursor was developed with an automatic developing processor having a structure shown in FIG. 12, using a developer (1) having the following composition. The pH of the developer was 5. The automatic developing processor is an automatic processor having two rotating brush rolls. As the rotating brush roll, the first brush roll is made of polybutylene terephthalate fiber (hair diameter: 200 μm, hair length: 17 mm). Using a brush roll with an outer diameter of 90 mm implanted with 200 mm / min in the same direction as the conveying direction (peripheral speed 0.94 m / sec at the tip of the brush), the second brush roll is made of polybutylene terephthalate Using a brush roll having an outer diameter of 60 mm in which fibers (hair diameter: 200 μm, hair length: 17 mm) were implanted, it was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip: 0.63 m / sec). . The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the developer was 10 liters.

Developer (1)
・ Water 100g
・ Benzyl alcohol 1g
・ Polyoxyethylene naphthyl ether (oxyethylene average number n = 13) 1g
・ Dioctyl sulfosuccinate sodium salt 0.5g
・ 1g gum arabic
・ Ethylene glycol 0.5g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

(3) Evaluation of flat net unevenness The area ratio of the flat net of the lithographic printing plate obtained after the development was measured with a halftone dot measuring machine CC-dot 5 (manufactured by CENTURFAX Ltd.), and the maximum and minimum area difference (Δdot). Was calculated. Δdot is preferably as small as possible, and is practically preferably 2.0% or less. If it is 3.0% or more, it is a level that causes a problem in practical use. The results are shown in Table 2.

Example 11
Example 3 except that polyoxyethylene naphthyl ether of developer (1) is changed to the following anionic surfactant and 0.1 g of antifoaming agent FS Antihome DR110N (manufactured by Dow Corning, silicone emulsion) is added. Similarly, when image exposure, development processing, and evaluation of unevenness of a flat mesh were performed, Δdot was 1.0%. The pH of the developer was 5.

Example 12
Except that the developing solution (1) was changed to the following developing solution (2), image exposure, development processing, and evaluation of unevenness of flat netting were carried out in the same manner as in Example 3. As a result, Δdot was 1.0%. The pH of the developer was 4.5.

Developer (2)
・ Water 100g
・ Sodium alkyl naphthalene sulfonate 5g
(Perox NB-L manufactured by Kao Corporation)
・ 1g gum arabic
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

As apparent from Table 2, in Examples 3 to 12 by the plate making method of the present invention using the specific exposure apparatus described above, the area difference (Δdot) of the flat mesh is as small as 1.5% or less, and there is a variation in the flat mesh. Less good results are obtained. On the other hand, in the plate making method of the comparative example, the area difference of the flat net is as large as 4.0%, which is a level of flat net variation that causes a practical problem.

It is a schematic block diagram which shows the inner drum exposure apparatus concerning 1st Embodiment. It is a schematic block diagram which takes out and shows the principal part of the spinner mirror apparatus in the inner drum exposure apparatus concerning 1st Embodiment. It is explanatory drawing which shows the effect | action of the optical element of the uniaxial crystal used for the inner drum exposure apparatus concerning 1st Embodiment. It is explanatory drawing which shows the light quantity distribution of the beam spot divided by the inner drum exposure apparatus concerning 1st Embodiment. It is explanatory drawing which shows the light quantity distribution of the beam spot shape of the Gaussian distribution generally used conventionally, in order to compare with the light quantity distribution of the beam spot divided by the inner drum exposure apparatus concerning 1st Embodiment. It is a schematic block diagram which shows the inner drum exposure apparatus concerning 2nd Embodiment. FIG. 7A, FIG. 7B, and FIG. 7C are explanatory diagrams of the principle according to the second embodiment. 8A and 8B are explanatory diagrams of the principle according to the second embodiment. It is explanatory drawing which shows the scanning line on the recording medium concerning 2nd Embodiment. FIG. 10A and FIG. 10B are explanatory views showing the trajectory of the light beam on the surface conjugate with the recording medium according to the second embodiment. It is a circuit block diagram for the drive of the acousto-optic device used with the inner drum exposure apparatus concerning 2nd Embodiment. It is explanatory drawing which shows the structure of an automatic developing processor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inner drum exposure apparatus 12 Support body 14 Recording medium 16 Spinner mirror apparatus 18 Rotating shaft 18A Reflective mirror surface 24 Holder 24A Through hole 26 Optical element 30 of uniaxial crystal Semiconductor laser light source 30A Semiconductor laser light source 30B Semiconductor laser light source 32 1/4 wavelength Plate 48 Polarizing beam splitter 52X Acousto-optic element 52Y Acousto-optic element 54 Control circuit 61 Rotating brush roll 62 Receiving roll 63 Conveying roll 64 Conveying guide plate 65 Spray pipe 66 Pipe line 67 Filter 68 Feeding plate 69 Discharge plate 70 Developer tank 71 Circulation pump version 72

Claims (15)

In the plate making method of exposing a lithographic printing plate precursor having at least a photosensitive layer on a support using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm,
The photosensitive layer comprises a photosensitive composition containing a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound, and a binder polymer,
In the inner drum exposure apparatus, the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beam spots partially overlap. Adjacent to each other in the sub-scanning direction,
A method for making a lithographic printing plate precursor, comprising: placing the lithographic printing plate precursor on the inner drum exposure device; and performing image recording by exposing the light beam spot shape. 2. The plate making method of a lithographic printing plate precursor according to claim 1, wherein an image is recorded using an FM screen during the exposure.   The lithographic printing plate precursor method according to claim 1 or 2, wherein a wet or dry development process is performed after the image recording.   The lithographic printing plate precursor method according to claim 3, wherein wet development such as alkali development or water development is performed during the development process. The plate making method of a lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the polymerization initiator is a hexaarylbiimidazole compound.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the lithographic printing plate precursor has a protective layer on the photosensitive layer. After exposing a lithographic printing plate precursor having at least a photosensitive layer on a support using an inner drum exposure apparatus equipped with a light source having an oscillation wavelength in the range of 360 nm to 450 nm, an automatic processor equipped with a rubbing member In the plate making method of a lithographic printing plate precursor, the photosensitive layer in the non-exposed area is removed by rubbing the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10.
The photosensitive layer comprises a photosensitive composition containing a sensitizing dye that absorbs light of 360 nm to 450 nm, a polymerization initiator, a polymerizable compound, and a hydrophobic binder polymer,
In the inner drum exposure apparatus, the light beam spot shape of the light beam emitted from the light source divides the light beam into an ordinary ray and an extraordinary ray in parallel with an equal amount of light, and the two beam spots partially overlap. Adjacent to each other in the sub-scanning direction,
A method for making a lithographic printing plate precursor, comprising: placing the lithographic printing plate precursor on the inner drum exposure device; and performing image recording by exposing the light beam spot shape.   8. The plate making method of a lithographic printing plate precursor according to claim 7, wherein image recording is performed using an FM screen during the exposure.   The lithographic printing plate precursor as claimed in claim 7, wherein the lithographic printing plate precursor has a protective layer on the photosensitive layer.   The lithographic printing plate precursor making method according to claim 7, wherein the hydrophobic binder polymer has an acid value of 0.3 meq / g or less. 8. The hydrophobic binder polymer is at least one selected from a (meth) acrylic copolymer having a crosslinkable group in a side chain and a polyurethane resin having a crosslinkable group in a side chain. A process for making a lithographic printing plate precursor as described in 1.   The method for making a lithographic printing plate precursor as claimed in claim 7, wherein the polymerization initiator is a hexaarylbiimidazole compound.   The plate making method of a lithographic printing plate precursor according to claim 7, wherein a part or all of the photosensitive layer constituting component is encapsulated in a microcapsule.   The lithographic printing plate precursor making method according to claim 7, wherein the rubbing member is at least two rotating brush rolls.   The plate making method of a lithographic printing plate precursor as claimed in claim 7, wherein the pH of the developer is from 3 to 8.

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