JP2004133445A - Original plate for planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To present a means of further improving the developing solution latitude and flaw-proof of an original plate for an IR photosensitive planographic printing plate for direct plate making. <P>SOLUTION: The original plate for the planographic printing plate is provided with a photosensitive layer containing a water-insoluble and alkali-soluble resin and an IR absorbent on an aluminum substrate formed by subjecting an aluminum plate to surface roughening and alkali etching treatment. The original plate for the planographic printing plate in which the coating quantity of the photosensitive layer is 0.5 to 3 g/m<SP>2</SP>and the relative standard deviation of the film thickness distribution of the photosensitive layer is ≤20% is presented. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a lithographic printing plate precursor, and more particularly to a so-called lithographic printing plate precursor for direct plate making that can be directly made from a digital signal of a computer or the like.

In recent years, laser development has been remarkable, and in particular, solid lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared are easily available in high output and small size. These lasers are very useful as an exposure light source for making a plate directly from digital data output from a computer or the like.

This lithographic printing plate material for infrared laser for direct plate making comprises, as essential components, a binder resin that is soluble in an alkaline aqueous solution and an infrared absorber that absorbs light and generates heat (hereinafter sometimes referred to as IR dye). In the unexposed area (image area), the IR dye acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by interacting with the binder resin. In the exposed area (non-image area), the IR dye The light absorbed by the light and the like is converted into heat and generates heat, whereby the interaction between the IR dye and the binder resin is weakened and dissolved in the alkaline developer, so that a lithographic printing plate having an image-like distribution is formed.
Here, in a lithographic printing plate using an aluminum support that has been roughened and formed with an anodized film, the thermal conductivity of the support is extremely higher than that of the photosensitive layer, so the vicinity of the interface between the photosensitive layer and the support. The heat generated in is diffused into the support before the image formation reaction (alkali solubilization reaction) proceeds sufficiently. As a result, in the vicinity of the interface of the photosensitive layer support, the solubility of the photosensitive layer in the developing solution becomes insufficient, and a residual film tends to occur in a portion that should originally become a non-image portion. This residual film generation is significant when the photosensitive layer coating amount is large. In order to suppress the occurrence of this residual film, it is necessary to use a highly active developer or reduce the coating amount of the photosensitive layer, but this tends to cause image omission in the portion that should originally become the image area. Become. That is, the development activity of the residual film or image loss easily occurs only by a slight change in the developer activity indicated by the conductivity at the time of development, and the development latitude is significantly narrower than that of the conventional PS plate system used conventionally. Is essentially a problem. In order to cope with this problem, a method for improving the developability of the photosensitive layer in the vicinity of the photosensitive layer support interface for the lithographic printing plate material for infrared laser and a method for suppressing the developer solubility of the unexposed photosensitive layer. Various methods have been studied, but have not yet reached a satisfactory level.

Also, if the photosensitive layer that is alkali-solubilized by heating is damaged for some reason, even the portion that originally becomes the image portion is easily dissolved in the developer. In other words, it has become a printing plate that is very easily damaged. For this reason, scratch-like image loss may occur due to slight contact such as bumping when handling the printing plate, slight rubbing on the interleaf, and finger contact with the plate surface, which is very difficult to handle. Is the current situation.

Further, in order to solve the above problem, the amount of alkali etching is 0.5 to 4 g / m ² , and the film thickness of the photosensitive layer on the convex portion of the substrate is observed by SEM. A lithographic printing plate precursor having a thickness of 2 μm has been proposed (for example, Patent Document 1), but scratch resistance and development latitude were not sufficient.
JP 2002-72458 A

An object of the present invention is to provide a lithographic printing plate precursor having a wide development latitude and in which scratch-like image omission is unlikely to occur.

As a result of intensive studies to achieve the above object, the present inventor completed the present invention.
That is, the present invention is a lithographic printing plate precursor in which a photosensitive layer containing a water-insoluble and alkali-soluble resin and an infrared absorber is provided on an aluminum support obtained by subjecting an aluminum plate to a roughening treatment and an alkali etching treatment. A lithographic printing plate precursor having a coating amount of the photosensitive layer of 0.5 to 3 g / m ² and a relative standard deviation of the film thickness distribution of the photosensitive layer of 20% or less. The coating amount of the photosensitive layer is preferably 0.7 to 1.5 g / m ² , more preferably 0.7 to 1.2 g / m ² . If the coating amount is too small, there will be a problem with printing durability, and if it is too large, the development process will be burdened.

The mechanism for improving the development latitude by defining the photosensitive layer coating amount and the coating amount distribution is estimated as follows. That is, since the aluminum support of a lithographic printing plate precursor is generally roughened and has irregularities on the surface, the film thickness of the photosensitive layer coated on the aluminum support is usually unsatisfactory. It becomes uniform. Therefore, an image omission in a portion that should originally become an image portion is likely to occur in a thin portion of the photosensitive layer, and a residual film in a portion that is supposed to be a non-image portion is likely to occur in a thick portion of the photosensitive layer. Therefore, in the present invention, it is considered that by providing the photosensitive layer so that the film thickness is uniform on the support, there are no extremely thin portions and thick portions, and image loss and residual film are less likely to occur. .
Further, the scratch resistance improvement mechanism by prescribing the photosensitive layer coating amount and the coating amount distribution is estimated as follows. That is, scratch-like image omission is likely to occur in a thin portion of the photosensitive layer on the support convex portion, and by making the photosensitive layer uniform, there is no portion where the coating amount is extremely thin, and the scratch-like image is lost. It is considered that image omission is less likely to occur.

The present inventor accurately measured the film thickness of the photosensitive layer coated on the roughened support for various samples, determined the relative standard deviation thereof, and quantified it. The inventors have found that a lithographic printing plate precursor having a film thickness and a film thickness distribution is suitable for the purpose, and have achieved the present invention.

According to the present invention, a lithographic printing plate precursor excellent in scratch resistance and development latitude can be provided by defining the film thickness distribution and the coating amount so that the film thickness of the photosensitive layer is uniform.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor of the present invention is for a lithographic printing plate in which a photosensitive layer containing a water-insoluble and alkali-soluble resin and an infrared absorber is provided on an aluminum support obtained by subjecting an aluminum plate to a surface roughening treatment and an alkali etching treatment. It is an original plate, and the coating amount of the photosensitive layer is 0.5 to 3 g / m ² , preferably 0.7 to 1.5 g / m ² , more preferably 0.7 to 1.2 g / m ² , and the film thickness of the photosensitive layer The relative standard deviation of the distribution is 20% or less.

The relative standard deviation of the film thickness distribution of the photosensitive layer of the lithographic printing plate precursor according to the present invention is not particularly limited as long as it is 20% or less, but is preferably 15% or less, and in the range of 10% or less from the stability of sensitivity over time. Is more preferable.
The method for controlling the relative standard deviation of the film thickness distribution of the photosensitive layer of the lithographic printing plate precursor according to the present invention to 20% or less is not particularly limited, but high-pressure air is blown when the photosensitive layer is dried, or Examples thereof include a method of rapidly drying such as contact with a heating roll, and a method of adjusting the concentration of the coating solution of the photosensitive layer when the photosensitive layer is applied and dried. Moreover, the method of controlling the viscosity or surface tension of a coating liquid by adjusting the solvent and various additives contained in a photosensitive layer can also be used.
Furthermore, a method of controlling the surface shape of the support by mechanical surface roughening treatment, electrochemical surface roughening treatment or etching conditions of the aluminum support can also be used.

In the present invention, FIG. 1 shows a configuration example of an apparatus for performing continuous coating and drying using a roughened aluminum web as a support.

The apparatus shown in FIG. 1 performs a coating head 2 that coats a roughened aluminum web 1 with a photosensitive solution, a first drying zone 3 that performs high-speed drying by blowing with hot air and high-pressure air, and drying with hot air. And a second drying zone 4. In the first drying zone 3, an air supply port 5 for sending hot air, a high-pressure air generating device 9 for performing high-speed drying, a heat exchanger 10, a pressure gauge 11, a high-pressure air blowing nozzle 12, and air volume adjusting dampers 18, 19 And an exhaust port 6 for discharging hot air out of the system. The second drying zone 4 is provided with an air supply port 7 for sending hot air and an exhaust port 8 for discharging the hot air out of the system. Furthermore, guide rolls 13 to 17 for conveying the aluminum web 1 are installed at appropriate positions of the apparatus.

In such an apparatus, a roughened aluminum web 1 continuously running at 5 to 150 m / min is coated with a photosensitive solution 5 to 40 ml / m ² by a coating head 2 and guided to the first drying zone 3 at a normal temperature of 50 to 50. Hot air of 150 ° C. is sent out from the air supply port 5, and drying of the web 1 proceeds. The evaporated solvent gas is accompanied by hot air and discharged out of the system through the exhaust port 6. At the stage of being dried with hot air in the vicinity of the entrance in the first drying zone 3, the coating film is usually in an undried state.

The coating film is dried very rapidly by the high-speed air blown from the high-speed blowing nozzle 12 installed at a position substantially perpendicular to the traveling direction of the web 1 at the transport position of the undried coating film.

High-pressure air generated by a high-pressure air generator 9 comprising a compressor or a high-pressure blower is heated to 50 to 200 ° C. by a heat exchanger 10 and adjusted to a desired air volume by air volume adjusting dampers 18 and 19. After supply. As a result, the high-pressure slit-shaped air having a desired temperature and wind speed is violently collided with the undried coating film, whereby the solvent can be rapidly evaporated in a very short time to form a photosensitive film (photosensitive layer). Usually, the pressure in the nozzle 12 of high-pressure air is 300 mmAq (H ₂ O) to 3 kg / cm ² , and preferably 1000 mmAq to 1 kg / cm ² . The wind speed of the blown air from the high pressure wind blowing nozzle 12 is about 20 m / s to 300 m / s. The slit interval of the high-speed air blowing nozzle 12 is about 0.1 mm to 5 mm, but is preferably in the range of 0.3 mm to 1 mm. Further, the spray angle of the high-pressure air to the aluminum web 1 is 0 ° to 90 °, but 10 ° to 60 ° is preferable. Although the number of nozzles is two in the illustrated example, it can be about 1 to 8 depending on the drying load.

In the present invention, it is preferable to use drying with a heating roll in combination with drying with high-speed air. For example, the guide roll 14 may be a heating roll. In such a case, the surface temperature of the roll can be heated to 80 to 200 ° C. by supplying a heating medium such as steam into the roll. With such a heating roll, heat energy can be given by conduction heat from the lower surface of the aluminum web 1, and the solvent can be evaporated more rapidly than in the case of a high-pressure nozzle wind alone. Therefore, it is possible to further uniform the photosensitive layer thickness distribution.

In this way, high-speed drying is performed in the first drying zone 3, a film is formed, and the film thickness distribution is determined. Thereafter, the web 1 is guided to the second drying zone 4 and heated by hot air of 100 ° C. to 150 ° C. from the air supply port 7. Thereby, the residual solvent amount remaining in a minute amount in the film is controlled in the range of 30 to 200 mg / m ² . Further, the solvent gas is discharged out of the system through the exhaust port 8.

And, a desired film thickness distribution can be achieved by these drying operations.

In the illustrated example, the hot air drying is performed in the first drying zone 3 and then the hot air drying and the high pressure air are combined. However, the first hot air drying is omitted, and the high pressure air is dried immediately after the application. It does not matter if you do.

In the present invention, it is efficient and preferable to apply and dry continuously using a coating and drying apparatus as shown in FIG. Further, it is preferable to improve the productivity of the support by roughening the support continuously by, for example, providing a roughening means upstream of the coating head 2.

[Measurement method of photosensitive layer thickness distribution]
In the present invention, the relative standard deviation of the photosensitive layer thickness distribution can be measured as follows.
A printing original plate is cut into 1 cm × 1 cm, and carbon characteristic X-ray intensity is measured using EPMA JXA8800 manufactured by JEOL without vapor deposition. Measurement conditions are stage scan method, acceleration voltage: 20 kV, probe current: about 5 × 10 ⁻⁷ A, probe diameter: 2 μm, x-direction measurement interval: 2 μm, y-direction measurement interval: 2 μm, number of measurement points: 512 × 256 points, Dwell time: 50 ms, spectral crystal: LDE1H, diffraction angle θ: 46.4 °. Relative standard deviation RSD = σ / I × 100 (%) was calculated from the average intensity I and standard deviation σ of the characteristic X-ray intensity of 512 × 256 points obtained.

Next, each main part of the lithographic printing plate precursor according to the invention will be described.
First of all, the components contained in the photosensitive layer will be described.

[Alkali-soluble resin]
Next, the alkali-soluble resin (polymer compound) contained in the photosensitive layer of the lithographic printing plate precursor according to the invention will be described.
The photosensitive layer of the lithographic printing plate precursor according to the present invention contains a water-insoluble and alkali-soluble polymer compound (hereinafter also referred to as an alkali-soluble polymer or an alkali-soluble resin as appropriate). The alkali-soluble polymer includes a homopolymer containing an acidic group in the main chain and / or side chain in the polymer, a copolymer thereof, or a mixture thereof. Therefore, the photosensitive layer according to the present invention has a property of dissolving when contacted with an alkaline developer.

The alkali-soluble polymer is not particularly limited as long as it is a conventionally known polymer, but any functional group of (1) a phenolic hydroxyl group, (2) a sulfonamide group, or (3) an active imide group is present in the molecule. It is preferable that it is a high molecular compound. For example, the following are exemplified, but not limited thereto.

(1) Examples of the polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, xylenol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol ( Any of m-, p-, and m- / p-mixing may be used. Examples thereof include novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. In addition to this, a polymer compound having a phenolic hydroxyl group in the side chain is preferably used as the polymer compound having a phenolic hydroxyl group. As a polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer comprising a low molecular compound having at least one unsaturated bond polymerizable with the phenolic hydroxyl group is homopolymerized, or other polymerizable property is added to the monomer. Examples thereof include a polymer compound obtained by copolymerizing monomers.

Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylate ester, methacrylate ester or hydroxystyrene having a phenolic hydroxyl group. Specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N- (3 -Hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p- Hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) Preferred are ethyl acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, and the like. Can be used. Such resins having a phenolic hydroxyl group may be used in combination of two or more. Furthermore, as described in U.S. Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. A condensation polymer may be used in combination.

(2) Examples of the alkali-soluble polymer compound having a sulfonamide group include a polymer compound obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the monomer with another polymerizable monomer. . The polymerizable monomer having a sulfonamide group includes one or more sulfonamide groups —NH—SO ₂ — in which at least one hydrogen atom is bonded on a nitrogen atom and one or more polymerizable unsaturated bonds in one molecule. And a polymerizable monomer comprising a low molecular weight compound. Among these, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and an unsubstituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

(3) The alkali-soluble polymer compound having an active imide group is preferably one having an active imide group in the molecule. As the polymer compound, an unsaturated bond polymerizable with an active imide group is contained in one molecule, respectively. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer composed of one or more low-molecular compounds or by copolymerizing the monomer with another polymerizable monomer.

As such a compound, specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

Furthermore, as the alkali-soluble polymer compound, a polymer obtained by polymerizing two or more of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, and the polymerizable monomer having an active imide group is used. It is preferable to use a compound or a polymer compound obtained by copolymerizing other polymerizable monomers with these two or more kinds of polymerizable monomers. When the polymerizable monomer having a phenolic hydroxyl group is copolymerized with a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imide group, the blending mass ratio of these components is 50:50 to 5: It is preferably in the range of 95, particularly preferably in the range of 40:60 to 10:90.

In the lithographic printing plate precursor according to the invention, the alkali-soluble polymer is a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, a polymerizable monomer having an active imide group, and another polymerizable monomer. In the case of the copolymer, the monomer that imparts alkali solubility is preferably contained in an amount of 10 mol% or more, more preferably 20 mol% or more.

Examples of other monomer components that can be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the following (m1) to (m12). Examples of the compound can be exemplified, but are not limited thereto.
In addition, as a copolymerization method of the alkaline water-soluble polymer compound, a conventionally known graft copolymerization method, block copolymerization method, random copolymerization method, or the like can be used.

(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

In the lithographic printing plate precursor according to the invention, the alkali-soluble polymer is a homopolymer or copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group. In the case of coalescence, those having a mass average molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferred. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (mass average molecular weight / number average molecular weight) is 1.1 to 10. .
When the alkali-soluble polymer is a resin such as phenol formaldehyde resin or cresol aldehyde resin, those having a mass average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 are preferable.

These alkali-soluble polymer compounds may be used alone or in combination of two or more, and are 30 to 99% by mass, preferably 40 to 95% by mass, particularly preferably 50%, based on the total solid content of the photosensitive layer. Used in an addition amount of ˜90% by mass.

[Infrared absorber]
The infrared absorbing agent (hereinafter also referred to as infrared absorbing dye) contained in the photosensitive layer of the lithographic printing plate precursor according to the present invention is not particularly limited as long as it is a dye that absorbs infrared light and generates heat. Instead, various dyes known as infrared absorbing dyes can be used.

As the infrared absorbing dye according to the present invention, commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by Organic Synthetic Chemistry Association, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb infrared light or near infrared light are particularly preferred because they are suitable for use in lasers that emit infrared light or near infrared light.

Examples of dyes that absorb such infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Examples thereof include squarylium dyes described in JP-A-58-112792, and cyanine dyes described in British Patent 434,875.

Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salts, trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59 -84248, 59-84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes, U.S. Pat. No. 4,283,475 The pentamethine thiopyrylium salt described in No. 5 and the pyrylium compound disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 Commercially available products, Eporin Co. Epolight III-178, Epolight III-130, Epolight III-125 and the like are particularly preferably used.
Another particularly preferable example of the dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

In the lithographic printing plate precursor according to the invention, the infrared absorber is 0.01 to 50% by mass, preferably 0.1 to 50% by mass, particularly preferably 0.1 to 30% by mass, based on the total solid content of the photosensitive layer. Can be added at a ratio of

[Solubility-inhibiting compounds]
The lithographic printing plate precursor according to the invention can contain various inhibitors in the photosensitive layer for the purpose of enhancing its inhibition (solubility inhibition).
Although it does not specifically limit as this inhibitor, A quaternary ammonium salt, a polyethyleneglycol type compound, etc. are mentioned.

The quaternary ammonium salt is not particularly limited, and examples thereof include tetraalkylammonium salts, trialkylarylammonium salts, dialkyldiarylammonium salts, alkyltriarylammonium salts, tetraarylammonium salts, cyclic ammonium salts, and bicyclic ammonium salts. It is done.
Specifically, tetrabutylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide, tetraoctylammonium bromide, tetralaurylammonium bromide, tetraphenylammonium bromide, tetranaphthylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide , Tetrastearyl ammonium bromide, lauryl trimethyl ammonium bromide, stearyl trimethyl ammonium bromide, behenyl trimethyl ammonium bromide, lauryl triethyl ammonium bromide, phenyl trimethyl ammonium bromide, 3-trifluoromethylphenyl trimethyl ammonium bromide, benzyl trimethyl ammonium bromide De, dibenzyl dimethyl ammonium bromide, distearyl dimethyl ammonium bromide, tristearyl methyl ammonium bromide, benzyl triethyl ammonium bromide, hydroxyphenyl trimethyl ammonium bromide, N- methyl pyridinium bromide, and the like.

The addition amount of the quaternary ammonium salt is preferably 0.1 to 50%, more preferably 1 to 30% in terms of solid content with respect to the total solid content of the photosensitive layer.

Although it does not specifically limit as a polyethyleneglycol compound, The thing of the following structure is mentioned.

^{R 1 - {- O- (R} 3 -O-) m -R 2} n

(R ¹ is a polyhydric alcohol residue or polyhydric phenol residue, R ² is a hydrogen atom, an alkyl group, alkenyl group, alkynyl group, alkyloyl group, aryl group which may have a substituent having 1 to 25 carbon atoms. Or an aryloyl group, R ³ represents an alkylene residue which may have a substituent, m is an average of 10 or more, and n is an integer of 1 to 4.

Examples of polyethylene glycol compounds having the above structure include polyethylene glycols, polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers, polyethylene glycol alkyl aryl ethers, Polypropylene glycol alkyl aryl ethers, polyethylene glycol glycerin esters, polypropylene glycol glycerin esters, polyethylene sorbitol esters, polypropylene glycol sorbitol esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, polyethylene glycolated ethylene Diamines, polypropylene glycolated ethylenediamines, polyethylene glycolated diethylenetriamine, and polypropylene glycol diethylenetriamines.

Specific examples thereof include polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 10000, polyethylene glycol 20000, polyethylene glycol 5000, polyethylene glycol 100000, polyethylene glycol 200000, polyethylene glycol 500000, polypropylene glycol 1500, polypropylene glycol. 3000, polypropylene glycol 4000, polyethylene glycol methyl ether, polyethylene glycol ethyl ether, polyethylene glycol phenyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol diphenyl ether , Polyethylene glycol lauryl ether, polyethylene glycol dilauryl ether, polyethylene glycol nonyl ether, polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol distearyl ether, polyethylene glycol behenyl ether, polyethylene glycol dibehenyl ether, polypropylene glycol methyl ether, polypropylene Glycol ethyl ether, polypropylene glycol phenyl ether, polypropylene glycol dimethyl ether, polypropylene glycol diethyl ether, polypropylene glycol diphenyl ether, polypropylene glycol lauryl ether, polypropylene glycol dilauryl ether, Ripropylene glycol nonyl ether, polyethylene glycol acetyl ester, polyethylene glycol diacetyl ester, polyethylene glycol benzoate ester, polyethylene glycol lauryl ester, polyethylene glycol dilauryl ester, polyethylene glycol nonyl acid ester, polyethylene glycol cetylate ester, polyethylene glycol stearoyl ester, Polyethylene glycol distearoyl ester, polyethylene glycol behenate ester, polyethylene glycol dibehenate ester, polypropylene glycol acetyl ester, polypropylene glycol diacetyl ester, polypropylene glycol benzoate ester, polypropylene glycol dibenzoate ester, Polypropylene glycol laurate, polypropylene glycol dilaurate, polypropylene glycol nonyl ester, polyethylene glycol glycerol ether, polypropylene glycol glycerol ether, polyethylene glycol sorbitol ether, polypropylene glycol sorbitol ether, polyethylene glycolated ethylenediamine, polypropylene glycolated ethylenediamine, polyethylene Examples include glycolated diethylenetriamine, polypropylene glycolated diethylenetriamine, and polyethylene glycolated pentamethylenehexamine.

The addition amount of the polyethylene glycol compound is preferably 0.1 to 50%, more preferably 1 to 30% in terms of solid content with respect to the total solid content of the photosensitive layer.

Further, when the above-described measures for improving the inhibition (solubility inhibition) are performed, the sensitivity is lowered. In this case, it is effective to add a lactone compound. This lactone compound is considered to be that when the developer penetrates into the exposed area, the developer and the lactone compound react to generate a new carboxylic acid compound, contributing to dissolution of the exposed area and improving sensitivity.
Although it does not specifically limit as a lactone compound, The compound represented by the following general formula (LI) and general formula (L-II) is mentioned.

In general formula (LI) and general formula (L-II), X ¹ , X ² , X ³ and X ⁴ are ring constituent atoms or atomic groups, which may be the same or different, and are independent of each other. And may have a substituent, and at least one of X ¹ , X ² and X ^{3 in} the general formula (LI) and X ¹ , X ² , X ³ and X in the general formula (L-II) ^At least one of ⁴ has an electron-withdrawing substituent or a substituent substituted with an electron-withdrawing group.
The constituent atoms or atomic groups of the ring represented by X ¹ , X ² , X ³ and X ⁴ are nonmetallic atoms having two single bonds for forming a ring or atomic groups containing the nonmetallic atoms.
A preferred nonmetallic atom or nonmetallic atomic group is an atom or atomic group selected from a methylene group, a sulfinyl group, a carbonyl group, a thiocarbonyl group, a sulfonyl group, a sulfur atom, an oxygen atom, and a selenium atom, and more preferably, It is an atomic group selected from a methylene group, a carbonyl group and a sulfonyl group.

At least one of X ¹ , X ² and X ^{3 in} the general formula (LI) or at least one of X ¹ , X ² , X ³ and X ^{4 in} the general formula (L-II) is an electron withdrawing group Have In the present specification, an electron-withdrawing substituent refers to a group in which Hammett's substituent constant σp takes a positive value. Regarding the Hammett substituent constant, Journal of Medicinal Chemistry, 1973, Vol. 16, No. 11, 1207-1216, etc. can be referred to. Examples of electron-withdrawing groups in which Hammett's substituent constant σp takes a positive valence include halogen atoms (fluorine atoms (σp value: 0.06), chlorine atoms (σp value: 0.23), bromine atoms (σp value). : 0.23), iodine atom (σp value: 0.18)), trihaloalkyl group (tribromomethyl (σp value: 0.29), trichloromethyl (σp value: 0.33), trifluoromethyl (σp) Value: 0.54)), cyano group (σp value: 0.66), nitro group (σp value: 0.78), aliphatic / aryl or heterocyclic sulfonyl group (for example, methanesulfonyl (σp value: 0. 72)), aliphatic / aryl or heterocyclic acyl groups (for example, acetyl (σp value: 0.50), benzoyl (σp value: 0.43)), alkynyl groups (for example, C≡CH (σp value: 0)) .23)), Aliphatic Ali Or a heterocyclic oxycarbonyl group (for example, methoxycarbonyl (σp value: 0.45), phenoxycarbonyl (σp value: 0.44)), carbamoyl group (σp value: 0.36), sulfamoyl group (σp value: 0.57), sulfoxide groups, heterocyclic groups, oxo groups, phosphoryl groups and the like.

Preferred electron withdrawing groups are amide groups, azo groups, nitro groups, fluoroalkyl groups having 1 to 5 carbon atoms, nitrile groups, alkoxycarbonyl groups having 1 to 5 carbon atoms, acyl groups having 1 to 5 carbon atoms, and carbon numbers. An alkylsulfonyl group having 1 to 9 carbon atoms, an arylsulfonyl group having 6 to 9 carbon atoms, an alkylsulfinyl group having 1 to 9 carbon atoms, an arylsulfinyl group having 6 to 9 carbon atoms, an arylcarbonyl group having 6 to 9 carbon atoms, and thiocarbonyl A group selected from a group, a fluorine-containing alkyl group having 1 to 9 carbon atoms, a fluorine-containing aryl group having 6 to 9 carbon atoms, a fluorine-containing allyl group having 3 to 9 carbon atoms, an oxo group, and a halogen element.
More preferably, a nitro group, a fluoroalkyl group having 1 to 5 carbon atoms, a nitrile group, an alkoxycarbonyl group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, an arylsulfonyl group having 6 to 9 carbon atoms, carbon It is a group selected from an arylcarbonyl group of formulas 9 to 9, an oxo group and a halogen element.
Specific examples of the compounds represented by formulas (LI) and (L-II) are shown below, but the present invention is not limited to these compounds.

The addition amount of the compounds represented by the general formula (LI) and the general formula (L-II) is preferably 0.1 to 50% in terms of solid content with respect to the total solid content of the photosensitive layer, preferably 1 to 30 % Is more preferable.
These lactone compounds may be used alone or in combination. Two or more compounds of the general formula (LI) or two or more compounds of the general formula (L-II) may be used in an arbitrary ratio within the above range.

The lithographic printing plate precursor according to the present invention may further contain a substance that is thermally decomposable and substantially reduces the solubility of the alkali-soluble resin in a state where it is not thermally decomposed. This is preferable from the viewpoint of further expanding the difference.
The “substance that is thermally decomposable and substantially reduces the solubility of the alkali-soluble resin in a state where it is not thermally decomposed” is not particularly limited, and examples thereof include various onium salts and quinonediazide compounds. In particular, an onium salt is preferable from the viewpoint of thermal decomposability.

Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like. Suitable onium salts for use in the present invention include, for example, SI Schlesinger, Photogr. Sci. Eng., 18, 387 (1974), TS Bal et al, Polymer, 21, 423 (1980), No. 158230, US Pat. Nos. 4,069,055, 4,069,056, Re 27,992, and ammonium salts described in the specification of Japanese Patent Application No. 3-140140 DC Necker et al, Macromolecules, 17, 2468 (1984), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. No. 4,069,055, ibid. , 069,056, JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), Chem. &Amp; Eng. News, Nov. 28, p31 (1988), European Patent No. 104, 143, U.S. Pat. Nos. 339,049 and 41. 201, JP-A-2-150848, JP-A-2-296514, iodonium salts, JV Crivello et al, Polymer J. 17, 73 (1985), JV Crivello et al. J. Org. Chem., 43 , 3055 (1978), WR Watt et al, J. Polymer Sci., Polymer Chem. Ed., 22, 1789 (1984), JV Crivello et al, Polymer Bull., 14, 279 (1985), JV Crivello et al. , Macromorecules, 14 (5), 1141 (1981), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979), European Patent No. 370,693, 3,902, 114, 233,567, 297,443, 297,442, U.S. Pat.Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,734,444, 2,833,827, German Patent No. , 904, 626, 3,604, 580, 3,604, 581, JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), JV Crivello etal, J. Selenonium salts described in Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), arsonium salts described in CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988). Etc.
In the lithographic printing plate precursor according to the invention, a diazonium salt is particularly preferred. Particularly suitable diazonium salts include those described in JP-A-5-158230.

The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid. The amount of the substance added is preferably 0.1 to 50% by mass, more preferably 0.1 to 30% by mass, and particularly preferably 0.3 to 30% by mass.

Suitable o-quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the photosensitive layer by both the effect of losing the ability to suppress dissolution of the alkali-soluble resin by thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339-352 of “Light-Sensitive Systems” by John Coley (John Wiley &amp; Sons. Inc.) can be used, but in particular they were reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. O-quinonediazide sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-174741, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, No. 3,573,917, No. 3,674,495, No. 3,785,825, British Patent No. 1,227,602, No. 1,251,345, No. 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like. The addition amount of the o-quinonediazide compound used in the present invention is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, particularly preferably 10 to 30% by mass, based on the total solid content of the photosensitive layer. It is. These compounds can be used alone, but may be used as a mixture of several kinds.
From the viewpoint of degradability, the thermally decomposable substance is more preferably an onium salt.
By using this highly thermally decomposable onium salt, it is considered that the decomposition of the thermally decomposable substance in the exposed area is further promoted and the discrimination in the unexposed area of the exposed area is improved.

The lithographic printing plate precursor according to the present invention is provided with a photosensitive layer containing the alkali-soluble resin and the infrared absorber as essential components on a support. These photosensitive layers are composed of two or more layers. (For the sake of convenience, the case of two layers consisting of an upper layer and a lower layer will be described below).
In this case, the alkali-soluble resin constituting the upper layer and the lower layer can be the alkali-soluble resin described above, but the upper layer has a lower solubility in alkali than the lower layer. Is preferred.
The infrared absorber may be an infrared absorber different in each layer, or an infrared absorber composed of a plurality of compounds may be used in each layer. The amount to be contained is 0.01 to 50% by mass, preferably 0.1 to 50% by mass, and particularly preferably 0.1% to 50% by mass, based on the total solid content of the layer to be added, as described above, when used in any layer. It can add in the ratio of 0.1-30 mass%. When adding to a several layer, it is preferable to add so that the total of addition amount may become the said range.

In the state of being thermally decomposable and not thermally decomposable, the substance that substantially reduces the solubility of the alkali-soluble resin may partially decompose over time. Although it is effective to contain it in the side layer, it may be any layer or both layers. The amount to be contained is as described above. When adding to a several layer, it is preferable to add so that the total of addition amount may become the said range.
In the case of a multilayer structure, the lactone compound is effective to be contained in the upper layer, but it may be any layer or both layers.

[Other ingredients]
In forming the photosensitive layer, in addition to the essential components described above, various additives may be added as necessary as long as the effects of the present invention are not impaired. Below, the example of an additive is given and demonstrated.

For example, in order to enhance the discrimination between the image portion and the non-image portion (discrimination) and to enhance the resistance to scratches on the surface, carbon as described in JP-A-2000-187318 is used. It is preferable to use a polymer having a polymerization component of a (meth) acrylate monomer having 2 or 3 perfluoroalkyl groups of 3 to 20 in number. Such a compound may be contained in either the upper layer or the lower layer in the case of the multilayer, but it is more effective to contain it in the upper layer.
As addition amount, the ratio for which it occupies in a layer material is 0.1-10 mass%, More preferably, it is 0.5-5 mass%.

In the photosensitive layer of the lithographic printing plate precursor according to the invention, a compound that lowers the surface static friction coefficient may be added for the purpose of imparting resistance to scratches. Specific examples include esters of long-chain alkyl carboxylic acids as used in US Pat. No. 6,117,913. In the case of a multilayer structure, such a compound may be contained in either the lower layer or the upper layer, but it is more effective that it is contained in the upper layer.
The amount of addition in the material forming the layer is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass.

Moreover, you may contain the compound which has a low molecular-weight acidic group as needed. Examples of acidic groups include sulfonic acid, carboxylic acid, and phosphoric acid groups. Of these, compounds having a sulfonic acid group are preferred. Specific examples include aromatic sulfonic acids such as p-toluenesulfonic acid and naphthalenesulfonic acid, and aliphatic sulfonic acids.
In the case of a multilayer, such a compound may be contained in either the lower layer or the upper layer. The amount of addition is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass in the material forming the layer. If it exceeds 5%, the solubility of each layer in the developer increases, which is not preferable.

In the present invention, various dissolution inhibitors may be included for the purpose of adjusting the solubility. As the dissolution inhibitor, a disulfone compound or a sulfone compound as disclosed in JP-A-11-119418 is preferably used, and as a specific example, 4,4′-bishydroxyphenylsulfone is preferably used.
In the case of a multilayer, such a compound may be contained in either the lower layer or the upper layer. The preferred amount of addition is 0.05 to 20% by mass, more preferably 0.5 to 10% by mass, in the respective materials constituting the layer.

Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, cis-1,2,3,6-endooxy-tetrahydro described in US Pat. No. 4,115,128. Phthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 ″ -Trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids, and the like described in Japanese Laid-Open Patent Application No. 60-88942 and Japanese Patent Laid-Open No. 2-96755. p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfuric acid, fluorine Nylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2 -Dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. The ratio which occupies in the material which comprises the layer of said cyclic acid anhydride, phenols, and organic acids is 0.05- 20 mass% is preferable, More preferably, it is 0.1-15 mass%, Most preferably, it is 0.1-10 mass%.

Further, in order to broaden the processing stability with respect to the developing conditions, the photosensitive layer is provided with a nonionic surfactant as described in JP-A-62-251740 or JP-A-3-208514, Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane compounds as described in EP950517, and JP-A-11-288093. Such a fluorine-containing monomer copolymer can be added.
These can be used in one or both of the cases where the photosensitive layer has a multilayer structure.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and N-tetradecyl-N, N- Examples include betaine type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).

As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. Polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany can be mentioned.
The proportion of the nonionic surfactant and amphoteric surfactant in the coating liquid material is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

Further, a printing-out agent for obtaining a visible image immediately after heating by exposure and a dye or pigment as an image coloring agent can be added to the photosensitive layer.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644, and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. 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 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the printing plate material in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the printing plate material.
These can be used in one or both of the cases where the photosensitive layer has a multilayer structure.

Furthermore, a plasticizer is added to the printing plate material of the present invention, if necessary, in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

In the present specification, the lower layer indicates a layer close to the support of the layer provided in a multilayer structure on the support. Therefore, it includes that the lower layer of the photosensitive layer is a lower layer. In addition, a layer having no image recording function is provided between the photosensitive layer and the support, and this is sometimes referred to as a lower layer. In the former case, when there is no possibility of misunderstanding, the upper layer of the photosensitive layer is simply referred to as a photosensitive layer, and the lower layer is sometimes referred to as a lower layer. The latter lower layer can contain the above-described components as constituents of the photosensitive layer, except that the infrared absorber does not need to be contained, and the content thereof is also relative to the constituent solid components with respect to the photosensitive layer. It can be contained in the above-described content range as an addition amount. However, from the viewpoint of setting the solubility of the lower layer higher than that of the upper layer, the addition amount of the solubility-inhibiting compound, the solubility-accelerating compound, and the compound having the effect of improving the development sensitivity is adjusted or newly added.

The lithographic printing plate precursor according to the present invention can be formed by dissolving the above components in a solvent and coating the solution on a suitable support. The composition of the solvent for the photosensitive layer and the lower layer can be selected according to each component. The photosensitive layer and the lower layer can be formed by dissolving each component separately in a solvent and sequentially applying the solution on a support.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.

After applying the lower layer, when applying a photosensitive layer adjacent to it, if a solvent capable of dissolving the lower layer alkali-soluble polymer is used as its application solvent, mixing at the layer interface cannot be ignored, in extreme cases, There is a case where a single layer is formed instead of a multilayer. Thus, when mixing occurs at the interface between two adjacent layers, or when they are mixed with each other and behave like a uniform layer, the effect of having two layers may be impaired, which is not preferable. For this reason, the solvent used for coating the photosensitive layer is preferably a poor solvent for the alkali-soluble polymer contained in the lower layer.
The concentration of the above components (total solid content including additives) in the solvent when applying each layer is preferably 1 to 50% by mass.

In the case where the photosensitive layer has a multilayer structure, the coating amount (solid content) of the upper layer and the lower layer varies depending on the use, but the upper layer is 0.05 to 1.0 g / m ² , it is preferred layer is 0.3 to 3.0 g / m ^2. If the upper layer is less than 0.05 g / m ^2, the image forming property is lowered, sensitivity exceeds 1.0 g / m ² comes out may be reduced. It is preferable that the sum of two layers of the a 0.5 to 3.0 g / m ^2, film properties is reduced and the amount of coating is less than ^{0.5g / m 2, 3.0g / m} 2 If it exceeds, the sensitivity tends to decrease. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the upper and lower layers decrease.

Various methods can be used as a method for coating the lower layer and the photosensitive layer on the support, for example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, Examples thereof include roll coating.

In the photosensitive layer of the present invention, a surfactant for improving the coating property, for example, a fluorine-based surfactant described in JP-A No. 62-170950 can be added. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, based on the total solid content of the layer to be added.

After the lower layer is coated on the support and after the photosensitive layer is coated thereon, drying is performed. As a drying method, a known general method is used. For example, a convection heating method in which hot air is blown onto a coated support and drying is performed, and radiant heating is performed by radiant heat from heating plates disposed above and below the support described in JP-A-60-149871 In this method, a heat medium is conducted through the roller described in JP-A-60-21334 and JP-A-60-62778, and the support is brought into contact with the roller and dried by heat conduction from the roller surface. A heat heating method or the like can be used.
Among the above methods, convection drying by blowing hot air is preferable. On the other hand, from the viewpoint of controlling the moisture content in the photosensitive layer, the moisture content of the hot air is preferably 0.007 Kg / Kg or less, more preferably 0.05 Kg / Kg or less.

Regarding the developability of the lithographic printing plate precursor, if these drying conditions are severe, the conductivity of the developer capable of forming an image will be high (developability will be low), and if it is moderate, the image can be formed. The conductivity of the developer tends to be low (developability is high). Selection of desired drying conditions is performed by adjusting conditions such as the blowing temperature, the blowing amount, the blowing direction, and the temperature and material of the contact heat medium.
It is preferable that the residual solvent in the lower layer immediately before coating of the photosensitive layer is small. Preferably, it is 80 mg / m ² or less, more preferably 60 mg / m ² or less.

[Aluminum support]
<Aluminum plate (rolled aluminum)>
The aluminum plate used in the lithographic printing plate precursor according to the present invention is a metal whose main component is dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic film or paper on which aluminum or an aluminum alloy is laminated or vapor-deposited can also be used. Furthermore, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 can also be used.

In the following description, various substrates made of aluminum or an aluminum alloy listed above are collectively used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the content of the foreign elements in the alloy is 10% by mass or less. It is.

In the present invention, it is preferable to use a pure aluminum plate. However, since completely pure aluminum is difficult to manufacture in terms of refining technology, it may contain a slightly different element. Thus, the composition of the aluminum plate used in the present invention is not specified, but conventionally known and used materials such as JIS A1050, JIS A1100, JIS A3005, JIS A3004, internationally registered alloy 3103A, etc. An aluminum alloy plate can be used as appropriate. Further, the aluminum plate may be manufactured by either a continuous casting method or a DC casting method, and an aluminum plate in which DC casting method intermediate annealing or soaking treatment is omitted can also be used. In the final rolling, it is possible to use an aluminum plate provided with irregularities by lamination rolling or transfer. The thickness of the aluminum plate used in the present invention is usually about 0.1 mm to 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's desire.

The aluminum support used in the lithographic printing plate of the present invention is obtained by subjecting the above aluminum plate to a surface roughening treatment, an alkali etching treatment and an anodizing treatment. Various processes other than the treatment, the alkali etching treatment, and the anodizing treatment may be included.

<Roughening treatment (graining treatment)>
The aluminum plate is grained to a more preferable shape. Examples of the graining method include mechanical graining, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, electrochemical graining (electrochemical roughening) in which electrochemical graining is carried out in hydrochloric acid electrolyte or nitric acid electrolyte, and the aluminum brush is ground with a metal wire. Mechanical graining methods such as a ball grain method in which the aluminum surface is grained with an abrasive and a brush grain method in which the surface is grained with a nylon brush and an abrasive can be used. These graining methods can be used alone or in combination.

Among them, the method for producing a grainy surface suitably used in the present invention is an electrochemical method in which graining is chemically performed in a hydrochloric acid electrolyte or a nitric acid electrolyte. A preferable current density is 50 to 400 C / dm ² in terms of electricity at the time of anode. More specifically, for example, in an electrolytic solution containing 0.1 to 50% by mass of hydrochloric acid or nitric acid, under conditions of a temperature of 20 to 100 ° C., a time of 1 second to 30 minutes, and a current density of 100 to 400 C / dm ² . This is done using direct current or alternating current. Electrochemical roughening is suitable for improving the adhesion between the photosensitive layer and the substrate because it is easy to impart fine irregularities to the surface.

  By this roughening, crater-like or honeycomb-like pits having an average diameter of about 0.5 to 20 μm can be generated on the surface of the aluminum plate at an area ratio of 30 to 100%. The provided pits have the effect of improving the resistance to soiling of the non-image area of the printing plate and the printing durability. In the electrochemical treatment, the amount of electricity necessary to provide sufficient pits on the surface, that is, the product of the current and the time during which the current is applied is an important condition in electrochemical roughening. From the viewpoint of energy saving, it is desirable that sufficient pits can be formed with a smaller amount of electricity. The surface roughness after the roughening treatment is such that the arithmetic average roughness (Ra) measured with a cut-off value of 0.8 mm and an evaluation length of 3.0 mm in accordance with JIS B0601-1994 is 0.2-0. It is preferably 5 μm.

<Alkaline etching treatment>
The grained aluminum plate is chemically etched with alkali.
The alkali agent suitably used in the present invention is not particularly limited, and examples thereof include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, and lithium hydroxide.
The conditions for the alkali etching treatment are not particularly limited as long as the dissolution amount of Al is 0.5 to 4 g / m ² , but the alkali concentration is preferably 1 to 50% by mass. More preferably, it is -30 mass%, and it is preferable that the temperature of an alkali is 20-100 degreeC, and it is more preferable that it is 30-50 degreeC.

After the alkali etching treatment, pickling is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. In particular, as a method for removing smut after the electrochemical surface roughening treatment, it is preferable to use 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739. The method of making it contact is mentioned.

<Anodizing treatment>
The aluminum plate treated as described above is preferably further subjected to an anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. Specifically, when direct current or alternating current is applied to an aluminum plate in an aqueous solution or non-aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., alone or in combination of two or more. An anodized film can be formed on the surface of the aluminum plate.

At this time, at least a component normally contained in an Al alloy plate, an electrode, tap water, ground water, or the like may be contained in the electrolytic solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cations such as ammonium ion; anions such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10000 ppm It may be contained at a concentration of about.

The conditions for the anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is −5 to 70 ° C., and the current density is 0.8. 5 to 60 a / dm ^2, voltage 1 to 100 V, is suitably an electrolysis time of 10 to 200 seconds.
Among these anodizing treatments, the method of anodizing at a high current density in a sulfuric acid electrolyte solution described in British Patent 1,412,768 is particularly preferable.

In the present invention, the amount of the anodized film is preferably 1 to 10 g / m ² . The amount of anodized film, more preferably from 1.5~7g / m ^2, particularly preferably from 2-5 g / m ^2.

<Alkali metal silicate treatment>
The aluminum support on which the anodic oxide film obtained by the treatment as described above is formed is dipped using an aqueous solution of an alkali metal silicate as necessary. The treatment conditions are not particularly limited. For example, the treatment conditions are immersed in an aqueous solution having a concentration of 0.01 to 5.0% by mass at a temperature of 5 to 40 ° C. for 1 to 60 seconds, and then washed with running water. A more preferable immersion treatment temperature is 10 to 40 ° C., and a more preferable immersion time is 2 to 20 seconds.

Examples of the alkali metal silicate used in the present invention include sodium silicate, potassium silicate, and lithium silicate.
The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVB) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of Group 4 (Group IVB) metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium oxalate potassium, titanium sulfate, titanium tetraiodide, zirconium chloride oxide, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVB) metal salts are used alone or in combination of two or more.

The amount of Si adsorbed by the alkali metal silicate treatment is measured by a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² .
By this alkali metal silicate treatment, an effect of improving the solubility resistance of the aluminum support surface to the alkaline developer is obtained, and the dissolution of the aluminum component into the developer is suppressed. Can be reduced.

In the lithographic printing plate precursor according to the invention, at least the above-described photosensitive layer is provided on a support, and an undercoat layer can be provided between the support and the photosensitive layer as necessary.
Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, —OR ^14. , -COOR ¹⁵ , -CONHR ¹⁶ , -COR ¹⁷ or -CN, or R ¹² and R ¹³ may be bonded to form a ring, and R ^{14 to} R ¹⁷ are each independently an alkyl group or Represents an aryl group, X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl. Represents a group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

This undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, then washed with water or the like and dried to provide an undercoat layer. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.
The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² .

[Plate making / printing]
The lithographic printing plate precursor produced as described above is shipped, transported, and stored in the form of products that are stacked and packaged with the slip sheets inserted between the printing plate precursors. This is a general aspect. As a typical mode for plate making and printing, an autoloader secures a pair of overlapped paper and original plate to the autoloader, conveys them, and attaches and fixes them at the position where plate making is performed. Although it is a mode in which the paper is removed, the present invention is not limited to this. The position where plate making is performed is on the printing press in the direct printing method.
The original from which the interleaving paper has been removed is subjected to image exposure and development processing.
As an actinic ray light source used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and it is not necessarily a scanning method, that is, a surface exposure method may be used. Scanning exposure using a laser or semiconductor laser is preferred. The emission wavelength is preferably 760 to 1080 nm.

The developer that can be applied to the lithographic printing plate precursor according to the present invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used as the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer called an “silicate developer” having an pH of 12 or higher does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

In the former, the aqueous solution of alkali metal silicate is a ratio of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]. ) And the density, the developability can be adjusted. For example, as disclosed in JP-A-54-62004, the SiO ₂ / Na ₂ O molar ratio is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4 mass% is disclosed in JP-B-57-7427. As described, [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and SiO ₂ The developer is based on gram atoms of all alkali metals present in the developer. A manner containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

In addition, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of the lithographic printing plate material of the present invention. When the lithographic printing plate material is developed using this developer, the surface of the photosensitive layer is not deteriorated and the inking property of the photosensitive layer can be maintained in a good state. In addition, the lithographic printing plate material generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. In addition, the effect of improving discrimination between the image portion and the non-image portion (discrimination) is remarkable. This is presumed to be because the contact (penetration) with the developer, which is important for maintaining the distinguishability and film physical properties in the present invention, becomes mild, and the difference between the exposed and unexposed areas is likely to occur.

The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other, or a glycoside in which a reducing group and a non-saccharide are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

Examples of the trehalose type oligosaccharide include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable in that they have a buffering action in an appropriate pH region and are inexpensive.

These non-reducing sugars may be used alone or in combination of two or more. The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass. If the content is less than 0.1% by mass, a sufficient buffering effect tends to be not obtained, and if it exceeds 30% by mass, it is difficult to achieve high concentration and the cost tends to increase.

In addition, examples of the base used in combination with the non-reducing sugar include conventionally known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.

The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable.
In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

Further, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in Ionization Constants of Organic Acidsin Aqueous Solution published by Pergmon Press.

Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol, aldehydes such as pyridine-2-aldehyde and pyridine-4-aldehyde, and salicylic acid 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m-, Compounds having a phenolic hydroxyl group such as p-cresol and resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine, oxaxin Nucleic acid-related substances such as Chin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

In the developer and replenisher, various surfactants and organic solvents are added as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. it can. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acids, antifoaming agents, Softeners and the like can be added.

The image forming material developed using the developer and the replenisher is post-processed with a desensitizing solution containing rinse water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As the post-treatment when the image forming material is used as a printing plate, these treatments can be used in various combinations.

In recent years, automatic developing machines for printing have been widely used in the plate making and printing industries in order to streamline and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

In the printing plate precursor according to the present invention, image portions unnecessary for the planographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, film edge traces of the original film). Etc.), the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, when a lithographic printing plate having a higher printing durability is desired, a burning treatment is performed. Applied. In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The The heating temperature and time in this case depend on the type of components forming the image, but are preferably in the range of 180 to 300 ° C. and in the range of 1 to 20 minutes.

The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.
(Examples 1-5 and Comparative Examples 1-3)
[Production of substrate]
<Aluminum plate>
Si: 0.08 mass%, Fe: 0.28 mass%, Cu: 0.025 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.015% by mass, and the balance is prepared using Al and an inevitable impurity aluminum alloy. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing using a continuous annealing machine at 500 degreeC, it finished by cold rolling to 0.24 mm in thickness, and obtained the aluminum plate of JIS1050 material. After making this aluminum plate width 1030mm, it used for the surface treatment shown below.

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

(A) Mechanical surface roughening treatment Using an apparatus as shown in FIG. 2, a slurry of slurry (pumice, average particle size 30 μm) and water (specific gravity 1.12) was used as an abrasive slurry to make aluminum. While being supplied to the surface of the plate, a mechanical surface roughening treatment was performed by a rotating roller-like nylon brush. In FIG. 2, 101 is an aluminum plate, 102 and 104 are roller brushes, 103 is a polishing slurry, and 105, 106, 107 and 108 are support rollers. The average particle size of the abrasive was 30 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.48 mm. The nylon brush was planted so as to be dense by making holes in a stainless steel tube having a diameter of 300 mm (the brush hair density was 450 / cm ² ). Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass and a temperature of 70 ° C. ² dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 9 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 3, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 4 was used.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 197 C / dm ^{2 as} 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.
Then, water washing by spraying was performed.

(E) Alkali etching treatment An aluminum plate is subjected to an etching treatment by spraying at 40 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.5 g / m ² , The smut component mainly composed of aluminum hydroxide generated when the electrochemical surface roughening treatment was performed using the alternating current in the previous stage was removed. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with an aqueous solution of sulfuric acid having a temperature of 30 ° C. and a concentration of 300 g / l (containing 4.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 3, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 4 was used.
The current density was 25A / dm ² at the peak current, the quantity of electricity of the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode.
Then, water washing by spraying was performed.

(H) Alkaline etching treatment The aluminum plate was subjected to an etching treatment at 35 ° C. using an aqueous solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved at 0.20 g / m ² . The smut component mainly composed of aluminum hydroxide generated when the electrochemical surface roughening treatment was performed using the alternating current in the previous stage was removed. Then, water washing by spraying was performed.

(I) Desmutting treatment Desmutting treatment was carried out by spraying with a 300 g / l aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5 mass% of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(J) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having a structure shown in FIG. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

The substrate obtained above was dried, and further treated with a 2.5% by weight aqueous solution of sodium silicate at 30 ° C. for 10 seconds, the following undercoat solution was applied, and the coating film was dried at 80 ° C. for 15 seconds to obtain a substrate. The coating amount of the coating film after drying was 15 mg / m ² .

[Undercoat liquid]
・ The following polymer compound 0.3g
・ Methanol 100 g
・ Water 1 g

[Formation of photosensitive layer]
A photosensitive layer 1 having the following formulation was provided on the substrate prepared as described above.
Examples 1 and 2 and comparative example 1 (photosensitive layer 1)
After coating the photosensitive layer formulation 1 coating solution of the following composition, the photosensitive layer coating film is dried in the drying zone shown in FIG. 1, and about 10 seconds after coating, 3000 mmAq of high-pressure air is applied in an undried state by a slit nozzle. The lithographic printing plate precursor of Example 1 was obtained. The drying time in the first drying zone 3 is 15 seconds as a whole, the hot air temperature in the case of drying with hot air is 80 ° C. (wind speed 5 m / s), and the temperature of the high-pressure air is 60 ° C. (wind speed 200 m / s). It was. The drying time in the second drying zone 4 was 20 seconds as a whole, and the hot air temperature was 120 ° C. The coating amount was 1 g / m ² . When the film thickness distribution of the photosensitive layer was measured by the above method, the relative standard deviation was 15%.

Samples were prepared in the same manner except that drying was performed by blowing high-pressure air, and drying was performed by adding heat drying by changing the guide roll 14 to a heating roll. Drying with a heating roll at this time was performed at 100 ° C. for 1.2 seconds together with drying by blowing high-pressure air to obtain a lithographic printing plate precursor of Example 2.
The coating amount was 1 g / m ² and the relative standard deviation of the photosensitive layer thickness distribution was 10%.
A lithographic printing original plate of Comparative Example 1 was obtained in the same manner as in Example 1 except that the drying was performed with hot air drying at 100 ° C. for 2 minutes (hot air speed of 2 m / s).
The coating amount was 1 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 30%.

(Photosensitive layer formulation 1 coating solution)
・ N- (4-Aminosulfonylphenyl) methacrylamide / 2.370 g
Acrylonitrile / methyl methacrylate (35/30/35: weight average molecular weight 50000)
・ M, p-cresol novolak 0.474 g
(PR54046, manufactured by Sumitomo Deyures)
・ Cyanine dye A (the following structure) 0.109 g
・ 4,4′-bis (hydroxyphenyl) sulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.190 g
・ P-Toluenesulfonic acid 0.008 g
・ 0.100 g of counter anion of ethyl violet
What was changed to 6-hydroxynaphthalenesulfonic acid ・ Dimystyryl 3,3′-thiodipropionate 0.030 g
・ 3,3′-thiodipropionic acid di-n-dodecyl 0.030 g
-Fluorosurfactant (Megafac F-176, 0.035 g
Dainippon Ink Industry Co., Ltd.)
・ Fluorine surfactant (Defenser MCF-312 0.035 g
Dainippon Ink Industry Co., Ltd.)
・ Methyl ethyl ketone 26.6 g
1-methoxy-2-propanol 13.6 g
・ Γ-butyrolactone 13.8 g

Example 3 and Comparative Example 2 (photosensitive layer 2)
The photosensitive layer prescription 2 coating solution having the following composition was coated with a wire bar so that the coating amount was 1.8 g / m ² , and then dried in the same manner as in Example 2 to obtain a lithographic printing plate precursor in Example 3. It was.
The coating amount was 1.3 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 9%.

Also, a lithographic printing original plate of Comparative Example 2 was obtained in the same manner as in Example 3 except that the drying was performed by hot air drying at 100 ° C. for 2 minutes (hot air speed 2 m / s).
The coating amount was 1.3 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 25%.

(Photosensitive layer prescription 2 coating solution)
・ M, p-cresol novolak 1.000 g
(PR54020, manufactured by Sumitomo Deyures)
・ Copolymer 1 below 0.100 g
・ Cyanine dye A (the above structure) 0.100 g
・ 4,4′-bis (hydroxyphenyl) sulfone 0.050 g
・ Tetrahydrophthalic anhydride 0.050 g
・ P-Toluenesulfonic acid 0.002 g
・ 0.020 g of counter anion of ethyl violet
Changed to 6-hydroxynaphthalenesulfonic acid, dimystyryl 3,3′-thiodipropionate 0.010 g
・ 3,3′-thiodipropionic acid di-n-dodecyl 0.010 g
・ Fluorine surfactant (Megafac F-176, 0.015 g
Dainippon Ink Industry Co., Ltd.)
・ Fluorine surfactant (Defenser MCF-312 0.035 g
Dainippon Ink Industry Co., Ltd.)
・ Methyl ethyl ketone 12.0 g

(Synthesis of copolymer 1)
In a 20 ml three-necked flask equipped with a stirrer, a condenser tube and a dropping funnel, 6.39 g (0.045 mol) of n-propyl methacrylate, 1.29 g (0.015 mol) of methacrylic acid and 20 g of 1-methoxy-2-propanol The mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of “V-601” (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 2 hours under a nitrogen stream while maintaining at 70 ° C. To this reaction mixture, 6.39 g (0.045 mol) of n-propyl methacrylate, 1.29 g (0.015 mol) of methacrylic acid, 20 g of 1-methoxy-2-propanol and 0.15 g of “V-601” The mixture was added dropwise via a dropping funnel over 2 hours. After completion of dropping, the resulting mixture was further stirred at 90 ° C. for 2 hours. After completion of the reaction, 40 g of methanol was added to the mixture, cooled, and the resulting mixture was poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was removed by filtration and dried. 15 g of copolymer 1 was obtained as a white solid.
It was 53,000 when the weight average molecular weight (polystyrene standard) of this copolymer 1 was measured by the gel permeation chromatography.

Example 4 and Comparative Example 3 (photosensitive layer 3)
After applying a lower layer coating solution having the following composition, it was dried in the same manner as in Example 2. Next, a photosensitive layer formulation 3 coating solution having the following composition was applied onto the lower layer and dried in the same manner as in Example 2 to obtain a lithographic printing plate precursor in Example 4.
The coating amount was 1.2 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 10%.

Further, a lithographic printing original plate of Comparative Example 3 was obtained in the same manner as in Example 4 except that the lower layer coating and the image recording formulation 3 coating were dried at 100 ° C. for 2 minutes with hot air drying (hot air speed 2 m / s). It was.
The coating amount was 1.2 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 25%.

(Lower layer coating solution)
・ N- (4-Aminosulfophenyl) methacrylamide / 2.133 g
Acrylonitrile / methyl methacrylate (36/34/30: weight average molecular weight 5000) binder cyanine dye A (above structure) 0.109 g
・ 4,4′-Bizhydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.190 g
・ P-Toluenesulfonic acid 0.008 g
・ 0.100 g of counter anion of ethyl violet
Changed to 6-hydroxynaphthalenesulfonic acid 3-methoxy-4-diazophenylamine 0.03 g
Hexafluorophosphate (thermally decomposable compound)
・ Fluorosurfactant (Megafac F176, 0.035 g
Dainippon Ink Industry Co., Ltd.)
・ Methyl ethyl ketone 26.6 g
1-methoxy-2-propanol 13.6 g
・ Γ-butyrolactone 13.8 g

(Photosensitive layer prescription 3 coating solution)
・ M, p-cresol novolak 0.348 g
(PR54046, manufactured by Sumitomo Deyures)
・ Cyanine dye A (the above structure) 0.0192 g
・ Tetraethylammonium bromide 0.030 g
・ Fluorosurfactant (Megafac F176, 0.035 g
Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6 g
1-methoxy-2-propanol 13.6 g

Example 5
The lithographic printing plate of Example 5 was prepared in the same manner as in Comparative Example 3 except that the alkali etching treatment (e) in the surface treatment step of the support was carried out at 65 ° C. and the aluminum plate was dissolved at 3.0 g / m ^2. The original version was obtained.
The coating amount was 1.2 g / m ² , and the relative standard deviation of the photosensitive layer thickness distribution was 15%.

[Evaluation of lithographic printing plate precursor]
Each sample of the obtained printing plate precursor was evaluated for scratch resistance and development latitude. The results are listed in the following table.
As a developer used in each evaluation test, a developer DT-1 manufactured by Fuji Photo Film Co., Ltd. was used for those having photosensitive layers 1 and 3, and an alkaline developer having the following composition was used for those having photosensitive layer 2. A was used.

<Alkali developer A composition>
・ SiO ₂ · K ₂ O (K ₂ O / SiO ₂ = 1/1 (molar ratio)) 4.0% by mass
・ Citric acid 0.5% by mass
・ Polyethylene glycol lauryl ether 0.6% by mass
(Weight average molecular weight 1,000)
・ Water 50.0 mass%

[Scratch resistance test]
The obtained lithographic printing plate precursor was subjected to scratching by applying a load to sapphire (1.0 mm) using a scratch tester manufactured by HEIDON, and then developing solution (diluted, DT-1 had an electric conductivity of 45 mS / The developer A was developed with a conductivity of 75 mS / cm), and a load at which scratches were visible was displayed. The larger the value, the better the scratch resistance.

[Development latitude]
The obtained lithographic printing plate precursor was drawn into an image with a Trend setter manufactured by Creo at an exposure energy of 90 mJ / cm ² .
The initial conductivity of each developer was measured and then developed, and the image density of the unexposed area (image area) was measured with a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth). Next, the electric conductivity of the developer was measured when an image area having an image density of 0.06 or less from this image density was formed. When the conductivity at this time is the conductivity after use, the larger the difference between the conductivity after use and the initial conductivity, the wider the width of the developer that can be used. It is highly liquid and excellent. The numerical values shown in the table as the development latitude, for example, 37-55 means that the initial conductivity was 37 mS / cm and the conductivity after use was 55 mS / cm.

From the above table, it is understood that the lithographic printing plate precursors (Examples 1 to 5) of the present invention in which the film thickness distribution of the photosensitive layer is equal to or less than a specific value are excellent in scratch resistance and development latitude.

One structural example of the apparatus which performs continuous application | coating drying is shown. It is a side view which shows the concept of the process of the brush graining used for the mechanical roughening process in preparation of the support body for lithographic printing plates of this invention. It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of the support body for lithographic printing plates of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in preparation of the support body for lithographic printing plates of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum web 2 Coating head 3 1st drying zone 4 2nd drying zone 5 Air supply port 6 Exhaust port 7 Air supply port 8 Exhaust port 9 High pressure wind generator 10 Heat exchanger 11 Pressure gauge 12 High pressure wind blowing nozzle 13,14 , 15, 16, 17 Guide rolls 18, 19 Air flow adjusting damper 101 Aluminum plate 102, 104 Roller brush 103 Polishing slurry liquid 105, 106, 107, 108 Support roller 211 Aluminum plate 212 Radial drum roller 213a, 213b Main electrode 214 Electrolysis Treatment liquid 215 Electrolyte supply port 216 Slit 217 Electrolyte passage 218 Auxiliary anode 219a, 219b Thyristor 220 AC power source 221 Main electrolysis tank 222 Auxiliary anode tank 410 Anodizing apparatus 412 Power supply tank 414 Electrolysis treatment tank 416 Aluminum Plates 418, 426 Electrolyte 420 Feed electrode 422, 428 Roller 424 Nip roller 430 Electrode electrode 432 Tank wall 434 DC power supply

Claims (1)

On an aluminum support obtained by subjecting an aluminum plate to at least roughening treatment and alkali etching treatment, a photosensitive layer containing a water-insoluble and alkali-soluble resin and an infrared absorber is provided, and the coating amount of the photosensitive layer is 0.5 to 3 g. A lithographic printing plate precursor having a relative standard deviation of 20% or less of / m ² and a film thickness distribution of the photosensitive layer.

Images