JP2006091838A - Image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording method and a lithographic printing method in which both of high sensitivity and safety under white light are achieved and high picture quality with preferable fine line reproducibility can be obtained. <P>SOLUTION: The image recording method for a lithographic printing plate comprises imagewise exposure of a lithographic printing plate precursor at an imaging time per pixel of ≤1 msec using laser light having the emission wavelength of from 250 nm to 420 nm, wherein the lithographic printing plate precursor has an image recording layer which contains (A) a polymerization initiator and (B) a polymerizable compound and which is photosensitive at a wavelength of from 250 nm to 420 nm, on a supporting body having an anodized film with sealed micropores on the surface. The lithographic printing method uses the above recording method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image recording method and a lithographic printing method in the printing field.

  In recent years, in the field of lithographic printing, computer-to-plate technology has been developed in which lithographic printing plate precursors are directly exposed to laser on the basis of digital data such as computers without using a lithographic film. A lithographic printing plate of the type has been developed.

However, the conventional high-sensitivity laser recording lithographic printing plate is fogged when exposed to the most commonly used Ar (488, 514.5 nm) or FD-YAG (532 nm) laser inner drum plate setter on the market. There was a problem that it was likely to occur. That is, for example, when a negative type plate is used as a light-sensitive material, when a solid image is exposed on one side of the plate, the opposite side (about 140 to 220 ° when the opposite side is 180 ° with respect to the light source) In addition, there is a problem in that fogging of thinly developed defects and thick halftone dots occur, and improvement has been desired.

  In addition, high-sensitivity printing plates for conventional laser plate making compatible with Ar laser and FD-YAG laser can be removed from cardboard packaging, loaded into plate setter cassettes, and sometimes manually inserted into plate setters. In that case, it was necessary to work under a dark red light. In contrast, ordinary diazo printing plates can be handled easily under yellow light or under UV-cut white light, and the safety light suitability for high-sensitivity laser recording lithographic printing plates is greatly improved from the market in terms of workability. It was a request.

  On the other hand, in Patent Document 1, a lithographic printing plate comprising at least (A) an aluminum support and (B) a laser-sensitive recording layer is sequentially applied to a semiconductor laser beam in the ultraviolet to visible light region (360 to 450 nm). A plate making method of a lithographic printing plate is described, wherein exposure is performed with the used inner drum type plate setter. Further, it is described that according to this plate making method, it is possible to handle under a yellow light, and fog does not occur even in exposure with an inner drum type plate setter.

On the other hand, in the plate making process of the conventional lithographic printing plate precursor, a step of dissolving and removing unnecessary portions of the image recording layer with a developer or the like is necessary after exposure. In recent years, such additional wet processing is performed. One of the problems is to make the processing unnecessary or simplified.
As one of the simple plate making methods that respond to this, for example, an exposed plate mounted on a printing machine using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in printing ink and / or fountain solution A method called on-press development has been proposed in which printing ink and / or dampening water is supplied to remove unexposed portions of the image recording layer to obtain a lithographic printing plate.

However, when an image recording method using light in the ultraviolet to visible region is used for an unprocessed printing plate that does not require development processing with such a developer, the image recording layer is not fixed, and is exposed to room light after exposure. Because it has photosensitivity, it must be completely shielded from light after the lithographic printing plate precursor is taken out of the package until development on the machine is completed, or it must be handled in a safelight environment. . In other cases, for example, if the film is handled under self-lighting after exposure, unnecessary portions of the image recording layer may be fogged and remain, which may cause printing stains. Therefore, conventionally, it has been necessary to make the environment of a safe light up to a printing press work that does not require a safe light, and there has been a problem in printing work such as color adjustment. Therefore, there is a demand for an unprocessed printing plate system that can work under white light.
JP 2000-35673 A

  The present invention meets the above needs. That is, an object of the present invention is to provide an image recording method and a lithographic printing method that achieve both high sensitivity and white light safety and can obtain high image quality with good fine line reproducibility.

  1. An image recording containing (A) a polymerization initiator and (B) a polymerizable compound on a support having an anodized film with micropores sealed on the surface, and having photosensitivity in the wavelength range of 250 nm to 420 nm. An image recording method for a lithographic printing plate, wherein a lithographic printing plate precursor having a layer is exposed imagewise using a laser beam having an oscillation wavelength in the range of 250 nm to 420 nm for 1 pixel drawing time of 1 millisecond or less.

  2. 2. The image recording method as described in 1 above, wherein the laser light wavelength is any one selected from 405 nm, 375 nm, 365 nm, 355 nm and 266 nm.

  3. 2. The image recording method according to 1 above, wherein the exposure is performed using an optical system comprising a DMD or GLV modulation element and a semiconductor laser having a wavelength of 405 nm or 375 nm.

  4). 2. The image recording method according to 1 above, wherein the laser light wavelength is any one selected from 365 nm, 355 nm, and 266 nm, and exposure is performed by an inner drum system.

  5. The image recording method according to any one of claims 1 to 4, wherein the image recording layer further contains (C) a binder polymer.

  6). Printing on the exposed lithographic printing plate precursor obtained by the image recording method according to any one of 1 to 5 above after performing on-press development by supplying printing ink and / or dampening water. Including lithographic printing methods.

  7). A lithographic printing plate precursor having an image recording layer containing (A) a polymerization initiator and (B) a polymerizable compound and having a photosensitivity in a wavelength range of 250 nm to 420 nm on a support, in a wavelength range of 250 nm to 420 nm. A method for making a lithographic printing plate, comprising exposing a pixel drawing time of 1 millisecond or less using a laser beam that emits the light and developing with a developer.

  8). 8. The plate making method of a lithographic printing plate as described in 7 above, wherein the support has an anodized film having micropores sealed on its surface.

  9. 9. The plate making method of a lithographic printing plate as described in 7 or 8 above, wherein the developer is a non-alkaline developer having a pH of 10 or less.

  10. The plate making method of a lithographic printing plate as described in any one of 7 to 9 above, wherein the image recording layer further contains (C) a binder polymer.

  11. (C) The plate making method of a lithographic printing plate as described in 10 above, wherein the binder polymer does not contain an acid group.

  Although the mechanism of action of the present invention is not clear, it is estimated as follows. That is, the light source conventionally used for image recording is Ar (488, 514.5 nm), FD-YAG (532 nm) laser, metal halide lamp, etc., and imagewise exposure is performed with light in the range of 300 to 500 nm. The original plate has photosensitivity in that range, and there is a large overlap with room light that has a main light emission band in the visible region, and the light irradiation intensity is low to medium illuminance, which is comparable to room light. Since exposure is performed with high intensity, the reaction occurs in the same manner, and unnecessary image formation with respect to room light has been a problem.

  On the other hand, by shifting the absorption maximum of the photosensitive wavelength to the short wavelength side, the overlap with the emission spectrum of the white fluorescent lamp used for room light is reduced, and even when the image forming sensitivity of the recording material is sufficiently high, It is possible to prevent image formation by irradiation with a fluorescent lamp (FIGS. 1 and 2). That is, by setting the wavelength region to 250 nm to 420 nm, it is possible to minimize the overlap with room light, and it is possible to suppress unnecessary image formation due to room light irradiation.

In addition, when performing exposure recording on a radical polymerization type plate material, the optical power required for film formation varies greatly depending on the rate of the amount of oxygen flowing into the film. This can be expressed phenomenologically as follows.
In general, the amount of radicals N generated is proportional to the exposure energy J to be irradiated.
J = c1 · N (c1 is a proportional constant)
Radicals generated by irradiation light are captured by oxygen flowing into the film. This trapped amount No is proportional to the inflowing oxygen amount q per unit time and the elapsed time t from the start of exposure.
No = c2, q, t (c2 is a proportional constant)
From this, the exposure energy Jo which does not participate in the polymerization even if radicals are generated is expressed as follows.
Jo = c1, c2, q, t
Therefore, the exposure energy J required for image formation requires an irradiation energy higher than Jo.

On the other hand, if the amount of radicals generated after exposure for a short time is larger than the amount of oxygen flowing in, the polymerization is easily completed in a short time, and the irradiation energy Jth is determined regardless of the amount of oxygen flowing in. .
When this relationship is schematically represented by the time t (sec) to be irradiated on the horizontal axis and the irradiation energy J on the vertical axis, the relationship is as shown in FIG. Therefore, in the case of surface exposure in the order of minutes as in the prior art, high irradiation energy is required. On the other hand, if irradiation can be performed in the Jth time region, an image can be formed with low irradiation energy.
In the present invention, an exposure condition (for example, by a high-power UV laser) in which an irradiation time region is 1 millisecond (msec) or less, a radical generation amount is sufficiently large, and a polymerization rate is increased with respect to a radical polymerization type plate material. It has been found that there is a region that becomes the above-mentioned Jth when high illumination exposure) or a material is combined.
Therefore, by setting the irradiation time of one pixel to 1 millisecond or less when forming an image on a plate, it is possible to reduce the irradiation energy applied to the desired image formation, and the illumination is performed at a low illuminance for several minutes or more. Since the fog in a bright room (under white light) does not occur without high irradiation energy, good white light safety can be obtained.
Furthermore, by using a support having an anodized film with micropores sealed on the surface, the components of the image recording layer are prevented from entering the micropores, and the on-machine developability is improved. It is estimated that the performance is further improved.

  According to the present invention, it is possible to provide an image recording method and a lithographic printing method in which high sensitivity and white light safety are compatible, and high image quality with good fine line reproducibility can be obtained.

  Hereinafter, the exposure method, the lithographic printing method, and the lithographic printing plate precursor used for the image recording method of the present invention will be sequentially described in detail.

[Exposure method]
As the scanning exposure method for the lithographic printing plate precursor according to the present invention, a known method can be used without limitation. The wavelength of the light source used in the present invention is 250 nm to 420 nm. Specifically, as a gas laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He -Cd laser (325 nm, 1 mW to 100 mW), solid laser, 1064 nm oscillation mode-locked solid laser such as YAG, YVO _4, etc. (266 nm, 20 to 100 mW), single frequency oscillation semiconductor laser (DBR type semiconductor laser) : Wavelength 800 to 840 nm) double wave (400 to 420 nm, 5 to 30 mW), combination of waveguide wavelength conversion element and AlGaAs, InGaAs semiconductor (380 nm to 400 nm, 5 mW to 100 mW), waveguide wavelength conversion element AlGaInP, Al aAs semiconductor combinations (300nm~350nm, 5mW~100mW), AlGaInN ( 350nm~470nm, 5mW~200mW), other, N ₂ laser as a pulse laser (337 nm, pulse 0.1~10mJ), XeF (351nm, pulse 10 ˜250 mJ), a third harmonic (355 nm, 1-4 W) of a 1064 nm oscillation mode-locked solid-state laser such as YAG, YVO ₄ , and the like.

  In particular, a suitable laser among these is an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 375 nm or 405 nm, 5 to 100 mW), in terms of cost and high light intensity capable of increasing the polymerization rate and production. This is a 355 nm laser with high output in terms of the characteristics, and a 266 nm laser that has the smallest emission spectrum overlap of the white fluorescent lamp in terms of wavelength suitability and can be highly sensitive.

  In addition, the scanning exposure type lithographic printing plate exposure apparatus includes an inner drum (inner surface drum) method, an outer drum (outer surface drum method), and a flat bed method as the exposure mechanism, and the inner drum method is preferable in terms of quality and cost. In view of productivity, the external drum system is preferable.

  FIG. 4 is a conceptual diagram showing a cylindrical inner surface scanning type light beam scanning apparatus according to an embodiment of the present invention. In this figure, reference numeral 1 denotes a UV laser as a light beam output means.

The UV laser beam Lo is intensity-modulated by the electro-optic modulation element 2 in accordance with the image signal, and the beam diameter is enlarged and changed in the lenses L1 and L2 constituting the beam expander. The beam L ₀ is guided into the drum D along the central axis of the drum (cylinder) D by the half mirror 3 and the mirror 4. On the central axis of the drum D, a condenser lens L3 and a spinner SP that form a scanning optical system are provided.

The spinner SP has a reflection surface of about 45 ° with respect to the central axis (rotation axis) and is rotated at a high speed by a motor. A rotary encoder EN is attached to this motor, and the rotation angle (θ = ωt) of the spinner SP is detected. That is, the pulse signal p output at every predetermined rotation angle and the reference position signal _po indicating the reference position of one rotation are output. The beam guided to the spinner SP is focused on the inner peripheral surface of the drum D or the recording sheet S through the beam expander EX and the condenser lens L3 on the rotation axis.

  The optical power of the modulated laser beam can be calibrated by measuring the laser beam branched by the half mirror 3 with the photodetector 5.

  In the image recording apparatus, the condensing lens L3 and the spinner SP are moved at a constant speed in the sub-scanning direction along the central axis of the drum by a moving means (not shown) while the condensing beam is scanned at high speed by the spinner. Thus, the recording medium mounted on the inner peripheral surface of the drum D is two-dimensionally scanned and exposed by the exposure light emitted from the UV laser 1, and an image corresponding to the image data is recorded.

  FIG. 5 is a structural conceptual diagram of an outer drum system which is an embodiment of the image recording apparatus of the present invention. Here, FIGS. 9A and 9B are a plan view and a side view of the image recording apparatus 10 of the present embodiment, respectively. The image recording apparatus 10 modulates the light emitted from the illumination light source by the spatial light modulation element array according to the image data, and uses the modulated exposure light to form an image according to the image data on the recording medium. For recording, an exposure head 12 and a drum 14 are provided.

  The exposure head 12 generates exposure light modulated according to image data, and includes a broad area array laser diode (hereinafter referred to as BALD) 16 that is an illumination light source, a cylindrical lens 18, a collimating lens 20, a λ / 2 plate 22, a ferroelectric liquid crystal shutter array 24, which is a spatial light modulator array, a λ / 2 plate 26, an analyzer 28, and two lenses 30, 32 of a variable magnification imaging optical system, It has.

  The illumination light source may be an LD array in which individual semiconductor laser chips are arranged in a line as disclosed in JP-A-2003-158332. The laser light emitted from the laser array 16 is converged in the vertical direction in FIG. 5B by the cylindrical lens 18, and converted into parallel light in the vertical direction in FIG. 5A by the subsequent collimating lens 20. 5 (b) converges in the vertical direction and enters the λ / 2 plate 22.

  Subsequently, the polarization state of the laser light is rotated by 45 ° in the direction perpendicular to the traveling direction by the λ / 2 plate 22, and the laser light is modulated by the ferroelectric liquid crystal shutter array 24 in accordance with the image data. The At this time, the polarization state of the laser light transmitted through the ferroelectric liquid crystal shutter array 24 is rotated by 90 ° by the ferroelectric liquid crystal shutter array 24, and further, the polarization state of light by the λ / 2 plate 26 is 45 °. It is rotated and incident on the analyzer 28.

  The analyzer 28 allows only laser light whose light polarization state has been rotated to a predetermined angle, and blocks other laser light. The laser beam that has passed through the analyzer 28 is imaged at a predetermined magnification on the recording medium mounted on the drum 14 by the two lenses 30 and 32 of the variable magnification imaging optical system.

  When recording an image on a recording medium, the exposure head 12 is moved at a predetermined constant speed in the sub-scanning direction (the axial direction of the drum 14) while emitting exposure light modulated according to the image data.

  The drum 14 is a support for the recording medium. When an image is recorded on the recording medium, the recording medium is mounted on the outer peripheral surface of the drum 14, and the drum 14 is rotated at a predetermined constant speed in a predetermined direction (opposite to the main scanning direction).

In the image recording apparatus 10, exposure is performed by moving means of the exposure head 12 (not shown) while rotating the drum 14 at a predetermined constant speed in a direction opposite to the main scanning direction by rotating means of the drum 14 (not shown). By moving the head 12 in the sub-scanning direction at a predetermined constant speed, the recording medium mounted on the outer peripheral surface of the drum 14 is scanned and exposed two-dimensionally by the exposure light emitted from the exposure head 12 and imaged. An image corresponding to the data is recorded.

  Note that the SLM is not limited to the ferroelectric liquid crystal shutter array 24. For example, conventionally known transmission type and reflection type SLMs such as GLV (grating light valve) and DMD (digital micromirror device) are used. Is possible. The use of the drum 14 is not limited, and a flat plate may be used as a support for the recording medium.

  In the embodiment shown in FIG. 5, a ferroelectric liquid crystal shutter array 24 that performs line modulation is used as the spatial light modulation element array, and the exposure head 12 and the drum 14 are moved relative to each other, so that the recording material is 2 Dimensionally scanning exposure. However, the present invention is not limited to this, and as the spatial light modulation element array, for example, an element capable of surface modulation is used, and exposure light is enlarged / reduced at a predetermined magnification, and batch surface exposure is performed without scanning the recording material. It is also possible to do.

As the outer drum system, a multi-channel exposure system using an optical system composed of a combination of a spatial modulation element, such as a DMD modulation element or a GLV modulation element, and a 375 nm or 405 nm semiconductor laser is advantageous for high productivity and cost reduction. It is preferable.
An inner drum system using a laser beam having a wavelength selected from 365 nm, 355 nm, and 266 nm is preferable because it is advantageous for high-speed exposure and cost reduction.
Note that an optical system used with a DMD modulation element is described in JP-A No. 2004-012899, and an optical system using a GLV modulation element is described in JP-A Nos. 2000-168136 and 2001-162866. Has been.

  The one-pixel drawing time is preferably as short as possible in order to minimize the competitive reaction with oxygen, but is preferably 1 millisecond or less, more preferably 500 μsec or less, and most preferably 100 μsec or less. When the time is longer than 1 millisecond, polymerization inhibition due to oxygen increases and image formation deteriorates.

[Lithographic printing method]
In the lithographic printing method of the present invention, as described above, the lithographic printing plate precursor of the present invention is imagewise exposed and then developed, or an oil-based ink and a water-based ink are used without any development processing steps. Supply ingredients and print.

<Development processing>
There is no particular limitation on the developer used when developing with a developer, but a binder polymer described later contained in the image recording layer is an acid group such as a carboxyl group, a sulfone group, or a phosphate group. When it contains, the conventionally well-known alkaline aqueous solution can be used conveniently. For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium Examples include inorganic alkaline agents such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. In addition, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolan, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used.

These alkali agents are used alone or in combination of two or more. Among the above-mentioned alkaline aqueous solutions, a developing solution that exhibits the effect of the present invention is an aqueous solution containing alkali metal silicate and having a pH of 12 or more. The aqueous solution of alkali metal silicate depends on the ratio and the concentration of silicon oxide SiO ₂ and alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]). are possible adjustment of developability, for example, as disclosed in JP-a-54-62004, the molar ratio of SiO ₂ / Na ₂ O 1.0 to 1.5 (i.e. [SiO _2] / [Na ₂ O] is 1.0 to 1.5, and the content of SiO ₂ is 1 to 4% by mass, an aqueous solution of sodium silicate, as described in JP-B-57-7427 [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and the concentration of SiO ₂ is 1 to 4% by weight, and the developer is small on the basis of gram atoms of all alkali metals present therein. An alkali metal silicate comprising at least 20% by weight of potassium is preferably used, and the pH of the developer is preferably in the range of 9 to 13.5, more preferably 10 to 13. The developer temperature is preferably 15 to 40 ° C., more preferably 20 to 35 ° C. The development time is preferably 5 to 60 seconds, and more preferably 7 to 40 seconds.

Further, when the photosensitive lithographic printing plate is developed using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developer is added to the developer, so that the developer in the developer tank for a long time. It is known that a large amount of photosensitive lithographic printing plate can be processed without replacing the plate. This replenishment method is also preferably applied in the present invention. For example, the molar ratio of SiO ₂ / Na ₂ O in a developer as disclosed in JP-A-54-62004 is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] 1.0 to 1.5), an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4% by mass, and continuously or intermittently depending on the throughput of the lithographic printing plate precursor An aqueous solution of sodium silicate (replenisher) having a SiO ₂ / Na ₂ O molar ratio of 0.5 to 1.5 (ie, [SiO ₂ ] / [Na ₂ O] is 0.5 to 1.5) is used as a developer. In addition, the method disclosed in Japanese Patent Publication No. 57-7427, [SiO ₂
] / [M] is 0.5 to 0.75 (that is, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and the SiO ₂ concentration is 1 to 4% by mass. Using a certain alkali metal silicate developer,
[SiO ₂ ] / [M] of the alkali metal silicate used as the replenisher is 0.25 to 0.75.
(I.e., [SiO ₂ ] / [M ₂ O] is 0.5 to 1.5), and both the developer and the replenisher are based on the gram atoms of all alkali metals present therein. Thus, a developing method comprising at least 20% by mass of potassium is preferably used.

  The photosensitive lithographic printing plate thus developed is washed with water, surface active as described in JP-A Nos. 54-8002, 55-1115045 and 59-58431. It is post-treated with a desensitizing solution containing a rinse solution containing an agent and the like, gum arabic and starch derivatives. These treatments can be used in various combinations for the post-treatment of the photosensitive lithographic printing plate of the present invention. The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets. As plate cleaners used for removing stains on printing plates, conventionally known plate cleaners for PS plates are used. For example, CL-1, CL-2, CP, CN-4, CN, CG -1, PC-1, SR, IC (manufactured by Fuji Photo Film Co., Ltd.) and the like.

  In the present invention, a non-alkaline aqueous solution having a pH of 10 or less can also be used as a developer. For example, an aqueous solution containing water alone or water as a main component (containing 60% by mass or more of water) is preferable. An aqueous solution having a composition similar to that of generally known fountain solution and an aqueous solution containing a surfactant (anionic, nonionic, cationic, etc.) are preferred. The pH of the developer is preferably 2 to 10, more preferably 3 to 9, and still more preferably 4 to 8.

Examples of the anionic surfactant used in the developer used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkylbenzene sulfonic acid salts, branched chain. Alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts , Petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfate ester Salts, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates Examples thereof include salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

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

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

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

The developer used in the present invention may contain an organic solvent. Examples of the organic solvent that can be contained here include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons, and the like. (Toluene, xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and the following polar solvents.
Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl Alcoa Etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl) Acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).
If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, flammability can be obtained. From the viewpoint of properties, the solvent concentration is preferably less than 40% by mass.

  In the developer used in the present invention, as a water-soluble polymer compound, soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivative (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, Pullulan, polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. Can be contained.

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

As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  In addition to the above, the developer used in the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

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

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

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

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content in the developer is preferably 0.01 to 5% by mass.

Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content in the developer is preferably 0.01 to 5% by mass.
The development treatment with the non-alkaline aqueous solution in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs rubbing while conveying a lithographic printing original plate after image recording, Automatic processing for rubbing the lithographic printing plate after image recording set on the cylinder described in the specifications of Japanese Patent No. 5148746, US Pat. No. 5,568,768 and British Patent No. 2297719 while rotating the cylinder Machine. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized.
Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

As the plate making process of the lithographic printing plate precursor used in the plate making method of the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. Such heating promotes an image forming reaction in the photosensitive layer, and may have advantages such as improvement in sensitivity and printing durability, and stabilization of sensitivity. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, a problem such as covering up to an unexposed portion occurs. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

<On-machine development processing>
Specifically, as a method of printing without passing through the development processing step, after exposing the lithographic printing plate precursor to a printing press without passing through the development processing step, the lithographic printing plate precursor to the printing press For example, a method of exposing on a printing machine and printing as it is after mounting.

In the image recording layer of the lithographic printing plate precursor exposed like an image, the exposed portion becomes insoluble by polymerization and curing. When the exposed lithographic printing plate precursor is supplied with an oil-based ink and a water-based component and printed without being subjected to a development process such as a wet development process step, in the unexposed area, the oil-based ink and / or the water-based component, The uncured image recording layer is removed by dissolution or dispersion, and the hydrophilic support surface is exposed in that portion. On the other hand, in the exposed portion, the polymerized and cured image recording layer remains to form an oil-based ink receiving portion (image portion) having a lipophilic surface.
As a result, the aqueous component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the image recording layer in the exposed area, and printing is started. Here, the water-based component or oil-based ink may be first supplied to the plate surface, but the oil-based ink is first used in order to prevent the water-based component from being contaminated by the image recording layer in the unexposed area. It is preferable to supply. As the aqueous component and oil-based ink, a dampening water and printing ink for ordinary lithographic printing are used.
In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

[Lithographic printing plate precursor]
The lithographic printing plate precursor used in the present invention has an image recording layer containing (A) a polymerization initiator and (B) a polymerizable compound on a support, and is photosensitive within a wavelength range of 250 nm to 420 nm. Have.
Hereinafter, elements constituting the lithographic printing plate precursor will be described.

<(A) Polymerization initiator>
The polymerization initiator used in the present invention is a compound that generates radicals by light energy and initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group. In particular, the polymerization initiator alone or the polymerization initiator and It is a compound that generates radicals by absorbing light of 250 nm to 420 nm in combination with a sensitizer. As such a photo radical generator, a known polymerization initiator, a compound having a bond having a small bond dissociation energy, or the like can be appropriately selected and used.
The emission spectrum intensity of white light is strong in the visible region exceeding 400 nm, and a polymerization initiator having sufficient photosensitivity in that region is likely to cause fogging under white light. Therefore, absorption of the initiator and the sensitizer is difficult. The maximum is preferably 400 nm or less.

  Examples of the compound that generates radicals include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oxime ester compounds. And onium salt compounds.

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

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

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

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

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

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

Examples of the hexaarylbiimidazole compound include the specifications of JP-B-6-29285, US Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) )) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (
o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) ) Bididazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′ , 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 '
, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organoboron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. No. 131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, etc. The organic borate described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, or organic boron oxosulfonium complex, JP-A-6-175554 No. 6, JP-A-6-17555 Organoboron iodonium complex described in JP-A-9-188, organoboron phosphonium complex described in JP-A-9-188710, JP-A-6-34811, JP-A-7-128785, JP-A-7-140589, Examples thereof include organoboron transition metal coordination complexes such as Kaihei 7-306527 and JP-A-7-292014.

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

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. Compounds, compounds described in JP-A No. 2000-80068, specifically, compounds represented by the following structural formulas may be mentioned.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt described in J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

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

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

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

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

  The polymerization initiator is not limited to the above, but particularly from the viewpoint of reactivity and stability, triazine-based initiators, organic halogen compounds, oxime ester compounds, diazonium salts, iodonium salts, and sulfonium salts can be exposed in a short time. This is more preferable because a large amount of radicals are generated.

  Furthermore, these triazine-based initiators, organic halogen compounds, oxime ester compounds, diazonium salts, iodonium salts, and sulfonium salt-based polymerization initiators are preferably used in combination with a sensitizer. By using in combination with a sensitizer, the photopolymerization rate can be increased.

Specific examples of such sensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, 9-fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, and 2-bromo-9. -Anthrone, 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9, 10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone , Xanthone, 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methylstyryl ketone, benzophenone, p- ( Dimethylamino) benzophenone (or mihi Keton), p- (diethylamino) benzophenone, and the like benzanthrone.

  Furthermore, preferred sensitizers in the present invention include compounds represented by the general formula (I) described in Japanese Patent Publication No. 51-48516.

In the formula, R ¹⁴ is an alkyl group (for example, methyl group, ethyl group, propyl group, etc.) or a substituted alkyl group (for example, 2-hydroxyethyl group, 2-methoxyethyl group, carboxymethyl group, 2-carboxyethyl group) Etc.). R ¹⁵ represents an alkyl group (eg, methyl group, ethyl group, etc.) or an aryl group (eg, phenyl group, p-hydroxyphenyl group, naphthyl group, thienyl group, etc.).

Z ² is a group of nonmetallic atoms necessary for forming a heterocyclic nucleus containing nitrogen, which is usually used in cyanine dyes, such as benzothiazoles (benzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, etc.), naphtho Thiazoles (α-naphthothiazole, β-naphthothiazole, etc.), benzoselenazoles (benzoselenazole, 5-chlorobenzoselenazole, 6-methoxybenzoselenazole, etc.), naphthoselenazoles (α-naphthoselenazole) , Β-naphthselenazole, etc.), benzoxazoles (benzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, etc.) and naphthoxazoles (α-naphthoxazole, β-naphthoxazole, etc.).

Specific examples of the compound represented by the general formula (I) are those having a chemical structure combining these Z ² , R ¹⁴ and R ¹⁵ , and many exist as known substances. Therefore, it can be used by appropriately selecting from these known ones. Furthermore, preferable sensitizers in the present invention include merocyanine dyes described in JP-B-5-47095 and ketocoumarin compounds represented by the following general formula (II).

Here, R ¹⁶ represents an alkyl group such as a methyl group or an ethyl group.

  As the sensitizer, merocyanine dyes described in JP-A No. 2000-147763 can also be used. Specifically, the following compounds can be mentioned.

  These polymerization initiators and sensitizers are each preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0. 0% by mass relative to the total solid content constituting the image recording layer. It can be added at a rate of 8 to 20% by mass. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<(B) Polymerizable compound>
The polymerizable compound that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one ethylenically unsaturated bond, preferably two or more. It is. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

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

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

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include, for example, aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, and JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

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

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

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238. Can obtain a photopolymerizable composition having an excellent photosensitive speed.

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

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

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass with respect to the total solid content constituting the image recording layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

<Binder polymer>
In the present invention, a binder polymer can be preferably used for improving the film strength and film property of the image recording layer and improving the on-press developability. A conventionally well-known thing can be used as a binder polymer without a restriction | limiting, The linear organic polymer which has film property is preferable. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.

  When performing an alkali development treatment, it is preferable to contain an acid group such as a carboxyl group, a sulfone group, or a phosphoric acid group. When performing an on-machine development treatment or a non-alkaline development treatment, a method not containing an acid group Is preferred.

The binder polymer preferably has crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.
Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and — (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadienyl. Represents a residue).
Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5
, —CH ₂ CH ₂ —NHCOO—CH ₂ CH═CH ₂ and —CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

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

Further, from the viewpoint of on-press developability of the image recording layer unexposed portion, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution.
In order to improve the solubility or dispersibility in ink, the binder polymer is preferably lipophilic, and in order to improve the solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. For this reason, in the present invention, it is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination.

  Examples of hydrophilic binder polymers include hydroxy groups, carboxyl groups, carboxylate groups, hydroxyethyl groups, polyoxyethyl groups, hydroxypropyl groups, polyoxypropyl groups, amino groups, aminoethyl groups, aminopropyl groups, and ammonium. Preferred are those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group.

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

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

The binder polymer can be synthesized by a conventionally known method. Solvents used in the synthesis include, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy. Examples include 2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, and water. These may be used alone or in combination of two or more.
As the radical polymerization initiator used for synthesizing the binder polymer, known compounds such as an azo initiator and a peroxide initiator can be used.

A binder polymer may be used independently or may be used in mixture of 2 or more types.
The content of the binder polymer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 30 to 70% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained.
Moreover, it is preferable to use (B) polymeric compound and binder polymer in the quantity used as 1 / 9-7 / 3 by mass ratio.

<Other image recording layer components>
In the image recording layer of the present invention, additives such as a surfactant, a colorant, a print-out agent, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, inorganic fine particles, and a low molecular weight hydrophilic compound are added as necessary. Can be contained. These will be described below.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the image recording layer in order to promote on-press developability at the start of printing and to improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

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

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

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

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

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

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

<Colorant>
In the present invention, various compounds other than these may be added as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

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

<Bakeout agent>
In the image recording layer of the present invention, a compound that changes color by an acid or a radical can be added to produce a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

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

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

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

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

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer of the present invention, and the surface of the image recording layer is dried during the coating process. It may be unevenly distributed. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

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

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

<Low molecular hydrophilic compound>
The image recording layer of the present invention may contain a hydrophilic low molecular weight compound for improving on-press developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Examples thereof include organic carboxylic acids such as salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid and amino acids, and salts thereof.

<Formation of image recording layer>
In the present invention, several modes can be used as a method for incorporating the above-mentioned image recording layer constituents into the image recording layer. One is a molecular dispersion type image recording layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, as described in, for example, JP-A-2001-277740 and JP-A-2001-277742, all or part of the constituent components are encapsulated in microcapsules and contained in the image recording layer. It is a capsule type image recording layer. In the microcapsule-type image recording layer, the components to be encapsulated can be included in a microcapsule at an arbitrary ratio, and the rest can be incorporated outside the microcapsule. Here, it is preferable that the microcapsule-type image recording layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule. In order to obtain better on-press developability, the image recording layer is preferably a microcapsule type image recording layer.

  As a method of microencapsulating the above-mentioned image recording layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation as described in the specifications of U.S. Pat. Nos. 2,800,047 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, and 42. -46 method by interfacial polymerization, US Pat. No. 3,418,250, US Pat. No. 3,660,304, by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol wall A method using a material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, a urea-formaldehyde system or a urea found in US Pat. Nos. 4001140, 4087376, and 4089802 Formaldehyde-resorcinol system A method using a forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and a monomer polymerization as shown in Japanese Patent Publication Nos. 36-9163 and 51-9079 In situ method, British Patent No. 930422, US Pat. No. 3,111,407 spray drying method, British Patent No. 952807, US Pat. No. 967074 specification, etc. It is not limited to these.

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

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

The image recording layer of the present invention is applied by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. 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-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The image recording layer of the present invention can also be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.3 to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Support>
The support used for the lithographic printing plate precursor in the plate making method of the present invention is not particularly limited as long as it is a dimensionally stable plate. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate.

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

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

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

  The support used for the lithographic printing plate precursor in the plate making method of the present invention is preferably a support having an anodic oxide film having micropores sealed as described below.

  The support used for the lithographic printing plate precursor in the image recording method and the lithographic printing method of the present invention is a support having an anodized film with micropores sealed on the surface. Specific examples include a metal plate, a paper or plastic film on which metal is laminated or vapor-deposited. A preferable support includes an aluminum plate having good dimensional stability and relatively inexpensive.

  The aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and a trace amount of foreign elements. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm.

  A surface roughening treatment is preferably performed before anodizing the aluminum plate. The surface roughening treatment makes it easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, and further neutralized to increase the wear resistance. Anodized.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, 1.5 to 4.
More preferably, it is 0 g / m ² . Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

The support used in the present invention is sealed with the micropores of the anodized film. By sealing, the specific surface area for the anodized film can be greatly reduced.
As the specific surface area of the support used in the present invention, the specific surface area measured by the BET method with respect to the mass of the anodized film provided on the surface is preferably 0.5 m ² / g or less. Here, the method for measuring the specific surface area is as follows.

<Method for measuring specific surface area>
"Specific surface area measurement principle"
When measuring a granular, powder, or porous sample based on the BET method, it can be calculated by the amount of gas of one layer of molecules adsorbed on the sample (so-called monomolecular layer). It is said to occur at or near the boiling point. Under specified conditions, it is known that the area where gas molecules cover the sample is limited to a relatively narrow area, and the surface area of the sample is the number of adsorbed molecules derived from the amount of gas under the specified conditions. , Calculated directly from the area occupied by the molecule. The parameters for forming the monomolecular layer at this time can be derived and set by data processing by a multipoint method.

"Specific measurement method"
A roughened surface, provided with an anodized film, a support with or without appropriate post-treatment was prepared, cut into a size that fits into the measurement cell, and used as measurement data.
The specific surface area was determined using a micromeritics automatic specific surface area measuring apparatus “Flowsorb III2305” (Shimadzu Corporation).
First, the sample cell is heated at 250 ° C. for 90 minutes to perform degassing work for removing gas generated from the sample surface, moisture absorbed from the atmosphere, and the like. Then, after measuring the sample mass, the sample cell is held in liquid nitrogen, and a gas of 99.9% helium + Kr (krypton) 0.1% is introduced into the cell to measure the amount of adsorption. After reaching equilibrium, return to room temperature and measure the amount of desorption. The specific surface area was calculated based on the adsorption amount, desorption amount and sample mass thus measured.

"Measurement method of anodic oxide film mass on substrate"
The amount of the anodized film on the substrate was determined by the following method.
30 g of chromium oxide (IV) chromic anhydride, 118 g of 85 mass% phosphoric acid, and 1500 g of pure water are weighed and mixed, and the substrate is immersed for 12 hours in a so-called Mason liquid, which dissolves only the anodized film. From the mass change, the amount (mass) of the anodic oxide film per unit area was determined.

The specific surface area obtained by the BET method is calculated with respect to the total mass of the support as a measurement sample. The surface area value (the value before dividing by the sample mass) thus obtained is divided by the anodized film mass corresponding to the sample surface area used for the measurement, thereby defining the “anodized film mass provided on the surface”. "Specific surface area measured by BET method".
For calibration of the specific surface area, commercially available alumina and silica fine particles (Admatex AO-502, SO-C1) whose specific surface area was announced were used, and the reliability of the value obtained by measuring each time was ensured.

  The sealing treatment used in the present invention is not particularly limited, and a conventionally known method can be used. Among them, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing with hot water are particularly preferable. Hole treatment is preferred. Each will be described below.

<Sealing treatment with an aqueous solution containing an inorganic fluorine compound>
As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably exemplified.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluoride titanate, potassium fluoride titanate, fluorinated zirconate, fluorinated titanate, hexafluorosilicic acid, nickel fluoride, iron fluoride, phosphor fluoride, ammonium fluoride phosphate It is done. Among these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

  The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, it is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  It is preferable that the aqueous solution containing an inorganic fluorine compound further contains a phosphate compound. When the phosphate compound is contained, the hydrophilicity of the surface of the anodized film is improved, so that on-machine developability and stain resistance can be improved.

Preferred examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Among these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. Is preferred.

  The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving on-press developability and stain resistance. Further, in terms of solubility, it is preferably 20% by mass or less, and more preferably 5% by mass or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When the treatment is performed using the dipping method, the treatment time is preferably 1 second or longer, more preferably 3 seconds or longer, and preferably 100 seconds or shorter, and 20 seconds or shorter. More preferred.

<Sealing treatment with water vapor>
Examples of the sealing treatment with water vapor include a method in which pressurized or normal pressure water vapor is brought into contact with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower.
The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq).
Further, the time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.

<Sealing treatment with hot water>
Examples of the sealing treatment with water vapor include a method in which an aluminum plate on which an anodized film is formed is immersed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt.
The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower.
Further, the time of immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, more preferably 100 seconds or shorter, and even more preferably 20 seconds or shorter.

  In the present invention, prior to the sealing, the micropore enlargement process of the anodized film as described in JP-A-2001-322365 can be performed. Further, after the sealing, a surface hydrophilization treatment can be performed.

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

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

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the image recording layer is provided on the undercoat layer. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed portion, and in the unexposed portion, the image recording layer is easily peeled off from the support. improves.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. A compound having a polymerizable group such as a methacryl group or an allyl group and a support adsorbing group such as a sulfonic acid group, a phosphoric acid group or a phosphoric acid ester is also preferred. Furthermore, a compound obtained by adding a hydrophilicity-imparting group such as an ethyleneoxy group to this compound is also suitable.
The coating amount (solid content) of the undercoat layer is preferably 0.1 to 100 mg / m ² ,
More preferably, it is 30 mg / m ² .

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

<Protective layer>
In the planographic printing plate precursor of the present invention used in the planographic printing method of the present invention, since the image formation by exposure is not easily affected by oxygen, a protective layer for the purpose of blocking oxygen is not necessarily required. However, if necessary, a protective layer is provided on the image recording layer in order to prevent scratches and the like in the image recording layer, to prevent ablation at the time of high-illuminance laser exposure, and to block oxygen to further increase the image strength. be able to.
In the present invention, the exposure is usually performed in the air, but the protective layer is an image of low molecular weight compounds such as oxygen and basic substances present in the air that inhibit the image forming reaction caused by exposure in the image recording layer. This prevents the recording layer from being mixed, and prevents the image formation reaction from being hindered by exposure in the air. Therefore, the properties desired for the protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion to the image recording layer, and It is preferable that it can be easily removed in an on-press development process after exposure. Various studies have been made on the protective layer having such characteristics, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

Examples of the material used for the protective layer include water-soluble polymer compounds that are relatively excellent in crystallinity. Specific examples include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic acid.
Among these, when polyvinyl alcohol (PVA) is used as a main component, the best results are obtained for basic characteristics such as oxygen barrier properties and development removability. The polyvinyl alcohol may be partially substituted with an ester, ether or acetal as long as it contains an unsubstituted vinyl alcohol unit for providing the oxygen barrier property and water solubility necessary for the protective layer, and a part of the other You may have a copolymerization component.
Specific examples of the polyvinyl alcohol include those having a hydrolysis degree of 71 to 100 mol% and a polymerization degree in the range of 300 to 2400. Specifically, for example, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA manufactured by Kuraray Co., Ltd. -HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405 , PVA-420, PVA-613, and L-8.

The components of the protective layer (selection of PVA, use of additives, etc.), coating amount, etc. are appropriately selected in consideration of fogging properties, adhesion, scratch resistance, etc. in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of PVA (that is, the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), and the thicker the film thickness, the higher the oxygen barrier property, which is preferable in terms of sensitivity. . Further, in order to prevent unnecessary polymerization reaction during production and storage and unnecessary fogging during image exposure, image line weighting, and the like, it is preferable that the oxygen permeability is not excessively high. Accordingly, the oxygen permeability A at 25 ° C. and 1 atm is preferably 0.2 ≦ A ≦ 20 (cc / m ² · day).

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

  In addition, adhesion of the protective layer to the image area, scratch resistance, and the like are extremely important in handling the lithographic printing plate precursor. That is, when a protective layer that is hydrophilic because it contains a water-soluble polymer compound is laminated on an image recording layer that is oleophilic, the protective layer is easily peeled off due to insufficient adhesion, and polymerization is inhibited by oxygen at the peeled portion. It may cause defects such as poor film hardening due to.

  On the other hand, various proposals have been made to improve the adhesion between the image recording layer and the protective layer. For example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, etc. in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on an image recording layer. Any of these known techniques can be used in the present invention.

Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of light used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

The thickness of the protective layer is suitably from 0.1 to 5 μm, particularly preferably from 0.2 to 2 μm.
The method for applying the protective layer is described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

1. Fabrication of support

<Support A>
In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolyte, then washed with water and dried. A support A was obtained.

<Support B>
As in the case of the support A, the support provided up to the anodic oxide film was added to a solution heated to 75 ° C. at pH 3.7 containing 0.1% by mass of sodium zirconate fluoride and 1% by mass of sodium dihydrogen phosphate for 10 seconds. It was immersed, sealed, washed with water and dried to obtain a support B.

<Support C>
The support provided up to the anodic oxide film in the same manner as the support A was treated with a 1% by mass aqueous solution of sodium hydroxide at 60 ° C. for 10 seconds to enlarge the pores of the anodic oxide film. By this treatment, the pore diameter of the anodized film was expanded to 20 nm.
After performing the pore-wide treatment, it was immersed for 10 seconds in a solution heated to 75 ° C. at pH 3.7 containing 0.1% by mass of sodium zirconate fluoride and 1% by mass of sodium dihydrogen phosphate,
Sealing treatment was carried out, followed by washing with water and drying to obtain a support C.

<Support D>
The support provided up to the anodic oxide film in the same manner as the support A was exposed to a saturated steam atmosphere at 100 ° C. for 10 seconds, subjected to sealing treatment, and dried to obtain a support D.

  About said support body A, B, C, D, it processed for 10 second at 30 degreeC with the 2.5 mass% sodium silicate aqueous solution, respectively. When the center line average roughness (Ra) of these supports was measured using a needle having a diameter of 2 μm, all were 0.51 μm.

Furthermore, the following undercoat liquid (1) was applied so that the dry coating amount was 5 mg / m ² , thereby preparing supports (A) to (D) used in the following experiments.

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

2. Preparation of lithographic printing plate precursor Preparation of lithographic printing plate precursor (1) (photopolymer plate material) An image recording layer coating liquid (1) having the following composition is applied on the above-mentioned undercoated support (B) by a dry coating mass. The coating was applied at 1.5 g / m ² and dried at 100 ° C. for 1 minute to form an image recording layer. A protective layer coating solution (1) having the following composition is coated thereon so that the dry coating mass is 2.5 g / m ² and dried at 120 ° C. for 1 minute to obtain a lithographic printing plate precursor (1). It was.

<Image recording layer coating solution (1)>
・ Tetramethylolmethane tetraacrylate 20 g
・ The following binder polymer (1) (average molecular weight 50,000) 30 g
・ The following polymerization initiator (1) 1 g
Ε-phthalocyanine / binder polymer (1) dispersion 2 g
・ Fluorine nonionic surfactant Megafac F177
(Dai Nippon Ink Chemical Co., Ltd.) 0.5g
・ Cuperon AL (nitroso compound, Wako Pure Chemical Industries, Ltd. 0.2g
・ Methyl ethyl ketone 200 g
・ Propylene glycol monomethyl ether acetate 200 g

<Protective layer coating solution (1)>
Polyvinyl alcohol (saponification degree 95 mol%, polymerization degree 800) 40 g
・ Polyvinylpyrrolidone (molecular weight 50,000) 5g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight of 75 g
・ 950g of water

Preparation of lithographic printing plate precursor (2) (on-press development plate material) After applying bar coating of image recording layer coating liquid (2) having the following composition on support (B) subjected to the above-mentioned undercoat, Oven-dried in seconds to form an image recording layer having a dry coating amount of 1.0 g / m ² , and the protective layer coating liquid (1) is dried thereon so that the dry coating mass is 0.5 g / m ^2. And dried at 120 ° C. for 1 minute to obtain a lithographic printing plate precursor (2).

<Image recording layer coating solution (2)>
・ 0.2 g of the above polymerization initiator (1)
・ The following binder polymer (2) (average molecular weight 80,000) 6.0 g
・ Polymerizable compound 12.4g
Isocyanuric acid EO-modified triacrylate (Aronix M-315 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 3.0g
・ Thermal polymerization inhibitor 0.1g
N-nitrosophenylhydroxylamine aluminum salt 0.1 g of tetraethylammonium chloride
・ 0.1 g of the following fluorosurfactant (1)
・ Methyl ethyl ketone 70.0g

Preparation of lithographic printing plate precursor (3) (microcapsule on-machine development plate material) A lithographic printing plate precursor except that the image recording layer coating solution (2) is changed to an image recording layer coating solution (3) having the following composition A lithographic printing plate precursor (3) was obtained in the same manner as in (2).

<Image recording layer coating solution (3)>
・ 0.2 g of the above polymerization initiator (1)
・ Binder polymer (2) (average molecular weight 80,000) 3.0 g
-Polymerizable compound 6.2g
Isocyanuric acid EO-modified triacrylate (Aronix M-315 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 3.0g
・ Thermal polymerization inhibitor 0.1g
N-nitrosophenylhydroxylamine aluminum salt 0.1 g of the above fluorosurfactant (1)
・ The following microcapsule (1) (in terms of solid content) 10.0 g
・ Methyl ethyl ketone 35.0g
・ 3-methoxy-2-propanol 35.0 g
・ Water 10.0g

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

Preparation of lithographic printing plate precursor (4) (on-press development plate material, initiator change) Other than changing polymerization initiator (1) used for preparation of lithographic printing plate precursor (2) to the following polymerization initiator (2) Produced a lithographic printing plate precursor (4) in the same manner as in the production of the lithographic printing plate precursor (2).

Preparation of lithographic printing plate precursors (5) to (7) (on-press development plate material, initiator change) The polymerization initiator (1) of the image recording layer coating solution (2) was changed to the following polymerization initiators (3) and (4) The lithographic printing plate precursors (5) and (6) were obtained in the same manner as the preparation of the lithographic printing plate precursor (2) except that 0.5 g of the following sensitizing dye (1) was added. . Further, the lithographic printing plate precursor except that the polymerization initiator (1) of the image recording layer coating liquid (2) is changed to the following polymerization initiator (3) and 0.5 g of the following sensitizing dye (2) is further added. A lithographic printing plate precursor (7) was obtained in the same manner as in the preparation of (2).

Preparation of lithographic printing plate precursors (8) and (9) (without protective layer) In preparation of the lithographic printing plate precursors (1) and (2), the lithographic printing plate before applying a protective layer on the image recording layer The original plates were lithographic printing plate precursors (8) and (9), respectively.

Preparation of lithographic printing plate precursor (10) (for comparative example) The polymerization initiator (1) used in the lithographic printing plate precursor (2) was changed to the following polymerization initiator (5) (λmax = 5
A lithographic printing plate precursor (10) was obtained in the same manner as in the production of the lithographic printing plate precursor (2) except that the thickness was changed to 10 nm.

Preparation of lithographic printing plate precursors (12) and (13) (support changed) The lithographic printing plate precursor except that the support (B) used in the lithographic printing plate precursor (2) was changed to supports (C) and (D). In the same manner as in the production of the printing plate precursor (2), lithographic printing plate precursors (12) and (13) were obtained, respectively.

Preparation of lithographic printing plate precursors (15) and (16) (support changed) The lithographic printing plate precursor except that the support (B) used in the lithographic printing plate precursor (6) was changed to supports (C) and (D). In the same manner as the production of the printing plate precursor (6), lithographic printing plate precursors (15) and (16) were obtained, respectively.

Preparation of lithographic printing plate precursors (18) and (19) (support changed) The lithographic printing plate except that the support (B) used in the lithographic printing plate precursor (7) was changed to supports (C) and (D). In the same manner as in the production of the printing plate precursor (7), lithographic printing plate precursors (18) and (19) were obtained, respectively.

[Examples 1 to 20]
The lithographic printing plate precursors (1) to (9), (12), (13), (15), (16), (18), and (19) produced as described above are used for image formation and printing. The sensitivity, fine line reproducibility and white light safety were evaluated. Below, the used exposure method, development method, printing method and evaluation method are shown. Table 1 shows the planographic printing plate precursor, the support, the presence or absence of a protective layer, the absorption maximum wavelength of the polymerization initiator used, the light source, the one-pixel drawing time, and the evaluation results used in each example.

[Comparative Examples 1 and 2]
Except that the one-pixel drawing time was changed as shown in Table 1, exposure and print evaluation were performed in the same manner as in Example 2. The results are shown in Table 1.

[Comparative Example 3]
Exposure and printing evaluation were performed in the same manner as in Example 2 except that the lithographic printing plate precursor (10) was used and the laser was changed to a 488 nm Ar laser and the one-pixel drawing time was changed as shown in Table 1. The results are shown in Table 1.

(1) Exposure Method <Examples 1 to 3 and 5 to 17, 19, 20, and Comparative Example 1>
The lithographic printing plate precursor was exposed to a semiconductor laser of 375 nm or 405 nm (Examples 7, 14, 15, 20) with a peripheral length of 900 mm using an exposure head composed of an optical system using the DMD spatial modulation element shown in FIG. The exposure was performed by adjusting the drum rotation speed and laser output so as to obtain the one-pixel drawing time and exposure energy shown in Table 1 at an outer drum at a resolution of 2400 dpi.

<In the case of Examples 4 and 18>
The lithographic printing plate precursor is subjected to inner drum by using a 266 nm (Example 4) which is a fourth harmonic of a YAG oscillation mode-locked solid-state laser shown in FIG. 4 and a 355 nm (Example 18) laser which is a third harmonic of a YAG oscillation solid-state laser. Under the conditions of the system and the resolution of 2400 dpi, the exposure was carried out by adjusting the spindle mirror rotation number and laser output capable of obtaining the one-pixel drawing time and exposure energy shown in Table 1.

<In the case of Comparative Examples 2 and 3>
In order to expose the lithographic printing plate precursor for 1 second, a 375 nm semiconductor laser (Comparative Example 2) or an argon ion laser 488 nm (Comparative Example 3) was used to diffuse a 100 mm diameter beam in a lens system, and surface exposure was performed. . The exposure was performed by adjusting the laser output and the exposure time so as to obtain the drawing time and exposure energy shown in Table 1. For evaluation of reproducibility of thin lines, exposure was performed using a test chart as a mask.

(2) Development treatment The development processing of the lithographic printing plate precursors (1) and (8) is carried out at 30 ° C. in a developer obtained by diluting a DP-4 developer (produced by Fuji Photo Film Co., Ltd.) 18 times with water. Dipped for 2 seconds. Next, the plate surface was treated with a solution obtained by diluting GU-7 gum solution (manufactured by Fuji Photo Film Co., Ltd.) twice with water.
The lithographic printing plate precursors (2) to (7) and (9) to (19) were subjected to on-press development without developing the exposed original plate as described in the printing method below.

  For the lithographic printing plate precursors (6) and (7), the plate surface was rubbed with a developing pad dipped in the following developer (1) separately from the on-machine development, and then washed with water (Example 19 and 20). The developer (1) had a solution temperature of 35 ° C. and a pH of 9 or less.

Developer (1)
・ Water 100g
・ Benzyl alcohol 1g
・ Polyoxyethylene sorbitan monooleate (HLB = 10.0) 1g
・ Dioctyl sulfosuccinate sodium salt 0.5g
・ Gum Arabic 1.5g
・ Phosphoric acid 0.1g

(3) Printing method The lithographic printing plate precursors (1) and (8) are developed and attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (manufactured by Fuji Photo Film Co., Ltd.) Etching solution) / water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) at a printing speed of 6000 sheets per hour. Printing was done.

  The lithographic printing plate precursors (2) to (7) and (9) to (19) are each attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing the exposed exposed original plate. Using Shimizu (IF201 (Effect manufactured by Fuji Photo Film Co., Ltd.) / Water = 4/96 (volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After supplying dampening water and ink, 100 sheets were printed at a printing speed of 6000 sheets per hour. Removal of the unexposed portion of the image recording layer on the printing machine was completed, and a printed matter having no ink smear in the non-image portion was obtained.

(4) Evaluation of lithographic printing plate precursor <Sensitivity>
After 100 sheets were printed and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were continuously printed. In the total 600th printed matter, the minimum exposure amount with no unevenness in the ink density in the image area was measured as sensitivity.

<Thin wire reproducibility>
About the planographic printing plate precursor exposed at the exposure amount determined in the sensitivity evaluation, as described above, after printing 100 sheets and confirming that a printed matter having no ink stains in the non-image area was obtained, 500 A sheet was printed. A thin line chart (10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100 and 200 μm fine line exposed charts) of a total of 600 printed sheets with a 25X magnifier The fine line reproducibility was evaluated based on the fine line width that was observed and reproduced with ink without interruption.

<Safety of white light>
An unexposed lithographic printing plate precursor was placed under a white fluorescent lamp and placed under conditions where the light amount of 400 lux was obtained on the surface of the lithographic printing plate precursor, and exposure was performed. These lithographic printing plate precursors exposed to white light were subjected to development processing for those requiring development processing, and then attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and printed 100 sheets as described above. Thereafter, the exposure time was measured under a white fluorescent lamp where no ink smear occurred. The longer this time, the better the white light safety.

  As is clear from the above results, the image recording method and lithographic printing method of the present invention have both high sensitivity and white light safety and high image quality with good fine line reproducibility.

[Examples 21 to 22]
Preparation of lithographic printing plate precursor (21)

Al: 99.5% by mass or more, Fe: 0.30% by mass, Si: 0.10% by mass, Ti: 0.02% by mass, Cu: 0.013% by mass, the balance being JIS of inevitable impurities The molten A1050 aluminum alloy was subjected to a cleaning treatment and cast. As the cleaning treatment, degassing treatment was performed to remove unnecessary gas such as hydrogen in the molten metal, and further ceramic tube filter treatment was performed. The casting method was a DC casting method. The surface of the ingot having a thickness of 500 mm was chamfered by 10 mm, and homogenized at 550 ° C. for 10 hours so that the intermetallic compound would not become coarse. Subsequently, it was hot-rolled at 400 ° C., subjected to intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, and then cold-rolled to obtain an aluminum rolled plate having a thickness of 0.30 mm. By controlling the roughness of the rolling roll, to control the center line average roughness R _a after cold rolling to 0.2 [mu] m. Then, it applied to the tension leveler in order to improve planarity. The obtained aluminum plate was subjected to the following surface treatment.
In order to remove the rolling oil on the surface of the aluminum plate, after degreasing at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, three bundled nylon brushes having a bristle diameter of 0.3 mm and the median The aluminum surface was grained using a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a diameter of 25 μm and thoroughly washed with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. This plate was provided with a direct current anodic oxide coating of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolyte, then washed with water and dried. Furthermore, it processed at 30 degreeC for 10 second with 2.5 mass% sodium silicate aqueous solution. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

An undercoat layer coating solution (21) having the following composition was coated on the support using a bar having a liquid volume of 7.5 ml / m ² and then oven-dried at 80 ° C. for 10 seconds. The image recording layer coating solution (21) having the following composition was applied by a bar and then oven-dried at 70 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ^2. The resulting protective layer coating solution (1) was applied so that the dry coating mass was 0.5 g / m ² and dried at 120 ° C. for 1 minute to obtain a lithographic printing plate precursor (21).

<Undercoat layer coating solution (21)>
・ 300 g of water
・ Methanol 2700g
-The following compound C-1 1.45g

<Image recording layer coating solution (21)>
・ The following polymerization initiator (4) 0.2 g
・ The following binder polymer (2) (average molecular weight 80,000) 6.0 g
・ Polymerizable compound 12.4g
Isocyanuric acid EO-modified triacrylate (M-315 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 3.0g
・ Thermal polymerization inhibitor 0.1g
N-nitrosophenylhydroxylamine aluminum salt ・ The following sensitizing dye (1) 0.5 g
・ Tetraethylammonium chloride 0.1g
・ 0.1 g of the following fluorosurfactant (1)
・ Methyl ethyl ketone 70.0g

<Protective layer coating solution (1)>
Polyvinyl alcohol (saponification degree 95 mol%, polymerization degree 800) 40 g
Polyvinylpyrrolidone (molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 75,5 g
950g of water

Preparation of lithographic printing plate precursor (22) The polymerization initiator (4) of the image recording layer coating solution (21) is the following polymerization initiator (3), and the sensitizing dye (1) is the following sensitizing dye (2). A lithographic printing plate precursor (22) was obtained in the same manner as in the production of the lithographic printing plate precursor (21), except for the changes.

Image formation and printing were performed using the lithographic printing plate precursors (21) to (22) produced as described above, and the sensitivity, fine line reproducibility, and white light safety were evaluated.
Exposure was performed by the following method. That is, the lithographic printing plate precursor was exposed to a semiconductor laser of 375 nm (Example 21) or 405 nm (Example 22) using an exposure head composed of an optical system using the DMD spatial modulation element shown in FIG. The outer drum was exposed at a resolution of 2400 dpi and adjusted to the drum rotation speed / laser output for obtaining the one-pixel drawing time / exposure energy shown in Table 2.
Development was performed in the same manner as in Examples 19 and 20. That is, the plate surface was rubbed with a developing pad immersed in the developer (1), and then washed with water. Here, the pH of the developer (1) was 9 or less, and the solution temperature was 35 ° C.
For printing, the obtained printing plate was attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 ( Volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), and the printing speed was 6000 sheets per hour.
The evaluation of the lithographic printing plate precursor was performed in the same manner as in the above example. The results are shown in Table 2.

  As is apparent from the above results, the image forming method and lithographic printing method of the present invention (Examples 21 to 22) have both high sensitivity and white light safety and high image quality with good fine line reproducibility.

It is a figure which shows the recording sensitivity of the recording material which produces fog when irradiated with a white fluorescent lamp for 2 hours. It is a figure which shows the light emission distribution of a white fluorescent lamp. It is a figure which shows the irradiation energy required for image formation with respect to irradiation time. It is a conceptual diagram which shows the cylindrical inner surface scanning light beam scanning apparatus used for this invention. (A) And (b) is the top view and side view of one Embodiment showing the structure of the image recording apparatus of the outer drum system used for this invention, respectively. It is sectional drawing of the subscanning direction along an optical axis which shows the structure of the exposure head using a DMD spatial light modulation element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 UV laser 2 Electro-optic modulation element 3 Half mirror 4 Mirror 5 Photo detector D Drum Lo beam L1, L2, L3 Lens 10 Image recording device 12 Exposure head 14 Drum 16 Broad area array laser diode 18 Cylindrical lens 20 Collimating lens 22, 26 λ / 2 plate 24 Ferroelectric liquid crystal shutter array 28 Analyzer 30, 32 Lens 40 Controller 50 DMD (Spatial light modulator)
56 Exposure surface 66 Fiber array optical system 67 Lens system 72 Lens system 74 Lens system 76 Micro lens array 78 Aperture 80 Lens system 82 Lens system

Claims (11)

  An image recording layer containing (A) a polymerization initiator and (B) a polymerizable compound on a support having an anodized film with micropores sealed on the surface, and having photosensitivity in the wavelength range of 250 nm to 420 nm. An image recording method for a lithographic printing plate comprising exposing a lithographic printing plate precursor having a laser beam having an oscillation wavelength in the range of 250 nm to 420 nm in an image-like manner with a one-pixel drawing time of 1 millisecond or less.   2. The image recording method according to claim 1, wherein the laser beam wavelength is any one selected from 405 nm, 375 nm, 365 nm, 355 nm and 266 nm.   2. The image recording method according to claim 1, wherein the exposure is performed using an optical system comprising a DMD or GLV modulation element and a semiconductor laser having a wavelength of 405 nm or 375 nm.   2. The image recording method according to claim 1, wherein the laser light wavelength is any one selected from 365 nm, 355 nm, and 266 nm, and exposure is performed by an inner drum system.   The image recording method according to any one of claims 1 to 4, wherein the image recording layer further contains (C) a binder polymer.   Printing on the exposed lithographic printing plate precursor obtained by the image recording method according to any one of claims 1 to 5 after being subjected to on-press development performed by supplying printing ink and / or fountain solution. Including lithographic printing methods.   A lithographic printing plate precursor having an image recording layer containing (A) a polymerization initiator and (B) a polymerizable compound and having a photosensitivity in a wavelength range of 250 nm to 420 nm on a support, in a wavelength range of 250 nm to 420 nm. A method for making a lithographic printing plate, comprising exposing a pixel drawing time of 1 millisecond or less using a laser beam that emits the light and developing with a developer.   8. The method of making a lithographic printing plate according to claim 7, wherein the support has an anodized film with micropores sealed as a surface.   The lithographic printing plate making method according to claim 7 or 8, wherein the developer is a non-alkaline developer having a pH of 10 or less.   The lithographic printing plate making method according to any one of claims 7 to 9, wherein the image recording layer further comprises (C) a binder polymer.   (C) The lithographic printing plate making method according to claim 10, wherein the binder polymer does not contain an acid group.

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