JP2007033777A - Processing method for photopolymerizable photosensitive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing method by which even in the case of a photopolymerizable photosensitive material requiring edge processing, faulty dissolution at ends and side faces of the support due to pressure fog does not occur in development, accordingly stable development can be performed. <P>SOLUTION: In the developing method for a photosensitive material, a photosensitive material in which side faces of the support has been chamfered (edge-processed) is processed with a developing device having at least one brush roller which rotates in a direction opposite to a transport direction of the photosensitive material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for processing a photopolymerizable photosensitive material in which a side surface of a support is chamfered (edge processing).

  In recent years, direct plate making systems using various lasers such as ultraviolet, visible, and infrared have been put into practical use and are widely spread in the field of general commercial printing. This direct plate making system is advantageous in comparison with conventional plate making systems using film in terms of speed, cost, stability, etc. by digitizing the system, and is becoming mainstream in today's general commercial printing market.

  Due to these advantages, the direct plate making system is spreading not only in the general commercial printing market but also in the newspaper printing market. In newspaper printing, printing conditions are severer than general commercial printing because of its large number of copies and high printing speed, and high printing durability is required for printing plates. For this reason, negative type photopolymerizable photosensitive materials capable of forming an image with higher strength by a crosslinking reaction than positive type photosensitive materials have been used in conventional film plate making systems. For this reason, a photosensitive material having high image strength was indispensable for introducing a direct plate-making system into the newspaper printing market.

  Conventional film-making systems using negative photosensitive materials cause a cross-linking reaction of the photosensitive layer by prolonged contact exposure with a very high energy light source such as a mercury lamp. The image obtained was very strong. In the direct plate making system, since exposure processing is performed with lower exposure energy than these light sources, it was initially difficult to form an image with the same intensity, but in recent years, various photosensitivities have been developed to improve the image intensity. Materials have been developed. In particular, high-power semiconductor lasers that emit light in the infrared region of 750 nm or more are becoming more compact and higher-powered and are very useful as exposure light sources for direct plate-making systems. In the plate making system, the development of photosensitive materials has made remarkable progress, and various proposals have been made. For example, the photosensitive material of Patent Document 1 includes a resol resin, a novolak resin, a latent Bronsted acid, and an infrared absorber, and describes a lithographic printing plate that can be used for both positive and negative plates. . Further, in Patent Document 2, a compound having a crosslinking property has a unique structure, and a binder is a polymer having an aromatic hydrocarbon ring in which a hydroxy group or an alkoxy group is directly bonded to a side chain or a main chain, and is heated by an acid. A negative-type image recording material containing a compound capable of generating odor and an infrared absorber is described.

  In particular, photopolymerizable photosensitive materials using boron salts as photopolymerization initiators can achieve high image intensity equivalent to negative photosensitive materials used in conventional film making systems by increasing the sensitivity. It was. In addition, since the heat treatment before and after the development processing, which has been required to ensure the image strength, is not required, the processing equipment does not require a heating device such as an oven, and energy consumption, installation area, and processing stability It is advantageous from the viewpoint of sex. For example, Patent Document 3 describes a light-sensitive material comprising a borate complex salt, a trihaloalkyl-substituted compound, and a sensitizing dye having absorption in a wavelength range from near infrared light to infrared light.

  However, the photopolymerizable photosensitive materials corresponding to these direct plate making have encountered problems that have not been seen in the field of newspaper printing and general commercial printing. It is a pressure fog caused by edge processing of a photosensitive material.

  Unlike general commercial printing, newspaper printing often requires frequent replacement of printing plates. Therefore, it is common to place multiple printing plates on a single plate cylinder and perform printing while replacing printing plates as necessary. . However, when a plurality of printing plates are printed side by side on a single plate cylinder, the border between adjacent printing plates appears linearly on the printed paper surface due to ink on the cut surface of the printing plate, so-called frame contamination. It becomes a printing failure called. In order to prevent this printing failure, a photosensitive material used for newspaper printing is generally subjected to processing called edge processing on the photosensitive layer support in the manufacturing process.

  Edge processing here is the process of chamfering the support material end surface of the photosensitive material, and when cutting the photosensitive material to the required size with a shearing machine such as a flying shear, guillotine shear, by adjusting the clearance of the cutter, This means that the edge of the surface on which the photosensitive layer is applied is scraped off. FIG. 1 is a cross-sectional view of a photosensitive material edge-processed by a shearing machine. In FIG. 1, a represents a support for the photosensitive material, and b represents an end face portion of the photosensitive material. Moreover, c shows the support body side part formed by the edge process. Further, A represents the horizontal length from the support end surface of the portion deleted by the edge processing, and B represents the vertical length from the photosensitive layer surface of the portion deleted by the edge processing. The values of A and B are not particularly limited, but are generally 50 μm to 200 μm. Further, the cross-sectional shape of the end face of the support 3 may be a straight line or a curved line. This edge treatment is generally performed using a shearing machine after a photosensitive layer is applied on a support.

  When this edge processing is performed, the photosensitive layer is locally subjected to a large pressure by a cutter of a shearing machine, and the photosensitive layer is strongly pressed against the support. The pressed photosensitive layer may be embedded in the support, or the components in the photosensitive layer may be altered by pressure, resulting in a change in dissolution during development. As a result, a phenomenon called so-called pressure fog occurs in which an elution failure portion is formed on the end face of the photosensitive material. In addition, the photosensitive layer sometimes wraps around the side surface of the support during the edge processing, and the wraparound photosensitive layer is difficult to hit the scraping portion for promoting dissolution of the non-image area during the development processing. In many cases, it remains on the plate as a poorly eluted portion without peeling off from the side of the body. These poorly eluted portions appear as residual films in various forms such as needles, thin layers, and grains near the edge processing portion of the photosensitive material after development, causing a plate making failure in printing plate making.

  If this poorly eluted portion cannot be completely removed by the developing unit of the plate making processing apparatus, it may lead to contamination of the processing apparatus, such as being transferred to a transport roll, causing a decrease in maintainability. Further, when the elution failure part is removed in a process other than the development process, the processing solution is contaminated in the process, and the process stability is lowered due to the reattachment of the elution defect part to the photosensitive material, and the plate making quality is lowered. When printing is performed with a printing plate in which the poorly eluted portion remains on the side surface portion of the plate, ink is attracted to the poorly eluted portion, so that a streak-like image line portion appears on the printed matter, which is a so-called frame stain.

A plate making apparatus having a reverse drive unit has been studied. For example, Patent Document 4 discloses a lithographic printing plate processing apparatus characterized by having a brush roller control unit that is driven in the direction opposite to the conveyance direction and a plate position detection unit that is to be processed to prevent generation of vignetting. Are listed. Patent Document 5 describes a printing plate developing device that prevents the occurrence of vignetting and rubbing unevenness in plate processing by combining a brush roller that rotates in the forward direction and a brush roller that rotates in the reverse direction with respect to the transport direction. . However, the plate subjected to the edge treatment and the pressure fog generated in that case are not described in any patent document.
Japanese Patent Laid-Open No. 7-20629 JP 2000-089452 A JP 2001-272778 A Japanese Patent Laid-Open No. 5-53325 Japanese Patent Laid-Open No. 2003-98681

  Accordingly, the problem of the present invention is that, even in a photopolymerizable photosensitive material that requires edge processing, there is no elution failure portion of the end surface portion of the photosensitive material due to pressure fog during development, and stable development processing can be performed. Is to provide a method for developing a printing plate free from frame smears.

It has been found that the above object of the present invention can be achieved by the processing method of the photopolymerizable photosensitive material described below.
1. A photosensitive material having a brush roller that rotates in a direction opposite to a conveying direction is processed on a photopolymerizable photosensitive material having a chamfered (edge-treated) side surface portion of a support. Development processing method.
2. A developing method for a photosensitive material, characterized in that the linear velocity of a brush roller rotating in the direction opposite to the conveying direction is faster than that of the conveying roller.
3. A method for processing a sensitive light material, wherein the photosensitive material is a photopolymerizable photosensitive material containing an organic boron salt as a photopolymerization initiator.

  According to the present invention, direct plate-making is possible, and even if edge processing is performed on a photopolymerizable photosensitive material having sufficient image strength, there is no elution failure of the end face of the photosensitive layer, and no frame smearing occurs in printing. A printing plate can be obtained.

  As a result of intensive studies by the present inventor, it has become clear that a plate making apparatus having a scraping unit that is driven in the direction opposite to the conveying direction of the photosensitive material is useful for the above-mentioned problems.

  The development processing apparatus in the present invention will be described below with reference to FIG. FIG. 2 is a sectional view of an automatic processor showing an example of the present invention. In FIG. 2, the photosensitive material subjected to the exposure processing is inserted into the developing device with the photosensitive layer surface facing upward, and is conveyed into the development processing unit 21 by the conveying rollers of rolls 1 and 2. Next, the photosensitive material is immersed in a developer whose temperature is controlled at a constant temperature through the conveyance assist skewer rolls 3 and 4 arranged in a staggered manner.

  In the photosensitive layer of the photosensitive material immersed in the developer, the unexposed portion which is a non-image portion is swollen by the developer and is in a state of being easily eluted, while the submerged transport rolls 9 and 10 and the transport assist skewer roll 6 to the scraping section. In addition, 5 is a shower pipe for developing solution stirring, and is not contacting the photosensitive material. The swollen non-image area is rubbed by the scraping roll 11 to promote elution. On the other hand, the image area that has undergone a crosslinking reaction by exposure hardly swells even in the developing solution and is not easily eluted. The remaining image is formed.

  Next, the photosensitive material is rubbed again by the scraping roll 13, and further elution of the swollen photosensitive layer is further promoted to obtain a cleaner non-image area. At this time, at least one of the scraping rolls 11 and 13 is rotating in the direction opposite to the conveying direction, and the side surface portion of the support is subjected to cutting and edge processing which cannot be scraped by the forward rotating scraping roll. The surrounding photosensitive layer is eluted and removed.

  The photosensitive material on which an image is formed by elution of the non-image area is removed from the developer through the conveyance assist skewer rolls of the rolls 7 and 8 arranged in a staggered manner, and then the conveyance roll and development of the rolls 15 and 16. The developer remaining on the plate surface is squeezed out by a liquid squeezing roll and conveyed to a water washing treatment unit 22. In the water washing treatment section 22, the photosensitive layer surface of the photosensitive material and the back surface of the support are washed, and then transported to the finishing processing section 23. In the finishing processing section, gumming is performed to neutralize the photosensitive material and form a protective film on the image area. Finally, the photosensitive material is dried in 24 drying processing sections.

  The configuration of the scraping part, which is a feature of the present invention, will be described in more detail. The installation location of the scraping roller that rotates in the direction opposite to the conveying direction (hereinafter referred to as a reverse scraping roll in the text) is not limited to 21 development processing units, 22 water washing processing units, Although it can be installed in any place of the 23 finishing processing sections, the development processing on the upstream side of the processing is considered when contamination of the processing apparatus and processing liquid in each process due to the poor elution portion of the photosensitive material is considered. It is desirable to be installed in the department. Also, the location of the reverse scraping roll is not particularly limited in the development processing section, but it is desirable to install it on the downstream side of the process in which the swelling of the photosensitive layer proceeds from the viewpoint of the elution promoting action of the non-image area.

  The scraping roll can be a combination of a scraping roll that rotates forward with respect to the conveying direction and a scraping roll that rotates reversely, but it is preferable that either scraping roll is in contact with the film surface of the photosensitive material to be processed. . Further, the number of the reverse scraping rolls may be one or a plurality, but it is desirable that the reverse scraping roll is in a range that does not adversely affect the transportability.

  Examples of the material for the forward and reverse scraping rolls include a channel brush roll, a molton roll, and a urethane roll. A channel brush roll is preferable from the viewpoint of wear resistance. Materials used for the channel brush roll include artificial fibers such as nylon, polyester, vinyl chloride, acrylic and polypropylene, natural fibers such as cotton, fern, bron, pakin, and horse hair, and metals such as steel, stainless steel, brass, and phosphor bronze. For example, it is desirable to use artificial fibers from the viewpoint of chemical resistance and the effect on the photosensitive material during scraping.

  Further, the roll diameter of the reverse scraping roll is not particularly limited, but the larger the roll diameter, the less the unevenness of scraping. Therefore, it is desirable to increase the roll diameter as long as the configuration of the apparatus is not hindered. In addition, when the rotational speed of the reverse scraping roll is converted to the linear speed from the roller diameter, it is desirable in terms of promoting elution of the non-image area that it is faster than the linear speed of the transport roller, but it is necessary for the transportability of the photosensitive material. It is desirable that the range has no effect.

  The reverse scraping roll of the present invention is used in the form of a roll pair that sandwiches the photosensitive material to be processed, and the position of the reverse scraping roll may be on the film surface side or the support opposite side of the photosensitive material, but it is said to promote elution of the non-image area In terms of the point, it is desirable to be disposed on the film surface side. The type of roll paired with the reverse scraping roll is not particularly limited, and may be a normal rubber roll or a scraping roll, but in order to give a uniform pressure to the photosensitive material A rubber roll is desirable.

  Next, the operation mechanism of the present invention will be described. When both of the scraping roll 11 and the scraping roll 13 in FIG. 2 rotate in the transport direction and the positive direction, the tip of the scraping roll contacts the upper surface of the plate when developing the photosensitive material. However, there is almost no contact with the side surface of the tip in the traveling direction. For this reason, in the photosensitive material in which pressure fogging has occurred due to the edge processing, an elution failure portion occurs. On the other hand, when one of the scraping roll 11 and the scraping roll 13 rotates in the direction opposite to the transport direction, the tip of the plate after the tip of the scraping roll hits the tip of the plate during the development process. Since it contacts the upper surface, it effectively acts to promote elution on the side surface of the support. For this reason, it is possible to obtain a clean end surface having no elution failure portion in the developing tank, and as a result, it is possible to prevent contamination of the processing liquid after the developing tank and the development processing apparatus itself. In addition, it is possible to obtain a good printed matter without frame stains even in printing.

  Next, the photosensitive composition used in the present invention will be described.

  As the polymerizable polymer used in the present invention, it is preferable to use a polymer having a polymerizable double bond in the side chain described below and having a carboxyl group-containing monomer as a copolymerization component. Polymers having a polymerizable double bond in the side chain and a carboxyl group-containing monomer as a copolymerization component include acrylic acid, methacrylic acid, acrylic acid 2-carboxyethyl ester, methacrylic acid 2-carboxyethyl ester, crotonic acid , Maleic acid, fumaric acid, maleic acid monoalkyl ester, fumaric acid monoalkyl ester, 4-carboxystyrene and the like.

  As monomers for introducing a polymerizable double bond into the polymer side chain, allyl acrylate, allyl methacrylate, vinyl acrylate, vinyl methacrylate, 1-propenyl-acrylate, 1-propenyl-methacrylate, β-phenyl-vinyl- Methacrylate, β-phenyl-vinyl-acrylate, vinyl methacrylamide, vinyl acrylamide, α-chloro-vinyl-methacrylate, α-chloro-vinyl-acrylate, β-methoxy-vinyl-methacrylate, β-methoxy-vinyl-acrylate, vinyl -Thio-acrylate, vinyl-thio-methacrylate and the like.

  Particularly preferred as the polymer used in the present invention is a polymer having a phenyl group substituted with a vinyl group as a polymerizable double bond in the side chain and a carboxy group-containing monomer as a copolymerization component. The phenyl group substituted with a vinyl group is bonded to the main chain directly or through a linking group, and the linking group is not particularly limited, and includes any group, atom, or a combination thereof. The phenyl group may be substituted with a substitutable group or atom, and the vinyl group is a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, It may be substituted with an aryl group, an alkoxy group, an aryloxy group or the like. More specifically, the polymer having a phenyl group in which a vinyl group is substituted on the side chain described above has a group represented by the following chemical formula 1 in the side chain.

In the formula, Z ₁ represents a linking group, and R ₁ , R ₂ , and R ₃ are a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, and an aryl group. A group, an alkoxy group, an aryloxy group, and the like, and these groups may be substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, or the like. R ₄ represents a substitutable group or atom. n ₁ represents 0 or 1, m ₁ represents an integer of 0 to 4, and k ₁ represents an integer of ₁ to 4.

The above general formula will be described in more detail. As the linking group for Z ₁ , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ₅ ) —, —C (O) —O—, —C (R ₆ ) ═N—, Examples include —C (O) —, a sulfonyl group, a heterocyclic group, and a group represented by the following chemical formula 2 alone or in combination of two or more. Here, R ₅ and R ₆ represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the above linking group may have a substituent such as an alkyl group, an aryl group, or a halogen atom.

Examples of the heterocyclic group include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thiatriazole ring, indole ring. , Indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline ring, quinoxaline ring, etc. A nitrogen-containing heterocyclic ring, a furan ring, a thiophene ring, and the like, and a substituent may be bonded to these heterocyclic rings.
Although the example of group represented by Chemical formula 1 is shown below, it is not limited to these examples.

Among the groups represented by the above chemical formula 1, preferred ones exist. That is, it is preferable that R ₁ and R ₂ are hydrogen atoms and R ₃ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.). Further, as the linking group for Z ₁ , those containing a heterocyclic ring are preferred, and those in which k ₁ is 1 or 2 are preferred.

  Examples of polymers having a group represented by Chemical Formula 1 and having a carboxy group-containing monomer as a copolymerization component are shown below. In the formula, the number represents the mass% of each repeating unit in 100% by mass of the total copolymer composition.

  The polymer of the present invention may further contain another monomer as a copolymer component. Other monomers include styrene derivatives such as styrene, 4-methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-carboxystyrene, 4-aminostyrene, chloromethylstyrene, 4-methoxystyrene, methyl methacrylate, Methacrylic acid alkyl esters such as ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and dodecyl methacrylate, aryl methacrylates or alkylaryl esters such as phenyl methacrylate and benzyl methacrylate , 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methoxydiethylene glycol monoester methacrylate, methoxyethylene methacrylate Methacrylic acid esters having an alkyleneoxy group such as glycol monoester and methacrylic acid polypropylene glycol monoester, amino group-containing methacrylic acid esters such as 2-dimethylaminoethyl methacrylate and 2-diethylaminoethyl methacrylate, or acrylic acid esters Examples of these corresponding methacrylic acid esters, or monomers having a phosphoric acid group such as vinylphosphonic acid, amino group-containing monomers such as allylamine and diallylamine, or vinylsulfonic acid and its salts, allylsulfone Monomers having a sulfonic acid group such as acid and its salt, methallylsulfonic acid and its salt, styrenesulfonic acid and its salt, 2-acrylamido-2-methylpropanesulfonic acid and its salt As monomers having a nitrogen-containing heterocyclic ring such as 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, N-vinylcarbazole, or monomers having a quaternary ammonium base, 4-vinylbenzyltrimethylammonium chloride, acryloyloxyethyl Trimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, quaternized product of dimethylaminopropylacrylamide with methyl chloride, quaternized product of N-vinylimidazole with methyl chloride, 4-vinylbenzylpyridinium chloride, or acrylonitrile, methacrylonitrile, Acrylamide, methacrylamide, dimethylacrylamide, diethylacrylamide, N-isopropyl acrylate Acrylamide or methacrylamide derivatives such as amide, diacetone acrylamide, N-methylol acrylamide, N-methoxyethyl acrylamide, 4-hydroxyphenyl acrylamide, acrylonitrile, methacrylonitrile, phenylmaleimide, hydroxyphenylmaleimide, vinyl acetate, chloroacetic acid Vinyl esters such as vinyl, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate, vinyl ethers such as methyl vinyl ether, butyl vinyl ether, and others, N-vinyl pyrrolidone, acryloylmorpholine, tetrahydrofurfuryl methacrylate, vinyl chloride , Various monomers such as vinylidene chloride, allyl alcohol, vinyltrimethoxysilane, glycidyl methacrylate, etc. And the like.

  There is a preferable range for the molecular weight of the polymer according to the present invention, and the mass average molecular weight is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 5,000 to 500,000.

  As the organic boron salt of the present invention, a compound having an organic boron anion represented by Chemical formula 12 is used.

In the chemical formula 12, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ may be the same or different, and may be an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group, heterocyclic group. Represents. Of these, it is particularly preferred that one of R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ is an alkyl group and the other substituent is an aryl group.

  As said organic boron salt, it is a salt containing the organic boron anion represented by the chemical formula 12 shown previously, and an alkali metal ion and an onium compound are preferably used as a cation which forms a salt. Particularly preferable examples of the onium salt with an organic boron anion include ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Examples of particularly preferred organic boron salts are shown below.

  There is a preferable range for the proportion of the organic boron salt in the photosensitive layer, and the organic boron salt is preferably contained in the range of 0.05 to 50 parts by mass in a total of 100 parts by mass of the photosensitive layer.

  The trihaloalkyl-substituted compound of the present invention is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. Preferred examples include the trihaloalkyl group. Examples of the compound bonded to the nitrogen heterocyclic group include s-triazine derivatives and oxadiazole derivatives, or a trihaloalkylsulfonyl compound in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group. Can be mentioned.

  Particularly preferred examples of trihaloalkyl-substituted nitrogen-containing heterocyclic compounds and trihaloalkylsulfonyl compounds are shown below.

  The proportion of the trihaloalkyl-substituted compound in the photosensitive layer is preferably included in the range of 0.005 to 50 parts by mass as the proportion in 100 parts by mass of the photosensitive layer.

  The photosensitive layer of the photosensitive lithographic printing plate of the present invention may contain a sensitizing dye. As the sensitizing dye to be added, those which sensitize the decomposition of the polymerization initiator in a wavelength range of 380 nm to 1300 nm, and various cationic dyes, anionic dyes and neutral dyes having no charge include merocyanine and coumarin. , Xanthene, thioxanthene, azo dyes and the like can be used. Among these, particularly preferable examples are dyes selected from cyanine, carbocyanine, hemicyanine, methine, polymethine, triarylmethane, indoline, azine, thiazine, xanthene, oxazine, acridine, rhodamine, and azamethine dyes as cationic dyes. It is. A combination with these cationic dyes is preferably used because it has particularly high sensitivity and excellent storage stability. Furthermore, in recent years, an output machine (plate setter) equipped with a violet semiconductor laser having an oscillation wavelength in the range of 380 to 410 nm has been developed. As a photosensitive system having high sensitivity corresponding to this output machine, a system containing a pyrylium compound or a thiopyrylium compound as a sensitizing dye is preferable. Examples of compounds are shown below.

  Examples particularly preferred as sensitizing dyes in a system in which light in the near-infrared to infrared wavelength region of 750 nm or more has photosensitivity are shown below.

  There is a preferred range in the quantitative ratio between the sensitizing dye and the polymerization initiator as described above. The trihaloalkyl-substituted compound is preferably used in the range of 0.01 to 100 parts by weight with respect to 1 part by weight of the sensitizing dye.

  The photosensitive layer of the photosensitive lithographic printing plate of the present invention preferably contains a polymerizable monomer. By combining this, a higher sensitivity can be realized, and a lithographic printing plate excellent in printing performance can be obtained.

  Examples of the polymerizable monomer include polymerizable compounds having a polymerizable double bond. Examples of preferred polymerizable monomers include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate. Examples thereof include polyfunctional acrylic monomers such as acrylate, ethylene glycol glycerol triacrylate, glycerol epoxy triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

  Alternatively, an oligomer having radical polymerizability is preferably used in place of the above-described polymerizable compound, and polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. as various oligomers into which acryloyl group or methacryloyl group is introduced Are also used in the same manner, but these can also be preferably used as ethylenically unsaturated compounds.

  A more preferable embodiment of the polymerizable monomer includes a polymerizable compound having two or more phenyl groups substituted with vinyl groups in the molecule. When this compound is used, crosslinking is effectively performed by recombination of styryl radicals generated by the generated radicals, which is extremely preferable for producing a highly sensitive photosensitive lithographic printing plate.

  A polymerizable compound having two or more phenyl groups substituted with vinyl groups in the molecule is typically represented by the following general formula.

In the formula, Z ₂ represents a linking group, and R ₂₁ , R ₂₂ and R ₂₃ are a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, and an aryl group. An alkoxy group, an aryloxy group, and the like, and these groups may be substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, or the like. R ₂₄ represents a substitutable group or atom. m ₂ represents an integer of 0 to 4, and k ₂ represents an integer of 2 or more.

Further details will be described. As the linking group for Z ₂ , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ₂₅ ) —, —C (O) —O—, —C (R ₂₆ ) ═N—, Examples include —C (O) —, a sulfonyl group, a heterocyclic group, or a group in which two or more are combined. Here, R ₂₅ and R ₂₆ represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the above-described linking group may have a substituent such as an alkyl group, an aryl group, or a halogen atom.

  Examples of the heterocyclic group include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thiatriazole ring, indole ring. , Indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline ring, quinoxaline ring, etc. A nitrogen-containing heterocyclic ring, a furan ring, a thiophene ring and the like, and a substituent may be bonded to these.

Among the compounds represented by the formula 26, there are preferred compounds. That is, R ₂₁ and R ₂₂ are hydrogen atoms, R ₂₃ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.), and k ₂ is preferably a compound having 2-10. Specific examples of the compound represented by Chemical Formula 26 are shown below, but the invention is not limited to these examples.

  There is a preferred range for the proportion of the polymerizable monomer as described above in the photosensitive layer of the photosensitive lithographic printing plate, and the polymerizable monomer is in the range of 1 to 60 parts by mass in 100 parts by mass of the photosensitive layer. It is preferable that it is contained in the range of 5 to 50 parts by mass.

  The photosensitive layer of the photosensitive lithographic printing plate of the present invention preferably contains a colorant. It is used for improving the visibility of the image area, and more preferably has absorption in the visible light region in order to improve the safelight property. It is also preferable to contain a colorant in the photosensitive wavelength region for improving the image quality. Examples of these colorants include inorganic pigments, organic pigments, and dyes as described below.

  Examples of the inorganic pigment include mica-like iron oxide, red lead, yellow lead, silver vermilion, ultramarine, titanium dioxide, coated mica, strontium chromate, titanium yellow, zinc chloroformate, molybdenum red, chromium oxide, calcium leadate, and the like. Organic pigments include carbon black, phthalocyanine pigment, monoazo pigment, disazo pigment, condensed azo pigment, isoindolinone pigment, quinophthalone pigment, nickel azo pigment, perinone pigment, perylene pigment, anthrone pigment, quinacridone pigment, anthraquinone pigment, Examples thereof include thioindigo pigments, dioxazine pigments, indanthrone pigments, and pyranthrone pigments. Examples of the dye include various dyes such as a phthalocyanine dye, a triarylmethane dye, an anthraquinone dye, and an azo dye.

  The above pigments and dyes may be used alone or in combination of two or more.

  A polymerization inhibitor can also be preferably added as another element constituting the photosensitive lithographic printing plate. For example, compounds such as quinone and phenol are preferably used, and compounds such as hydroquinone, p-methoxyphenol, catechol, t-butylcatechol, 2-naphthol, and 2,6-di-t-butyl-p-cresol are used. Preferably used. The preferred proportion of these polymerization inhibitors and the aforementioned ethylenically unsaturated compounds is preferably used in the range of 0.001 to 0.1 parts by mass with respect to parts by mass of the ethylenically unsaturated compounds.

  For the support used in the present invention, for example, a film or polyethylene-coated paper may be used, but a more preferable support is an aluminum plate that is polished and has an anodized film. The polished aluminum plate having an anodized film as used herein refers to an aluminum support generally used for a lithographic printing plate. In general, the surface of an aluminum support used for a lithographic printing plate is roughened in order to improve wettability (water retention) with respect to a fountain solution during printing and adhesion with a photosensitive layer. This roughening treatment (so-called graining) is performed by mechanically roughening treatment such as ball graining, wire graining or brush graining, or by chemically dissolving aluminum with chloride, fluoride or the like. A chemical surface roughening treatment, an electrolytic surface roughening treatment performed by electrochemically dissolving aluminum, and a surface roughening method using these methods in combination are known. For example, JP-A 48-28123, 53-123204, 54-146234, 55-25381, 55-132294, 56-55291, 56-150593, 56-28893, No. 58-167196, U.S. Pat. Nos. 2,344,510, 3,861,917, and 4,301,229. Regarding the surface shape of the aluminum plate, U.S. Pat. No. 2,344,510 is a grained structure in which mechanical roughening and electrolytic roughening are combined and superimposed, and U.S. Pat. No. 4,301,229 is pit. Cumulative frequency distribution of diameters and centerline average roughness, US Pat. No. 3,861,917 is the depth of the rough surface, Canadian Patent No. 955449 is the height and diameter of the rough surface, West German Patent 1,813, No. 443 describes the level difference of the rough surface. After such surface roughening treatment, anodization treatment is performed in an electrolytic solution such as sulfuric acid, phosphoric acid, nitric acid or a mixture thereof.

  As the developer of the present invention, any aqueous alkaline solution can be used as long as the pH is 8 or more. Examples of the alkali agent include sodium hydroxide, potassium hydroxide, ammonium hydroxide, lithium hydroxide, sodium borate, potassium borate, ammonium borate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium carbonate, Inorganic alkaline agents such as potassium carbonate, ammonium carbonate, dibasic sodium phosphate, dibasic potassium phosphate, dibasic ammonium phosphate, trisodium phosphate, tribasic potassium phosphate and tribasic ammonium phosphate, monomethylamine , Dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine , Monoisopropanolamine, diisopropanolamine, triisopropanolamine, N-ethylethanolimine, Nn-butylethanolamine, Nt-butylethanolamine, Nn-butyldiethanolamine, Nt-butyldiethanolamine N-methylethanolamine, N-methyldiethanolamine, N-aminoethylethanolamine, N-aminoethylpropanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. Examples include organic alkali agents, alkali metal silicates such as sodium silicate, potassium silicate and lithium silicate, and ammonium silicate. These can be used alone or in combination of two or more.

  The developer used in the present invention can be used in combination with other various surfactants, and examples thereof include anionic, cationic, nonionic and amphoteric surfactants. These surfactants used in combination are added to the developer in the range of 0.001 to 10% by mass, more preferably 0.01 to 5% by mass.

  Various developing stabilizers can be used in the developer used in the present invention. Preferred examples thereof include polyethylene glycol adducts of sugar alcohols described in JP-A-6-282079, phosphonium salts such as tetrabutylphosphonium bromide, and iodonium salts such as diphenyliodonium chloride. Furthermore, anionic surfactants or amphoteric surfactants described in JP-A-50-51324, water-soluble cationic polymers described in JP-A-55-95946, and JP-A-56-142528 are described. There are water-soluble amphoteric polyelectrolytes that have been described. Further, an organic boron compound to which an alkylene glycol is added as described in JP-A No. 59-84241, a polyethylene glycol having a weight average molecular weight of 300 or more as described in JP-A No. 61-215554, and a cation as described in JP-A No. 63-175858. And a water-soluble ethylene oxide adduct obtained by adding 4 mol or more of ethylene oxide to an acid or alcohol disclosed in JP-A-2-39157, a water-soluble polyalkylene compound, and the like.

  It is advantageous in terms of transportation that the developer used in the present invention is a concentrated solution in which the water content is less than that in use, and is diluted with water at the time of use. The degree of concentration in this case is suitably such that each component does not cause separation or precipitation, and depending on the content, it can usually be concentrated to about concentrate: water = 1: 0 to 1:10. In addition, since the developer is alkaline, it is preferable to use a material that does not transmit carbon dioxide as a container and that does not break during transportation for safety. Usually, resin containers such as hard bottles and cubicles are used. Preferably used.

  The printing plate developed with the developer having such a composition is subjected to post-processing with a washing water, a rinse solution containing a surfactant, a finisher mainly composed of gum arabic or starch derivatives, or a protective gum solution. The In the post-treatment of the printing plate of the present invention, these treatments can be used in various combinations. For example, development → water washing → rinsing liquid treatment containing surfactant or development → water washing → finisher liquid treatment is a rinse liquid or finisher. Less liquid fatigue is preferred. Furthermore, a countercurrent multistage process using a rinse liquid or a finisher liquid is also a preferred embodiment. These post-processing are generally performed using an automatic developing machine including a developing unit and a post-processing unit. As the post-treatment liquid, a method of spraying from a spray nozzle or a method of conveying through a treatment tank filled with the treatment liquid is used. A method is also known in which a fixed amount of a small amount of washing water is supplied to the plate surface after development, and the waste liquid is reused as dilution water for the developer stock solution. In such automatic processing, each processing solution can be processed while being replenished with the respective replenishing solution according to the processing amount and operating time. In addition, a so-called disposable processing method in which treatment is performed with a substantially unused post-treatment liquid can also be applied.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples as well as the effects. The part in an Example shows a mass part and% shows the mass%.

  Prepare a photosensitive composition solution with the following formulation, and apply a dry film thickness of 2.0 μm on a grained and anodized aluminum plate with a thickness of 0.30 mm using a wire bar. A photopolymerizable photosensitive material was prepared.

<Photosensitive composition liquid>
Polymer 7 (P-3) 10% dioxolane solution 300 parts by weight Organic boron salt 14 (BC-5) 4 parts by weight Ethylenically unsaturated compound
Chemical formula 27 (C-5) 15 parts by mass Pentaerythritol tetraacrylate 10 parts by mass Sensitizing dye Chemical formula 24 (S-33) 0.8 parts by mass Colorant 25% phthalocyanine pigment MEK dispersion 15 parts by mass Polymerization inhibitor 2,6 -Di-t-butylcresol 0.1 parts by mass Trihaloalkyl-substituted compound
15 (T-4) 1 part by mass
0.1 part by mass Solvent 1,3-dioxolane 70 parts by mass
20 parts by mass of cyclohexanone

  The obtained photosensitive material was cut using a shearing machine, and the photosensitive material 1 subjected to edge processing and the photosensitive material 2 not subjected to edge processing were prepared by adjusting the clearance of the blade edge. The shape of the edge processing portion at this time is 50 μm in the horizontal direction from the end surface of the support, which is A in FIG. 1, and 50 μm in the vertical direction from the surface of the photosensitive layer, which is B in FIG. It was.

About the photosensitive material produced as mentioned above, laser irradiation energy is 50 mJ / at drum rotation speed 1000rpm using the external drum system plate setter (Dainippon Screen Manufacturing Co., Ltd. PT-R4000) which mounted 830 nm semiconductor laser. The exposure process was carried out with fixing to cm ² .

  Next, a processor (PS plate development processor PD-912, manufactured by Dainippon Screen Mfg. Co., Ltd.) having the structure shown in FIG. 2 was used as an automatic processor. For the rolls 11 and 13 of the scraping part, a Molton cover (Techno Roll Carambo) wrapped around a 35φ rubber roll was used, and the linear velocity was set to 2.0 m / min. In the development process, 2% by mass of potassium silicate and 1% potassium hydroxide were prepared using the photosensitive materials 1 and 2 as a developing solution under the condition that both of the rolls 11 and 13 of the scraping part were rotated forward and reverse, respectively, with respect to the transport direction. Development was performed using a developer in which 5% by mass and 0.5% by mass of benzyl alcohol were dissolved at a liquid temperature of 30 ° C. at a conveyance speed of 1.6 m / min, and Samples 1 to 5 were produced.

Moreover, as a comparative sample, a negative PS printing plate (trade name VNN) manufactured by Fuji Film Co., Ltd. was exposed using a contact printer P-627-GA manufactured by Dainippon Screen Mfg. Co., Ltd. Using this processor of the present invention having the structure shown in FIG. 2, the rolls 11 and 13 of the scraping section are rotated in the forward direction with respect to the transport direction, and a negative developer DN- made by the same company is developed as a developer. Sample 6 was developed using 6K.
Test 1 (pressure fog test)
The end portions and side portions of the samples 1 to 6 subjected to the development treatment were observed with a magnifying glass (100 times) and visually evaluated for the presence or absence of a poorly eluted portion, and the results are summarized in Table 1.

  As is apparent from the results in Table 1, the comparative sample 6 and the photosensitive material not subjected to edge processing were scraped off and produced by a development processing apparatus in which the rolls 11 and 13 were rotated in either the forward or reverse direction with respect to the transport direction. Samples 1 and 2 show no poor elution. On the other hand, in the sample 3 produced by the development processing apparatus in which both the rolls 11 and 13 are rotated forward by scraping the photosensitive material subjected to the edge processing, an apparent elution defect portion is recognized on the end face and the support side face portion. It can be seen that pressure fogging due to edge processing occurs. However, in the samples 4 and 5 produced by the development processing apparatus in which either of the rolls 11 and 13 is scraped off the photosensitive material subjected to the same edge processing and rotated in the direction opposite to the conveying direction, the photosensitive material end face and the support side face part are obtained. From this result, it can be seen that an improvement effect on pressure fogging by edge treatment is recognized by rotating the scraping roll in reverse.

Test 2 (printing test)
Samples 1 to 6 were mounted on an off-wheel printing machine (Mitsubishi Heavy Industries, Lithopia L-600), ink (Tokyo Ink, NEWS MAJOR BKP HC-S NEW Red) and dampening water (Sakata Inx, Eco Seven N-10. Using a 5% aqueous solution, printing was performed up to 50000 parts. The frame stains on the printed material were evaluated, and the results are summarized in Table 2.

  As is apparent from the results in Table 2, in Samples 1 and 2 that have not been subjected to edge processing, frame stains are seen on the printed matter regardless of the rotation direction of the scraping rollers 11 and 13 of the developing device. It can be seen that edge processing of the photosensitive material is necessary. However, even in the photosensitive material that has been subjected to the edge processing, frame stains are observed on the printed material in the sample 3 produced by the development processing device in which both the scraping rollers 11 and 13 are rotated forward with respect to the transport direction. On the other hand, in Sample 6 which is a comparative negative PS plate and Samples 4 and 5 which are produced by a developing processing apparatus in which either of the rolls 11 and 13 is rotated in the reverse direction, the photosensitive material which has been subjected to edge processing is scraped No frame smear on the printed material was observed. For this reason, even in a photosensitive material that requires edge processing, it is possible to eliminate frame contamination due to pressure fog by processing it with a developing processing apparatus having a scraping roll rotated in the direction opposite to the conveying direction.

  As an application example of the present invention, even if an edge treatment required in the newspaper printing field is applied to a photopolymerizable photosensitive material capable of direct plate making and having sufficient image strength, the photosensitive layer end face and support It is possible to obtain a printing plate that is free from elution on the side surfaces and that does not cause frame stains even during printing.

It is sectional drawing of the photosensitive material which carried out the edge process. It is sectional drawing of a processor.

Explanation of symbols

b End surface portion of photosensitive material c Side surface portion of photosensitive material support 11, 13 Scraping roll

Claims (3)

  A photosensitive material in which a side surface portion of a support is chamfered (edge processed) is processed by a development processing apparatus having at least one brush roller that rotates in a direction opposite to a conveyance direction. Development processing method.   A developing method for a photosensitive material, characterized in that the linear velocity of a brush roller rotating in the direction opposite to the conveying direction is faster than that of the conveying roller.   Photosensitive material characterized in that the photosensitive material has a copolymer of a monomer having a polymerizable double bond in the side chain and a carboxyl group-containing monomer as a polymerizable polymer, and an organic boron salt as a photopolymerization initiator. Material processing method.

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