Abstract: An aluminum alloy plate for lithographic printing that is capable of obtaining a lithographic printing plate support which is free from appearance defects and has a uniform surface after electrolytic graining treatment and of obtaining a lithographic printing plate having a long press life and an excellent scumming resistance is provided. The aluminum alloy plate for a lithographic printing plate is obtained by continuous casting in which an aluminum alloy melt is fed through a melt feed nozzle between a pair of cooling rollers and rolled as it is being solidified by the pair of cooling rollers, wherein the aluminum alloy plate contains 0.10 to 0.20 wt % of silicon and 0.10 to 0.40 wt % of iron, and wherein the aluminum alloy plate contains in solid solution 200 to 600 ppm of silicon and not more than 250 ppm of iron.

Abstract: Disclosed are a positive working planographic printing plate material comprising an aluminum support and provided thereon, a light sensitive layer, wherein the light sensitive layer contains an alkali soluble resin and pigment having on the surface a development restrainer and a positive working planographic printing plate material comprising an aluminum support and provided thereon, a lower light sensitive layer and an upper light sensitive layer in that order, each layer containing an alkali soluble resin, wherein at least one of the lower and upper light sensitive layers contains a pigment having on the surface a development restrainer.

Abstract: A laser sensitive lithographic printing plate comprises an electrochemically grained, anodized, hydrophilically treated aluminum substrate with a reflection optical density of 0.30 or higher; a free radical polymerizable photosensitive layer; and a water soluble or dispersible overcoat. The photosensitive layer comprises a polymeric binder, a free radical polymerizable monomer, a free radical initiator, and a sensitizing dye. Such dark aluminum substrate in combination with the hydrophilic treatment allows both clean background and good printing durability. Such plate can be exposed with a suitable laser at lower dosage to cause hardening in the exposed areas. The exposed plate can be developed with a regular liquid developer or with ink and/or fountain solution.

Abstract: A method for preparing a negative-working lithographic printing plate is provided which comprises the steps of (1) providing a lithographic printing plate precursor comprising on a grained and anodized aluminum support, having a hydrophilic surface, a coating comprising (i) polymer particles which are core-shell particles having a hydrophobic heat-softenable core and a hydrophilic shell and (ii) an infrared light absorbing agent, (2) exposing said coating to heat, thereby inducing coalescence of said polymer particles at exposed areas of said coating, and (iii) developing said precursor by applying a gum solution to said coating, thereby removing non-exposed areas of said coating from said support. According to the above method the printing plates exhibit after ageing an improved clean-out and a reduced background stain, resulting in toning-free printing.

Abstract: The present invention provides an aluminum alloy plate for use as a lithographic printing plate having an improved uniformity of a surface roughened by electrolytic etching and wherein streaking does not occur, and a method for producing the same. The present invention is characterized in comprising, in wt %, Fe: 0.1 to 0.6%; Si: 0.02 to 0.2%; Cu: 0.001 to 0.02%; Zn: 0.01 to 0.1%; Mg: 0.005 to 0.1%; Ti: 0.001 to 0.05%, and the remainder Al and inevitable impurities, and an average value of the crystal particle size is 60 ?m or less in a direction perpendicular to the rolling direction.

Abstract: An image recording material of the present invention comprises an anodized aluminum support, an intermediate layer containing a polymer having a carboxylic acid group in a side chain thereof and formed on the aluminum support, and a photosensitive layer containing at least 50% by weight or more of novolak type phenol resin and a photothermal conversion agent and recordable by IR laser beam. A planographic printing plate excellent in printing durability can be obtained by subjecting the image recording material imagewise to IR laser exposure treatment and to development treatment, and then heating the image recording material at 150 to 300° C.

Abstract: There are provided a negative-working photosensitive composition which can be cured by infrared rays and is less likely to suffer polymerization inhibition by oxygen during radical polymerization, and also exhibits high adhesion with a metal, and a negative-working photosensitive lithographic printing plate which is capable of directly forming images by irradiation with infrared rays from a solid or semiconductor laser based on digital signals, and also has high sensitivity and excellent printing durability. The negative-working photosensitive composition contains an infrared absorber (A), an organoboron compound (B) which functions as a polymerization initiator by using in combination with the infrared absorber (A), a compound having a polymerizable unsaturated group (C) and a diazo resin (D), and the negative-working photosensitive lithographic printing plate comprises a support, and a photosensitive layer containing the negative-working photosensitive composition formed on the support.

Abstract: Disclosed is an image forming method possessing the steps of producing a planographic printing plate via a development treatment of exposing a hydrophilic surface of an aluminum support by removing a thermosensitive image formation layer provided on the hydrophilic surface, that is not imagewise heated on a printing press, after imagewise heating a planographic printing plate material having the thermosensitive image formation layer provided on the hydrophilic surface of the aluminum support, and of treating the planographic printing plate with an ink cleaning agent after printing, wherein the hydrophilic surface is colored by a colorant having a solubility of 5-100 g, based on 1 liter of n-decane, and the colorant on the hydrophilic surface exposed after removing the thermosensitive image formation layer is removed in the above step of treating the planographic printing plate with an ink cleaning agent.

Abstract: A light-sensitive lithographic printing plate precursor comprising an aluminum support having an anodized film on both surfaces thereof and a photo-polymerizable light-sensitive layer on one side of the support, wherein the anodized film on the surface of the support opposite to the light-sensitive layer side is provided on the entire surface and an amount of the anodized film is 0.5 g/m2 or more.

Abstract: Radiation-sensitive element comprising (a) a substrate with at least one hydrophilic surface and (b) a radiation-sensitive coating on at least one hydrophilic surface of the substrate, wherein the coating comprises: (i) at least one free-radical polymerizable monomer and/or oligomer and/or polymer with at least one ethylenically unsaturated group each, (ii) at least one absorber selected from photoinitiators and sensitizers, which is capable of absorbing radiation of a wavelength in the range of 250 to 1,200 nm and (iii) at least one stabilizer comprising in its molecule at least one group capable of inhibiting free-radical polymerization, and at least one other group capable of sorption at the hydrophilic surface of the substrate.

Abstract: Disclosed is a presensitized plate composed of a support having thereon an image recording layer which includes: an infrared absorber (A) that is a cyanine dye having at least one fused ring composed of a nitrogen-containing heterocycle in combination with an aromatic ring or a second heterocycle, and having on the aromatic ring or second heterocycle an electron-withdrawing group or a heavy atom-containing group, a radical generator (B), and a radical-polymerizable compound (C), and which is removable with printing ink and/or dampening water. The presensitized of the present invention can be imaged with an infrared light-emitting laser to directly record an image from digital data on a computer or the like and is then subjected to on-machine development without carrying out a development step, which is capable of providing a large number of good impressions with a practical amount of energy.

Abstract: A photosensitive composition comprising: (A) a polymerizable compound represented by the following formula (I): A—{O—[(CH(—R1)CH(—R2))m—O]n—C(?O)—C(—R3)?CH2}p??(I) wherein R1, R2and R3 each represents a hydrogen atom or a methyl group, A represents a polyhydric alcohol residue or a polyhydric phenol residue, m represents an integer of from 1 to 6, n represents an integer of from 1 to 20, and p represents an integer of from 1 to 6; (B) an infrared absorber; and (C) an onium salt.

Abstract: Heat-sensitive element comprising a) an optionally pretreated substrate; b) a positive working coating comprising (i) at least 40 wt.-%, based on the dry weight of the coating, of at least one polymer soluble in aqueous alkaline developer selected from novolak resins, functionalized novolak resins, polyvinylphenol resins, polyvinyl cresols and poly(meth)acrylates with phenolic and/or sulfonamide side groups, (ii) 01-20 wt.-%, based on the dry weight of the coating, of at least one (C4-C20 alkyl)phenol novolak resin insoluble in aqueous alkaline developer, and (iii) optionally at least one further component selected from polymer particles, surfactants, contrast dyes and pigments, inorganic fillers, antioxidants, print-out dyes, carboxylic acid derivatives of cellulose polymers, plasticizers and substances capable of absorbing radiation of a wavelength from the range of 650 to 1,300 nm and converting it into heat.

Abstract: The present invention provides an imageable element including a lithographic substrate and an imageable layer disposed on the substrate. The imageable layer includes a radically polymerizable component, an initiator system capable of generating radicals sufficient to initiate a polymerization reaction upon exposure to imaging radiation, and a polymeric binder having a hydrophobic backbone and including both constitutional units having a pendant cyano group attached directly to the hydrophobic backbone, and constitutional units having a pendant group including a hydrophilic poly(alkylene oxide) segment. When the imageable element is imaged and developed, the resulting printing plate may exhibit improved on-press solvent resistance and longer press life.

Abstract: The present invention discloses printing plates comprising a substrate and a radiation-absorptive layer, wherein the radiation-absorptive layer comprises at least one modified pigment product. The modified pigment product comprises a pigment having attached at least one organic group and at least one amphiphilic counterion. Methods of imaging printing plates are also disclosed.

Abstract: The present invention provides an imageable member having an imageable layer including a heat-sensitive ionomer characterized by a net positive or negative charge, and a photothermal conversion material. The photothermal conversion material includes carbonaceous particles having thereon both an organic moiety including an ionic substituent having like charge as the ionomer, and a group represented by the formula —X-[NIon]p-Rterminal; wherein X represents an aromatic group or an alkyl group, NIon represents a non-ionic, non-ionizable group, Rterminal represents hydrogen, an aromatic group, an alkoxy group, or an alkyl group, and p is an integer from 1 to about 500. The heat-sensitive ionomer and modified carbonaceous particles can be formulated in water or water-miscible solvents without agglomeration.

Abstract: Both single-layer and multilayer imageable elements have a substrate and at least one imageable layer. The elements can be used to prepare either negative- or positive-working imaged elements, for example as lithographic printing plates. The imageable elements also include a radiation absorbing compound and a solvent-resistant polymer comprising pendant phosphoric acid groups, pendant adamantyl groups, or both. When this polymer comprises pendant adamantyl groups, they are connected to the polymer backbone through a urea or urethane group. The imageable elements have improved chemical resistance and thermal bakeability from the presence of the unique solvent-resistant polymer.

Abstract: A positive-working lithographic printing starting plate for an infrared laser is provided that includes a support having a hydrophilic surface and a heat-sensitive layer provided above the support. The heat-sensitive layer includes a water-insoluble and alkali-soluble resin, an infrared-absorbing dye, and a sulfonium salt represented by Formula below. The heat-sensitive layer increases its solubility in aqueous alkaline solution upon exposure to an infrared laser.

Abstract: The invention provides a polymerizable composition comprising: a binder polymer containing at least an acid group having an acid dissociation constant (pKa) of 5.5 or more and a radical addition polymerizable group, and a radical-generating compound capable of generating a radical with light or heat. Further, the invention provides a negative-working planographic printing plate precursor which has a recording layer containing the polymerizable composition. Use of the polymerizable composition of the invention provides a planographic printing plate precursor that is capable of forming high-quality images free from stains in non-image portions, and further has high strength in formed image portions and excellent printing endurance.

Abstract: The support for a lithographic printing plate obtained by performing graining treatment including electrochemical graining treatment on an aluminum plate, the aluminum plate is an aluminum plate which contains Fe of 0.02 to 0.29 wt %, Si of 0.03 to 0.15 wt %, Cu of 0.020 to 0.040 wt % and Ti of 0.050 wt % or less and whose remaining portion is composed of Al and unavoidable impurities. In addition, the support for a lithographic printing plate where surface area ratio and steepness obtained from three-dimensional data found with an atomic force microscope (AFM) each satisfies the specified conditions is excellent in printing performance (press life, scum resistance, sensitivity and cleaner press life or the like) and handling property (scratch resistance, fatigue fracture strength or the like) when the lithographic printing plate is prepared.

Abstract: The invention provides a negative image recording material comprising: a support and an image recording layer disposed on the support, the image recording layer comprising an amide-acid compound containing a carboxyl group and an amide group expressed by the following General Formula (1): wherein L11 represents a hydrogen atom or a hydrocarbon group having 30 or fewer carbon atoms which may have a substituent; and wherein the amide-acid compound is insolubilized by a thermal ring-closure reaction between the carboxyl group and the amide group. The invention further provides a negative image recording material comprising a support, an image recording layer disposed on the support, the image recording layer containing a polymerization initiator and a polymerizable compound, and an overcoat layer disposed on the image recording layer, the overcoat layer containing the amide-acid compound expressed by the General Formula (1).

Abstract: A negative-working, imageable element comprises a substrate and an IR-sensitive imageable layer comprising a dispersion of nanofibers of a preformed IR-sensitive polymer. The nanofibers can be composed of polyaniline, polypyrrole, or polythiophene. The IR-sensitive imageable layer containing the nanofibers can be imaged using infrared radiation and used for printing without further processing. Thus, both imaging and printing can be carried out on-press.

Abstract: An object of the present invention is to provide a support for lithographic printing plates provided with a photosensitive layer containing an acid generator and an acid-decomposable compound, that offers superior sensitivity, chemical resistance, print durability, and little scumming during printing. The present invention provides an aluminum support for a lithographic printing plate, the support being obtainable by treating a surface of an anodized aluminum plate with a treatment liquid comprising metal fluoride, metal phosphate salt, and perchlorate, and a base plate for a lithographic printing plate using the same.

Abstract: A heat-sensitive lithographic printing plate precursor comprising a support having thereon two image-forming layers each containing a polymer insoluble in water and soluble in an aqueous alkaline solution, wherein an upper layer of the image-forming layers contains a copolymer including a monomer unit represented by formula (A) defined in the specification.

Abstract: Disclosed is a printing plate material comprising a surface roughened aluminum support, and provided thereon, an image formation layer containing a heat-curable polymer having a main chain polymer in the main chain, and an acryloyl group or a methacryloyl group in the side chain, a glass transition temperature Tg of the main chain polymer being from 0 to 100° C., wherein the printing plate material is capable of being developed on a printing press.

Abstract: The present invention provides a lithographic printing plate precursor and a lithographic printing method using the lithographic printing plate precursor, which is capable of an image recording by infrared laser scanning and an on-press development and excellent in fine line reproducibility and press life while maintaining good on-press developing properties, the lithographic printing plate precursor comprising: a support; and an image recording layer capable of being removed by a printing ink and/or a fountain solution, in which the image recording layer comprises an infrared absorber and a graft polymer having a specific graft chain.

Abstract: A positive-working, heat-sensitive material for making a lithographic printing plate by direct-to-plate recording is disclosed. The material comprises a hydrophobized grained and anodized aluminum support and a layer comprising a compound capable of converting light into heat provided onto said support, said support being obtainable by RF plasma treatment of a grained and anodized aluminum support in the presence of a fluorine containing gas.

Abstract: Disclosed is a process for manufacturing an aluminum support for a planographic printing plate material, the process comprising the steps of electrolytically surface-roughening an aluminum plate in an electrolytic solution, employing a sinewave alternating current; and anodizing the surface-roughened aluminum plate, the electrolytically surface-roughening step comprising a first stage of electrolytically surface-roughening the aluminum plate in a first electrolytic solution containing hydrochloric acid as a main component at a current density of D1 for t1 at a quantity of electricity of Q1 and a second stage of electrolytically surface-roughening the aluminum plate in a second electrolytic solution containing hydrochloric acid as a main component at a current density of D2 for t2 at a quantity of electricity of Q2.

Abstract: Initiator system comprising: (a) at least one substance capable of absorbing IR radiation, (b) at least one compound capable of forming free radicals, and (c) at least one 1,4-dihydropyridine derivative of the formula (I)

Abstract: A lithographic printing plate precursor comprises an image-forming layer containing a polymerization initiator and a polymerizable compound, and a hydrophilic support, wherein the lithographic printing plate precursor comprises a compound containing at least one functional group having an interaction with a surface of the hydrophilic support.

Abstract: A method of preparing negative-working, single-layer imageable elements improves their storage stability in a humid environment. The method includes enclosing the coated imageable elements in a water-impermeable sheet material that substantially inhibits the transfer of moisture to and from the imageable element. Such imageable elements include a radiation-sensitive composition that includes a radically polymerizable component, an initiator composition to provide radicals upon exposure to imaging radiation, a radiation absorbing compound, and a polymeric binder having poly(alkylene glycol) side chains.

Abstract: A negative-working radiation-sensitive composition includes a polymeric binder comprising a polymer backbone and having attached thereto a carbazole derivative represented by the following Structure (I): wherein Y is a direct bond or a linking group, and R1 to R8 are independently hydrogen, or an alkyl, alkenyl, aryl, halo, cyano, alkoxy, acyl, acyloxy, or carboxylate groups, or any adjacent R1 through R8 groups can together form a carbocyclic or heterocyclic group or a fused aromatic ring. The composition can be sensitive to radiation having a maximum wavelength of from about 150 to about 1500 nm, and can be used to prepare negative-working imageable elements that be imaged and developed as lithographic printing plates.

Abstract: Disclosed is a manufacturing process of a printing plate material comprising a boehmite treated aluminum support, and provided thereon, an image formation layer containing water soluble resins or water dispersible resins, the process comprising the steps of surface roughening an aluminum plate, anodizing the surface roughened aluminum plate, boehmite treating the anodized aluminum plate to produce the boehmite treated aluminum support having boehmite protrusions with an average height of from 30 to 200 nm and an average base size of from 10 to 100 nm, coating a coating solution for the image formation layer on the resulting aluminum support to form a coated layer, and drying the coated layer to form the image formation layer on the aluminum support.

Abstract: The present invention provides an imageable element including a lithographic substrate and an imageable layer disposed on the substrate. The imageable layer includes a radically polymerizable component, an initiator system capable of generating radicals sufficient to initiate a polymerization reaction upon exposure to imaging radiation, and a polymeric binder having a hydrophobic backbone and including both constitutional units having a pendant cyano group attached directly to the hydrophobic backbone, and constitutional units having a pendant group including a hydrophilic poly(alkylene oxide) segment. The invention also provides a method for preparing a suitable polymeric binder. The method comprises contacting a combination of co-monomers in a solvent mixture consisting essentially of a (C1–C6) alkanol and water.

Abstract: Radiation-sensitive elements are described whose radiation-sensitive coating comprises both a photopolymerizable oligomer with a biuret structural unit and a photopolymerizable phosphazene oligomer.

Abstract: A process for manufacturing an aluminum support for a planographic printing plate material, the process containing the steps of: (a) electrolytically surface-roughening an aluminum plate in an electrolyte solution containing hydrochloric acid as a main component; and (b) anodizing the surface-roughened aluminum plate, wherein the step (a) contains: (i) a first stage which surface-roughens the aluminum plate employing a sine-wave alternating current; and (ii) a second stage which surface-roughens the aluminum plate employing a controlled sine-wave alternating current using a thyristor so that a current flow starts at a phase angle of 60 to 120 degree of an alternating current cycle.

Abstract: A lithographic printing plate precursor comprises: a support; and an image-forming layer including a fluoroaliphatic group-containing copolymer, wherein the fluoroaliphatic group-containing copolymer contains a repeating unit corresponding to monomer (i) below and a repeating unit corresponding to monomer (ii) below: (i) a specified fluoroaliphatic group-containing monomer, and (ii) at least one of a poly(oxyalkylene) acrylate and a poly(oxyalkylene) methacrylate.

Abstract: A presensitized plate comprising a support for a lithographic printing plate including an anodized layer formed on an aluminum plate and a recording layer recordable by infrared laser exposure on the support, wherein in a section of the anodized layer after the recording layer is provided, an atomicity ratio of carbon to aluminum (C/Al) represented by Auger Electron Spectroscopic analysis is 1.0 or less. In the case of being used as an on-machine development type, it exhibits a good on-machine development characteristic, a high sensitivity, a high press life, and high scum resistance during printing and while left (ink discharging). In the case of being used as a conventional thermal positive or negative working type, it exhibits an efficient use of heat for image formation, a high sensitivity, a high press life, and a slight possibility of scum occurrence at non-image areas.

Abstract: A process of producing a relief image printing plate, the process comprising the steps of providing a photosensitive printing element, quenching dissolved oxygen in the photosensitive resin layer by pre-exposing the photosensitive layer to one or more sources of actinic radiation, wherein the range of wavelengths spanned by the one or more sources of actinic radiation differs by no more than about 20 nm, and imagewise exposing the photosensitive resin layer to actinic radiation to crosslink and cure the photosensitive resin layer. The photosensitive composition typically comprises at least one photoinitiator that is present in the photosensitive composition in an amount sufficient to provide an optical density in the photosensitive composition of between about 0.05 and 0.43 at a wavelength used to pre-expose the photosensitive composition.

Abstract: The photosensitive resin composition comprising: (A) a resin containing (A1) a repeating unit having at least two groups represented by the specific general formula; and (B) a compound capable of generating an acid by the action with one of an actinic ray and a radiation.

Abstract: The present invention provides a copolymer comprising repeating units derived from (A) at least one fluoroalkyl (meth) acrylate represented by the following general formula (I) or (II): wherein, X1 represents —O— or —NR3—; R1 represents —H or —CH3; R3 represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms or a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms; R2 represents H or F; m is an integer ranging from 0 to 10; n is an integer of 2 or 3; and o and p each represents an integer of 1 or 2, and (B) at least one polyoxyalkylene group-containing ethylenically unsaturated monomer, and also provides an image-forming composition, a presensitized plate useful for preparing a lithographic printing plate, a paint composition or a photo resist composition comprising the copolymer.

Abstract: A photosensitive resin laminate comprising at least a support, a photosensitive resin layer and an IR ablation layer, wherein the IR ablation layer comprises an IR absorbent metal layer which is disposed in contact with the photosensitive resin layer.

Abstract: Method of on-press developing a thermosensitive lithographic printing member with ink and/or fountain solution is described. The printing member comprises on a substrate a thermosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to an infrared radiation. The printing member can be a pre-coated plate or can be prepared on press by coating a thermosensitive layer onto a substrate that is a sheet material or a seamless sleeve mounted on a plate cylinder or is the surface of a plate cylinder of the lithographic press.

Abstract: A presensitized plate in which an image recording layer is formed on a support for a lithographic printing plate obtainable by performing a treatment with an aqueous solution containing one or more divalent or multivalent cations at a concentration ranging from 0.0001 mol/L to less than 0.020 mol/L is excellent in both scum resistance and press life when processed into a lithographic printing plate.

Abstract: Imageable elements, useful as on press developable lithographic printing plate precursors, are disclosed. The elements comprise an imageable layer over a substrate and an one or more adhesion promoting ingredients. The imageable layer comprises a polymerizable compound and a polymeric binder. The adhesion promoting ingredients are titanium chelate and/or co-polymers of a monomer having a polethylene oxide side chain with a monomer having either an acidic group or an anhydride group that has been ring opened to form an acidic group or groups.

Abstract: A presensitized plate having: on an aluminum support, a thermosensitive layer containing a photothermal conversion agent which absorbs infrared rays and generates heat and a water-insoluble and alkali-soluble resin, of which solubility to an alkali aqueous solution increases by heating, wherein the aluminum support has a grained structure with large undulation and a grained structure with small undulation on a surface thereof. This presensitized plate is excellent in damage resistance and sensitivity, and after the plate is processed into a lithographic plate, it is also excellent in scum resistance and press life.

Abstract: A presensitized plate useful for making a lithographic printing plates comprises an aluminum substrate provided thereon with a photopolymerizable light-sensitive layer, wherein the light-sensitive layer comprises an ethylenically unsaturated bond-containing compound having at least three methacryloyl or acryloyl groups alone or in any combination in the molecule and the substrate is Substrate A, which has, on the surface, grained structures comprising medium waved structure whose average pore size ranges from 0.5. to 5 ?m and small waved structure whose average pore size ranges from 0.01 to 0.2 ?m, which are superimposed; or Substrate B, which has, on the surface, grained structures comprising large waved structure whose average wavelength ranges from 5 to 100 ?m, medium waved structure whose average pore size ranges from 0.5 to 5 ?m and small waved structure whose average pore size ranges from 0.01 to 0.2 ?m, which are superimposed.

Abstract: The present invention provides a thermal type planographic printing plate which is writable by infrared laser beam exposure, can record images with high sensitivity and can provide a high quality printed matter which does not have stains. The planographic printing plate comprises a recording layer which is writable by infrared-laser exposure on a support formed with an anodic oxidation coating having a predetermined density and/or vacancy ratio on a roughened surface of an aluminum substrate.

Abstract: A planographic printing plate precursor comprising: a substrate; a photosensitive layer disposed on the substrate, the photosensitive layer including a light-to-heat conversion agent and a compound, which is at least one of crosslinkable and polymerizable, with solubility of the photosensitive layer in an alkali developing solution being decreased by the effect of at least one of light and heat; and an overcoat layer including a polymer, which is hydrophobic and soluble in an aqueous alkali solution.

Abstract: Disclosed are a printing plate material capable of being developed on a printing press and its manufacturing method which comprises the steps of subjecting an aluminum plate to electrolytic surface roughening treatment, subjecting the electrolytic surface roughened aluminum plate to etching treatment in an aqueous alkali solution, subjecting the resulting aluminum plate to anodization treatment, whereby an aluminum support is obtained, and providing on the aluminum support an image formation layer which contains thermoplastic particles and a light-to-heat conversion dye and changes in color due to infrared laser exposure.