Abstract: While the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

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: The present invention provides an imageable element including a substrate, a first layer applied to the substrate and a second layer applied to the first layer. The first layer may contain polymeric material and a radiation absorbing compound. The second layer may contain a hydroxyl group-containing polymer that includes a heat-labile moiety.

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 negative-working CTP plate which is superior in resolution and printing resistance of the image area of a press plate is provided, which is obtained by forming a latent image on a heat-sensitive layer in a heat-sensitive lithographic printing plate comprising a substrate having a hydrophilic surface and a heat-sensitive layer made of an alkali-soluble polymer formed on the surface of the substrate, using heat generated upon irradiation with laser light, and developing the heat-sensitive layer using an alkaline developing solution. In the heat-sensitive lithographic printing plate comprising a substrate having a hydrophilic surface, and a heat-sensitive layer made of an alkali-soluble polymer formed on the surface of the substrate, an advancing contact angle (?f1) of the surface of the heat-sensitive layer with water at 25° C. is within a range from 70° to 110°, a receding contact angle (?b2) of the surface of the heat-sensitive layer with water at 25° C. after heating at 150° C.

Abstract: A heat-sensitive composition which forms an image without the removal of material, which does not require any developing treatment after the stage of exposure to heat and comprises: (a) a switchable polymer, (b) an IR absorber, (c) a triazine compound, and (d) a novolak resin. Negative lithographic plate comprising a substrate coated with the said composition. A method for obtaining a negative image on a substrate coated with a composition which is first hydrophobic and then lipophilic after exposure to heat, without the removal of material, the said negative image being obtained by applying a small quantity of energy to the said composition.

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: The positive type photosensitive composition of the present invention comprises a polymer compound (A) having, in a side chain thereof, a polymerizable group or a cross-linkable group, and an infrared absorbent (B). Preferably, the polymerizable group or cross-linkable group is incorporated into molecules of the polymer compound (A) through a structural unit having this group in a side chain thereof. Specifically, the structural unit is preferably a structural unit having any one of structures represented by the following general formulae (1) to (4): wherein A, B, X each independently represents a single bond, an oxygen atom, a sulfur atom or the like; L and M each independently represent a bivalent organic group; R1 to R12 represents a hydrogen atom or a monovalent organic group; R13 to R24 each independently represents a monovalent organic group; and Y represents an oxygen atom, a sulfur atom, or a phenylene group which may have a substituent.

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: Polymer materials are described that undergo a two-level three-dimensional crosslinking process. During this process, hydrophilic polymers are crosslinked at two levels, the first results in a low level of crosslinking which leads to a toughening of the layer preventing dissolution by the fountain solution but with the layer remaining hydrophilic. The second level of crosslinking is higher and is the result of exposure to a laser diode thermal imaging device. The crosslinking at this second level results in a loss of hydrophilicity and provides instead an oleophilic image capable of accepting and transferring oil-based ink. The polymer materials are particularly useful in lithographic printing systems where they may used in articles such as a printing plate comprising a substrate having coated thereon a layer that becomes less hydrophilic upon exposure to thermal energy (e.g.

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: A flexographic printing plate is prepared from a photosensitive element having a photopolymerizable elastomeric layer with specific rheological properties. The element is imagewise exposed and thermally treated to form a relief structure suitable for flexographic printing.

Abstract: A heat mode type negative image recording material is provided which comprises (A) a polymer compound that is insoluble in water but is soluble in an alkali aqueous solution and has at least one of groups represented by general formulae (1) to (3) on a side chain; (B) a photothermal conversion agent; and (C) an onium salt compound forming radicals by heat mode exposure with light that is capable of being absorbed by said photothermal conversion agent (B), said heat mode type negative image recording material being capable of recording an image by heat mode exposure. The general formulae are defined in the specification.

Abstract: A laser-engravable flexographic printing element comprising an elastomeric, relief-forming, laser-engravable, thermally and/or photochemically crosslinkable layer comprising, as binder, at least 5% by weight of syndiotactic 1,2-polybutadiene having a content of 1,2-linked butadiene units of from 80 to 100%, a degree of crystallinity of from 5 to 30% and a mean molecular weight of from 20,000 to 300,000 g/mol on a flexible, dimensionally stable support. The elastomeric, relief-forming, laser-engravable layer preferably comprises: (a) from 50 to 99.9% by weight of one or more binders as component A consisting of (a1) from 5 to 100% by weight of syndiotactic 1,2-polybutadiene having a content of 1,2-linked butadiene units of from 80 to 100%, a degree of crystallinity of from 5 to 30% and a mean molecular weight of from 20,000 to 300,000 g/mol as component A1, and (a2) from 0 to 95% by weight of further binders as component A2, (b) from 0.

Abstract: Imageable elements that contain silicate-coated polymer particles in the imageable layer, stacks of these elements, and methods for forming images using these elements are disclosed. The elements do not stick to each other when stacked without interleaving paper, and only one imageable element is lifted at a time when the imageable elements are handled by automatic processing equipment. Blanket piling is not observed when silicate-coated particles are present in the imageable layer.

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: A method of making a printing plate from a heat-sensitive PS plate of a positive-working mode for lithographic printing includes the steps of exposing the heat-sensitive PS plate to light and developing the PS plate using an alkaline developing solution containing at least one compound selected from the group consisting of cationic surfactants and compounds having three or more of an ethylene oxide-terminal group in the molecule thereof. The PS plate has a substrate and an image forming layer formed thereon, said image forming layer comprising a lower layer which is formed on the substrate and contains a water-insoluble and alkali-soluble resin and an upper heat-sensitive layer which is overlaid on the lower layer and contains a water-insoluble and alkali-soluble resin and an infrared absorption dye and exhibits an elevated solubility with respect to alkaline aqueous solutions when heated.

Abstract: A planographic printing plate precursor including: a support; and an image recording layer which is disposed on the support and contains a binder polymer, a polymerization initiator, a polymerizable compound, and an IR absorber. Upon exposure with a laser beam, an exposed portion of the image recording layer in the vicinity of the surface of the image recording layer is cured, and an exposed portion of the image recording layer in the vicinity of an interface between the image recording layer and the support is not cured. A developing rate of an unexposed portion of the image recording layer by an alkaline developer having a pH of 10 to 13.5 is preferably 100 nm/sec or more, and a permeation rate of the alkaline developer to an exposed portion of the image recording layer is preferably 100 nF/sec or less.

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 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: A method for making a lithographic printing plate comprising the steps of: light-exposing to infrared radiation, a heat-sensitive presensitized plate of a positive-working mode for use in making a lithographic printing plate, said presensitized plate comprising a substrate and an image recording layer which is formed thereon and comprises a novolak resin containing xylenol as a monomer component and an infrared absorbing dye; and developing the light-exposed plate with an alkaline developing solution comprising at least one surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants.

Abstract: An automated method of preventing edge curing of cut surfaces of photosensitive printing elements is disclosed. Once a photosensitive printing element is cut in a pattern of a desired size and shape, a portion of the coversheet on a periphery of the cut edges of the printing plate is removed, while leaving intact the layer of photocurable material and the optional ablation layer beneath the coversheet. Next, an edge cure prevention composition is applied to the optional ablation layer or the layer of photocurable material revealed by the removal of the portion of the coversheet. Once the edge cure prevention composition is dried, the remainder of the coversheet may be removed from the photosensitive printing element and the printing element may be mounted on a sleeve or cylindrical carrier for further processing. The method ensures that the edge cure prevention composition is applied only to areas where it is needed and does not affect imageable areas of the printing plate.

Abstract: Alkali soluble copolymers, imageable elements useful as lithographic printing plate precursors that contain the alkali soluble copolymers, and methods for forming images using the imageable elements are disclosed.

Abstract: A heat-sensitive composition which forms an image without the removal of material, which does not require any developing treatment after the stage of exposure to heat and comprises: (a) a switchable polymer, (b) an IR absorber, (c) a triazine compound, and (d) a novolak resin. Negative lithographic plate comprising a substrate coated with the said composition. A method for obtaining a negative image on a substrate coated with a composition which is first hydrophilic and then lipophilic after exposure to heat, without the removal of material, the said negative image being obtained by applying a small quantity of energy to the said composition.

Abstract: Multilayer, positive working, thermally imageable, bakeable imageable elements are disclosed. The elements have a substrate, an underlayer, and a top layer. The underlayer comprises a resin or resins having activated methylol and/or activated alkylated methylol groups, such as a resole resin, and a polymeric material that comprises, in polymerized form about 5 mol % to about 30 mol % of methacrylic acid; about 20 mol % to about 75 mol % of N-phenylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, or a mixture thereof; optionally, about 5 mol % to about 50 mol % of methacrylamide; and about 3 mol % to about 50 mol % of a compound represented by the formula: CH2C(R2)C(O)NHCH2OR1, in which R1 is C1 to C12 alkyl, phenyl, C1 to C12 substituted phenyl, C1 to C12 aralkyl, or Si(CH3)3; and R2 is H or methyl. The elements produce bakeable lithographic printing plates that are resistant to press chemistries.

Abstract: Co-polymers that contain siloxane groups, imageable elements that comprise the co-polymers, and methods for forming images by imaging and developing the imageable elements are disclosed. The imageable elements are useful as lithographic printing plate precursors that can be developed with water or with fountain solution.

Abstract: A lithographic printing plate precursor comprising a hydrophilic support, an alkali-soluble layer and provided on the alkali-soluble layer a recording layer which contains an infrared ray absorbent, an alkali-soluble resin and an inhibitor of inhibiting the alkali-soluble resin from dissolving in an alkali aqueous developer and increases in the solubility in an alkaline aqueous solution upon irradiation of infrared light, and a developing method of the lithographic printing plate precursor with a non-silicate developer.

Abstract: Disclosed are a printing plate material comprising a substrate and provided thereon, a component layer comprising a hydrophilic layer and an image formation layer, the hydrophilic layer being provided closer to the substrate than the image formation layer, wherein the hydrophilic layer contains an electron providing dye precursor, the image formation layer contains an organic electron accepting developing agent, and the component layer contains a light heat conversion material.

Abstract: A method of making a printing plate from a heat-sensitive PS plate of a positive-working mode for lithographic printing includes the steps of exposing the heat-sensitive PS plate to light and developing the PS plate using an alkaline developing solution containing at least one surfactant selected from the group consisting of anionic surfactants and ampholytic surfactants, and a salt selected from the group consisting of alkali metal salts and ammonium cation salts. The PS plate has a substrate and an image forming layer formed thereon, the image forming layer including a lower layer which is formed on the substrate and contains a water-insoluble and alkali-soluble resin and an upper heat-sensitive layer which is overlaid on the lower layer and contains a water-insoluble and alkali-soluble resin and an infrared absorption dye and exhibits an elevated solubility with respect to alkaline aqueous solutions when heated.

Abstract: The present invention aims to provide a near-infrared absorption film having excellent near-infrared blocking properties and visible light transparency over a wide wavelength range, and attractive appearance. It further aims to provide a near-infrared absorption film having excellent near-infrared blocking properties, visible light transparency, good appearance and excellent durability such as anti-deterioration properties. The film may comprise a transparent substrate, and a near-infrared absorption layer containing a cyanine compound represented by the formula (1), and a diimonium compound. wherein, in the formula (1), A is a divalent bonding group comprising ethylene. R1 and R2 are monovalent groups comprising a carbon atom. X? is a monovalent anion. The film may also comprise a transparent substrate, and a near-infrared absorption layer containing a layer containing the cyanine compound represented by the formula (1) and a layer containing a diimonium compound.

Abstract: A process for making a radiation filter element comprises the steps of: exposing part of an assemblage to infrared radiation, the assemblage comprising a donor comprising (1) a support capable of transmitting infrared light, and (2) a transferable layer comprising a transferable material and an infrared-absorbing dye, the transferable layer of the donor being in contact with a receiver to provide an exposed assemblage comprising an exposed part of the transferable layer and an unexposed part of the transferable layer; separating the receiver and the support of the exposed assemblage to obtain an imaged receiver and a spent donor, wherein the imaged receiver comprises the receiver, a transferred portion of the transferable material and a transferred portion of the infrared-absorbing dye, said transferred portion of the IR dye having a color and the spent donor comprises the support and a retained portion of the transferable layer; and heating the transferred portion of the transferable material and the transfe

Abstract: Infrared absorbing N-alkylsulfate cyanine compounds and imageable compositions containing the compounds are disclosed. The compounds have the structure I: in which: R is hydrogen, or R is one or more alkyl, substituted or unsubstituted aralkyl, alkoxy, carboxyl, nitro, cyano, trifluoromethyl, acyl, alkyl sulfonyl, aryl sulfonyl, or halogen groups, or R is the atoms necessary to form a substituted or unsubstituted benzo group; A is (CH2)n; where n is 1–5; preferably 2–4; Y is O, S, NR?, or C(R?)2, where R? is hydrogen or alkyl; preferably methyl; Z is hydrogen, halogen, alkyl, substituted or unsubstituted aralkyl; substituted or unsubstituted aroxyl, substituted or unsubstituted thioaroxyl, or substituted or unsubstituted diphenylamino; m is zero or one; and X is a cation, preferably sodium, potassium, lithium, ammonium, or substituted ammonium.

Abstract: A polymerizable lithographic printing plate precursor comprising a support having in order thereon, a polymerizable photosensitive layer and a protective layer containing (A) polyvinyl alcohol and (B) a polyoxyethylene castor oil ether surfactant.

Abstract: A photolithographic method of making an information storage device having different storage characteristics at a plurality of discrete memory locations thereon, comprises the steps of: (a) providing a substrate having a surface portion, said surface portion having a linking group coupled thereto or charge storage group coupled thereto, said linking group or charge storage group having a photocleavable protecting group thereon; (b) exposing at least one first discrete segment of said surface portion to radiant energy sufficient to cleave said protecting group from said linking group or charge storage group and generate a deprotected group, so that said group is deprotected in at least one first discrete memory location and preferably said group remains protected in at least one second discrete memory location. Additional groups are then coupled to the deprotected group as desired. Products produced by such methods are also described.

Abstract: The present invention provides a planographic printing plate precursor comprising a photosensitive layer on a support, the photosensitive layer including an infrared absorbent, a radical polymerization initiator and a radical polymerizing compound, the photosensitive layer being recordable with irradiation with an infrared ray, and being at least one of soluble and dispersible in water.

Abstract: The present invention relates to a paste composition, including a bonding agent charged with a metallic powder, to be used in a prototyping procedure, a procedure for obtaining metallic products from said composition, and a metallic product obtained from said procedure. The composition is characterized by the fact that it includes: a bonding agent comprised of at least one photopolymerizable resin, with a viscosity of less than 4000 mPa.s, measured at 25° C., a photoinitiator, in a concentration greater than 0.2% by mass with respect to the mass of the resin, and a metallic powder in a volumetric concentration greater than 40% with respect to the composition, with said composition having a minimum reactivity on the order of 5 mm3/s per watt of lighting power.

Abstract: An image recording material comprising (a) an infrared ray absorber and (b) a polymer to lower a dynamic coefficient of friction to from 0.38 to 0.60, which can undergo image formation upon exposure with infrared laser; or a long-chain alkyl group-containing polymer having a reduction rate of coefficient of friction to a base polymer of from 0.5 to 0.97, the polymer being a copolymer of a long-chain alkyl group-containing monomer having 6 or more carbon atoms and a hydrophilic monomer.

Abstract: A positive working printing plate precursor is disclosed which comprises a hydrophilic support and a coating provided thereon which comprises in the order given a first layer containing an oleophilic resin soluble in an aqueous alkaline developer and a second layer comprising a water repellent-compound. Furthermore, the coating comprises an infrared absorbing dye containing a polysiloxane group providing a printing plate precursor with high sensitivity.

Abstract: Thermally imageable elements useful as on-press developable lithographic printing plate precursors are disclosed. The elements comprise a substrate and a layer of an imageable composition over the substrate. The imageable composition comprises a photothermal conversion material, particles of a polyurethane polymer, and, optionally, a water soluble polymer. The polyurethane polymer comprises urethane linkages in the main chain, but does not comprise side chain urethane groups.

Abstract: A lithographic printing plate for infrared laser is provided which shows an excellent coated surface state and an excellent stability with time against scratch, and which has a heat-sensitive layer containing the following (A) to (D): (A) a substance which absorbs a light to generate heat; (B) an alkaline aqueous solution-soluble resin having phenolic hydroxyl groups; (C) a polymer containing as a polymerizable component (meth)acrylate monomer having within the molecule 2 or 3 perfluoroalkyl groups containing 3 to 20 carbon atoms; and (D) a fluorine-containing polymer containing at lease a specific monomer as a copolymerizable component.

Abstract: A presensitized lithographic printing plate comprises a hydrophilic support and an image-forming layer. The image-forming layer contains microcapsules. The microcapsules consist of a shell and a core. The shell comprises a polymer. The polymer has a decomposition temperature in the range of 150 to 280° C. The core comprises a polymerizable compound.

Abstract: Aqueous-based thermally sensitive emulsions and photothermographic imaging materials include photosensitive silver halide grains that comprise at least 15 mol % iodide based on total silver in the grains and are doped with bismuth (+3). These materials have increased photographic speed especially in the infrared region of the electromagnetic spectrum.

Abstract: The present invention provides a thermally sensitive composition that may be coated as a water-borne material onto a substrate to yield a printing plate precursor having an imageable coating. The thermally sensitive composition comprises a sulfated phenolic resin. The sulfated phenolic resin may be a sulfated novolak resin or a sulfated resole resin, for example. The thermally sensitive composition may include a water-soluble binder, such as polyvinyl pyrrolidone, and a radiation-absorbing component. The invention also provides a printing plate precursor that is developed in water after imaging. The precursor does not require chemical development with a developing solution containing organic solvents or inorganic additives. The imaged precursor is on-press-developable when used with a fountain solution. Methods for making and using the precursor are also provided.

Abstract: A donor element adapted for use in making an OLED device including a donor support element; a light-absorbing layer disposed over the donor support element, which in response to light, produces heat; a host material layer disposed over the light-absorbing layer; and a dopant layer disposed over the host material layer such that when the donor element is placed in a transfer relationship with the OLED device and when light is absorbed by the light-absorbing layer, heat is produced that causes the vaporization transfer of host materials and dopant materials from the light-absorbing layer to cause at least partial mixing in the OLED device.

Abstract: The present invention provides an initiator system including an infrared-absorbing compound that exhibits an electronic transition band in the near-infrared region, an initiator, and a metallocene compound. Upon exposure to infrared radiation, the initiator system is capable of producing radicals sufficient to initiate a photopolymerization reaction. Suitable infrared-absorbing compounds include indocyanine dyes, for example. Trihalomethyl triazine compounds and onium compounds are suitable initiators. Suitable metallocene compounds include ferrocenes and titanocenes. The present invention also provides an infrared-sensitive composition including an ethylenically unsaturated polymerizable component, an infrared-absorbing compound that exhibits an electronic transition band in the near-infrared region, an initiator, and a metallocene compound. The infrared-sensitive composition provides improved photospeed and sensitivity in some embodiments.

Abstract: A photosensitive element for use as a photopolymer printing plate comprising a support, a layer of a photopolymerizable material on the support, and an infrared ablation layer which is ablatable by infrared radiation and substantially opaque to actinic radiation on the photopolymerizable material. The infrared ablation layer comprises at least one infrared absorbing material, a radiation opaque material, and at least one binder which is substantially incompatible with low molecular weight materials in the photopolymerizable layer. The infrared ablation layer is tack-free or substantially tack-free on the photopolymerizable layer. The infrared ablation layer is ablatable from the surface of the photopolymerizable layer upon exposure to infrared laser radiation.

Abstract: The invention provides near infrared absorbing materials showing high light-to-heat conversion efficiency and high sensitivity to lasers whose emission bands are within the range of 750 nm to 900 nm, original plates for direct printing plate making, and novel compounds which can be applied to such absorbing materials and plates. The compounds are polymethine compounds of the general formula (I) A detailed description of general formula (I) may be found in the specification. wherein R1 represents an alkoxy group which may be substituted; R2 represents an alkyl group which may be substituted; R3 and R4 each represents a lower alkyl group or R3 and R4 taken together represent a ring; X represents a hydrogen atom, a halogen atom or a substituted amino group; Y represents an alkoxy group which may be substituted or an alkyl group which may be substituted; Z represents a charge neutralizing ion.