Abstract: A thermally sensitive imaging member can be imaged using thermal energy such as from an IR-emitting laser and then used for lithographic printing. The imaging member includes a support having an ink-repellant subbing layer and a thermally sensitive, ink-repellant surface imaging layer. Imaging causes a “switching” in the exposed surface regions to a more oleophilic or ink-accepting nature. Post-imaging processing is unnecessary in this imaging system. The surface imaging layer includes a thermally sensitive copolymer of silicone “soft” segments and thermally sensitive “hard” segments as well as a photothermal conversion material that is IR radiation sensitive.

Abstract: A radiation-sensitive composition comprises: (i) at least one component capable of absorbing IR radiation; and (ii) a diazonium polycondensation product soluble in an organic solvent; with the proviso that the composition does not contain components capable of reacting with decomposition products produced from IR radiation exposure of the diazonium polycondensation product. The composition may additionally comprise a polymeric binder of the type useful for conventional negative-working printing plates. The composition is suitable for preparing thermally imageable printing plate precursors and printing plates and may also be used in a method for providing an image on such plate precursors and printing plates.

Abstract: A heat mode type lithographic printing plate precursor which can be directly mounted on a printing press without development processing after scanning exposure for a short time to conduct plate-making, has excellent press life and also gives few print stains onto a printed face, which comprises a substrate having provided thereon an image recording layer containing fine light-heat convertible particles which are coated with a hydrophilic material, the layer being made hydrophobic by the action of heat.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, can be prepared using a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer that comprises recurring units comprising quaternary ammonium carboxylate groups. These quaternary ammonium carboxylate groups include at least one substituted-alkylene(C1-C3)-phenyl group. The imaging member can also include an infrared radiation sensitive material to provide added sensitivity to heat that can be supplied by laser irradiation in the IR region. The heat-sensitive polymer is considered “switchable” in response to heat, and provides a lithographic image without wet processing.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, can be prepared using a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer that comprises recurring units comprising quaternary ammonium carboxylate groups. The imaging member can also include an infrared radiation sensitive material to provide added sensitivity to heat that can be supplied by laser irradiation in the IR region. The heat-sensitive polymer is considered “switchable” in response to heat, and provides a lithographic image without wet processing.

Abstract: A direct drawing type lithographic printing plate precursor comprising a water-resistant support having provided thereon an image-receiving layer comprising inorganic particles and a binder resin, wherein the inorganic particles comprise at least one kind of particles selected from: (i) metal oxide particles having an average particle size of from 0.01 to 5 &mgr;m and comprising a metal atom selected from Mg, Ba, Ge, Sn, Zn, Pb, La, Zr, V, Cr, Mo, W, Mn, Co, Ni and Cu; and (ii) double oxide particles having an average particle size of from 0.01 to 5 &mgr;m and comprising at least one metal atom selected from Mg, Al, Si, Ti, Zr, Cr, V, Mo, Sn, W and Nb, and wherein the binder resin comprises a complex comprising: a resin containing a bond in which a metal atom is connected with an oxygen atom; and an organic polymer containing a group capable of forming a hydrogen bond with the resin and at least one polar functional group selected from a carboxy group, a sulfo group and a phosphono group.

Abstract: A method of producing a printing plate comprises:

Abstract: According to the present invention there is provided a heat-sensitive imaging element for making lithographic printing plates. The heat-sensitive imaging element comprises an image-forming layer comprising hydrophobic thermoplastic polymer particles having a specific particle size and polydispersity for obtaining printing plates with an improved sensitivity, excellent developability, high throughput and less scumming.

Abstract: Provided is a lithographic printing machine comprising a plate cylinder for imaging, a blanket cylinder, an impression cylinder, and a film-coating unit, a film-hardening unit, an imaging unit and a cleaning unit each unit of which is adjacent to the plate cylinder for imaging, wherein an image-forming layer containing a polymer having a functional group which is crosslinked by light or heat before imaging and a functional group which is converted from hydrophilic to hydrophobic by the heat generated by infrared ray irradiation is formed by the coating unit. A lithographic printing method using the lithographic printing machine is also provided.

Abstract: In order to simplify the sequence of creating a mask, in particular for producing a printing plate, and at the same time to improve the quality of the printing plate produced by means of a mask, the use of laser-induced thermal transfer is provided. The structure information is applied directly to the surface of a printing plate carrier during the creation of a mask, by means of a thermal transfer film and a laser image-setting unit, so that by means of the structure information applied, differentiation with regard to image points and non-image points can be carried out directly in order to produce a printing plate.

Abstract: A method of producing a lithographic printing plate which comprises subjecting a printing plate precursor comprising a support having a metallic compound layer which has a photo-catalytic property and a hydrophilic surface and bears light-heat convertible minute particles on the surface thereof to imagewise irradiation of heat mode to convert polarity of the metallic compound layer, thereby forming an imagewise hydrophobic region. The lithographic printing plate can be repeatedly employed.

Abstract: A planographic printing member precursor comprises a first component, for example a hydroxy group containing polymer, and a second component which may be a siloxane or a compound of general formula (I), wherein M represents a silicon or a titanium atom and each of R1, R2, R3 and R4 is independently selected from hydrogen or halogen atoms; a hydroxy group; an optionally substituted alkyl, alkenyl or alkynyl group; an optionally substituted alkoxy group; or an optionally substituted saturated or unsaturated cyclic or heterocyclic group. On exposure, the second component reacts with the first component to define an oleophobic/hydrophilic material in exposed areas and in non-exposed areas the second component is removed, on processing of the precursor.

Abstract: A method is disclosed for removing ink accepting areas of a printing surface of a lithographic printing master by treatment with an atmospheric plasma. Preferably, the plasma is directed to the printing surface as a plasma jet while the printing master is mounted on the plate cylinder of a printing press. The method enables to clean a support of a printing master and then reuse the cleaned support for making another printing master. Preferably, all the following steps are performed on-press: (i) making an imaging material by providing a support with an image recording layer; (ii) making a printing master having a printing surface comprising ink accepting areas by image-wise exposing and optionally developing the imaging material; (iii) starting a pressrun; (iv) a cleaning step using an atmospheric plasma and then repeating steps (i) to (iv).

Abstract: A process for making lithographic sheet material suitable for imaging by laser radiation. A metal substrate is electrocoated in a bath containing a polymeric resin and laser-sensitive particles, thereby depositing a laser ablatable layer on a principal surface of the metal substrate. In one embodiment, the laser-ablatable layer is treated with a corona discharge for a time sufficient to render the layer non-ink wettable. In other preferred embodiments, the laser-ablatable layer is overcoated with an overlayer such as a non-ink wettable silicone layer or a water-wettable layer comprising an organophosphorus polymer, preferably a copolymer of acrylic acid and vinylphosphonic.

Abstract: A method of making a lithographic printing master is disclosed which comprises the steps of

Abstract: According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of applying a first magnetic field to a dry, light absorbing powder, which comprises a magnetic material and a hydrophobic thermoplastic binder, thereby coating said powder on a surface of a metal support; image-wise exposing to light the powder in contact with the surface of the metal support, thereby increasing the adhesion of the powder to the surface of the metal support, without substantially ablating the powder; and removing the non-exposed magnetic powder from the surface of the metal support under action of a second magnetic field with a polarity substantially opposite to the first magnetic field.

Abstract: A planographic printing member precursor comprises a first component, for example a hydroxy group containing polymer, and a second component which may be a siloxane or a compound of general formula (I): wherein M represents a silicon or a titanium atom and each of R1, R2, R3 and R4 is independently selected from hydrogen or halogen atoms; a hydroxy group, an optionally substituted alkyl, alkenyl or alkynyl group; an optionally substituted alkoxy group; or an optionally substituted saturated or unsaturated cyclic or heterocyclic group. On exposure, the second component reacts with the first component to define an oleophobic/hydrophilic material in exposed areas and in non-exposed areas the second component is removed, on processing of the precursor.

Abstract: A heat-sensitive precursor of lithographic printing plates, which comprises a hydrophilic layer provided on a substrate having an ink-receptive surface or coated with an ink-receptive layer; the printing plate precursor further having a water-soluble overcoat layer on the hydrophilic layer, and the hydrophilic layer being a three-dimensionally cross-linked hydrophilic layer, the heated area of that is easily removed by a fountain solution or ink when subjected to printing operations.

Abstract: A method for driving a printing press having, (i) an impression cylinder, (ii) at least one cylinder group having (a) a blanket cylinder, (b) a printing form cylinder, and (1) an imaging device, (2) an inking unit, and (3) an inherent drive system, all for said printing form cylinder, (iii) a sheet feeding device, (iv) a sheet delivering device, (v) a drive wheel train connecting the cylinders and the inking unit, and (vi) optionally a main motor drive, the method comprising detaching the printing form cylinder from the drive wheel train, driving the printing form cylinder by the inherent drive system at imaging speed during image formation, and re-attaching the printing form cylinder after image formation to the drive wheel train in an operating phase position.

Abstract: A heat-sensitive composition, for example a coating on a lithographic printing plate, comprises a carboxylic acid derivative of a cellulosic polymer. The composition may contain a radiation absorbing compound and suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the composition imagewise. The presence of the cellulosic polymer enhances resistance to certain organic liquids.

Abstract: An off-press plate-making apparatus is provided which comprises means for removing the lithographic image from the substrate of a used printing master and means for recoating the recycled substrate with a new image-recording layer. The off-press cleaning and recoating of the substrate provides a short press down-time. The recoated substrate forms an imaging material which can be exposed either on-press in a digital press comprising an integrated exposure apparatus or off-press in an exposure apparatus, which can be integrated in the plate-making apparatus or mechanically coupled thereto.

Abstract: A heat-mode exposable imaging material is disclosed which is suitable for making a driographic printing master capable of accepting ink at exposed areas, said material comprising (i) a first layer containing more than 50% by weight of carbon or of an organic light absorbing compound, and (ii) an ink-abhesive second layer underlying said first layer, characterised in that said first layer is removable at non-exposed areas by starting a pressrun without substantially removing said second layer. In a preferred embodiment, the material comprises a support, a silicone coating and a surface coating which consists essentially of carbon, soot or graphite. After heat-mode exposure, the material is ink accepting at exposed areas and the surface coating is removed at non-exposed areas during the start of a pressrun, thereby revealing the silicone coating.

Abstract: Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal base supports, and amenability to imaging with low-power lasers that need not impart ablation-inducing energy levels. A representative printing member has a hydrophilic metal substrate and, thereover, first and second layers. The first layer has a thickness and an exposure surface and comprises a material that absorbs imaging radiation. The second layer overlies the first layer and is oleophilic and substantially transparent to imaging radiation. Exposure to imaging radiation causes the first layer and the substrate to irreversibly detach without substantial ablation, thereby facilitating removal, by subjection to the cleaning liquid, of the first and second layers where detachment has taken place.

Abstract: Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal base supports, and amenability to imaging with low-power lasers that need not impart ablation-inducing energy levels. A representative printing member has a topmost layer that is ink-receptive and does not significantly absorb imaging radiation, a second layer thereunder that is hydrophilic and does absorb imaging radiation, and a metal substrate under the second layer. The printing member is selectively exposed to laser radiation in an imagewise pattern, and laser energy passes substantially unabsorbed through the first layer and is absorbed by the second layer. Heat builds up in the second layer sufficiently to detach the first layer, which is formulated to resist reattachment. But the first layer and, more significantly, the third layer act to dissipate heat from the second layer to prevent its ablation.

Abstract: A printing plate useful in lithographic printing is prepared by the process comprising: (a) applying an alkali soluble composition comprising at least one polymer composition to a hydrophilic surface on a substrate to provide the surface face with at least one layer which is alkali soluble at a pH in the range of about 6.0 to 14.0; (b) imaging the coated substrate electrostatically with a toner composition; (c) heating the imaged substrate a first time to a temperature greater than the glass transition temperature of the toner composition; (d) contacting the imaged substrate with an aqueous alkaline solution having a pH in the range of about 6.0 to about 14.0; and (e) heating the imaged substrate a second time to a temperature greater than the glass transition temperature of the toner composition. This printing plate is capable of long runs on press with good image quality and advantageously minimizes the occurrence of undesirable background toner “specking” on press.

Abstract: A heat-sensitive lithographic printing plate precursor which comprises a substrate having thereon an anodic oxidation layer, with the printing plate precursor comprising a hydrophilic layer containing at least one kind of fine particles selected from the group consisting of heat-fusible hydrophobic thermoplastic fine particles, finely divided polymers having thermally reactive functional groups and microcapsules in which compounds having heat-reactive functional groups are encapsulated, and with the anodic oxidation layer having a surface over which micropores having an average pore size of 6 to 40 nm are uniformly distributed.

Abstract: According to the present invention there is provided a method for making a negative working non-ablative imaging material, suitable for making a lithographic printing plate, including the steps of applying a dry powder containing at least a compound capable of converting light into heat and an organic compound on a surface of a non-electrically charged metal support, characterized in that the amount of organic compound in the powder ranges from 51 to 95% by weight.

Abstract: Provided is a lithographic printing plate comprising a support substrate having disposed thereon an ablative-absorbing layer and, optionally, a durable, ink-accepting surface layer that is not ablative-absorbing. The ablative-absorbing layer may contain a high weight per cent of an organic sulfonic acid component. The printing plate may further comprise a hydrophilic polymeric layer interposed between the ablative-absorbing layer and the substrate. The printing plate also comprises a primer layer underlying the ablative-absorbing layer with an adhesion-promoting agent, such as a zirconium compound, present in the primer layer. Also provided are methods of preparing such lithographic printing plates, and methods of preparing imaged lithographic printing plates from such lithographic printing plates by imagewise exposure to a laser and a subsequent cleaning step with water or with a cleaning solution.

Abstract: Provided are methods of preparing a positive-working lithographic printing plate, which methods comprise the steps of (a) providing a positive-working lithographic plate, such as a wet lithographic plate, imageable by laser radiation, which plate comprises an ink-accepting layer, such as an ink-accepting surface layer, (b) imagewise directing a source of radiation to image a first region of the ink-accepting layer in a desired pre-exposed pattern, and (c) imagewise directing laser radiation to image a second region of the ink-accepting layer in a desired final printing pattern, wherein at least a portion of the first region is not capable of being imaged during step (c) due to positioning of the plate during the exposure to the laser radiation and wherein the portion of the first region comprises areas which are capable of being inked and transferring ink to a receiver substrate during lithographic printing. Also provided are imaged lithographic plates prepared by such methods.

Abstract: Lithographic printing is performed with printing members having a hydrophilic-surfaced metal support and a polymeric layer thereover. The polymeric layer absorbs imaging radiation and is soluble in a liquid to which ink will not adhere (e.g., fountain solution). Ordinarily, the polymeric layer is mostly removable by fountain solution. In response to absorbed imaging radiation, however, it may become permanently bound to the metal support so as to resist removal, serving as an ink-carrying oleophilic layer during printing.

Abstract: A thermal lithographic printing plate, which can be imaged by thermal energy typically by imagewise exposure with an infrared emitting laser, a thermal printing head, etc., is made up of a hydrophilic substrate, and a composite layer structure composed of two layer coatings. Preferably, the first layer of the composite is composed of an aqueous developable polymer mixture containing a photothermal conversion material which is contiguous to the hydrophilic substrate. The second layer of the composite is composed of one or more non-aqueous soluble polymers which are soluble or dispersible in a solvent which does not dissolve the first layer. The plate is exposed with an infrared laser or a thermal print head, and upon aqueous development of the imaged plate, the exposed portions are removed exposing hydrophilic substrate surfaces receptive to conventional aqueous fountain solutions. The unexposed portions contain the ink-receptive image areas.

Abstract: A thermal lithographic printing plate, which can be imaged by thermal energy typically by imagewise exposure with an infrared emitting laser, a thermal printing head, etc., is made up of a hydrophilic substrate, and a composite layer structure composed of two layer coatings. Preferably, the first layer of the composite is composed of an aqueous developable polymer mixture containing a solubility inhibiting material and a photothermal conversion material which is contiguous to the hydrophilic substrate. The second layer of the composite is insoluble in the aqueous solution, is ink receptive, and is composed of one or more non-aqueous soluble polymers which are soluble or dispersible in a solvent which does not dissolve the first layer. The plate is exposed with an infrared laser or a thermal print head, and upon aqueous development of the imaged plate, the exposed portions are removed exposing hydrophilic substrate surfaces receptive to conventional aqueous fountain solutions.

Abstract: A process for treating the periphery of an unexposed photosensitive resin plate, which comprises irradiation of light having a wavelength of not longer than 300 nm on the periphery of the unexposed photosensitive resin plate until the periphery is free of stickiness. The process of the present invention solves problems such as sticking of the peripheral resin of unexposed plates to packages, sticking of unexposed resin to a working table, exposure table or vacuum adhesion sheet, sticking of dust, and so on on the periphery of unexposed plates, and sticking of unexposed resin to hands when handling, while eliminating all defects in handling during the steps of making printing plates.

Abstract: This invention provides a directly imageable planographic printing plate precursor with excellent image reproducibility without requiring any complicated process after irradiation with a laser beam. To solve the above problem, this invention is constituted as describe below. A directly imageable waterless planographic printing plate precursor, in which at least an ink acceptable layer and a silcone rubber layer are laminated in this order on a substrate, wherein when the printing plate precursor is measured by TG-GC/MS in a hellium current at a heating rate of 10° C./min, a decomposition product is generated in a temperature range of 100° C. to 200° C. by 0.001 g/m2 to 1 g/m2 per plate area.

Abstract: A printing system which uses a single-layer printing member coated on to a cylinder is provided. For waterless offset application, the single-layer printing member may comprise an oleophobic imaging layer containing an oleophobic resin, coated on an oleophilic cylinder. The single-layer printing member is composed of a resin having either oleophobic or oleophillic properties, to which an infrared absorbing component or components may be added.

Abstract: A process is provided for a printing form for wet offset printing. A printing style is formed on an ink-transferring surface of the printing form (12) by forming ink-absorbing and ink-repelling areas. For illustration, the ink-transferring surface is wetted with a moistening agent. The areas of the moistened surface that are to be made into ink-absorbing areas are dried in a specific manner, and a material that absorbs printing ink is uniformly applied to the ink-transferring surface with the still dry areas. It is also possible to uniformly apply to the ink-transferring surface first a flowable material that absorbs printing ink, to dry the areas to be made into ink-absorbing areas in a specific manner, and to remove it from the areas to be made into ink-repelling areas by means of moistening agent.

Abstract: An image forming apparatus comprises: an image forming body comprising a substrate and a self-assembling compound adsorbed to a surface of the substrate to form a self-assembling monomolecular film; a first desorbing device for selectively desorbing at least a part of the self-assembling compound forming the self-assembling monomolecular film from the surface of the image forming body, so as to provide the surface of the image forming body with a desorbed face and an undesorbed face which have wettabilities different from each other; a developing device for supplying the surface of the image forming body with ink which preferentially attaches to one of the desorbed face or undesorbed face; and a transfer device for transferring to a recording medium the ink attached to the surface of the image forming body. In this apparatus, a printing plate can easily be formed and erased, and the same printing plate can be used repeatedly.

Abstract: A printing press includes a plate cylinder, a plate making unit, and a detection unit. The plate cylinder is rotatably supported by a frame and has an outer surface on which a plate is mounted. The plate making unit is supported to be movable between an operative position where plate making is performed and a wait position to escape from the operative position to perform plate making for the plate. The plate making unit has an exposure unit and a support mechanism for supporting the exposure unit to be movable in an axial direction of the plate cylinder. The exposure unit has a head which irradiates the plate with a laser beam to print an image on the plate. The detection unit detects a position of the exposure unit with reference to the frame.

Abstract: A printing machine includes a printing form, an optical imaging unit for directly imaging the printing form, and an inking unit for inking the printing form, the printing form having a surface formed of a material with wetting properties reversibly changeable between a state with a very small contact angle and a state with a relatively large contact angle, the state with a small contact angle being achievable by action of light having a wavelength shorter than a material-specific wavelength, and a cleaning device for cleaning the surface of the printing form; and a printing process performed with the printing machine.

Abstract: A lithographic printing member comprises a base material and a coating provided thereon. The coating having one or more layers containing magnetic particles. Printing processes and products are also disclosed.

Abstract: A method for preparing a printing form and a method of printing are disclosed. A coating of a radiation sensitive ink on a lithographic support having a hydrophilic surface is imaged. The unexposed areas of the coating are removed to produce a printing form, which is used for printing. Preferably, the same radiation sensitive ink is used for printing as is used in the coating, and, preferably, the desired printing run length is predetermined and the thickness of the coating determined according to the desired run length.

Abstract: The effects of interfacial transition between organic and inorganic layers of a lithographic printing member are ameliorated by incorporating an inorganic component within the matrix of the organic layer. In a first aspect, a lithographic printing plate having adjacent organic and inorganic layers is fabricated by depositing a curable polymer, softening the polymer, and integrating an inorganic material therewith. The polymer is then cured to immobilize the integrated deposition material, and the desired inorganic layer is applied over the deposited inorganic material (and any exposed portions of the polymer). In a second aspect, a graded structure is built up on a substrate in successive deposition steps. Both polymer precursors and an inorganic filler material are deposited in stages, with each stage containing a desired ratio of polymer to filler.

Abstract: A printing system which uses a single layer printing member coated on to a cylinder is provided. For waterless offset application, the single layer printing member consists of an oleophobic imaging layer containing an oleophobic resin, coated on an oleophillic cylinder. For wet application, the single layer may either be hydrophilic, coated on a oleophillic cylinder; or vice versa. The single layer printing member is composed of a resin having either oleophobic, hydrophilic or oleophillic properties, to which an infra red absorbing component or components may be added.

Abstract: A structure for pattern formation adapted for optically forming a pattern, characterized by comprising: a photocatalyst-containing layer provided on a substrate, the photocatalyst-containing layer containing a material of which the wettability is variable through photocatalytic action upon pattern-wise exposure.

Abstract: A substrate is coated with a first material which is soluble in a first solvent, whereupon a second material which is strongly adherent to the first material and insoluble in the first solvent is selectively applied by an ink jet printer. The substrate is then developed in the first solvent to establish the image. In a preferred embodiment the substrate is hydrophilic, the first material is a negative working photosensitive material, and the second material is a transparent adhesive, which permits curing the first material by exposure to actinic light after the development step. The adhesive is then removed. In an embodiment directed to a waterless plate the substrate includes a surface coating of silicone, and the first material is a primer which promotes adhesion of a second material in the form of an oleophilic adhesive which is selectively applied. The primer is then developed to expose the silicone on the non-image areas.

Abstract: Negative-working and positive-working lithographic plate constructions include a durable hydrophilic layer; a hard, inorganic, oleophilic layer; and a substrate, which may be metal. If a metal substrate is employed, an overlying layer provides sufficient thermal insulation to prevent substantial dissipation of heat—which is necessary to achieve ablation—into the substrate. In the case of oleophilic layers employed in negative-working embodiments, certain ceramic materials are suitable, and an intermediate tying layer may be used to anchor a hydrophilic ceramic layer to the oleophilic layer. In positive-working embodiments, the oleophilic layers may be refractory compounds doped with oleophilic material. An advantage to the latter embodiments is the ability to apply traditional means of correction following imaging.

Abstract: The present invention relates to particular acetal copolymers and radiation-sensitive compositions comprising said copolymers and, inter alia, are excellently suitable for the production of lithographic printing plates. In particular, the invention relates to acetal copolymers containing furylvinylidene, thienylvinylidene or pyrrolylvinylidene.

Abstract: A positive-working lithographic printing plate which is imageable by dual infrared lasers has a substrate which absorbs modulated, imaging infrared laser radiation of one wavelength to heat the substrate and an adjacent coating. The substrate has a coating which is a material which will react and form gaseous reaction products which ablate or propel the coating from the substrate upon reaching a threshold reaction temperature. The coating is transparent to the infrared radiation of the one wavelength and contains a dye which absorbs unmodulated, non-imaging infrared laser radiation of another wavelength to heat the coating. The unmodulated, non-imaging infrared laser radiation heats the coating in the imaged areas to a temperature below the threshold temperature and the heat from the substrate further heats the coating to a temperature above the threshold temperature and ablates the coating in the imaged areas.

Abstract: A direct write lithographic printing plate includes a base layer; a metal light absorbing layer provided over the base layer; and a melanophobic layer provided over the metal absorbing layer and selected to have a thickness which minimizes reflection of light from the metal layer so that light which passes through a selected portion of the melanophobic layer and into the metal light absorbing layer, is absorbed by such metal layer to provide a heat source which causes the removal, at the selected portion, of the melanophobic layer.

Abstract: The invention provides near infrared absorbers showing high light-to-heat conversion efficiency and high sensitivity to laser beams whose emission region is within the range of 750 nm to 900 nm, plates for direct printing plate making, and novel compounds which can be used in such absorbers or plates. The compounds are polymethine compounds of the general formula (I) shown below and the near infrared absorbers comprise the polymethine compounds.