Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, comprises latex polymer-carbon black composite particles. Such imaging members can be prepared with a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer having ionic moieties and the latex polymer-carbon black composite particles as a photothermal conversion material. The latex polymer-carbon black composite particles can be formulated in water or water-miscible solvents without agglomeration with other components such as charged polymers.

Abstract: A waterless planographic printing plate precursor which has a support member, a light-to-heat conversion layer for converting laser light to heat, and a silicone rubber layer. The light-to-heat conversion layer is contains at least one kind of polyurethane having at least one carboxyl group, and at least one light-to-heat conversion substance.

Abstract: The present invention includes an imageable element, which includes a sheet substrate, an imaging layer and a silicone layer, which comprises a crosslinked silicone polymer. The crosslinked silicone polymer is the curing product of a vinyl functional polysiloxane copolymer and a hydrosiloxane compound. The curing is catalyzed by a platinum carbonyl complex. Upon imagewise exposure and development, an imaged element is obtained, which is mounted on a dry printing press containing lithographic ink and used to produce printed stock.

Abstract: An improved offset printing press has a single plate blanket image (PBI) cylinder for holding an image formed on a thin film printing plate affixed thereto. The plate may be from 0.5 to 25 microns thick and has a thin layer of ink repelling material coated thereon. The plate is imaged, after being affixed to the PBI cylinder, by ablating selective portions of the ink repelling coating. The PBI cylinder is constructed to hold the printing plate by vacuum techniques, and apparatus to load and unload the plate is associated with the PBI cylinder. Because of the thinness of the printing plate, the PBI cylinder is a compliant surface, capable of printing on an inelastic media covered impression cylinder. In addition, unique inking apparatus is provided to transfer ink to the imaged printing plate. Variations of the press include a four color press utilizing a single PBI cylinder.

Abstract: A hydrophilic layer and an overcoat layer are provided in this order on a heat-sensitive layer having an ink receiving surface, so as to form an original (plate) for a lithographic printing plate. The overcoat layer can be removed during printing. A system capable of forming an inorganic hydrophilic matrix by sol-gel conversion is provided in the hydrophilic layer. Adhesion between the heat-sensitive layer and the hydrophilic layer decreases in a heated region through image processing. Emulsion ink is supplied to the plate surface during printing, whereby the overcoat layer and the hydrophilic layer at an image portion are removed with a hydrophilic component of the emulsion ink. Thus, with a heat-sensitive original that can be subjected to heat-mode prepress using laser exposure, good printed matter can be stably obtained, irrespective of balance between image and non-image portions, without using wetting water.

Abstract: Lithographic printing plates having on a hydrophilic substrate an oleophilic photosensitive layer comprising an oleophilic polymer, a free radical polymerizable monomer, and 4-piperonyl-2,6-bis(trichloromethyl)-s-triazine as free radical initiator and/or leucomalachite green as exposure indicating dye; wherein the weight ratio of the monomer to the polymer is larger than 1.0. The plates can be developed with ink and/or fountain solution on a lithographic printing press or with a non-alkaline aqueous developer comprising 60-99% by weight of water and 0.5 to 40% by weight of an alcohol solvent. A photosensitive dye can be added in the photosensitive layer to provide photosensitivity to a specific wavelength between 200 and 1200 nm. Unlike commonly used s-triazine initiator or leuco dye, 4-piperonyl-2,6-bis(trichloromethyl)-s-triazine or leucomalachite green does not insolubilize from the photosensitive layer.

Abstract: A method for forming a dampening-waterless lithographic plate comprising an irradiation step of irradiating a dampening-waterless lithographic blank plate imagewise with a laser beam, the blank plate comprising a support, a photothermal conversion layer provided on the support for converting laser beam energy to heat, and an ink-repellent layer provided on the photothermal conversion layer a first rubbing step of rubbing the surface of the ink-repellent layer without use of a liquid so as to remove at least a portion of the ink-repellent layer in areas irradiated with a laser beam and a second rubbing step of rubbing the surface of the partially removed ink-repellent layer through use of a liquid.

Abstract: Disclosed is a planographic printing plate precursor comprising a support, and provided thereon, an image forming layer, a first outermost layer on the image forming layer side and a second outermost layer on the side of the support opposite the first outermost layer, the first and second outermost layers containing a lubricant component, which is manufactured either by a method comprising the steps of preparing a planographic printing plate precursor comprising a support and provided thereon, an image forming layer so that only the first outermost layer contains a lubricant component and winding the resulting precursor in the roll form, or by a method comprising the steps of preparing a planographic printing plate precursor comprising a support and provided thereon, an image forming layer so that only the second outermost layer contains a lubricant component and winding the resulting precursor in the roll form.

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: There is disclosed a dampening composition for lithographic printing which comprises a (poly) propylene glycol alkyl ether and an ethylene oxide adduct of acetylene glycol.

Abstract: There is provided improvement of a light-heat conversion in a light-stimulated writing method. An image recording body includes an element, which absorbs light (electromagnetic wave), provided in a surface of a recording body 10, or in a recording layer formed on uppermost layer of the recording body having a material exhibiting thermal changeable character of wettability, or in a substrate or an intermediate layer of the recording body. After a liquid is on the recording body 10 by a liquid forming means 3, light-stimulated writing is carried out. When the light-stimulated writing is carried out with light (electromagnetic wave) from a light (electromagnetic wave) source according to image information, an efficiency of light-heat conversion can be enhanced by a light (electromagnetic wave)-absorbing element.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, comprises latex polymer-carbon black composite particles. Such imaging members can be prepared with a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer having ionic moieties and the latex polymer-carbon black composite particles as a photothermal conversion material. The latex polymer-carbon black composite particles can be formulated in water or water-miscible solvents without agglomeration with other components such as charged polymers.

Abstract: The invention relates to a recording material sensitive to IR radiation and having a substrate, a primer layer, an IR-absorbing layer and a silicone layer. The primer layer includes a mixture of an unmodified epoxy resin, an organic polymer having functional groups and a crosslinking agent which reacts with the epoxy resin and the functional groups of the organic polymer. The primer layer preferably contains at least one pigment, in particular inorganic pigments. For the production of a printing plate for waterless offset printing, the recording material is exposed imagewise to IR radiation and is then freed from the ablated layer components by washing with water or an aqueous solution. Preferably the radiation is IR laser radiation. The primer layer according to the invention results in particularly good adhesion of the IR-absorbing layer to the substrate without hindering the removal of the exposed parts of the IR-absorbing layer during development.

Abstract: This patent describes an on-press developable thermosensitive lithographic plate having on a substrate a thermosensitive layer comprising an ethylenically unsaturated monomer, an infrared absorbing dye, and an onium or borate salt free radical initiator. The plate can be imagewise exposed with an infrared laser on a plate exposure device, and then mounted on a lithographic press for on-press development with ink and/or fountain solution and lithographic printing. No regular development process with a liquid developer is needed after exposure. Alternatively, the plate can be imagewise exposed with an infrared laser while mounted on a plate cylinder of a lithographic press, on-press developed with ink and/or fountain solution, and then print images to the receiving sheets.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, has an imaging layer comprised of a thermally sensitive compound and a photothermal conversion material. The thermally sensitive compound comprises a heat-activatable aromatic cyclic sulfonium zwitterion group represented by the following Structure I: wherein Ar is a substituted or unsubstituted aromatic group, X and Y are independently substituted or unsubstituted methylene groups, and n is 1 or 2. The thermally sensitive compound can be a polymer or a small molecule compound. In the imaging member, the thermally sensitive compound reacts to provide increased hydrophobicity in areas exposed to energy that provides or generates heat. The imaging layer is considered “switchable” and can be used to provide a lithographic printing image without traditional alkaline wet processing.

Abstract: A variable data lithographic printing device comprises surrounding a printing cylinder a photosensitive layer coater, an exposure source, optionally a developer, an inking applicator, optionally a transfer system, and optionally an eraser. During printing operation, each surface areas of the rotating cylinder continuously undergo the cycle of coating, imagewise exposure, optionally developing, inking, printing of inked imaging to the receiving medium, and optionally erasing processes. The developing means can be omitted if an ink and/or fountain solution developable photosensitive layer is used. In an alternative design, the cylinder is replaced with a continuous supply of a ribbon with lithographic substrate surface. In another alternative design, the cylinder and the coater are replaced with a continuous supply of a pre-sensitized ribbon comprising on a substrate a photosensitive layer.

Abstract: A heat-sensitive lithographic printing plate precursor is disclosed comprising a polymer which is soluble in an aqueous alkaline solution and which comprises at least one chromophoric moiety having a light absorption maximum in the wavelength range between 400 and 780 nm. Such materials show no dye stain after processing in areas where the coating has been removed by an alkaline developer.

Abstract: This invention is directed to a precursor for preparing a resist pattern by heat mode imaging, the precursor comprising a heat sensitive composition, the solubility of which in an aqueous alkaline developer is arranged to increase in heated areas, and a means for increasing the resistance of non-heated areas of the heat sensitive composition to dissolution in an aqueous alkaline developer (the “developer resistance means”), wherein said developer resistance means comprises one or more compounds selected from the group consisting of: (A) compounds which include a poly(alkylene oxide) unit; (B) siloxanes; and (C) esters, ethers and amides of polyhydric alcohols, wherein said heat-sensitive composition comprises an aqueous alkaline developer soluble polymeric substance (i.e. the “active polymer”) and a compound which reduces the aqueous alkaline developer solubility of the polymeric substance (i.e.

Abstract: This patent describes an on-press developable thermosensitive lithographic plate having on a substrate a thermosensitive layer comprising an ethylenically unsaturated monomer, an infrared absorbing dye, and an onium or borate salt free radical initiator. The plate can be imagewise exposed with an infrared laser on a plate exposure device, and then mounted on a lithographic press for on-press development with ink and/or fountain solution and lithographic printing. No regular development process with a liquid developer is needed after exposure. Alternatively, the plate can be imagewise exposed with an infrared laser while mounted on a plate cylinder of a lithographic press, on-press developed with ink and/or fountain solution, and then print images to the receiving sheets.

Abstract: This invention relates to an imageable element that can be imaged and developed to produce a printing plate. The imageable element comprises a substrate and a radiation-sensitive imageable composition applied to the substrate. The imageable composition comprises (a) a first layer having (i) a photosensitive composition which undergoes a decrease in solubility in developer upon absorption of actinic radiation and (ii) an inhibitor, and (b) a second layer comprising an ink-repellent polymeric material. In one embodiment, the inhibitor is activated by heat or radiation of longer wavelength than actinic radiation. Upon activation, the inhibitor retards the solubility decrease of the photosensitive composition upon absorption of actinic radiation. In another embodiment, the inhibitor initially retards the solubility decrease of the photosensitive composition upon absorption of actinic radiation.

Abstract: According to the present invention there is provided a heat-sensitive material for making lithographic plates comprising in the order given on a support an IR-sensitive oleophilic layer and a cross-linked hydrophilic layer comprising an inorganic pigment and a hardener, characterized in that the ratio of said inorganic pigment over the hardener is comprised between 75/25 and 25/75 by weight.

Abstract: A lithographic printing plate precursor is disclosed which comprises (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon, the coating comprising an oleophilic layer which, upon image-wise exposure to heat or infrared light and subsequent immersion in an aqueous alkaline developer, dissolves in the developer at a higher dissolution rate in exposed areas than in unexposed areas, wherein the oleophilic layer comprises a polymer that is soluble in the developer and an organic dye in a amount sufficient to provide a visible color to the coating, characterized in that said organic dye does not reduce the dissolution rate of the unexposed areas in the developer.

Abstract: A negative-working imaging member can be used as a lithographic printing plate without ablation. The imaging member comprises a support and an imaging layer that includes a dispersion of at least 0.05 g/m2 of a cyanoacrylate polymer that is thermally degradable below 200° C., a photothermal conversion material that is present in an amount to provide a dry weight ratio to the cyanoacrylate polymer of from about 0.02:1 to about 0.8:1, and a hydrophilic binder to provide a dry weight ratio of a hydrophilic binder to the cyanoacrylate polymer of up to 1:1. Thermal imaging energy causes the exposed areas of the imaging layer to adhere to the support while unexposed areas can be readily washed off and/or simultaneously inked for press runs.

Abstract: This patent describes a lithographic printing plate comprising on a substrate a semisolid radiation-sensitive layer capable of hardening upon exposure to a suitable radiation, and a method of imaging such a plate using laser radiation. The utilization of a semisolid radiation-sensitive layer allows faster photospeed and better curing efficiency as desired for digital laser exposure. Several plate designs can be utilized to overcome the tackiness issue associate with the semisolid layer, such as conformally coating the radiation-sensitive layer on a rough substrate and utilizing an overcoat. Plates having an ink and/or fountain solution or dispersible semisolid radiation-sensitive layer can be directly developed with ink and/or fountain solution while solution while mounted on press, with the imagewise laser exposure being carried out on press or off press.

Abstract: According to the present invention there is provided a heat-sensitive non-ablatable wasteless imaging element for providing a lithographic printing plate, comprising on a support a top layer which is capable of forming by image-wise exposure image-wise hydrophobic and hydrophilic areas, characterized in that said imaging element contains an IR-dye capable of changing its optical density by exposure of the imaging element.

Abstract: This patent describes a lithographic printing plate comprising on a substrate a semisolid radiation-sensitive layer capable of hardening upon exposure to a suitable radiation, and a method of imaging such a plate using laser radiation. The utilization of a semisolid radiation-sensitive layer allows faster photospeed and better curing efficiency as desired for digital laser exposure. Several plate designs can be utilized to overcome the tackiness issue associated with the semisolid layer, such as conformally coating the radiation-sensitive layer on a rough substrate and utilizing an overcoat. Plates having an ink and/or fountain solution soluble or dispersible semisolid radiation-sensitive layer can be directly developed with ink and/or fountain solution while mounted on press, with the imagewise laser exposure being carried out on press or off press.

Abstract: There is provided improvement of a light-heat conversion in a light-stimulated writing method.

Abstract: A method for making a lithographic printing plate comprises the steps of imagewise exposing, to a laser beam, a PS plate comprising a substrate, a heat-sensitive layer containing at least one light-heat conversion agent and a binder polymer formed on the substrate and a hydrophilic or lipophobic layer applied onto the heat-sensitive layer; and then removing the hydrophilic or lipophobic layer on the laser-exposed area by developing the imagewise exposed printing plate within 120 seconds from the completion of the laser-exposure to thus give a lithographic printing plate, wherein the developing treatment comprises the step of rubbing the exposed printing plate surface with an abrasion means in the absence of any liquid. This method permits the production of a lithographic printing plate without causing any deterioration of the developing properties of the PS plate even when the imagewise exposed PS plate is developed within a short period of time after the completion of the laser-exposure.

Abstract: According to the present invention there is provided a heat-sensitive material for making lithographic printing plates comprising on a lithographic support an image-forming layer comprising a hydrophilic binder, a cross-linking agent for a hydrophilic binder and dispersed hydrophobic thermoplastic polymer particles, characterized in that said image-forming layer is covered with a layer comprising at least one organic compound comprising cationic groups.

Abstract: Polymer materials are described that undergo a 2-level 3 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 that becomes less hydrophilic upon exposure to thermal energy (e.g.

Abstract: The present invention provides a lithographic printing plate comprising on a roughened substrate a substantially conformal photosensitive layer and a substantially conformal overcoat. The photosensitive layer is substantially conformally coated on the roughened substrate surface and the overcoat is substantially conformally coated on the photosensitive layer surface so that the surface of the overcoat has peaks and valleys substantially corresponding to the major peaks and valleys of the substrate microscopic surface. The lithographic plate of such a configuration can provide no or low tackiness and excellent block resistance, while allowing excellent press durability. For on-press developable lithographic plate, such a plate configuration also allows excellent on-press developability.

Abstract: This patent describes on-press ink and/or fountain solution development of lithographic plates having on a substrate a thermosensitive layer capable of hardening or solubilization upon exposure to an infrared laser radiation. The plate can be imagewise exposed with an infrared laser and then on-press developed with ink and/or fountain solution by rotating the plate cylinder and engaging ink and/or fountain solution roller. The developed plate can then directly print images to the receiving sheets. The imagewise exposure can be performed off the press or with the plate being mounted on the plate cylinder of a lithographic press.

Abstract: An improved offset printing press has a single plate blanket image (PBI) cylinder for holding an image formed on a thin film printing plate affixed thereto. The plate may be from 0.5 to 25 microns thick and has a thin layer of ink repelling material coated thereon. The plate is imaged, after being affixed to the PBI cylinder, by ablating selective portions of the ink repelling coating. The PBI cylinder is constructed to hold the printing plate by vacuum techniques, and apparatus to load and unload the plate is associated with the PBI cylinder. Because of the thinness of the printing plate, the PBI cylinder is a compliant surface, capable of printing on an inelastic media covered impression cylinder. In addition, unique inking apparatus is provided to transfer ink to the imaged printing plate. Variations of the press include a four color press utilizing a single PBI cylinder.

Abstract: The present invention includes an imageable element, which includes a sheet substrate, an imaging layer and a silicone layer, which comprises a crosslinked silicone polymer. The crosslinked silicone polymer is the curing product of a vinyl functional polysiloxane copolymer and a hydrosiloxane compound. The curing is catalyzed by a platinum carbonyl complex. Upon imagewise exposure and development, an imaged element is obtained, which is mounted on a dry printing press containing lithographic ink and used to produce printed stock.

Abstract: Disclosed is a positive or negative lithographic printing plate precursor which can form an image at high sensitivity by heating or heat developed by light-heat conversion, requires no development processing after image writing, has good sensitivity and excellent printing durability, is significantly improved in scumming resistance, and can directly make a plate by operating an infrared laser based on a digital signal, the precursor comprising a polymer compound having a functional group changeable in hydrophilicity by heat, acid or radiation and an under layer with which the polymer compound combined, wherein the polymer compound is a straight-chain polymer compound directly combined at an end of a polymer chain thereof with a surface of the under layer by chemical bonding, or comprises (i) a polymer backbone chemically combined with a surface of the under layer and (ii) a straight-chain polymer compound combined at an and of a polymer chain thereof with the polymer backbone and having a functional group cha

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: According to the present invention there is provided a method for preparing a lithographic printing plate, the method including the steps of (1) providing an imaging element including on a lithographic hydrophilic support as contiguous top layer a heat-sensitive coating including a compound capable of converting light to heat and a compound, which becomes more hydrophilic under the action of heat; (2) imagewise exposing the imaging heat-sensitive composition with a high intensity laser emitting a laser beam with an intensity at the surface of the heat-sensitive composition of tat least 2 mW/&mgr;m2 thereby at least partially removing the heat-sensitive composition to expose at least partially the lithographic support.

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: The present invention relates to a planographic printing plate employed in the field of offset printing, and more particularly, to a preparation method for a printing plate employing a conventional planographic printing original plate with a novel light source. In this method, an image is formed to a planographic printing original plate, in which at least one photosensitive layer sensitive in the region of 300 nm˜450 nm is provided on a substrate, by scan irradiating the plate with high density energy light in the form of the image, and then performing wet development and a post-treatment. This preparation method for the printing plate is characterized in that the output wavelength of the high density energy light is within the range of 300 nm or more, but less than 370 nm, and the high density energy light is high density energy light of the second or third harmonic obtained from a solid-state semiconductor or a solid-state exited by semiconductor.

Abstract: The present invention provides a lithographic printing plate comprising on a roughened substrate a substantially conformal photosensitive layer and a substantially conformal overcoat. The photosensitive layer is substantially conformally coated on the roughened substrate surface and the overcoat is substantially conformally coated on the photosensitive layer surface so that the surface of the overcoat has peaks and valleys substantially corresponding to the major peaks and valleys of the substrate microscopic surface. The lithographic plate of such a configuration can provide no or low tackiness and excellent block resistance, while allowing excellent press durability. For on-press developable lithographic plate, such a plate configuration also allows excellent on-press developability.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, can be prepared with a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer having ionic moieties and an infrared radiation sensitive oxonol dye that has a &lgr;max of greater than 700 nm. The heat-sensitive polymer and IR dye can be formulated in water or water-miscible solvents to provide highly thermal sensitive imaging compositions. In the imaging member, the polymer reacts to provide increased hydrophobicity in areas exposed to energy that provides or generates heat. For example, heat can be supplied by laser irradiation in the IR region of the electromagnetic spectrum. The heat-sensitive polymer is considered “switchable” in response to heat, and provides a lithographic image without wet processing.

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 method of producing a resist pattern on a substrate using a precursor which comprises a coating composition which includes a heat sensitive polymeric substance having functional groups Q thereon (wherein groups Q may be siloxane or optionally substituted fluoroalkyl groups) wherein groups Q cause the polymeric substance to have a reduced adhesive interaction with ink for use in waterless lithographic printing compared to aid polymeric substance in the absence of said groups, the method including the step of causing the patternwise application of heat to said coating composition and optional development thereby to define ink accepting areas in heat exposed areas and non-ink accepting areas in non-exposed areas.

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: Provided is a plate-making method for producing a waterless lithographic printing plate, wherein the method comprises: (I) an exposing step of imagewise exposure of the precursor with a laser with a controlled condition that a portion of a laser-exposed area in a photo-thermal conversion layer in the precursor remains in the photo-thermal conversion layer of the finished printing plate, and (II) a developing step of removing a silicone rubber layer in the laser-exposed area to form an image on the printing plate. The precursor to be processed comprises (A) a support, (B) an undercoat layer formed by applying onto the support a coating liquid that contains a water-soluble or water-dispersible polymer and water as a solvent, and then drying the coating liquid, (C) a photo-thermal conversion layer which comprises polyurethane and a photo-thermal converting agent; and (D) a silicone rubber layer, laminated in that order.

Abstract: A lithographic printing plate comprises on a substrate a thermo-deactivatable photosensitive layer that is photohardenable before exposure to an infrared radiation and can be rendered incapable or having reduced rate of photohardening upon exposure to an infrared radiation. Optionally, an oleophobic top layer may be deposited on the photosensitive layer to form a waterless plate. Such a plate can be imagewise exposed with an infrared laser to thermally deactivate the photosensitive layer in the exposed areas, followed by overall actinic light exposure to harden the infrared laser non-exposed areas. The exposed plate can be developed with a suitable developer to remove the infrared laser exposed areas. A plate with an ink and/or fountain solution soluble or dispersible photosensitive layer of this invention can be developed on a printing press with ink and/or fountain solution during initial press operation.

Abstract: The present invention relates to the use of the frequency-modulated screening or stochastic screening for lightening the printing surfaces, in waterless or wet offset printing techniques. It also concerns the films and plates used in these printing techniques which, in characteristic manner, generate printing surfaces lightened by means of a stochastic screening (or frequency-modulated screening).

Abstract: This patent describes an on-press ink and/or fountain solution developable lithographic printing plates having on a substrate a thermosensitive layer capable of hardening upon exposure to an infrared radiation. The plate can be imagewise exposed with an infrared radiation and then on-press developed with ink and/or fountain solution by rotating the plate cylinder and engaging ink and/or fountain solution roller. The developed plate can then directly print images to the receiving sheets. The imagewise exposure can be performed off the press or with the plate being mounted on the plate cylinder of a lithographic press.

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.