Abstract: A method for preparing a substrate for a planographic printing member is disclosed. A liquid that contains water; a soluble alkali metal silicate, preferably sodium silicate; and a dispersed particulate material is coated on a support, to produce a hydrophilic layer on the support. A layer of image material may be coated over the hydrophilic layer to produce a planographic printing member. In one embodiment the liquid contains a mixture of two particulate materials, preferably alumina and titanium dioxide. The substrate has a surface roughness of about 0.1 &mgr;m to 2 &mgr;m. The substrate is suitable for preparing a planographic printing member processable to a resolution of 10 &mgr;m or less and in which the dots having a roundness of less than 2 are formed.

Abstract: A printing plate is prepared by the process comprising: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising an acidic polymeric compound and a second compound comprising a pyridyl group in non-aqueous solvent, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the costly and time-consuming need of chemical development.

Abstract: A thermally imageable element, useful as a lithographic printing plate precursor is disclosed. The element comprises a hydrophilic substrate; an underlayer comprising a first polymeric material; and an ink-receptive top layer comprising a second polymeric material. Preferably, the top layer comprises a compound that functions as a solubility-suppressing component. The solubility-suppressing component may be a separate dissolution inhibitor compound and/or the second polymeric material may also function as a solubility-suppressing component. On thermal exposure the exposed regions of the top layer becomes more readily soluble in an aqueous developer, allowing the developer to remove the top layer and reveal the surface of the hydrophilic substrate. The lithographic printing plate thus formed has excellent properties, including the absence of sludging of the developer.

Abstract: A method for producing a predetermined resist pattern on e.g. a lithographic printing plate, circuit board or mask, comprises the patternwise exposure to heat of a composition which comprises a novolac resin, a latent Bronsted acid and optionally a pigment. The composition is rendered preferentially soluble to a developer, in the regions which were heated.

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 lithographic imaging member is prepared by applying an ink jetable fluid to a fluid-receiving element that includes a clay-containing fluid-receiving surface layer. This layer also includes a water-soluble binder and a silane hardening agent. The applied fluid is an aqueous solution of a silane having multiple hydroxy, alkoxy or acetoxy groups that is readily absorbed in the clay-containing surface, and dried to provide an oleophilic image.

Abstract: The present invention provides an aluminum alloy support body for a presensitized plate in which the uniformity of the grained surface due to electrochemical etching is further improved, and a method of producing the same. The aluminum alloy support body for the presensitized plate according to the present invention has a composition comprising 0.1 to 0.7% by weight of Fe; 0.01 to 0.2% by weight of Si; 0.005 to 1.0% by weight of one or more rare earth elements; and the balance of Al and unavoidable impurities. In the present invention, the aluminum alloy support body may further contain 0.005 to 0.1% by weight of Ni and 0.005 to 0.3% by weight of one or more rare earth elements. One or more elements of Ce, La and Nd can be selected as the rare earth elements.

Abstract: A positive image can be obtained from a positive-working element that is sensitive to infrared radiation. The element comprises an imaging layer containing an alkali-soluble reactive resin (such as a phenolic resin), an infrared radiation absorbing compound, a thermochemical acid generating compound, and a dissolution inhibitor that has acid-cleavable C—O—C groups. Upon laser exposure, a Bronsted acid is generated which then breaks the bonds of the C—O—C groups, allowing the exposed regions of the reactive resin to be solubilized in an alkaline developer solution.

Abstract: The present invention relates to IR-sensitive compositions containing an initiator system comprising: (a) at least one compound capable of absorbing IR light (b) at least one compound capable of producing radicals and (c) at least one polycarboxylic acid comprising an aromatic moiety substituted with a heteroatom selected from N, O and S and also at least two carboxyl groups wherein at least one of the carboxyl groups is bonded to the heteroatom via a methylene group. These compositions are inter alia extraordinarily suitable for the manufacture of printing plates.

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: A heat imagable article has, in a single layer polymeric coating or in an inner layer of a multi-layer polymeric coating on a substrate, a polymeric matrix material, for example a phenolic resin, and, dispersed therein, polymeric particles, for example of polyethylene or polytetrafluoroethylene. The coating may contain a radiation absorbing compound so that suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the coating imagewise. The presence of the particles increases the physical robustness of the layer.

Abstract: An imagable composition, for example a coating on a lithographic printing plate, comprises a carboxylic acid derivative of a cellulosic polymer and a diazide moiety, and may be imaged in various ways, including by ultra-violet radiation, by infra-red radiation and by heat. The presence of the cellulosic polymer can act to enhance resistance to certain organic liquids and/or to increase operating speed.

Abstract: The invention relates to the use of cationic latex particles that can complex with anionic dyes to provide water fastness and further to provide a medium in which inherently unstable anionic dyes can be brought in close proximity with other anionic components, by complexation to cationic latices, in order to stabilize the anionic dyes especially with regard to light and oxidative degradation. In particular this invention will provide for methods of generating waterfast and improved lightfast ink jet images.

Abstract: An improved hydrophilized substrate for planographic printing is disclosed. The substrate contains a support and a hydrophilic layer over the support. The hydrophilic layer contains titanium dioxide (titania) particles. In one embodiment, the hydrophilic layer contains a mixture of coated and uncoated titanium dioxide particles, and, optionally, alumina particles. A method for preparation of the substrate and a printing member comprising the substrate are also disclosed.

Abstract: Imageable elements useful as lithographic printing members are disclosed. The elements contain a substrate, an underlayer, and a top layer. The underlayer contains a combination of polymeric materials that provides resistance both to fountain solution and to aggressive washes, such as a UV wash. The underlayer can be used in either thermally imageable or photochemically imageable elements.

Abstract: There is described a method of preparing a lithographic plate which comprises coating on a lithographic support having a hydrophilic surface a layer of a radiation sensitive coating, imaging the coating then acting on the plate while on the press with aqueous fount solution to remove the unexposed areas of the coating, to reveal the hydrophilic surface of the plate and to leave an ink receptive image, wherein the radiation sensitive coating comprises a diazo salt of formula (I): wherein R1 is an anion, R2 and R3 represent optional substitution, R4 is —N— and —S— and R5 is a group which, after exposure of the plate renders the residue of the diazo salt oleophilic and fount solution insoluble.

Abstract: Polymeric compounds for lithographic printing plates, especially plates for use in printing utilizing UV curable inks, may include a structural unit (I) 1

Abstract: Thermally imageable lithographic printing plate precursors and heat-sensitive compositions for use in these printing plate precursors are disclosed. The compositions contain an aqueous developer soluble polymer, such as a phenolic resin; a compound that reduces the aqueous developer solubility of the polymer; and optionally, and infrared absorber. Examples of compounds that reduce the aqueous developer solubility of the polymer are those that contain at least one quarternized nitrogen atom, such as quinolinium compounds, benzothiazolium compounds, pyridinium compounds, and imidazoline compounds. On thermal imaging, the irradiated areas become more soluble in the aqueous developer and can be removed to form a positive image.

Abstract: A printing plate precursor for direct receipt of an image-wise applied ink receptive layer the precursor having a desorbable surfactant adsorbed on at least one surface in an amount effective to improve the resolution of the subsequently image-wise applied ink receptive layer. The printing plate precursor can be used to prepare a printing plate having improved resolution. The printing plate may be prepared by (a) applying a desorbable surfactant to at least one surface of a printing plate substrate, (b) removing non-adsorbed surfactant from the surface, (c) applying a fluid composition containing an ink receptive material onto at least a portion of the surface in the form of a desired image, thereby providing an ink receptive image layer; and (d) removing the desorbable surfactant from any area of the surface which does not form part of the desired image.