Abstract:
A method to reduce effluence during or immediately after imaging of a printing plate is described. In one embodiment of the invention, the method comprises: (a) applying to a substrate a coating composition comprising a photothermal converter and at least one polymer comprising thiosulfate groups to obtain a coating; and (b) applying a water soluble topcoat to the coating. Preferably, the water soluble topcoat does not comprise a photothermal converter. In another embodiment of the invention, the method comprises applying to a substrate a composition comprising: (a) a photothermal converter; (b) at least one polymer comprising thiosulfate groups; and (c) an additive selected from the group consisting of diazonium, iodonium, copper(I), alkoxypyridinium or maleimide additives.
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:
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:
A lithographic printing plate precursor comprising a hydrophilic support having thereon a heat-sensitive layer containing at least one of a thermoplastic particulate polymer having Tg of not lower than 60° C., a particulate polymer having a heat-reactive group and a microcapsule containing a compound having a heat-reactive group incorporated therein.
Abstract:
Provided is a lithographic printing plate comprising a support substrate having disposed thereon a hydrophilic layer interposed between the substrate and an ink-accepting ablative-absorbing surface layer. The ink-accepting surface layer comprising a one or more polymers and a sensitizer characterized by absorption of laser radiation. The printing plate may also comprise a primer layer underlying the ink-accepting surface layer with an adhesion-promoting agent 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:
A lithographic printing plate precursor comprising: a support having a water-wettable surface; and a heat-sensitive layer comprising a first resin having a hydrogen-donating group and a second resin having a hydrogen-accepting group, wherein at least one of the first resin and the second resin is particles.
Abstract:
A photopolymerizable composition that is cured with visible light or an infrared laser and is used as a recording layer in a negative planographic printing plate precursor. The photopolymerizable composition is cured by exposure and includes (A) a polymerizable compound that is solid at 25null C. and has at least one radical-polymerizable ethylenically unsaturated double bond in a molecule, (B) a radical polymerization initiator, (C) a binder polymer and, as required, (D) a compound generating heat by infrared exposure.
Abstract:
Disclosed are a printing plate precursor, a fabrication process of the printing plate precursor, a fabrication process of a printing plate, a regeneration process of the printing plate, a printing press, and a coating formulation for the printing plate precursor. According to the present invention, a printing plate can be fabricated directly from digital data, and sufficient image quality can be obtained without a developing step, i.e., a developer. To permit repeated use of the precursor, the precursor has a surface, which contains a photocatalyst and is capable of showing hydrophilicity when exposed to activating light having energy higher than band gap energy of the photocatalyst. A coating formulationnullwhich comprises fine particles of a thermoplastic resin having both a property that the particles unite to the surface when heated and a property that the particles decompose under action of the photocatalyst when exposed to activating light having energy higher than band gap energy of the photocatalystnullis applied as a hydrophobizing agent onto the surface. At least a part of the surface of the precursor is heated such that the fine particles applied on the part of the surface are fixed to form a hydrophobic image area. The fine particles applied on the remaining part of the surface with the image area formed thereon are then removed.
Abstract:
An image forming material having a support having disposed in an order thereon an acid-crosslinkable layer, which contains a compound that generates an acid by light or heat and a compound crosslinkable by the acid generated and whose alkali solubility is lowered by the crosslinking, and a radical-polymerizable layer, which contains a compound that generates a radical by light or heat and a compound capable of undergoing a radical polymerization and whose alkali solubility is lowered by the polymerization.
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.