Abstract: The present invention provides a method of preparing a lithographic printing plate, said method comprising:

Abstract: The present invention provides a method of preparing a lithographic printing plate, said method comprising: providing a lithographic printing plate precursor comprising: i) a grained and anodized aluminum substrate where the anodic weight is between 6.0 and 20 g/m2, having coated thereon; ii) a metallic layer; and image-wise exposing the precursor on an external drum thermal imaging device. The method provides press ready plates showing high image quality, good press properties and high durability on press without the requirement for the use of costly intermediate film and developer chemistry, and the attendant inconvenience resulting from the use of these materials.

Abstract: A lithographic printing plate precursor comprises a grained and anodized aluminum substrate coated with a metallic layer, preferably a silver layer, on top of which is applied a layer comprising at least one oleophilising agent and at least one hydrophilic stain-reducing agent, the hydrophilic agent being chosen such that it adsorbs onto the metallic layer but is not so strongly adsorbed thereon as to displace the oleophilising agent. Preferably, the oleophilising agent comprises a mercaptotetrazole or mercaptooxadiazole derivative, the hydrophilic stain-reducing agent comprises a material which includes at least one sulfur, selenium or tellurium containing group, and the layer additionally comprises an additional hydrophilic material.

Abstract: An apparatus is provided for processing a lithographic printing plate precursor comprising an aluminium support, an image-receiving layer and a silver halide emulsion layer. The apparatus comprises a tank for holding a processing liquid, at least one set of driving rollers, at least one guide roller or guide plate and means for providing direct electrical contact between the lithographic printing plate precursor and other electrically conducting surfaces in the apparatus which are in contact with the processing liquid. A method of processing a lithographic printing plate precursor using the apparatus is also disclosed. Undesirable electrochemical cell formation during processing, and the consequent deleterious effects on silver image formation, are prevented and subsequent problems with poor plate run length can therefore be avoided.

Abstract: The invention provides a lithographic printing plate precursor comprising a grained and anodized aluminium substrate having coated thereon a silver halide emulsion layer, the back surface of said substrate being coated with an inert coating which does not chemically or physically interact with an adjacent silver halide layer when two plates are placed in front to back contact. Fogging of the silver halide layer is avoided and the use of the back coating eliminates the requirement for the use of tissue interleaving when wrapping and packing the lithographic printing plate precursors.

Abstract: A wash liquor for use in the decoating of a silver halide diffusion transfer printing plate comprises an aqueous solution containing at least one organic or inorganic acid salt, such as the silicate, metasilicate, tartrate, citrate, hydroxycarboxylate, borate, hexametaphosphate, tripolyphosphate or pyrophosphate of sodium or potassium. The liquor preferably also contains at least one of a non-ionic surfactant, an enzyme and a biocide. A process for the decoating of the said printing plate is also disclosed.

Abstract: A wash liquor for use in the decoating of a silver halide diffusion transfer printing plate comprises an aqueous solution containing at least one non-ionic surfactant, such as an alcohol ethoxylate, an alkylphenol ethoxylate or an alkylamine ethoxylate. The liquor preferably also contains at least one organic or inorganic acid salt, and at least one of an enzyme, a biocide and an anti-foam. A process for the decoating of the said printing plate is also disclosed.

Abstract: Laminates of aluminum and plastic form the substrate of printing plate precursors that are suitable for imaging in conventional roll-fed imagesetters or phototypesetters.