Abstract: A novel coating for lithographic printing plates can be imagewise exposed to radiation and then directly processed with only water to remove the non-exposed regions of the coating. The coating comprises a polymer, a monomer and/or oligomer, polymerization or cross link initiator, stabilizer, and dye or pigment, such that after imaging, the non-imaged resin areas are removable from the planar surface by penetration of water through the non-imaged coating without dissolution of the resin components of the coating, to form a lithographic printing plate with clearly defined image and non-image areas. The stabilizer is a solvent soluble, partially water soluble, non-polymerizable organic component that enables the coating to be removable by water in the non-cross linked areas.

Abstract: The invention provides a photosensitive element which comprises a sheet substrate having coated thereon an actinic radiation sensitive imageable layer. The imageable layer has an admixture an aromatic diazonium salt having an anion, and having a weight average molecular weight of from about 15,000 to about 35,000. The aromatic diazonium salt is present in an amount of from about 1 weight % to about 9 weight % of the imageable layer. The composition also has a solid epoxy polymer having a weight average molecular weight of from about 2,000 to about 8,000. The coating weight of the imageable layer per area is preferably from about 0.3 to about 0.9 g/m2. The imageable layer is sensitive to low levels of actinic irradiation, namely, from about 1 to about 40 mj/cm2 in the UV region. The sensitivity is increased by heating the imageable layer before development. After imagewise exposure and aqueous development, an imaged element is obtained, which is useful for lithographic printing.

Abstract: The invention provides a photosensitive element which comprises a sheet substrate having coated thereon an actinic radiation sensitive imageable layer. The imageable layer has an admixture an aromatic diazonium salt having an anion, and having a weight average molecular weight of from about 15,000 to about 35,000. The aromatic diazonium salt is present in an amount of from about 1 weight % to about 9 weight % of the imageable layer. The composition also has a cationic infrared absorbing dye which has the same anion as said aromatic diazonium salt, and a solid epoxy polymer having a weight average molecular weight of from about 2,000 to about 8,000. The coating weight of the imageable layer per area is preferably from about 0.3 to about 0.9 g/m2. The imageable layer is sensitive to low levels of actinic irradiation, namely, from about 1 and 40 mj/cm2 in the UV region and from about 50 to about 250 mj/cm2 in the IR region. The sensitivity is increased by heating the imageable layer before development.

Abstract: The invention relates to the application of a uniform film of a fluid to the surface of a flat workpiece as it is being conveyed through a workstation. The invention is specifically directed to the development of lithographic printing plates and comprises the application of the thin film of developer solution to each plate in a controlled manner using a wire-wound coating device and a unique manner of metering and feeding fresh fluid to the wire-wound device. Specifically, the fluid is gently fed onto the wire-wound device by simple volumetric displacement and overflow from the inside of a hollow tube onto the wire and the flow is controlled by sensing the beginning and end of each workpiece or plate. The hollow tube may be the wire-wound component or it may be a tube mounted above the wire-wound component. The developer is allowed to dwell on the plate as it is conveyed across a support structure for a sufficient time to allow for percolation into and/or dissolution of the soluble areas of the coating.