Abstract: Excellent development of planographic printing plates can be achieved by exposing an imaged, negative working, photopolymerizable coating to a high pressure stream of essentially heated but otherwise untreated tap water, whereby the water completely removes only the less cohesive and adhesive (e.g., partially polymerized) regions to the substrate, thereby directly producing a printing plate having an image pattern of highly cohesive and adhesive, oleophilic regions of the coating and hydrophilic regions of the substrate. The coating removal mechanism appears to be due entirely to ablation. The process variables of spray pressure, spray volumetric flow rate, and water temperature can be traded off to achieve one or more targets for plate quality, energy conservation, production rate, and equipment availability.

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: Excellent development of planographic printing plates can be achieved by exposing an imaged, negative working, photopolymerizable coating to a high pressure stream of essentially untreated tap water, whereby the water completely removes only the less cohesive and adhesive (e.g., partially polymerized) regions to the substrate, thereby directly producing a printing plate having an image pattern of highly cohesive and adhesive, oleophilic regions of the coating and hydrophilic regions of the substrate. The coating removal mechanism appears to be due entirely to ablation. The high pressure stream is preferably delivered to the plate through at least one nozzle having a discharge pressure greater than about 200 psi. Each nozzle preferably has a spray pattern that impinges the plate over a substantially rectangular region of the plate, and the nozzle and plate translate relative to each other.

Abstract: The invention generally relates to positive-working coating compositions and to a substrate formed with a coating of that composition. Advantageous versions of the invention provide an infrared imageable, positive lithographic printing plate having a coating comprising a hydroxy substituted polymer, a diphenylcarbinol solubility suppressing compound and an infrared radiation absorbing compound.

Abstract: Provided are 4-(alkoxyhydroxy)styryl triazine photoinitiator compounds having the formula: ##STR1## wherein n is 3 or 4, as well as photopolymerizable compositions and photographic elements containing such photoinitiator compounds. These photoinitiator compounds improve the reproduction quality of photographic elements such as lithographic printing plates since the photosensitive compositions in which they are incorporated are resistant to surface blooming.

Abstract: A light sensitive composition which is capable of photopolymerization which includes a photopolymerizable compound a free radical generating component and a benzanthrone or substituted benzanthrone which substantially prevents photopolymerization when the light sensitive composition is exposed to actinic radiation below a threshold amount but permits photopolymerization when the light sensitive composition is exposed to actinic radiation above a threshold amount. This achieves a gate effect which eliminates or decreases unwanted partial exposure in the nonimage areas and hence improves reproduction quality.

Abstract: Photopolymeric printing plates are presented wherein and electrochemically etched and anodized, silicated aluminum substrate has a single photosensitive coating thereon composed of a photopolymerizable combination which includes a photopolymerizable pigment dispersion, a photosensitive lithographic diazonium resin, multifunctional acrylate oligomer, multifunctional acrylate monomer, photopolymerizable binder and photoinitiator to yield a non-tacky, mar resistant, easily developed durable plate. In a preferred embodiment, an additional aqueous, non-photosensitive overcoat is applied over the initial coating to retard oxygen inhibition.

Abstract: Photopolymeric printing plates are presented wherein an electrochemically etched and anodized, silicated aluminum substrate has a single photosensitive coating thereon composed of a photopolymerizable combination which includes a photopolymerizable pigment dispersion, a photosensitive lithographic diazonium resin, multifunctional acrylate oligomer, multifunctional acrylate monomer, photopolymerizable binder and photoinitiator to yield a non-tacky, mar resistant, easily developed durable plate. In a preferred embodiment, an additional aqueous, non-photosensitive overcoat is applied over the initial coating to retard oxygen inhibition.