Abstract:
In a stack of lithographic printing plate precursors, each plate has an aluminum substrate, a photo-polymerizable (PS) layer carried on the upper surface of the substrate, a water soluble topcoat oxidation inhibitor carried on the PS layer, and a water insoluble bottom coat on the lower surface of the substrate, wherein the bottom coat of each intermediate plate is in direct covering contact with the topcoat of an immediately adjacent plate. The associated process includes cutting through multiple sections of the finished web without interleaving to produce stacks of finally sized precursor plates, and without interleafing, packaging together at least 25 stacked and confronting precursor plates.
Abstract:
A method for producing a lithographic plate from a negative working, radiation imageable plate having an oleophilic resin coating that reacts to radiation by cross linking and is non-ionically adhered to a hydrophilic substrate. The steps include imagewise radiation exposing the coating to produce an imaged plate having partially reacted image areas at an initial double bond conversion rate including unreacted coating material, and completely unreacted nonimage areas; developing the plate by removing only the unreacted, nonimage areas from the substrate while retaining unreacted material in the image areas; and subjecting the upper surface of the plate to blanket post treatment energy, which further reacts the retained unreacted material in the image areas to increase the initial double bond conversion rate, producing a lithographic printing plate with enhanced durability.