Abstract:
A method of deactivating and on-press developing an exposed lithographic printing plate is disclosed. The plate comprises on a substrate a photosensitive layer developable with ink and/or fountain solution and capable of hardening upon exposure to a radiation. The plate is exposed with the radiation, deactivated, and then on-press developed with ink and/or fountain solution. The deactivation of the exposed plate allows the handling of the plate under regular office light or any other light without causing the hardening of the non-exposed areas of the photosensitive layer.
Abstract:
To provide a lithographic printing plate precursor which is capable of undergoing image recording with infrared laser and exhibits high printing durability while maintaining stain resistance and preservation stability, and particularly, to provide a lithographic printing plate precursor capable of undergoing on-press development and a plate making method thereof, the invention is directed to a lithographic printing plate precursor comprising a hydrophilic support having thereon an image-recording layer containing (A) a polymer fine particle, (B) a radical polymerizable compound and (C) an infrared absorbing dye, wherein (A) the polymer fine particle is obtained by a reaction between a polyvalent isocyanate compound which is an adduct of a polyhydric phenol compound having two or more hydroxyl groups in its molecule and isophorone diisocyanate and a compound having an active hydrogen atom.
Abstract:
A thermal lithographic printing plate overcoat composition comprising (a) a water- soluble polymeric dye having an absorption band between about 300 and about 600 nm; and (b) micro-particles or nano-particles is provided. A negative-working thermal lithographic printing plate comprising (a) a hydrophilic substrate; (b) a near infrared imaging layer disposed on the hydrophilic substrate; and (c) an overcoat layer disposed on the imaging layer, said overcoat layer comprising a water-soluble polymeric dye having an absorption band between about 300 and about 600 nm; and micro-particles or nano-particles is also provided. Finally, a water-soluble polymeric dye having an absorption band between about 300 and about 600 nm is provided.
Abstract:
Imageable elements that can be imaged using infrared radiation comprise an imageable layer and a protective overcoat on a hydrophilic substrate. The imageable layer includes an IR-sensitive cyanine dye. The protective overcoat predominantly comprises one or more poly (vinyl alcohol) resins, each of which has a hydrolysis level of 85% or less. The use of this particular overcoat composition used in combination with the IR-sensitive cyanine dye provides improved tolerance to fogging by white light while maintaining desired imaging speed. The imageable elements are used for negative-working lithographic printing plates.