Abstract:
Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt% to about 8 wt% of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt% to about 15 wt% of an organic solvent or mixture of organic solvents.
Abstract:
A thermal lithographic printing plate, which can be imaged by thermal energy typically by imagewise exposure with an infrared emitting laser, a thermal printing head, etc., is made up of a hydrophilic substrate, and a composite layer structure composed of two layer coatings. Preferably, the first layer of the composite is composed of an aqueous developable polymer mixture containing a photothermal conversion material which is contiguous to the hydrophilic substrate. The second layer of the composite is composed of one or more non-aqueous soluble polymers which are soluble or dispersible in a solvent which does not dissolve the first layer. The plate is exposed with an infrared laser or a thermal print head, and upon aqueous development of the imaged plate, the exposed portions are removed exposing hydrophilic substrate surfaces receptive to conventional aqueous fountain solutions. The unexposed portions contain the ink-receptive image areas. Alternatively, the composite layer may be free of photothermal conversion material when thermal imaging is carried out using a thermal printing head.
Abstract:
Un elemento de formación térmica de imágenes que funciona como positivo, que comprende: (A) un sustrato y (B) una estructura laminar compuesta sensible térmicamente, que tiene una superficie interior contigua al sustrato y una superficie exterior, comprendiendo la estructura laminar compuesta: (a) una primera capa que tiene la superficie interior, comprendiendo la primera capa un primer material polimérico y un material de conversión fototérmica, siendo el primer material polimérico soluble o dispersable en una solución acuosa, y (b) una segunda capa que tiene la superficie exterior, comprendiendo la segunda capa un segundo material polimérico, siendo la segunda capa insoluble en la solución acuosa, en el que primero se aplica la primera capa, que contiene el material de conversión fototérmica, y posteriormente se aplica la segunda capa, en el que, tras calentar la estructura laminar compuesta, la estructura laminar compuesta queda provista de porciones calentadas y porciones complementarias no calentadas, y en el que las porciones calentadas tienen una velocidad incrementada de separación en la solución acuosa.
Abstract:
Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt % to about 8 wt % of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt % to about 15 wt % of an organic solvent or mixture of organic solvents.
Abstract:
Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt % to about 8 wt % of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt % to about 15 wt % of an organic solvent or mixture of organic solvents.