Kodak Polychrome Graphics, Gmbh

Tore Harms

Shashikant Saraiya

Ken-ichi Shimazu

S Peter Pappas

Thi N Do

William P Keaveney

Xing-Fu Zhong

Presensitized lithographic plates are prepared which permit direct formation of printable images on plates by digital computerization without the intervening formation of a photographic image with a quality that allows the plates to be used for high volume printing applications. The lithographic printing plate has a structure which contains a substrate; a positive or negative working photosensitive layer; and a thermally sensitive masking layer which is opaque to the actinic radiation but which is soluble in an aqueous medium. The masking layer contains a heat softenable disperse phase which is insoluble in the aqueous medium; a polymeric continuous phase which is soluble or swellable in the aqueous medium; and a colorant which strongly absorbs radiant energy and converts the radiant energy to heat. In use the masking layer is digitally exposed to a computer controlled laser image so that exposed image areas of the masking are insolublized in the aqueous medium; soluble areas of the mask layer are then removed to form an opaque image mask on the photosensitive layer which is then exposed to actinic radiation passing through the mask to solubilize or insolubilize exposed areas of the photosensitive layer; the photosensitive layer is then developed with the developer liquid to remove the soluble areas and any overlying mask areas to form the lithographic printing plate. Both wet and waterless lithographic printing plates may be digitally prepared in this manner.

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Yorktown, NY, United States of America

Tore Harms