DRY TYPE PRINTING PLATE HAVING BOTH PHOTOSENSITIVE POLYMER AND DIAZO LAYERS

摘要

This invention relates to energy sensitized sheet constructions, which upon exposure to an ultraviolet energy source through a screened image can accurately and simultaneously reproduce said image in both its negative and positive forms. One form of said reproduction comprises a lithographic printing plate. The sheet construction in one embodiment comprises (1) a transparent top sheet; (2) a photo-polymerisable layer; (3) a light sensitive diazonium layer in contact with the surface of the photo-polymerisable layer; and (4) a base sheet layer supporting the diazonium layer. After exposure the layers may be separated to provide negative and positive images.