Copying by exposing material to change adhesiveness and applying toner - which becomes more adhesive on exposure, esp. for making multicolour negative proof with overlapping colour areas

摘要

Copying process involves (a) coating a support with a radiation-sensitive layer (I), the adhesiveness of which can be changed by exposure to actinic radiation; (b) changing the adhesiveness of certain areas by selective exposure; (c) applying a toner (II), which adheres to the adhesive areas; and (d) removing excess (II) from the other areas. The novelty is that the adhesiveness of the (II) used can be increased by exposure to actinic radiation. For multicolour copies, stages () to (d) are repeated at least once. (II) contains a radiation-sensitive material (III) and colorant(s) (IV), comprising finely-divided pigment(s) and/or finely-divided powder(s) with dissolved dyestuff(s). (I) contains and (III) is a light-sensitive dihydropyridine cpd. or light-sensitive system contg. a hexaarylbisimidazole cpd. and a dihydropyridine cpd. or a thioamide or thiolactam. USE/ADVANTAGE - The process is useful for making colour proofs, esp. multicolour negative colour proofs with overlapping coloured areas, since it does not entail transfer of exposed areas or other intermediate stages. It is also suitable for making multicolour positive colour proof