Lithographic printing plate prodn. - by silver complex diffusion transfer in presence of N-heterocyclic mercaptan and organic thioether for high ink affinity

摘要

Lithographic printing plate prodn. from light-sensitive material with Ag halide (AgX) emulsion coat(s) and a physical development nuclei coat on a base by a Ag complex diffusion transfer process involves diffusion transfer processing in the presence of N-heterocyclic mercaptan(s) (I) and (cyclo)aliphatic thioether(s) (II) of the formulae. In the formulae, Z = a gp. completing a 5-6 membered ring with N and c atoms; R = H, alkyl, aryl or aralkyl, each R1 and R2 = alkyl or together = a ring; R3 = alkylene, opt. with a divalent radical in the chain, and may vary if m = 2 or more; m = 0-4. ADVANTAGE - Combined use of (I) and (II) gives the printing plates much higher ink affinity than usual and greatly reduces plate wear. Pref. (I) and (II) are used in the diffusion transfer processing soln.