ELECTROPHOTOGRAPHIC METHOD FOR MANUFACTURING OFFSET PRINTING PLATES Russian patent published in 1999 - IPC

FIELD: polygraphy. SUBSTANCE: light-sensitive layer is applied onto conducting backing from organic solution, layer beings composed of 33.2-77.7 wt % of organic photoconductor - N,N-diphenyl-alpha- naphtylamine, or N,N-diphenyl-beta-naphtylamine, or N-phenyl-N-tolyl- beta-naphtylamine, or N-phenyl-N-(p-ethylphenyl)-beta-naphtylamine; 0.5-9.1 wt % of sensitizer - 2,4-diarylpyrilium salt, or triarylmethane dye, or oxazine dye; and binding agent - polyvinylbutyral, or polyvinylethylal, or poly-N-vinylpyrrolidol, or vinylacetate/N-vinylpyrrolidone copolymer (the balance). Coated backing is dried, charged by means of corona discharge, exposed to visible light, and developed by electrophotographic ink powder, after which resulting image is thermally fixed, light-sensitive layer is removed from spaces with solution containing 80-90 wt % of ethyl or isopropyl alcohol and glycerol and then submitted to hydrophilization. EFFECT: improved quality of offset plates due to increased bend strength of light-sensitive layer. 1 tbl