Producing a lithographic printing plate by sequentially exposing a thermo-sensitive imaging element by a set of radiation beams

摘要

A method for generating on a lithographic printing plate a screened reproduction of a contone image, comprising the steps of: (1) transporting a thermo-sensitive imaging element through an exposure area; (2) scanwise exposing the thermo-sensitive imaging element according to screened data representative for tones of a contone image with a set (s) of radiation beams (b) as the thermo-sensitive imaging element is transported through the exposure area, characterised in that at any given moment (ta + DELTA t) during the exposure at least two radiation beams (bi,bj) of the set of radiation beams impinge on different microdots (ma, ma + DELTA m) of a scanline (la) on the imaging element, so that by completion of the exposure step each effective microdot of the scanline has been impinged by all effective radiation beams of the set.