Production of printing forms for multi-color printing, involves scanning a rotating blank with laser beams from several moving arrays, using a special control system to prevent overlaps and gaps in the pattern

摘要

A method for the production of printing forms for multi-color printing by scanning a rotating blank with radiation from modules carrying arrays of individual radiation sources, in which the differences between actual and control spacings between helical imaging tracks are stored and used as control data to prevent imaging overlaps or gaps. A method for the production of a printing form for multi-color printing, in which a blank is rotated in a principal scanning direction (PSD), at least two modules of similar linear arrays of individual radiation sources are moved in a synchronous manner in a scanning direction (SSD) at right angles to the PSD, and the radiation sources are controlled with the data from a partial image of the printing format so that ink-absorbing image spots are formed by the action of heat from the radiation in many helical imaging tracks with a spacing in the SSD which is many times greater than the distance between two immediately adjacent image spots. The method involves determining and storing the differences between actual and control spacings for the imaging tracks (30, 36) of equivalent radiation sources (20, 34) in different modules (16-19; 32, 33), transferring data packets of similar size one after the other from the data for the partial image to all modules via a data line and masking off the data packets from one module at the edges of the image depending on the above differences; imaging with radiation sources (20, 34) located at the edge is suppressed with the masked-out data.