Producing predetermined patterns on photosensitive medium - applying computer-controlled laser beam and rotating drum to produce raster image

摘要

The data for production of colour separation masters are fed from a control unit (24) to a microprocessor (23) programmed as a Raster Image Processor - RIP. Signals from the processor switch a laser (22) on and off and cause it to move along a track (27) parallel to the axis (26) of a rotating drum (20). The laser beam produces a raster pattern on the cadmium sulphide photosensitive surface of the drum. When the latent image has been produced on the drum, it is toner developed and transferred to film or paper.