Abstract
We demonstrate a direct letterpress printing process which transpose the original letters to a photopolymer plate in the use of excimer laser beam. The photosensitized plastic resin plates are exposed to UV ray of 300-400nm. For the light source, the high pressure mercury vapour lamp which has a long exposure time was used. Xenon-fluorine excimer laser was used for the generation of very strong UV beam (350nm) to accept even low sensitive photopolymer plate. The critical hardening energy density was 40mJ/cm2 (10ns). The new method using this pulse beam for one letter is much simpler and easier than the laser scanning process requiring division of each letter into dots of 1 and 0.
