PRESSPLATE POSITIONING DEVICE IN MULTI-COLOR LITHOGRAPHIC PROOF PRESS

摘要

PURPOSE:To rapidly read how to conduct the positional correction of a second- color pressplate to a first-color pressplate by a construction wherein a mark- detecting optical system is composed of electronic-imaging optical systems, an indicating means is mounted on a frame of a register mark detector, and register marks picked up by the two or more electronic-imaging optical systems are simultaneously indicated by the indicating means. CONSTITUTION:A plurality of register marks 55 recorded on the surface of a plate are respectively picked up by electronic-imaging optical systems 45. A register mark detector 40 is set above a first-color plate platen 11, and the positions of the plurality of register marks 55 on the surface of the plate are read on the image planes of an indicating means 46 using bench marks 56 or the like. Thereafter, the detector 40 is set above a second-color plate platen 12, and in a similar manner register marks 55 on the surface of a second-color plate are simultaneously projected on the image planes of the indicating means 46. An operator can visually recognize the positional deviation of the second- color resistor marks 55 at the same time by the image planes, therefore rapidly reading how the whole second-color pressplate should be positionally corrected.