Method of making newspaper printing plates

Abstract

A method of making printing plates for color newspaper printing almost free from causing color dislocation. The present invention includes an exposure step,of directly drawing a desired image on a plate material E from a plate feeding step,by laser beam according to image drawing signals from a computer, a development and fixing step,of treating the exposed surface to produce a printing plate,with the desired image, and a bending and boring step,of forming bent edge stoppers,at the two edges of the printing plate,for mounting the plate,on the plate cylinder,and at least one positioning hole,for positioning the plate,on the plate cylinder,. In the exposure step,, pilot marks P in a desired shape are drawn near the two edges of the plate material E at the same time that a desired image T is drawn on the image drawing area Q of the plate material E according to image drawing signals from the computer. The bending and boring step,involves providing standard marks S having the same shape and the same positional relation as the pilot marks P above the printing plate loading table,of the bending and boring unit, automatically checking the superimposition between the pilot marks P on the printing plate,placed on the printing plate loading table,and the standard marks S by detection signals from an image sensor camera,provided above each standard mark S so that when the superimposition dislocation between the standard marks P on the printing plate,and the standard marks S is found to be under a set value level, at least one positioning hole,as well as bent edge stoppers,are formed at the two edges of the printing plate