System for automatically removing dust from plate cylinders of printing

Abstract

A system for automatically removing dust from a plate cylinder of a printing press has a laminated structure for inputting a dust removal position, which comprises (a) a printed circuit substrate bearing thereon a reference signal input circuit of comb form with numerous comb conductors and position signal read-out circuits alternatively interposed respectively between adjacent pairs of comb conductors and (b) a pressure-activated conductor sheet superposed in laminated state on and over the circuit substrate. When a printed material having a printing defect due to dust on the printing plate is laid over with correct register on this laminated structure, and the part of the defect is pressed, the nearest conductors of the input circuit and of the read-out circuit are shorted to designate the position of the defect. The resulting signal is processed and is sent to a dust removing mechanism to move a disk-shaped elastic dust removing head to the corresponding dust existing part of the printing plate. The head is revolvable through small increments of angle to present new dust removing parts of its periphery for each dust removing action.