PRINTING PLATE UNLOADING APPARATUS AND METHOD

摘要

A rotary web-offset printing press is disclosed. It includes a plate cylinder (2) defining a plurality of individual printing plate (8) positions thereon and apparatus for removing printing plates (8) from said individual printing plate positions or, for locating printing plates (8) in said individual printing plate positions. The apparatus includes a discrete vacuum circuit (5) associated with each individual printing plate position so that a negative pressure is generated within a vacuum circuit associated with an individual printing plate (8) position when that vacuum circuit is closed by the presence of a printing plate (8) in that individual printing plate position, wherein the plate cylinder (2) is configured so that closure of a vacuum circuit and generation of a negative pressure is prevented when no printing plate is present in an individual printing plate position on the plate cylinder, the press including means for detecting the generation of negative pressure in each vacuum circuit and for providing information relating to the outcome of that detection to an operator to enable the presence of a printing plate (8) in each individual printing plate position to be determined.