Drum surface scanner and method for plate size check

Abstract

Provided is a drum surface scanner with which punched holes and/or cuts can be formed in a plate which has been correctly defined by position, and the plate can be clamped to a recording drum. When a plate P comes in front of movable pinsi.e., on a hole punch unitside, the upper roller of a conveyor rollermoves down, and conveyor rollersandand conveyor beltsall start rotating in the positive direction. Once the plate P moves out of the range covered by a sensor PHthe movable pinsfollow the tail end of the plate P at a given distance therefrom. When the front end of the plate P reaches the hole punch unitthe movable pinswhich have been chasing the plate P push the tail end thereof to make the front end thereof abut to the hole punch unitAt the same time, based on the movement amount of the movable pinsfrom their original positions to current positions pushing the tail end of the plate P, the plate P is checked for its length Y. Plate conveyance with respect to positioning pinson the recording drumis carried out in a similar manner.