MASTER LOADING AND UNLOADING APPARATUS FOR A LITHOGRAPHIC PRINTING MACHINE

摘要

An apparatus is disclosed for loading a master onto and unloading the master from the rotating master cylinder in a lithographic printing machine at substantially the same angular position of cylinder rotation. The apparatus includes external grippers for gripping a master edge and moving it into the proximity of the cylinder through a master delivery path. Internal grippers for gripping and later releasing the master edge in the proximity of the cylinder are mounted in the cylinder and are extendable beyond the cylinder surface during a first angular sector of cylinder rotation to describe a master receiving path that intersects the master delivery path in a loading merger region. The internal grippers are also extendable beyond the cylinder surface in a second angular sector of cylinder rotation to describe a master release path. A stripper chute for unloading the master from the cylinder is movable into the proximity of the cylinder to describe a master stripping path that intersects the master release path in an unloading merger region. These three master handling components are operated in coordinated fashion by related mechanisms which include a transfer actuator that operates the external grippers to grip a master edge and deliver it to and release it in the loading merger region. A load control mechanism selectively operates the internal grippers to traverse the master receiving path, grip the delivered master edge, and later traverse the master release path and release the master edge in the unloading merger region.