Plate cylinder, external plate register tool, and method of registering plates

1. Field of the Invention A plate cylinder comprising a cylinder body having at least one external slot extending axially with respect to the cylinder body, and at least one register pin slidable by an external registration device within the slot. Also provided is an external registration device comprising a base for attaching to a periphery of a plate cylinder, and a pin pusher interacting with a register pin in a slot of the plate cylinder, the pin pusher being axially movable relative to the base. A method is provided for registering plates on a plate cylinder comprising the steps of placing an external registration device on a plate cylinder having at least one register pin, and moving the register pin axially with the external registration device.