Apparatus for decorating beverage cans using a flexographic process

Abstract

A decorator for cylindrical objects, such as beverage cans and the like. The cylindrical members are carried by mandrels which are sequentially presented to rotating printing plates. A plurality of mandrels are carried by a mandrel cluster and the printing plates are carried by plate wheels. The decorator is capable of utilizing flexographic inks wherein the surface of the cylindrical body can be printed with a first ink, the ink rapidly dried, followed by the application of the second ink. The mandrels are compliantly supported on the mandrel cluster by pneumatic cylinders supplied with both high and low pressure air so that the spring rate of the complaint support may be varied to ensure uniform printing. Synchronization of the rotation of a mandrel with the rotation of a printing plate carried by a plate cylinder is critical so that the second image is precisely in register with respect to a first applied image. A particular feature is the utilization of synchronized electric motors to rotate the various parts of the decorator with each electric motor having an encoder and wherein an electronic controller controls the rotational position of each motor so as to effect the synchronization of the several motors and the precise registration of the components.