Abstract: The machine substantially comprises two bays (9, 9a) accommodating the rotorgravure cylinders, either one of which is approachable from alongside by a trolley (4, 4a) carrying the print cylinder (6, 6a) and individually accessible regardless of whether the remaining bay is already occupied by a trolley and cylinder or not; each bay is served by its own impression cylinder (10, 10a) and doctor (8, 8a), which operate in conjunction with each replacement print cylinder brought in on the trolley. The speed with which print cylinders can be changed over and recommence operation is considerably enhanced by the design of the improved machine.

Abstract: The trolley comprises a movable frame (2) carrying two separate print assemblies comprising cylinder (5-5a), doctor (6-6a) and ink rail (7-7a), and is capable of traversing horizontally at right angles to the print station of a rotary machine; the frame can be locked into two distinct positions, each of which has one of the two print assemblies correctly aligned with the impression cylinder and the rotary drive shaft, while the other stands off the machine and is freely accessible for servicing purposes. The trolley also has its own on-board drive system capable of setting the cylinder of the spare print assembly in rotation on the frame, independently of the other cylinder, which continues occupying and operating in the print station, so that adjustments can be made in readiness for the next run without stopping the machine.