Abstract: A plate clamping system and apparatus for holding a flexible printing plate in position on a rotary printing cylinder. The system includes a plate clamp assembly mounted in a gap in the wall of the rotary printing cylinder for holding the leading edge of the flexible printing plate and a tail clamp assembly mounted in the same longitudinal gap in the cylinder wall for gripping and applying tension to the flexible printing plate to hold it against the surface of the printing cylinder. The plate clamp includes a plurality of individual clamping mechanisms which are air pressure engaged and spring released to hold the leading edge of the flexible plate. The tail clamp assembly includes a plurality of tail clamp mechanisms which are spring applied and air pressure released. The tail clamp mechanisms have a two-stage operation wherein compression springs clamp the tail end of the printing plate and a second set of tension springs moves the mechanism to apply tension on the printing plate.

Abstract: A multi-color printing press having a single segmented impression cylinder with multiple, segmented blanket cylinders of equal diameter arranged about the periphery thereof. The segments of the impression cylinder and the blanket cylinders are equal in length and the number of segments on the impression cylinder is equal to the number of segments on the blanket cylinders multiplied by a whole number, plus one additional segment. Each blanket cylinder is provided with a plate cylinder of equal diameter which has the same number of segments. Color rolls provide each segment of the plate cylinder with a different color. Sheets to be printed are fed to the gripping means on the successive segments of the impression cylinder and delivery means removes sheets after printing. Each sheet is held on the impression cylinder for a number of revolutions equal to the number of segments on any one blanket cylinder.

Abstract: Apparatus and procedure for accurately positioning and magnetically holding a flexible ferrous plate on the surface of a rotary printing cylinder. Movable registering pins and a permanent bar magnet are mounted to the rotary cylinder and controlled by a single operating means. The pins and magnetic bar are alternately moved toward and away from the cylinder surface such that, when the pins are initially projected to register with positioning holes in the plate, the magnet is withdrawn. When the pins are withdrawn the magnet is simultaneously advanced to "grab" the leading edge of the plate. The operating means is controlled by a foot pedal linkage. The trailing edge of the plate is held in position by a second bar magnet. To remove the plate, the procedure is reversed so as to simultaneously advance the register pins and retract the bar magnet to release the leading edge of the plate.