Abstract: A web fed offset printing press unit (42) including a frame (12), an auxiliary frame (44), a pair of plate cylinders (46 and 46a), a first blanket cylinder (48), a second blanket cylinder (50), a common impression cylinder (56) and an auxiliary impression cylinder (58) is disclosed. The second blanket cylinder is swung bodily through a short radius arc between a first end position in rolling contact with the common impression cylinder and a second end position in rolling contact with the auxiliary impression cylinder.In one arrangement, the second blanket cylinder is journaled in an eccentric sleeve (76) at each end and linkage (86) is switchable between the two modes of operation with a throw-off position associated with each.A method for converting a web fed letterpress unit (10) into a web fed offset printing press unit for multicolor or two-sided printing is disclosed.

Abstract: A vibrator mechanism for axially reciprocating the ink drums of a rotary printing press inking mechanism in predetermined phase relationship consists of coacting inner and outer eccentrics that are telescoped over each other and over a common drive shaft. The inner eccentric is releasably connected to the drive shaft so that it can be adjusted angularly about the drive shaft relative to the outer eccentric from a remote, conveniently accessible position to thereby vary the amplitude of the reciprocating motion imparted to the ink drums and the outer eccentric is connected to the drive shaft for positive rotation therewith by means which permit it to shift angularly and radially relative to the drive shaft to accommodate the angular adjustments of the inner eccentric.