Patent ID: 7011022

Claim:
An offset printing press comprising: a plate cylinder, a blanket cylinder and an impression cylinder each mounted in a frame structure for rotation about parallel individual axes of rotation, the plate cylinder and the blanket cylinder having a common outer circumference defining a print repeat size produced by the plate and blanket cylinders; plate and blanket cylinder retention mechanisms respectively engaging the plate cylinder and the blanket cylinder, each retention mechanism comprising first and second trunnions rotatable within the frame structure and respectively engageable to a corresponding cylinder end, at least one of said first and second trunnions being axially displaceable by an actuating member between an operative position and a disengaged position, said at least one trunnion being fastenable in mating engagement with said corresponding cylinder end in the operative position and freely disconnected from said corresponding cylinder end in the disengaged position, such that the plate cylinder and the blanket cylinder are removable from the printing press from between the frame structure; and wherein at least one of the plate and blanket cylinder retention mechanisms is selectively displaceable relative to the frame structure such that a distance between the axes of rotation is variable, said at least one cylinder retention mechanism being fastenable in a desired position to maintain the distance at a predetermined value; whereby the plate and blanket cylinders are removable from the printing press and substitutable with replacement cylinders having a different outer circumference, thereby providing a correspondingly different sized print repeat when the replacement cylinders are installed into the printing press.