Abstract: A stack angle compensation arrangement is disclosed. This arrangement is for use with a skewing adjustment system in an offset printing press unit that is configured and disposed for receiving plate and blanket cylinders of various diameters. The arrangement keeps the rotation axis of the skewing adjustment system in line with a reference plane, which reference plane is defined by the rotation axis of a plate cylinder (before skewing) and the rotation axis of a blanket cylinder, when the stack angle changes. A method of automatically compensating a change in the stack angle in an offset printing press unit having a skewing adjustment system is also presented.

Abstract: In a printing press, an adjustment system for positioning a rolling element such as a form roller or an impression cylinder relative to a first cylinder having a first diameter and relative to at least a second cylinder adapted to replace the first cylinder and having a second diameter different than the first diameter, the system comprising an actuating member operable to displace the rolling element relative to the first cylinder and having a pivotable fixed first end and a second end mechanically linked to the rolling element, the actuating member providing sufficient displacement to bring the rolling element into contact with the first cylinder such that a predetermined contact pressure therebetween is reached, the actuating member also being operable to bring the rolling element into contact with the second cylinder such that the predetermined contact pressure therebetween is reached. A method for displacing a rolling element is also presented.

Abstract: A printing unit convertible between at least two printing modes comprising at least two interchangeable sets of cooperating printing cylinders. A first set of the cooperating printing cylinders includes a lithographic plate cylinder and a blanket cylinder and a second set of the cooperating printing cylinders includes an anilox cylinder and a flexographic plate cylinder. A selected one of the first and second sets is removably mounted in the printing unit with the cooperating printing cylinders thereof in rotatable contact with each other. The first set being selected to operate in an offset lithographic printing mode and the second set being selected to operate in a flexographic printing mode.

Abstract: An offset printing press having plate and blanket cylinder retention mechanisms, each retention mechanism having at least one trunnion axially displaceable between an operative position and a disengaged position. Said trunnion is freely disconnected from an associated 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. One of the cylinder retention mechanisms is selectively displaceable relative to the frame structure such that a distance between the cylinder axes of rotation is variable. The plate and blanket cylinders are thus removable from the printing press and substitutable with replacement cylinders having a different outer circumference. The press comprises a gear drive system which remains in gear meshed engagement with both the plate cylinder and the blanket cylinder regardless of the variable relative positions thereof.

Abstract: In a printing press, an adjustment system for positioning a rolling element such as a form roller or an impression cylinder relative to a first cylinder having a first diameter and relative to at least a second cylinder adapted to replace the first cylinder and having a second diameter different than the first diameter, the system comprising an actuating member operable to displace the rolling element relative to the first cylinder and having a pivotable fixed first end and a second end mechanically linked to the rolling element, the actuating member providing sufficient displacement to bring the rolling, element into contact with the first cylinder such that a predetermined contact pressure therebetween is reached, the actuating member also being operable to bring the rolling element into contact with the second cylinder such that the predetermined contact pressure therebetween is reached. A method for displacing a rolling element is also presented.

Abstract: An offset printing press having plate and blanket cylinder retention mechanisms, each retention mechanism having at least one trunnion axially displaceable between an operative position and a disengaged position. Said trunnion is freely disconnected from an associated 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. One of the cylinder retention mechanisms is selectively displaceable relative to the frame structure such that a distance between the cylinder axes of rotation is variable. The plate and blanket cylinders are thus removable from the printing press and substitutable with replacement cylinders having a different outer circumference. The press comprises a gear drive system which remains in gear meshed engagement with both the plate cylinder and the blanket cylinder regardless of the variable relative positions thereof.

Abstract: A perforation forming apparatus for a web fed paper processor generally comprising a perforator cylinder and an anvil cylinder. The rotatable perforator has at least a blade protruding radially from the cylinder. The rotatable anvil cylinder is adjacent the perforator cylinder and is contiguously engageable therewith. One of the perforator cylinder and the anvil cylinder is supported by eccentric bearing assemblies, comprising fluid cooled bearings eccentrically mounted in bearing housings and therefore adapted for rotation such that the eccentrically mounted cylinder can be pivotally displaced between a first and second position. Whereby pivoting to the second position during operation temporarily suspends perforation of the paper web, and returning to the first position during operation resumes perforation of the paper web.

Abstract: An offset printing press having a plate cylinder, a dampening unit and an inking unit. The dampening unit comprises a rotatable dampening form roller, a rotatable dampening fluid feed roller, and a rotatable auxiliary dampening roller. The rotatable dampening form roller is in removable contacting engagement with the plate cylinder along a contact stripe, and transfers dampening fluid to the plate cylinder. The rotatable dampening fluid feed roller is in removable contacting engagement with the dampening form roller and transfers dampening fluid thereto. The dampening fluid feed roller is in fluid flow communication with a dampening fluid source. The rotatable auxiliary dampening roller is in contacting engagement with the dampening form roller immediately upstream of the contact stripe.

Abstract: Interchangeable cassettes containing a blanket cylinder and a plate cylinder of varying circumferences can be located in a printing tower of an offset printing apparatus. An impression roller is journaled to a pair of sub-frame arms pivoted to the frame by means of a pivot shaft which extends through the gear side frame wall. The impression roller shaft extends through the gear side frame wall in an arcuate slot, and the impression gear meshes with the pivot shaft gear at all angles of displacement of the impression gear. A pivoting sub-frame includes exterior plates mounted to the pivot shaft and on the exterior of the frame walls. Hydraulic clamping devices can clamp the exterior sub-frame plates and the sub-frame arms to the frame wall.