Man Roland Druckmaschinen Ag

Man Roland Druckmaschinen

Winfried Hartung

Valentin Gensheimer

Gerd Steiner

In a printing machine having means for adjusting the circumferential, axial and diagonal register of a plurality of plate cylinders on which printing plates are secured, wherein each plate cylinder is mounted on a shaft for rotation and each printing plate has register markers disposed thereon outside of its respective printing and inking zone, the improvement comprising: a register marker detection system comprising at least one illuminating means disposed on one side of each plate for generating and projecting light to illuminate said register markers; at least one photo-detecting means disposed on the other side of each plate for periodically detecting said light projecting through the register markers as the cylinder rotates the printing plate and for generating measurement signals in response thereto; and circuit means connected to said photo-detecting means for generating signals to control said cylinder register adjustment means; said register markers comprising at least first and second accurate-register apertures; and said illuminating means and said photo-detecting means being positioned such that the light generated by said illuminating means is detected by said photo-detecting means after passing through said apertures.

Arrangement in printing machines with adjustment means for

A resilient sheet gripper for a sheet-fed rotary printing press having a clamping member secured to a gripper shaft and a pivoting gripper finger resiliently connected to the clamping member by an adjustable compression spring is provided, including eccentric bushings mounted on the gripper shaft, the gripper finger being journaled thereon, so as to impart a positive gripper closing movement substantially perpendicular to a gripper support.

Resilient sheet gripper for a sheet-fed rotary printing press

A resilient sheet gripper for a sheet-fed rotary printing press having a gripper shaft and a gripper finger disposed in a recess of a cylinder of the printing press and including an asymmetrical four-pivot mechanism having the gripper finger as one of its links for governing the motion of the gripper finger and ensuring perpendicular closing of the tip thereof with respect to a sheet engaged on a gripper support at the edge of the recess.

A device for measuring pressure between two cylinders of a press includes a plate mounted to the end of a journal of one of the cylinders in a position perpendicular to the cylinder axis, and a set of electrical proximity sensors measuring the tilting of the plate as a result of slight bowing of the cylinder in response to changes in applied pressure. The proximity sensors are disposed at diametric locations at a substantial radius with respect to the cylinder axis, and an electrical circuit combines signals from the proximity sensors in such a way as to cancel signals generated in response to axial shifting of the cylinder to which the plate is mounted. Preferably the sensors are mounted in the common plane including the two cylinders and a set of sensors is disposed on each side of the plate. Additional sensors can be used to independently measure the pressure applied by a third cylinder engaging the cylinder to which the plate is mounted.

System for measuring the engagement pressure between cylinders of a

A force or movement sensor is disposed on or proximate to an impression cylinder of a sheet-fed printing machine in order to sense the printing pressure. The sensor is sampled in synchronism with the rotation of the impression cylinder and the feeding of the sheets in order to detect a first pressure signal when pressure is applied to the fed sheets, and to detect a second pressure signal when the impression cylinder is relieved of the printing pressure. The differential value of the first and second pressure signals is displayed as an output or is evaluated by a pressure control system. As a result, static and quasi-static disturbances are suppressed. The mesurement is not affected by wear of the cylinder bearings or journals, variations in machine speed, and zero-point shift in the sensor and its associated electronics. These disturbances are further suppressed by averaging or accumulating samples over sample intervals and over a number of revolutions of the impression cylinder. Also, by proper synchronization of the sampling intervals with the feeding of sheets to the impression cylinder, the method can be used in a two-color rotary press for separately determining and independently controlling the pressures from the top and bottom ink transfer cylinders in response to a single sensor at the impression cylinder.

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Offenbach am Main, Germany

Winfried Hartung