Windmoeller & Hoelscher Kg

Uwe Hoewelmeyer

Frank Westhof

Rainer Ehrenberg

Frank Gunschera

Manfred Loddenkoetter

Martin Kruempelmann

Mario Frankenberg

Hermann-Josef Veismann

A method of adjusting the print repeat length of a print image in a multicolor rotary printing machine, particularly a flexographic printing press, having a central impression cylinder, a first plate cylinder, and a second plate cylinder, including modifying the peripheral velocity of the first plate cylinder and the peripheral velocity of the second plate cylinder during printing operation, relative to the peripheral velocity of the central impression cylinder, and adjusting the longitudinal register of the first plate cylinder having the modified peripheral velocity and the longitudinal register of the second plate cylinder having the modified peripheral velocity.

Method for adjusting the print repeat length of a print image in a multicolor rotary printing machine

A method and an apparatus for operating a printing press determine the vibration behavior of at least one impression cylinder of the printing press, with the avoidance or suppression of undesirable vibrations such as resonant vibrations by utilizing measures in the range of the critical frequencies which trigger the vibrations. During operation of a printing press of this type, undesirable vibrations occur which cause quality impairments in relation to the printed image. The invention reduces quality impairments of this type. The problem is solved by performing targeted loading of the drive of the impression cylinder of the printing press with an exciting signal of the power output to cause vibrations of the impression cylinder, and determining critical frequencies in the resonant frequency spectrum of the impression cylinder using the vibrations which are caused.

Printing machine and method of operating the machine to avoid undesired vibrations

A printing machine with at least one inking unit which has at least two cylinders which are set against each other during the printing operation and can be rotated by at least one drive. The printing machine is provided with sensors for recording parameters of the rotary motion of the cylinders such as the torque and speed. A setting mechanism is provided for setting the at least two cylinders against each other in radial direction. The control unit is configured to trigger the setting mechanism to set the at least two cylinders against each other. The at least two cylinders are brought to different circumferential velocities and set against each other. The relative position of the two cylinders is recorded or maintained when at least one parameter of the rotary motion of the at least two cylinders exceeds a threshold value.

Device and method for setting at least two cylinders of a printing machine against each other

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Ibbenbueren, Germany

Uwe Hoewelmeyer