Windmoeller & Hoelscher Kg

Hermann-Josef Veismann

Frank Westhof

Uwe Hoewelmeyer

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 process for correcting the longitudinal registration error of a rotary printing press with several inking systems in which a control unit adjusts the desired application line of the printing plate on the material web lying on one of the two rollers. In making the adjustment, the control unit takes into account the shift of the effective print line that arises as a consequence of an adjustment movement of one of the two rollers along an axis that does not run coincident with the connecting line of the axes of rotation of the two rollers, and determines correction values from the relative positions of the two rollers and the inking system, and the angle between the connecting line of the axes of rotation and the axis of adjustment.

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Hoerstel, Germany

Hermann-Josef Veismann