Method for eliminating gear train backlash in a drive for a multi- color sheet-fed printing machine having face printing and perfecting modes

摘要

A method for eliminating gear train backlash in the drive of a sheet- fed printing machines when changing the printing mode of the machine between face printing and perfecting or vice versa is disclosed. The printing machine has a gear train, a longitudinal drive shaft, and a plurality of input drives connecting the drive shaft to the gear train. At least one separation device is provided in the gear train, and at least one clutch is provided in the drive shaft. Releasing both the clutch and the separation device disconnects the printing machine into decoupled regions. After the relative position of those regions are adjusted for the new printing format, the new relative position is fixed by engaging the separation device. The segments of the longitudinal drive shaft is then adjusted to apply a torque to the gear train to eliminate backlash in the drive. The positioning can optionally be performed by the main drive motor or a separate positioning drive connected to the drive shaft.