METHOD FOR CALIBRATING A PRINTING MACHINE

摘要

This application relates to a method for calibrating a printing machine, in particular a digital multi-color printing machine adapted for duplex printing comprising a plurality of printing units. The method comprises the steps of transporting a first group of sheets of an at least semi-transparent type through the printing machine in such a manner that the sheets are moved at least once through the plurality of printing units, transporting a second group of sheets of an at least semi-transparent type through the printing machine in such a manner that the sheets are moved at least twice through the plurality of printing units, with the sheets being turned over between the passages, printing at least one register mark on one of the sheets of the first group of sheets during the first passage through the printing units, measuring the respective register mark at a register sensor located -in the transport direction of the sheets - downstream of the plurality of printing units, printing at least one register mark on one of the sheets of the second group of sheets during the second passage through the printing units, with no register marks being printed during the first passage, measuring the respective register mark at the register sensor located - in the transport direction of the sheets - downstream of the plurality of printing units, and detecting calibration parameters with the use of the thusly obtained measured results provided by the register sensor.