Patent ID: 7035557

Claim:
Method for correction of the calibration of the register mark accurate and/or register accurate printing process of an electrophotographic printing unit, preferably of a color printing unit, comprising: identifying the influence of a toner field that is placed on a conveyor belt for print substrate sheets on the register mark, and/or registration of the printing process, and expressing such influence in the form of at least one correction value or parameter suitable for the correction of the calibration, at least one of the correction parameters for the influence of a certain print substrate is stored in a correction value table which is accessible for the registration of print substrate sheets for the printing process, and wherein, for identifying the influence of a toner field, and for determining at least one of the correction parameters for a calibration run, at least one such toner field is placed on the conveyor belt, and at least one register mark is placed on the conveyor belt in front of the toner field, and at least one register mark is placed on the conveyor belt behind the toner field, whereby each of said register mark markings is comprised of colors provided for the four-color printing process, and these register marks are recorded by measurement.