Printing and photocopying device and method whereby one toner mark is scanned at at least two points of measurement

摘要

The invention relates to an electrographic printing or photocopying device and method. A toner mark (10) is provided on a photoconductive drum and printed with toner using a developing station. The toner mark (10) is scanned by a sensor at two points of measurement (a1,a2). The amount of toner in a developing mixture consisting of two components depends upon the difference (DELTAU) or the quotient of the amount of the signals of the sensor at both points of measurement. A device which is also disclosed enables the exact length of the toner mark (10) to be determined.