Method and apparatus for determining of register errors are printed on a multicolored printed with register marks running

摘要

One or more photoelectric receivers with essentially uniform spectral sensitivity detect the light emanating from the marks on a recording material which is moved w.r.t. the receivers. The receiver signals are amplified and evaluated to determine positional deviations of the marks from their desired positions. An incremental position measurement arrangement for the actual mark positions w.r.t. a reference position can be connected to the evaluation device. The inputs of a comparator in the evaluation device are connected to the amplifier output and to a reference voltage source. The position measurement arrangement feeds the count input of a counter with set and reset inputs controlled centrally. The counter output drives a gain controller followed by a correction unit controlled by the comparator. The correction unit drives the amplifier's control input and a gain controller set input. ADVANTAGE - Accurate detection of rapidly moving recording marks at low cost.