PROCEDURES AND ARRANGEMENTS FOR DETECTING REGISTRATION ERRORS ON A PRINTED PRODUCT PROVIDED WITH REGISTER MARKS

摘要

In a procedure for determining registration errors on a printed product provided with register marks, in which the register marks undergo opto-electrical scanning when the printed product passes through the printing machine, and in which the register marks undergo two scannings along the web whereby the scannings are separated by a predetermined time interval. A further signal is produced by subtraction of the signals obtained through the scanning operation. The timedependent position of the extreme value of the additional signal makes it possible to measure the position of the register mark.