Method of image registration in a web fed, multiple printing rotary press

Abstract

For image registration as in a web fed, multiple color printing press, printing plates are employed each bearing a registration mark having a first line segment extending transversely of the web and a second line segment extending aslantly of the web. The registration marks are so located on the printing plates that their images reproduced on the web are in a row arranged longitudinally of the web and with spacings from one to another. The printed images of the registration marks on the traveling web are sensed optically in order to determine the actual distances between them and between the first and second line segments of each registration mark. The thus ascertained actual distances are converted into corresponding numbers of reference pulses, and these pulse numbers are compared with reference pulse numbers representative of the proper distances. The angular positions of the plate cylinders are adjusted in accordance with the differences between the pulse numbers representative of the actual distances between the registration mark images and the corresponding proper pulse numbers, whereas the lateral positions of the plate cylinders are adjusted in accordance with the difference between the pulse number representative of the actual distance between the first and second line segments of each mark and the corresponding proper pulse number.