Method and apparatus for registering a pre-printed web on a printing press

摘要

A preprinted web having a plurality of first repeating images is reprinted with a plurality of second repeating images which are in register with the first images. A register mark is printed on the web for each of the first images. When the web is reprinted, the positions of the register marks are sensed and compared with the positions of the second images, and the unwind tension of the web is adjusted to maintain the relative positions substantially constant.