Method of generating proofs of print signatures

摘要

The invention relates to a method of generating proofs of print signatures composed of first and second flats printed on opposite sides of a sheet. The method of the invention comprises the steps of (a) providing first and second digital printing units; (b) feeding a substrate having opposite sides to the first printing unit; (c) actuating the first printing unit while feeding thereto digital data representative of an image of the first flat so as to imprint one side of the substrate with the image of the first flat; (d) providing the substrate with a registration mark at a predetermined location on the substrate, before or during step (c); (e) conveying the imprinted substrate from the first printing unit to the second printing unit and feeding same thereto; (f) detecting the location of the registration mark on the substrate and actuating the second printing unit while feeding thereto digital data representative of an image of the second flat so as to imprint the other side of the substrate with the image of the second flat positioned with respect to the detected location of the registration mark such that the image of the second flat registers with the image of the first flat, thereby obtaining a proof of a print signature; and (g) discharging the proof of print signature from the second printing unit. Such a method enables one to avoid generating films from the digital data representative of both flats and preparing a proof from such films.