METHOD AND APPARATUS FOR CORRECTING REGISTRATION FAULTS BASED ON CHANGES IN MACHINE STATE IN A MULTICOLOR PRINTING MACHINE

Apparatus and a method for correcting registration faults based on changes in machine state (4, 4′, . . . ; 5, 5′, . . . ) in a multicolor printing machine (1) having a number of printing units (13, 13′, . . . ) with image cylinders (14, 14′, . . . ) and exposure devices (2, 2′, . . . ) for the digital production of color separations (3, 3′, . . . ) on the image cylinders (14, 14′, . . . ), the actions of setting up and combining the color separations (3, 3′, . . . ) being controlled such that in-register prints are achieved. Changes in machine state (4, 4′, . . . ; 5, 5′, . . . ) are registered and, on the basis of these changes in machine state (4, 4′, . . . ; 5, 5′, . . . ), the production of the color separations (3, 3′, . . . ) is changed such that a disturbance to registration accuracy of the print, threatened by a change in machine state (4, 4′, . . . ; 5, 5′, . . . ), is compensated for.