At least one register and an ink density are controlled in a printing
machine having at least one printing unit which includes a forme
cylinder, a transfer cylinder, and a counter-pressure cylinder. An image
sensor records an image from a print substrate, which is imprinted with
ink, inside the printing unit, and sends data correlated to that image to
an evaluation unit. The data for the last printed image is compared with
prior data and in response, the evaluation unit generates a command that
is directed to an actuator for controlling the supply of ink. The image
sensor is oriented towards the print substrate and detects the entire
width of the printed substrate, which width is transverse to a direction
of substrate conveyance. The evaluation unit generates the actuating
command to control the supply of ink based on data from the image sensor
and taken over the entire width of the substrate. The evaluation unit
also controls register, based on this data. The forme cylinder has a
separate drive which can be controlled separately or that can be
regulated by the counter-pressure cylinder assigned to it.