A rotary press is provided that prevents a print from contamination with a color different from a printing color. The rotary press comprising a printing unit (11) made of a set of printing cylinders such as plate and blanket cylinders or plate and impression cylinders for printing paper; and a dryer (14) disposed downstream of the printing unit for drying the paper printed, has a guide roller (19a,19b,19c) included therein for guiding the printed paper from the printing unit into the dryer wherein the guide roller has a diameter which is equal to, or a an integral multiple of, a diameter of a printing cylinder in the printing unit and is adapted to rotate synchronously with the printing cylinder and at a peripheral speed that is identical to that at which the printing cylinder is rotated.