A printing unit of a printing machine is configured having at least two frame parts, a spacing between which can be modified. Several form cylinders and several transfer cylinders, which cooperate to print a web, are located on each of the at least two frame parts. The distance between the two frame parts is less when the printing unit is closed than it is when the printing unit is open. The printing unit includes at least two web guiding elements. A first tangent is established by a transfer cylinder of a stationary one of the frame parts. A second tangent is established by the at least two web guiding elements. The first tangent and the second tangent are spaced from each other at a distance.