The advantage of a conventional system is the simple mechanics. The disadvantage is that every time the rubber roll is moved, the web tension and register changes. This means the web must be slowed, and the color to color register will be affected. This creates waste and lowers productivity every time the roll is moved. The impression roll is moved using either a hydraulic or pneumatic pressure system.
Pneumatic systems are the most common.
There are two ways to set the impression pressure. The first is the stop or gap method. This method uses two steel blocks to limit the contact of the impression roll against the cylinder. This method does not allow an actual impression pressure measurement. The blocks stop the roller at a certain distance.