Abstract: The excess of damping liquid taken from the vessel 3 by the fountain roller 4 which rotates in the direction indicated by the arrow 6 is removed by the wiper element 9 formed of a body made of elastic material of circular cross section housed in a longitudinal groove in the rigid support bar 11. The fountain roller is rotated by the dc motor 5, the speed of which is adjusted by pulses coming from the processor 23 under the influence of the signal transmitted to the processor by the speed detector 23 which is located on the shaft of the plate roller 1. The speed can also be influenced by other signals transmitted to the processor, for instance from the keyboard 30 where it is possible to enter data relative to different characteristics of the equipment and of the damping liquid, for instance according to its viscosity. The fountain roller transfers the liquid to the duct roller 7, the peripheral speed of which is equal to that of the plate roller, or to the first of the rollers of the inking system.