Dampening device for lithographic printing press

A dampening mechanism for the plate cylinder of a rotary lithographic printing press comprising, a reservoir of dampening fluid, a supply roller having a smooth, continuous, resilient surface mounted for rotation about an axis parallel to the plate cylinder axis and with a portion of its surface immersed in said dampening fluid, a feed roller of rigid material mounted for rotation about an axis parallel to said supply roller and having its surface in pressure contact with said supply roller at a nip spaced from said reservoir, a plurality of circumferentially spaced, generally longitudinal grooves formed in the surface of said feed roller for sequentially advancing metered amounts of dampening fluid through said nip as the supply roller and the feed roller rotate, drive means for rotating said supply roller at a surface speed sufficient to convey a film of dampening fluid on its surface from said reservoir and to maintain a supply thereof at the said nip, and drive means for rotating said feed roller in an opposite direction with respect to and at a surface speed substantially greater than said supply roller whereby, upon passing through said nip, the longitudinal grooves sequentially advance metered amounts of dampening fluid through said nip and progressively spray said fluid toward the plate cylinder in the form of a substantially continuous, fine mist.