Device for conveying ink or a damping agent

摘要

A fluid supply system for a lithographic printing press in which a fountain roller journalled in the frame of the press and driven at a slow speed is partially submerged so that a film of fluid is formed on its surface. A distributor roller is journalled in the frame parallel to the fountain roller and spaced therefrom to form a gap. A ductor roller movable broadwise in the gap is supported by a pair of arms which are, in turn, rigidly supported by a shaft journalled in the frame. A driving arm having a thrust rod connected thereto is rigidly secured to the shaft. The driving arm is coupled to a cam follower which engages a rotary cam so that upon rotation of the cam the shaft oscillates to swing the ductor roller back and forth for successive engagement of the fountain roller and the distributor roller to convey fluid therebetween. Opposed way surfaces are provided at the ends of the arms oriented generally perpendicular to the plane of the arms. Mounting blocks carrying the ends of the ductor roller are slidable on the way surfaces. Paired springs are provided on opposite sides of each of the mounting blocks in working opposition to one another so as to define a normal position of the ductor roller with respect to the arms. Upon engagement of the ductor roller with either the distributor roller or fountain roller, any relative overtravel of the cam follower is yieldingly accommodated by the deformation of the springs. A set screw in each arm prestresses the springs and adjusts the normal position of the ductor roller.