Flexographic printing system

Claim 1

A flexographic printing assembly for supplying ink to a print cylinder comprising: A. a frame held in fixed position with respect to the print cylinder; B. a pair of spaced pivot arms, said pivot arms being pivotally mounted on opposing sides of said frame for pivotal movement about a first axis; C. an engraved transfer roll having each end rotatably mounted on the lower end of one of said pivot arms, the axis of said transfer roll being movable in an arcuate path with respect to the print cylinder due to the pivotal mounting of said pivot arms with the center of gravity of said transfer roll exerting a passive moment arm tending to move said transfer roll towards the print cylinder; D. a pair of spaced wipe arms pivotally mounted on said frame for movement about a second axis parallel to said first axis; E. a wipe roll having each end rotatably mounted on the lower end of one of said wipe arms, the center of gravity of said wipe roll exerting a first moment arm that moves said wipe roll into contact with said transfer roll with said first moment arm capable of overcoming said passive moment arm when said wipe roll and said transfer roll are in contact to thereby move said transfer roll out of contact with said print cylinder; F. a pair of adjustable spring-loaded tie bars, each of said tie bars connecting the upper end of one of said wipe arms and the upper end of one of said pivot arms for exerting on each of said one wipe arm and said one pivot arm a force creating a moment arm that opposes the gravity-induced moment arm applied to the respective wipe arm and pivot arm; G. stop means mounted on said frame for engaging said pivot arms to limit the pivotal movement of said pivot arms and thus limit the approach of said transfer roll towards said print cylinder; H. releasable actuating means for exerting a releasable second moment arm on said pivot arms that can overcome said first moment arm and thus rotate said pivot arms into engagement with said stop means to hold said transfer roll in fixed ink transfer relationship with the print cylinder during printing operations, with the release of said actuating means permitting said first moment arm to move said transfer roll out of contact with the print cylinder; and I. supply means for feeding ink to the nip formed by the wipe roll and the engraved transfer roll.