Doctor blade head assembly and printing apparatus therewith

Abstract

A doctor blade head assembly, particularly for use in a flexographic printing press, has a head body pivoted to a support frame with an inflatable air tube disposed therebetween. The air tube extends along a channel having a bottom formed with spaced apart raised portions which cause the air tube to bulge out at these locations. In this way the air tube essentially only presses against the head body at these spaced apart locations, for example at the center and adjacent the ends, which reduces the tendency of the head body to bend along its length. This provides a more uniform ink film on the ink roll being inked by the doctor blade head assembly. End seal arrangements at the ends of the head body each include a resilient block seal and a resilient pad seal with which greased edge portions of the doctor blades slidably engage. The doctor blades overhang the ends of the ink roll, and an ink outlet passageway extends through each end seal arrangement independently of the seals.