GB397164A - Improvements in and relating to printing cylinders - Google Patents

Abstract

397,164. Printing-machines. HAWARD, E. W., Cambridge House, Richmond Bridge, East Twickenham, Middlesex, and HOPKINS, A. T., 59, Mayfield Avenue, Orpington, Kent. Jan. 19, 1932, No. 1672. [Class 100 (ii).] Printing - surfaces ; inking - apparatus.- In a printing or plate cylinder for intaglio printing - machines having a gap plate, the longitudinal edges of the gap plate and of the gap in the cylinder are so formed at each line of junction relativelv one to the other that the surface to the rear of each line of junction, considered in the direction of rotation of the cylinder, is elevated above the surface forward of the line, for the formation of a longitudinal ridge adapted to bear against the underside of the doctor blade, to lift the edge of the blade out of contact with the surface as it passes over the lines of junction. At the first line of junction between the cylinder a and gap plate b, the gap plate may be formed with a ridge c, extending longitudinally along the edge of the plate. The surface of the plate thence slopes downwardly slightly below the normal surfaces of the cylinder and finally, towards the ends of the gap, curves upwardly to join the cylinder edge, which forms thereby a ridge d. The ridges c, d serve to elevate the blade e out of contact with the cylinder at the lines of junction. In a modification, a ridge may be formed at the first line of junction by providing the surface of the cylinder adjacent the gap edge depressed slightly to form a shallow recess, which at the second line of junction the ridge may be formed by slight longitudinal elevation of the cylinder surface at the edge of the gap. The edges of the ridges are rounded or otherwise formed to avoid sudden inflection of the doctor blade.