GB869382A - Moistening device for offset lithographic printing machines - Google Patents

Abstract

A moistening device for offset lithographic <PICT:0869382/III/1> printing machines has a deflector 21 comprising a flat plate 21a having notches of decreasing cross-section in the direction of rotation of a brush and mounted on an angularly adjustable spindle 21b. The deflector engages bristles 20 of the brush 13 to cause the bristles to project a spray on to a cylinder 2. The bristles may be wire, strip metal, synthetic material, e.g. nylon or rylsan, or of animal, vegetable or mineral origin. The brush 13 is rotated by a variable speed gear 19 (Fig. 2, not shown) through gears 18 provided at either end of a shaft 14, Fig. 1, thus permitting reversal of the shaft end for end. Moistening liquid is supplied to a stainless steel tank 1 by a reservoir 6 provided with a valve 8 and a filler plug 11. The tank 1 has an overflow pipe 4 and drain pipe 4 to maintain constant liquid level in the tank 1. The tank has a hood 22 provided with a slidably adjustable screen 23 for limiting the area of the cylinder 2 moistened by the spray. In a modification, bristles 20a (Fig. 3, not shown) engage notches 31 in an angularly adjustable plate 21, while cylindrical heads 37 are individually adjustable, by threaded rods 35, to mask off selected areas of the spray produced by the brush.