GB1301794A - - Google Patents

Abstract

1301794 Doctoring apparatus for coating roller PAPER CONVERTING MACHINE CO Inc 17 Sept 1971 [24 May 1971] 43512/71 Heading D1L Apparatus for coating a web W backed by an impression cylinder 13 comprises a roll 11 on a shaft 11a journalled for rotation on a frame (10) (Fig. 2, not shown); a casing 17 mounted on the frame adjacent to the roll 11; means 16 for delivering coating liquid to the casing; and a housing 14 about said roll 11 and casing 17; the casing having side, end and bottom walls with the end walls (20) (Fig. 2), spaced from the ends of the roll 11 to define a narrow gap (27) therebetween and the bottom wall 19 having a generally planar elongated reverse-angled doctor blade 25 arranged to contact the coating roll 11 and define with the roll, end walls (20) and side wall 18 a chamber for the coating liquid. The casing 17 is movable towards and away from the roll 11, to alter the pressure of the doctor blade 25 against the coating roll, by means of a hand wheel 29 on shaft 30 equipped with a worm 31 engaged with wormgear 32 and thus threaded rod 33 (see also, Fig. 2). The casing 17 may be provided with a baffle plate 23 to reduce foaming at the coating -liquid in the reservoir 24 of the-casing. In operation coating liquid is supplied to casing 17, and spread to the desired thickness on coating roll 11 rotating in the direction of arrow 26 by doctor blade 25, excess liquid escaping through the gap (27) between end walls (20) and the end faces (21) of the roll to drop onto screen 14a in the housing 14 and then to be recirculated to the liquid supply means. Excess liquid which adheres to the end faces of the roll may be wiped from the roll by wiper 22.