Patent GB-608285-A (GB)
Title: Material separating and delivery means
IPC: G03B27/30
Filed: 1946-03-04
Abstract: 608,285. Sheetdelivery apparatus. GENERAL ANILINE & FILM CORPORATION. March 4, 1946, No. 6712. Convention date, March 6, 1945. [Class 100 (i)] [Also in Group XX] A pick-off device for printing-machines comprises a stationary vacuum chamber, a number of parallel spaced non-perforated belts which pass slackly about the vacuum chamber, and driving means therefor which ensures frictional driving engagement with the belts (e.g. a mangle roller drive) and openings in the vacuum chamber only between the belts and over a relatively small part of the vacuum chamber surface over which the belts pass. As shown the invention is applied to a photographic contact _printing and gas developing apparatus of the kind known under the Registered Trade Mark " Ozalid." The sensitized sheet 12 from a supply roll 13 and the original 14 are drawn into the machine by belts 16, 17 respectively and then are driven in contact through the printing station by belts 16 and a rotating cylinder 11 of heat-resisting glass, which surrounds a stationary mercury vapour lamp and reflector. The two sheets leave the printing stations and are peeled from off the cylinder 11 by an air blast at 28 so that they travel round the idle roller 19 to the pick-off device. This comprises two stationary vacuum chambers 20, 34, the difference from atmospheric pressure in the former being only half that in the latter. The exposed sheet 12 is held in contact with the belts 16 (which are perforated) by the suction of chamber 20 and passes upwardly to a second non-perforated belt system 31 which carries it across a gas developing tank 29 perforated at 30. The original 14 is driven by non-perforated belts 36 which are spaced apart on the cylindrical vacuum chamber 34 perforated at 35, said perforations being arranged to lie between successive belts, and is drawn away from the sheet 12 to pass around this cylinder from which is it removed by inclined wedges 67 (Fig. 2 not shown) placed on the cylinder 34 with their tapered edges below the level of the belts which they space apart, so as to fall face downwards into a tray 39. The belts 16 are driven by a roller 18 around pulleys 21-24, pulley 23 being a belt tension adjusted, while belts 17 are driven by roller 25 under and around a guide plate 26. Belts 36 are driven by a rubber covered roller 37 against which a spring mounted roller 38 presses to nip the belts which are thus driven without passing tautly around the stationary cylinder 34. This cylinder is attached to a framework by bolts passing through vertically elongated holes whereby the height of the cylinder above the rollers 37, 38-and hence the slackness of the belts 36-may be adjusted. Preferably to prevent dog-ears on the original, the belts 36 are driven at a speed 25 per cent greater than that of the belts' 16, there being a small clearance between the two sets of belts. If desired the wedges 67 may be replaced by wires of smaller diameter than the thickness of the belt which are attached to the plate 46 and soldered to the tank 34 so as to extend parallel to the belts. Their leading ends may be smoothed into the tank surface, and the wires may also serve to space the belts 36. U.S.A. Specifications 2,308,130 and 2,352,983 are referred to.