GB629614A - Improvements in or relating to photo-copying machines - Google Patents

Abstract

629,614. Photographic contact-printing apparatus. OZALID CO., Ltd., and BLICK, F. Oct. 31, 1946, No. 32396. [Class 98 (ii)] [Also in Group XXIV] Relates to contact-printing apparatus of the kind comprising a hollow transparent cylinder with its axis horizontal, a light source within the cylinder, guide rollers disposed around the cylinder and rotatable about horizontal axes, and an endless band carrier mounted on the guide rollers and embracing the major part of the outer surface of the cylinder but allowing a feed-gap for insertion between the carrier and the cylinder of a transparency sheet to be copied and a light-sensitive sheet to be exposed. The transparent cylinder is slung cradlefashion by the endless carrier, the guide rollers above the axis of the cylinder are carried by a hinged frame pivoted at one side of the cylinder to uncover the upper portion therof, and the frame has means operable on movement of the frame to maintain tension in the carrier. The carrier preferably comprises a number of parallel endless belts. As shown in section, Fig. 3, a mercury-vapour lamp 22 is resiliently and detachably supported within a glass cylinder 34. Parallel endless belts 46 pass around rollers 35, 36, 48, 49 and the cylinder 34 to engage the greater part of the surface of the latter. The roller 35, to which a drive is imparted, has end hubs which engage and partially support and drive the cylinder 34; they may be made of resin impregnated fibrous material, at least on the engaging surface. Rollers 35, 36 rotate in bearings in a main frame, but rollers 48, 49 have end bearings in a subframe 55 pivoting about a rod 57 to swing into an inoperative position (dotted lines) for access to the cylinder 34. In this position, the belts 46 may engage a tube 58 fitting loosely on the rod 57. Slack in the belts, is thus minimized, and is taken up by mounting the ends of the shaft 51 of the roller 49 in blocks 62 sliding in slots 63 in the ends of the subframe 55, and urged to tighten the belts by a screwadjusted spring 64. Fingers 69 on the tube 58 project between the belts to keep them in correct alignment. In operation, the roller 35 is driven by an electric motor through an infinitely variable speed gear-box, and drives the belts and the cylinder 34 so that the latter rotates anticlockwise. A light-excluding member 103 may carry a felt wiper 104 for the inner surface of the cylinder 34. Sensitive paper, which may be supplied from a roll 100, is fed with the matter-to be copied over a tray 95 and under a resilient finger-guard 102 into the apparatus, where they are carried round between the belts 46 and the cylinder 34. On emerging they are stripped from the cylinder by resilient prongs 90 on a comb 101 and guided out by a tray 91. The rollers and cylinder may be enclosed by a metal frame extending between housings for the driving motor, gearbox, and transformers for the lamp.