Patent GB-616179-A (GB)
Title: Improvements in projection printing
IPC: G03B27/10
Filed: 1946-05-22
Abstract: 616,179. Projection printers for kinematograph films. TECHNICOLOR MOTION PICTURE CORPORATION. May 22, 1946, No. 15493. Convention date, Nov. 2, 1945. [Class 98 (i)] In kinematograph apparatus employing a belt having teeth which engage the feed perforations of film, means are provided for feeding the belt along a predetermined path, including a curved portion so that the pitch of the free ends of the register teeth differs from that of the ends which are attached to the belt, and for varying the curvature of the belt to adjust the pitch of the free ends of the teeth to the film feed perforations. Preferably the belt is made concave on the toothed side to accommodate shrunken films. As shown, a master film N to be copied and a blank film P to be printed upon are led from pay-out reels 21, 29 into contact with a toothed stainless steel belt 3, which is trained over sheaves 1, 2 between sets of flanged rollers 6 ... 9 and pressure rollers 11 ... 14 respectively, whereupon the films and belt traverse the optical axis of the projection printer comprising lamphouse 41, condenser 42, relay lens 43, aperture lens 44, projection gate apertures 56, 57, copying lens 46 and printing gate aperture 58, and after passing between rollers 7, 12.and 8, 13 respectively are led off the belt on to take-up reels 24, 26. Each of the pressure rollers 11 ... 14 is mounted on the free end of a pivoted arm and is urged against its companion flanged roller by one of springs 16 ... 19. The supply and take-up reels for both films and the sheave 2 are fixedly mounted on a backing plate 31, but the guide rollers for the films N and P are mounted on plates 61, 62 respectively adjustable on the plate 31 along the optical axis of the printer. The illuminating system 41 ... 44 is also mounted on the plate 61, while to keep the belt 3 taut the sheave 1 is mounted on a plate 33 slidable in vertical guides 34 on the plate 31 under the action of a spring 38 compressed between stops 36, 37 on plates 31, 33 respectively. To accommodate films N which have shrunk, a flanged roller 5 carried on a slotted arm 65 may be locked by a nut 66 in a position where it causes sufficient curvature of the belt immediately in front of the rollers 6, 11 to reduce the pitch of the free ends of the teeth to allow them to enter the feed perforations without damaging them. Specification 307,659, [Class 98 (ii)], is referred to. The Specification as open to inspection under Sect. 91 describes also, with additional drawings, modifications for printing a sound track along one margin of the film. A half-width belt having only one set of teeth is used, the rollers 5 ... 9 and sheaves 1, 2 are recessed to accommodate the belt, and each of the pressure rollers 11 ... 14 extends over the whole width of the film and is provided with a peripheral groove to accommodate the teeth on the belt. If two sets of 16 mm. prints are being made on 35 mm. stock the sound track for each set may be printed down the centre of the blank, using two such narrow belts, the rollers and sheaves being suitably grooved or recessed to accommodate the belts. This subject-matter does not appear in the Specification as accepted.