Patent GB-681388-A (GB)
Title: Apparatus for stripping and printing motion picture films with improved registration
IPC: G03B27/08
Filed: 1950-02-14
Abstract: 681,388. Colour photography; printing by imbibition and photographically by contact; kinematograph sprockets. REPUBLIC PICTURES CORPORATION. Feb. 14, 1950 [Feb. 18, 1949], No. 3753/50. Classes 97 (i) and 98 (ii). Apparatus for photographic contact or imbibition printing of motion picture films or for separating a strippable layer from one film strip and transferring it to another film strip, each of a pair of strips used having at least one row of feed perforations of nominally identical pitch, comprises a wetting tank for bringing the feed perforation pitch of one strip to the same value as that of the other strip; a registration station having guide means between which the two film strips pass in contact with each other and with at least one surface of the guide means in contact with and movable with one strip, registration pins in the strip contacting surface of the movable guide means, and bearings in which the registration pins are movable relatively to the surface of the guide means ; and operating mechanism that projects and retracts these pins with respect to the surface of the guide means in timed relation with the movement of the film strip contacting said guide means, said registration pins being of a size when projected to engage fully the feed perforations of the two film strips and thus compel accurate registration of corresponding frame areas of the two film strips. As shown, a multilayer film 20 is fed from a spool 15 by a driven sprocket 21 over one of a set of rollers 23 into a water tank 17 having heaters 27 and then passes out over another roller 23 to a sprocket 28 from which it moves into contact around a roller 34 with a blank support film 30 carried on a spool 10 and fed around a guiding roller 33, the contacting films then passing tangentially to a driven sprocket 36 having radially movable pins or teeth which register the two films accurately, a roller 38 carried on an anti-clockwise loaded pivoted lever and having grooves for accommodating the registering teeth being arranged to press the films onto the sprocket. The registered films then pass between pairs of presser rollers 45, 46 and then between a presser roller 47 and a sprocket 48 driven at a greater speed than sprocket 36 to maintain the films in tension, the drive being either through a friction clutch to permit slipping or the sprocket being mounted slidably along the length of the films so as to maintain a constant tension. The films are then fed round a wheel 50 of large radius into a compartment 53 where the blank film with its adhering emulsion layer, loosened from the multilayer film, is stripped from said multilayer film under water in a tank 54 around rollers 55, 56, the two films 20, 30 then being fed over pairs of rollers 58, 57, the upper rollers of each pair being driven, and washed by sprays as 59, whereafter they are fed to drying compartments 61, 60 respectively containing driven upper rollers 78, and are finally wound up on driven take-up spools 62, 63. The apparatus may be used for imbibition printing by employing as the film 20 a printing matrix and making the bath 17 a dye bath. In the case of photographic contact printing, the negative to be printed is used as the film 20 and printing is effected in the path between sprockets 36, 47. If the blank film 30 is initially of identical pitch with or has shrunk more than the film 20, it may be appropriately swollen to permit accurate registration of the two films by passage through a heated water bath. The registering sprocket 36 comprises two flanges 92 secured to a hub 90 and provided with teeth 94, which engage only the leading of the two transverse edges of each perforation, and radial rectangular grooves in the outer faces of the flanges at distances of every fourth tooth location in which are located the rectangular shanks of teeth 95, which are guided for movement only longitudinally of the slots by rings 103 bolted to the flanges at 104. The teeth carry at their innermost ends lateral projections which engage in a cam slot 107 formed in a block 108 secured to the frame supporting the sprocket, said slot having an eccentric portion at 107' adjacent the roller 38, so that only one tooth 95 engages the two films at any time to effect registration.