Patent GB-656798-A (GB)
Title: Method and apparatus for transferring a photographic emulsion layer from a perforated film strip to another similarly perforated film strip
IPC: G03C7/20
Filed: 1948-08-10
Abstract: 656,798. Stripping and transferring layers from multilayer colour photographic films. KODAK, Ltd. Aug. 10, 1948, No. 21053. Convention date, Feb. 17. [Class 98 (ii)] In a process for transferring an emulsion layer strippable from a perforated film support 10 to another similarly perforated film support 22 wherein the two film strips are caused to adhere to one another and to be registered by means of their perforations prior to such transfer, the strips are pressed into intimate contact as by rubber-covered rollers 40, 41 before they are passed to a first registering sprocket 47 and are held in tension between said sprocket and a second registering sprocket 57, which as described is driven at a greater speed than the first sprocket. Preferably the first sprocket is positively driven and the second sprocket is frictionally driven. The registered adhered films may be passed over third, fourth and fifth sprockets 81, 87, 89 which are positively driven at the same speed, and an idler wheel 98 positioned between the third and fourth sprockets and mounted so as to take up film slack, the fourth and fifth sprockets being disposed so that a free loop of film is suspended between them and may be adjusted in size to control the bonding period, after which stripping is performed over a roller 96. The five sprockets 47, 57, 81, 87, 89 are provided with two rows of teeth, one row filling the perforations longitudinally and laterally and the other row only longitudinally and the teeth engage sockets in rollers 48, 58, 82, 86, 88 which are normally spring-pressed against the sprockets, but may be moved away from them for threading. To prevent damage to the teeth through faulty meshing of sprockets and socket rollers meshing gear-wheels are mounted coaxially with them, the said gear teeth also preventing the sprockets and rollers from pressing the films together. The roller 40 is moved away by a spring from the roller 41 when the apparatus is not running and is returned by a solenoid-controlled bell-crank when the driving circuits are closed. After registration on the sprockets 47, 57, the adhered strips 10, 22 are lightly pressed together by pairs of rubber rollers 90, 91 and 92, 93, or each pair may be replaced by a single roller and a presser plate. After leaving the rollers 92, 93 surplus water is removed by an air blast squeegee 83. To prevent lateral movement of the adhered films a film guide track recessed to locate the film is arranged to extend from sprocket 47 to sprocket 57, the track being apertured to permit the film engaging members to protrude through it. To ensure maintenance of lateral registration of the films between the two sprockets 47, 57 whilst bonding is still only weak, there is provided an idler sprocket 61, having only a single row of teeth filling the perforations only laterally and in line with the laterally registering teeth of sprockets 47, 57 and a meshing socket roller 62. All the members in the tank 80 are secured to a mechanism plate except a weighted roller 21 which may be raised or lowered to alter the length of the multilayer film 10 in the tank and hence the wetting time of the film. To remove air bubbles from the films when they enter the tank 80 and immediately before they are pressed into contact, jets of water are directed against them while submerged, and the films may be led round cleaning rollers which are spray-fed with water (Fig. 2, not shown) and against which they are pressed by a movable roller. Specifications 574,137, 574,138, 574,164, 582,436, 582,438 and 582,439 are referred to.