Dual sprocket contact motion picture film printer

摘要

A dual sprocket contact motion picture film printer maintains film steadiness when running a film negative in contact with an unexposed raw stock film. The perforations along both sides of the films are tensioned against sprocket teeth of a full fitting sprocket on one side and a shrinkage sprocket on the other side of the dual printing sprocket. A fluid chamber is positioned adjacent the printing sprocket on the in-feed side of the printer. The films pass through the fluid chamber before passing through the aperture of the printer. A vacuum pressure applied from one side of the chamber tensions the negative against the sprocket teeth and a positive fluid pressure applied on from an opposite side of the chamber tensions the raw stock against the sprocket. The films are self-aligned by the fluid forces maintaining equal tension on both sides of each film strip as the films pass the aperture of the film printer. The system also includes an upper gate roller to ensure that the films are fully laid down onto the sprocket teeth and against the root of the sprocket before they pass through the aperture. In another embodiment, an elongated fluid nozzle applies pressure to the overlapping film strips before they pass through the aperture to remove any fluid trapped between the films prior to exposure. In a further embodiment film tension is equalized by self-aligning rollers that contact the films before passing to the sprocket and then to the aperture.