Optical gate for scanning film material has toothed roller conical running surface with largest diameter at bounding roller edge so roller's maximum peripheral speed is at this point.

摘要

The device has a film channel (4) for passing film material (5) and an optical scanning window (6,7). Toothed rollers (10,20) before and after the film channel each have a conical running surface (12,22) without a gear rim and a cylindrical running surface (11,21) with a gear rim. The largest diameter of the conical surface is at the bounding roller edge so that the gear roller has its maximum peripheral speed at this point.