| 摘要 |
A film drive control system includes a light source that directs a beam at a photographic filmstrip and a sensor located such that it detects this light source depending on whether or not the light source is blocked by the passage of the photographic filmstrip. The filmstrip includes perforations that indicate frame exposure areas. The filmstrip is advanced one frame at a time by first moving the film forward at a relatively high velocity until the leading edge of the perforation passes the sensor, then reducing the velocity in the forward direction until the trailing edge of the perforation passes the sensor. The filmstrip is then moved in the film reverse direction at a reduced velocity until the trailing edge again passes by the sensor, at which time the filmstrip is halted.
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