| 摘要 |
PURPOSE:To prevent an error in retrieving a desired frame by braking a driving and a driven shaft at the same time when the mark of the desired frame is detected, and releasing the braking to the driven shaft temporarily when the number of revolution of the driving shaft exceeds a set value during the braking and thus giving the film a sag. CONSTITUTION:When the number of the desired frame to be retrieved is inputted to an input device 21, a CPU20 judges whether the film is to be forward or backward fed and rotates a motor 8 or 10 to feed the film at a high speed. When the mark is detected by a mark detector 17, brakes 12 and 13 brake the driving and driven shafts at the same time. When the number of revolution of the driving-side motor attains the set value, the driven-side brake is turned off temporarily and turned on again after a set time T2 is elapsed to give the film a sag when a tape is stopped. This time T2 is set experimentally to adjust the extent of the sag, and consequently an error in counting due to the reciprocal oscillation of the frame marks for counting is eliminated to improve the retrieval precision. |
