| 摘要 |
PURPOSE:To shorten the tape take-up time with no increase of the voltage of re el motors nor improvement of their characteristics, by detecting the tape feed length, the number of revolutions of a supply reel motor and the diameters of both supply and take-up reels respectively. CONSTITUTION:The speed control of reel motors 8 and 9 is carried out to set the position of a tape loop within a vacuum column within a fixed range after detecting the position of the tape. The revolving directions of those motors are detected by a detection circuit 17 and with the output of a tachometer 14 of a capstan motor 3. While the length of a tape 7 fed forward is measured by an arithmetic circuit 18. The diameter of a supply reel 1 is obtained from the numbers of revolutions of the motor 3 and a take-up reel 2 and the diameter of the capstan 3. The diameter of the reel 2 is stored by the circuit 18, and the tape speed is increased until the coincidence is obtained between diameters of reels 1 and 2. Then the tape speed is slowed down to a level decided by the diameter of the reel 2. Thus it is possible to shorten the tape take-up time without increasing the voltage applied to reel motors or improving the characteristics of these motors.
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