| 摘要 |
<p>PURPOSE:To always obtain stable tape tension by controlling the tape tension to be kept constant by a driving means by using the output signal of a winding diameter detector and the addition output signal of a variation detector. CONSTITUTION:The position information of a magnet 4 fitted to a tension lever 2 are converted to a voltage by a magnetic sensor 5 and applied to a differential amplifier 8 and the voltage proportional to the change part per unit time of the tape tension is outputted. The signal of a frequency proportional to the tape velocity is detected by a timer roller 12 and a photocoupler 13 and applied as a timer roller FGb to a winding diameter control circuit 11. A reel FGa as the signal of a frequency proportional to the rotating speed of a motor 10 is also applied to the winding diameter control circuit 11. In the winding diameter control circuit 11, according to the ratio of the frequencies between the timer roller FGb and reel FGa, the tape winding diameter is decided and the voltage corresponding to the winding diameter is outputted and added with the output signal of the differential amplifier 8. Then, the driving force of the motor 10 is controlled through a driving circuit 9. Thus, the stable tape tension always is obtained.</p> |
