| 摘要 |
<p>PURPOSE:To give the stable prescribed tension even in the case a tape running state is stable and in the case it is in a transient state by detecting the speed-of- revolution information of a reel, and also, discriminating whether a speed of the tape is in a stable state or not. CONSTITUTION:Since a speed of a tape 1 is constant, periodic information outputted from a periodic information converting means 7 is information being proportional to a radius of a reel 2. From a multiplying circuit 9, torque information being proportional to the radius of the reel 2 is outputted by multiplying the periodic information by a constant. In this case, since a tape speed is in a stationary state, from a result of output of a comparing means 8, an output (torque information) of the multiplying circuit 9 is latched by a holding means 10, and outputted to a driving circuit 11. A reel driving device 4 is driven by the driving circuit 11, and an output of the holding means 10 is converted to torque. Accordingly, tension applied to the tape 1 becomes constant irrespective of the radius of the reel 2. Also, in the case the tape speed is in a transient state, by a result of output of the comparing means 8, the output of the multiplying circuit 9 latched at the time of a stable state is held by the holding means 10.</p> |
