| 摘要 |
<p>PURPOSE:To stabilize the rotary performance at a constant speed travelling by constituting a supply voltage to a take-up driving motor controllably in accordance with a travelling position of tape at the constant speed travelling. CONSTITUTION:Plural magnets 13 are connected in one body below reel gears 7, 8 on reel stands 5, 6 and the switching of a magnet pole by the rotation of the magnet 13 is detected by a magnetism sensitive element 14. A reel motor 9 does not have a governor controlling the number of rotation, and the number of rotation can be changed by changing a supply voltage, and the rotary torque can be changed by changing a voltage at a constant rotation. The rotary number of the reel stand is detected by receiving the pulse according to the switch of the magnet 13 and the pulse interval is received in digital and converted to an analog value by a D/A converter and the voltage is supplied by a driving circuit to the reel motor 9. Consequently, the fluctuation due to drive of a capstan and a pinch roller is decreased by changing a take-up tension in matching with the change of back tension just before a capstan 3 to stabilize the rotary performance.</p> |
