| 摘要 |
<p>PURPOSE:To eliminate fluctuations of tape tension and shift a tape at high precision by feeding power to the drive motor of each reel at a rate in response to the tape radium wound on each reel. CONSTITUTION:A magnetic tape 5 is shifted from one reel 4 to the other reel 3 via a tension sensor 9, magnetic head 6, and a speed tachometer roller 8 by the drive of motors 1, 2. Rotation quantities of reels 3, 4 are detected by tachometers 11, 12, and the minute rotation of the speed tachometer 8 is detected by a fine tachometer 10. The tape length wound on the reel 3 is equal to the tape length having passed the speed tachometer 8, therefore the radius of the reel 3 can be determined by comparing both rotation quantities. It is the same for the reel 4. A control unit 16 calculates drive currents of motors 1, 2 by using reel radii via a control algorism and can control the movement of motors 1, 2 via a power amplifiers 14, 15 thus tension fluctuations can be eliminated.</p> |
