| 摘要 |
PURPOSE:To suppress excessive variation in tape tension by detecting a value proportional to a winding diameter and a running direction, setting the condition of torque command variation to a reel motor from the detected run-direction value, and comparing the detected winding diameter with a basic winding diameter value for generating a torque command value and specifying the torque command. CONSTITUTION:A one-turn detection signal is outputted to a detection circuit 12 on every turn of a take-up side reel motor 15. The run distance of a tape is known from rotations of a reversing roller 10. At this time, the number of pulses of a photointerrupter 11 is counted at the intervals of generation of one-turn detection signals to obtain the value proportional to the winding diameter of the tape 2. A run-direction detecting circuit 16 checks the run direction; when the checked direction shows a normal run, the detected winding diameter value is inputted to a memory 18 if the detected winding diameter value is larger than the contents of the take-up side memory 18 and the take-up side torque command is varied into a value based upon the up-to-date detected winding diameter value and outputted to a driving circuit 14. The direction of variation in detected winding diameter value is set on the basis of the result of the check on the run direction and only the detected winding diameter value satisfying the condition is employed as information for varying the torque command by a program. The generated torque of a supply side reel motor 6 is the same as the description above mentioned. |
