| 摘要 |
<p>PURPOSE:To secure the detection for the tape roll-in by having the comparison between the reference value set previously and the value obtained by adding together the both rotational frequencies of the take-up and supply reels in which the value increases suddenly when the tape is rolled in, thus realizing the simple and low-cost manufacture along with the miniaturization. CONSTITUTION:When the tape features the normal running, the output of adder 5 is smaller than the output of reference pulse generator 6. Thus no output is caused from comparator 7. In case the tape is rolled in to the capstan, take-up reel 2 stops its rotation at the beginning of the roll-in of the tape and then starts the rotation in the opposite direction to the tape roll-in. The small diameter of the capstan increases immediately when the tape is rolled in, and accordingly the running speed of the tape increases. As a result, both reel turntables 1 and 2 function as the supply reel turntable, and the rotational speed increases at an increasing tempo. Thus the sum value of both reel turntables 1 and 2 increases suddenly to be larger than the value of generator 6, and then comparator 7 generates the output to discontinue the operation of the mechanism.</p> |
