| 摘要 |
<p>PURPOSE:To move a tape guide by utilizing an electromagnetic force generated with a permanent magnet by supplying a driving current to a coil at the time of recording and reproduction, and to record and reproduce an excellent signal by controlling tape tension. CONSTITUTION:The permanent magnet 50 produces magnetic flux D by a closed magnetic path formed of a 1st yoke 51a and a 2nd yoke 51b. The magnetic flux D which is thus established crosses a gap 58. When the driving current is supplied in this state to the coil 52 in the direction shown in a figure, the coil 52 receives a rightward force to displaces the tape guide 56 to the right through a leaf spring 54 along a bush 55, and consequently the distance between a guide pin 8 and the tape guide 56 becomes large to tense a tape, to give back tension. The back tension applied to the magnetic tape is increased by supplying the driving current in the direction shown in the figure to displace the tape guide 56 to the right, and when the driving current is supplied in the reverse direction, the tape slacks and the back tension decreases.</p> |
