| 摘要 |
<p>PROBLEM TO BE SOLVED: To give a optimum back tension to a magnetic tape in a loaded cassette by constituting a magnetic tape recording and reproducing device to have a pressing force variable means for making pressing force of a brake member against a supply side reel shaft variable. SOLUTION: The device possesses a mechanical back tension imparting mechanism 36 for giving back tension to the magnetic tape 62 to be drawn out of a supply side reel with braking force given to the supply side reel shaft 33 by pressing the brake member 52 against the supply side reel shaft 33. A tension coil spring 54 whose one end is hooked to the brake member 52, has the other end hooked to an end of a sliding lever 84. Turning positions of a cam 40 differ from each other in accordance with a kind of cassette. The turning position of the came 40 is varied according to the size of a diameter D of a magnetic tape winding body 63. In accordance with the turning position of the cam 40, a position of the sliding lever 84 is varied, and the pressing force F of the brake member 52 against the supply side reel shaft 33 is varied, so as to give a optimum back tension to the tape.</p> |
