| 摘要 |
<p>PURPOSE:To change the width of a groove for adjusting an air flow according to the number of rotations of a cylinder and to prevent the floating of a tape by axially dividing the rotating cylinder into plural ring members and disposing axially extensible piezoelectric elements between the respective ring members. CONSTITUTION:The ring 302 adjacent to the fixed cylinder 1 of the ring members 302-306 is fixed to a central shaft 5 and other rings are axially movable. At the time of a standard recording, the thickness of the piezoelectric element 9 and an applied voltage are set so as to generate a gap G1 between the members 302, 303, for instance. According to the increased speed of the rotating cylinder 3A for a high quality recording, the output voltage of a power source is changed to axially extend the piezoelectric element 9, lifts the rings 303-309, widen a gap G2 and increase an escaping air capacity. An air pressure between the peripheral face of the rotating cylinder 3A and a magnetic tape 2 is reduced to effectively bring the tape in contact with the magnetic head.</p> |
