| 摘要 |
PURPOSE:To extend the service life of a magnetic disc by controlling the contact state between the magnetic disc and a magnetic head so as to attain stable recording/reproduction to an outer and an inner circumferential part of the magnetic disc and also prevent damage of the magnetic disc due to the magnetic head. CONSTITUTION:A fine adjustment mechanism 16 of head consists of a bracket 17 having a groove 17A in parallel with a hollow shaft 3, a slide piece 18 supporting a blade 14 to which a magnetic head 15 is fitted and slided in the groove 17A, and a shape memory alloy 19 fitted respectively to the left and right sides of the slide piece 18. The shape memory alloy 19 is connected to the magnetic head 15 via a drive circuit 24, a control (CPU) circuit 23, a dropout detecting circuit 21 and an amplifier 20. A stable reproduction output voltage is obtained by the magnetic head 15 at the outer and inner circumferential part of the magnetic disc 1Aa and the contact between the magnetic head 15 and the magnetic disc 1Aa is controllable, then damage of the magnetic disc 15 is prevented. |
