Magnetic head lifting device for magneto-optical recording/reproducing apparatus including drive means responsive to a PLL circuit

Claim 1

A magnetic head protection control device for a magneto-optical recording and reproducing apparatus which includes an optical head for recording information signals on, and reading information signals from a magneto-optical disk and a magnetic head for applying a magnetic field to the magneto-optical disk during the time that the optical head is recording information on the magneto-optical disk, wherein the magnetic head protection control device comprises: an elastic arm for mounting the magnetic head at one end portion of the arm and biasing the magnetic head in a direction toward contacting a surface of the magneto-optical disk, and the elastic arm also being movable radially with respect to the magneto-optical disk; a phase-locked loop circuit connected to the optical head to be supplied with the information signals reproduced by the optical head from the magneto-optical disk, the phase-locked loop circuit generating a lock signal only when the phase-locked loop circuit becomes synchronous with a clock signal in the reproduced information signals from the magneto-optical disk; and driving means connected to the phase-locked loop circuit for driving the elastic arm to lift the magnetic head away from the surface of the magneto-optical disk in the absence of the lock signal generated from the phase-locked loop circuit and to lower the magnetic head toward the surface of the magneto-optical disk upon generation of the lock signal from the phase-locked loop circuit.