Opto-magnetic recording apparatus having over-write and non-over-write modes

Claim 1

An opto-magnetic recording apparatus having an over-write operation mode and a non-over-write operation mode and comprising: rotation means for rotating an opto-magnetic recording medium; magnet means for applying an initial auxiliary magnetic field to the recording medium during said over-write operation mode; a laser beam source for providing a laser beam for irradiating the recording medium; modulation means for pulsed-modulating the intensity of the laser beam, in accordance with binary information to be recorded, between a high level which is effective to record one of a bit having upward magnetization and a bit having downward magnetization on the recording medium and a low level which is effective to record the other of said bits thereon; recording magnetic field applying means for applying a recording magnetic field to the recording medium during said irradiation of the recording medium by the laser beam; and shifting means for supporting said magnet means and for shifting said magnet means between a first position for said over-write mode operation and at which said magnet means applies the initial auxiliary magnetic field to the recording medium when the recording medium is of an over-write type, and a second position for said non-over-write mode operation and at which said magnet means does not apply the initial auxiliary magnetic field to the recording medium when the recording medium is of a non-over-write type.