Nikon Corporation

Hiroya Ohkuma

Satoru Sanada

Tomohisa Hasumi

Shunji Hoshino

A magneto-optical disk apparatus in which a magneto-optical disk is loaded, data can be recorded on the magneto-optical disk, the data recorded on the magneto-optical disk can be reproduced and the data recorded on the magneto-optical disk can be erased includes a plurality of head devices for applying beams to the magneto-optical disk, the number of the head devices being an even number, a control device for controlling the plurality of head devices so that respective ones of the plurality of head devices apply beams to different ones of a plurality of annular areas on the magneto-optical disk, the number of the annular areas being the same as the number of the head devices, the control devices having a plurality of supporting devices for supporting each two of the plurality of head devices thereon, the two head devices supported on the plurality of supporting devices being supported so as to apply beams to two recording areas which are not adjacent to each other, and an applying device for applying a magnetic field to the plurality of annular areas, the applying device applying a magnetic field to the magneto-optical disk in a predetermined direction when the data is recorded on the magneto-optical disk, and changing the direction of the magnetic field applied to the magneto-optical disk to the direction opposite to the predetermined direction when the data recorded on the magneto-optical disk is erased.

Multi-head magneto-optical disk apparatus

Optical recording/reproducing apparatus of the 2-head or 3-head type uses a simplified controller but is nevertheless capable of high-speed read-after-write check. In a 2-head embodiment a switching circuit supplies either a reproducing output of a recording head or a reproducing output of a reproducing head to a signal processing circuit selectively. When the reproducing output of the reproducing head is supplied, a signal generator supplies a signal to the signal processing circuit corresponding to the reproducing output of the recording head. In a 3-head embodiment a circuit compares identification signals in reproducing outputs of an erasing head and a recording head, respectively, and supplies the recording head with data to be recorded from a FIFO memory. A 3-head embodiment may also use a switching circuit for supplying either a reproducing output of an erasing head or a reproducing output of a reproducing head to a signal processing circuit.

Signal processing circuit for magnetooptical record/reproducing apparatus

In an optical disc device, a plurality of heads provided with actuator means for inclining the direction of application of a beam applied to the surface of a disc within a predetermined range are secured onto a slider movable in the radial direction of the disc, and provision is made of detecting means for detecting the positions or the tracking errors of the beams of the plurality of heads, and slider control means for position-controlling the slider on the basis of the detection signal of the detecting means so that the directions of application of the beam spots by the actuator means are in a predetermined relation.

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Tokyo, Japan

Hiroya Ohkuma