| 摘要 |
PURPOSE:To surely execute a recording and to prevent an unexpected polarity inversion at the time of reproducing by arranging a magnetic substance plate between a magnet and an magneto-optical disk, and retreating the magnetic substance plate from a point opposite to the magnet. CONSTITUTION:A magnetic substance plate 18 is arranged between a magnet 16 and a disk 1, and the plate 18 is fitted to a magnet supporting member 15 so as to be turnable approximately by 90 deg. from a magnet 16 just-under part along the circumference of the disk 1. At the time of recording, a signal onto the disk having an upward magnetism, when the magnetic substance plate 18 is turned to a position not to be opposite to the magnet 16, a line of magnetic force 17 is made downward just under the magnet 16, only the polarity of a part which a beam 14 beats is inverted from the upward to the downward, and the recording is executed. At the time of reproducing, the line of magnetic force 17 of the magnet 16 is shielded by the magnetic substance plate 18, and an external magnetic field is prevented from being impressed to the disk 1. Thus, a prescribed signal recording can be executed, and at the time of reproducing, the unexpected inversion of the polarity can be prevented, and a stable reproducing can be executed. |
