| 摘要 |
PURPOSE:To simultaneously execute erasing, re-recording and to shorten a re-recording time by installing permanent magnets whose polarities are reversed at the symmetric positions on the upper surface over a disk and disposing an optical magnetic disk head moving by facing said magnets and a following type disk head on the lower surface. CONSTITUTION:The permanent magnets 12 and 14 whose polarities are reverse to the disk 10 are installed at the opposite position on the surface of the disk 10 in the radial direction, and the optical magnetic head 16 moving in the radial direction of the disk 10 by facing the magnets 12 and 14 and the following type head 18 are disposed on the lower surface of the disk 10. Thereon objective lenses 21 and 22 are provided. An optical disk is used for the disk 1 constituted in such a way, and the head 16 records and reproduces data, while the head 18 erases data. For executing said actions, an erasure address is transmitted to the head 8 from an erasure range specifying circuit 20, and the head 16 is caused to rewrite data. |
