| 摘要 |
PURPOSE:To decrease a reproduced error rate by providing a means to execute an erasing operation to a non-recording part, and applying a function to align the direction of the magnetization of the non-recording part. CONSTITUTION:First, a controller 6 decides whether or not a changeover switch 7 is closed. When the switch 7 is decided to be closed, next, an electromagnet 3 is driven so as to generate an erasing magnetic field. When an AT polarity switching signal is sent to the change-over switch 7 inside the controller 6, a laser beam spot radiated on a land 21 is shifted to a group 20. Continuously, the beam spot shifting is suitably executed. After group tracking is made OK, the operation to set laser power at erasing power is executed, thereafter, the group erasing is executed while group tracking is being executed. Thus, even when the optical beam spot is partially stuck to the non-recording part at the time of reproduction, it does not cause the noise mixture to the regenerative signal, and the reproduced error rate can be drastically decreased. |
