| 摘要 |
PURPOSE:To suppress the deterioration of data having been recorded by dropping laser luminous energy below the reproduced luminous energy or setting it to zero while a magnetic field given by a magnetic field giving device giving a magnetic field to an optical magnetic disk is rising. CONSTITUTION:The magnetic field giving device 2 gives a magnetic field to the optical magnetic disk 1, and a laser drive means 7 drives the laser of an optical head 3 which reads and writes information on the disk 1. According to the instruction causing a current zero by a controller 5, that of reproduced luminous energy and that of a servo gain at the time of reproduction, a magnetic field giving device drive means 6, the laser drive means 7 and a focus tracking servo amplifier gain adjustment means 8 are in reproduced stages. When a header signal reading means 4 reads out a header signal to a target sector, the controller 5 instructs the means 6 to give magnetic fields for recording and erasing, the means 7 to drop laser beams below those at the time of reproduction and the means 8 to increase gains. Thus the deterioration of data having been recorded can be suppressed.
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