| 摘要 |
PROBLEM TO BE SOLVED: To reject the disks recorded with abnormal servo signals without fail. SOLUTION: Two magnetic heads 5 are attached on the tip end of the suspension arm 6. Each of the upper head sensor 31 and the lower head sensor 32 has a light emitting element and a photodetector and is connected to a controller 7. Each of the sensors 31 and 32 sends the received light volume signals showing the amount of the light reflected on the magnetic head 5 and received by the photodetector to the controller 7 while writing servo signals. The controller 7 calculates the height, the up-and-down moving range, and the frequency of changes of the magnetic head 5 based on the input received light volume signals. A discriminator 7b determines whether or not the calculation results are within the range set in advance. When it decides that the calculation results are within the limit, the controller 7 continues its servo writing. However, when the calculation results are decided to be out of the range by the discriminator 7b, the controller 7 controls the drive of the magnetic head 5 to stop the servo writing. COPYRIGHT: (C)2007,JPO&INPIT
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