| 摘要 |
PROBLEM TO BE SOLVED: To obtain an information recording and/or reproducing apparatus by which information can be recorded and reproduced with high accuracy. SOLUTION: A gap sensor 38 which detects the circularity or the eccentricity amount of a rotation part 37 is installed near the rotation part 37 which is situated between an air bearing 22 and a disk 24. The output of the gap sensor 38 is input to a second control circuit 34. The gap sensor 38 uses the interference of irradiation light with reflected light by a semiconductor laser light source. The deflection amount of a rotating body 22a in the bearing 22 and the circularity of a flange part 23a in a clamp part 23 are detected simultaneously. Whenever the rotation part 37 makes one rotation, one index pulse signal is output. The second control circuit 34 calculates an asynchronous deflection amount on the basis of the circularity or the eccentricity amount, of the rotation part 37, detects by the gap sensor 38. The asynchronous deflection amount is converted into the angle of rotation of a shaft 26a in a second spindle motor 26 so as to be output to a second drive circuit 32. The second drive circuit 32 turns and drives the shaft 26a in the second spindle motor 26 by the asynchronous deflection amount. Thereby, the actual position of a head 29 is corrected.
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