| 摘要 |
PURPOSE:To move a magnetic head to an accurate track position, by providing (n) slits on a shielding plate to detect the reference position of a magnetic head position corresponding to a track, and counting the number of times of the detection of a photoelectric sensor. CONSTITUTION:Assuming that the position of the shielding plate 5 corresponding to (n) tracks that is, a track pitch is set at 0.559mm, the slit 5-1 having such pitch is formed. Meanwhile, a mask 4-1 in which slits 4-2 are formed respectively at the light emitting part and the light receiving part of the photoelectric sensor 4 is attached, and a stepping motor 3 is driven by setting four steps as one block. For example, when it is desired to move the magnetic head to a track #4, the photoelectric sensor 4 detect four times of ON signals and four times of OFF signals, and the OFF signal is detected when the stepping motor 3 stops, and it is possible to detect the stopping position of the magnetic head accurately by detecting the number of times of the ON and the OFF signals. In such a way, the movement of the magnetic head can be obtained accurately.
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