| 摘要 |
PURPOSE:To record and reproduce signals with a vertically magnetized medium having the same direction of magnetization on both sides by providing a means for discriminating the direction of magnetization of a vertical magnetic film. CONSTITUTION:When a disk 11 is rotated counterclockwise when viewed from right above the paper surface, the light delivered from a light source 45 is detected as shown by a signal A by a sensor of a detector 33 for direction of magnetization. While the disk 11 is turned over and attached again to a spindle motor 12. Then the disk 11 is rotated counterclockwise again. In this case, a signal shown in B is obtained by the sensor. Thus a signal different from A can be obtained. Thus it is possible to discriminate the direction of magnetization of the disk 11 to be recorded as soon as the disk is attached to the spindle after deciding the relation the direction of magnetization and the position of a window. |
