| 摘要 |
PURPOSE:To execute recording under optimum conditions, in case when plural disks of different sizes have been used, by the same device, by providing a pressure-sensitive means for detecting a pressure of a discoid recording medium, and a rotation control means for controlling a speed of rotation in accordance with a detected pressure. CONSTITUTION:Pressure-sensitive conductive rubber 3 whose resistance value is varied by a pressure is attached in the shape of a ring to a turntable which has been attached to a spindle motor 1. In case when a disk size is smaller than a prescribed value, its weight is small and the pressure is small, therefore, a resistance value R1 of the pressure-sensitive conductive rubber 3 is high. Accordingly, the disk size can be discriminated. In this way, in each disk of different sizes, the recording density is made optimum by varying a rotating speed of the disk in accordance with sizes of the disk. In accordance with kinds of the disk diameter, the optimum rotating speed for recording on the disk is determined, and its determined speed is indicated on a spindle motor controlling circuit C.
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