Conventionally, a disk device of a so-called slot-in type is configured to directly load and unload a disk medium without placing the disk medium on a tray. A disk stopper is provided in the disk device of this type, and the disk stopper abuts against the peripheral edge of the disk medium to regulate the loading position of the disk medium. Recently, in order to correspond to a plurality of kinds of disk media of different diameters, the disk stopper is configured to be reciprocally movable in the loading-unloading direction (for example, see Patent Document No. 1).
When the disk medium is loaded into the disk device, the disk stopper moves to a predetermined position corresponding to the diameter of the disk medium, and abuts against the peripheral edge of the disk medium, so as to position the disk medium. Further, when the positioning the disk medium is completed, the disk stopper departs from the disk.
Patent Document No. 1: Japanese Patent Publication No. 2955116 (Pages 4-5, FIGS. 1-3).