Disk recording-playback device, disk tray for use in the device, and method of ejecting the tray

Provided forwardly of a stacker accommodating trays in a plurality of stages for placing a disk on each tray is a recording-playback unit which is movable upward and downward for recording or reproducing data on or from the disk. A clamp plate covering the recording-playback unit is pivoted to the unit. When one of the trays is to be ejected from the stacker, the recording-playback unit is moved upward or downward to a level where the disk carrying face thereof is displaced from the tray to be ejected, to block the path of movement of the tray to the recording-playback unit with the clamp plate or the recording-playback unit, and the tray is thereafter ejected.