| 摘要 |
PURPOSE:To avoid sticking of dust to a disk by shifting up an down a seal ring in response to a shutter to close a gap between the disk and a cartridge. CONSTITUTION:When a shutter 6 is turned, a projected part 6' of the shutter 6 moves to a position B from a position A. While a projected part 9 of a seal ring 8 is engaged with hollow parts 10 and 10' of disk drive holes 3 and 3' of upper and lower covers 1 and 2, respectively. Thus the rotation of the shutter 6 is suppressed. Therefore the ring 8 is moved up and down by the part 9 which moves in parallel to the covers 1 and 2. Thus the ring 8 is separated from a disk 5. The ring 8 usually has a close contact with the disk 5 by supporting it from upper and lower sides. As a result, the disk 5 is exposed only at an area corresponding to the inner diameter of the ring 8, and the greater part of the ring 8 including the recording surface and excluding said exposed area is cut off from outside. This prevents the attachement of dust to the disk 5. |
