| 摘要 |
A disk cassette comprising a disk recording medium and a shell for rotatably storing the disk recording medium, wherein an area to be held (track) which is, at the time of insertion into a drive device, brought into contact with a cassette retainer installed in the drive device so as to be pressed by the cassette retainer is provided on both upper side parts of the shell, a plurality of grooves are provided in the area to be held, whereby a contact area between the cassette retainer and the area to be held becomes less and a friction resistance is reduced so that the disk cassette can be inserted smoothly into the drive device, and abrasive chips produced when the cassette retainer slides on the area to be held is discharged to the outside after being stored in the grooves. |
