Flexible disk liner arrangement capable of preventing the ingress of dust

A flexible disk comprising:

• a generally disk-shaped sheet-like magnetic recording medium;
• a rotation supporting hub attached to a center portion of said magnetic recording medium;
• a jacket enclosing said magnetic recording medium in a manner such that said magnetic recording medium is rotatable on said rotation supporting hub;
• and
• a generally annular liner attached to an inner surface of said jacket,
• wherein said jacket is provided with an opening to expose said rotation supporting hub, and a protruding portion is formed on an inner surface of said jacket in a vicinity of an edge of said opening;
• wherein an inner peripheral portion of said liner extends over said protruding portion toward said rotation supporting hub such that a free end of said inner peripheral portion extends past said protruding portion toward said rotation supporting hub and such that said free end of said liner contacts an outer peripheral portion of said rotation supporting hub and closes a gap between said rotation supporting hub and the edge of said opening in said jacket to thereby prevent ingress of dust through said gap;
• and
• wherein said protruding portion comprises a plurality of projections spaced apart from one another in a circumferential direction and extending from and around the inner surface of said jacket in the vicinity of the edge of said opening in said jacket.