Patent ID: 7287716

Claim:
A magnetic tape cartridge comprising: a cartridge case, and a single reel which is rotatably housed in the cartridge case, the single reel having: (a) a reel hub around which a magnetic tape is wound and a lower part of which is closed by a bottom wall, (b) upper and lower flanges respectively extending radially outward from the outer peripheries of the upper and lower ends of the reel hub, (c) a reel gear provided in an annular form at an outer peripheral portion of a lower surface of the bottom wall of the reel hub so as to be meshable with a driving gear of a drive-side rotary driving member provided in a drive device; and (d) a metal plate which is to be magnetically attracted by the drive-side rotary driving member, wherein the metal plate is disposed on the bottom wall of the reel hub in a manner such that an outer periphery of the metal plate is positioned under the inner facing surface of the reel gear.