Patent ID: 7377462

Claim:
A single reel tape cartridge, comprising: a single reel disposed inside a main case for taking up a magnetic tape; the reel being a plastic molding formed by integrally molding a lower flange and a boss for taking up the magnetic tape; a reel lock mechanism formed between a bottom wall of the boss and an upper case of the main case for keeping the reel not in use in a locked state so as not to rotate; an unlock tool disposed on an inner face of the bottom wall of the boss for unlock operation of the reel lock mechanism; an exit port formed on the bottom wall of the boss in an outer circumferential region so as to connect inside and outside; and an operating nail included in the unlock tool and facing a lower face of the case from the exit port, wherein the boss is molded integrally with a bridging piece which seals at least a part of the exit port, and during molding of the lower flange and the boss, a melted molding resin is made to flow in radial direction between the boss and the lower flange through the bridging piece at a region where the exit port is present.