Patent ID: 7032853

Claim:
A recording tape cartridge comprising: a reel having a hub around whose outer peripheral portion a recording tape is wound, the reel being accommodated within a case; a reel gear formed in an annular form which is coaxial with the reel, and provided at an end surface of the hub, and able to mesh with a driving gear of a drive; and a pull-out portion which is formed in the case and has an opening for pulling-out of the recording tape, wherein an annular convex portion projects coaxially with the hub at the end surface of the hub, and an end surface of the annular convex portion is a reference surface which abuts a positioning portion of the drive device and carries out positioning of the reel in an axial direction of the reel, and when the recording tape is in use, the reel rotates around an axis due to driving force of the driving gear which meshes with the reel gear, in a state in which the reel is positioned in the axial direction of the reel and is raised up within the case.