Recording tape cartridge and rotation locking structure

A recording tape cartridge comprising:

• a reel around which a recording tape is wound;
• a case in which the reel is accommodated such that the reel is rotatable around a reel axis line;
• a reel side gear provided in the reel, that is configured to include a plurality of piece taper teeth, in each of which a first mesh surface oriented in a rotation direction of the reel when the recording tape is wound is substantially parallel to the reel axis line direction and a second mesh surface oriented in a rotation direction of the reel when the recording tape is pulled out is inclined with respect to the reel axis line direction, the plurality of piece taper teeth of the reel side gear being arranged in the reel along a circumference which is coaxial with the reel;
• a case side gear provided in the case or a brake member which is supported so as not to be able to rotate with respect to the case, that is configured to include a plurality of piece taper teeth formed to be able to mesh with the piece taper teeth of the reel side gear, the plurality of piece taper teeth of the case side gear being arranged in the case or the brake member along a circumference which is coaxial with the reel, and a mesh state of the reel side gear and the case side gear and a mesh release state of the reel side gear and the case side gear being able to be acquired by the case or the brake member and the reel being relatively moved in the reel axis line direction;
• and
• a mesh holding section that maintains the mesh state of the reel side gear and the case side gear when the recording tape is not in use.