PURPOSE: To enable to smoothly take up a belt form material, by a method wherein the first reflecting part for reflecting light emitted from a light-emitting part and the second reflecting part for constantly reflecting the light from the light-emitting part at any rotating position are provided at a part on the innermost side of a belt form material.

CONSTITUTION: When a take-up shaft 29 is rotated, a winding bobbin 26 is rotated with a hollow fixed shaft 22 as a center, an ink ribbon 27 is fed in the direction of an arrow, and is gradually let out from the core 26. In this case, since a light-reflective tape 28 is wound around the outer peripheral surface of the bobbin 26, the light emitted from the light-emitting part 23 passes through a notched part 25 and the transparent bobbin 26, and is constantly reflected by the tape 28 to be received by a light-receiving part 24. Immediately before the moment the ink ribbon 27 is completely taken up, the tape 28 wound at least one time around the bobbin 26 is separated from the bobbin 26, and the light emitted from the part 23 is released to the exterior through the notched part 25 and the transparent bobbin 26, so that the light is not received by the part 24.