| 摘要 |
A device for detecting the terminal of a web such as an ink ribbon which is accommodated in a cassette, in which a hollow winding core on which the web is wound is formed of a transparent material. Into this winding core, a hollow fixed shaft having a void portion at a portion thereof is inserted so that the winding core is rotatable. A light emitting section and a light receiving section are positioned within the hollow fixed shaft and light is radiated through the void portion towards the winding core. The terminal of the web is connected to a light reflecting member, and the other end of the light reflecting member is fixed to the winding core, and the light reflecting member is wound upon the winding core more than one winding. As long as the web is wound on the winding core, the light from the light emitting section is reflected from the light reflecting member and the light receiving section receives the reflected light. However, as the light reflecting member is unwound and released from the winding core, the light from the light emitting section goes outside the winding core and the light receiving section becomes unable to receive the reflected light. Accordingly, the arrival of the web at the terminal is, detected by sensing that no light is received by the light receiving section.
|
