| 摘要 |
PURPOSE:To prevent troubles concerning broken characters, ribbon winding or the like from occurring due to folding of an ink ribbon and obviate wasting of the ribbon due to breakage of the ribbon, by providing a means for detecting an abnormality in the width or the thickness of the ink ribbon, at a passage for the ribbon. CONSTITUTION:In the exterior of a ribbon guide 12a of a ribbon cassette 12, photosensors 16a, 16b are provided oppositely to side edge parts E1, E2 of the ink ribbon 7, and are connected to a controlling part 18. The photosensors 16a, 16b are constituted of light-emitting elements A1, B1 and light-receiving elements A2, B2 supported respectively by support members 17a, 17b, which are fitted to a frame 13. In normal condition, the photosensors 16a, 16b are shielded by the side edge parts E1, E2 of the ribbon 7. When the ink ribbon 7 is folded, either of the photosensors 16a, 16b detects the reduction in the ribbon width, ad either of detection signals c1, c2 is sent to the controlling part 18, whereby the printing operation is stopped, and an alarm buzzer is operated. The folded state of the ink ribbon 7 can be detected also through the thickness of the ribbon.
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