| 摘要 |
PURPOSE:To detect the abnormal state such as catching of the ink ribbon of a printing head without damaging the mounting and detachment easiness of a ribbon cassette. CONSTITUTION:The lever 11 provided on the ribbon taking-up side 7 of a ribbon cassette 1, the spring 21 energizing the lever 11 so as to allow the leading end of the lever 11 to come into contact with the ink ribbon 5 taken up in the ribbon cassette 1 and the opening part 8 provided to the ribbon cassette 1 corresponding to the revolvable range of the lever 11 are mounted. A microswitch detecting the revolving quantity of the lever 11 generated when the ink ribbon 5 is pulled by an abnormal increase in the tension of the ink ribbon 5 through the opening part 8 to output an abnormal signal is provided on the side of a dot printer. |
