| 摘要 |
PURPOSE:To prevent the discarding of printing data, by instantaneously detecting abnormality on the basis of the output of a sensor for detecting the marks on an ink ribbon printed at a definite interval to stop printing operation. CONSTITUTION:When the running movement of an ink ribbon 1 is normal, the marks on the ink ribbon 1 run in front of a sensor 4 and a sensor output signal 9 displays a waveform within a region of ink ribbon normal running A. At this time, signals (a), (b) do not exceed definite threshold value voltage while a signal (c) is held to a low-level. When the running movement of the ink ribbon 1 is stopped by some abnormality or not normally taken up by a take-up core and the marks on the ink ribbon 1 stop in front of the sensor, the sensor output signal 9 displays a waveform within a region of ink ribbon stop C and the level of the signal (b) exceeds the threshold value voltage and the signal (c) becomes a high-level. When the marks stop at a place other than the front surface of the sensor 4, the level of the signal (a) exceeds the threshold value voltage and the signal (c) becomes a high-level. |
