摘要 |
In a single-pass, multi-head thermal printer, wherein a recording material is transported along a transport path, a mark sensor is disposed in proximity to each of a plurality of thermal heads. The sensors detect positioning marks which are provided on the recording material at constant intervals in the transporting direction. Each time a positioning mark is detected, a timer circuit begins measuring the time that has passed since the last detection of a positioning mark. If the measured time reaches a predetermined jam detection time, an alarm or a warning display is given, and the recording material stops being transported.
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