| 摘要 |
PURPOSE:To reduce roundabout incidence of light on a light-receiving element and contrive to stabilize an ink donor film (IDF) trailing end detection output, by providing a light-emitting element and the light-receiving element so that their optical axes are parallel to each other. CONSTITUTION:At timings t1 and t2, although a surface (a) not provided with trailing end mark is located beneath a mark reading sensor 6, an output exceeding a reference voltage V0 of a comparator is detected due to specular reflection by the IDF 1 or the like. In the trailing end detecting circuit wherein the light- emitting element 40 and the light-receiving element 50 both of which are highly directional are so provided that their optical axes are parallel to each other, a detection output from the element 5 does not exceed the reference voltage V0 although it is increased at the timings t1 and t2. Accordingly, the level of an output e0 from the comparator becomes high only at timing t3 when a surface (b) provided with a trailing end mark is located beneath the sensor 6, so that the trailing end of the IDF 1 can be detected accurately and securely. In addition, the roundabout incidence of light on the element 50 due to specular reflection can be reduced by slanting the optical axes against the feeding direction of the IDF 1.
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