| 摘要 |
PURPOSE:To produce a large difference in the quantity of detected light in a photodetector according to the presence or absence of transfer paper by disposing a light emitting element and the photodetector in the specific position with respect to the surface of a photoreceptor. CONSTITUTION:A detector 1 for failure in peeling is disposed near a photoreceptor 2, and has a light emitting diode 3 and a phototransistor 4 in a holder 5. The incident optical axis of the diode 3 to the surface of the photoreceptor 2 and the detection optical axis of the phototransistor 4 intersect at the incident point of the light from the diode 3 onto the surface of the photoreceptor 2 at an optional angle theta1. The holder 5 is fixed in an optional immobile part where the plane inclusive of the incident optical axis of the diode 3 to the surface of the photoreceptor 2 and the detection optical axis of the phototransistor 4 intersects with the plane inclusive of the revolving axis of the photoreceptor 2 and the incident point of the light from the diode 3 to the surface of the photoreceptor 2 at an angle theta2 of inclination on the surface of the photoreceptor 2. |
