| 摘要 |
PROBLEM TO BE SOLVED: To expand a range in which the amount of adhesion of a body that prevents light existing on an object to be irradiated for regularly reflecting light from being reflected regularly can be detected with improved sensitivity as compared with before. SOLUTION: A P sensor 30 receives, with a light-receiving element 32, regular reflection light when incident light from a light-emitting element 31 is regularly reflected on the surface of a photoreceptor drum, and detects the amount of toner adhesion on the photoreceptor drum. The P sensor is composed so that the angle between the center line of an incident light path immediately before the incident light from the light-emitting element reaches the surface of the photoreceptor drum, and the center line of a regular reflection light path immediately after reflection by the photoreceptor drum becomes 25°or smaller. Thus, the area of the photoreceptor drum surface section that does not contribute to the regular reflection light received by the light-receiving element can be brought fully closer to the area of the photoreceptor drum surface section that the toner adhering on the photoreceptor drum surface actually occupies. Therefore, even if the amount of toner adhesion is large, it can be detected at a sufficient sensitivity. COPYRIGHT: (C)2011,JPO&INPIT |
