| 摘要 |
<p>PURPOSE:To detect the paper winding without an error and omission by a method wherein the light incident angle of an luminant element is made larger than that of the normal on the surface of a sensitizing drum. CONSTITUTION:When the attaching angle of a luminant element 1 is changed so that the incident angle is diagonal to the drum surface, that is, at an angle smaller than 90 deg. to the drum surface, the reflection light strength VD from the luminant element 4 on a sensitizing drum 1 is significantly reduced. On the contrary, the level of the reflection light strength Vp from a sheet of paper 2 wound around the sensitizing drum 1 does not change so much because of irregular reflection due to the fine uneven surface of the paper 2. Therefore, the distance between VD and Vp becomes wider compared to former ones, so that the reference voltage Vr can be set in the middle between VD and Vp with an allowance and an error in detecting paper winding can be satisfactorily prevented.</p> |
