| 摘要 |
PURPOSE:To prevent the soil at the rear edge part of a transfer paper with an electrophotography copier that exposes an original to light by means of a moving light source, by increasing the quantity of exposured light for a certain period of time after the rear edge part of the maximum copy size original is exposed to light. CONSTITUTION:A lamp regulator 9 which applies the voltage of a commercial power supply 8 to a lamp 3 is varied in 8 steps by the signals of 8 combinations for example which are delivered from a light quantity control part 10 for the purpose of control of the picture concentration. In addition, a timer IC11 is set outside the part 10 to be triggered by the application of a switch 12. The signal H level is applied to the regulator 9 for a certain time t1 that is decided by a resistance R1 and a capacitor C1. The switch 12 is set near the termination of the path of a mobile optical system to be applied after the exposure of the maximum size original. In such way, the soil caused by the shadow of a frame can be prevented at the rear edge part of the transfer paper. |
