| 摘要 |
PURPOSE:To obtain a desired illuminance distribution even in an unmagnified mode and a variable power mode when deviation between parts in present by providing plural light sources so as to control a lighting state independently and further providing a correcting device correcting the lighting amount of each light source. CONSTITUTION:In the variable power mode, the duty cycle ratio of a pulse is controlled, whereby the picture quality is improved with a slit shape on a photosensitive drum 11 as a fixed one. Even if the light sources L1-L16 are controlled in the same state, their lighting amounts develop deviation because of the deviation between the parts of the lighting equipment, deviation at assembly, the deterioration of parts in use and the part replacement. Accordingly, variable resistance VR1-VR16 of a lighting amount correcting device 34 are connected to the light sources L1-L16. Then said variable resistances VR1-VR16 are appropriately adjusted in initialization or part replacement, whereby the lighting amount is corrected to obtain the desired illuminance distribution, and the individual control can be made normally. |
