| 摘要 |
PROBLEM TO BE SOLVED: To perform image forming which is stabilized for the change or the like of toner electrifying quantity caused by an environmental change and a change in the lapse of time or the like without having a defective image by controlling developing contrast potential and the peak electric field of an AC component or the like so as to be within a specified range based on the detected result of a very small leak current. SOLUTION: An image reading part 10, a light beam scanning part 20 and a light beam pulse width modulation circuit 30 or the like are provided on the upper side of an image carrier 1. Also, an electrifier 2, a rotary type developing device 3, a transfer drum 4, a cleaning device 5 and a discharging lamp 6 are provided in the periphery of the image carrier 1. By this constitution, developing contrast Vs that is a potential difference between the DC component Vbias of developing bias potential and the potential VI of the exposing part of an electrostatic latent image is set in an area where developing toner quantity is made in a saturated state for the increase of the developing contrast Vs. Thus, though the toner electrifying quantity is fluctuated by the environmental change, only an inclination leading to the saturated state is changed and the change in the developing toner quantity is not caused. |
