| 摘要 |
PURPOSE:To charge toner stably all the time by setting the specific resistance of the roll type surface layer of a regulating member which regulates the developer layer thickness on a developing roll surface to 10<-2>-10<3>OMEGA.cm. CONSTITUTION:The specific resistance of the conductive skin layer 17C of the regulating member 17 which is provided rotatably in press contact with the developing roll 15 and regulates the layer thickness of the one-component nonmagnetic developer 14 on the surface of the roll 15 is set to 10<-2>-10<3>OMEGA.cm. When the specific resistance is <=10<-2>OMEGA.cm, the cost is increased extremely and when >=10<3>OMEGA.cm, the charge injection into the toner is insufficient. A bias is applied from a bias power source 18 to the regulating member 17 to regulate the developer layer thickness on the surface of the roll 15 according to the press contact force and relative speed difference of the regulating member 17, but the specific resistance is set within the said range, so the amount of toner charging has almost no variation even numbers of copies are taken and the toner is charged stably. |
