| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide constitution particularly suitable for such control that the small change of toner concentration is repeated in a two-component developing type image forming apparatus. <P>SOLUTION: The image forming apparatus is equipped with a control part which controls input control voltage given to a magnetic permeability detection type toner concentration sensor, and compares output voltage from the sensor with prescribed reference voltage V<SB>std</SB>to control a supply screw for supplying toner on the basis of a result of detection. The control part changes the input control voltage (arrow A) when the target concentration of the toner in developer is changed to the prescribed amount or more. Meanwhile, the control part does not change the input control voltage but changes the reference voltage V<SB>std</SB>(arrow B) when the change amount of the target concentration is under the prescribed amount. <P>COPYRIGHT: (C)2008,JPO&INPIT |
