| 摘要 |
<P>PROBLEM TO BE SOLVED: To satisfactorily control toner concentration in spite of the deterioration in carrier associated with the usage of a developing device and the individual difference of a toner concentration sensor in a two-component developing type image forming apparatus. <P>SOLUTION: The image forming apparatus is equipped with: a magnetic permeability detection type toner concentration sensor; a control part capable of changing input control voltage given to the sensor; a drive time acquiring part to acquire cumulative drive time from starting to use the developing device; an absolute humidity acquiring part to acquire absolute humidity; and a storage part. The storage part stores relation between the cumulative drive time and the input control voltage given to the sensor concerning a plurality of absolute humidities respectively. In initialization, a correction value ΔV is obtained from a difference value between initial input control voltage at which the sensor actually shows prescribed voltage and the input control voltage at the absolute humidity in initialization in the relation stored in the storage part. When forming an image, the correction value ΔV is applied to the relation stored in the storage part, and then the input control voltage obtained from the cumulative drive time and the absolute humidity at such a point of time is imparted to the toner concentration sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT |
