| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which eliminates uneven toner concentration in a two-component developer without increasing the size of the apparatus and incurring steep rise in the cost thereof. <P>SOLUTION: A developing unit supplies toner to developer conveyed in a circulated manner in the developing unit from a predetermined supply position by driving a toner supply member driven by driving force from one driving source 71. The toner concentration in the developer that is passing a predetermined detection position located upstream of the supply position in a circulation direction is detected by a toner concentration sensor 10Y, and on the basis of the result of the detection, prediction data showing the changes in the toner concentration in the developer over time when the developer passes a specified position located downstream of the supply position in the circulation direction and upstream of a developer feed position to a developing roll is calculated. One driving source is controlled based on the prediction data, and supply control is performed so as to eliminate changes in the toner concentration in the developer that is passing the specified position over time. <P>COPYRIGHT: (C)2009,JPO&INPIT |
