| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for performing accurate toner concentration control by accurate sensor output over a long period of time by preventing fatigue with time caused by the curling habit of an elastic body sheet member cleaning a detection surface of a toner concentration sensor as much as possible. <P>SOLUTION: An image forming apparatus 1 includes a developing unit 14 performing development by a two-component developer, a stirring and conveying member 17 arranged in the developing unit 14 and stirring and conveying the two-component developer, an elastic body sheet 74 fixed to a rotation shaft 71 of the stirring and conveying member 17 and rotated, a toner concentration detection sensor 62 arranged in the developing unit 14 in such a state that a detection surface 67 is exposed, configured so that the detection surface 67 is rubbed by the elastic body sheet 74 and outputting a constant-period small-amplitude toner concentration detection signal 78 detecting toner concentration at a higher value during rubbing and detecting the toner concentration at a lower value after rubbing, and a controller 40 calculating such a timing that an output Min value 78b for detecting the toner concentration at the lower value in the constant-period small-amplitude toner concentration detection signal 78 appears and performing control so as to stop a developing device 9 at the timing. <P>COPYRIGHT: (C)2012,JPO&INPIT |
