| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a developing device accurately estimating toner concentration in the developing device regardless of a working environment to supply a required quantity of toner in a suitable timing, and to provide an image forming apparatus including the same. <P>SOLUTION: A developing container 20 is virtually divided into regions R1 to R10, a toner concentration sensor 40 is disposed in the region R3, and toner is consumed in the regions R7-R9. The toner consumption amount in the regions R7-R9 is calculated from the printing rate, and toner for that consumption is supplied to the position where the toner has been consumed by printing based on the driving time of a toner supply motor 27 determined from the calculated toner consumption amount and the drive timing of the toner supply motor 27 determined from the developer circulating time. A sensor output value of a toner concentration sensor 40 is stored continuously for the time taken to make two laps on a circulating passage 2, and a developer circulating time is reset based on the peak interval of the first and second lap sensor output values. <P>COPYRIGHT: (C)2011,JPO&INPIT |
