| 摘要 |
PURPOSE:To detect the abnormality of a toner sensor by detecting the fluctuation of a detected toner concentration value outputted from the toner sensor. CONSTITUTION:The detected toner concentration datum from the toner sensor 64 is sampled by a CPU 76 in a cycle asynchronous with the rotating cycle of 1st and 2nd stirring rollers 58 and 60 stirring the toner in a developing device 26, and the sampled datum is stored in a 1st storage part 78, and the previous datum is stored in a 2nd storage part 80. By accessing and comparing the respective data in the 1st and the 2nd storage parts 78 and 80, whether or not a change exists between the respective data is judged. Such judgement is performed to every inputted datum. In the case no change is continuously found between the datum of this time and the datum of the previous time by specified number of times previously set, a controller 72 outputs a control signal so that specified driving control may be performed by judging that the abnormality occurs in the toner sensor 64. |
