| 摘要 |
PURPOSE:To easily detect the abnormality of a toner concentration sensor by deciding that a magnetic permeability detecting means is abnormal when a detected magnetic permeability does not regularly pulse in the state that a driving control signal for a driving source is outputted. CONSTITUTION:The replenishment demanding signal Vc from the toner concentration sensor 51, a signal Vg for showing the output pulse state of the sensor 51, a signal Vk for showing the rotating state of a main motor and a signal Vo for showing the rotating state of a screw are inputted in respective input ports P2 - P5 in a CPU. And the driving control signal for the main motor is outputted from an output port P6. In the CPU, a subroutine for abnormality detecting processing is performed, and then, it is decided that the sensor 51 is abnormal in the case that only the signal Vg is at an H level and all the other signals are at an L level. This is because the sensor output does not pulse in spite of the normality of the main motor and the screw roller. And also it is decided that the sensor is abnormal in the case that only the signal Vg is at the L level and the other signals are at the H level. Contrarily, this is because only the sensor output is normal and the others are abnormal. It is easy to decide the abnormality in this way. |
