| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrophotographic sensitizing system for improving toner concentration control accuracy, in the case that an image resolution setting is changed, that is, a printing speed setting is changed. SOLUTION: Toner concentration in a mixing area 3 is detected by a magnetic permeability sensor 5 and the concentration is compared with a threshold. When a detection voltage is equal to or below the threshold, a digital voltage Vdig is outputted to a CPU 9. In the case of detecting that the toner runs short based on the Vdig, the toner is supplied by the CPU 9. Besides, an input voltage Vcont applied on the detection voltage is switched by the CPU 9 in accordance with the printing speed, that is, based on printing quality such as image resolution, monochromatic printing and color printing, and the variance of the toner concentration. Then, the linearity of the detection voltage is obtained all over the toner concentration detection extent. Besides, the reduction time of the toner concentration is counted by the CPU 9, and the Vcont is switched, then, the concentration is highly accurately detected so as to correct the concentration to the prescribed one. |
