| 摘要 |
PURPOSE:To automatically and easily detect the life of developer by a simple constitution, and to timely recognize a time of replacing the developer. CONSTITUTION:This detector is provided with an ADC sensor 5 for detecting the concentration of toner on a photosensitive drum 1, a comparator 6 for comparing the output of the ADC sensor 5 with a reference value and a display device 7 for displaying the comparison result, and an allowable level for fogging is set in advance and the photosensitive drum 1 on which an electrostatic latent image is not formed is developed, and then, the toner concentration at this time is detected by the ADC sensor 5 so as to be compared with the allowable level for fogging, and when the detected value of the toner concentration becomes equal to or exceeding the reference value, the warning that the developer is used to the limit of the life is given. |
