| 摘要 |
PURPOSE:To effectively correct image quality based on a detected result by directly detecting the condition of the deterioration of developer. CONSTITUTION:A sensor 31 for detecting the degree of the deterioration of the developer consisting of a magnetic permeability sensor is attached to a spot where the pressure of developer is low in a developing device. The sensor 31 is initialized to output a specified reference output value when the toner concentration of the developer is reference toner concentration. A controller 32 compares the output value of the sensor 31 with a reference output value to obtain an output difference, detects the degree of the deterioration of the developer based on the output difference and feedback-controls the light quantity of a copying lamp 4 based on the detected result, so that a copied image is stabilized. |
