| 摘要 |
PURPOSE:To always compensate fixed image density by effectively detecting the deterioration of developer and preventing the image density from lowering according to the detected result. CONSTITUTION:A rotating sleeve 42a is installed on the outer periphery of a magnet 42b for forming a magnetic brush, and the developer is carried to a developing position opposed to the surface of a photosensitive drum 1 by the rotation of the sleeve 42a and restored to a stirring roller 41 by the rotation of the sleeve 42a after development. The developer is formed to the magnetic brush by the magnetic pole N1 of the magnet 42b at the developing position opposed to the drum 1 so as to develop an electrostatic latent image formed on the surface of the drum 1. A conductive plate 44 electrically coming in contact with the developer is installed before the developing position, and a current flowing to the plate 44 is detected by a current detection circuit 9. Based on the detected current quantity, a CPU 5 controls a main electrostatic charging control circuit 3 controlling the potential of the surface of the drum 1 through a main electrostatic charger 2. |
