| 摘要 |
PURPOSE:To prevent uneven copying, by forming a feedback loop between a charger and the surface of a photosensitive drum for use in a copying machine, etc. in order to control the surface potential itself of the drum. CONSTITUTION:When drum 1 is rotated with motor 5, conductor 4 fixed to drum 1 and the surface of drum 1 are alternately connected electrostatically with induction electrode 2 by connection capacity 3. At that time, a synchronous signal is produced from synchronous signal generator 6, and fed to phase synchronism detector 7, which detects the surface potentials of drum 1 and conductor 4 produced on electrode 2 on the basis of the synchronous signal, and judges height of the 2 potentials. When the potential of drum 1, and that of conductor 4 given from reference voltage source 10 are different, that difference is taken out as the output of detector 7, its rectified output is fed from rectifier 8 to charger 9, thus permitting the surface potential difference between drum 1 and conductor 4 to disappear as drum 1 rotates, and the surface potential of drum 1 to be locked to the constant voltage of source 10. |
