| 摘要 |
PURPOSE:To hold the surface potential at a development point constant regardless of the quantity of continuous records and to obtain images with constant density by measuring the number of times of continuous electrostatic charging and adding charging correction based upon the measured value to charging current control which is performed by measuring the surface potential at a charging point. CONSTITUTION:The counted value of the quantity of records from the start of recording which is obtained by a continuous record quantity counting device 130 and the surface potential of a photosensitive drum 1 which is detected by a surface potential detecting means 110 are inputted to a supply current control means 120 equipped with a current control circuit 120b and a correction information recording circuit 120a stored previously with potential variation characteristics of each quantity of continuous records of the photosensitive drum 1 which is charged by a charger 2. A control means 120 performs correcting arithmetic on the basis of those input values and supplies the charging current to the charger 2 through a high voltage power source 10 on the basis of the arithmetic result more and more as the quantity of continuous records become larger and larger to increase the surface potential at the charging point, thereby controlling the surface potential at the development point to a constant value even if dark attenuation increases. |
