| 摘要 |
PURPOSE:To improve the repetitive stability of the charging potential of a photoreceptor by providing a development bias voltage applying device, etc. and charging development bias voltage to be erased according the number of already copied sheets. CONSTITUTION:The time required for obtaining one sheet of copy is let t0. At the time when the development bias voltage upon elapsing of nt0 from the start of copying operation is given by Vn and the development bias voltage application in the next cycle is to be done, the end of one sheet of copying is detected and the number of already copied sheets is counted with a counter unit 1, the results whereof are then inputted to a central processing unit 4. The central processing unit 4 calculates the development bias voltage Vn+1 necessary for the next copying based on the results of measurement having been inputted. From the results of this calculation, the internal resistance in the power source in a development bias voltage applying device 6 is changed over to change the applied voltage to the developing electrode. In this way the change, etc. of the charging characteristics of the photoreceptor are compensated and the repetitive stability of the charging potentials may be improved. |
