Method to correct aging of a photoconductor in an image forming apparatus using a potential attenuation map

摘要

Good images are formed without density irregularity even if an image supporting body varies with time. Potentials at developing locations after exposing the surface of an a-Si photoconductive body, which are recorded in a potential attenuation characteristic map, are compared with seven ranges A-G obtained by dividing the surface of the a-Si photoconductive body at every 6-volt interval to detect deviations of the potentials from a prescribed potential Vl (step S2). Individual blocks all over the surface of the a-Si photoconductive body are classified to A-G, and the exposure values are set in accordance with A-G so that Vl of the individual blocks on the surface of the a-Si photoconductive body belongs to D range (step S3). An input image undergoes image processing after its entire plane being divided into blocks corresponding to the surface of the photoconductive body (steps S4 and S5).
The recorded potential alternation characteristic map is compared with a correspondent initial map recorded when the photoconductive body was new.