| 摘要 |
PURPOSE:To obtain an image of good quality by making an image density stable by controlling a developing bias voltage at the time of developing a reference image density pattern so that it is varied according to the variation of a dark part potential arising with a regulating correction control of a light part potential. CONSTITUTION:When a correcting control is carried out to regulate the light part potential VL, the dark part potential VD rises to make an over corrected condition, and a pattern latent image potential of the reference image density pattern also rises in the same manner. Therefore, the developing bias voltage is variably controlled according to the over corrected condition of the pattern latent image potential of the reference image density pattern, which is the dark part potential VD, keeping a developing potential, formed between the pattern latent image potential of the reference image density pattern and the developing bias potential constant. Thus, a detecting pattern for a toner supply ing control can be always developed at the same density, making constant the density of the image formation, achieving a good quality image. |
