| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device and an image forming method which enables precisely stabilizing picture concentration over a wide range of concentration. SOLUTION: By executing high concentration side adjusting processing (Step S3), the optimum contrast potential is determined and, thereafter, the optimum electrifying bias and the optimum developing bias are determined by executing low concentration side adjusting processing (Step S5). That is, the adjustment of concentration is performed in the two steps. In addition, before the low concentration side adjusting processing (Step S5), the relative relation between electrifying bias and developing bias for maintaining the optimum contrast voltage is set in accordance with the attenuation characteristic of surface voltage of a photoreceptor 21. Further, in the low concentration side adjusting processing (Step S5), the developing bias is changed according to the relative relation while the electrifying bias is changed and, thus, the second patch picture is formed. |
