摘要 |
After forming solid patch images under various patch generating conditions (E, Vb), the optical densities of the respective patch images are measured by a patch sensor, and patch generating conditions matching with a higher-density side target density (OD=1.2) are extracted as "higher-density side correlation data." Further, line patch images are formed under various patch generating conditions (E, Vb), the optical densities of the respective line patch images are measured by the patch sensor, and patch generating conditions matching with a lower-density side target density (OD=0.2) are extracted as "lower-density side correlation data." An optimal exposure energy and an optimal developing bias are set based on one piece of correlation data (E2, Vb(3)) belonging to said product set of the higher-density side correlation data and the lower-density side correlation data.
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