| 摘要 |
<P>PROBLEM TO BE SOLVED: To stably form a toner image of satisfactory image quality by restraining the effect of a variation in the density of a patch image which is caused by the factor of changes in the structure of an apparatus. <P>SOLUTION: To make a DC development bias Vavg optimum, the patch image Ivan which has a length L1 longer than the length L0 of the circumference of of a photoreceptor is formed. Then, the toner density of the patch image Ivn is found from the average of a sensor output obtained by sampling the length L0 of them. As a result, a value corresponding to the average ODavg of optical density OD can be found. This prevents the patch image from being affected by a variation in density which occurs in accordance with the rotation period of the photoreceptor, making it possible to accurately obtaining the optimum value of the DC development bias Vavg. <P>COPYRIGHT: (C)2004,JPO |
