| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus always performing accurate density control without being influenced by unevenness in cycle regarding a developing roller. <P>SOLUTION: After a first patch pattern group is formed, a second patch pattern group is formed under the same condition shifting the timing by 1/2 cycle of the rotating cycle. Then, when the measured values for the measured first and second patch pattern groups are averaged, a measured value excluding the density unevenness can be obtained. When both a density detection sensor and a registration sensor are provided, the density control can be performed in measuring time close to the conventional time if patch pattern groups (for Dhalf) with shifted timing are formed on both edges since the two sensors can be used. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
