| 摘要 |
<P>PROBLEM TO BE SOLVED: To make a concentration control improved in control precision and short in control time. <P>SOLUTION: The improvement of control concentration and the shortening of the control time are made compatible by selectively using first control with high precision of determining image formation conditions based on the concentration of a formed toner image and second control with short control time of determining the image formation conditions based on history of the image formation conditions determined by the first control. The second control is determined so that Cnew=Cm1+(Cm1-Cm2) is established when considering charge bias or development bias determined after nonoperating time equal to or more than a predetermined value this time as Cnew, charge bias or development bias first determined by the first control after the nonoperating time equal to or more than the predetermined value last time as Cm1 and charge bias or development bias first determined by the first control after the nonoperating time equal to or more than the predetermined value in the second from last time. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
