| 摘要 |
PROBLEM TO BE SOLVED: To prevent failure in proper toner-concentration-control which occurs because time to switch conditions for the formation of a toner attachment pattern and so on are not stable due to the way in which the device is used. SOLUTION: Image density control is exerted according to the value of a ratio between the result of detection obtained by an optical sensor 10 for a toner attachment pattern formed on an image non-formation area on an image carrier 1 and the result of detection obtained by an optical sensor 10 for a base part on the image carrier 1. In the case, a means 33 is provided for altering a toner concentration control level by 10-100% increasing a target value for the value of the ratio according to the time required to drive for development. |
