| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively restrain the variation of image density by preventing a fogged image caused by excessive supply in performing resetting operation after detecting the abnormality of developer concentration. <P>SOLUTION: In the resetting operation performed after a developer concentration detecting sensor 42 detects an error level showing the variation of the concentration of two-component developer in a developing device 4 at the specified level or more, a temporary target value is set between the error level and a target value. Toner is supplied to the device 4 by a toner supply device 49 until the concentration of the developer in the device 4 detected by the sensor 42 attains the temporary target value, and a test patch is formed with the developer after the toner is supplied. The density of the test patch is detected by an image density detection sensor and fed back to an image-forming condition so that the image density may be a specified value based on the result of detection. <P>COPYRIGHT: (C)2004,JPO |
