| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which enables a developing device of a vertical agitation structure to control the height of a developer surface so as to fall within an appropriate range while suppressing an increase in the rotational speed of a developer conveying member. <P>SOLUTION: The developing device includes: a developing sleeve 28; an agitating chamber 24; a developing chamber 23 disposed vertically above the agitating chamber 24; a first conveying screw 26 for conveying developer in the agitating chamber 24 to the developing chamber 23; a second conveying screw 25 for conveying developer in the developing chamber 23, thereby supplying it to the developing sleeve 28; a drive motor M1 for driving the first conveying screw 26; a drive motor M2 for driving the developing sleeve 28; and a correcting means for correcting the height of a developer surface of the developing chamber 23. The correcting means has: a temperature humidity detecting means for detecting the temperature and humidity of the inside of an image forming apparatus; and measuring means for detecting cumulative time for which developer is used. On the basis of information from the temperature humidity detecting means and measuring means, the correcting means controls the driving speed of the first conveying screw 26. <P>COPYRIGHT: (C)2009,JPO&INPIT |
