| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of obtaining stable image density, even if the frequency of an image quality priority mode is high, while avoiding shortening of the lifetime and generation of noise, due to an ejection screw 94 being made to rotate at an excessively high speed. <P>SOLUTION: The image forming apparatus includes a developing device 4, having an overflow opening 94 by which, if the level of developer in any of storage chambers (7, 9, and 10) increases due to supply of a premix agent from a supply device (not shown), some of developer is conveyed from the storage chamber to an excessive agent receiving chamber 2 adjacent to it; and the ejecting screw 2a disposed in the excessive agent receiving chamber 2. The image forming apparatus switches operating mode to a speed priority mode of high speed, a standard mode of medium speed, or the image quality priority mode of low speed. The image forming apparatus performs a non-writing ejection process, in which based on the result of the cumulative count of the executing times of the image quality priority mode, the ejecting screw 2a is driven, while the process of writing on the photoreceptor 1 by the optical writing unit is stopped. <P>COPYRIGHT: (C)2009,JPO&INPIT |
