| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress degradation in image quality of an obtained image even when continuously forming images that consume less toner. <P>SOLUTION: A control unit 100 includes: a toner concentration/developer amount calculator 103 for calculating the amount of developer and toner concentration in a developing housing; a developer replenishing setting unit 104 for setting, on the basis of the amount of developer and toner concentration, the amount of developer to be newly replenished to the developing housing and the toner concentration of this developer; an image area coverage calculator 105 for calculating the image area coverage of a toner image to be formed from now on; a development potential difference calculator 106 for calculating a development potential difference between a development bias to a developing roll and the exposure potential of a photoreceptor drum; and a developer discharge setting unit 107 for increasing the height of the opening of a developer discharge port provided in the developing housing of a developing unit if the image area coverage is smaller than a reference image area coverage, and the development potential difference is larger than a reference development potential difference, thereby increasing the amount of developer discharged from the developing unit. <P>COPYRIGHT: (C)2011,JPO&INPIT |
