| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing the occurrence of an image defect such as fogging or density irregularity by positively collecting deteriorated toner and keeping a toner state on a developing roller excellent. <P>SOLUTION: The image forming apparatus refreshes toner on the developing roller 2 by forcibly consuming the toner on the developing roller 2 by development processing in a forcible toner consumption mode. In the forcible toner consumption mode, AC bias to be applied to the developing roller 2 is changed to enhance the intensity of electric field in a developing area. For example, the peak-to-peak voltage Vpp or the frequency (f) of the AC bias is made high. Then, good-quality toner out of the toner flicked out from the developing area adheres to a photoreceptor drum 11 again by the electric field. Meanwhile, the deteriorated toner hardly reacts to the electric field, and gets on air flow generated by the rotation of the developing roller 2 and forms laminar flow on the downstream side of the developing area in the rotating direction of the developing roller 2. A toner collecting mechanism 8 is arranged in a laminar flow path. <P>COPYRIGHT: (C)2009,JPO&INPIT |
