| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with a developing device which can easily redress the balance between a bias formed between a developing roller and a photoreceptor and a bias formed between the developing roller and a magnetic roller and excellently forms a toner thin layer on the developing roller, so as to excellently recover the toner of the developing roller, thereby improving developability with respect to the photoreceptor and suppressing image defects such as the image irregularities of a low tone image. <P>SOLUTION: The respective duty ratios D1 and D2 of a first AC bias used for development, between the developing roller 2 and the photoreceptor 3 and a second AC bias forming the toner thin layer 6 onto the developing roller 2, between the developing roller 2 and the magnetic roller 1 satisfy the relation of D1>100-D2. Further, the frequency f2 of the second AC bias is made higher than the frequency f1 of the first AC bias. <P>COPYRIGHT: (C)2009,JPO&INPIT |
