| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain cost reduction, regarding a developing apparatus for an electrophotographic image forming apparatus, where a thin toner layer is formed on a developing roll from a magnetic brush formed on a magnetic roll, the toner is flew from the developing roll to a photoreceptor and an image is developed, such the developing method is suitably executed in the case of using two-component developer. <P>SOLUTION: Developing biases applied on the magnetic roller 2 and the developing roll 4 are separately constituted of DC+AC. Then, the current alternatively flows in between two rolls 2 and 4, and the toner is activated, then, the toner supply from the magnetic roll 2 to the developing roll 4 and the scraping of the toner from the developing roller 4 to the magnetic roll 2 can be performed with a comparatively low bias voltage. Then, as compared with such the case of applying AC bias only on the developing roll 4, the amplitude of the AC bias is reduced, and an influence on the photoreceptor 6 is avoided, and also, the frequencies of two AC biases are kept constant, and the cost reduction of the AC bias generation circuit 13 is attained. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
