| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase a recovery ratio of undeveloped toner and suppress a ghost phenomenon, regarding an image forming apparatus introducing a hybrid developing system. <P>SOLUTION: A developing unit 4 includes: a magnetic brush roller 23 (developer carrier) that magnetically holds a developer containing carrier and toner; a developing roller 24 (toner carrier) to which the toner is supplied from the magnetic brush roller 23; and an electrode 27 disposed facing the developing roller 24 in the middle of a path where the surface of the developing roller 24 is moved from a position facing a photoreceptor drum 2 (electrostatic latent image carrier) to a position facing the magnetic brush roller 23. A voltage controlled according to one or more indexes selected out of a potential difference between the developing roller 24 and the magnetic brush roller 23, a printing ratio, and the density of an image formed on an intermediate transfer belt 8 is applied to the electrode 27. <P>COPYRIGHT: (C)2009,JPO&INPIT |
