| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a developing device in an image forming apparatus, wherein residual toner on a development roller is recovered by means of a recovery roller, for preventing toner on the development roller from being recovered by a simple structure when high-density image formation is carried out and maintaining stable image density for realizing stable image quality over the long term. <P>SOLUTION: The developing device in an image forming apparatus is provided with a recovery roller magnetic pole turning means constructed so that a magnetic pole in the recovery roller can be turned to a residual toner recovery position and a non-recovery position around a recovery roller shaft. The recovery roller magnetic pole turning means calculates a developer quantity used for electrostatic latent image development as a printing rate in a formed image. When the printing rate is not more than a predetermined value (when it is not high-density image formation), the recovery roller magnetic pole turning means turns the magnetic pole arranged in the recovery roller to the residual toner recovery position. When the printing rate is higher than the predetermined value (in high-density image formation), the recovery roller magnetic pole turning means turns the magnetic pole to the non-recovery position. <P>COPYRIGHT: (C)2009,JPO&INPIT |
