| 摘要 |
PURPOSE:To obtain a sharp copy image regardless of magnification, i.e. enlargement, unmagnification, and reduction by varying a developing bias to a condition suiting to selected copy magnification associatively with charging in copy magnification. CONSTITUTION:A developer holding member (sleeve) 3 is fitted outside of a shaft body 1 and supported rotatably between side plates of a developer container 4 while part of its circumference is exposed to the outside. A magnetic blade 5 is fitted as a toner layer regulating means to the container 4 with a screw 6 opposite a magnetic pole N1 while facing the sleeve 3 across a gap g1. Consequently, when a reduction copy is taken, a switch S3 is closed with a copy magnification selection button 10c, and when an unmagnified copy is taken, such a developing bias 9c that the supply of toner is reduced is applied; when an enlarged copy is taken, a switch S1 is closed with a button 10a to apply the developing bias 9a so that the supply of toner is increased, thereby obtaining a sharp copy image. |
