| 摘要 |
PURPOSE:To make image density proper by altering the condition of development when the image density drops or rises although the concentration of toner is kept at almost a prescribed value. CONSTITUTION:When the reflection density (image density) of a standard toner image measured by an optical image density measuring means 61 drops/rises below/above a prescribed level, although the concentration of toner is kept at almost the prescribed value, a second CPU 60 controls a developing bias circuit 62 to alter a developing bias. Thereby, a sticking force between the sleeve 20c and the two-component developer, that is, a force by which toner in the two-component developer is moved to a photosensitive drum 1, is altered to make the image density proper. |
