| 摘要 |
PURPOSE:To obtain a stable image having no uneven concentration by comparing a ratio and a reference level, and controlling a value of a toner replenishing bias, when it is decided to execute toner replenishment. CONSTITUTION:After the development has been ended, the quantity of reflected light of each color is measured by a photosensor 28 placed adjacently on a metallic roller 26 at the time of passing of a pattern image. As for a toner replenishing signal, ON-OFF is determined by an output voltage corresponding to this photosensor 28. In this state, when the toner replenishing signal becomes ON, a replenishing roller 204 turns counterclockwise, and a toner is replenished in the shape of thin layer to the replenishing roller 204 by a replenishing blade 203 from a toner tank 206. Subsequently, it is electrified, supplied to a developing roller 205, and developed to a latent image on a drum. In such a way, a stable image having no uneven concentration in the sub-scanning direction is obtained. |
