| 摘要 |
PURPOSE:To stabilize an image by using two kinds of toner which differ in developing performance, and supplying only the toner with high developing performance when the toner concentration in a developer becomes larger than a preset range or only the toner with low developing performance when the toner concentration becomes smaller than the preset range. CONSTITUTION:A reflection concentration detecting means for reflection concentration on an image carrier, a toner concentration detecting means for the toner concentration in the developer, and two kinds of toner which differ in developing performance are used. Normally, the two kinds of toner are supplied at the same time according to a development quantity detected by the reflection concentration detecting means, only the toner with the high developing performance is supplied when the toner concentration in the developer become larger than the preset range, and only the toner with the low developing performance is supplied when the toner concentration becomes smaller than the preset range. Consequently, excessive toner is prevented from scattering in drying operation and carriers are prevented from sticking at high humidity. |
