| 摘要 |
PURPOSE:To supply a developer stably at all times and prevent beforehand the deterioration or the like of a development performance and an image quality by controlling an image formation means on the basis of a signal from a development means inside developer deterioration detecting means. CONSTITUTION:A toner supply quantity is controlled on the basis of toner density detected by means of a toner density sensor S1, and toner density at a development counter 22 is made to be fixed at all times. If a toner quantity supplied, that is, a consumption value is small, it follows that the development counter 22 inside toner has stayed in the counter 22 and the stirring time has become long and the toner has deteriorated. In this instance, a toner deterioration detecting means outputs a deterioration signal to a toner deterioration preventing means. And the deterioration preventing means conducts beltlike latent image formation and toner image formation at the non-image portion of a photosensitive body drum 20. This toner image is transported onto a transfer material without being transferred, and removed from on the drum 20 by means of a cleaning means, resulting in the abandonment of deteriorated toner that has stayed in the counter 22. Moreover, timing driving the deterioration preventing means, that is, the formation of a beltlike latent image and a toner image at the non-image portion is conducted on every each color toner right after image formation based on an image signal. |
