| 摘要 |
PURPOSE:To obtain an optimum toner image, by obtaining a threshold of the toner density control in accordance with the surface potential of a recording body and controlling the toner density in accordance with the result of the comparison between the toner image density and the threshold. CONSTITUTION:A photosensitive drum 1 is charged uniformly throughout by a primary charger 8 and is destaticized by a secondary charger. The light beam which is emitted from a laser 12 and is modulated by an ultrasonic optical modulator 11 is incident to the secondary charger 9, and an image signal is inputted to this modulator 11 from a central controlling circuit 13 in accordance with an image to be recorded, and the image on the photosensitive drum 1 is exposed. A surface potential sensor 14 is arranged before a developer 3, and the surface potential of the photosensitive drum 1 is measured and is inputted to the central controlling circuit 13, and a toner hopper motor driving circuit 15 is controlled on a basis of the surface potential and the density measured value from an image density detecting unit 5 to adjust the quantity of toner supply to the devoloper 3. |
