| 摘要 |
PURPOSE: To provide a digital image forming device capable of obtaining an appropriate image forming condition corresponding to environmental change by estimating the toner adhesive amount of an image carrier in accordance with the ratio of circumferential speed based on the bias voltage of the surface of a developer feeding carrier and the surface potential of an image display area on the image carrier. CONSTITUTION: A detecting sensor 9 is constituted of a photodiode an phototransistor which are set at the angle of 40 deg. to a photoreceptor drum 1, and receives reflected light in accordance with toner amount forming a color patch image. When the toner does not adhere to the drum 1, a detection signal becomes maximum. Until the drum 1 is covered with the toner, the detection signal becomes low as the toner adhesive amount is increased. A control part 8 sets the circumferential speed ratio of a developing sleeve to the drum 1, inputs the detection signal from the detecting sensor 9, and estimates relation between the circumferential speed ratio and the toner sticking amount so as to set the circumferential speed ratio at the time of forming a digital image. |
