| 摘要 |
PURPOSE: To enable a proper operation of forced supply of a toner without being affected by conditions, of the detected surface by using, as a reference value, a value of the actual detection of an image carrier texture part by an optical density detecting means, which is near in time to an almost the same state as the optical density detection of the image carrier texture part by the optical density detecting mean executed after the toner is supplied to the developing device. CONSTITUTION: A P-sensor 14 has such a characteristic that output becomes smaller as an image density becomes high, the ratio of the output VSG of the P-sensor 14 detected at prescribed timing by using the characteristic to the output value VSGP of the detection of the density of a reference image formed on a photoreceptor 1 in accordance with a prescribed reference pattern is obtained and the quantity of the toner to be supplied is set with the ratio, to supply the toner from a toner hopper 7 to a developing unit 6 by a required quantity. When a toner supplying operation is completed, stirring by a stirring paddle 9 is continued until the value of the output VSG detected after the toner is supplied becomes the same as VSGP in the state where the toner has already an sufficiently been electrified, to electrify the toner. |
