| 摘要 |
PURPOSE:To realize such exposure control that the photoreceptor surface potential of an exposure part is kept at a desired level without being influenced by the existence of a toner layer. CONSTITUTION:Since the part of the monitor layer 12 of a photoreceptor 10 is not provided with the coating of a photoconductive layer, it keeps potential zero. After the development of the first color is performed and the photoreceptor 10 is uniformly electrostatically charged in order to form the toner layer of the second color in a state where toner is stuck to an electrostatic latent image part and the part of the layer 12, the exposure of the second color is performed. In such a case, a light quantity transmitted through the toner layer formed on the monitor layer 12 is detected by a photosensor 20. A control means controls the light quantity based on a difference between the light quantity detected at this time and the light quantity detected previously in a state where the toner image does not exist so that the light quantity reaching the surface of the photoreceptor 10 may be the desired light quantity. Then, an image area is exposed with the exposure after control. The exposure of the third color is performed in the same manner. |
