| 摘要 |
PURPOSE:To prevent mixing of each color toner, by using a one-component type nonmagnetic developer made of a nonmagnetic toner for the first development, and a one-component type magnetic developer made of a magnetic toner for the second development, and carrying out jumping development for each development. CONSTITUTION:The first latent image to be printed with black color having positive potential with respect to an intermediate potential Vs, and the second latent image to be printed with red color having negative potential with respect to the potential Vs are formed on the surface of a photoreceptor 1. This is developed with a developing device 5 and then, with a developing device 6. The developing sleeves of the devices 5, 6 are subjected to a developing bias voltage corresponding to the potential Vs, and a negatively charged nonmagnetic black toner is used for the device 5 and a positively-charged red magnetic toner is used for the device 6. As a result on the surface of the photoreceptor, the black toner is attached to the first latent image with the device 5, and the red toner is attached to the second latent image with the device 6, and no toner is attached to the part having the intermediate potential Vs, thus forming a 2-color print on a transfer paper sheet 9. |
