| 摘要 |
PURPOSE:To prevent effectively the mixing of colors in the 2nd development by using a two-component developer of a carrier having a relatively low resistance in a two-color copying system, and applying a developing bias in such a way that the potential of the 1st latent image is fully embedded with the 1st toner. CONSTITUTION:A latent image of the information in the 1st color is made by an exposing device 13 on a photoreceptor 11, and the reversal development with a developer of the toner of the 1st color and a carrier is performed by the 1st developing device 14. A developing bias is applied on the device 14. The bias may be 40-70% of the surface potential of the photoreceptor. The resistance of the carrier is <=10<7>OMEGA.cm. The resistance is required to be relatively low in order for the developing bias to act effectively. The content of the two-component toner is usually 1-5wt% and the content of the carrier is 99-95wt%. Since the 1st toner is stuck until the potential of the 1st latent image is fully embedded therewith, the mixing of colors in the stage of the 2nd development is prevented and the sharp two-color printing is finally made possible. |
