| 摘要 |
PURPOSE:To prevent a color toner image from being destroyed without spoiling characteristics of a two-component developer even when one-component magnetic toner is mixed by using the magnetic toner of the one-component developer as the carrier of the two-component developer of a following developing device. CONSTITUTION:A photosensitive drum 1 is charged electrostatically by an electrifier charger 2 uniformly to a specific potential VSO. Negative exposure corresponding to the 1st color information is performed by an exposing means 3 to attenuate the potential of the exposed part to a specific potential VK1. Its latent image is developed by a developing device 4 with the one-component developer made of, for example, black magnetic toner by impressing a developing bias potential VB1. At this time, the potential of the black toner image is Vt1. Then, the photosensitive body is recharged electrostatically by a reelectrifier 5 and a developer consisting of red nonmagnetic toner and the same magnetic toner with the developing device 4 as a magnetic toner is used for development after negative exposure. Consequently, characteristics of the two-component developer are not spoiled even when the one-component magnetic toner is mixed, and a color toner image is prevented from being destroyed. |
