| 摘要 |
PURPOSE:To obtain a high-quality picture, by detecting the surface potential after the destaticizing process with use of a composite photoreceptor having >=2 sensitive layers and by a copying method requiring the 1st and 2nd electric charging processes (double-color method) and thus controlling the 1st and 2nd charging voltages. CONSTITUTION:The 1st and 2nd chargers 2 and 3 are the positive and negative polarity corona chargers respectively. A lamp and a filter are provided to the charger 2 to perform an exposure of red color simultaneously or immediately after charging. The development is carried out after an image exposure 4 by the 1st developer 10 which stores a black toner of positive polarity and the 2nd developer 11 which stores a display toner of negative polarity. Then the polarity is converted for the red toner through a pre-transcription charger 12, and both the black and red toners are transcribed by a transcription charger 13 of negative polarity. The result of detection of a surface potential detector 15 is supplied to an application voltage controller 16 after the functions of a destaticizer 7, a cleaning device 8 and an etching lamp 9. Thus the application voltage is controlled for the chargers 2 and 3. |
