| 摘要 |
PURPOSE:To prevent an omission of an image and a density drop, etc., and to contrive the improvement of the picture quality by placing a first toner and a second toner at the opposite side to each other on a triboelectrification series against a second developing carrier. CONSTITUTION:Between an electrostatic latent image potential 21 of a red part R and a background potential 22, a developing bias 24 is set, and in a first developing device 5, the development is executed by using a red toner. Subsequently, after this first development has been ended, a second electrifier 15 does not operate and a positive exposure is executed by a second exposing part 20, and a second electrostatic latent image corresponding to a black part B is formed. This latent image is developed by using a black toner of a negative electrification by a second developing device 6. In this case, the developing bias potential 25 is set between the electrostatic latent image potential 21 of the red part and the electrostatic latent image potential 26 of the black part. In this case, it does not occur that the red toner is brought to a polarity inversion from the positive polarity to the negative polarity, and the mixture of the toner is not generated. In such a way, toner images of two colors are formed on a photosensitive body 1, and these toner images are transferred to a recording form 12 at a stretch. In such a way, a density drop of a recording image, etc., are not generated, and color recording of high speed and a high picture quality can be realized.
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