| 摘要 |
PROBLEM TO BE SOLVED: To prevent soiling caused by an ion having a polarity opposite to that of toner and to obtain high image quality over a long period by providing an electrode for applying an electric field in the direction of separating the ion having the polarity opposite that of a toner grain, from the surface of a developing means, in a position facing it. SOLUTION: A power source E1 is connected to an electric field applying electrode 15 and a DC voltage or an AC voltage on which a direct current is superimposed is applied to the electric field applying electrode 15 from the power source E1 . The electric field in the direction of separating a negative ion stuck to the surface of a developing device 4 therefrom is applied by the electric field applying electrode 15 provided in the passage region of the surface of the developing device 4 up to the position of a scraping device 9, after the surface of the developing device 4 passes through a developing region D. Thus, the negative ion is concentrated in a solvent scraped by the scraping device 9 and a large number of negative ions are scraped together with the solvent. Consequently, the number of the negative ions on the surface of the developing device 4 after passing through the scraping device 9 is reduced. |
