| 摘要 |
PURPOSE:To prevent generation of a negative characteristic and to prevent decrease in density and ground fogging when a frequency decreases by impressing intermittently alternating electric fields between a latent image holding member and a developer holding member so that the final component is formed of the electric field component returning the developer from the former member to the latter member. CONSTITUTION:The developing bias having such a waveform as shown in the figure is impressed to the sleeve of a developing device 4 from a bias power source 15. When the alternating electric fields reversing the developer moving process by intermittent alternating electric fields are intermittently impressed between a developer holding member 10 and a latent image holding member 1, the negative development is remarkably improved under the intermittent alternating electric field which ends in the process of returning the developer from the member 1 to the member 10 side and the fog-free image having an excellent gradation characteristic is obtd. Magnetic particles 9 are stuck to the surface of the member 10 by the magnetic force of a magnetic roller 11 enclosed in the member 10 and are conveyed by the rotation of the member 10 in an arrow direction (b) and are supplied to the member 1. The latent image of the member 1 is thus developed. |
