| 摘要 |
PURPOSE:To form an electric field which is approximately uniform in the thickness direction of a toner layer, by setting an angle formed between surfaces facing the toner layer to be electrified of two electrodes, which triboelectrify a toner, to the angle<180 deg.. CONSTITUTION:The first electrode 5 is formed to a wedge shape to make the angle, which is formed between the surface facing the developing roll 2 of the electrode 5 and that of the second electrode 6, smaller than 180 deg.. Consequently, the distance between surfaces 5b and 6b facing the toner layer of electrodes 5 and 6 is shortened to increase the density of lines of the electric force in the formed peripheral electric field, and lines of the electric force are projected in the direction of a developing roll. Thus, lines of the electric force having high density are formed up to the surface of the developing roll 2 to form the electric field which is approximately uniform in the thickness direction of the toner layer, and the toner is prevented from being deficiently triboelectrified or being not electrified. |
