摘要 |
PURPOSE:To prevent the formation of hysteresis on a developing roll even when a developer having inferior flowability is used and take an invariably excellent copy by applying an alternating voltage to the blade of a regulating member which regulates the thickness of the developer layer on the surface of a developing roll. CONSTITUTION:The developing roller 15 has a blade 17 set in a wiper direction as the regulating member for the formation of the toner layer. When the alternating voltage is applied by an alternating voltage power source 18, an alternating electric field is produced between the blade 17 and developing roll 15 to oscillate the blade 17 finely, so even a developer having inferior flowability has excellent flowing-in characteristics and a toner layer having no hysteresis is formed uniformly on the roll 15 to take an excellent copy without cope density irregularity. |