| 摘要 |
PURPOSE:To prevent the variance of the intensity of a stopping electric field and clogging of an aperture due to sticking of a charged toner to obtain always good pictures, by applying an AC voltage across the first and the second conductive layers of a screen photoreceptor to generate an AC nonuniform electric field between the first and the second conductive layers on the inside of the aperture. CONSTITUTION:When an AC power source 8 is connected to the first and the second conductive layers 2 and 4 to apply the AC voltage, the AC nonuniform electric field is generated between end faces of the first and the second conductive layers 2 and 4 in an aperture 6. Charged toner particles are accelerated and moved from their generating device, namely their supply source and are oscillated between points B and C along lines A of electric force of the AC nonuniform electric field, and an outward centrifugal force orthogonal to lines A of electric force acts upon them in every half cycle of this oscillation, and an average centrifugal force Fd acts as an average. Further, toner particles 7 are repulsed strongly at the point B in the direction of the electric field by conductive layers 2 and are attracted weakly to conductive layers at the point C, and as the result, toner particles 7 receive an average repulsive force Fg, which acts in the direction of the weaker electric field, in directions of tangents of lines A of electric force on the average. As the result, an average repulsive force Fr acts as the resultant force of forces Fa and Fg. Charged toner particles 7 receive always the force toward the center of the aperture 6 by this average repulsive force Fr and are not stuck to end faces of conductive layers, thus preventing clogging of the aperture. |
