| 摘要 |
PURPOSE:To obtain a clear image free of ground fogging by supplying charged magnetic toner to a surface which has an electromagnetic latent imae by a supply roller and magnetic force and by collecting remaining toner by a potential difference in addition to magnetic force. CONSTITUTION:A developing roller 7 and a supply roller 6 are provided which rotate in the same direction with the surface of the photoreceptor 1, turning as shown by an arrow, of a dry type electronic copying machine. The roller 6 and 7 are both made of nonmagnetic materials and have incorporated magnets 8 and 9. A case for toner 3 has a toner exit 5 and an entrance 5'. As development starts, the toner 3 move to the developing roller 7 by the incorporated magnets 8 and 9 and, after being charged by the friction of a coating layer 11, is adsorbed to an electrostatic latent image, thus performing the development. The excessive toner 3 is collected efficiently through the rotations of both the rollers 6 and 7, the magnets 8 and 9, and bias voltages applied from power sources 12 and 13 in cooperation to return to the case 4 through the entrance 5'. Consequently, the tone is supplied adequately to obtain an imae free of ground fogging. |
