| 摘要 |
1529350 Electrostatic separation of particles EASTMAN KODAK CO 22 Dec 1975 [2 Jan 1975] 52345/75 Heading B2J [Also in Division G2] Apparatus for classifying a dry electrographic developer which comprises particles of a porous carrier and particles of toner with a charge control agent of first polarity, the apparatus comprising spaced parallel upper and lower electrodes a potential source for applying a potential between the electrodes, the upper electrode being of opposite polarity to the first polarity, means for repeatedly passing developer between the electrodes whereby the larger toner particles are attracted to the upper electrode and means for removing the attracted particles from the electrode. As shown, carrier and toner particles are mixed in trough 29, then carried by trays 33 into hopper 37 and chute 39 to pass between the 2 electrodes, the lower electrode 11 being a metal sheet and is ground and the upper electrode 21 being of foraminous metal and is charged to attract the larger toner particles. The remaining developer falls into trough 29 and is recycled until required size distribution is obtained. Toner particles on electrode 21 are removed by suction or by placing a dielectric sheet thereon which is periodically changed. Additional toner may be added to trough 29 if required. |
