| 摘要 |
A system for the delivery of a substantially uniform mono-layer of toner to an electrostatic latent image in an imaging member (such as a rotating cylinder) insures proper handling of the toner, and utilizes first and second rollers which function as a polarity filter for toner, allowing only particular charged toner to be transferred from a toner reservoir to the imaging member. The twin roller delivery system (30) comprises first (31) and second rollers (33) mounted for rotation about substantially parallel substantially horizontal axes, so that the peripheral surface of the first roller receives the toner from the substantially open top reservoir (13), and the second roller receives toner from the first roller and transfers it to the imaging member (10). The first and second rollers are charged to different electrical potentials, e.g. both being positive with the second roller at a potential that is about 400 volts below the first. The rollers are rotated in opposite directions about the axes of rotation. Toner scraping (34, 35) is provided at specific points along the first and second rollers so that any residual toner falls into the toner reservoir, and a suction system (50, 60) is provided adjacent the second roller both before and after its peripheral surface transfers toner to the imaging member, to remove stray toner without disturbing the substantially uniform mono-layer of toner.
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