| 摘要 |
An electrostatic image developer dispenser (10, 310) forms a uniformly thick and uniformly charged layer of developer particles on a transport surface (106) of a conveyor (50, 350) for delivering particles from a reservoir (22) to a development region (107) adjacent to a photoreceptor (100). A magnet bar assembly (70, 370) inside the tubular conveyor (50, 350) attracts particles to the transport surface (106) for conveyance to the development region (107). A magnetic doctor blade (110, 410) presents a surface (114, 414) parallel to the transport surface (106) to establish a regulating gap (116) between the doctor blade surface (114, 414) and the transport surface (106). The doctor blade (110, 410) extends in the transport direction (67) from opposite one pole (91, 393) of the magnet bar assembly (70, 370) toward an opposite pole (85, 387) downstream from the one pole (91, 393), to concentrate and orient the magnetic field in the particle layer formation area. As such, the doctor blade (110, 410) has a first induced magnetic pole at its periphery (114, 417) opposite from the first magnetic pole (91, 393) of the magnet bar assembly (70, 370) which is of an opposite polarity from the first magnetic pole (91, 393), and the doctor blade (110, 410) has a second induced magnetic pole at its periphery (419) closest to the second magnetic pole (85, 387) of the magnetic bar assembly (70, 370) which is of an induced polarity opposite from the polarity of its first induced magnetic pole. In one embodiment, the magnet bar assembly (70, 370) has a pole plate (90) opposite from the doctor blade surface (114) and angularly offset therefrom in a direction opposite to the transport direction (67). In another embodiment, the magnet bar assembly (370) has two pairs of opposed magnets (382, 389). A scraper blade (152) bears against the transport surface (106) to remove developer particles from the transport surface (106) after they have passed through the development region (107). A cleaning blade (126) is provided in the dispenser (10, 310) that bears against the photoreceptor (100) to remove developer particles therefrom upstream from the development region (107) and recycle the removed particles back into the reservoir (22). |
