| 摘要 |
PURPOSE:To obviate a scraping plate, to prevent a carrying means from being deteriorated, to suppress the instability or unevenness of developing powder removal and to attain stable operation for a long period by removing developing powder from the surface of the carrying means by blowing out or sucking fluid. CONSTITUTION:When a pulley 5A is rotated by a driving source, a magnetic belt 4 attracts and sticks developing powder in a guide body 8 by magnetic force, and when the belt 4 is traveled in an arrow Q direction, a magnetic image part of a recording body 20 is developed and visualized by the magnetic powder 1 adhering to the belt 4 contacted with an arc part of the pulley 5A. Since a pump 12 is also driven in accordance with the rotation of the pulley 5A, fluid such as air is brown out from a nozzle 10 and the developing powder 1 used for development is removed from the surface of the belt 4 and returned into a box 2. Since the reduction of toner concentration is detected as the increment of inductance of a coil 3, inductance rise >=a prescribed value is detected by a control circuit 15, and a valve 17 is opened to feed toner. Consequently, the toner concentration can be controlled within a proper range. |
