| 摘要 |
PURPOSE: To keep the quantity of toner supplied to a photoreceptor constant and to enable stable printing without a change in printing quality by controlling the interval between a developing magnetic roll and the photoreceptor with a controller. CONSTITUTION: Screw jacks 20 are provided in four places in total of the front and the rear and both sides in the lower part of a developing device 5, suitable motors 21 are provided in the screw jacks 20 respectively, in such a manner that the motors are connected to the controller 10. In a conventional manner, the gap G between the developing magnetic roll 11 and the photoreceptor 2 is constant, even if a printing speed is changed, but in this method, the screw jacks 20 provided in the lower part of the developing unit 5 are rotated by the motors 21 connected to the controller 10, to enable the automatic adjustment of the height of the developing device 5. Therefore, the gap G between the developing magnetic roll 11 and the photoreceptor 2 is changed in accordance with the switching of the printing speed, in the same way as the photoreceptor 2, an exposing device 4, a paper running device 8 and a fixing device 9, as well. |
