| 摘要 |
PURPOSE:To obtain a developed image which is free from fogging and has a high resolution by executing non-contact two-component development using 1-6mum toner. CONSTITUTION:The developer 4 is formed by mixing magnetic particles M contg. magnetic powder and nonmagnetic particles (toner T) essentially consisting of a resin contg. at least >=70% (by weight) particles having 1-6mum grain size in the resin. The developer 4 is controlled to a suitable thickness by a doctor blade 10 as a sleeve 2 internally having a magnet roller 3 rotates. The developer layer and the drum 1 surface are not in contact with each other in a static state. The toner T in the developer 4 is electristatically charged by the friction with the magnetic particles M and the sleeve 2 and is carried to a developing region. A developing bias is impressed between a back electrode 11 of the photosensitive drum 1 which holds the electrostatic latent image and the sleeve 2 by a DC power source 5 and an AC power source 6 to form alternate electric fields in the developing region by which the electrostatically charged toner is moved back and forth between the sleeve 2 and the drum 1 and the latent image is developed.
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