| 摘要 |
PURPOSE:To eliminate an immobile layer and stabilize an image, and simplify structure and attain remarkable cost reduction by covering the surface of a magnet roll with a sufficient amount of magnetic powder instead of a conventional developing sleeve. CONSTITUTION:Carriers 12 of magnetic powder made of iron oxide or ferrite are attracted on the magnet roll 9 of a developing device 7 and the surface of the roll 9 is covered with the magnetic powder. When high-resistance, single-component toner 13 is supplied from a hopper 8 in this state, the toner 13 is electrostatically charged sufficiently with carriers 12 to make a latent image on a photosensitive body 6 visible. Consequently, even if the high-resistance toner 13 lumps, the problem is solved immediately with carriers 12, so there is no immobile layer formed, thereby obtaining sufficient image density. The conventional developing sleeve is not necessary, so the structure is simplified and remarkable cost reduction is attained. |
