| abstract |
PURPOSE:To obtain images of good quality by constituting a developer of a developing and cleaning device, which is used as a developing device as well as a cleaning device, with two kinds of carrier different in average particle size. CONSTITUTION:A developer D which is stuck onto a developing and cleaning roll 9 and is controlled to a certain layer thickness so as to rub the surface of a photosensitive body in accordance with rotation of the roll 9. This developer D consists of a mixture of magnetic carriers 10 and 11 different in average particle size and a magnetic toner 12. With respect to magnetic carriers, a metal such as iron, nickel, or the like or their oxide or alloy is used as it is, or an insulating resin film is coated on the surface of particles of these materials. |