Patent ID: 7298995
Filing Date: 2007-11-20
Classification: G03G

Abstract:
1. A developing device comprising: stirring-transfer means which transfers a developing agent while stirring it; a magnetic roller comprising a magnetic sleeve and a plurality of magnetic poles disposed along the circumferential direction within said magnetic sleeve for transferring said developing agent while holding it on the surface of said magnetic sleeve; and a developing roller disposed to oppose said magnetic roller at a predetermined space therefrom for attracting a toner included in the developing agent held on said magnetic roller so as to deposit electrostatically thereon, that are disposed in a housing which contains a two-component developing agent comprising a magnetic carrier and a non-magnetic toner, wherein said non-magnetic toner has a volumetric mean particle size in a range from 6 to 11 μm, and proportion of toner particles not larger than 4 μm is 8% by number or less, and said magnetic carrier has saturation magnetization in a range from 35 to 50 emu/g and volumetric mean particle size in a range from 35 to 50 μm.