| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device and an image forming apparatus for suppressing the occurrence of image noise such as image irregularity, ghost, and carrier adhesion and reduction of image density. SOLUTION: This developing device comprises a first conveying member having a fixed and arranged magneto roller 58 and a cylindrical sleeve that includes the magnet roller and is supported rotatably on its periphery, and a second conveying member that faces the first conveying member and faces an electrostatic latent image carrier. In the carrier contained in a developer, the volume average particle diameter is 20-50μm, magnetization in a magnetic field of 10<SP>6</SP>/4π(A/m) is 100-300 mWb/m<SP>2</SP>, and specific resistance is 10<SP>12</SP>-10<SP>15</SP>Ωcm. On a cross section S perpendicular to the center axis X of the magnet roller 58 of the first conveying member, the magnetic pole N1 of the magnet roller closest to the second conveying member has two peaks P1 and P2 of magnetic flux density. In the cylinder sleeve rotation direction 80, and the magnetic flux density at the peak P1 on the upstream side is the magnetic flux density at the peak P2 on the downstream side or smaller. The image forming apparatus includes the developing device. COPYRIGHT: (C)2009,JPO&INPIT |
