| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain an excellent image without density unevenness and a ghost by adopting such a constitution that the value of the magnetization of magnetic carriers with a specific magnetic flux density satisfies a specific conditional expression, with respect to the maximal value of a magnetic flux density on the surface of a developer carrier, of a formed magnetic field. SOLUTION: The magnetic field is formed all over the upstream side in the rotational direction of a developing sleeve 21 from the proximity part of it and a regulating sleeve part 22, in such a manner that the magnetic pole N1 of a permanent magnet 30 in the developing sleeve 21 cooperates with the magnetic pole S1 of the magnet 31 in the regulating sleeve 22, so that a developer regulating region G for regulating a developer is formed by the magnetic field all over the upstream side. The developing device uses such a carrier that the value [emu/cm<3> ) of the magnetization σ1000 of the magnetic carrier with a magnetic flux density of 1000 [Oe] satisfies a conditional expression of σ1000 <350, σ1000 <=-0.5B+600 and σ1000 >=12500B<-3/4> , with respect to the fact that the magnetic flux density B of the magnetic pole N1 of the magnet 30 in the developing sleeve 21 is 700 [Oe]. |
