Patent ID: 6879800

Claim:
A developing apparatus comprising: a developing roller having a fixed magnet having at least two magnetic poles different in polarity and a sleeve roller placed rotatably on the outer periphery of the magnet; and a developer regulation member being opposed to the developing roller between the two magnetic poles different in polarity, said developing apparatus for transporting a dual-component developer to a developing section for developing with rotation of the sleeve roller, wherein a position where the developer regulation member is opposed to the developing roller is in an area wherein the magnetic flux density in the tangent line direction becomes 95% or less of the maximum value upstream in the developer transport direction from the position at which the magnetic flux density in the normal direction formed by the two magnetic poles on the sleeve roller surface of the developing roller becomes 0 gausses and is in an area wherein the magnetic flux density in the normal direction becomes 90% or less of the maximum value of the upstream pole in the developer transport direction.