Patent ID: 7379693

Claim:
A developing apparatus comprising: a rotatable developer carrying member carrying a mono-component magnetic developer to develop an electrostatic image formed on an image bearing member with the mono-component magnetic developer, said developer carrying member being provided with an elastic layer on a surface of said developer carrying member, said developer carrying member being urged against said image bearing member; non-rotary magnetic field generating means provided inside said developer carrying member for magnetically attracting the developer to said developer carrying member; and a developer amount regulating member contacting with said developer carrying member to regulate an amount of the developer carried on said developer carrying member, said developer amount regulating member being provided with an abutting portion provided while abutting in a counter direction to a rotation direction of said developer carrying member, and abutting against said developer carrying member, a step portion provided in a direction away from said abutting portion relative to said developer carrying member, and a separating portion provided upstream of said step portion with respect to the rotation direction of said developer carrying member, wherein when a magnitude of magnetic flux density formed on the surface of said developer carrying member by said magnetic field generating means is defined as B(G), and a component of the magnetic flux density B(G) in a direction perpendicular to the surface of said developer carrying member is defined as Br(G), the surface of said developer carrying member to which said separating portion is opposed includes a position satisfying |Br|/|B|≧0.5.