Patent ID: 7773923

Claim:
A developing apparatus comprising: a developer carrying member which carries a developer, a voltage being applied to the developer carrying member; a developer amount regulating member which regulates the developer on the developer carrying member; and a developer supplying member provided so as to abut the developer carrying member to supply the developer to the developer carrying member, a voltage being applied to the developer supplying member, wherein the developer used has a volume-average particle diameter R that is in a range of 4.0 μm≦R≦6.2 μm, wherein a surface of the developer carrying member has an arithmetic mean roughness Ra (μm) that is not more than 0.10 times the volume-average particle diameter R of the developer, wherein a value which is defined by subtracting the voltage applied to the developer carrying member from the voltage applied to the developer supplying member is of a same polarity as a normal charging polarity of the developer on the developer carrying member after regulation by the developer amount regulating member, wherein a triboelectrification polarity of the developer supplying member with respect to the developer is of the same polarity as the normal charging polarity of the developer, and wherein, in a cross section taken in a direction in which the developer carrying member and the developer supplying member abut each other, an abutment width S in which the developer carrying member and the developer supplying member abut each other is in a range of 2.5 mm≦S≦5.5 mm.