Patent ID: 7209690

Claim:
A developing apparatus comprising: a developer carrying member for carrying a developer, the developer carrying member being provided with an elastic layer and adapted to develop, with a developer, an electrostatic image formed on an image bearing member, wherein the developer includes a toner, the toner has a shape factor SF-1 of 100 or more but less than 130, the toner has a storage modulus G′ (140° C.) at 140° C. of 2.0×10 3 dN/m 2 or more but less than 2.0×10 4 dN/m 2 , the toner has a temperature, when the toner has a viscosity of 1.0×10 3 Pa·s in a flow tester temperature elevation method, of 115° C. or more but less than 130° C., and in a surface roughness of the developer carrying member, a center-line mean roughness Ra, a ten-point mean roughness Rz and a mean spacing Sm of irregularities satisfy following relationships (1): 0.06 ≤ Rz / Sm ≤ 0.4 0.8 ≤ Ra ≤ 2.0 ⁢ ⁢ ( μ ⁢ ⁢ m ) } . ( 1 )