Patent ID: 7650104

Claim:
A developing apparatus comprising: a developer carrying member that carries a mono-component developer; and a developer regulating member that abuts on the developer carrying member to regulate a thickness of a layer of the developer carried by the developer carrying member, wherein, surface roughness parameters of a surface of the developer carrying member satisfy the following equations (1) and (2), 3.0≦Rpk≦9.0 (1) 2≦Pc2≦10 (where, count level=average particle diameter of developer (μm)/2, evaluation length=1 mm) (2), and at least at an abutment portion between the developer carrying member and the developer regulating member, surface roughness parameters of a surface of the developer regulating member satisfy the following equations (3) and (4), 0.030≦Sm≦0.170 (3) 0.10 ≦Rvk ×(100 −Mr 2)/100≦1.30 (4), where, Sm is a mean spacing of profile irregularities [mm] specified in JIS-B0601-1994; Rpk is an initial wear height [μm] specified in DIN 4776; Rvk is an oil retaining depth [μm] specified in DIN 4776; Mr 2 is a profile bearing length ratio 2 [%] specified in DIN 4776; and Pc 2 is a parameter measured by a Contact Surface Roughness Measuring Instrument SE3500 (manufactured by Kosaka Laboratory Ltd.), and denotes a number of profile peaks having a height larger than a count level (arbitrarily variable) from a center line per the evaluation length of 1 mm on a roughness curve.