Patent ID: 7218881

Claim:
A developing apparatus comprising: a first developing member and a second developing member disposed in succession from an upstream side to a downstream side with respect to a rotation direction of an image bearing member on which an electrostatic image is formed and in opposed relationship with said image bearing member; and applying means for applying a developing bias comprising a DC voltage and an AC voltage superimposed one upon the other to said first developing member and said second developing member, wherein the developing bias is applied to said first developing member and said second developing member and the electrostatic image is developed with a developer including a toner and a carrier, and the toner on the image bearing member is collected, and wherein when a closest distance between said first developing member and the image bearing member is defined as SD 1 (m), and a closest distance between said second developing member and the image bearing member is defined as SD 2 (m), and a peak-to-peak voltage of the developing bias applied to said first developing member is defined as V 1 (V), and a peak-to-peak voltage of the developing bias applied to said second developing member is defined as V 2 (v), and a volume resistivity of the carrier is defined as 1.0×10 x (Ω·cm), V 1/ SD 1− V 2/ SD 2≦(0.65 x− 4.5)×10 6 (V/m), 1.2×10 6 ≦V 1/ SD 1≦(0.35 x+ 3.5)×10 6 (V/m), (0.30 x− 1.5)×10 6 ≦V 2/ SD 2≦9.0×10 6 (V/m), and 9.0≦X≦13.0 are satisfied.