Developing device, process cartridge, and image forming apparatus

A developing device comprising:

• a developer bearing member that bears a developer on a surface thereof;
• a supplying member that contacts the surface of the developer bearing member and supplies the developer to the surface of the developer bearing member;
• and
• a regulating member that contacts the surface of the developer bearing member and regulates the developer borne on the surface of the developer bearing member, wherein
• the developer includes a toner having a toner particle and an inorganic particle present on a surface of the toner particle;
• a fixing ratio of the inorganic particle to the surface of the toner particle is 80% or more;
• an aspect ratio of the toner is 0.90 or more;
• wherein a contact pressure of the regulating member against the surface of the developer bearing member is denoted by N (gf/mm) and a contact pressure of the supplying member against the surface of the developer bearing member is denoted by D (gf/mm), the following expressions are satisfied:
• D+2×N−6≥0,
• 1.5≤N≤4.0, and
• 2.0≤D≤3.5.