Developing device, and image forming method and process cartridge using the developing device

An image forming method, comprising:

• providing a developing roller facing an image bearing member;
• charging a surface of the image bearing member;
• irradiating the charged surface of the image bearing member to form an electrostatic latent image thereon;
• developing the electrostatic latent image with a toner to form a toner image;
• controlling an amount of a toner adhered to the developing roller, so that an electrostatic latent image formed on the image bearing member is developed with the toner to form a toner image, wherein the following relationships are satisfied:
• 0.08×100.3×Dv<Ra<0.18×100.3×Dv (1)
• 2.0<(Ra/RSm)×100<4.0 (2)
• 8<Rz<15 (3);
• transferring the toner image onto a recording medium;
• and
• fixing the toner image on the recording medium,
• wherein Dv (μm) represents a volume average particle diameter of the toner, Ra (μm) represents an arithmetical mean roughness of the developing roller in a longitudinal direction, Rz (μm) represents a ten-point mean roughness of the developing roller in a longitudinal direction, and RSm (μm) represents a mean length of roughness curve elements of the developing roller.