Developer carrier, developing device using the developer carrier, and process cartridge using the developer carrier

A developing device which comprises:

• a developer container that receives a developer;
• and a developer carrier that carries the developer in a thin layer form, which is received in the developer container;
• wherein:
• the device feeds the developer carried on the developer carrier to a developing area that faces an electrostatic latent image-bearing member, and visualizes an electrostatic latent image retained on the electrostatic latent image-bearing member by developing the electrostatic latent image with the developer which have been fed to the developing area,
• the developer carrier comprises at least a substrate and a resin coating layer formed on a surface of the substrate, and
• the resin coating layer comprises at least graphitized particles (i) with a degree of graphitization p(002) of 0.20 to 0.95 and an indentation hardness HUT [68] of 15 to 60 or graphitized particles (ii) with a degree of graphitization p(002) of 0.20 to 0.95 and an average circularity SF-1, which is an average value of circularity obtained by the following expression (1), of 0.64 or more.
• Circularity=(4×A)/{(ML)2×π} (1)
• [In the expression, ML represents the maximum length of Pythagorean theorem of a particle projected image, and A represents an area of the particle projected image.]

A process cartridge which integrally comprises at least (I) an electrostatic latent image-bearing member for retaining an electrostatic latent image and (II) developing means for forming the electrostatic latent image into a developed image with a developer in a developing area, the process cartridge is detachably attached to a main body of an image forming apparatus, wherein:

• the developing means comprises a developer container that receives the developer;
• and a developer carrier that carries the developer in a thin layer form on a surface thereof, which is received in the developer container;
• the developer carrier feeds the developer to the developing area;
• the developer carrier comprises at least a substrate and a resin coating layer formed on a surface of the substrate;
• and
• the resin coating layer contains at least graphitized particles (i) with a degree of graphitization p(002) of 0.20 to 0.95 and an indentation hardness HUT [68] of 15 to 60 or graphitized particles (ii) with a degree of graphitization p(002) of 0.20 to 0.95 and an average circularity SF-1, which is an average value of circularity obtained by the following expression (1), of 0.64 or more.
• Circularity=(4×A)/{(ML)2×π} (1)
• [In the expression, ML represents the maximum length of Pythagorean theorem of a particle projected image, and A represents an area of the particle projected image.]