Charging member and electrophotographic imaging apparatuses employing the same

A cartridge for an electrophotographic imaging apparatus, the cartridge comprising:

• an electrophotographic photoconductor;
• a charging member contacting the electrophotographic photoconductor to charge the electrophotographic photoconductor;
• a developing unit to develop an electrostatic latent image to a visible image;
• and
• a cleaning unit to clean a surface of the electrophotographic photoconductor,
• wherein the charging member comprises:
• a conductive support;
• a conductive elastic body layer on the conductive support;
• and
• a surface layer on the conductive elastic body layer,
• wherein the surface layer includes a binder resin, first particles, and second particles, the first and second particles being dispersed in the binder resin, the first particles including acrylic resin particles having an average particle diameter of about 16 μm to about 35 μm, and the second particles including spherical silica particles having an average particle diameter of about 3 μm to about 10 μm,
• wherein an amount of the first particles in the binder resin is in a range of about 5 parts by weight to about 20 parts by weight, based on 100 parts by weight of the binder resin, and
• wherein, when a mass of the first particles is M1 and a mass of the second particles M2, the condition of 0.2≤M1/(M1+M2)≤0.8 is satisfied.

An electrophotographic imaging apparatus comprising:

• an electrophotographic photoconductor;
• a charging member contacting the electrophotographic photoconductor to charge the electrophotographic photoconductor;
• an exposure unit to form an electrostatic latent image on a surface of the electrophotographic photoconductor;
• a developing unit to develop the electrostatic latent image to a visible image;
• a transfer unit to transfer the visible image onto an image receiving member;
• and
• a cleaning unit to clean a surface of the electrophotographic photoconductor,
• wherein the charging member comprises:
• a conductive support;
• a conductive elastic body layer on the conductive support;
• and
• a surface layer on the conductive elastic body layer,
• wherein the surface layer includes a binder resin, first particles, and
• second particles, the first and second particles being dispersed in the binder resin, the first particles including acrylic resin particles having an average particle diameter of about 16 μm to about 35 μm, and the second particles including spherical silica particles having an average particle diameter of about 3 μm to about 10 μm,
• wherein an amount of the first particles in the binder resin is in a range of about 5 parts by weight to about 20 parts by weight, based on 100 parts by weight of the binder resin, and
• wherein, when a mass of the first particles is M1 and a mass of the second particles M2, the condition of 0.2≤M1(M1+M223 0.8 is satisfied.