Charging apparatus employing charging particles, and image forming apparatus employing such a charging apparatus

An image forming apparatus comprising:

• an image bearing member;
• a charging device for electrically charging said image bearing member, said charging device including charging particles including electroconductive particles having particle diameters in the range of 10 nm-10 μm;
• and
• a charging particles carrying member, forming a nip with the image bearing member, for carrying said charging particles to the nip,
• wherein said charging particles have resistances in the range of 10−1-1012 Ω·cm,
• wherein (an amount per unit area of said charging particles carried by said charging particles carrying member)/(an average roughness Ra of a surface of said charging particles carrying member) is in the range of 0.005-1 mg/cm2/μm.

An image forming apparatus comprising:

• an image bearing member;
• a charging device for electrically charging said image bearing member, said charging device including charging particles including electroconductive particles having particle diameters in the range of 10 nm-10 μm;
• a charging particles carrying member, forming a nip with said image bearing member, for carrying said charging particles to the nip;
• and
• developing means for developing an electrostatic image formed on said image bearing member with a one-component developer including a non-magnetic toner, wherein said developing means contains therein said developer and said charging particles, and wherein said charging particles are supplied from said developing means to said image bearing member, and wherein said charging particles carried on said image bearing member are supplied to said charging particles carrying member,
• wherein the developer remaining on said image bearing member is carried on said charging particles carrying member, and then is transferred from said charging particles carrying member to said image bearing member,
• wherein said developing means is capable of collecting developer remaining on said image bearing member,
• wherein said charging particles have resistances in the range of 10−1 to 1012 Ω·cm;
• wherein (an amount, per unit area, of said charging particles carried by said charging particles carrying member)/(an average roughness Ra of a surface of said charging particles carrying member) is in the range of 0.005-1 mg/cm2/μm, and
• wherein a coating ratio Rc, which is a ratio of said charging particles covering said charging particles carrying member, satisfies the following condition:
• 1≧Rc≧0.2.