Patent ID: 7844201

Claim:
A color image forming apparatus of a tandem type and a cleaner-less type without a blade cleaner, comprising: a plurality of image carriers on which black and color electrostatic latent images are formed, wherein the electrostatic latent images formed on the image carriers are developed by a non-magnetic single-component developer, a base body of the plurality of image carriers is made of an aluminum substrate, an alumite layer or an intermediate layer is formed on the base body of the image carrier used for the black developer, the alumite layer or the intermediate layer is not formed on the base body of each of the image carriers used for color developers, the resistance per square centimeter of the base body including the alumite layer or the intermediate layer of the image carrier used for the black developer is in a range of 1×10 5 to 1×10 8 Ω on the condition that voltage applied is 100 V, and the resistance per square centimeter of the base body of each of the image carriers used for color developers is 1×10 4 Ω or less on the condition that voltage applied is 100 V.