Patent ID: 8666295

Claim:
An image forming apparatus, comprising: an image bearer configured to bear an image; an irradiator configured to irradiate the image bearer to form an electrostatic latent image thereon; an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image; a transferer comprising an intermediate transfer belt configured to transfer a toner image onto a recording medium; and a fixer configured to fix the toner image on the recording medium, wherein the intermediate transfer belt has a circumferential length not less than 2,000 mm and is driven at a linear speed not less than 350 mm/sec, has an inner circumferential surface having a surface roughness Ra of from 0.2 to 0.4 μm, and comprises a substrate layer and a high-resistivity layer having a resistivity higher than that of the substrate layer, wherein the high-resistivity layer has a surface resistivity higher than that of the substrate layer by 0.3 to 2.5 log Ω/□ in common logarithm value when applied with a voltage of 500 V, and wherein the substrate layer is formed of a polyimide resin comprising a polyimide resin component (S) having an imide bond between 3,3′,4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine and a polyimide resin component (A) having an imide bond between 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenylether in a weight ratio (S/A) of from 0/100 to 40/60.