Image forming apparatus

A color image forming apparatus comprising

• (a) a photoreceptor comprising an endless transparent support with first and second sides and having thereon on said first side, a transparent conductive layer, a charge carrier generation layer and a charge carrier transport layer in this order;
• (b) a first charger for charging an outermost surface of the photoreceptor;
• (c) a first exposing means for exposing the photoreceptor to light from the second side of the support to form a first electrostatic latent image on the outermost surface of the photoreceptor charged by the first charger;
• (d) a first developing means for developing the first electrostatic latent image to form a first color toner image;
• (e) a second charger for charging the outermost surface of the photoreceptor;
• (f) a second exposing means for exposing the photoreceptor to light from the second side of the support to form a second electrostatic latent image on the outermost surface of the photoreceptor charged by the second charger;
• (g) a second developing means for developing the second electrostatic latent image to form a second color toner image;
• (h) a transfer means for transferring the first and second color toner images together onto a transfer material;
• and
• (i) a fixing means for fixing the toner images transferred onto the transfer material to form a color image;
• wherein a transmittance of said charge carrier generation layer is 20% or less with respect to each of the exposing lights emitted from the first and second exposing means and a carrier drift mobility of said charge carrier transport layer is 1.times.10.sup.-6 cm.sup.2 /V.sec or more under an electric field intensity of 2.times.10.sup.5 V/cm.