In the past papers, we had proposed a new model of the charge generation process in a single layer organic photoconductor, supposing indirect process of charge generation. In this study, we expanded this concept into more general dual layered system. Photoreceptors comprising a charge generation layer (CGL) of bisazo pigments dispersion into polyvinyl-butyral resin and a charge transport layer (CTL) of solid solution of donor molecule into polycarbonate resin were employed in the experiment. The change of electrophotographic characteristics by thickness of CGL in both conventional dual layer system and plus charging inversed dual layer system suggested the location of charge generation site at the interface of CGL and CTL and the energy diffusion from the bulk CGL. The estimated energy diffusion length was much longer than those ever reported as exiton diffusion. It was also found that whole discussion derived in the previous study upon single layer OPC was applicable to this dual layer system.