A light source controller includes a light source driver, a light amount sensor, a memory configured to store property information indicating a relationship between the drive current and the outgoing light amount for each level of the environmental temperature of the solid-state light source, and a controller configured to control the drive current supplied from the light source driver. The image forming member is configured to bear an image. The transitional or injection areas are realized in such a way that they allow the electron transport from the lower energy level of the preceding active area referred to the transport direction into the upper energy level of the following active area referred to the transport direction.