The invention provides an image-forming apparatus, having an electrophotographic photoreceptor, a charging unit, a light-exposure unit, a development unit, a transfer unit, and a controller that controls the traveling speed of the peripheral surface of the electrophotographic photoreceptor and that thus makes a period from charging to development variable, wherein: the electrophotographic photoreceptor has an undercoat layer and a photosensitive layer; and the undercoat layer contains metal oxide fine particles with an acceptor compound added thereto; and an image is formed by charging, light exposure, development and transfer while causing the peripheral surface of the electrophotographic photoreceptor to travel in a predetermined direction; and a process cartridge that is detachable from the image forming apparatus.