Image forming apparatus having a positively charged single layer type electrophotographic photoreceptor

An image forming apparatus, comprising:

• a positively-charged single layer type electrophotographic photoreceptor;
• a charging device that has a contact charging member for charging a surface of the photoreceptor;
• an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image on the surface of the photoreceptor;
• a developing device for developing the electrostatic latent image into a toner image;
• and
• a transfer device for transferring the toner image from the photoreceptor to a transferred body,
• wherein the positively-charged single layer type electrophotographic photoreceptor has a conductive substrate and a photosensitive layer,
• the photosensitive layer contains a charge generating agent, a charge transport agent and a binder resin together, the binder resin having a yield point strain of 9 to 29%,
• the contact charging member is a charging roller that has a conductive layer with a thickness of 1 mm to 3 mm, and
• the binder resin is a polycarbonate resin having a viscosity-average molecular weight of 55,000 to 75,000 and a recurring unit expressed by one of the formulae (15) to (17):
• wherein the number “50” in the formula (17) indicates that the binder resin of the formula (17) is copolymerized at a copolymerization ratio of 50%.