Image forming apparatus

An image forming apparatus comprising:

• a latent image bearer;
• a charger to charge a surface of the latent image bearer;
• an exposure device to expose the surface of the charged latent image bearer according to image data to form an electrostatic latent image thereon;
• a developing device to supply toner to the electrostatic latent image on the latent image bearer to develop the electrostatic latent image;
• a potential detector to detect a surface potential at a detection position on the surface of the latent image bearer, the detection position disposed between an exposure position and a development position in a direction of rotation of the latent image bearer;
• and
• a potential controller to determine an image forming condition, the potential controller including
• a potential calculator to calculate an exposed area potential based on a detected potential smaller in charging polarity than a potential threshold, out of the surface potential detected by the potential detector, the exposed area potential meaning a surface potential of an exposed area of the latent image bearer;
• and
• a threshold determiner to set the potential threshold to a value between the exposed area potential and an unexposed area potential meaning a surface potential of an unexposed area of the latent image bearer after charging by the charger, based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition under which the image forming apparatus is used.