Image forming apparatus and image forming method

An image forming apparatus comprising:

• an image bearing member;
• a charging device configured to charge a surface of the image bearing member;
• an exposure device configured to expose the surface of the image bearing member to light;
• a potential measurement device configured to measure a surface potential of an electrostatic latent image that is formed on the surface of the image bearing member by the charging device and the exposure device;
• a developing device configured to develop the electrostatic latent image;
• and
• an image forming control unit configured to control image forming conditions,
• wherein the image forming control unit determines an error correction value corresponding to a charge state of the electrostatic latent image on the basis of relationships between charge states of the electrostatic latent image and error correction values which have been prepared in advance, computes an error corrected potential measurement value using the determined error correction value and a potential measurement value measured by the potential measurement device, and controls at least one of the charging device, the exposure device, and the developing device on the basis of the computed error corrected potential measurement value, and
• wherein the charge states of the electrostatic latent image include:
• (i) a charge state of a first latent image that has been charged by the charging device and then reached a measurement area of the potential measurement device without being exposed to light by the exposure device, (ii) a charge state of a second latent image that has been charged by the charging device, been exposed to light by the exposure device, and then reached the measurement area of the potential measurement device, and (iii) a charge state of a third latent image in which a charge density is lower than a charge density in the charge state of the first latent image and is higher than a charge density in the charge state of the second latent image.