Image forming apparatus with calibrated exposure control

An image forming apparatus which forms an image on a recording medium, comprising:

• an image bearing member;
• a charging device configured to charge uniformly a surface of the image bearing member;
• an exposure device configured to expose the uniformly charged surface of the image bearing member with light modulated according to image data to form a latent image on the surface of the image bearing member;
• a potential detecting device configured to detect a surface potential of the image bearing member on which the latent image is formed;
• a developing device configured to develop the latent image on the image bearing member into a toner image;
• a density detecting device configured to detect a density of the toner image on the image bearing member;
• a storage unit configured to store first data representing a correspondence relationship between a theoretical value of an exposure amount based on image data corresponding to a solid image area in the toner image and an actual exposure amount, second data representing a correspondence relationship between a theoretical value of an exposure amount based on image data corresponding to a line image area in the toner image and an actual exposure amount, and a ratio of an exposure amount of the image bearing member by the exposure device in forming the sold image area and an exposure amount of the image bearing member by the exposure device in forming the line image area;
• and
• a control device configured to control the exposure device,
• wherein the control device is configured to:
• control the exposure device to form a pattern image, which is a solid image, on the image bearing member;
• update the first data based on a detection result of a latent image corresponding to the pattern image detected by the potential detecting device and a density of the pattern image developed by the developing device detected by the density detecting device;
• update the second data based on an updated first data and the ratio;
• and
• control the exposure device based on the updated first data and an updated second data.