Image forming apparatus with increased development efficiency and control method

An image forming apparatus comprising:

• a photosensitive member;
• an exposure unit configured to expose the photosensitive member based on image data to form an electrostatic latent image on the photosensitive member;
• a developing unit comprising a developing sleeve, a containing unit configured to contain a two-component developer including a toner and a carrier, and a supply unit configured to supply a bias to the developing sleeve in order that the developing sleeve carries the two-component developer contained in the containing unit, wherein the developing unit is configured to develop the electrostatic latent image using the toner carried by the developing sleeve to form an image;
• a detection unit configured to detect a density of a density detection image formed by the exposure unit and the developing unit;
• a prediction unit configured to predict a toner charge amount in the two-component developer;
• a correction unit configured to correct the toner charge amount of the two-component developer contained in the containing unit based on the density of the density detection image detected by the detection unit;
• a determination unit configured to determine an amount of exposure light by the exposure unit based on the toner charge amount corrected by the correction unit;
• and
• a control unit configured to control a predetermined bias supplied to the developing sleeve for forming the density detection image,
• wherein the predetermined bias is higher than a bias supplied to the developing sleeve for forming the image, and
• wherein the predetermined bias is a bias which is not used for forming the image.