Image forming apparatus and image forming method

An image forming apparatus, comprising:

• a photosensitive drum;
• a developing roller configured to develop an electrostatic latent image on the photosensitive drum with toner to form a toner image;
• a belt onto which the toner image formed on the photosensitive drum is to be transferred or on which a recording material, onto which the toner image is to be transferred, is borne;
• a detector configured to emit light to a detection image formed on the belt and receive reflected light from the detection image;
• an exposure unit configured to form an electrostatic image on the photosensitive drum by exposing a surface of the photosensitive drum at a predetermined exposure amount and by forming a light-part potential from a dark-part potential on the photosensitive drum;
• a high-voltage power supply configured to apply a developing voltage to the developing roller;
• and
• a controller configured to perform a first detection image actual measurement for obtaining a first characteristic indicating a relationship between input image data in a first mode and a density corresponding to the input image data based on a detection result of the reflected light by the detector in the first mode in which a first development contrast is formed between the developing voltage applied to the developing roller and the light-part potential formed on the photosensitive drum,
• wherein the detector is configured to emit the light to the detection image formed on the belt and receive the reflected light from the detection image in a second mode in which a second development contrast is formed between the developing voltage applied to the developing roller and the light-part potential formed on the photosensitive drum and is greater than the first development contrast, and in which image formation is performed with a color gamut different from a color gamut in the first mode, and
• wherein the controller is configured to perform a second detection image actual measurement for obtaining a second characteristic indicating a relationship between the input image data in the second mode and the density corresponding to the input image data based on the detection result of the reflected light.