An image forming unit forms an electrostatic latent image on an image carrier based on image data converted by a conversion unit, and the image is developed by a developing portion using toner. A replenishment control unit controls an amount of the toner with which the developing portion is replenished based on a toner density in the developing portion so that the toner density in the developing portion reaches a target density. A first determination unit determines a target density based on a result of a first measurement image being measured. A correction unit corrects conversion conditions based on a result of measuring a second measurement image and a correction condition. A second determination unit determines the correction condition based on the target density determined by the first determination unit.