An image forming apparatus that can realize an image having adequate image quality, density and color, without provoking excessive consumption of a developer and reduction in productivity. Image formation is performed by forming a latent image on an image carrier based on image information, then developing and transferring the latent image. An image for adjustment on a portion is formed other than a portion on which the latent image is formed on the image carrier. The density of the image for adjustment is detected. Image density is adjusted based on the density of the detected image for adjustment. Image formation control is executed whereby density is adjusted when an image is formed. A printing rate that indicates the percentage of the image formation to a sheet used for image formation is calculated. When the printing rate is determined to be within a set range, the image formation control is executed at a set frequency. On the other hand, when the printing rate is determined to be outside the set range, the set frequency is changed and the image formation control is executed.