1. An image forming apparatus comprising: an image forming unit that forms an image on a continuous recording medium by transferring to the continuous recording medium a toner image obtained by developing a latent image formed on a photoreceptor; and a controller that controls the image forming unit such that an image based on image information is formed in a specific image area on the continuous recording medium, and at the same time, a specific image pattern is formed in a specific side area outside the image area on the continuous recording medium, wherein an amount of toner used as the specific image pattern formed in the specific side area is determined by an amount of toner used as the image formed in the specific image area, and a size of the specific image pattern formed in the specific side area outside the image area is controlled based on an area coverage amount of the image formed in the specific image area.