An image forming system includes an image forming unit which forms an image as a toner image on a printing medium, a first fixing unit which fixes, on the printing medium, the toner image formed by the image forming unit, a second fixing unit arranged at a position different from the first fixing unit and used when a larger amount of heat is necessary for fixing the toner image on the printing medium, and a changing unit which changes the sequence of image formation by the image forming unit when the second fixing unit is used during image formation.
展开▼