An image processing apparatus includes a light emitting unit that emits light, a document reading unit, an image forming unit, a decoloring unit, and a control unit. The document reading unit generates image data from an original document that is irradiated with light from the light emitting unit. The image forming unit forms an image on a sheet based on the image data generated by the document reading unit, wherein the image is formed of a decolorable material that is decolored when heated to a predetermined temperature or higher. The decoloring unit decolors the image on the sheet using heating. The control unit controls a light intensity of the light emitted from the light emitting unit based on a temperature of the decoloring unit.