A color erasing apparatus is known which is capable of erasing the color of the image on a sheet. A sheet subjected to a color erasing processing by a color erasing apparatus can be repeatedly used in a procedure of forming an image with a color erasable material and erasing the color of the image formed on the sheet.
In the case where an image is formed by an electrophotographic type image forming apparatus, a color erasable material is used as a color erasable toner. The color erasable toner image on a sheet is heated to a temperature higher than the fixing temperature of the toner image, that is, a color erasing temperature, to be color-erased by a color erasing section (heating section). However, even if the color of the color erasable toner image is erased, toner resin is still retained on the sheet as it is.
Thus, toner resin is laminated on a sheet in sequence due to the repeated images formation based on a color erasable toner and the repeated color erasing of coloring toner images. As a result, the laminated toner resin layer gets thicker with the increase of the reuse times of the sheet.
The increase in the thickness of the toner resin layer on a reusable sheet may lead to insufficient heating for a toner image when the color of the coloring toner image is heated and erased by a color erasing section.