To get a color image of a chromatic color toner and a frosted image of a black toner part without generating an offset by suppressing the surface coarseness of fixing parts by a sheet of image forming at low temperature.

The toner 5a above the fixing part 5 is heat added and moltened by enclosing the fused part 5 with the fixing roller 1 which is heated by the heating element 2 and the pressure roller 3. Then the fixed part 5 is inherited by the fixing roller 1 after the fixing roller 1 is cooled by the cooling part 4 and the toner 5a above the fixed part 5 is cooled until a softening point or a melting point or less. The face which contacts the toner 5a of the fixing roller 1 can get a color image that has gloss on the toner and a frosted image by the surface coarseness, the difference of the molten coefficient of viscosity of a black toner and a chromatic color toner which is used, and switching the fusing temperature that corresponds the molten coefficient of viscosity of a black toner.