Patent ID: 8606166

Claim:
A fixing device comprising a conveyance portion for conveying a recording medium; a light source for irradiating an unfixed toner image formed on the recording medium conveyed by the conveyance portion; and a light output control portion for controlling light output from the light source, that melts a toner of the toner image by light from the light source to fix the toner image to the recording medium, wherein when a conveyance speed of the recording medium is p (mm/sec), a length of a light irradiation area on the recording medium in a conveyance direction of the recording medium is q (mm), time during which the toner of the unfixed image is exposed to light while it is conveyed is r (sec) (r=q/p), and energy that is given to the toner of the unfixed image per unit area is J (J=light output per unit area (W/mm 2 )×time r (sec)), the light output control portion controls the light output of the light source so that the energy during a constant time r 1 (sec) from the start of the time r is differentiated from the energy during time r 2 (sec) until the end of the time r after the elapse of the r 1 (r 2 =r−r 1 ), wherein the light output control portion that controls the light output of the light source by a current value and light-emission duty, causes the light source to continuously emit light with 100% light-emission duty at a constant current value during the time r 1 , and causes the light source to intermittently emit light by making the light-emission duty less than 100% at the same current value as that in the r 1 during the time r 2 .