Patent ID: 9727009
Date: 2017-08-08
CPC Classifications: G03G

Claim:
1. A fixing device comprising: a heat roller configured to heat a conveyed sheet; a first heat generating body provided in the heat roller and configured to generate heat in a vicinity of a center in a length direction of the heat roller; a second heat generating body provided in the heat roller and configured to generate heat in vicinities of both ends in the length direction of the heat roller; a power adjuster configured to apply, in a process of image formation, thinning control to electric energy supplied to the second heat generating body only and not to apply thinning control to electric energy supplied to the first heat generating body; a controller configured to control the power adjuster to adjust a thinning amount of thinning the electric energy, based on a time period of continuously conveying the sheet or sheets; and a temperature measuring unit disposed in a position corresponding to the second heat generating body and configured to measure temperature of the heat roller, wherein the controller determines that a thinning amount of electric power in the thinning control of the power adjuster is larger as a cumulative value of time in which the sheet is continuously conveyed is larger, and the controller stops supplying the second heat generating body with the electric power if the temperature of the heat roller measured by the temperature measuring unit has exceeded a predetermined value.