Fixing device and an image forming apparatus using the same

An image forming apparatus includes an image forming mechanism and a fixing mechanism. The fixing mechanism fixes a visible image formed by the image forming mechanism onto a recording sheet. The fixing mechanism includes a first roller, a second roller, a belt, a third roller, and an applicator. The second roller includes a first heater having a first heat capacity. The belt is looped over the first and second rollers. The third roller is arranged opposite to the first roller via the belt, includes a second heater having a heat capacity smaller than the first heat capacity of the first heater, applies a pressure to the belt and the first roller, and rotates in conjunction with a movement of the first roller via the belt. The applicator is arranged at a position in contact with the third roller and applies oil to a surface of the third roller.