Patent ID: 7860419

Claim:
A roller temperature control method of an image forming apparatus having a printing process portion that forms a toner image on recording paper, a fixing apparatus that is provided with a hot roller heater that heats a hot roller and a pressure roller heater that heats a pressure roller and that fixes the toner image on the recording paper by sandwiching the recording paper between the hot roller and the pressure roller while heating the hot roller and the pressure roller, and an external heating apparatus that can be moved so as to come in contact with or move away from a surface of the hot roller and that heats the surface of the hot roller when in contact with the hot roller, the roller temperature control method comprising: a temperature detection step of detecting a temperature of at least one of the hot roller and the pressure roller, and a heating control step of controlling heating of the hot roller and the pressure roller based on the temperature detected in the temperature detection step, wherein details of the heating control of the hot roller and of the pressure roller in the heating control step are changed according to an operation state, a standby state, and an installation environment of the image forming apparatus, and when the image forming apparatus is in the standby state and the installation environment is a low-temperature and low-humidity environment, controlling power distribution to the respective heaters with priority in the order of the hot roller heater and then the pressure roller heater, separating the external heating apparatus from the surface of the hot roller, and interrupting power distribution to the external heating apparatus.