Patent ID: 6259870
Filing Date: 2001-07-10
Classification: G03G

Abstract:
A method of controlling temperature of a heating unit of a fixing device, which shifts from a normal operation mode to a power saving mode after the lapse of a predetermined time without performing a fixing operation during the normal operation mode and restores the normal operation mode upon receipt of a fixing operation request during the power saving mode, to fix a toner image, which is formed on a medium, to the medium as the heating unit heats the toner of the image, said method comprises the steps of:(a) measuring a temperature of the heating unit during the normal operation mode;(b) calculating a first tendency of temperature rise in terms of an amount of temperature rise per unit time when the temperature is controlled so as to rise during the normal operation mode, based on the result of temperature measurement;(c) calculating, based on said first tendency of temperature rise, a lowest temperature of the heating unit during the power saving mode in terms of a temperature such that a duration till the temperature of the heating unit reaches a target fixing temperature enough to melt the toner of the image is a desired period during which the fixing device restores the normal operation mode from the power saving mode; and(d) keeping the temperature of the heating unit not lower than said lowest temperature.