Patent ID: 7894736
Filing Date: 2011-02-22
Classification: G03G

Abstract:
1. An image forming apparatus which forms a toner image on an image carrier, transfers the toner image to a long recording medium longer than a regular size, and fixes the toner image transferred to the long recording medium by a fixing device, the fixing device comprising: a fixing member; a pressure member pressure-contacted with the fixing member thereby forming a nip between the fixing member and the pressure member; a first temperature detecting device for detecting a temperature of the fixing member; a second temperature detecting device for detecting a temperature of the pressure member; a heater for heating the fixing member, wherein the heater includes: a remaining amount detecting device that detects a remaining amount of electric power supplied from the auxiliary power source; a calculating device that calculates the amount of accumulated heat of the fixing member and the pressure member from the temperature of the fixing member and the pressure member detected by the first and second temperature detecting devices; a recording medium length calculating device that calculates a recording medium length at which fixation of the toner image onto the long recording medium can be assured, from the remaining amount of electric power supplied from the auxiliary power source, which is detected by the remaining amount detecting means, and the amount of accumulated heat; a comparing device that compares the length of the long recording medium that is used in print operation when a print instruction is input, with the recording medium length at which fixation of the toner image at this time point can be assured; and a control device that starts the print operation only when the recording medium length at which fixation of the toner image can be assured is equal to or greater than the length of the long recording medium that is used in the print operation.