| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a high temperature part which results from heat accumulating in a part that cannot be detected by a fixing temperature sensor. <P>SOLUTION: An image forming apparatus includes: temperature sensors SN 1 and SN 2 that detect the temperature of a fixing nip; a heater control means that controls the heater by turning on or off the heater such that the temperature detected by the temperature sensors SN1 and SN2 during an image recording operation is maintained at a predetermined heat fixing temperature; a duty ratio measurement means for measuring a duty ratio d that is the ratio of the time for which the heater is on to the time for which the heater is controlled by being turned on or off during the image recording operation; a duty ratio threshold storing means C4C for storing a threshold d0 for the duty ratio; and a cooling operation performing means C7 for controlling the operation of the fixing device so that the fixing device is prevented from being overheated when the measured duty ratio d is smaller than the duty ratio d0. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
