| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixing device capable of appropriately controlling a temperature without a temperature decrease or overshoot even when continuously passing small-size paper or switching from large-size paper to small-size pape, and an image forming apparatus equipped with the same.SOLUTION: There is provided a fixing device which comprises: a sub-heater 25c having a maximum-heat generating part at the central part; main heaters 25a and 25b having a maximum-heat generating part outside the sub-heater; and temperature detection means 40a, 40b and 40c in which the main heaters and the sub-heater, which start PID temperature control by the sub-heater by turning the main heaters on when warm-up is started or large-size paper is passed and turning the main heaters off when small-size paper is passed, are selectively operated. An initial turn-on ratio at the start of the PID temperature control of the sub-heater is determined in accordance with the difference between the temperature detected by each temperature detection means at the start of the PID temperature control of the sub-heater and the paper-feeding target temperature of a print job. |
