| US 7,349,642 B2 | ||
| Image heating apparatus including PID control | ||
| Hideki Tatematsu, Ashiya (Japan); Masahiro Samei, Toyonaka (Japan); Tomoyuki Noguchi, Kasuga (Japan); and Shigemitsu Tani, Hirakata (Japan) | ||
| Assigned to Matsushita Electric Industrial Co., Ltd., Osaka (Japan) | ||
| Filed on Mar. 08, 2005, as Appl. No. 11/73,717. | ||
| Claims priority of application No. 2004-068033 (JP), filed on Mar. 10, 2004. | ||
| Prior Publication US 2005/0201768 A1, Sep. 15, 2005 | ||
| Int. Cl. G03G 15/20 (2006.01) | ||
| U.S. Cl. 399—69 | 5 Claims |
| 1. An image heating apparatus comprising:
an image heater that heats an unfixed image on a recording medium;
a heat generator that induction-heats said image heater;
a temperature detector that detects a temperature of said image heater; and
a power controller that controls power supplied to said heat generator by PID control based on the temperature detected by
said temperature detector so that the temperature of said image heater is maintained at an image fixing temperature appropriate
for heating and fixing of said unfixed image to the recording medium,
wherein said power controller changes the control value of said PID control according to the temperature at a start of heating
of said image heater detected by said temperature detector,
wherein said PID control relates to a deviation between the temperature detected by the temperature detector and a target
temperature of the image heater, and is controlled by a combination of a value of elements proportional to said deviation,
a value of elements proportional to an integral of said deviation and a value of elements proportional to a derivative of
said deviation,
wherein said power controller changes a proportionality factor of the deviation, said integral of the deviation and said derivative
of the deviation in accordance with the temperature at the start of heating of said image heater, whereby said power controller
changes the control value of said PID control.
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