JP2004191966A5 - - Google Patents

Claims (9)

An endless first rotating body;
A second rotator that is pressed against the first rotator, wherein the recording material carrying an image is nipped and conveyed by the press contact portion of the first and second rotators, and
Supplied with electric power, and the temperature rise portion increasing the temperature of the local portion of the first rotating body,
A temperature detecting element for detecting a temperature of a portion different from a portion where the temperature is raised by the temperature raising portion with respect to the rotation direction of the first rotating body;
A control unit for controlling electric power supplied to the temperature raising means;
A power supply voltage detector for detecting a power supply voltage;
Have
Said control means based on the temperature detected by said temperature detecting element, with the feedback control of the power to be supplied to the temperature rise portion, when launching the fixing device, the detected temperature is the target temperature of the temperature detecting element A fixing device that temporarily controls the power supplied to the temperature riser based on detection by the power supply voltage detection unit in the vicinity of the timing at which the recording material is reached or in the vicinity of the timing at which the recording material enters the pressure contact portion . The fixing device according to claim 1 , wherein the power supply voltage detection unit detects a power supply voltage based on a temperature increase rate detected by the temperature detection element when energized with a predetermined energization amount . Furthermore, it has the 2nd temperature detection element provided in the said press-contact part vicinity, and the said power supply voltage detection part is the temperature increase rate of the temperature detected by the said 2nd temperature detection element, when it supplies with electricity with predetermined | prescribed energization amount. The fixing device according to claim 1, wherein a power supply voltage is detected based on the power supply voltage . The temperature raising part is provided in the vicinity of the pressure contact part, and includes a heater that generates heat by energization, or a coil that generates an eddy current in the first rotating body by generating a magnetic field by energization . The fixing device according to any one of the above. When starting up the fixing device, temporarily based on the detection by the power supply voltage detection unit in the vicinity of the timing when the temperature detected by the temperature detection element reaches the target temperature or in the vicinity of the timing when the recording material enters the pressure contact portion. The fixing device according to claim 1, further comprising: a nonvolatile memory that stores information relating to electric power supplied to the temperature raising unit . Further, the image forming apparatus includes a determination unit that determines a heat storage state of the fixing device, and the control unit, when starting up the fixing device, near the timing at which the temperature detected by the temperature detection element reaches a target temperature or the recording material. in rush timing near to the pressure contact portion, temporarily, the result of determination by the determination section, and based on the detection result of the power supply voltage detecting unit, according to claim 1 to 5 for controlling the power to be supplied to the temperature rise portion The fixing device according to any one of the above. Furthermore, it has a judgment part which judges the kind of recording material, and when the said control part starts up the said fixing device, the timing detection temperature of the said temperature detection element reaches the target temperature vicinity, or the said press contact part of a recording material in rush timing near to, temporarily, the result of determination by the determination section, and based on the detection result of the power supply voltage detecting unit, one of the claims 1 to 6 for controlling the power to be supplied to the temperature rise portion the fixing device according to either. When the moving speed of the outer periphery of the first rotating body is V, the length from the pressure contact portion to the temperature detection position is a, and the outer peripheral length of the first rotating body is L, the temporary control is performed. The fixing device according to claim 1, wherein the time t to be performed is represented by t ≦ (a + L) / V. 8. An image forming apparatus comprising: an image forming unit for forming an image on a recording material; and a fixing unit for fixing an image on the recording material, wherein the fixing unit is the fixing device according to claim 1.