JP2006243288A5 - - Google Patents

Claims (10)

An image forming apparatus having a fixing device that fixes a developer transferred onto a recording medium by pressure heating.
The fixing device;
A plurality of temperature detection means corresponding to the heating variable region of the heating member;
An image forming apparatus comprising: a protection unit configured to stop the operation of the fixing device by an operation stop signal generated based on detected temperatures of the plurality of temperature detection units.   The fixing device is an induction heating type fixing device including a heating member made of a ferromagnetic material and an exciting coil, and further includes partial heating control means for controlling a partial temperature increase of the heating member. The image forming apparatus according to claim 1. A fixing device that fixes a developer transferred onto a recording medium by pressure-contact heating,
A plurality of temperature detection means corresponding to the heating variable region of the heating member;
A fixing device comprising: protection means for stopping the operation of the fixing device by an operation stop signal generated based on detected temperatures of the plurality of temperature detecting means. The protective means is
At least one excessive temperature rise detecting means that one of the sensed temperature to output the operation stop signal when it is determined that exceeds the predetermined temperature by the plurality of temperature sensing means,
Compared any two outputs of said plurality of temperature sensing means, characterized in that the temperature difference and at least one of the temperature difference detecting means for outputting the operation stop signal when it is determined to have exceeded a predetermined threshold value The fixing device according to claim 3. The fixing device is an induction heating type comprising a heating member made of a ferromagnetic material and the exciting coil, claims and further comprising a partial heating control means for controlling the partial heating of the heating member Item 4. The fixing device according to Item 3. The partial heating control means comprises a portion shielding material to reduce the magnetic coupling between the heating member and said exciting coil,
The temperature sensing means may be best prepared a first temperature sensing means disposed in temperature control position of the heating member, and a second and third temperature detecting means disposed in an operative position of the partial shielding material The fixing device according to claim 5.   The protective means is
    At least one overtemperature detection means for outputting the operation stop signal when it is determined that one of the temperatures detected by the plurality of temperature detection means exceeds a predetermined temperature;
    Comparing at least two outputs of the plurality of temperature detecting means, and including at least one temperature difference detecting means for outputting the operation stop signal when it is determined that the temperature difference exceeds a predetermined threshold,
    7. The fixing according to claim 6, wherein the input of the temperature difference detection means is one of an output of the first temperature detection means and an output of the second or third temperature detection means. apparatus. Predetermined threshold value of the temperature difference detecting means, a positive constant to be equal to or greater than set temperature difference that may occur, characterized in claims 4 or 7 fixing device according to between the plurality of temperature sensing means . It said protection means, fixing device according to any one of claims 3 to 8, further comprising a retaining means for holding the operation stop signal to the cancellation instruction by the operator. A fixing device control method for controlling a fixing device for fixing a developer transferred on a recording medium by press-contact heating,
A temperature measuring step of measuring the temperature by a plurality of temperature detecting means corresponding to the heating variable region of the heating member;
A partial temperature raising step for controlling the partial temperature rise of the heating member based on the detected temperatures of the plurality of temperature detecting means;
When it is determined that one of the plurality of temperature detection means has exceeded a predetermined temperature, or when it is determined that a temperature difference has exceeded a predetermined threshold by comparing any two outputs of the plurality of temperature detection means And an operation stop step of outputting an operation stop signal of the fixing device.