Induction heating fixing device having a central processing unit, and image forming apparatus using the fixing device

An induction heating fixing device used in an image forming apparatus, comprising:

• a first CPU for controlling operation of the overall said image forming apparatus;
• a member to be heated;
• a thermistor, connected to said first CPU, for detecting a temperature of the heated member;
• an excitation coil, arranged in the vicinity of the heated member, for heating the heated member by induction upon receiving a current;
• and
• an induction heating control circuit for controlling current supply to said excitation coil;
• a second CPU for controlling operation of said induction heating control circuit independent of the control of said first CPU;
• and
• wherein said first CPU outputs a heating ON/OFF signal according to the temperature detected by said thermistor, said second CPU controls the operation of said induction heating control circuit on the basis of the heating ON/OFF signal, and said first CPU obtains the temperature of the heated member, detected by said thermistor at the start of current supply to said excitation coil, and supplies a power control signal to said induction heating control circuit to obtain a power supply output on the basis of the detected temperature.

An image forming apparatus comprising:

• a main body control circuit for controlling operation of the overall image forming apparatus;
• a member to be heated;
• an excitation coil which is arranged in the vicinity of said member to be heated and heats said member to be heated by induction upon receiving a current;
• an induction heating control circuit which has a central processing unit independent from said main body control circuit, and controls current supply to said excitation coil;
• and
• sleep mode setting means for, when said image forming apparatus remains non-operated for not less than a predetermined period of time, setting said image forming apparatus in a sleep mode having lower consumption power than a normal state,
• wherein when a request for operating said image forming apparatus is generated while said image forming apparatus is set in the sleep mode by said sleep mode setting means, said main body control circuit supplies a heating ON/OFF signal to the central processing unit of said induction heating control circuit in correspondence with a type of generated request, and initializes required mechanisms of said image forming apparatus in accordance with the type of generated request.

An induction heating fixing device used in an image forming apparatus, comprising:

• a first CPU for controlling operation of the overall said image forming apparatus;
• a member to be heated;
• a thermistor, connected to the first CPU, for detecting a temperature of the heated member,
• an excitation coil, arranged in the vicinity of the heated member, for heating the heated member by induction upon receiving a current;
• an induction heating control circuit for controlling current supply to the excitation coil;
• and
• a second CPU for controlling operation of the induction heating control circuit;
• wherein the first CPU controls power supply to the induction heating control circuit according to the temperature detected by the thermistor and the second CPU controls current supply to the excitation coil.