Failure Detection - Canon LBP6670dn Series Service Manual

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Technology > Fixing System > Fixing control circuit > Failure detection

■ Failure detection

The DC controller determines a fixing unit failure, makes the FIXING HEATER CONTROL
signal inactive, releases the relay to interrupt power supply to the fixing heater and notifies
the Main Controller of a failure state when it encounters the following conditions:
1) Start-up failure (E000)
• If the detected temperature of the thermistor is kept a specified degrees or higher for a
specified period of heater start-up during the wait period.
• If the detected temperature of the thermistor is kept a specified degrees or lower for a
specified period under the heater temperature control during the initial rotation period.
• If the detected temperature of the thermistor is kept a specified degrees or lower for a
specified period under the heater temperature control during the print period.
• If the detected temperature of the thermistor does not reach its targeted temperature within
a specified period under the heater temperature control during the initial rotation period.
2) Abnormal high temperature (E001)
• If the detected temperature of the main thermistor is kept a specified degrees or higher for
a specified period.
3) Abnormal low temperature (E003)
• If the detected temperature of the thermistor is kept a specified degrees or lower for a
specified period under the heater temperature control.
4) Drive circuit failure (E004)
• If a specified frequency of the FREQUENCY signal is not detected within a specified period
after the printer is turned on.
• If an out of specified frequency of the FREQUENCY signal is detected after the printer is
turned on and the signal is once detected.
2 Technology > Fixing System > Fixing control circuit > Failure detection
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