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Technical Reference > Fixing System > Protective Functions > Fixing assembly failure detection
Technical Reference > Fixing System > Protective Functions > Fixing assembly failure detection
Protective Functions
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Protective function
The protective function detects an abnormal temperature rise of the fixing assembly and
interrupts power supply to the fixing heater.
The following three protective components prevent an abnormal temperature rise of the fixing
heater:
• DC controller
• Fixing heater safety circuit
• Thermal fuse
1) DC controller
The DC controller monitors the detected temperature of the thermistor located at the center
of the fixing heater. The DC controller sets the FIXING HEATER DRIVE (FSRD+, FSRD-
) signals to inactive and releases the relay to interrupt power supply to the fixing heater
under the following condition:
• Thermistor: 230 deg C or higher
2) Fixing heater safety circuit
The fixing heater safety circuit monitors the detected temperature of the thermistor located
at the center of the fixing heater. The fixing heater safety circuit releases the relay to
interrupt power supply to the fixing heater under the following condition:
• Thermistor: 240 deg C or higher
3) Thermal fuse
When the temperature of the fixing heater rises abnormally high and the detected
temperature of the thermal fuse is the following condition, the fuse blows to interrupt power
supply to the fixing heater:
• Thermal fuse: 226 deg C or higher
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Fixing assembly failure detection
The DC controller determines a fixing assembly failure, sets the FIXING HEATER DRIVE
(FSRD+, FSRD-) signals to inactive, releases the relay to interrupt power supply to the fixing
heater and notifies the main controller of a fixing assembly failure when it encounters the
following conditions:
1) Start-up failure
• If the detected temperature of the thermistor does not reach 40 deg C within a
specified period from the heater energization during the wait period.
• If the detected temperature of the thermistor does not reach 70 deg C within a
specified
period after it once reaches 40 deg C after the heater energization during the wait
period.
• If the detected temperature of the thermistor does not reach the targeted temperature
within a specified period under the heater temperature control during the initial rotation
period.
2) Abnormal low temperature
• If the detected temperature of the thermistor is kept 100 deg C or lower for a specified
period under the heater temperature control during the print period.
3) Abnormal high temperature
• If the detected temperature of the thermistor is kept 230 deg C or higher for a specified
period.
4) Fixing heater drive circuit failure
• If the specified count of the ZERO CROSSING signal is not detected within a specified
period after the printer is turned on.
• If the ZERO CROSSING signal is not detected for a specified period during the print
period after the signal is once detected after the printer is turned on.
Summary of Contents for Color imageRUNNER LBP5280
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Page 276: ... General Timing Chart General Circuit Diagram Signal Input Output List Appendix ...
Page 283: ...6 8 6 8 Appendix Backup Data Appendix Backup Data ...
Page 284: ...6 9 6 9 Appendix Backup Data Appendix Backup Data ...