Overheat Protection (B129/B130/B168/B169) - Gestetner B130 Service Manual

Rev. 11/2004

6.22.14 OVERHEAT PROTECTION (B129/B130/B168/B169)

The BICU references the fusing
temperature through the thermistor
([A] in the illustration for 6.7.6). The
copier prevents overheating as
listed below. Normally, Feature 1 is
effective in preventing overheating.
Features 2 through 3 are fail-safe
features.
Feature 1:
The BICU turns off the fusing lamp when the fusing temperature is too high.
Feature 2:
The BICU disables the machine operation when the thermistor detects an abnormal
temperature transition. In a case like this, the copier displays one of the following
SC codes ( 4.1.2): SC543, SC544, SC545, SC546.
NOTE: If the fusing temperature is too low, SC542 is displayed.
Feature 3:
The BICU disables the machine operation when the thermistor does not operate
properly. In a case like this, the copier displays SC541 (
Feature 4:
The thermoswitch near the center ([B] in the illustration for 6.7.6) cuts the power
supply to the fusing lamp at 160°C. The thermoswitch near the end [C] cuts the
power supply to the fusing lamp at 170°C. These thermoswitches and the fusing
lamp are on the same circuit.
NOTE: 1) Thermoswitch temperature is somewhat lower than the fusing
temperature.
2) The thermoswitch near the center does not necessarily work earlier than
the other thermoswitch. The ends of the hot roller can be much hotter
than the center when, for example, paper of a small size is continuously
going through the fusing unit.
Feature 5:
The BICU disables the machine operation when the exhaust fan does not operate
properly. In a case like this, the copier displays SC590 (
Note that defective exhaust fans may cause overheating.
SM
CÓPIA NÃO CONTROLADA
[A]
[B]
[C]
6-65
CÓPIA NÃO CONTROLADA
IMAGE FUSING AND PAPER EXIT
4.1.2).
B129 Series/B044 Series
4.1.2).