Olivetti d-Color MF4003 Service Manual page 624

d-Color MF4003/MF3303
• If the heating roller thermistor/1 detects a predetermined temperature or more continuously, the temperature is determined to be
abnormally high and a "trouble code C3722: Fusing abnormally high temperature detection (Edge of the heating side)" will be
displayed.
• If the heating roller thermistor/2 detects a predetermined temperature or more continuously, the temperature is determined to be
abnormally high and a "trouble code C3726: Fusing abnormally high temperature detection (Center of the heating side)" will be
displayed.
• When the trouble code is displayed, printing will be prohibited.
(b) Second approach: hardware protection
• A different protection is provided when the CPU overruns, becoming unable to detect the malfunction of an abnormally high
temperature. If the fusing temperature sensor/2 (TEM2) detects an abnormal temperature, the heater relay of the DC power supply is
turned OFF through the printer control board. Power supply to the fusing heater lamp is then shut down.
• When the hardware circuit in the DC power unit detects the heater relay being OFF, the temperature is judged to be abnormally high.
Trouble code C3725: Fusing abnormally high temperature detection (TEM1:center) will be displayed.
• Through these control procedures, the power supply to the heater lamps can be shut down before the thermostat is activated. It
thereby suppresses damage to the fusing unit itself.
(c) Third approach: thermostat protection
• If detection of the abnormally high temperature through approaches 1 and 2 above is not possible due to a defective the heating roller
temperature sensor, heating roller thermistor or other reason, the thermostat comes into play to shut down the power supply to the
heater lamp.
(5) Fusing PPM control
(a) PPM control
• To achieve the intended level of fixability of printed images, the PPM control reduces the number of printed pages per minute by
widening the distance between sheets of paper.
PPM mode
Low temperature
environment mode
High humidity environment
mode *2
Paper curl suppression
mode
Heating roller end
temperature rise
suppression mode
Reduced power supply
mode
Recycled paper
correspondence mode
Service Manual
Control execution Purpose
conditions
Room temperature at the To achieve the intended
start of the print cycle is level of fixability under low
less than 18 degrees temperature environment
Environmental humidity at To suppress occurrence of
the start of the print cycle paper curl under high
is a predetermined value humidity environment
or more
"Mode 3" is selected for To suppress occurrence of
"Change Warm Up Time" paper curl under
of the service mode conditions other than high
humidity environment
• Print request is To suppress inordinate
received for paper rise in temperature on
with a paper width of heating roller ends in a
209 mm or less print cycle using paper of
• Temperature of the a small size
heating roller ends
becomes a
predetermined value
or more
Only an insufficient power To achieve the intended
is supplied to the fusing level of fixability under low
heater lamp, resulting in a power supply condition
fusing temperature lower
than a predetermined
value
"100%" is selected for To increase the print
"PPM Control Choice" of productivity of recycled
the service mode paper.
* Paper curling can
increase if 100% is
selected.
P THEORY OF OPERATION > 1. d-Color MF4003/MF3303
Specific controls
To prevent fixability from
being degraded in a multi-
print cycle, paper-to-paper
distance is widened to
thereby limit a decrease in
the fusing temperature.
Paper-to-paper distance is
widened in a multi-print
cycle run under high
humidity environment so
as to prevent paper from
curling, thereby achieving
a required fusing
temperature.
Paper-to-paper distance is
widened in a multi-print
cycle run under any
condition other than high
humidity environment so
as to prevent paper from
curling, thereby achieving
a required fusing
temperature.
Paper-to-paper distance is
widened in a multi-print
cycle so as to prevent the
temperature on ends of
the heating roller from
increasing, thereby
promoting reduction in
temperature.
To prevent fixability from
being degraded in a multi-
print cycle, paper-to-paper
distance is widened to
thereby limit a decrease in
the fusing temperature.
Paper-to-paper distance is
narrowed to thereby
increase productivity.
P-50
Print productivity *1
100%
90%
80%
70%: default
60% 5
0%
100%
70%
50%: default
100%
50%: default
100%: default value
90%
80%
70%
60%
50%
40%
30%
100%: default value
70%
50%
100% 70%: default value
*3
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