Canon LBP1760P, Service Manual

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c. Heater broken wire detection
The CPU detects heater broken wire in the following cases and assesses warm-up error or abnor-
mally low temperature.
1) The thermistor, in the low-temperature detection mode, does not rise +10
°
C from the initial
temperature within about 2.5 seconds after the heater is turned ON.
2) The thermistor, in the low-temperature detection mode, does not rise +20
°
C from the initial
temperature within about 2.5 seconds after 10
°
C from the initial temperature since
the heater is turned ON.
3) The thermistor, in the high temperature detection mode, does not exceed about 160
°
C with-
in about 20 seconds after 20
°
C from the initial temperature since the heater is turned
ON.
4) When the thermistor is in the high temperature detection mode and the initial temperature
is 85
°
C or below, the temperature does not exceed about 160
°
C within about 20 seconds
after the heater is turned ON.
5) When the thermistor is in the high temperature detection mode and the initial temperature
is 85
°
C or more, it does not exceed about 160
°
C (about 140
°
C in case of 1200DPI) within
about 6 seconds after the heater is turned ON.
6) During print temperature control, the condition of below about 150
°
C (about 130
°
C in case
of 1200DPI) lasts for more than about 1 second continuously.
d. Abnormally high temperature detection
The CPU assesses abnormally high temperature detection if the thermistor in the high temper-
ature detection mode detects over about 220
°
C for more than about 100ms continuously,
regardless of the heater operation condition.
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CHAPTER 2