Canon M3010 Series, Руководство по обслуживанию

Страница: 36 / 133

2
2
2-21
2-21
Technical Overview > Fixing System > Various Control Mechanisms > Protective Functions
Technical Overview > Fixing System > Various Control Mechanisms > Protective Functions
2) Protection function by fixing heater safety circuit
Fixing Heater (H1) safety circuit monitors the Thermistor (TH1) temperature consistently.
When Thermistor (TH1) reaches approx 235 deg C, it determines that the Fixing Heater (H1)
is overheating and the fixing heater safety circuit turns OFF the relay drive circuit to shut
the power supply to the Fixing Heater (H1).
3) Protection function by Temperature Fuse (TP1)
When the Fixing Heater (H1) temperature rises abnormally and Temperature Fuse (TP1)
temperature reaches approx 226 deg C, Temperature Fuse (TP1) opens to shut the power
supply to the Fixing Heater (H1).
●
Failure detection
With this machine, 10 types of failure detection are available.
1) Initial startup failure detection
When temperature of the Fixing Assembly does not exceed 50 deg C within 1.48 sec after
the start of temperature control performed at initial rotation, it is judged as initial startup
failure.
2) Initial Thermistor open detection
When temperature of the Fixing Assembly does not exceed 35 deg C within 1.48 sec after
the start of temperature control at warm-up rotation temperature control or at cleaning
mode, it is judged as Thermistor open failure.
3) Short circuit of Thermistor/abnormal high temperature detection
When temperature of the Fixing Assembly is 220 deg C or higher for 30 consecutive times
by monitoring the temperature for every 5 msec, it is judged as Thermistor short circuit
failure. In addition, this function also doubles as abnormal high temperature detection
function of the Fixing Assembly.
4) Abnormal low temperature detection
After temperature of the Fixing Assembly exceeds 50 deg C at least once, monitor
temperature of the Thermistor (TH1) for every 5 msec. It is judged as heater abnormal
low temperature when the following condition is detected 240 consecutive times: the
temperature is 100 deg C or lower while paper is at fixing nip, or it is 55 deg C or lower
during paper interval temperature control or at cleaning mode.
5) Thermistor open detection
After temperature of the Fixing Assembly exceeds 50 deg C, monitor temperature of the
Thermistor (TH1) for every 5 msec. When it is detected that the temperature is lower than
20 deg C for 6 consecutive times, it is judged as Thermistor open failure.
6) Startup failure detection
If temperature of the Fixing Assembly is 100 deg C or higher when the machine becomes in
pickup enabled state after entering fixing low voltage inlet sequence, it is judged as startup
failure.
7) Thermistor high temperature detection 2
Temperature of the Thermistor (TH1) is monitored every 200 msec during Fixing Assembly
control. If the temperature is equal or higher than "detection temperature of Thermistor high
temperature detection 2", increase the value of "high temperature detection counter" by 1
(+1). If not, decrease the value by 1 (-1). When the value of "high temperature detection
counter" b50, it is judged as a Thermistor high temperature failure. The default
and minimum value of "high temperature detection counter" is 0.
The "detection temperature of the Thermistor high temperature detection 2" is set to 195
deg C when the target control temperature is 180 deg C or less. When the target control
temperature is above 180 deg C, it is set to "target control tempe approx. 15 deg
C".
8) Thermistor low temperature detection 2)
Temperature of the Thermistor (TH1) is monitored for every 200 msec when paper is at
fixing nip during the Fixing Assembly control. When the temperature is lower than 135 deg
C (120 deg C), increase the value of low temperature detection counter by 1 (+1). When
it is 135 deg C (120 deg C) or higher, decrease the value by 1 (-1). When the value of low
temperature counter b150, it is judged as Thermistor low temperature failure. The
default and minimum value of low temperature detection counter is 0.
9) Frequency detection circuit error (230V models only)
When frequency measurement is not completed within 3255 msec after the completion of
previous frequency measurement, it is judged as frequency detection circuit error.
10) Thermistor high temperature detection 3
Temperature of the Thermistor (TH1) is monitored every 5 msec, and if the temperature
is equal or higher than "detection temperature of Thermistor high temperature detection
2 + approx. 15 deg C" more than 30 consecutive times, it is judged as a Thermistor high
temperature failure.