Fixing Heater Error Activation Detection Circuit - Canon NP6251 Service Manual

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CHAPTER 6 FIXING SYSTEM

As a result, the relay inside the power supply switch will be supplied with power, the

power switch will be turned off, and the AC power supply will be cut off (error auto power

3. Fixing Heater Error Activation Detection Circuit

The gate array generates the fixing heater ON signal (SSR ON), and receives the

fixing heater ON detection signal (SSR ACTIVE). An error is identified if the fixing heater

is on in the absence of the fixing heater ON signal.

At this time, the gate array communicates an error in the activation of the fixing

heater to the master CPU and, at the same time, generates the power switch OFF signal.

In addition, the thermistor used to monitor the surface temperature of the fixing roller

generates the error signal (FUSER TEMP ERROR) to the gate array. The gate array will

also turn off the power switch in response to an abnormal increase in the surface

temperature of the fixing roller.

When the power supply switch OFF signal is generated, the relay inside the power

switch is powered to turn off the power switch and the AC power supply.

If the fixing sub thermistor (TH2) detects an abnormal increase in temperature (230

±10°C), the DC controller PCB indicates 'E001', and turns off the AC power supply.

The machine checks the fixing sub thermistor for a broken line, and indicates 'E000'

for about 5 sec if it finds an open circuit and cuts off the AC power supply.

Figure 6-110

CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)

DC controller PCB

Power switch OFF

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