Canon Laser Shot LBP-5100, Руководство по обслуживанию

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Chapter 2
2-33
2.6.2.1.2 Fixing Temperature Control
0015-9294
LBP5100
The machine monitors the surface temperature of the fixing heater, and controls the drive signal of the fixing heater so that the temperature will be identical to the
target temperature.
F-2-37
The temperature of the fixing heater is checked by 2 thermistors: main thermistor (TH1), sub thermistor (TH2).
TH1 is used for printing temperature detection and sheet-to-sheet temperature control, while TH2 is used to check for edge overheating.
The CPU (IC7) on the DC controller PCB monitors the voltage of these 2 thermistors, and generates the fixing heater drive signal (FSRD) according to the level of
the voltage.
The machine's fixing temperature control mechanism uses the following 5 sequences of operation:
1. Initial Multiple Rotation Temperature Control
The machine executes initial multiple rotation temperature control to prevent tears in the fixing film by melting the grease on the inner side of the film at power-
on for smoother belt movement.
If the reading of the sub thermistor is lower than 55 deg C at power-on, the CPU turns on the fixing heater for a specific period of time before it starts the fixing/
delivery motor.
2. Start-Up Temperature Control
The machine executes start-up temperature control to determine the start-up temperature for the fixing heater to suit the reading of the main thermistor detected
when turning on the heater. If the heater is turned on within 40 sec after the end of the previous print job, the previous printing temperature is used for the
upcoming print job.
3. Printing Temperature Control
The machine executes printing temperature control so that the temperature of the fixing heater will be identical to the target temperature during printing.
In continuous printing mode, the machine changes the target temperature in stages according to the specified number of prints
Heavy paper 2 Number of sheets passed 1-2 3-6 7-13 14-25 26-
Initial rotation temperature 165 158 155 150 145
Printing temperature 170 168 165 160 155
Sheet-to-sheet temperature 160 158 155 150 145
Thin paper Number of sheets passed 1-5 6-17 18-37 38-73 74-
Initial rotation temperature 194 174 162 156 149
Printing temperature 189 184 177 171 164
Sheet-to-sheet temperature 189 179 172 166 159
Envelope Number of sheets passed 1-2 3-6 7-13 14-25 26-
Initial rotation temperature 165 158 155 150 147
Printing temperature 170 168 165 160 157
Sheet-to-sheet temperature 160 158 155 150 147
Transparency Number of sheets passed 1-2 3-6 7-13 14-25 26-
Initial rotation temperature 170 168 161 157 153
Printing temperature 175 173 171 167 163
Sheet-to-sheet temperature 170 168 161 157 153
Mode
Temperature
control 1
Temperature
control 2
Temperature
control 3
Temperature
control 4
Temperature
control 5
Fixing heater (H100)
Thermal fuse (FU100)
Fixing film unit
Main thermistor
(TH1)
Fixing heater
safety circuit
Low-voltage power supply unit
IC7
CPU
DC controller PCB
Sub thermistor
(TH2)
FSRD
Fixing unit
SUBTH
MAINTH
RLD
RLD+
RLD-
ZEROX
Fixing control circuit
+24V
+3.3V
RL901
Relay drive
circuit
Fixing heater
drive circuit
Zero crossing
circuit
+3.3V