Power Supply - Canon LBP 2460 - B/W Laser Printer Service Manual

D. Power Supply
1. Outline
AC power is supplied to the low-voltage power supply when the main switch (SW101) is turned
ON. The low-voltage power supply generates the required +24VDC and +5VD for the printer.
+24VDC is supplied to the high-voltage power supply PCB to drive the main motor, scanner
motor, and fans. +5VDC is used for sensors and ICs on the DC controller PCB.
+24VDC is divided into +24VA which is normally supplied from the power supply and
+24VB which is shut OFF when the door switch (SW1401) turns OFF when the upper or
delivery covers are opened.
+5VDC is divided into +5V which is normally supplied to the ICs on the DC controller PCB
from the power supply and +5V for power-saving mode (P5VB1, P5BV2, P5VB3, and
P5VBDOR). Supply of +5V for the power-saving mode is stopped when the sleep command is
received from the video controller.
possible (when /RDY signal is "H"), the +5V is supplied off and on.
The DC controller PCB generates +5VC and supplies it to the laser driver.
This is shown in the block diagram below.

Power supply

Circuit Noise
breaker filter
Power
switch
(SW101)
Current
fuse
Noise
Voltage-raising
filter
converter
Control
IC
Input voltage
detection circuit
Low-voltage power supply circuit
: 220-240V ONLY
2. Protective Function
If a short circuit or other problems on the load side cause an excessive current flow from the
+24VDC or +5VDC power supplies, the excess-current protection system automatically shuts off
the output voltage to protect the power supplies.
During standby mode and periods when printing is not
To fixing roller heater
Relay
Phototriac
Triac
coupler
Surge current
Phototriac
Triac
reduction
coupler
resistor
Phototriac
Triac
coupler
Surge current
Phototriac
Triac
reduction
coupler
resistor
Rectification
Transformer
smoothing
circuit
Switching
FET
Constant-voltage
control
Control photocoupler
IC
Error state latch
photocoupler
Input voltage detection
photocoupler
Figure 2-2-13
DC controller
FSRTH
Current
RLD
transformer
/FSRD1E
Safety
/FSRCT1
circuit
/FSRD1
/FSRD1R
Current
/FSRD2E
transformer
/FSRCT2
Heater
drive
/FSRD2
circuit
/FSRD2R
/RLDSNS
+24VA
Rectification
FET
smoothing
circuit
/REMT 24
+5V
FET
Control
IC
PSTYP
CHAPTER 2
+5V Laser
driver
+5V
BD
PCB
+24VA
Scanner
motor
+24VB
High-voltage
power supply
Main
+24VB
motor
+5V
Sensors
Solenoids
+24VA
Clutches
+5V
Operation
panel
Switch
/sensor
PCB
Door
switch
(SW1401)
+24VB
+24VA
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