Canon CLBR 460ps Service Manual page 84

CHAPTER 2
door switch (SW5) is turned OFF by opening the drum cartridge drawer, ITB unit drawer, toner
cartridge door, or delivery door and +24VB, which is always supplied whether SW4 and SW5 are
turned ON or OFF.
The low-voltage power supply circuit monitors the 5VS signal fed back from the connector
PCB to ensure the 5V power supply to the video controller.
2. Remote Switch
When the power switch of the printer is turned OFF, the power supply circuit output the POWER
OFF signal (PSWOFF) to the DC controller PCB. The DC controller PCB sets the POWER OFF
CONTROL signal (PCONT) to "L" in 10 minutes after the power switch is turned OFF (see note).
This turns OFF switching transistor and stops +5V, 3.3/+5V, and +24VB power supplies.
Note: The fan is driven for 10 minutes after power-OFF in order to lower temperature in the
printer.
3. Protection Function
Each DC power supply circuit has an overcurrent protective function and overvoltage protective
function, which prevent power supply circuit failure by automatically interrupting the output
voltage when troubles, such as short, develop on the loads and result in overcurrent flow or
abnormal voltage.
If these functions are activated and no DC voltage is output from the low-voltage power sup-
ply circuit, turn OFF the power switch (SW6), unplug the power cord, rectify the trouble on the
load, and then turn ON the power switch again. (See note)
The low-voltage power supply circuit contains the circuit breaker (CB101) and fuse (F1).
When excessive current flows, the CB101 is turned OFF or the F1 is cut to interrupt the power
supply.
Note: Protective functions remain active for 2 minutes after activation. Wait at least for 2 min-
utes to turn the power back ON again.
4. Power-saving mode
This printer enters the power-saving mode, which is called the sleep state, when the command
from the video controller is received. The sleep state consists of 2 levels which are also deter-
mined by the command from the video controller.
In response to the power-saving command sent from the video controller, D-CPU shuts off the
+24V and +5V power supplies, which drive various loads and sensors, according to the sleep
level of the power-saving command.
Fixingtemperature
Sleep level
control
Level1
Level2
It returns to the normal mode when a command is received to cancel the power-saving mode
from the video controller.
If the sleep command is sent during printing or initialization, the printer enters the sleep state
after the completion of the operation. (See note)
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Table 2-2-1
Fan
Stop Half-speed
Stop Stop
Motors/sensors Remarks
Stop Lightsleep
Stop
Deep sleep