Canon LBP-2000, Руководство по обслуживанию

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CHAPTER 2
2 - 24
The AC power arriving at the low-voltage power supply circuit on the power supply PCB is con-
verted into three power levels (+24 V, +5 V, +3.3 V), and is sent to the DC controller PCB.
The +24 V may be either of the following two: +24 V which is stopped when the right door switch
(SW3) or the left door switch (SW4) is turned off (i.e., the front cover is opened), and +24 V which
is supplied regardless of the state of these switches.
The range of voltage levels arriving at the power supply PCB, rated outputs, and tolerances are
as follows:
•
Input voltage level range: AC input ±10%, 50/60 Hz ±2%
• Rated output and tolerance: +3.4 V ±3%; +5.1 V -4%, +3%; +24.0 V -5%, +10%
2 . Protective mechanisms
The power supply PCB is equipped with overcurrent protective functions and over-voltage protec-
tive functions, which are used to protect the power circuit from damage by automatically cutting
the output power in response to an overcurrent or an error voltage caused by a short-circuit or the
like in any of the loads.
If the output power is cut, turn off the power switch, disconnect the power plug, remove the
cause of activation, and leave the Printer alone for about 3 min or more before turning on the
power once again, thereby resetting the protective circuit.
The power supply PCB is also equipped with four fuses, which will blow if overcurrent flows into
the power line.
3 . Sleep mode (power saving mode)
The Printer enters sleep mode in response to a command from the video controller PCB to save on
its power consumption.
When a sleep mode command arrives form the video controller PCB, the CPU cuts power to the
loads and sensors (+24 V, +5 V), causing the Printer to enter the following state:
•
Fixing temperature: s t o p
• F a n : s t o p
• M o t o r s / s e n s o r : s t o p
The Printer returns to normal state when a command arrives from the video controller PCB to end
sleep mode when the /PRNT signal occurs or the Online key is pressed. (Note)
N o t e : When returning from sleep mode to normal mode (standby), the Printer executes initial
sequence (warm-up and warm-up rotation), requiring a maximum of about 30 sec for
recovery.