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SMPS & HVPS (ALSO KNOWN AS PSU AND POWER PACK)
6.5 SMPS & HVPS
The SMPS and HVPS are on the same board.
The SMPS gives DC power to the system.
It gets 110V (NA model) / 220V (EU, AS and China models) and outputs the 5 V,
12 V and 24 V. Then it gives power to the main board and ADF board.
The HVPS generates the high voltage of THV/MHV/Supply/Dev for the developer
part. The HVPS gets 24V and outputs the high voltage for THV/MHV/BIAS. The
output high voltage goes to the toner, OPC cartridge, and transfer roller.
6.5.1 HVPS (HIGH VOLTAGE POWER SUPPLY)
Transfer High Voltage (THV+)
• Function: Moves developed toner on OPC drum to the paper.
• Output voltage: Maximum +5.0 KV ± 5% (Duty changeable, unload)
• 1.0 KV ±15% (When you clean, 200 MOhm)
• Error: If THV (+) does not output, a ghost image with low density shows.
Toner on OPC drum cannot correctly transfer to the paper.
Charge voltage (MHV)
• Function: Charges the OPC surface of with –900 V ~ –1000 V.
• Output voltage: -1.3 KV ~ 1.8 KV DC ± 50 V
• Error: If MHV does not output, a black paper is printed. This is because the
developing roller moves to a part of the OPC drum that does not get charge.
Cleaning voltage (THV-)
• Function: Cleans the surface. It sends minus toner from the transfer roller to
the OPC drum to get toner.
• Output voltage: There is no feedback control.
• Error: Toner contamination shows at the backside of a printed-paper.
Developing voltage (DEV)
• Function: Develops toner with different electronic potential on an exposed
part by LSU (Laser Scanning Unit).
* The electronic potential of exposed OPC is –180V and exposed developer
is –350 V when the machine prints. Toner with minus (-) develops on an
exposed part.
• Output voltage: –200 V ~ 600 V DC ±20 V
• Error:
1) If DEV is GND, density goes down.
2) If DEV floats due to an unstable contact point of terminal, etc., density
goes up.
B173
(ALSO KNOWN AS PSU AND POWER PACK)
6-10
SM
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