Samsung Lazett Combo SCX-4216F, Service Manual

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4-14
SUMMARY OF PRODUCT
Samsung Electronics
Service Manual
4.4.1 HVPS(High Voltage Power Supply)
1) Transfer High Voltage (THV+)
- Function : Voltage to transfer developed toner on OPC drum to a paper.
- Output voltage : +1300V DC±20V
- Error : If THV (+) doesn't output, a ghost status (same character is printed after one cycle (76mm)
of OPC) with a low density occurs due to a toner on OPC drum cannot normally transfer to
a paper.
2) Charge Voltage (MHV)
- Function : It is a voltage to charge entire surface of OPC with -900V ~ -1000V.
- Output voltage : -1550V DC ± 50V
- Error : If MHV doesn't output, a black paper is printed out because toner on developing roller
moves to OPC drum due to the surface of OPC not being charged.
3)Cleaning Voltage (THV-)
- Function : It removes a dirty on a surface by sending a minus toner in a transfer roller to an OPC
drum to recover toners.
- Output Voltage : +300V/-150V
- Error : Toner contamination occurs at the backside of a printed-paper.
4) Developing Voltage (DEV)
- Function: It is a voltage to develop a toner with using a difference of electronic potential on an
exposed part by LSU (Laser Scanning Unit).
* Generally, the electronic potential of exposed OPC is -180V and exposed developer is -350V
when printing, so toner with minus (-) is developed on an exposed part.
- Output voltage: -430V DC ± 20V
- Error: 1. If DEV is GND, a density is going significantly down.
2. If DEV is floating due to instable contacting point of terminal, and etc., a density is signif-
icantly going up.
5) Supply Voltage (SUP)
- Function: It is a voltage to supply toner to a developing roller.
- Output voltage: : -630V DC ± 50V (Use ZENER, DEV Gear)
- Error: 1. If SUP is GND, a density is dramatically going down.
2. If SUP is floating due to instable contacting point of terminal, and etc., a density is signif-
icantly going down as much as it cannot be recognized with eyes.