Samsung CLP-770ND Service Manual page 92

Vertical Black Line and Band
1. Straight thin vertical black lines occur in the printed image
Description
2. Dark black vertical bands occurs in the printed image
Cause and Check Point
Check if the surface of the charge roller is scratched or
contaminated.
Check if there are grooves on the circumference of the
OPC drum.
Check if the cleaning blade is damaged
Is the charge roller of PTB unit damaged?
Check if paper transfer belt is damaged or
contaminated.
Vertical White Line
White vertical voids in the image.
Description
Cause and Check Point
Check if the LSU window or internal lenses of LSU is
contaminated.
Check if there are scratches on the circumference of
the OPC drum.
Check if there are scratches on the circumference of
the developing roller.
Foreign objects inside the toner cartridge.
Check if there are vertical scratches on the transfer
unit.
Service Manual
Alignment & Troubleshooting
Replace the toner cartridge and test again
Replace the toner cartridge and test again
Replace the toner cartridge and test again
Clean the charge roller of PTB unit, or replace the PTB
unit.
Replace the PTB unit and test again.
Clean the LSU window with recommended
cleaner(IPA). Clean the window with a clean cotton
swab. If dirt is inside the LSU, replace the LSU.
Replace the toner cartridge.
Replace the toner cartridge.
Replace the toner cartridge.
Replace the PTB unit.
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Solution
Solution
Samsung Electronics