Samsung CLP-770ND Service Manual page 94

Uneven Density
Print Density is uneven between left and right.
Description
Cause and Check Point
The pressure force in the left and right springs of the
transfer roller is not even, the springs are damaged,
the transfer roller is improperly installed
The toner layer is not even in the developing roller due
to the damaged blade or low toner level.
Poor the pressure spring force of the toner cartridge.
The life of the Toner Cartridge has expired.
Horizontal Bands
Dark or white horizontal stripes appear in the page.
Description
(These may occur at regular intervals down the page.)
Cause and Check Point
The developing roller, OPC drum or other rollers in the
toner cartridge may be contaminated or deformed.
Contamination of the Gap-Ring - regular intervals
38.9mm
Bad contacts of HV terminals of the toner cartridge with
high voltage terminals from printer set.
Contamination on the front of the page
The front page of the printed page is stained.
Description
Cause and Check Point
Toner leakage due to improperly sealed toner cartridge. Replace the toner cartridge.
Poor OPC cleaning.
Rollers and drum are dirty or defective.
Service Manual
Alignment & Troubleshooting
Replace the PTB Unit
Replace the toner cartridge
Replace the toner cartridge
Replace the toner cartridge
Replace the toner cartridge.
Clean the gap ring, or replace it. Or replace the toner
cartridge
Clean all HV terminals in the cartridge and on the set
frame. Ensure all toner or paper dust, particles are
removed.
Replace the toner cartridge.
Identify the roller which may cause the problem by
comparing the period of the contamination on images
with the size of rollers. Clean any dirt from the roller or
replace the dirty roller or part.
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Solution
Solution
Solution
Samsung Electronics