Oki ES3640MFP Service & Troubleshooting Manual page 55

Mottled or Splotchy Prints
The print image has a mottled appearance.
Note: This defect is known to occur when manually duplexing, at low humidity, and when
printing on heavy weight media.
Initial Actions
Perform Initial Actions from
Areas of the Printer that Apply to Mottled or Splotchy Prints
1. Ensure the media is approved and the Control Panel and driver settings match
the loaded media. Try different media to verify consistent, reproducible problem.
2. Print the configuration page to verify the operating environment.
NOTE: Low humidity, less than 20% relative humidity can cause mottling on
prints.
3. Check for toner contamination on the high voltage contacts. Remove the
Imaging Units and Transfer Unit. Is there contamination?
4. Check / Replace the Transfer Unit. Is the problem resolved?
Print Quality Troubleshooting Practices
Imaging Unit
LED Head
HVPS
Engine Control Board
Troubleshooting Steps Resolution
Yes – Go to Step 2
No - Have the customer load
approved media or correct the
settings.
Yes – Go to Step 3
No - Advise customer regarding
the printer's environmental
specifications.
Yes – Clean the contacts
No - Go to Step 4
Yes – Complete
No - Replace in the following
order: LVPS / HVPS / Engine
Control PCB