Oki C9800 Series Service & Troubleshooting Manual page 62

Background
There is a very light covering of toner across the entire page. Background contamination
can appear in one of the primary colors or gray. The printer displays no error code.
Note
Depending on the type of paper and environmental conditions, some light amount of
random background spotting is normal. The whiter and glossier the paper, the more
noticeable it will be.
Initial Actions:
Perform Initial Actions from
Ask the customer about their typical printing habits. A high daily duty cycle can
temporarily fatigue the OPC drums within the Imaging Unit and contribute to unwanted
background toner.
Areas of the Printer that Apply to Background Issues
Imaging Unit
1. Is the printer in direct sun light?
2. Does the background appear to be in only one of the primary colors?
3. Check the Imaging Unit drum for toner contamination. Remove the Imaging
Unit of the problem color.
Is there a film of toner across the surface of the drum?
4. Verify the printer is operating within its environmental specifications. Low
humidity increases the degree of background toner.
5. Check the Transfer Unit belt. Is the background contamination a mixture of
colors and excessive?
Is the Transfer Unit belt contaminated with toner?
6. Is the customer printing on high-gloss media?
7. Check minimum clearances around the printer especially sides and back as it
can cause heat buildup.
Are clearances within specifications?
8. Test the Fans. Heat build-up under the Imaging Units can cause toner to stain
the background.
Are the fans operating correctly?
9. Check that the Imaging Unit contacts are in working condition and clean.
10. Remove the Imaging Units and the Transfer Unit and check for toner
contamination on the high voltage contacts.
Print Quality Troubleshooting Practices
Fuser Transfer Unit
Troubleshooting Steps
HVPS Engine Control Board
Yes – Move the printer.
No - Go to Step 2.
Yes – Go to Step 3.
No - Go to Step 4.
Yes – Replace the Imaging Unit.
No - Go to Step 4.
Yes – Go to Step 5.
No - Advise the customer of the
environmental specifications.
Yes – Replace the Transfer Unit.
No - Go to Step 6.
Yes – Advise the customer of the
limitation of this printer.
No - Go to Step 7.
Yes – Go to Step 8.
No - Advise customer.
Yes – Go to Step 9.
No - Replace the defective fan.
Yes – Clean the or replace the
drum contacts.
No - Go to Step 10.
Yes – Clean the contacts.
No - Replace in the following
order: Transfer Unit / HVPS
Resolution