Lexmark W850n Service Manual page 107

Vertical blank lines (white stripes in media transport direction)
Leading edge
Trailing edge
Step Check
1 Check the media condition.
Load new, dry, recommended media.
Re-print the defective image.
Does the error continue?
2 Are the media transfer route and the media path clear of
debris?
3 Check laser beam route.
Check for debris between the transfer roll assembly and
the PC drum.
Check the printhead assembly window for contamination.
Is there any debris in the laser beam route, and is the
printhead assembly window free of debris and
contamination?
4 Check the printhead assembly installation.
Is the printhead assembly installed securely with four
screws?
5 Check the printhead assembly installation.
Install the printhead assembly securely and perform a print
test.
Does the error continue?
6 Check the toner cartridge.
Install a new toner cartridge.
Re-print the defective image.
Is the image density normal?
7 Check the transfer roll assembly.
Remove the transfer roll assembly.
Is the transfer roll assembly rotating, free of contamination
and wear?
Yes No
Go to step 2. Problem solved.
Go to step 3. Remove debris or
contamination.
Go to step 4. Remove debris,
or clean the
printhead
assembly window.
Go to step 6. Go to step 5.
Problem solved. Go to step 6.
Problem solved. Go to step 7.
Go to step 8. Replace the
transfer roll
assembly.
Diagnostic information
4024-110
2-87