Hey you!
Try to print a drum test and see if it only appears when magenta and yellow drums are used.
try printing black and white.
If so it just might happen that the new drums are defect, been in a bright light for too long etc.
dirt/toner on the laser window would result in deletions and not colored lines.
Best Regards
Kimzi
--------------------------------------------
Please remember to select "Accept as Solution" for posts that helped you solve the issue.