I called earlier today and talked to a great person in tech support that suggested the same thing and offered to send out a black drum at no charge.
Great service! I'll install and test when it arrives.
It could be from the black drum cartridge. I will recommend you to claim the warranty.
It looks like my issues is exactly twice the distance of the Fuser (63mm). Every second blotch matches that mark. Does that make any sense?
I purchased a brand new 6510 dn, and from the first page, I had this repeating smudge on the right hand side. I've done the cleaning from the admin menu, and printed a defects sheet, but it does not line up.
This printer has 33 copies... so maybe it needs to be broken in?
I am using all the consumables which were installed from the factory.