Might be drum failure or one of the rollers. When that happen you will get the problems on every page consistently on the same exact spots, in fact the pattern repeats across the page. If you dare and have enough patience, you can try cleaning the rollers and drum taking the needed cautions, once clean you will probably get ONE clean print and then the problem will appear again (it's just to confirm), in fact you might see the damage on the rollers yourself.
If this is the case... you'll have to replace the failing parts.
*Sometimes... what fails is a rubber/plastic/whatever piece that keeps the rollers clean like a windshield cleaner, repairing complexity depends on your model. IMH experience once these things happen it's cheaper to get a new one.
