Hello, my name is Rusty. That happens when there is ink on the rollers. It can get messy, and a little goes a long way. Open the front, and use a paper towel to clean the rollers where the black line is happening. Clean them as best as you can, then print a test page. Tell me the results.
Did you see ink on the paper towel?
How thick is the line?
Ok, there is likely debris on the scanner window. Since it is there the whole time, it goes from the top to the bottom of the page. Click here for cleaning instructions.
Ok, let me know when you get to it.
Do you see a smudge in the scanner window? Look closely, all it takes is one tiny spec of dirt.