Ink Smudges

[Silverape]

I have a Canon Pixma ip4500. Recently, I have been getting black ink smudge lines on the centre of the back of my sheets and envelops. I have cleaned & aligned heads and cleaned rollers. Any other thoughts out there?

 

[Ian]

Hmmm... on the underside of the paper? It sounds like there's something on the roller, so if it's been cleaned then I'm confused as to what it could be.

Do you have a photo as that may give a clue as to what it could be .

If you feed a few sheets of scrap paper through (just do blank prints), does it fade gradually after each sheet?