C510 prints small coloured lines all over the sides of the printed page.

[trippp]

I have a Lexmark C510 printer that prints fine, except for the fact that it prints small coloured lines all over the sides of the printed page. The lines appear on exactly the same places on every page. What can be the cause of this? There are also some lines printed on different spots closer to the middle of the page.

[OMD-227]

Looks to me like the Transfer Belt Unit has worn edges. Take the Transfer Belt Unit out of the machine, check the side edges and compare to the marks printed on the page. The Transfer Belt is on a continuous loop, so the image shown will repeat down each page.
Have had this problem before. If your Transfer Belt is scratched/worn on the edges, its time for a new belt unit.