Have a C3130 in a copy shop with around 46,000 count. Its been leaving dark marks on the lead edge of prints, mainly in-line with an image(not text) on the front. If you stack say around 100 pages you can very well see the marks, can hardly see it if looking at just one copy. One tech messed with some adjustments in the fuser(nip adj. I think) and we thought it went away but customer said it hasn't changed. Any thoughts before I bring in tech rep??