I have a Dell 5100CN, and believe that this problem is caused by the drum not releasing the full charge which holds the ink in place on the drum until the page is printed. After the image is transfered to the Drum, the 'Fuser' unit heats up the paper and pressure forces the paper against the drum to transfer the toner from the drum to the paper.
Since the Image is printing, and you are getting a ghost, I guess that the problem is most likely the 'Pressure Roller' or 'Heater' in the 'Fuser' unit.
Buying the Fuser unit from Dell could cost you around $200 from Dell, but I just found one on eBay for $129 Got to
www.ebay.com and search for item number 190388919845
I highly recommend that you buy a new OEM (original Equipment Manufacturer (Genuine Dell)) 'Fuser Unit'
Good Luck