Xerox W/C 5855 blurries

[landspeeder]

I have a client with a W/C 5855 and when they scan to a pc sometimes you get like a halo around the characters, you get a blurriness almost like the toner didnt get fused but this is a scan to PC.... Its random, their paper is of very good quality with nothing special about it. They say it never happins with doing just a copy but I myself have a hard time with that as the same scanner is used for both copying and scanning. maybe its a different board...I dont know!
Thanks