Our office has 5 of the MFC-L5850DW printers. Three of them are starting to get vertical creases in the paper when printing duplex. This only happens when printing duplex so I don't think that it is a fuser issue. It appears to be caused by the rollers when the paper is printed on the second side. Does anyone know of a fix? I found a guy who had some instructions on how to fix this exact problem a year or so ago but I lost this info. It seemed like he said that you had to replace some internal rollers. Any help would be much appreciated. Thank you.