Not long ago, I started a thread on this forum regarding scratching of paper surfaces by my Epson 3880 printer. The scratches were long straight lines parallel to the direction of paper travel and only occurred with 17 x 22 inch sheets of Ilford Gold Fibre Silk and Canson Infinity Baryta papers, both of which have alpha cellulose paper bases. After discussing the matter with Epson, they were kind enough to send me a brand new 3880 that, sadly, exhibited the same behavior.
At that point, I decided to try my luck with a 100% cotton rag paper, hoping that it would be less prone to buckle in the printer when it becomes moistened by the ink. On the recommendation of Erik at Shades of Paper, I ordered a box of Canson Platine 17 x 22 inch sheets. I am very pleased to report that the Platine shows no scratches whatsoever, even with a really dark B&W image having large areas of dense black ink. So the scratching issue seems to be related to alpha cellulose paper buckling as it passes through the paper pathway of the 3880 (and presumably the 3800.) Although I had to go through a period of much aggravation, I am happy to have found the solution. It also helps that Platine is a beautiful paper with no OBAs. I will most likely make it my paper of choice for now, while I continue to test other rag papers.
I hope that this will be of help to others with the 3800 and 3880 printers.
Rob