Epson R1800 printing problem Help !!!

What paper are you using?  It is possible you're getting a head strike at the end of the print, which would result in those marks.

You might try setting the "Thick Paper" option.  In Windows go to the Maintenance tab, click Printer and Option Information then check the Thick Paper box.

On a Mac find the Extension Settings menu from the print dialog for that control.

Also, you can try giving the trailing edge of the paper a downward curl so that it pushes down against the platen.  This should help keep the paper down and away from the head.

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Drew Hendrix VP / Tech Support Manager Red River Paper