N-COUNT （施乐）复印机 A Xerox is a machine that can make copies of pieces of paper which have writing or other marks on them.

N-COUNT （施乐）复印件 A Xerox is a copy of something written or printed on a piece of paper, which has been made using a Xerox machine.

VERB （用施乐复印机）复印 If you Xerox a document, you make a copy of it using a Xerox machine.