A:Answer Good question. They are both new printers and there are differences between them. The 6978 has a few more features than the 6968. The 6978 has a USB port so that you can scan and save documents to a flash drive where as the 6968 does not have a USB port. Also, the 6978 does automatic double sided scanning and copying. On the 6968, if you have a double sided document to scan, you have to manually flip the page over to scan the other side.
I hope this helps.