I bought these HP cartridges on Ebay: http://www.ebay.com/itm/182104575806?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT with no mention of the expiration dates so I assume a few months to maybe a year. Turns out they expired in 2010 and 2011. Any problems using them?