hp deskjet 2540 not showing up as a scanner

Hello,

i have a macbook air and a hp deskjet 2540 all in one printer/scanner. i have been using it wirelessly for some time and have scanned before with no issues. Yesterday i went to scan a document and under my "printers and scanners" in system preferences the HP does not show up as a scanner (there is no scan tab). i have tried scanning thru capture and preview as well, no scanner is available anywhere in my computer. i have tried several times to delete the HP and re-install using both the HP software and not (letting apple fetch its own) and nothing changes. i know the scanner is still available and working because my wife can use it on her mac pro. i am out of ideas... any suggestions?