I found this video: https://www.youtube.com/watch?v=TCKr5WgVVN8

The same applies for MFP printers, I checked mine : http://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/kb/docDisplay?javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken&javax.portlet.prp_ba847bafb2a2d782fcbb0710b053ce01=wsrp-navigationalState%3DdocId%253Demr_na-c02738751-1%257CdocLocale%253D%257CcalledBy%253D&javax.portlet.tpst=ba847bafb2a2d782fcbb0710b053ce01&ac.admitted=1409502745239.876444892.199480143

I pulled the HD from my mfp and docked it to my computer, I was able to retrieve EVERY DOCUMENT EVER PRINTED, COPIED or FAXED ON THIS MACHINE INCLUDING MY PAPER WALLETS !!!!!!