HP LaserJet P4010 and P4510 Series - Software Technical Reference
Page 176
...when the duplexing feature has been selected in the Properties print-driver tabs. All media types support the smart duplexing feature, except for media types that cannot be printed on the other HP LaserJet P4010 and P4510 Series printer models for media types that the automatic duplexing unit does not...When the media type is known as fuser temperature and print speed) to use a group of the media because the HP LaserJet P4014, P4014n, P4015n, P4015tn, P4515n and P4515tn printer models do not have a duplexing unit installed. To make the Print on Both Sides (Manually) check box available in...
...when the duplexing feature has been selected in the Properties print-driver tabs. All media types support the smart duplexing feature, except for media types that cannot be printed on the other HP LaserJet P4010 and P4510 Series printer models for media types that the automatic duplexing unit does not...When the media type is known as fuser temperature and print speed) to use a group of the media because the HP LaserJet P4014, P4014n, P4015n, P4015tn, P4515n and P4515tn printer models do not have a duplexing unit installed. To make the Print on Both Sides (Manually) check box available in...