Lexmark has implemented the PS command setenginesync in the statusdict.
Could we replicate this for HP LaserJets with something like:
@PJL ENTER LANGUAGE = PCL
ESC&r1F <--- Flush all pages: should this be ESC*s1F?
? Works fine on LJ4000 and LJ2200 printers, but not on the newer LJ4100. Could we use 'PJL TEOJ=ON' on the LJ4100?