The problem of ljet4 alwyas giving one-sided printing and ljet4d always giving duplex printing can be easily solved in Foomatic, but the problem should also get fixed in Ghostscript so that standard PostScript methods for using duplex get working.
Can you try the ljet4d driver and there select the long-edge and short-edge versions of duplex printing. Does this at least correctly work?
The problem of ljet4 alwyas giving one-sided printing and ljet4d always giving duplex printing can be easily solved in Foomatic, but the problem should also get fixed in Ghostscript so that standard PostScript methods for using duplex get working.
Can you try the ljet4d driver and there select the long-edge and short-edge versions of duplex printing. Does this at least correctly work?