I, too, have several HP 4050's that I use daily.
At first I started with the generic HP driver with Windows 10 and was
So, I started experimenting with some of the other drivers that HP
offered and found that using the PostScript (not PCL) LaserJet 4200
Driver from Windows Vista worked great and it allowed me to select both
ProRes 1200 (true 1200 dpi) and FastRes 1200 like it should.
I did have to tweak a few of the settings since the 4200 has more bins
than does the 4050, but otherwise, I'm most satisfied.
I am using the PostScript version of the driver since I found that the
PCL 6 implementation in the 4050's chokes on some of the code that
Windows sends it through the PCL 6 driver. With PostScript I'm error-free.
Since Windows 10 is a 64-bit system, I downloaded the 64 bit version of
the Vista 4200 driver. You many need the 32 bit version for Windows 8.1.
Finally, after I had this working fine for months, another kind soul
gave me a link to a special repository of LaserJet drivers, including
one specifically for the 4050 series. I did NOT change, however, since
the 4200 driver from Vista was doing the job.
But, here is the link:
Let us know if any of these work for you.
I agree, the LaserJet 4050s were built like tanks and will outlive most
of the folks who still use them. I bought mine over 20 years ago (also
with the envelope feeders) and use them every business day. I use them
with Windows, Mac OS X and even with my 30-year-old Apple II's.