In which forum should I ask IBM related questions?
Forum: Printers from Lexmark and IBM 
Where can I find a table of working IBM printers?
Is this a Lexmark printer?
Yes. This is a Lexmark 4029 laser printer.
How do I make this printer PostScript?
There is an IBM field upgrade module that allows you to add PostScript
Why does the upgrade module not understand PostScript?
The upgrade module provides PostScript level 1. Since most applications
produce PostScript level 2, they cannot use the PostScript feature of this
There are four workarounds.
1. Use PCL. Try the ljet3 and ljet4 drivers. This has been
reported working with limited success (there are shades of grey in the
2. Use GhostScript to convert the PostScript Level 2 to Level 1. This
has not been tested, but is an IBM recommended solution.
gs -q -sDEVICE=pswrite -dNOPAUSE -dSAFER -dPARANOIDSAFER -dLanguageLevel=1 -sOutputFile=level1.ps filename.ps
3. Use Acrobat to convert the file. This has been reported working.
cat file.pdf | acroread -toPostScript -level1 > file.ps
4. Try setting up foomatic to print PostScript level 1.
See the Mac OSX faq entry about setting up PostScript Level 1</a>.
See this page 
for more informatino from IBM.
Where can I get a manufacturer PPD?
Lexmark offers some PPD's.