I do a fair amount of downloading of forms to the LaserJets.
 
The book I use for the commands is the HP PCL 5 PRINTER LANGUAGE TECHNICAL
REFERENCE MANUAL.   Part Number 33459-90903.  A cupon came with the LaserJets
that you returnrd asking for this manual (it was free - some 600-700 pages)
may not be free now.  I documents ALL laser commands.
 
Chapter 10 deals with soft font creation / handling.  I believe you can buy
all the soft fonts you want for less than $100.
 
The next trick ( if using the HP3000) is to download via the spooler.
You need to call an intrinsic to open the print file to handle lon string
files without inserting extraneous CL/LF.  I have that program here
somewhere- it's written in TRANSACT.  I literally COPY my forms to the laser
and then overlay them over my application with laserjet macro's.
 
You can do some real neat things in PCL5.  You will like the book - its full
of examples- unusual for a HP Tech Ref Manual.
 
 
Bob Meissner  Welding Engineers