According to a HP technical representative the standard spooler for HP-UX 10.xx does not support port 9100. It only supports port 515 (LPD)
In order to get the spooler to use port 9100 you must install HP's JetAdmin Utility for UNIX.
This document is based on JetAdmin v D.06.21

Make sure you are login in as root.

The first step is to see if you have the spooler running. I have been having intermittent problems with grep on my HP machine (no I haven't checked for updates yet, there are only so many hours in the day and I am not going to give up my afternoon nap ;-) ) so I recommend piping 'ps -ef' through 'more' to check if the spooler is running.
open a terminal window and run:
#ps -ef |more
look through the output and somewhere, probably closer to the end you will find a line that ends in
/usr/sbin/lpsched or just lpsched
If you do, this is cool, the standard spooler is running. If you do not have this daemon running try to get the admin to set it up. If there are problems you can contact me and I will _try_ to help.

The next step is to see if JetAdmin is running. Do the same as before,
ps -ef |more
and look for a line ending in
/opt/hpnp/bin/hpnpd (well look for hpnpd, the path is what my version is using)
If it is there, Yahoo, you are ready to add the printer. See below.
If it is not there you need to add it.
JetAdmin is(was?) a free download from HP and I downloaded the HP-UX version on June 5, 2001

If you have problems installing it you can contact me and I will _try_ to help. (don't hold your breath I don't know what I'm doing)

Once we have all our needed services up and running we need to add the printer. There are many ways to do this. I will explain what I hope is the easiest. (You never know in UNIX)

We'll start by stealing info from the normal HP-UX page
1. Login as root.
2. Run Sam. HP's System Administration Manager. On my machine running CDE, I open the Application Manager, then the System_Admin group, then double click on Sam.
3. Once Sam is running, open the group Printers and Plotters.
4. Then open the group LP Spooler.
5. Now run printers and plotters.

6. Click on the Actions menu and then on Add Networked-based printer/ploter >add printer/plotter connected to HP JetDirect...
7. Read the note (not necessary): see we didn't need to run SAM, but hey, it's a GUI ;-) We don't need to 'create printer configuration in BOOTP/TFTP database. click ok.
8. A SAM terminal window will open with our configuration utility. we need to "add printer to local spooler" so type '3' and hit <enter>
9. If you have the printer registered in a name/address resolution enter that name here. If not enter the IP address to the printer and hit <enter>
10. You will get an error saying:

!! no response from <what you typed above>!!
...(trying to ping <same as above>)
The HP JetAdmin utility can ping the device. The problem may be:
<list of stuff>
do you want to continue?

This is OK. We are not using a JetDirect box.
press 'y' and hit <enter>

11. You now get three choices. Select '2. ignore it and continue the process' and hit <enter>
12. You get a small warning, which you might miss, (you can ignore it) and (wait for it) a list of printers. Hit the space bar to continue through the list.
The HP tech recommended #53 "To Select dumbplot model script for printer" This is a generic script.
if you know of a better one or you just want to play around till you find something better, have fun and please email me the results.
At the prompt type in the number you selected and hit <enter>.

13. Now it is going to ask "is the printer connected to:" Choose 4)other and hit <enter>
14. You now get a list of configurable parameters: At this point I pressed 1 to rename the queue.
15. You now have a list of currently used names. Enter the name you want to use and hit <enter>. This is for the local queue(what the printer is called on the local machine)
16. Now you are back at the configurable options screen. press 0 [zero] to configure and hit <enter>
17. You will get a measage about the spooler and do you want to contine. If it is safe to continue press y and hit <enter>

18. You get some more info (read it, no really) and at the bottom of the page the measage "Standard input: END"
press q or space bar to go back to the main menu.
19. Press q <enter> to exit the utility,when prompted hit <enter> again to go back to Sam.
20. You should be done. exit your way out of sam and test the setup.

good luck