If you haven't gotten a Pi up and running before, there are instructions all over the place, here are some from raspberrypi.org.

There are also a bunch of online tutorials on how to set up a Raspberry Pi as a wireless print server.  I used these:

• PiMyLifeUp Raspberry Pi Print Server
• CircuitDigest Raspberry Pi Print Server

Read through them first to get an idea of the whole process.  Go ahead and install CUPS and SAMBA and make all the config file changes you need to.  Do all of that BEFORE installing the printer and printer drivers on CUPS.  More on that in the next step.

When you get to the part about installing the printer drivers on CUPS, that's where the fun begins.  Since the Munbyn ITPP941 is an off-brand, I had a bit of trouble finding the proper drivers for the Pi.  Munbyn advertises support for Windows, Mac, Linux, and the Raspberrry Pi in particular, so I assumed their drivers would be easily accessible.  HA.  HA.  HA.  They ship a USB stick with the printer, but it only contains Mac and Windows drivers (and more about that Windows driver later).  All of the easily accessible links from their site are for direct downloads to the same.  Or are broken links.

After Bob knows what kind of google searching and link clicking around the Munbyn site I did, I finally found a link for their entire directory of driver downloads.  And there it was, in the "ITPP093+941+168+966+942" folder, The RPi Driver Installation Guide and the RPI install.run file.  I've attached them in the Files section so you don't have go through the same kind of digging hell I did.

The installation guide is graphical and good - just know that Step 0 is to   Then follow the rest of the instructions.  A few clarifications:

• Step 0 is to put the "RPI install.run" file on your Raspberry Pi desktop, and rename it install.run.  Then follow the command line instructions.
• When you get to installing it in CUPS, be sure to click "Share this Printer" checkbox.
• The driver you'll select is under a "Rollo" printer.  
• The stock size for shipping labels tends to be 100 x 150 mm.

Print a test page from CUPS, just to make sure that the setup on the Pi is all good.

Congratulations!  You're maybe almost halfway there.  Because now you have to tackle Windows and more printer drivers, and that's a doozy of a next step.

If you have Windows 10 Pro - skip to the next step!  That's right!  They're different!  Because Windows!

Note 11/16/2021: our Windows Home machine suddenly stopped seeing other network devices including the printer, we think after a Windows update on 11/11/2021.  We had to delete the existing printer and add it again according to the directions in the Windows Pro section below.  But hey, YMMV because Windows!  Try both.  Why not?  You're already buckled up and in for the ride.

OK.  Installation in Windows Home was the easier of the two.  The Pi and the printer just showed up and once I figured out the driver thing, it was all good.

Note - if you haven't installed SAMBA on your Raspberry Pi yet, stop and go back to the tutorials linked above (the PiMyLifeUp one is the best) and do that.

Now, you might think - maaaaaybe if I just go to Printers, it'll show up and I can just click on it and BAM!  All good!  Well, you'd be wrong.  It'll show up in your printer list (if you've done everything right so far) as "<PrinterName> on <RaspberryPiName>".  And you'll click it, and after a spinning circle and a few seconds, you'll get this fantastic Windows 10 blue popup that - no shit - says "That didn't work".  Yup.  Welcome to the future!

If you haven't previously plugged your printer directly into this computer and printed to it, do that now.  Follow whatever the manufacturer's Windows driver installation instructions are for your printer.  If you're lucky, it'll just automatically happen when you plug the printer in.  If not, you'll have to either select the driver from a list or choose it from a file location.  There are plenty of other tutorials on that.  For the Munbyn, I can't remember what the process was when I first hooked it up.  It may have auto-installed, or I may have had to run the .exe file on the USB stick.  I've attached the exe in the Files section here as well.  Be sure to configure all your printer and paper settings, and print a test page.

Now we're continuing with the Windows setup detailed in the PiMyLifeUp tutorial - see it for screenshots.  

1. On your Windows 10 Home machine, go to Networks and you should see your Raspberry Pi listed.
2. Double click it, and you should see your printer listed.
3. Double click it, and you'll get a sad Windows popup saying No driver found.
4. Clikc OK.
5. If you're lucky, you'll see a Munbyn listing and be able to select the actual driver used for the printer.  Click it and it will install.  Print a test page.  Change the paper and printing preferences if you need to - those are under Settings - > Devices -> Printers and Scanners -> <PrinterName> -> Manage -> Printer properties.  You're done!
6. If you're not lucky (like me), Windows decided to install some generic-ass "Label Printer" driver for the Munbyn and your only choices will be "Generic" and "Microsoft".  I also tried searching for a specific Munbyn one both on my system and on the internet, but the only file type you're able to point the installer to is an .inf, so that nice .exe auto-installer that Munbyn provides is useless.  I searched high and low for a Munbyn .inf and never found one.  What I did, which ended up working, was: selected "Generic" and "Generic IBM Graphics 9pin".  It will successfully install your printer in your printer list.  Then go to your printer list (Settings -> Devices -> Printers and Scanners), click on your printer, click "Manage", then click "Printer Properties" in the sidebar.  In that dialog, under one of the tabs, you should be able to set the printer driver to "Label Printer".  Then click apply, and the dialogs will change to show all the proper settings specific to the label printer.  
7. Select the paper size and everything you did before for your label size (100 x 150 mm for shipping labels, I had to change from "Continuous" to something like "Labels with space between them").  Print a test page.  You're done!

Oh, what, you've successfully installed your printer on a Windows 10 Home machine and think it's just gonna be the same thing for Windows 10 Pro?  HA!  Think again.  Microsoft hates you and wants you to suffer.

First, you may notice that your machine doesn't even see the damned Pi under Networks.  What the hell, right?  Windows 10 Home machine sees it, it's obviously working.  Well, I dug around A LOT and finally came across this gem of a forum post.  Thank you helpful people, thank you.  I did both of the things the post suggested, don't know which worked.  I don't even know if these are ultimately necessary, because as you'll see in a bit, I ended up using a different method.  But I dunno, I figure that the darned Pi should at least show up in the places you'd think to look for it, say, if you wanted to also share some files later on.  Without further ado:

First thing is that maybe your security-conscious Windows Pro machine doesn't want to connect to some other rando machine as a passwordless guest.

• Run good old regedit and go to HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\AllowInsecureGuestAuth
• Note that HKLM is short for H_KEY_LOCAL_MACHINE
• You might think that  \LanmanWorkstation\ is the name of some guy on the internet's computer and be tempted to look for your own computer name in this folder.  Spoiler alert: LanmanWorkstation is what that folder is actually called.
• Add a DWORD value of 00000001.

Second thing is that maybe lack of SMB 1.0 support is the issue.

• Run optionalfeatures.exe from the search bar to get to the Turn Windows Features On/Off dialog.
• Scroll down and expand Print and Document Services
• Make sure Internet Printing Client is checked.  I think I also checked LPD and LPR at this point for shits and giggles because I thought I would have to try those services later.  Whatever.  I don't think those are needed.
• Keep scrolling and check SMB 1.0/CIFS File Sharing Support
• Click OK
• Restart your computer

Voila!  Your Raspberry Pi should now freaking show up in Networks.

Now, maybe you can follow the steps for the previous Windows 10 Home section.  It's worth a shot.

Oh what, after selecting the driver, you get an error that you can't connect to the printer?  HEH HEH.  I'm totally laughing with you, really.  Ok, you can do this, it's the final push.  Follow the instructions in the CircuitDigest tutorial and see their screenshots.

1. Go to the CUPS web interface, which you should be able to access from this Windows computer.  Go to Administration, Manage Printers, and make a note of what the printer name is in the list.
2. Go to your Printers list in Windows and click Add a Printer.  Curse the powers that be that the perfectly fine looking printer that appears in the list doesn't actually let you add the printer.  WHY GOD WHY?!
3. Click "The printer that I want isnt' listed"
4. Click the dot for "Select a shared printer by name" and type in http://(the url of your printer which should end in :631)/printers/(the printer name you took note of in step 1)
5. Then click next or whatever, and voila!  The printer should install.
6. Print a test page.  Rejoice.

You deserve it!