In VBA, how do I use the "Open" command to print to a TCP/IP printer?

I have a Zebra S4M network printer (Ethernet connection) on a Windows Server 2003 network where the users are running an Access 2007 application.
Because of problems with Access Reports and barcode fonts, I am having to send Zebra Programming Language (ZPL) commands directly to the printer to print some barcode labels.
In VBA I am using an "Open strPrinterName For Output As #intFreeFile" instruction to open the link to the printer, but am having a problem with the "strPrinterName" when the printer is a "TCP/IP" device with its own IP address.
I have tried the full printer name, the port name and the IP address but none of these have worked.
I have managed to get it to work by making the printer "shared" on a particular PC and used the syntax "\\PCName\ShareName", but presumably that PC needs to be switched on for this to work and this seems to defeat the purpose of having a truly networked printer.

The Zebra S4M printer has what they call a "Zebra Printserver" installed but I have not been able to see the name of that printserver anywhere?

Can anyone help with the naming of this printer for my VBA code so that I am not dependent on a "share" on a particular PC?

Many thanks.