I agree with Lost_luggage34 -
The printer has a built-in JetDirect card (print server).
What you need to do is use the JetExpress (or whatever they are calling it now) software / web interface provided to configure the printer's network interface for your network.
Having said that, I have come across "wireless-enabled" printers that actually require you to connect them to your PC first via USB to configure the wifi network card, before subsequently deploying them as wireless devices.
SD