Printer Over Network Constantly Dropping Connection

I have a wireless network running a Win 10 and a Win XP machine through a DLink router, with an HP printer connected via USB to the XP machine. I set it up using the Add Printer wizard to share the printer over the network, which initially worked. The problem is that the printer will constantly disappear from the Win 10 machine ("client" connection), and I have to run the Print Share wizard to fix it. As I stated above I added it using the wizard, and just used the host name from the list of available printers. I spoke to a friend of mine who said that if I add it using the IP address of the "server" it will be much more reliable. I tried to do that also, but it asked me for a network username and password, which was never established. I tried using the Windows login info, but that didn't work. So my first question is, why is the connection dumping all the time? And my second, is adding via IP better? And if so, why is it asking for a password. Thanks.