Which printer driver?

What makes the grass grow?

Do the full install. The driver has nothing to do with your modem, though. It's your computer, and the printer. The reason I say full install is that there may be components or software that require parts of the full package in order to function, and that may not be apparent at the moment.

Is this Xfinity modem a modem/router combo unit? If so, get a new router at a minimum, disable the modem's router, or put it in pass through mode, and set your network up with your new router. Make sure the computers are setup for a network printer. Ideally I would replace that modem/router combo unit with separate devices, i.e. a stand alone modem, and a stand alone router. You'll also save on the Xfinity modem/router monthly rental fee.

Combo units are notably inferior to a separate modem and router package (particularly the wifi radios), but the big difference is your ISP can no longer charge you a monthly fee for "renting/leasing" their combo unit. Also, something else about a combo unit is if either half fails, your network is down, and you have no internet connectivity. I would also suspect that your computer's printer setup is looking for a network printer that has a slightly different configuration. I'd delete the printer in your computer and then reinstall it.