Good idea, I will try that if the problem occurs again. The issue vanished and hasn't reoccurred in the last few days.
I've been leaning toward a bad Ethernet cable or port on the MacBook Pro as a possible cause. If the problem happens again I will immediately switch to wireless and try to print. If it does still spew out garbage, I will try your suggestion.
An update: No problems printing at all in the last 3 weeks via wireless, so it appears to be a bad cable, bad Ethernet port on the MBP, or a bad port on the hub. Strange issue, but I may not troubleshoot it any further since it's working now.
