Brother MFC-7420 Prints from iMac, not from Macbook Pro using Airport Extreme

I have a Brother MFC-7420 printer. Up ntil a few days ago, I coiuld print from my Macbook Pro, as the Systems Pref. in the iMac allowed for everyone to print. Now I get the message "Printer Off Line," when the printer icon pops out of the dock in my attempt to print from the MacBook Pro. I use wired with the iMac, wireless with MBP, but it printed fine with the Extreme. Any answers, appreciated.