IntelliFAX 4750E - Printer Busy
The printers memory may be full depending on the type of documents they are printing. The first and most simple step is to unplug the power cord from the back of the unit for 30 seconds, put your finger on the stop key while plugging the unit back up and continue holding the stop key until the time and date are back on the display of the Brother unit.
If that does not work unplug the USB cable from the PC. Unplug the power cord from the unit again. Put your finger on the menu key first and then plug the unit back up. You want to hold the menu key unit the until the LCD says maintanence and all the lights are flashing. Let the menu key go and press the number 82 and will give you an error code. If the error code is 00 then there are no errors. If there is an error code record it and contact brother or check a service manual if you have one. Most laser products all have the same error codes with Brother.
To reset the unit press stop and then 91, this will reset the unit and all faxes or print jobs will be lost. This should clear the issue.