Why wont brother mfc-420cn feed paper to print?

SOURCE: Brother Mfc 420cn says machine error AF

Open the small cover that hides the scanner flat cable. It has to be reconnected to the main pcb.

SOURCE: my brother mfc 420cn printer won't print

i reset the printer to the original factory settings, and now it works. thanks for your concern and help, richard

SOURCE: Double prints or Text shadow printing by MFC 420CN

yes. you have to run the alignment feature. press ink - set - arrow-down til alignment. After alignment test print read the paper and choose the right setting by nr.

SOURCE: clean brother encoder strip

The encoder strip is barely visible thru the top in front of the printhead, if you can see it without taking all apart, you use a Q-tip just damp with water and wipe each side as far as you can reach.

SOURCE: I have a brother mfc-420cn. I am getting a unable to clean messa

Do you mean "unable to clean"?If it this follow this instruction.
Unplug the printer from power cord.Press and hold the "menu" button, then plug the device.You'll see on the LCD screen a "machine error" code.If this code is 40,41 or 4F the print head is defective.If the error is 50 or 51 there is error in Purge unit and printer require service.If the error is 46 the waste ink tank is full.Follow this:Enter 80, then scroll down with the arrow down (round) key. You'll find an entry listed as purge count. If numberis over 6000, enter 2 7 8 3.This will reset the purge count value. Then restart the printer, hopefully without the annoying cannot clean message.