How to reset 'Inkbox Full' notice for printer BROTHER DCP-T720DW

Steps how to reset the inkbox full notice for Printer Brother DCP-T720DW Step 1: Power off then power on the printer Steps 2: Press &and Mono button then press 4x for the &up&untill Machine Err 4600 displays on the screen. Steps 3: Press arrow up until displays the number 8 then press &it should display the MAINTENANCE 8 on the screen. Steps 4: Press arrow up again until displays the number 0 then press &it should display the MAINTENANCE 80 on the screen. Steps 5: Press the &button until you find the &COUNT&on the screen then press &button it should display the PURGE counter on the screen. Steps 6: Enter the reset code &by pressing the &UP&button until the purge counter set to zeros.