If you have replaced the toner in your Brother DCP7065DN, and the "Toner Life End" or "Replace Toner" message has not automatically reset, you may wish to follow the following procedure to reset it manually:
This procedure has been tested on the DCP-7065DN but may also work on other DCP models that take the TN2230 / TN2250 / TN450 toner.
Users have confirmed that the procedure works on: HL-2280DW, DCP-7040, DCP-7055 / HL2280DW, DCP7040, DCP7055