After changing a DR1050 drum unit in a Brother HL-1112, the printer’s page count needs to be reset. This will turn off the drum warning light on the printer.
Simply open the front cover, and press the power button four times, then close the front cover.
Youtube Video: Change Toner Cartridge
The printer normally requires the toner cartridge to be changed before all of the toner has been used. This is to ensure the quality of the print stays high. Putting the printer in to “Continue Mode” will use all of the remaining toner in cartridge. The print will eventually start to fade, and quality will become poor.