New printers are sold with starter cartridges that do not have a reset gear and, therefore, cannot be reset. There are two options if you want to refill a starter cartridge. You can either purchase a reset gear separately or you can access your printer's reset menu. However, the reset menu can only be used once per cartridge. See how to access the reset menu on your Brother printer. 

You'll need one reset gear for each cartridge that requires it. You can also purchase this reset gear in a set of 4.

Each reset gear includes with the following:

• The reset gear
• Easy and detailed instructions