We recommend using genuine Brother drum units and toner cartridges. Each Brother laser printer is designed to work at a pre-set temperature that is matched exactly to each of our individual toner formulations. Each Brother component is designed to work with other Brother components to ensure quality and reliability. Although not all non-genuine supplies may cause quality issues, it is possible that some may adversely affect print quality or cause the machine to malfunction. The Brother limited warranty does not apply to any problem or damage caused by the use of third party drum units, toner cartridges, or toner.