Brother laser printers, fax machines and multifunctions all use a toner reclaim system. That means the used or left over toner (along with paper dust and debri) is recycled into the new toner cartridge supply. There is no waste section for the leftover toner and debri. This design is efficient however their are some short falls that you need to address. The toner cartridge supply is slowly contaminated with debri and dust that will send the cartridge down prematurely if your not using a good quality paper.
In addition, Brother Drum Units (ie DR-400, DR-500, DR-510, etc...) are expensive and suffer from the same premature failure problems. There is a charging brush and transfer roller inside the front top inside of the drum that drags on the drum surface to charge and discharge it properly for toner transfer. If you use poor quality the built up paper dust and debri interferes with this system and ultimately prevents it from working prperly. Here's a photo of a newer drum that failed due to the use of poor paper. Note the paper dust embedded in the transfer roller (top), caught up in the charge brush (center) and actually laying on the drum (bottom).
Here's a closeup of the charge brush so you can see the problem better below.
Below is the damage that bad paper caused. This DR-520 drum pictured is rated for 25,000 pages but due to low quality paper lasted just over 7,000. This was caused by a "Store Brand" paper.
Here below is a photo of the inside of a brother toner cartridge contaminated with paper dust and debri due to la ow quality super store brand paper. Note all the white paper dust in the toner.
To get the full yield from your Brother supplies, simply use GOOD QUALITY PAPER. STAY AWAY FROM STORE BRAND PAPERS as they go out on low price bid rather than to meet a tight quality standard. I would recommend a HP Brand paper as it's an "ALWAYS KNOWN GOOD" paper. The cheapest on the HP branded papers is HP Office and it works well.
Hope this has helped you understand the importance of using good quality paper in your brother machines. If you found this helpful, please rate it with a FIXYA as significant time and effort was used to help you.
Thanks and Happy Printing