Brother HL-1260 - Manual (Page 401)

USER’S GUIDE
7–14
3. Rock the cartridge gently several times at a 45° angle.
This distributes the toner evenly inside the cartridge.
45°
45°
Fig. 7-10 Distributing the Toner Evenly
4. Install the toner cartridge and close the top cover of the printer.
5. Print out several pages.
If you are still not satisfied with the printout, replace the toner cartridge
with a new one.