Dell C2660dn Color Laser Printer - Manual (Page 274)

Installing a Toner Cartridge
1 Unpack a new toner cartridge of the desired color.
2 Shake the new toner cartridge five or six times to distribute the toner evenly.
3 Insert the toner cartridge into the associated cartridge slot, and then push until it stops.
4 Close the front cover.
Maintaining Your Printer 272