A toner cartridge, also called laser toner, is the consumable component of a laser printer. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image on the paper. The toner is transferred to paper via an electrostatically charged drum unit, and fused onto the paper by heated rollers during the printing process.

Compatible — also known as "generic" or "alternative brand" are cartridges are manufactured from scratch, they are not used cartridges that have been refilled or re-manufactured. They are produced by third party companies and sold under different brand names. Often compatible cartridges may vary slightly in look, design and page yield to their genuine counterparts due to certain patents that restrict the exact copying of designs. Although these generic cartridges may be less reliable, they may be a cost-effective alternative to the genuine article. They can also be manufactured to contain more ink than the OEM versions, depending on the design of the cartridge itself.