Lexmark Black Toner Cartridge 20K pages - 51B2X00 Lexmark Return Programme cartridges are patented print cartridges sold at a discount in exchange for the customer's agreement to the licence requirement that the cartridges will be used only once and returned only to Lexmark for remanufacturing or recycling. These patented cartridges are licensed for single use only and will stop working after delivering a fixed amount of ink and/or toner. Ink and/or toner may remain in the cartridge when replacement is required. Replacement cartridges sold without these restrictions are also available.