Printer manufacturers have an ongoing battle with third party companies that are responsible for creating inkjet refill cartridges. Inkjet refill cartridges are those products not made by an original printer manufacturer, but by an outside source. The inkjet refill cartridges are designed to be compatible with the printer manufacturer's equipment and are often much cheaper than the retail prices offered by an original manufacturer.
This ongoing tug-of-war for the market share of ink is for good reason. Printer manufacturers earn much of their profits from customers who need to replace ink. According to the SF Gate, HP engaged in a lawsuit with two different third party companies in 2005 - Inkcycle and Rhinotek. HP claimed Inkcycle violated three HP patents and Rhinotek engaged in false advertising that indicated new packaging. However, it is worth noting that HP falls short of fighting the use of inkjet refill cartridges completely and maintains that the consumer has a right to choose inkjet refill cartridges or refill a legally purchased cartridge.