HP, who has a substantial amount of profits coming from printer suppliers, has accused two companies that sell refilled ink cartridges of patent infringement. The company, however, did not denote its intention to block the refill business altogether.

?On Friday, HP sued InkCycle in U.S. District Court for the western district of Wisconsin, alleging that the company's ink violates three HP patents. And on Monday, HP sued RhinoTek in U.S. District Court for the northern district of California, accusing RhinoTek of false advertising by using packaging that indicates its refilled HP printer cartridges are new,?CNET News.com reports.

Analysts believe that refilled cartridges account for 10% - 15% of the market.

?We still believe it's the customer's choice,?said HP spokeswoman Monica Sarkar, adding that HP believes its products have better quality and reliability.

• CNET News.com: HP Sues Firms that Refill Ink Cartridges.