Have you ever thought that the running cost of keeping your printer topped up with ink seems a bit expensive? Well, you are not alone, recent tests have concluded that some branded printer inks are among the world's most expensive liquids, with a price per ounce outpacing brands like Dom Perignon Champagne and Chanel Perfume. If you were to fill your car petrol tank with the same ink, it would cost you around £40,000, makes unleaded look rather cheap!

For years, printer manufacturers have coupled low-priced inkjet printers to high-priced disposable ink cartridges, making more profit on the cartridges than the printers. HP's Imaging and Printing group made sales of $6.1bn and posted a profit of $932m in the first quarter of 2004. However, independent businesses have been manufacturing, recycling or refilling ink and toner cartridges and selling to consumers for much lower prices. Recently it has been alleged that technology, mostly in the form of chips on the cartridges are being used to prevent or restrict refills and that the cartridges read as being empty, way before they have actually run out of ink.

HP is facing a class action suit in the US from a woman who claims the vendor's printer cartridges stop working at a predetermined date, rather than when they run out of ink.

In 2003 the Dutch Consumer Association, Consumentenbond, made similar allegations against Epson. Consumentenbond advised its members not to buy Epson inkjet cartridge printers because it claimed Epson's cartridges contained a chip which stopped them working even when they had ink left in them. The chip doesn't indicate the amount of ink left in the cartridge, the association claims, but stops after a number of print runs, even when there is enough ink available for more prints. Consumentenbond later withdrew its claims.

The British Consumer Association's Which? magazine printed similar accusations, advising consumers to steer clear of brand name printer cartridges and pick cheaper alternatives instead.

Epson denies any wrongdoing, saying that the chip is preventing users from running out of ink and said the remaining ink was required to ensure proper printing. Epson also questions the test methods being used. In the US, Epson has filed patent infringement lawsuits against two companies that manufacture replacement cartridges for its printers. Epson claims that certain cartridges made by the two companies infringe on several of its cartridge-related patents. The lawsuits are not an effort to stamp out the third-party cartridge market and are aimed only at companies that have infringed Epson's patents, says Alastair Bourne, a spokesperson for Seiko Epson in Tokyo.

Meanwhile, the Lexmark DMCA case (where they sued another company for figuring out a way to allow non-Lexmark cartridges to work in their printers) continues to move forward with the Electronic Frontier Foundation filing a brief against Lexmark.

Last year, several printer manufacturers, including HP and Lexmark, tried to stop the European Union passing regulation that would outlaw the use of these chips, but their pleas were largely ignored. The anger over printer company tactics may lead to a more formal investigation at some point to investigate these practices, already, in the UK the Office of Fair Trading is looking into the issue. By 2006 the use of chips to prevent or restrict refills will be strictly forbidden under European law.

With large demand for low cost printer cartridges, several online suppliers have emerged. One of these is Mouse2House. They advise, “Over years of experience we feel that on most occasions the original branded cartridge specified for your printer will give you the best prints, however this can be quite expensive. If the manufacturers charged more reasonable prices, the market would be of less interest to counterfeiters and consumers would have less interest to find marginally cheaper products. There would not be any reason to use questionable tactics and huge amounts of money would not have to be wasted on developing unnecessary technology. As the market stands today, there is understandably a huge demand for low cost printer consumables and a big manufacturing industry exists to supply alternative products, some very good quality and others very poor.