Epson has filed more lawsuits against companies making or selling third-party ink cartridges that it believes infringe upon its intellectual patents.

The company filed a complaint last week with the US International Trade Commission against 24 companies that manufacture, import, or distribute aftermarket ink cartridges for sale in the US, the Japanese company said yesterday. The complaint seeks to ban the companies from importing or selling the cartridges in question in the US. In conjunction with this case the company also filed a lawsuit in the US District Court in Portland against the same companies seeking damages for the alleged intellectual property infringement.

Epson has also kicked off a patent-infringement case in the High Court on this side of the Atlantic against Medea, it said today. As in the US cases, Epson is alleging that ink cartridges imported by Medea, which are sold in the UK under the Inkrite Photo Plus brand, infringe upon its patents.

The case against the UK company was brought after it began promoting a spongeless valve design in its cartridges as being "radically different and unique". In fact, the design is similar to a patented Epson technology and the lawsuit was brought "to set the record straight", Epson said in a statement.

Epson fought similar battles in 2005.

In April it filed lawsuits in the same Portland court against Armor, of Nantes, France and Multi-Union Trading of Hong Kong. The latter ended with a settlement that saw 75 of Multi-Union's cartridge models barred from being imported and sold in the US.

In June the UK's Environmental Business Products said it had stopped importing and supplying Epson-compatible printer cartridges as a result of an out-of-court settlement between it and the Japanese company and in October another British company, CybaHouse, agreed to stop selling and importing Epson-compatible cartridges as part of a settlement with Epson.