Seiko-Epson's battle at the US International Trade Commission to have 24 companies banned from the import of Epson-compatible ink cartridges has moved a step closer to conclusion.

On 30 March ITC judge Paul Luckern issued an initial determination that the ink cartridges in question do infringe upon Epson's patents, the Japanese printer-maker said on Thursday. He also recommended the companies and others are barred from importing and selling the cartridges in the US, Epson said.

The company and two of its subsidiaries filed a complaint with the ITC in February 2006 against the 24 US, South Korean, German, Hong Kong and Chinese companies alleging infringement against 11 Epson patents.

Prior to the start of the case, some companies settled with either Epson or the ITC and agreed to stop importing the cartridges, however others either failed to respond or claimed their right to fight Epson's assertions in front of the ITC, said Kenkichi Shibata, a spokesman for Epson in Japan.

In January a hearing was held at which several companies – Dataproducts USA, a division of Clover Technologies Group, Ninestar Technology, Zhuhai Gree Magneto-Electric, and their affiliated companies – presented arguments to Judge Luckern, said Epson. The judge found that more than 750 models of cartridges imported by the defending and defaulting respondents infringed on at least one of the 11 patents in question.

The ITC will study the intial determination from the judge and make a final determination on 30 July.

At the same time as it made its ITC complaint Epson also filed a civil lawsuit against the same companies in the US District Court in Portland seeking damages for the alleged intellectual property infringement. The civil case in the Portland court is still continuing against some of the companies, Shibata said.

The actions were part of an ongoing campaign by Epson to stop the sale of third-party ink cartridges that infringe upon its patents.

Epson has had a number of successes in its fight. In June last year a court in Taiwan barred a local manufacturer of continuous ink supply systems from producing models for Seiko Epson printers after receiving a petition from the Japanese company. A month earlier Epson succeeded in getting four German online retailers of printer ink cartridges to stop selling a number of third-party ink cartridges designed for use in Epson printers.