Makers and resellers of third-party inkjet printer cartridges and refills polled at the CeBit show in Germany this weekend have criticised Epson for hitting them with lawsuits to protect its lucrative consumables business.

Japan's Epson, the world's number-two printer maker, filed complaints against 25 companies in the US and UK in February seeking to bar the manufacture, import and distribution of 'aftermarket' ink cartridges in those countries.

Aftermarket cartridges typically cost much less than official cartridges and threaten the printer maker's business model, which relies on selling a low-cost printer and making profits from future sales of ink.

"It's stealing money from customers. It gives them a free printer and then steal their money," said Brian Suh, marketing director of South Korea's EC World, which makes cartridge refill kits.

Suh said he thinks printer makers have become steadily greedier over the past few years and claims consumers are being treated unfairly. However, that view wasn't shared by all at CeBit.

"We are okay with what Epson is doing," said Richard Keller, manager of technical engineering at 3T Supplies of Switzerland. The company, which trades under the Peach name, develops compatible cartridges in Switzerland and manufactures them in the Czech Republic.

"Low-quality copies are not good because the whole price system collapses and it hurts the industry," he said. "But the way it [Epson] is doing it is very aggressive."

Epson fought similar battles successfully in 2005. It reached settlements with Multi-Union Trading of Hong Kong and the UK's Environmental Business Products and CybaHouse that saw all three companies stop importing and selling Epson-compatible cartridges in the US and UK markets.

The cases publicised by Seiko Epson to date have ended with out-of-court settlements so the industry remains unsure exactly where the line between patent infringement and innovation lies.

"The whole situation with Epson, the patent issue... we have to be careful," said Keller. "We believe our products don't infringe its patents. We have our own patents."

The lack of a clear legal ruling is what's enabling Epson to go after small companies, said Udo Rossner, head of sales at JR Inkjet Deutschland GmbH.

"As long as there is not a court case it can go around shouting because it knows tiny little companies can't go to court," he said. "If all the manufacturers got together and defended it as one it would be a big problem [for Epson]."

He believes Epson will never be able to completely control the market, especially because of its international nature, but thinks it might be easier to control the market through legal means in the US than in Europe.

"In the US it's easy, because corporations have more rights than consumers," he said. "But in continental Europe the consumer has damn hard rights. If they lose one case, they lose it all."