Nippon Paper unit sues over toilet roll patent

A Japanese toilet paper maker is suing a rival over a patent used to make rolls that are three times longer.

The longer-lasting rolls have become popular in Japan because they take up less storage space.

Nippon Paper Crecia had been selling them for six years as of April, when rival Daio Paper introduced rolls that are 3.2 times longer than conventional ones.

Nippon Paper Crecia filed a patent infringement suit against Daio Paper with the Tokyo District Court on Tuesday.

The subsidiary of a major paper producer is seeking an injunction against Daio's production and sale of long toilet paper rolls. Nippon Paper Crecia is also seeking 33 million yen, or about 230 thousand dollars, in damages.

The company is accusing Daio Paper of infringing on patents for manufacturing technology that keeps toilet paper soft while rolling it longer than conventional types.

Demand for the longer rolls has been rising and the product now accounts for 35 percent of toilet paper sales at Nippon Paper Crecia and 40 percent at Daio Paper.

Daio Paper declined to comment about the lawsuit, saying it had yet to receive a written complaint.