PORTLAND – L.L. Bean filed lawsuits Monday against four companies it alleges used pop-up ads that appeared when some customers visit its Web site to infringe upon its trademark rights.

By creating ads that appear when Internet users visit L.L. Bean’s Web site, retailers Nordstrom, J.C. Penney, Atkins and Gevalia have traded on the company’s name, said Mary Lou Kelley, vice president for E-commerce at L.L. Bean.

“These advertisers are illegally poaching on L.L. Bean’s trademark,” Kelley said. “Using our trademarked name as a trigger to which you want to serve your ads causes customer confusion and crosses the line into trademark infringement.”

The retailers named in the lawsuits contracted with software company Claria Corp., which creates programs to track online habits, Kelley said. So-called “spyware” programs then create windows to display specific advertisements when a Web browser visits certain sites.

The lawsuit was filed in District Court in Portland.

Company officials for Nordstrom and Atkins declined to comment. A spokeswoman for Gevalia also would not comment until the company had seen the lawsuit.

Kelley said many consumers unwittingly install “spyware” on their computers when they download games or other programs from the Web.

“This is such a parasitic practice that consumers hate,” Kelley said. “We’re trying to get advertisers to stop serving pop-up ads on L.L. Bean’s Web site which annoy and divert our customers.”

In this case, Kelley said, customers’ interests are closely aligned with those of L.L. Bean, which each year sells hundreds of millions of dollars’ worth of merchandise on its Web site.

“Not only are they illegal, they’re very damaging to the investment we’ve made in our customer relationship,” Kelley said.

The only legitimate windows that would pop up on the company’s Web site would be one-question customer surveys, she said.