DENVER – In-N-Out Burger is suing Denver-based Smashburger for copyright infringement and other trademark-related claims over its use of the term “Triple Double” to describe and advertise one of its cheeseburgers.

The California-based burger chain filed the claim Monday in U.S. Central District Court of California.

In the lawsuit, In-N-Out claims that Smashburger knowingly started using the moniker for its new burger in July despite opposition being raised by In-N-Out about trademark filings made by Smashburger late last year.

In-N-Out has long-existing national and state of California trademarks on the “Double-Double, Triple Triple, and Quad Quad” burgers, and some similar trademarks like “2 x 2” and “3 x 3”.

The chain claims that Smashburger—which was founded in 2007 and has since opened more than 300 franchises nationwide, including 36 in California—is actively harming In-N-Out’s reputation by selling the “Triple Double” burger and “diluting” In-N-Out’s trademarks.

In-N-Out has a “Not-So-Secret Menu” that customers can use to customize their burgers and which can, according to the lawsuit, result in “Triple Double” or “3 x 2” orders.

In-N-Out claims that after Smashburger filed its trademark claims for its burger late last year, In-N-Out filed a notice of opposition with the Trademark Trial and Appeal Board in June 2.

But after that, according to the suit, Smashburger then started using the “Triple Double” term.

“In-N-Out is informed and believes…that Smashburger…chose to adopt and use the Triple Double and Smashburger Triple Double marks to trade on the goodwill associated with In-N-Out’s Registered Marks,” the lawsuit says.

It goes on to say that by using the “Triple Double” moniker, Smashburger “creates a likelihood of consumer confusion because actual and prospective customers are likely to believe that In-N-Out has approved or licensed Smashburger’s use of its marks, or that In-N-Out is somehow affiliated or connected with Smasburger or its services.”

“Smasburger’s use of In-N-Out’s famous trademarks implies that the quality of the goods and services offered by Smashburger is the same as that of In-N-Out,” it says.

The lawsuit claims that Smashburger’s use of “Triple Double” causes In-N-Out’s customers “confusion, mistake or deception” and that it has suffered damages and “irreparable injuries to its reputation and goodwill.”

Among the claims In-N-Out makes, it says that Smashburger has intentionally created unfair competition contrary to California law:

“The actions of Smashburger…were taken with substantial certainty that such acts would cause harm to In-N-Out, in conscious disregard for the rights of In-N-Out and by conduct that was done with malice and ill-will and intent to harm In-N-Out, such as to constitute oppression, fraud, malice, and despicable conduct…entitling In-N-Out to exemplary damages in an amount appropriate to punish and set an example of Smashburger.”

In-N-Out asks the federal judge to permanently enjoin Smasburger from using either of its “Triple Double” terms, as well as issue preliminary and permanent injunctions barring Smashburger’s use of the terms.

Among other things, In-N-Out is also seeking compensatory damages, and treble damages—which could triple the amount of compensatory damages awarded in the case, if there are any.

A Smashburger spokeswoman sent the following statement Tuesday afternoon:

Smashburger’s new Triple Double Burger, launched in June, was developed to celebrate the chain’s 10-year anniversary.

“We wanted to create the best cheeseburger for the next generation of burger lovers. With two Smashburger patties and three layers of melted cheese, we named it the Smashburger Triple Double, which has really resonated with consumers,” said Smashburger Co-Founder & Chief Executive Officer, Tom Ryan.

“Frankly, we are flattered by the attention In-N-Out has given our Smashburger Triple Double. To date, Smashburger’s Triple Double is posting double-digit traffic and sales increases for the 10-year-old Smashburger brand. The Triple Double burger is clearly popular with our customers and is not comparable to any In-N-Out menu offering,” added Ryan.

“We invite all burger lovers to taste the Smashburger Triple Double and decide for themselves.”