Shops and restaurants in the US have joined a coalition against the abuse of patents. The group says patent trolls are now targeting businesses that aren’t even involved in the relevant technologies.

The Stop Bad Patents campaign, run by a group called the Internet Association, gives the example of somebody claiming to have a patent on JPEG files demanding money from several major national retailers who used images in promotional e-mails and on their websites.

The campaign now has the formal support of the Food Marketing Institute, the National Restaurant Association and the National Retail Federation. It’s now running print (extract pictured) and radio ads in several states asking for Congress to take action to crack down on patent trolling. The campaign website has a page that produces links to the Twitter and Facebook accounts and website contact pages for the Congress members in your zip code.

According to the campaign, it’s not just the high-profile multi-million dollar claims that are a problem. Instead it points to claims for smaller amounts, for example $100,000, that are high enough to be lucrative and expensive, but low enough that a big company may decide it’s easier to pay up than risk the costs of defending the claim in court.

NPR notes that a Government Audit Office report published last month found that around 20 percent of the 500 lawsuits analyzed in a study had been brought by patent trolls — officially known as nonpracticing entities, meaning companies that own patent claims but don’t produce any goods or services. That report noted that contributing factors to the problem include software-related patents being too broad, and courts awarding large sums even in cases where the patented technology played only a small role in the product.

There’s still a debate about whether its possible to create legislation that reduces patent trolling without hurting “genuine” patent holders.