A federal court judge has rejected Boston founder Tom Scholz’s efforts to block former singer Fran Cosmo and his guitarist son, Anthony, from referring to themselves as “former members” of Boston.

Fran Cosmo was the lead singer on Boston’s 1994 “Walk On” album and toured with the band through 2004. His son was a guitarist and songwriter for the band from 1999 until 2004.

Scholz had sued the Cosmos in federal court in Washington state, alleging that they had violated his trademarks in the band name Boston by referencing their past affiliation with the band. As part of that lawsuit, Scholz asked the court for an injunction seeking to dictate how the Cosmos could refer to their former affiliation with Boston.

In a nine-page decision issued yesterday rejecting Scholz’s request, federal judge James Robart found that Scholz had “failed to establish that he is likely to succeed on the merits, that he is likely to suffer irreparable harm in the absence of preliminary relief, that the balance of equities tips in his favor or that an injunction is in the public interest.”

Over the years, Scholz has been involved in numerous lawsuits against former members of the band Boston as well as managers and other persons affiliated with the band. In 2006, he filed his first suit against Anthony Cosmo.

Most recently, Scholz sued Barry Goudreau, one of the original five members of the band, in Massachusetts federal court in connection with Goudreau’s referencing of his former affiliation with Boston. This is at least the third such lawsuit that he has filed against Goudreau.

In a ruling several months ago, Superior Court Judge Frances McIntyre awarded the Boston Herald $132,000 in court costs in defending itself from a libel claim brought by Scholz, stating that the “threat of expensive litigation could put litigious persons of public interest beyond media commentators because of the feared expense.”