The CEO of the embattled data storage company Imation said Friday that he will resign from the company in September.

Shareholders of the former 3M spinoff voted two months ago to oust CEO Mark Lucas from the company's board. In a letter filed with regulators Friday, Lucas said that his removal on May 20 constituted "good ­reason" for him to leave the company under the terms of his employment.

Under a "change in control" agreement he signed with the company in November, Lucas appears eligible to receive $4.8 million in severance.

The filing with the Securities and Exchange Commission said Lucas and Imation's board started a CEO succession planning process in January. That process is now expected to conclude prior to Lucas' exit.

Asked about the timing of Lucas' resignation notice, Imation Chief Financial Officer Scott Robinson said, "I just think it was a personal decision for him. He just thought that now was the time to make it public." He added that no other executive changes are expected.

Shares of the Oakdale-based company closed Friday at $4.10 a share, up 5 cents. The stock is at a fraction of its $12 trading price in 2011, as the company has struggled to reinvent itself in the changing world of data storage.

Lucas and other Imation executives have acquired other firms in recent years in an effort to diversify data security product offerings. Results, however, have been slow to change, and the company has frequently operated at a loss.

In letters to shareholders in 2014 and 2015, New York-based activist investors called the Clinton Group accused Lucas and other executives of mismanagement and ­misleading investors.

During Imation's annual meeting in Lake Elmo in May, the Clinton Group won a proxy battle, gaining three seats on Imation's board. Lucas was one of the three directors unseated, though he kept his CEO role.

New board members include Joseph De Perio, Clinton's senior portfolio manager; data storage executive Robert Fernander; and Barry Kasoff, president of Realization Services Inc.

De Perio said in May that the board would meet immediately to figure out the ­company's next moves.

Also ousted from the board were Chairman L. White Matthews and two-year member David B. Stevens.

Officials from the Clinton Group could not be reached for comment Friday.

Staff writer Patrick Kennedy contributed to this report.