The changes keep coming at Imation Corp.

The beleaguered data storage and security firm tapped one new outside board member to become interim president and another new board member to become chairman, the company announced Wednesday after the market closed.

Wall Street welcomed the news. Shares in Imation’s stock initially rose a nickel a share in early trading Thursday. However, it closed at $3.21 a share, up just a penny.

Oakdale-based Imation, which has been buried in losses for years, said new director Barry Kasoff — a turnaround specialist and the president of Realization Services — will become interim president immediately. New director Joseph De Perio will become chairman.

The changes follow the announced departures of former president and CEO Mark Lucas, interim chairman William LaPerch, and former independent director Tony Brausen.

Lucas, former chairman L. White Matthews and two-year board member David B. Stevens were ousted from the board by shareholders in May after De Perio’s Clinton Group staged a proxy battle. As an activist investor, the Clinton Group demanded three board seats and big changes at the former 3M spinoff that has been hurt by the demise of CDs, magnetic tapes and other recordable media.

Lucas, who steps down as CEO next month, will remain with Imation in a consulting role until the end of the year, officials said.

Imation’s full six-member board is working with an executive search firm to find a permanent CEO.

Imation is wrestling to boost revenue while containing costs that have risen significantly as the company has pursued acquisitions that can transform the company into a data security powerhouse.

In a statement, De Perio thanked the departing board members.

“Together with Barry as interim president, we look forward to continuing to take the necessary steps to position the company for long-term profitable growth,” he said.