Kalamazoo's former chief executive Malcolm Roberts said he left the company because the job had become "mundane".
Fred Wright, previously sales and operations director, has taken the new position of chief operating officer at Kalamazoo.
Mr Wright has been on the board for more than three years.
Mr Roberts said: “The change process at Kalamazoo is over and the company is far more efficient than ever before. My job was becoming mundane and I was going off the boil.
“My maximum attention span is normally around two years, and I had been there since June 1998.”
Kalamazoo's annual report shows sales grew by 13% to £25.6m in the six months to March 31, but were down by 23% to £48.3m for the year as a whole. Losses were reduced from £6.9m to £4.3m and net assets fell from £9.3m to £5.1m.