Plenum Chairman to Head Irvine’s Gradco Systems : Appointment: Martin E. Tash is installed as chief executive after a successful proxy fight to gain control of the Irvine-based company.

Plenum Publishing Corp. Chairman Martin E. Tash has been installed as chief executive of Gradco Systems Inc. after his successful proxy fight to gain control of the Irvine office equipment company.

Tash’s appointment came Friday at the first meeting of Gradco’s new board of directors. He replaces Gradco founder Keith B. Stewart, who resigned as chairman and chief executive after Plenum gained three of five seats on Gradco’s board in a proxy contest.

Gradco’s new directors also appointed Joseph C. Sanchez as president and chief operating officer of the Irvine office equipment company. He replaces Albert B. Boese as chief operating officer.

Other executive appointments announced Friday were: Harland L. Mischler, chief financial officer; Bernard Bressler, corporate secretary; James Owens, treasurer, and David J. Harshman, assistant secretary and general counsel.

Plenum officials have said that they will also seek to oust Stewart as chairman of Gradco’s Japanese subsidiary, which makes sorters for office copiers.

Stewart, who is Gradco’s largest shareholder, has vowed to remain in control of the Japanese subsidiary. The former chairman has also hinted that he may seek to regain control of Gradco.

Gradco, the world’s leading independent supplier of sorters, sheet feeders and other paper-handling devices for office copiers, lost $28.1 million for the year ended March 31.

Much of the loss came after it lost a contract with Xerox Corp., its largest customer.

The dissident group headed by Tash also criticized Stewart and other board members for issuing themselves 2.5 million in warrants to acquire a 17% interest in Gradco Japan.