Exxon Corp. confirmed yesterday that it is seeking a buyer for its troubled electronic office equipment business.

In confirming the company's plans to sell the business, however, an Exxon spokesman disputed reports that the oil giant has spent more than $1 billion over the past decade without gaining any significant share of the market.

The Exxon spokesman said the division's total physical assets in receivables are worth only about $100 million. It is not known how much more the company has invested in research and development work that would have to be scrapped and written off.

A company source said Exxon has so far been unable to find a buyer for the division, despite discussions with companies in Japan and the United States, and may have to shut the operation down.

Should that happen, sources and analysts say, Exxon would likely have to write off several hundred million dollars worth of investment in the venture.

Exxon's stock, traded on the New York Stock Exchange, fell 5/8 yesterday to 42 7/8

Exxon's confirmation that it is trying to drop the office systems division ends several years of speculation about what the company would do with the business. Begun in the mid-1970s, the move into such products as word processors and electronic typewriters was seen as a major diversification move by the world's largest company away from the oil and gas business. Exxon had hoped to build the office systems division into $1 billion in sales by 1985, and compete with such industry giants as International Business Machines Corp. and Xerox Corp.

Despite some early successes with Vydec word processors, Qyx typewriters and Qwip facsimile transmitters, the unit never lived up to Exxon's expectations. The company was unable to come up with new, innovative and practical products in the fast-moving electronic office equipment field, and Exxon's share of the overall market was negligible. Annual sales of the division never rose much above the $200 million level, and it continually lost money. A company source said the division will lose more than $70 million this year, more than one-third of its revenue.

Analysts say Exxon apparently did not fully appreciate the subtleties of the high-tech electronic fields it had entered and was unable to move quickly enough to cope with changing markets.