The next time you need typewriter ribbons . . . or other office supplies," read the letter sent to all members of the House of Representatives, "please keep Stovall Evans and Co. in mind."

The sales pitch didn't come from an aggressive marketing manager, but from D.C., Del. Walter E. Fauntroy, on his official congressional stationery.

A spokesman for Fauntroy said the District's nonvoting delegate touted the firm because it is minority-owned and that such support "is in line with the administration's policy of aiding minority businesses."

The three-paragraph letter was dated Oct. 31 but it wasn't distributed until this week.

The letter begins by saying that "you may have noticed a new line of products in the Office Supply Service Store at the Longworth Building, Room B217. The products are manufactured by the Lift-Off Corp. of Hickory, N.C. The sole marketing representative in the Washington metropolitan area is Stovall Evans and Co . . . (The firm), incorporated in the District of Columbia, is a minority owned and controlled corporation engaged primarily in the marketing of office supplies."

Fauntroy goes on to list the "extensive marketing backgrounds" of William H. Stovall Jr., director of marketing activities, and Carl G. Evans, president. Fauntroy added that the firm has "a philosophy which demands that (it) market only quality and tested products, back-up its marketing with service, and market their products at sensible prices."

Fauntroy was out of town yesterday and could not be reached for comment. But an aide said Stovall and Evans approached Fauntroy for his support, after they already had gotten their goods into the House office supply store. The spokesman said Fauntroy had no financial interest in the firm and no business dealings with its owners.

"Dear Colleague' letters are a growing fad among congressmen. The Fauntroy aide said the District delegate had "received about 100 from other members," although he could find none that suggested the purchase of a product.

The practice of writing "Dear Colleague" appeals was criticized by Rep. Otis Pike (D-N.Y.) in the current edition of Roll Call, a Capitol Hill weekly newspaper. Pike said he received 217 of them in a recent two-week period, bearing messages such as "Dear Colleagues, are you against sin? . . . are you for America and apple pie? . . . would you like to be re-elected?"

One person who was jubilant about the Fauntroy letter was Richard Plyler, board chairman of the Lift-Off Corp. Plyler said his small firm was begun in April, 1975, and since Stovall Evans became his Washington distributors "we have at least 10 times the business up there."