In the land of the rising profit, Japanese executives are busily trying to make the names of Ricob, Sharp and Minolta as familiar as Toyota, Datsun and Honda.

In addition to cars, cameras and computers, the Japanese are successfully competing in the paper-copier business. The Japanese copier executive's dream is to have an office worker ask "Make a Ricoh copy for me," instead of a Xerox copy or "Can you Minolta this?" instead of Xerox it.

Which leaves some American executives wondering if copiers will go the way of cars.

"When anybody cuts into a traditional market, they should be concerned," said Dale Kredatus, a senior consultant for Datapro Research Inc. "But the concern should have been made a few years ago."

Just as American automakers for years were interested almost exclusively in large, high-profit automobiles, the nation's paper copying companies concentrated on large, high-volume, high-profit copiers. Detroit executives left a void in the small-car market that the Japanese were eager to fill. Similarly, a void was left in the small, desk-type paper copier industry that the Japanese swiftly gobbled up, industry analysts said.

The major concern of American copier companies is that the Japanese will get a foothold in the $6 billion business and eventually squeeze into the multibillion-dollar high-technology office of the future. What will the Americans do about it? "Cry a lot," said Eugene G. Glazer, a vice president at Dean Witter Reynolds Inc.

"A marketplace has been ignored by them and developed by us," said Joseph Castrianni, a vice president for Sharp Electronics Corp., a subsidiary of Japan's Sharp Corp.

Is Xerox worried? "I prefer the word concern," said Xerox Vice President John Schlachtenhaufen. "Obviously we intend to be the leading force in the office of the future."

Xerox, the indisputed leader in the paper-copier business, has decided it has ignored for too long the moms and pops of the business world who are buying small, low-volume paper copiers. To combat the Japanese threat in the small copier market, Xerox has "totally restructured our organization to focus on the small-business marketplace," Schlachtenhaufen said. "That's where most of this explosive growth is coming from."

Schlachtenhaufen said there are about 10 million small-business and home-copier users that Xerox is targeting. The firm will open retail stores around the country with small copiers and other business equipment for the small office. Xerox is also "testing alternative ways to get to these 10 million" potential small-business buyers and is marketing its own small copier models, Schlachtenhaufen said.

"We have expressed a high degree of concern for some time about the acceleration in the competition from the Japanese," said a report from Dean Witter. "Recent events tend to substantiate a cautious view relative to developments in the copier market."

The Japanese influx started in about 1975, Glazer said. "The Japanese finally designed a good product that was reliable and cheap enough in cost so they could find a place in the market," Glazer said. "Before, it was almost all Xerox."

Because it was too expensive and time-consuming to develop their own dealer network like Xerox did, the Japanese companies sold through other office equipment dealers. And because their machines were smaller and cheaper, they could sell them rather than lease them and make them available to smaller offices.

Last year the total plain paper copier sales and leasing market (excluding the shiny, lower quality electrofax copying) was $6 billion, up from $2.4 billion in 1975, according to Dataquest Inc., a California research firm.

Of all the copiers sold or leased last year, 315,000 were American made and 219,000 were made by Japanese firms. That's an increase from 36,000 machines placed by American firms in 1975 and 11,000 placed by Japanese companies.

In 1972, 6 percent of the copiers worldwide were made in Japan. Last year 79 percent were made by Japanese companies. In the revenue area, however, Americans still lead. Last year U.S. copier revenues were $4.4 billion compared with $1.7 billion for the Japanese. In 1975 U.S. firms had $2.2 billion in business compared with $208 million by the Japanese.

The leading paper-copier firms in terms of sales are Xerox; Ibm; Savin Corp., which distributes Japan's Ricoh copiers; Eastman Kodak Co. and Canon, another Japanese firm.

"In Japan, the national priority is penetration of high-technology markets," Dean Witter's Glazer said. "Some suggest the Japanese will fail. The Japanese are good at designing a very reliable product with simple design. They're not necessarily good at designing a total integrated system" for complex office communications and processing networks of the future.

"The products we make are very simple in design," Sharp's Castrianni said. But Castrainni said that Xerox's "concern is probably a good one. Five years from now, maybe," the Japanese firms will have penetrated the more complicated and expensive copier systems . . . We will develop products for the office of the future."