The Reagan Administration's continuing effort to trim the federal budget has struck a raw nerve with American inventors. To pay for its overhead costs, the United States Patent and Trademark Office has proposed raising an applicant's patent fees from an average of $230 to as high as $3,200.

According to estimates, up to three-quarters of all technical innovations are generated by independent inventors working outside corporate research labs. Many of them lack the resources to absorb the substantial increases proposed by the government. "If our purpose is to destroy creativity in this country, we're on the right track," says Melvin L. Fuller, president of Inventors Workshop International of Ventura, Calif., a group with more than 7,000 members.

The current filing and issuance fee of $230 is already scheduled to rise to $800 this October. The patent office says the higher fees would enable it to recoup 58% of its cost of operation.

More recently, in response to the Reagan Administration's budget cutbacks, Gerald J. Mossinghoff, commissioner of patents and trademarks, has proposed a new set of charges aimed at recovering virtually all of his office's overhead. To achieve this goal, experts figure the fees -- including those for filing, issuance, and, for the first time, maintenance -- would rise to about $3,200 over the life of a patent. About $300 would be required when the patent was filed, $500 when it was issued, and the remainder in three installments during its 17-year lifetime.

Critics worry that if the proposed charges are instituted, small inventors will be discouraged from registering their ideas. As a consequence, they say, innovation will be stifled and the American economy will pay the price down the road with lower productivity. "To try to squeeze inventors to pay for pencils and paper just doesen't make sense," says Joseph Iandiorio, a Waltham, Mass., patent attorney. "It's a real killer for small businesspeople."