His son Eric R. Gundlach confirmed his death. The cause was aspiration pneumonia.

Mr. Gundlach was a 26-year-old physicist in 1952 when he joined the Haloid Company, the business that would become Xerox. There, he worked with Chester Carlson, known as the inventor of xerography, the basic technology behind photocopying.

In his first year on the job, Mr. Gundlach produced three inventions that garnered patents, including an innovation in offset duplicating that had evaded a team of other scientists for several years. By 1959, in part because of Mr. Gundlach’s research, Haloid Xerox unleashed what it billed as the world’s first automatic plain-paper copier.

By the time he retired from the company in 1995, Mr. Gundlach had 155 patents to his name on behalf of Xerox. His final contribution was an inkjet process that produced glossy images akin to a photograph on plain paper.

Mr. Gundlach’s inventions earned him a trove of professional distinctions, particularly induction into the National Inventors Hall of Fame in 2005. In 1966, Xerox selected him as its first research fellow, the highest nonmanagerial post occupied by a company scientist. In 1994, Mr. Gundlach was elected to the National Academy of Engineering.

Born in Buffalo on Sept. 7, 1926, Robert W. Gundlach was the youngest of three boys. He completed his undergraduate studies at the University of Buffalo in 1949, then pursued graduate studies there.

Besides his son Eric, Mr. Gundlach is survived by his wife of 60 years, Audrey B. Gundlach; his brother, Arthur Gundlach; two sons, Gregory E. Gundlach and Kurt B. Gundlach; and 10 grandchildren.

Though inventing filled his working hours, Mr. Gundlach was enthralled with canoeing, hiking, skiing — activities he pursued avidly most of his lifetime. When he was in his 50s, feeling the need for a new hobby, he took up windsurfing. He also made sure to be home from work in time to play ball or build a bicycle jump, his children recalled.

“He had what we would call today a work-life balance,” said Eric Gundlach. “He was the kind of man who left work behind.”