Mr. Starkweather was working as a junior engineer in the offices of the Xerox Corporation in Rochester, N.Y., in 1964 — several years after the company had introduced the photocopier to American office buildings — when he began working on a version that could transmit information between two distant copiers, so that a person could scan a document in one place and send a copy to someone else in another. He decided that this could best be done with the precision of a laser, another recent invention, which can use amplified light to transfer images onto paper. But then he...