The inventor of the copier, Chester Carlson, was originally a patent attorney, part-time researcher and inventor. His job at the New York Patent Office required copying numerous important documents. Carlson suffered from arthritis and found copying files a painful and monotonous task. This encouraged him to experiment with photoconductivity, figuring that it would be easiest to make photocopies. Carlson conducted electrophotography experiments in his home kitchen and applied for a patent for the process technology in 1938. He made the first photocopies using sheets of zinc masked with sulfur. He built the first "photocopying machine" using a zinc plate coated with sulfur. The words "10-22-38 Astoria" were printed on a microscope slide that was placed on sulfur and exposed to a bright light. After the slides were taken away, the mirror image of those words remained on the brimstone. Carlson planned to sell his invention to a number of companies, but the process failed to materialize because of its immaturity. In that era, a large amount of copying work was done using carbon paper or copying machines, and there was no strong demand for electronic copying machines. Between 1939 and 1944, Carlson was rejected by more than 20 companies, including IBM and GE, none of which thought there would be significant market demand for photocopiers. In 1944, the Battelle Memorial Institute, a non-profit organization in Columbus, Ohio, contracted Carlson to perfect his new process. Over the next five years, the agency conducted many experiments to improve the electrophotographic process. In 1947 Haloid (a small New York-based organization that manufactured and sold photographic paper at the time) approached Battelle to obtain a license to develop and sell a copier based on this technology. Haloid realized that the term "electrophotography" was too complex and not very memorable. After consulting with a professor of classical languages ??at Ohio State University, Haloid and Carlson changed the name of the process to "Xerography," derived from the Greek word for "dry writing." Haloid decided to call the new copier "Xerox," and in 1948 Xerox became a trademark. In the early 1950s, RCA (Radio Corporation of America) developed a series of processes called Electrofax, in which images were produced directly on special laminated paper, using liquid toner for coloring. . Application In 1949, Xerox developed the first electrostatic image copier called the Model A. Xerox was so successful that the photocopying technology came to be known as "Xeroxing," and Xerox responded aggressively to prevent "xerox" from becoming a generic trademark. "Xerox" appears in some dictionaries as a synonym for photocopying, which resulted in Xerox sending letters and ads asking them to change those entries and asking people not to use "Xerox" that way. However, this is only the case in North America. For example, "photocopying" was far more commonly used than "Xeroxing" in the British Isles, perhaps because the number of photocopiers from Japanese and European manufacturers far outnumbered those produced by Xerox after photocopying technology became popular. Mixed terms are used in some languages, such as kserokopia ("xerocopy"), which is widely used in Polish, although Xerox's trademarked photocopiers have a small market share. With the advancement of technology, electrostatic copying technology was born. First, a high-contrast electrostatic image is generated on the toner drum, and then a meltable plastic powder (called toner) is transferred to ordinary paper, and is heated and melted onto the paper. This The process is similar to the technology used in laser printers. Technological advances led to the development of the art of color photocopying and xerography in the 1970s and 1980s. Some products marketed as photocopiers use inkjet or film transfer technology to replace the cartridge-based process.