In the 1930s, Chester F. Carlson was working in the patents department of a large electronics firm in New York City. One of the major problems in his work was the length of time and expense involved in getting patents copied, patents were lengthy legal documents, and the only ways to get them copied were to take them to a typist or to take them to a photographer. Either way of copying patents took a lot of time and cost a lot of money. He came up with the idea for a machine that would copy documents quickly and efficiently. He researched the idea in the library and then worked over a three-year period on developing a machine that used a light, an electro statically charged plate, and powder to duplicate images on paper. The result of this work was a machine that produced the first xerographic copy on October 22, 1938. He named the process "Xerox", which means "dry writing". Carlson felt that he had a good idea, one that would be extremely helpful in the business world. He tried to sell his idea to a number of large corporations, but they were not terribly interested in his machine. A few years later he sold the process to a small family-owned company. This small company grew into the giant Xerox Corporation, and both Carlson and Xerox became rather wealthy in the process.

The following are the components Carlson used for his newly-invented machine, EXCEPT ....