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Fact File

Saturday, December 4, 1999

Chester F. Carlson
By Illa Vij

XEROGRAPHY (the word is derived from two Greek words meaning dry and writing) was invented by Chester Carlson. Carlson, born in 1906 (exact date is not available), belonged to a family that had to struggle for its livelihood. At the age of 12, a lean and thin boy, he did odd jobs in California, adding to the resources of the family.

By the age of 14, Carlson became the main supporting member of the family as both his parents were invalids. He was up at 5 a.m. and worked all day. Under such circumstances most boys would probably drop out of school, but Carlson was determined to carry on. On Saturdays and Sundays, he worked in a chemical laboratory. When he was 17 years old, his mother passed away. He wanted to gain a degree in physics. With an ailing father to support and financial constraints, it was tough on him. He managed to get a degree in physics, but by then he had a debt of Rs 6,600.

Despite the degree in hand, he couldn’t manage a job. He applied to over 80 firms, but in vain. He finally joined a New York electronics firm. While working there he realised the dire need of a machine that could copy the original. He thought of the great advantage and convenience that such a machine could provide.

In 1935, he started working on his idea. For three years he worked all alone, spent hours and hours reading and trying to work out a solution to his problem. He was carrying out three tasks at a time. He was studying for a law degree and had to attend evening classes. He held a job for survival and also pursued his dream. He worked in a tiny room in a suburb of Astoria.

His investigations finally brought him successful results. On October 22, 1938, he wrote the words "10-22-38 Astoria", and he used his invention to bring out an exact copy of the same. It was the first electrostatic copying. This was later called xerography, which means ‘dry writing’. With the invention by his side, he knocked the doors of numerous companies, but nobody seemed to be interested in his work.

The Battele Memorial Institute, a non-profit organisation did agree to support him, but financially, it wasn’t working out well for Chester. He got a real break when the Haloid Company, later called Xerox Corporation, negotiated with him for commercial rights. In 1950, the first Xerox machines were available in the American market. The Xerox company saw the bright future of this great invention and they put in millions of dollars into further research work and marketing. Then the Rank Xerox Ltd. owned by the Rank organisation (J. Arthur Rank had a chain of cinemas under him), and Xerox Corporation was launched in Britain to market the machines to various countries. Within a couple of years, the profits of the Rank Xerox multiplied over a hundred times. The wonder that the machine does for us, is beyond expression. Almost every student, teacher, office employee — practically everybody — uses it. Carlson, finally got to live in great comfort and enjoyed the fruits of his hard labour.

Photocopying

Photocopying is any of several methods of making copies of documents or illustrations. All these processes use light-sensitive materials. The documents may be typed, printed, or handwritten. Illustrations include photographs, drawings, or prints. The chief photocopying methods are (1) projection photocopying, (2) contact photocopying, and (3) electrostatic photocopying.

Projection photocopying was developed in the early 1800s. Common projection copiers include the copy camera and the photostat machine. A copy camera takes a photograph of the original. The film is then developed, producing a negative. To make a positive copy the image on the negative is projected onto positive paper. Finally, the paper is developed to create the copy. Copy cameras can enlarge or reduce the size of the copy made from the original. This feature makes them valuable in commercial art and many other fields.

A photostat machine does not use photographic film to make a negative. It forms a negative of the original directly on light-sensitive paper. The paper is then developed, producing the copy. Photostat machines have many uses. One type is used to enlarge and copy images from microfilm.

Contact photocopying was first used in the mid 1800s. In this method, the original is placed in contact with light-sensitive negative paper and exposed to light. Next, the negative paper is held against positive paper and the two papers are fed into a contact-copying machine. There, they pass through a developer such as ammonia vapour or water. The developer brings out the image on the negative and transfers it to the positive paper. The positive paper becomes the copy. Blue print and similar types of duplicates are made by contact photocopying.

Electrostatic photocopying was invented in 1938 by Chester F. Carlson, an American physicist. Unlike the earlier methods, which require liquid developers Carlson’s process is completely dry. It became known as xerography, a term that comes from two Greek words xeros, meaning dry, and graphia, meaning writing.

In xerography, a drum, belt, or plate coated with the element selenium or some other light-sensitive material is charged with static electricity. Light is reflected from the original through a lens. A positively charged image corresponding to the dark areas of the original then forms on the light-sensitive surface. The rest of the surface loses its charge of static electricity. Negatively charged toner (powdered ink) is dusted onto the surface and sticks to the image. The inked image is then transferred to a positively charged paper and heated for an instant. The heat melts the toner and creates a permanent copy. In other electrostatic methods, the image from the original is projected directly onto specially coated paper, rather than onto a drum, belt, or plate.

Electrostatic copiers, which revolutionised office work and the copying industry, can perform a wide variety of jobs. Some can make as many as two copies a second — and sort and staple copies of different originals as they come from the machine.Others can print on both sides of the paper, reduce and enlarge the image copied and duplicate colour originals.