- Also called:
- photocopier, copy machine, photocopy machine, copier machine, or photocopying machine
- Related Topics:
- electrophotography
copier
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What is a copier?
A copier is a device that creates duplicates of text or graphic materials using light, heat, chemicals, or electrostatic charges.
Xerography, the method used by modern office copiers, applies electrostatic charges and heat. This process uses a selenium-coated aluminum drum. Light reflects from the original document onto the drum's surface, attracting negatively charged ink particles (toner). The image transfers to copy paper with a positive electric charge. Heat fuses the ink to the paper.
Another method uses the heat of infrared light. In this process, sensitized copy paper is placed in contact with the original, and both are exposed to infrared rays, transferring the impressions to the surface of the copy paper.
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How does a copier work to make copies of documents?
A copier makes copies using xerography, a process involving electrostatic charges and heat. This method relies on photoconductivity, where substances increase their ability to conduct electric current when exposed to light.
Here's how it works: An aluminum drum coated with selenium is exposed to light from the document, creating an image on the drum's surface. Negatively charged ink particles (toner) are sprayed onto the drum, forming the image. Then, a positively charged sheet of paper attracts the toner, transferring the image. Finally, heat fuses the ink to the paper.
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What are the main parts of a copier?
A modern office copier employs a method called xerography, which utilizes electrostatic charges and heat to produce copies of text or graphic material.
At the core of xerography is a photoconductive substance, such as selenium, coated on an aluminum drum. When light reflects off the original document and strikes the drum, negatively charged ink particles (toner) are sprayed onto the drum, forming an image. A sheet of paper then passes by the drum, and a positive charge attracts the toner, transferring the image onto the paper. Finally, heat fuses the ink to the paper, creating the copy.
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How is a copier different from a printer or scanner?
A copier duplicates text or graphics using light, heat, chemicals, or electrostatic charges. Modern copiers use xerography, applying electrostatic charges and heat to produce copies of various materials.
A printer transfers text files or images from a computer to paper or film, using methods such as laser, ink-jet, or thermal processes.
A scanner uses a light beam to input codes, text, or images into a computer system. Scanners are used in various applications, including retail point-of-sale terminals, fax machines, and personal computers.
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What are some common uses of copiers in schools or offices?
Copiers are essential in schools and offices for reproducing documents quickly and efficiently. The most common type of copier uses xerography, a process involving electrostatic charges and heat to transfer images onto paper. Modern copiers can print on both sides, sort, collate, enlarge, or reduce images, and produce predetermined copies automatically.
In offices and schools, copiers are used to reproduce reports, memos, forms, and other documents. They facilitate the distribution of information, support administrative tasks, and enable the creation of learning materials. The development of copiers has greatly benefited business and government by improving efficiency.
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How have copiers changed over time with new technology?
Copiers have changed significantly with new technology. The most widely used method in modern office copiers is xerography, which applies electrostatic charges and heat to produce copies of all kinds of written, printed, and graphic matter.
Other improvements include printing on both sides, sorting and collating, producing a set number of copies, and enlarging or reducing the image from the original. In the 1990s, the multifunction printer combined the functions of the copier, printer, fax machine, and scanner.
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copier, a device for producing copies of text or graphic material by the use of light, heat, chemicals, or electrostatic charges.
The method most widely used by modern office copiers is called xerography (from the Greek words meaning “dry writing”). Although developed by the U.S. physicist Chester F. Carlson in 1937, the process did not become available for commercial use until 1950. Xerography, which involves the application of electrostatic charges and heat, is extremely versatile and can be employed to produce copies of all kinds of written, printed, and graphic matter. The basis of the process is photoconductivity, an increase in the ability of certain substances to allow an electric current to flow through them when struck by light. The chemical element selenium, for example, is a poor electrical conductor, but when light is absorbed by some of its electrons and a voltage is applied, these electrons are able to pass more freely from one atom to another. When the light is removed, their mobility falls. Xerography typically uses an aluminum drum coated with a layer of selenium. Light passed through the document to be copied, or reflected from its surface, reaches the selenium surface, onto which negatively charged particles of ink (i.e., the toner) are sprayed, forming an image of the document on the drum. A sheet of copy paper is passed close to the drum, and a positive electric charge under the sheet attracts the negatively charged ink particles, resulting in the transfer of the image to the copy paper. Heat is then momentarily applied to fuse the ink particles to the paper. The copy paper itself originally provided the treated surface, but the substitution of the selenium-coated drum permitted the use of ordinary paper. Other improvements were introduced, making it possible to print on both sides of the paper, sort and collate, automatically produce a predetermined number of copies, and enlarge or reduce the image reproduced from the original. Xerographic machines capable of duplicating coloured materials became available in the 1970s, and in the 1990s the multifunction printer combined the functions of the copier, printer, fax machine, and scanner.
Another copying method that became available in the early 1950s uses the heat of infrared light. In this process, sometimes called thermography, sensitized copy paper is placed in contact with the original and both are exposed to infrared rays. The original absorbs the rays in areas darkened by print or by the lines and shades of an illustration and thereby transfers the impressions to the surface of the copy paper. In the early 21st century this process was chiefly used by tattoo artists to create stencils.
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The development of fast and efficient copiers has benefited business and government tremendously. It created copyright problems, however, and stimulated changes to existing copyright laws and regulations in the United States and elsewhere.