How to Work a Photocopier Machine

Photocopier

How to Work a Photocopier Machine
Is a machine with which one can have an exact photocopy of an original print, Chester Carlson a law student invented the process called xerography in 1938, Xerography comes from the Greek word "Xerox" meaning "dry writing", in 1950. Xerox Corporation made xerography or photocopying commercially available, Hence. Photocopiers are commonly known as Xerox machine.

Principle

Working of a photocopier is based on the principle of photoconductivity and Coulomb's law; photoconductivity is the property by virtue of which certain substance like carbon sulphide and selenium conduct. When light is incident on them, Coulomb's law states that, like chargers repel while unlike chargers attract.
When choosing the photocopier for your office, make sure you look at the features that are must have for your work environment.



How to work a Photocopier?

Photocopying involves several technical processes. Light is reflected from the original document so that an image of the document is projected onto an electrically charged photoconductive drum. The photo conductor is generally the element selenium. The reflection of the document leaves a pattern of charges on the drum surface that is identical to the original document. These charges attract the toner, which is then transferred to the copy paper.
The process involves heat or pressure in conjunction with an electrical discharge from the drum.
  1. Charging: cylindrical drum is electrostatically charged by a high voltage wire called a corona wire or a charge roller. The drum has a coating of a photoconductive material. A photoconductor is a semiconductor that becomes conductive when exposed to light.
  2. Exposure: A bright lamp illuminates the original document and the white areas of the original document reflect the light onto the surface of the photoconductive drum. The areas of the drum that are exposed to light become conductive and therefore discharge to the ground. The area of the drum not exposed to light (those areas that correspond to black portions of the original document) remains negatively charged.
  3. Developing: The toner is positively charged. When it is applied to the drum to develop the image, it is attracted and sticks to the areas that are negatively charged (black areas), just as paper sticks to a balloon with a static charge.
  4. Transfer: The resulting toner image on the surface of the drum is transferred from the drum onto a piece of paper with a higher negative charge than the drum.
  5. Fusing: The toner is melted and bonded to the paper by heat and pressure rollers.

A negative photocopy inverts the color of the document when creating a photocopy, resulting in letters that appear white on a black background instead of black on a white background. Negative photocopies of old or faded documents sometimes produce documents which have better focus and are easier to read and study.

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