PRINTERS AND ITS TYPES

PRINTERS AND ITS TYPES

PRINTERS

Printer - A device that prints text or illustrations on paper. There are many different types of printers. In terms of the technology utilized, printers fall into the following categories:

Impact Printers : In this hammers or pins strike against a ribbon and paper to print the text. This mechanism is known as electro-mechanical mechanism. They are of two types.

Character Printer : It prints only one character at a time. It has relatively slower speed. Eg. Of them are Dot matrix printers.

 

Dot Matrix Printer : It prints characters as combination of dots. Dot matrix printers are the most popular among serial printers. These have a matrix of pins on the print head of the printer which form the character. The computer memory sends one character at a time to be printed by the printer. There is a carbon between the pins & the paper. The words get printed on the paper when the pin strikes the carbon. There are generally 24 pins.

Laser Printer: A type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work.

 

The 6 steps laser printing process



1. Cleaning – The Photosensitive drum is cleaned before it can take on a new image
2. Conditioning or Charging – To make the drum receptive to new images, it must be charged. The EP drum is given a negative charge by the primary corona wire around -600 and -1000 volts
3. Writing - A laser beam is use to write to the EP drum causing dots on the drum to lose some of the negative charge
and become relatively positive charge
4. Developing - A toner is transferred from the toner cylinder to the EP drum by attracting the area of the drum that has a
Relative positive charge
5. Transferring - The transfer corona wire puts a highly positive charge on the paper once the paper has a positive charge
the negatively charge toner particle leaps from the drum into the paper
6. Fusing - The compression roller and fusing roller press and melts the toner into the paper the fuser gets very hot

Other Types of Printers

Photo Printer – Is a type of printer use for printing photographs.

Dye-Sublimation Printer – Is a type of printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, printer paper or poster paper.

Thermal Printer- Is a type of printer that produces a printed image by selectively heating coated thermo chromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated which then produce an image.

All-in-One Printer - A printer than can also do scanning, fax and make copies

Plotter - A large device use to print large posters and documents

Non-Impact Printers : There printers use non-Impact technology such as ink-jet or laser technology. There printers provide better quality of O/P at higher speed. 

These printers are of two types :

 

Ink-Jet Printer : It prints characters by spraying patterns of ink on the paper from a nozzle or jet. It prints from nozzles having very fine holes, from which a specially made ink is pumped out to create various letters and shapes. The ink comes out of the nozzle in a form of vapors. After passing through a reflecting plate, it forms the desired letter/shape at the desired place.