There are numerous different methods of printing. These methods are divided into two categories: impact and non-impact printing.
Most of us are familiar with impact printing; most common is the typewriter, Dot Matrix Printers. Non-impact printing is a method of transferring material onto a media without contact. These methods include, photocopying, laser printing, thermal transfer, bubble and ink jet printing.

Printer is a device that prints text or graphics on paper. There are various kinds of printers. Printers are categorized depending on the distinct technologies employed as:

Alike the ball-head typewriter, this type of printer has a plastic or metal wheel on which the shape of each character stands out in relief. A hammer presses the wheel against a ribbon, which in turn makes an ink stain in the shape of the character on the paper. Text result can be produced by a Daisy-wheel but not graphics.

Generates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations.

Ink-jet printers yield high-quality text and graphics. Print is generated by spraying ink drops of different sizes at a sheet of paper resulting in text or graphics.

A Laser Printer is the commonly used printer in today’s times due to its time and cost efficiency and superior yield Very high quality text and graphics is produced by laser printers.

Liquid Crystal Display (LCD) Printers use single light source for generating a print result; whereas Light-emitting Diodes (LED) printer are used to yield image.

As the name suggests Line Printer prints a complete line of characters at a time. Earlier, Line Printers were the fastest printers generating quantitative results; however are replaced by Laser printers in modern times which give qualitative result also.

It is an inexpensive printer that works by heating a certain part of the heat-sensitive paper by special pins against paper.

Daisy wheel printer is one among the Impact Printers. It is very similar to typewriter. It works on a similar principle as of ball-head typewriter. The wheel in a daisy wheel printer is a disk made of plastic or metal with many spokes like the petals of a daisy. There are characters or letters on the outer rim of each spoke in relief. To print a character, the daisy wheel rotates until the desired letter faces the paper. Then a hammer hits the particular spoke on the wheel, imposing the character onto the ink ribbon, leaving an imprint of the character on the paper below. Daisy wheel printer proves to be advantageous for producing letter-quality text.
Daisy-wheel printer cannot print graphics or more than one font in the same document. The daisy wheel needs to be changed to provide different fonts. Daisy-wheel printer is normally very slow and loud while it functions. With the advancement in the technology it is becoming outdated and is being replaced by Inkjet or Laser Printers.

Dot-matrix printer is an Impact Printer. It uses a set of closely spaced pins and a ribbon to print letters or other characters on the page. These printers make an impact on the page to print a character, much like a typewriter. In a dot-matrix printer rows of pins strike the ribbon in patterns, leaving closely grouped dots shaping into numbers, characters and even images. Dot-matrix printers vary in terms of speed and the number of pins they have. They are speedy alternatives to Typewriters or Daisy Wheel Printers. The number of pins, which can vary from 9 to 24, determines the quality of the print job.
While speedy, these printers suffer from relatively poor print quality. Even higher-end models with as many as 48 pins can produce only near-letter-quality text. Lower-end, 9-pin models are suitable only for printing drafts. Though Dot-matrix printers are relatively expensive and do not produce high-quality output, they can print several copies, something laser and ink-jet printers cannot do. However, compared to laser and ink-jet printers, dot-matrix printers are well-known for making an ear-splitting whining noise.

A Line Printer is an Impact Printer which prints one line at a time. There exist two technologies in Line Printers- Band printers and Line matrix printers.
It is a speedy printer. A fast line printer can print as many as 3,000 lpm, however it cannot print graphics, the print quality is low, and they are very noisy.

An Inkjet Printer is one of the Non-Impact Printers. A simple to use, inexpensive printer-inkjet has developed into high quality short-run printers. Through an Inkjet Printer characters are formed as a result of electrically charged or heated ink being sprayed through fine jets onto the paper. The ink cartridge in an inkjet cartridge contains all the imaging components needed to get an image from the computer onto a sheet of paper. These components are compartments of ink sealed with a metal plate, thin tubes from the ink source to each well, and the jet at the bottom of each compartment (a tiny pinhole that sends ink onto the page). When the printer receives the command from the computer’s operating system to print an image, the printer starts the printing process: An electrical current warms the heating element, which is submerged in the ink source. As the element heats, the ink vaporize, creating pressure in the compartments. This pressure in the cartridge is controlled by the degree of heat and is responsible for forcing the expanding ink out of the microscopic pinhole. Only one drop at a time can escape from the ink cartridge—but it happens fast enough to create entire images in less than a minute.
A black cartridge generates monochrome output, where as color cartridges combine magenta, yellow and cyan inks to create color tones. The ink cartridge should be replaced when it runs out of ink.
An alternative ink-jet technology is the bubble-jet printer, which use miniature heating elements. It forces the specially formulated inks through print heads with tiny nozzles. The multiple nozzles print fine images at high speeds. This technology is commonly used in portable printers.

A Laser Printer is a Non-Impact Printer which creates images by shining a laser beam onto a photoconductive drum to produce an image. The high intensity laser beam discharges selected areas on the charged drum. These discharged areas correspond to the white areas of the printed document. The drum then rolls through toner, and the electrically charged portions of the drum pick up ink. Finally, using a combination of heat and pressure, the ink on the drum is transferred onto the page.
Laser printers are quiet and print very fast, and the supply cartridges work a long time. They produce sharp, crisp images of both text and graphics. They can print in many fonts (type styles and sizes). The more expensive models can print in different colors.

LED-LCD printers are the Nom-Impact Printers. These are electro photographic printers largely identical to laser printers. The difference between the two technologies lies in the method of light distribution.
Both LCD (liquid crystal display) and LED (light-emitting diode) printers use a light source instead of a laser to create an image on a drum. The process of printing is similar to the laser printing process. However the LED printers use Light Emitting Diodes to charge the drum, and the LCD uses Liquid Crystals.
These printers produce a very high quality text and graphics print out.

A thermal printer is a Non –Impact printer which uses heat to transfer an impression onto paper. It produces image by placing heated elements in contact with special heat sensitive paper. This paper is called as coated thermochromic paper, or thermal paper. The paper passes over the thermal print head forming darkened dots when the elements reach a significant temperature, producing an image. There are two kinds of thermal printers:

This printer adheres wax-based ink onto paper.

This printer prints the image by burning dots onto coated paper when the paper passes over a line of heating elements.