Types of Printers Points : write a brief notes on each of the following types of printers. classify the difference between them in terms of speed, quantity of printing, method of operation and suggest suitable application of each of the following, dot matrix printer, daisy wheel printers, drum printers, laser printer, ink-jet printer, advantages of laser printer i. Dot Matrix Printer: They are output devices and are basically impact printers they can be classified as character print because they print one character at a time. They print by striking the ribbon against paper. They have only one head to print a complete line character wise. They can print one character at a time and then to next character position. The head has a pin like hammer which strikes the ribbon and print the character in dotted form. They also use NLQ (Near letter quality) in printing. They can also produce pictures, drawings or graphics. Their speed is from 30 to 600 CPs (characters per seconds). They can produce carbon copies which increases their demand in the market. ii. Daisy Wheel Printers: Daisy wheel are the output devices they belong to impact printers groups and can also be classified as a character printer because they print one character at a time. They have a wheel to print on which characters are embossed. An electric motor spins the wheel and a hammer strikes the ribbon to print characters on paper. They give much better output than dot matrix printers. They are also known as better quality printers. They cannot produce pictures, drawings or graphics. Their speed is from 10 to 90 CPs. They are slower than dot matrix printers. They can produce carbon copies. iii. Drum Printers: The drum printer (or barrel printer) consists of a cylindrical steel drum with embossed characters on its surface. Each column on the drum contains all the possible characters. The number of column is equal to the number of print positions on a line. Most of the drums use 96,120,132 and 160 lines, with 132 characters per line. The most popular for each possible print position that is opposite to each column of the drum, there is a print hammer located behind the paper. The drum rotates at high speed it takes about 60 milli seconds to make one complete revolution and these hammers strike the paper along with the inked ribbon, against the proper character on the drum as it passes one revolution of drum is required to print each line, speeds of drum printers vary from 200 to over 2000 lines per minutes. iv. Later Printer: Laser printer technology is much less mechanical than impact printing (that is no print heads move, no printer hammers hit) resulting in much higher speed and quitter operation. The process resembles the operation of a photocopy machine. A laser beam “writes” an image onto the surface of a light sensitive rotating drum. The ink like toner, deposited on the drum. It adheres where the image was “written”. The toner is then transferred to paper a page at a time in the same function as a photocopy machine. Advantages of Laser Printer:

The major advantages of laser printers are:

• Very high speed.
• Low noise level.
• Low maintenance requirements.
• Very high image quality.
• Excellent graphic capabilities.
• A variety of type size and styles.
A printing speed of laser a printer is between 10,000 and 20,000 lines (about 300 pages) per minute.

v. Ink-Jet Printer: An inkjet printer forms images by spraying tiny droplets of ink from jet nozzles into the paper. The inks which is charged, passes through an electric field, which deflects it to produce a dot-matrix character. Inkjet printers by using multiple nozzle, can print in several different colors of ink color, inkjet printers offers an excellent middle ground between dot matrix and laser printer providing print resolution of around 360 dots per inch. Like laser printers, inkjet printers are quiet convenient, but they are not particularly fast.