All About Printers
A most convenient and useful method by which the computer can deliver information is by means of printed characters. Types of Printers :
Impact Printers
Non-Impact Printers
Impact Printers
In these printers, there is mechanical contact between the print head and paper.
Line Printers
Line Printers
A line printers prints a complete line at time Printing speed vary from 150 lines to 2500 lines per minute with 90 to 100 characters on 15 inch line. Type of line Printers :
Consist of a cylindrical drum on which character are imposed.
Consist of a steel band on which the characters are embossed.
Character Printers
Characters printer print one character at a time with the print head moving across a line, serial printers normally print 30 to 300 character per seconds.Types of character Printers:
Letter Quality printers print full characters. The most popular printer of such a type is classy wheel printer. It is a front type character. In a daisy wheel printers, it print head resembles a daisy flower with its print arms appearing like petals of flowers.
Non-Impact Printers
The natural limitation of speed in electro mechanical devices and cost considerations have let to the development of printers called non-impact printers.
By using magnetic recording techniques, a magnetic image of what is to be printed can be written on a drum surface. Them this surface is passed through magnetic powder which address to charged areas. The powder is pressed on to the paper speeds of upto 250 characters per second are obtained in such system.
Thermal Printers
An electric pulse can be converted to heat on selected section of a printing head or on wires or nibs. When this heat is applied to heat sensitive paper, a character is printed.
Electro static Printers
For electrostatic printers the paper is coated with non conducting dielectric material which holds charges when voltages are applied with nibs. These head write dots, on the paper as it passes. Then the paper passes through a toner which contains material with coloured particles carrying an opposite charge to that written by nibs.
Inkjet Printer
Some printers direct a high-velocity stream of ink toward paper. This stream is deflected, generally by passing if through an electrostatic field such as that used to deflect beam in oscilloscopes. In some system the ink stream is broken into droplets by an ultrasonic transducer.
Laser Printers
These printer make use of office copier technology the desired output image is written on a copier drum with the help of a light beam controlled by a computer. With this certain parts of the drum surface get electrically charged, them this drum surface is exposed to the laser beam. These laser exposed areas attract a toner that form the image by attaching itself to the laser generated charged on the drum. The toner is them permanently fused on paper with hot or pressure.