Page 67 - Computer - 9(A&B)

Drum Printers: These printers are a special type of line printers. They consist of solid drums
with the raised characters in form of bands. Number of bands are equal to the number of
printing positions and for each band, there is a hammer. The drum rotates at a very high
speed. The hammer strikes the paper through an inked ribbon when the desired character on
the drum passes. The printing speed of these printers can be from 200 to 2000 lpm (lines per
minute).

Non-impact Printers

In non-impact printers, no physical contact between the print head and the paper exists.
Due to this reason, they are almost noiseless printers and their print quality is very high.
These are very fast printers as they can print many pages in one minute. Their speed is
usually measured in ppm (pages per minute).
The commonly used non-impact printers are:

Laser Printers: These are the high speed printers in which a high intensity laser beam
is used to alter the electrical charge on a photoconductor drum. The drum is then rolled
through a toner powder which is picked up by the charged portion of the
drum. This toner powder is then shifted to the paper and fused permanently with the help
of heat and pressure. The speed of these printers can range from 10 to 20 ppm (pages per
minute).

Inkjet Printers: In these type of printers, the output is generated by spraying
extremely small droplets of ink onto the paper. The ink which is used in these contains
high iron contents which is sprayed from the print head nozzle after getting
electronically charged. These are slower than laser printers as they take 20-25 seconds
to print one page.
Thermal Printers: These are expensive printers which are used for high quality graphics and text
output. In these, the print head contains heating elements whose specifi c elements are heated to
produce image or characters on a special heat sensitive paper. The maximum speed can be upto
200 cps. These are widely used in fax machines, credit card machines, calculators, etc.

3D Printer

This printer is a computer-aided manufacturing device that creates three-dimensional
objects from a digital fi le. Artifi cial human limbs, produced by 3D printers, have been
successfully implanted through surgery.
3D Printer
Plotters

These are printer like output devices used to create large sized engineering and architectural drawings on papers
or polyester fi lms. The output produced by the plotters is of very high quality and they can produce color as
well as black and white output depending on the ink used in them. Plotters can be of four types: Flatbed Plotter,
Drum Plotter, Inkjet Plotter and Micrographic Plotter.

Flatbed Plotter Drum Plotter Inkjet Plotter Micrographic Plotter

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