- Printers fall into two categories:
Impact printers use a device to strike an inked ribbon, pressing ink from the ribbon onto the paper.
Non-impact printers use different methods to place ink (or another substance) on the page.
How Do Dot Matrix Printers Work?
- Dot matrix printers are a common type of impact printer.
- A dot matrix printer's print head contains a cluster of pins. The printer can push the pins out to form patterns in rapid sequence.
- The pins press an inked ribbon against the paper, creating an image.
- Lower-resolution dot matrix printers use nine pins. Higher-resolution models have 24 pins.
- Speed is measured in characters per second (cps). Some dot matrix printers print 500 cps.
How Do Ink Jet Printers Work?
- Ink jet printers are an example of non-impact printers.
- The printer sprays tiny droplets of ink onto the paper.
Ink jet printers are available for color and black-and-white printing.
Ink jet printers offer speeds of (2 – 4 pages per minute ppm) and resolution (300 – 600 dots per inch dpi), comparable to low-end laser printers.Ink jet printers are inexpensive and have low operating costs.
Laser Printers –
How Do Laser Printers Work?
- Laser printers are non-impact printers.
They use heat and pressure to bond particles of toner to paper.
Laser printers are available for color and black-and-white printing.
- Laser printers provide resolutions from 300 – 1200 dpi and higher.
- Black-and-white laser printers usually produce 4 – 16 ppm.
Laser printers produce higher-quality print than ink jet printers, but are more expensive.
Laser Printers - Performance
Overview of Printers - Evaluating Printers
When evaluating printers, consider four criteria:
Image quality – Measured in dots per inch (dpi). Most printers produce 300 – 600 dpi.
Speed – Measured in pages per minute (ppm) or characters per second (cps)
Initial cost – Consumer printers cost $250 or less, but professional printers can cost thousands of dollars.
Cost of operation – This refers to the cost of supplies used by the printer.
Photo printers
1.Used to print images that can be created by using Digital camera or scanner.
Thermal – Wax printer
1.Presentation Graphics and handouts
2.Bold colors with heavy color requirement, posters or book covers
3.Ribbon coated with panels of colored Wax that melts and adheres to plain paper as colored dots when passed over a focused heat source.
Dye – Sublimation printers
1.Get Realistic quality and color for photo images- Desktop publishers, artist
2.Ribbon containing panels of color is moved across a focused heat source
3.Capable of subtle temperature variations.
4.The heated dyes evaporated from the ribbon and diffuse on specially coated paper .
5.The variation to the color are related to the intensity of the color applied.
6.Create sharp images. Slow.
Plotters
1.Same like printer except that it is used to print large format images – construction drawings created by an architect.
2.Early plotter : Mechanical device contains robotic arm used to draw images on paper
4.Two arms operating at right angles as they draw on a stationary paper
5.Large and complex table plotters are notoriously slow
6.Large complicated drawings can take several hours to print
Roller plotter – Drum plotter
1.one drawing arm but moves the paper
2.The drawing arm moves side to side as the paper is rolled back and forth
3.Draw perfect circles and other geometric shapes.
4.Mechanical plotters replaced by Thermal, electro static, ink jet plotters and dye – sub printers.
5.These devices can also produces large size drawings are faster and cheaper than mechanical plotters
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