Devices that output Hardcopy
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Dot matrix printers use pins to strike an ink ribbon and transfer ink to paper, forming characters and images from arrangements of dots. They provide low-cost printing but also low resolution and quality. Laser printers use heat and pressure to bond toner particles to paper in the pattern of an image formed by a laser beam scanning a photosensitive drum. They offer higher quality printing than inkjet printers. Printers can be categorized as either impact printers that use a mechanism to transfer ink, like dot matrix, or non-impact printers like inkjet and laser that use other ink transfer methods.
Devices that output Hardcopy
- 1. Devices that Output Hard Copy
- 2. 2 What is a printer? An external hardware device responsible for taking computer data and generating a hard copy of that data. Printers are one of the most commonly used peripherals and they print text and still images on the paper.
- 3. 3 Printers Impact Printers Non-Impact Printers Daisy wheel Dot- Matrix Inkjet Thermal Laser
- 4. Categorizing Printers 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.
- 5. 5 “Factors affecting print quality” (1) DPI: It is a measurement of printer’s resolution indicating how many ink dots can be placed by the printer in one square inch. The higher the DPI, the sharper is image. Image quality – Measured in dots per inch (dpi). Most printers produce 300 – 1200 dpi. (2) Type of printer: Each type of printer has its own capabilities of printing. Some types of printers produce high quality print while other produce low quality print. (3) Print Mode: The printing mode may also affect the quality. For example the draft mode increases the print rate but quality is reduced. (4) Toner: The quality and amount of toner also affects print quality.
- 6. Dot Matrix Printers • How Do Dot Matrix Printers Work? • Performance
- 7. 7 “Dot Matrix Printer” • The term dot matrix refers to the process of placing dots to form an image. • Its speed is usually 30 to 550 characters per second (cps). • This is the cheapest and the most noisy printer and has a low print quality. Dot Matrix were 1st introduced by Centronics in 1970.
- 8. 8 How Dot-Matrix works? • The dot matrix forms images one character at a time as the print head moves across the paper. • Uses tiny pins to hit an ink ribbon and the paper much as a typewriter does. • This printer arranges dots to form characters and all kinds of images. • 9 to 24 vertical column pins are contained in a rectangular print head. When print head moves across the paper, pins are activated to form a dotted character image. These printers can produce carbon copies along with the originals.
- 10. 10 “A typical dot matrix output”
- 11. Dot Matrix Printers - Performance • 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.
- 12. 12 “Advantages/Dis-advantages of Dot-Matrix” • Advantages: • (1) In-expensive. • (2) Low per page cost. • (3) Energy efficient. • Dis-advantages: • (1) Noisy • (2) Low resolution • (3) Limited fonts flexibility • (4) Poor quality graphics output.
- 13. 13 “Daisy Wheel Printer” • A daisy wheel printer is basically an impact printer consisting of a wheel and attached extensions on which molded metal characters are mounted. A daisy wheel printer produces letter quality print and it can’t produce graphics output.
- 14. 14 How Daisy wheel printer works? • In a daisy wheel printer, a hammer presses the wheel against a ribbon which in turn makes an ink stain on the paper in the form of a character mounted on the wheel extensions. • These printers are very noisy as there occur great movement during the printing. Its printing speed is also very slow ,i.e. less than 90cps.
- 15. Ink Jet Printers • How Do Ink Jet Printers Work? • Performance
- 16. Ink Jet Printers – 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.
- 17. “Ink-Jet Printer” • A standard Inkjet printer has a resolution of 300dpi.
- 19. How Inkjet Printer works? • (1) Print head having four ink cartridges moves . • (2) Software instructs where to apply dots of ink, which color and what quantity to use. • (3) Electrical pulses are sent to the resistors behind each nozzle. • (4) Vapor bubbles of ink are formed by resistors and the ink is forced to the paper through nozzles. • (5) A matrix of dots forms characters and pictures. Color cartridge showing inkjet nozzles.
- 20. Ink Jet Printers - Performance 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.
- 21. Advantages/ Dis-advantages Advantages: (1) High resolution output. (2) Energy efficient. (3) Many options to select. Dis-advantages: (1) Expensive. (2) Special paper required for higher resolution output. (3) Time consuming in case of graphics printing.
- 22. Laser Printers • How Do Laser Printers Work? • Performance
- 24. 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.
- 25. How Laser printer Works? • (1) Paper is fed and the drum rotates. • (2) A laser beam conveys information from the computer to a rotating mirror and thus an image is created on the drum. • (3)The charges on the drum are ionized and the toner sticks to the drum. • (4)Toner is transferred from drum to paper. • (5)Heat is applied to fuse the toner on the paper.
- 27. Laser Printers - Performance • 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.
- 28. 28 Thermal Printer • Thermal printers are in- expensive printers mostly used in fax machines. The Thermal printers are further classified into two types. • (1) Electro thermal printers: • (2) Thermal Wax printers: A fax machine using a thermal printer
- 29. 29 “Multi-function printer” • A multi function printer abbreviated as MFP is an all purpose device that prints, faxes, copies and scans. A single multi function printer can replace several bulky devices. A multi function printer is also known as AIO. These printers use inkjet technology and provide high quality print but at slow speed.
- 30. 30 “Plotter” • A large scale printer which is very accurate in producing engineering drawings and architectural blueprints. • Two types of plotters are flatbed and drum. • Flatbed plotters are horizontally aligned while drum plotters are vertically positioned.
- 31. Snapshot Printers • Snapshot printers are specialized, small-format printers that print digital photographs. • Snapshot printers are fairly slow, and can be more expensive to operate
- 33. Other High-Quality Printers Print shops and publishers use these printers to create high-quality color images: • Thermal-wax • Dye-sublimation • Fiery • IRIS • Plotters
- 34. Plotters use mechanical, ink jet, or thermal technology to create large-format images for architectural or engineering uses.
- 35. lesson Review • List the three most commonly used types of printers. • List the four criteria you should consider when evaluating printers. • Describe how a dot matrix printer creates an image on a page. • Explain the process by which a laser printer operates. • List five types of high-quality printing devices commonly used in business.