CHAPTER-7 UNDERSTANDING OUTPUT

What is output ?

Output is data that has been processed into a useful form. An output device is any type of hardware component that conveys information to one or more people.

A display device visually conveys text, graphics, and video information. A monitor is packaged as a separate peripheral

• ·    LCD monitor - Liquid crystal display (LCD) uses a liquid compound to present information on a display device. LCD monitors use a digital signal and should plug into a DVI port, an HDMI port, or a Display Port. 
• ·       Widescreen - Televisions also are a good output device. Require a converter if you are connecting your computer to an analog television. Digital television (DTV) offers a crisper, higher-quality output. HDTV is the most advanced form of digital television
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Resolution is the number of horizontal and vertical pixels in a display device. A higher resolution uses a greater number of pixels.

 Plasma monitors are display devices that use gas plasma technology and offer screen sizes up to 150 inches

CRT - A CRT monitor is a desktop monitor that contains a cathode-ray tube.

A printer produces text and graphics on a physical medium. Printed information is called a hard copy, or printout landscape or portrait orientation.

How does laser printer work :-

Laser printers are a lot like photocopiers and use the same basic technology. Indeed, as we describe later in this article, the first laser printers were actually built from modified photocopiers. In a photocopier, a bright light is used to make an exact copy of a printed page. The light reflects off the page onto a light-sensitive drum; static electricity (the effect that makes a balloon stick to your clothes if you rub it a few times) makes ink particles stick to the drum; and the ink is then transferred to paper and "fused" to its surface by hot rollers. A laser printer works in almost exactly the same way, with one important difference: because there is no original page to copy, the laser has to write it out from scratch.

How does inkjet work :-

The information you store is in electronic format: each piece of data is stored electronically by a microscopically small switching device called a transistor. The printer's job is to convert this electronic data back into words and pictures: in effect, to turn electricity into ink. With an inkjet printer, it's easy to see how that happens: ink guns, operated electrically, fire precise streams of ink at the page. With a laser printer, things are slightly more complex. The electronic data from your computer is used to control a laser beam—and it's the laser that gets the ink on the page, using static electricity in a similar way to a photocopier.

An ink-jet printer forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper. Color or black-and-white. Printers with a higher dpi (dots per inch) produce a higher quality output.

A multifunction peripheral (MFP) is a single device that prints, scans, copies, and in some cases, faxes. Sometimes called an all-in-one device

A thermal printer generates images by pushing electrically heated pins against the heat-sensitive paper . For example – Thermal wax transfer printer.

An audio output device produces music, speech, or other sounds.

Headphones are speakers that cover or are placed outside of the ear

Earbuds (also called earphones) rest inside the ear canal.

A data projector is a device that takes the text and images displaying on a computer screen and projects them on a larger screen :-

• ·       LCD projector
• ·       Digital light processing (DLP) projector
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 Plotters are used to produce high-quality drawings.

Large-format printers create photo-realistic quality color prints on a larger scale.

Mobile printer :-

A mobile printer is a small, lightweight, battery-powered printer that allows a mobile user to print from a notebook computer, smart phone, or other mobile devices.

Label printer :-

A label printer is a small printer that prints on adhesive-type materials.

A postage printer prints postage stamps :-

Postage also can be printed on other types of printers.

How black and white laser printer work :-

·                      Millions of bytes (characters) of data stream into the printer from your computer.

      An electronic circuit in the printer (effectively, a small computer in its own right) figures out how to print this data so it looks correct on the page.
 
 
·        The electronic circuit activates the corona wire. This is a high-voltage wire that gives a static electric charge to anything nearby.
 
·        The corona wire charges up the photoreceptor drumso the drum gains a positive charge spread uniformly across its surface.
 
 
·        At the same time, the circuit activates the laser to make it draw the image of the page onto the drum. The laser beam doesn't actually move: it bounces off a moving mirror that scans it over the drum. Where the laser beam hits the drum, it erases the positive charge that was there and creates an area of negative charge instead. Gradually, an image of the entire page builds up on the drum: where the page should be white, there are areas with a positive charge; where the page should be black, there are areas of negative charge.
 
·        An ink roller touching the photoreceptor drum coats it with tiny particles of powdered ink (toner). The toner has been given a positive electrical charge, so it sticks to the parts of the photoreceptor drum that have a negative charge (remember that opposite electrical charges attract in the same way that opposite poles of a magnet attract). No ink is attracted to the parts of the drum that have a positive charge. An inked image of the page builds up on the drum.
 
 
·        A sheet of paper from a hopper on the other side of the printer feeds up toward the drum. As it moves along, the paper is given a strong positive electrical charge by another corona wire.
 
·        When the paper moves near the drum, its positive charge attracts the negatively charged toner particles away from the drum. The image is transferred from the drum onto the paper but, for the moment, the toner particles are just resting lightly on the paper's surface.
 
 
·        The inked paper passes through two hot rollers (the fuser unit). The heat and pressure from the rollers fuse the toner particles permanently into the fibers of the paper.
 
·        The printout emerges from the side of the copier. Thanks to the fuser unit, the paper is still warm. It's literally hot off the press.