Computer Output Devices
Computer hardware devices that facilitate dissemination of data and information into usable form are classified under the output device category.
Output hardware read information like text, graphics, video, sound and other digital outputs and present them visually, by sound and onto physical media for user consumption.
There are two major categories of data and information output:
As the words suggest, softcopy forms are not physical and can only be experienced visually or through sound. Hardcopy outputs that can be felt, touched and visualized.
Softcopy Output Devices
Softcopy output devices available in two forms:
- Display devices
- Sound devices
They take advantage of sight and hearing senses and are usually accompanied by physical computing devices. For example, you will need a personal computer to watch a movie output and an iPod to listen to your mp3 file.
1: Display Output Devices
Display output is probably the most common form of output. A visual display disseminates texts, graphics and video immediately they are required. Take the touch technology, for example, where input and output are experienced simultaneously.
You tap your smartphone screen to watch a movie or doodle using your finger and the results will be instant.
Popular display technology forms include:
- Computer monitor
- Projection display
- Electronic smartboard
A monitor is an electronic visual display device which outputs information in visual forms like texts, graphics and video. Examples of monitor types include:
- Cathode Ray Tube (CRT): a display unit of conical shape and uses electron gun to fire display onto the display tube. CRT screens offer better contrast ratios and viewing angles than LCD and LED technologies, but due to higher power consumption and unnecessarily extra space they take, CRTs have been abandoned by manufacturers.
- Liquid Crystal Display (LCD): LCDs are flat panels that use compact fluorescent light bulbs embedded with mercury to facilitate display. LCD offer better display in brighter rooms.
- Light Emitting Diode (LED): LED display are flat panels that use diodes to emit light for display to take place.
- Plasma: plasma screens are flat panels which use gasses made up of electrons and ions, and the movement of electrical current through the plasma gasses causes the atoms to release energy as light. Plasma screens are usually thicker in size and richer in color depth than LCD and LED, but will display washed out images in brighter rooms. They are commonly used as television sets than computer screens.
- Organic Light Emitting Diode (OLED): OLED screens are thinner than the rest and use organic material with carbon to convert the electric current into light. OLED screens are capable of separately lighting up each picture element unlike the LCD design. This makes OLED screens much brighter and colorful than LED screens.
HD, Ultra HD And 4K Monitors
Ultra high definition screens are still mostly targeted for television users. They are LED and LCD models which implement more than usual pixels onto the display.
4K screens have four times or more screen resolution (3,840 x 2,160 pixels) of traditional HD screens. This explains why they are much wider than traditional displays.
Projection display technology uses a projection device to beam visual display forms onto a physical background or augmented reality display.
A projector is an output device that connects and beams enlarged computer display onto a physical surface like a wall or canvas. They are commonly used for presentations and other kinds of meetings and workshops to help make displayed data larger for many attendees to view.
- Augmented Reality Display
Augmented Reality (AR) or computer mediated reality, involves the use of electronic display device to fool the eye and mind into seeing a much larger display than it actually is.
One such display is featured in Google Glass which uses LED illuminated display technology to beam larger display.
A smartboard is an interactive electronic whiteboard that was designed to take place or work in tandem with traditional whiteboards and chalkboards in education institutions. It can as well project desktop and other data of the computer it is plugged onto.
Unlike chalkboards and whiteboards which used chalk and specialized markers, smartboards are touch enabled, making it possible to input and view data and information right on the same surface. Apart from using the finger as input source, special inkless pens and other pointing device can be used on it.
2: Sound Output Devices
An audio or sound output (ASIO) device attaches to the sound card port in order to emit output that can be interpreted and heard by human ears.
There are two popular devices in use today for sound output:
Speakers allow you to listen to music and hear sound effects from the computer.
Speakers are built into the computer i.e. laptops and mobile devices, or standalone devices which connect to the computer by use of cable or wireless signals.
Headphone and Earphone
Headphones are head mounted in nature and are fitted around the head and ears where sound is most needed.
Earphones meanwhile are tiny little buds that plug directly inside the ear.
Headphones and earphones connect to computers via cable or Bluetooth wireless signal.
Hardcopy Output Devices
Hardcopy output devices disseminate data and information into forms that can be visualized and touched, but most importantly available independent of the output device and computer.
The printer is the most common hardcopy output device.
A printer is a peripheral device which receives and converts text and artwork onto paper or 3D form. Several printer technologies exist in the market today,
- Impact printers
- non-impact printers
- Another more recent printer technology creates 3D models as its printout
1: Impact Printers
Impact printers make direct physical contact with the paper it is printing onto. Two types of impact printers have been around us for long. They are:
- Daisy wheel printers
- Dot matrix printers
Daisy wheel printers are rarely in use today, but a number of institutions and offices still use Dot matrix printers.
Dot matrix Printer
A dot matrix printer uses a row of pins through an ink ribbon onto paper, and the quality of the printout is determined by the number of available pins. Printers with more pins will definitely printer copies. Most dot matrix printers have 24 pins. Dot matrix printers are called so because of the printed characters that are formed by a matrix of dots during printing.
These printers however, generate a lot of noises and do not produce high quality work. Dot matrix printers are commonly used by companies in printing pay slips and receipts, where quality is not a priority. An example of this type of printer is Epson LX300.
2: Non Impact Printers
In non impact printers, there is no physical contact between the printing mechanism and paper.
Inkjet printers operate by spraying small drops of ink onto paper. Inkjet printers are the most common type of printers, due to its low cost, fair printing quality and color printing. They also make less noise as compared to impact printers.
Though cheaper to buy, the print per page cost in an inkjet printer is much higher, and the print speed is not as fast as in laser jets.
A laserjet printer produces high quality printouts than the rest of personal printers. Laser stands for light amplification by simulated emission of radiation.
Laserjets use laser technology and toner to send information onto paper. Toner in a laser printer is a powder material.
A laser beam projects an image onto a rotating drum. The drum then prints the image onto paper by using direct heat and fusing the ink to paper.
Laserjet printers either ship in monochrome or color. Besides the black toner cartridge in a monochrome printer, the color laserjet printer has three other cartridges with the colors, cyan magenta and yellow.
A thermal printer prints by heating regions of heat waxy paper. The image is created on the waxy paper by burning dots on it. For coloured output, coloured waxy sheets are used.
Thermal printers are commonly used in cash registers and ATMs.
3: 3D Printers
3D printing also known as desktop fabrication is the process of making three dimensional solid objects from a 3D model in the computer.
To create 3D models, you will need to draw models using design software or assemble and stitch a set of 3D images. 3D files are saved in .stl file format and then sent to the printer.
The concept of printing a three dimensional object using a 3D printer is actually similar to basic printing using inkjet printers.
Technically, the printout object is created when layers of liquid print material is deposited on print surface till the desired 3D solid object is achieved. Unlike the impact and non impact printing mentioned above, 3D printing works by additive procedures though.
Even so, 3D printing varies from printer to technology, with some printouts modeled out of melted materials, and others from special paper.
Other Printer Technology
- Solid printers
- Label printer
- Wide format printer
- Dye sublimation printer
- Braille printer
Cloud printing is another big leap in cloud services. A technology championed by Google, cloud printing permits printing beyond borders.
A Google account can be configured to install and prepare a Google cloud printer or any standard local printer to be used across the internet.
What this means is that you can set up your local printer in London and print your work using another computer when in Kampala or Tokyo, right within your Gmail account.
Cloud printing is even more convenient if you wish to print a document right from your mobile phone. Google cloud printing supports both Android and IOS.
Are you a regular user of cloud printing?
Other Output Devices
- Paper printer
- Photo printer