PRINTERS

~Printer is used to translated information processed by system unit and present the information on paper. Output from printers is described as hard copy.

FEATURES :

Four basic features:

üResolution

• A measurement of clarity of images produced.

• Measured in dpi( dots per inch). Higher the dpi, better the quality images produced.

üColour capability

• Printers contain black ink or colour ink.

• Colour is used more selectively of report containing graphics and photographs.

üSpeed

• Measured in number of pages printed per minute.

•Single-colour (black) output, 15 to 19 per minute. 13  to 15 pages per minute for colour output.

üMemory

•Used to store printing instructions and documents waiting to be printed.

• The more memory, the faster to create large documents.

It have 4 types of printers :

(1) INK-JET PRINTERS :

-- Although inkjets were available in the 1980s, it was only in the 1990s that prices dropped enough to bring the technology to the high street.
-- A type of printer that works by spraying ionized ink at a sheet of paper.
-- Producing high quality print approaching that produced by laser printers.
-- A typical ink-jet printer provides a resolution of 300 dots per inch, although some newer models offer higher resolutions.

-- Most widely used because:

i.Reliable

ii.Quite

iii.Inexpensive

-- Typical ink-jet printers produce 17 to 19 pages  per minute(black). 13 to 15 pages per minute(colour)

-- For more information, please refer to http://www.webopedia.com/TERM/I/ink_jet_printer.html , http://www.pctechguide.com/53Inkjets.htm

      http://www.desktopclass.com/education/computer-it/what-is-non-impact-printer-discuss-its-different-types.html

(2) LASER PRINTERS :

-- A laser printer is a common type of computer printer that rapidly produces high quality

text and graphics on plain paper.

-- In comparison with the laser printer, most inkjet printers and dot-matrix printers simply

take an incoming stream of data and directly imprint it in a slow lurching process.

-- A laser printer is unable to work this way because such a large amount of data needs to

output to the printing device in a rapid, continuous process.

-- The printer cannot stop the mechanism precisely enough to wait until more data arrives,

without creating a visible gap or misalignment of the dots on the printed page.

-- Laser printers use laser light beam to produce excellent letter and graphics quality images.

It is:

i.More expensive than ink-jet printers

ii.Faster

iii.Used in applications requiring high-quality output.

Another Two categories:

Personal laser printers

§Do not support colour

§Less expensive

§Used by many single player

Shared laser printers

§Support colour

§More expensive

§Used by a group of users

  Shared laser printers typically print over 50 pages a minute

-- For more information, please refer to http://en.wikipedia.org/wiki/Laser_printer

http://www.gadgetvenue.com/samsung-ml-1630-sleek-laser-printer-12222730/

(3) THERMAL PRINTERS :

§Uses heat elements to produce images on heat-sensitive paper.

§Widely used with ATMs and gasoline pumps to print receipts.

§Thermal printers print more quietly and usually faster than impact dot matrix printers.

§They are also smaller, lighter and consume less power, making them ideal for portable and retail applications.

§A thermal printer comprises these key components:

(4) OTHER PRINTERS :

 

Dot-matrix Printers

--Form characters and images using a series of small pins on a printer head.

It is:

I.Inexpensive

II.Quite noisy

Used in task where high-quality output is not required.

--Advantage : The ink ribbon also does not easily dry out, including both the ribbon stored in

the casing as well as the portion that is stretched in front of the print head; this unique
property allows the dot-matrix printer to be used in environments where printer duty can be
rare, for instance, as with a Fire Alarm Control Panel's output.
--For more information, please refer to http://en.wikipedia.org/wiki/Dot_matrix_printer

                                                     http://www.jestineyong.com/?p=2711

Plotters

--Used to produce a wide range of specialized output.

--Plotters used to create:

I.Maps

II.Images

III.Architectural

IV.Engineering drawings

--For more information, please refer to http://en.wikipedia.org/wiki/Plotter  
 
http://www.supplierlist.com/products/category/1003/100328/p-30/Machinery_for_Paper_Wood_and_Furniture.htm
  As my opinion, i think we as a student are more prefer to use laser printer. It is because it is
more easier and convinient are use in printing. This printer have white and black colour, also
have variety of colour. The price are cheaper than other kinds of printer.

Citations:
- http://www.webopedia.com/TERM/I/ink_jet_printer.html , http://www.pctechguide.com/53Inkjets.htm
- http://en.wikipedia.org/wiki/Laser_printer

- http://en.wikipedia.org/wiki/Thermal_printer

- http://en.wikipedia.org/wiki/Dot_matrix_printer

- http://en.wikipedia.org/wiki/Plotter  
-  http://www.sony.com.my/productcategory/di-dpp-photo-printer
-  http://www.smallportableprinter.com/

Photo Printers

§Special-purpose printers designed to print photo-quality images from digital cameras.

§Print 3x5’ or 4x6’ images on glossy, photo-quality paper.
§For more information, please refer to http://www.sony.com.my/productcategory/di-dpp-photo-printer

                                                      http://dutechs.com/products.html

Portable Printers

§Small and lightweight printers( designed to work with notebook computers)

§It may be ink-jet or laser printers

§Print in black and white or colour

§Connect with USB or parallel port connections

§Reduce the power and the features, while raising the price on the product.

§For more information, please refer to http://www.smallportableprinter.com/

                         http://www.coolest-gadgets.com/20080414/canon-pixma-ip100-portable-printer/

• Thermal head — generates heat; prints on paper
• Platen — a rubber roller that feeds paper
• Spring — applies pressure to the thermal head, causing it to contact the thermo-sensitive paper
• Controller boards — for controlling the mechanism

--For more information, please refer to http://en.wikipedia.org/wiki/Thermal_printer

                                                                 http://ean128.co.uk/

CHAPTER 8 = SECONDARY STORAGE

SECONDARY STORAGE 

•        Secondary storage devices are used to save, to back up, and even to transport files consisting of data or programs from one location or computer to another. 

•        Secondary storage devices have always been an indispensable element in any computer system.

•         Secondary storage provides permanent or nonvolatile storage.

•       Some important characteristics of secondary storage include:

1.     Media are actual physical material that holds the data and program.

2.     Capacity measure how much a particular storage medium can hold.

3.     Storage devices are hardware that reads data and programs from storage media.

4.     Access speed measure the amount of time required by the storage device to retrieve data and program. 

 

HARD DISKS

• A hard disk drive (HDD) is a non-volatile , random access device for digital data. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the platters. 

• Introduced by IBM in 1956, hard disk drives have fallen in cost and physical size over the years while dramatically increasing in capacity. Hard disk drives have been the dominant device for secondary storage of data in general purpose computer since the early 1960s. They have maintained this position because advances in their areal recording density have kept pace with the requirements for secondary storage. Today's HDDs operate on high-speed serial interfaces; i.e., serial ATA (SATA) or serial attached SCSI  (SAS).           

Components  

• A typical hard disk drive has two electric motors; a disk motor to spin the disks and an actuator (motor) to position the read/write head assembly across the spinning disks.

• The disk motor has an external rotor attached to the disks; the stator windings are fixed in place.   

• For more information refers to http://en.wikipedia.org/wiki/Hard_disk_drive     

INTERNAL HARD DISK   

• It is located inside the system units. 
• The are designated as C drive. 
• Are able to storage and retrieve large quantities of information quickly. 
• Used to storage program and large data files.                                                
    
   
  http://www.blogger.com/goog_227295440
  
  
  EXTERNAL HARD DRIVE     
  • Provide fast access, they have a fixed amount of storage and cannot be easily removed from the system cabinet. 
  • Typically connect to a USB or FireWire port on the system unit, are easily removed and effectively provide an unlimited amount of storage. 
  • For desktop computers have typically capacities of 20 to 500 GB. 
  •   Credit card-size hard disks cartridges called PC Card hard disks are available for notebook computers with typically capacities up to 5 GB.

 

http://www.build-your-own-computer.net/external-hard-drive.html

Secondary storage are important because can be used to restore a backup of your files if you have to format. It also can be bring it with you if you need to access files at work or somewhere else. Without secondary storage you would lose all of you data every time your computer powered down. In order words , your computer would not have anywhere to save data indefinitely. For more information you can refers to http://wiki.answers.com/Q/Why_secondary_storage_devices_are _important.                                                                                                                            

Citation ~ http://wiki.answers.com/Q?Why_secondary_storage_devices_are_important.       

~http://en.wikipedia_org/wiki/Hard_disk_drive                                       

~Computing Essentials 2010 Books