Computer Basics

1. Computer Basics Lesson 5 - Output

2. What is Output? • Output is data that has been processed into useful form, now called Information. • Types of Output: • Hard copy: printed on paper or other permanent media • Soft copy: displayed on screen or by other non-permanent means

3. Categories of output • Text documents - reports, letters, etc. • Graphics - charts, graphs, pictures • Multimedia - combination of text, graphics, video, audio

4. Printer features • What is the job of a printer? • Put on paper what you see on your monitor. • Monitor screens and printers do not use the same formatting rules. • In the olden days of computers, the way something looked on the screen could be VERY different from how it would look when printed. • Nowadays we expect to see a WYSIWYG view (What You See Is What You Get), where you see almost exactly what the document will look like in print, while you are still working on it.

5. Printer speed • The speed of a printer is measured in: • cps   = characters per second • lpm   = lines per minute • ppm   = pages per minute • The faster the printing, the more expensive the printer.

6. Paper type • Continuous-Form Paper • Advantage: Don't need to put in new paper often. • Disadvantage: May need to separate the pages and remove the strips of perforations from the edges. • Single Sheet • Advantage: Can change to special paper easily, like letterhead, card stock, or envelopes. • Disadvantage: Must add paper more often.

7. Printer quality • Measured in dots per inch (dpi), this determines how smooth a diagonal line is when printed. • Professionals in graphics use 1200 to 2400 dpi printers. Draft quality on such a printer would be 600 dpi.

8. What will it print? • Typeface  - Set of letters, numbers, and special characters with similar design. • Styles - Bold, italic, underlined... • Size - Is measured in points. One point = 1/72 of an inch.

9. Important terms • Font - A complete set of letters, etc. in the same typeface, style, and size. • Graphics - Pictures add a lot to a document, but not all printers can print graphics. • Color - Printing in color takes longer, uses more expensive inks/toner, looks best on more expensive papers, but can add a lot to the quality of the output.

10. Printer size • Sometimes a printer takes up a lot of space. What are some questions to ask before buying one? • Where will you put it? • Is there enough space for the printer and for the blank paper and the printouts? • Where does the printed page wind up?

11. Cable connections • Serial cable - Sends data only 1 bit at a time. Printer can be up to 1000 feet away from the computer. • Parallel cable - Sends data 8 bits at a time. Printer must be within 50 feet of the computer. • USB cable - Printer must be within 5 meters (16.5 feet) of the computer, when connecting straight to the computer. • Oddly, Windows XP does not support spooling for a parallel connection to a printer. Spooling is what allows you to do other things on the computer while the printer is processing and printing the document.

12. Computer basics Lesson 5 – Output (cont.) Printer Types

13. Printer types • Impact Printer – strikes the paper and ribbon together to form a character, like a typewriter. • Advantages: • Less expensive • Fast (some types) • Can make multiple copies with multipart paper • Disadvantages:   • Noisy! • Print quality lower in some types. • Poor graphics or none at all.

14. Printer types • Dot Matrix - Forms characters using row(s) of pins, 9, 18, or 24 which impact the ribbon on top of the paper. Also called pin printers. • Advantages: • Inexpensive • Can do multi-copy forms • Disadvantages: • Can be slow • Loud • Graphics of low quality, if possible at all

15. Printer types • Chain and Band Printers - Uses characters on a band or chain that is moved into place before striking the characters onto the paper. • Advantage:  • Very fast - up to 3000 lpm • Disadvantages:  • Very expensive • Very loud

16. Printer types Non-Impact Printers • This type of printer does not involve actually striking the paper. Instead, it uses a spray of printer ink or else toner powder. • Advantages: • Quiet! • Can handle graphics and often a wider variety of fonts than impact printers. • Disadvantages:   • More expensive • Slower

17. Printer types Ink Jet • Sprays ink onto paper to form characters • Advantages:  • Quiet • High quality text and graphics. • Some can do color. • Disadvantages:  • Cannot use multiple-copy paper • Ink can smear

18. Printer types Thermal • Uses heat on chemically treated paper to form characters. Fax machines that use rolls of paper are also of this type. • Advantages:  • Quiet • Disadvantages:  • Relatively slow • Expensive, requiring special paper • Cannot use multiple-copy paper

19. Printer types Page Printer    • Works like a copy machine, using toner and a heat bar. Laser printers are in this category. • Advantages:  • Quiet • Faster than other non-impact printers, from 4 to 16 ppm (pages per minute) • High quality print and graphics. • Some can do color. • Disadvantages:  • More expensive than impact printers • Cannot use multiple-copy paper

20. Things to consider when choosing a printer…. • How much output? • What speed is needed? • Is heavy-duty equipment necessary? • Quality of output needed?  • Resolution needed • Photo quality? • Location of printer? • How big a footprint can be handled? • Is loudness important?

21. Things to consider when choosing a printer…. • Expense of ink or toner? • How much does a cartridge cost and how many pages will it produce? • How is that number measured? • Photo ink is more expensive! • Number of cartridges? • Just one 3-color cartridge or separate black and color cartridges or a cartridge for each color(best, if you can afford it!)

22. Computer basics Lesson 5 – Output (cont.) Screen Features

23. Screen features The device which displays computer output to us has various names: • Screen from "computer screen" or "display screen" . • Monitor   from its use as a way to "monitor" the progress of a program. • VDT = video display terminal  from early network terminals . • CRT = cathode ray tube   from the physical mechanism used for the screen.  • VDU = visual display unit  to cover all the mechanisms from desktop CRTs to LCD flat screens on laptops to LED screen on palmtops.

24. Lcd (liquid crystal display) • very flat and thin • made of two layers of a polarizing material with a liquid crystal solution in between • electrical signal to a cell makes the crystals line up • uses 3 colored subcells for each cell: Red, Green, and Blue

25. Crt (cathode ray tube) • screen is coated on the inside surface with dots of chemicals called phosphors • when a beam of electrons hits a dot, the dot will glow • phosphor dots are in groups of three: Red, Green, and Blue • A shadow mask blocks the path of the beams in a way that lets each beam only light its assigned color dots.

26. Screen features • Desktop screens are usually 15 - 23 in. by diagonal measurement. • Resolution - Determines how clear and detailed the image is. • Pictures on a screen are made up of tiny dots. • 1 dot on screen = 1 pixel (from "picture element"). • The more pixels per inch, the clearer and more detailed the picture. • Refresh Rate - How often the picture is redrawn on the monitor.

27. Screen features

28. Screen types • Monochrome - one color text on single color background, i.e. white letters on blue, or green characters on black. • Color - various colors can be displayed. • CRT - Formerly most common type of monitor, which uses a cathode ray tube. • Liquid Crystal Display (LCD) - Used in laptops esp. Large LCD monitors are the most common now. • Plasma Screens - Used for very large screens and some laptops. Flat, good color, but much more expensive.These have gone out of style.

29. Other devices • Data projectors - Projects the image onto a wall or screen. • Computer Output Microfilm - The computer directly generates the microfilm images. • Sound - Computers can output voice messages, music, data as sound. Of course you have to have speakers and a sound card.