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NETWORK BASICS

Network A system of interconnected computers and computerized peripherals such as printers is called computer network. This interconnection among computers facilitates information sharing among them. Computers may connect to each other by either wired or wireless media. A computer network consists of a collection of computers, printers and other equipment that is connected together so that they can communicate with each other.  


Network application
A Network application is any application running on one host and provides a communication to another application running on a different host, the application may use an existing application layer protocols such as: HTTP(e.g. the Browser and web server), SMTP(e.g. the email-client). And may be the application does not use any existing protocols and depends on the socket programming to communicate to another application. So the web application is a type of the network applications. 
There are lots of advantages from build up a network, but the th…

PRINTER & SCANNER

PRINTER & SCANNER
A printer is an electromechanical device which converts the text and graphical documents from electronic form to the physical form. Generally they are the external peripheral devices which are connected with the computers or laptops through a cable or wirelessly to receive input data and print them on the papers.  A wide range of printers are available with a variety of features ranging from printing black and white text documents to high quality colored graphic images. Quality of printers is identified by its features like color quality, speed of printing, resolution etc. Modern printers come with multipurpose functions i.e. they are combination of printer, scanner, photocopier, fax, etc. To serve different needs there are variety of printers available that works on different types of technologies. Printer is the most popular output device used today to produce hard copy output. There are many types of printers which are used by the users as according to their need. 

Printer Characteristics

Printers are also classified by the following characteristics:

Quality of type The output produced by printers is said to be either letter quality (as good as a typewriter), near letter quality, or draft quality. Only daisy-wheel, ink-jet, and laser printers produce letter-quality type. Some dot-matrix printers claim letter-quality print, but if you look closely, you can see the difference. 

Speed Measured in characters per second (cps) or pages per minute (ppm), the speed of printers varies widely. Daisy-wheel printers tend to be the slowest, printing about 30 cps. Line printers are fastest (up to 3,000 lines per minute). Dot-matrix printers can print up to 500 cps, and laser printers range from about 4 to 20 text pages per minute. 

Impact or non-impact: Impact printers include all printers that work by striking an ink ribbon. Daisy-wheel, dot-matrix, and line printers are impact printers. Non-impact printers include laser printers and ink-jet printers. The important difference between impact and non-impact printers is that impact printers are much noisier. 

Graphics Some printers (daisy-wheel and line printers) can print only text. Other printers can print both text and graphics. 

Fonts Some printers, notably dot-matrix printers, are limited to one or a few fonts. In contrast, laser and ink-jet printers are capable of printing an almost unlimited variety of fonts. Daisy-wheel printers can also print different fonts, but you need to change the daisy wheel, making it difficult to mix fonts in the same document.

Types of Printers

Since the invention of the printing technology, a variety of technologies have been employed in computer printers. Broadly printers are categorized as impact and non-impact printers.

Impact printers are the type of printers in which a key strikes the paper to make a letter. The examples of Impact printers are Daisy wheel and Dot matrix printers. While non-impact printers do not operate by striking a head against a ribbon. Inkjet printers and laser printers are the non-impact printers. The most popular printers are described below.

Impact printers

An impact printer makes contact with the paper. It usually forms the print image by pressing an inked ribbon against the paper using a hammer or pins. Following are some examples of impact printers.

➣ Character Printer(Obsoleted Version)
Printer that stores individual characters when needed to print. A character printer will print one character at a time instead of one line at a time. Today, these printers are rarely used because of speed issues and because only text is capable of being printed.

➣ Line Printers (Obsoleted Version) Line Printer can Print One Line at a Time. The line printer is a form of high speed impact printer. They can Print 300 to 3000 Lines per Minute. So that they are very fast. Large Computer system typically use Line Printer.

The Line Printers are of two Types a) Drum Printer & b) Chain Printer

a) Drum Printers Drum Printer consists of a Drum Which Consists of a Number of Characters; those are Printed on the Drum. And the Number of Characters or Number of Tracks are Divided, after examining the width of the Paper. But there are also Some Character sets Available Means the Number of Characters those are printed on the Paper. For Example 64, and 96 Characters etc. In this Paper is placed between the Ribbon and the Head or Hammer there are many hammers on the Front of Drum. In this Drum Rotates at a Very High Speed and character is printed by activating the Appropriate Hammer. So always remember that All the Characters are never printed at a Time but they are printed at a very high Speed. And they can print only a Pre-Defined Styles because the Drum has a Specific Characters. Those are placed on the Drum. So that they can’t print the various Types of Fonts and Color Pictures. And Drum Printers are also noisy because they use Hammering Techniques. 

b) Chain Printers These are also Line Printers, which Prints one Line at a Time. All the    Characters are printed on the Chain and the Set of Characters are placed on the Chain. There are 48 and 64 and 96 Characters set Printers are Available. There are also Some Hammers, those are placed in Front of the Chain, and Paper is placed between the Hammer and the Inked Ribbon. The Total Number of Hammers will be Equals to the Total Number of Print Positions. In this Chain Rotates at a Very High Speed and Character is printed by activating the Appropriate Hammer of the Character. Chain Printers can also print some Pre-Defined characters and we can’t Display the High Quality of Fonts and Font Styles. They are also Impact Printers and Also Noisy because they Prints the Characters by Hammering Action. And these Printers can print the 400 to 3000 Lines per Minute.

Daisy Wheel Printers

Daisy wheel printers print only characters and symbols and cannot print graphics. They are generally slow with a printing speed of about 10 to 75 characters per second. By 1980 daisy wheel printers were the dominant printers for quality printing but since the prices of laser and inkjet printers have declined and quality of dot matrix printers has been improved, the daisy wheel printers are now obsolete.  Working of daisy wheel printers is very similar to typewriters. A circular printing element (known as daisy wheel, shown in the below image) is the heart of these printers that contains all text, numeric characters and symbols mound on each petal on the circumference of the circle. The printing element rotates rapidly with the help of a servo motor and pauses to allow the printing hammer to strike the character against the paper. 

Advantages 

1. Low maintenance 
2. Low costs 
3. Can create carbon copies 
4. Can use fan-fold paper and heavy paper grades 
5. Better print quality than a dot-matrix printer 

Disadvantages

1. Noisy printing 
2. No graphics 
3. Limited number of characters/types 
4. The character set is changed by replacing the daisy wheel 

Daisy wheel printing Technology

DOT MATRIX PRINTER

The dot-matrix printer uses print heads containing from 9 to 24 pins. These pins produce patterns of dots on the paper to form the individual characters. The 24 pin dot-matrix printer produces more dots that a 9 pin dot-matrix printer, which results in much better quality and clearer characters. The general rule is: the more pins, the clearer the letters on the paper. The pins strike the ribbon individually as the print mechanism moves across the entire print line in both directions, i-e, from left to right, then right to left, and so on. The user can produce a color output with a dot-matrix printer (the user will change the black ribbon with a ribbon that has color stripes). Dot-matrix
printers are inexpensive and typically print at speeds of 100-600 characters per second. Dot Matrix printer are normally haves slow printing speeds ranging from 30-600 characters per second. They are available at very low cost. These types of printers are generally used to print the shipping invoices.

Advantages

1. The Dot matrix printers are cheap and easily available in the market. 
2. They can make carbon copies of the print out unlike non-impact printers.
3. The printing costs are the lowest as compared to other printers.
4. The printout fades gradually rather than coming to a halt suddenly. You therefore get plenty of time to change the ribbon before crisis emerges.
5. They use paper continuously unlike other printers that require frequent change of paper. 
6. The maintenance cost is low as compared to other printers.
7. They tolerate dirty and hot conditions as are found in industrial environments.

Disadvantages 

1. The output is not high resolution. Color printout is limited and the print speed is also lesser as compared to non-impact printers. Therefore, the quality of print out in general is not very good. This affects the scanner readability of the print out.
2. The printer creates great deal of noise while the pins strike the ribbon to the paper.
3. The pins get bended easily destroying the print head.
4. The single sheet of paper has to wound and aligned by hand which is time-consuming and hectic. This also makes it prone to jamming frequently. Although paper jamming can happen with any printer, fixing it here is not an easy task.
5. The density of bar-codes is low and may fail to match user’s standards.

Non-impact printers

Non-impact printers do not use a striking device to produce characters on the paper; and because these printers do not hammer against the paper they are much quieter. Following are some non-impacted printers.

Ink-jet printers

Inkjet printing, like laser printing, is a non-impact process. Ink is emitted from nozzles while they pass over media. The operation of an inkjet printer is easy to visualize: liquid ink in various colors being squirted onto paper and other media, like plastic film and canvas, to build an image. A print head scans the page in horizontal strips, using the printer's motor assembly to move it from left to right and back again, while the paper is rolled up in vertical steps, again by the printer. A strip (or row) of the image is printed, then the paper moves on, ready for the next strip. 
To speed things up, the print head doesn’t print just a single row of pixels in each pass, but a vertical row of pixels at a time. For most inkjet printers, the print head takes about half a second to print the strip across a page. On a typical 8 1/2"-wide page, the print head operating at 300 dpi (dot per inch) deposits at least 2,475 dots across the page. 

This translates into an average response time of about 1/5000th of a second. Quite a technological feat! In the future, however, advances will allow for larger print heads with more nozzles firing at faster frequencies, delivering native resolutions of up to 1200dpi and print speeds approaching those of current color laser printers (3 to 4 pages per minute in color, 12 to 14ppm in monochrome). In other words, declining costs for improving technology. There are several types of inkjet printing. The most common is "drop on demand" (DOD), which means squirting small droplets of ink onto paper through tiny nozzles; like turning a water hose on and off 5,000 times a second. The amount of ink propelled onto the page is determined by the print driver software that dictates which nozzles shoot droplets, and when.

The nozzles used in inkjet printers are hairbreadth fine and on early models they became easily clogged. On modern inkjet printers this is rarely a problem, but changing cartridges can still be messy on some machines. Another problem with inkjet technology is a tendency for the ink to smudge immediately after printing, but this, too, has improved drastically during the past few years with the development of new ink compositions. In the inkjet printing mechanism, the print head has several tiny nozzles, also called jets. As the paper moves past the print head, the nozzles spray ink onto it, forming the characters and images. An inkjet printer can produce from 100 to several hundred pages, depending on the nature of the hard copy, before the ink cartridges must be replaced. There is usually one black ink cartridge and one so-called color cartridge containing ink in primary pigments (cyan, magenta, and yellow). Some inkjet printers use a single cartridge with cyan, magenta, yellow, and black ink. A few models require separate cartridges for each primary pigment, along with a black ink cartridge. 

One or more nozzles in the print head emit a steady stream of ink drops. Droplets of ink are electrically charged after leaving the nozzle. The droplets are then guided to the paper by electrically charged deflecting plates [one plate has positive charge (upper plate) and the other has negative charge (lover plate)]. A nozzle for black ink may be all that’s needed to print text, but full-color printing is also possible with the addition of needed to print text, but full-color printing is also possible with the addition three extra nozzles for the cyan, magenta, and yellow primary colors. If a droplet isn’t needed for the Character or image being formed, it is recycled back to its input nozzle. Several manufacturers produce color ink-jet printer. Some of these printers come with all their color inks in a cartridge; if you want to replace on color, you must replace all the colors. Other color ink-jet printers allow you to replace ink individually. These printers are a better choice if user uses one color more than other colors. These printers produce less noise and print in better quality with greater speed.

Advantages

1. Today you can create images or documents with high quality by Inkjet printers.

2. The inkjet printer do not require time to heat the machine system before print.
3. Inkjet printers are considerably cheaper to buy. 
4. High end printers are capable of producing good quality images when used with special paper.
5. Most models are relatively light weight and compact so they don't take up too much space on the desk. 

Disadvantages

1. Due to the cost of ink, running an inkjet printer over time is a more expensive than a laser printer.  2. Prints emerge from the printer slightly wet and may need time to dry.  3. Printing is slower and therefore inkjets aren't designed for high volume printing. 

Laser printer

A laser printer works like a photocopy machine. Laser printers produce images on paper by directing a laser beam at a mirror which bounces the beam onto a drum. The drum has a special coating on it to which toner (an ink powder) sticks. Using patterns of small dots, a laser beam conveys information from the computer to a positively charged drum to become neutralized. From all those areas of drum which become neutralized, the toner detaches. As the paper rolls by the drum, the toner is transferred to the paper printing the letters or other graphics on the paper. A hot roller bonds the toner to the paper. Laser printers use buffers that store an entire page at a time. When a whole page is loaded, it will be printed. The speed of laser printers is high and they print quietly without producing much noise. Many home-use laser printers can print eight pages per minute, but faster and print approximately 21,000 lines per minute, or 437 pages per minute if each page contains 48 lines. When high speed laser printers were introduced they were expensive. Developments in the last few years have provided relatively low-cost laser printers for use in small businesses.

Laser printing Technology

Advantage of laser printer

1. The main advantage of Laser printer is its speed & efficiency at which it prints high-quality quality graphics & text. 2. Laser printers produce high-quality output as compared to other printers. 3. Laser printers are quite and does not produce disturbing sounds.  4. They are also capable to produce color prints.

Disadvantages of Laser Printer 

1. The main disadvantage of Laser printer is its cost, they are relatively costly as compared to other printers. 2. The maintenance, repair & servicing charges are also high of these printers. 3. Laser printers emit small amount of ozone and are hazardous to health and the atmosphere.

Critical Components of the Laser Printer 

 Let’s take a look at the many components of a laser printer and their functions.
  •  The Toner Cartridge The toner cartridge in a laser printer is so named because of its most obvious activity—supplying the toner that creates the image on the page. To reduce maintenance costs, however, many other laser printer parts, especially those that suffer the most wear and tear, have been incorporated into the toner cartridge. Although this makes replacement of individual parts nearly impossible, it greatly reduces the need for replacement; those parts that are most likely to break are replaced every time you replace the toner cartridge. 
  • The Photosensitive Drum The photosensitive drum is an aluminum cylinder coated with particles of photosensitive compounds. The drum itself is grounded to the power supply, but the coating is not. When light hits these particles, whatever electrical charge they may have had “drains” out through the grounded cylinder. 
  • Erase Lamp The erase lamp exposes the entire surface of the photosensitive drum to light, making the photosensitive coating conductive. Any electrical charge present in the particles bleeds away into the grounded drum, leaving the surface particles electrically neutral. 
  • Primary Corona The primary corona wire, located close to the photosensitive drum, never touches the drum. When the primary corona is charged with an extremely high voltage, an electric field (or corona) forms, enabling voltage to pass to the drum and charge the photosensitive particles on its surface. The primary grid regulates the transfer of voltage, ensuring that the surface of the drum receives a uniform negative voltage of between ~600 and ~1000 volts. 
  • Laser The laser acts as the writing mechanism of the printer. Any particle on the drum struck by the laser becomes conductive, enabling its charge to be drained away into the grounded core of the drum. The entire surface of the drum has a uniform negative charge of between ~600 and ~1000 volts following its charging by the primary corona wire. When particles are struck by the laser, they are discharged and left with a ~100 volt negative charge. Using the laser, we can “write” an image onto the drum. Note that the laser writes a positive image to the drum. 
  • Toner The toner in a laser printer is a fine powder made up of plastic particles bonded to iron particles. The toner cylinder charges the toner with a negative charge of be-tween ~200 and ~500 volts. Because that charge falls between the original uniform negative charge of the photosensitive drum (~600 to ~1000 volts) and the charge of the particles on the drum’s surface hit by the laser (~100 volts), particles of toner are at-attracted to the areas of the photosensitive drum that have been hit by the laser (that is, areas that have a relatively positive charge with reference to the toner particles). 
  • Transfer Corona To transfer the image from the photosensitive drum to the pa-per, the paper must be given a charge that will attract the toner particles off of the drum and onto the paper. The transfer corona is a thin wire, usually protected by other thin wires that applies a positive charge to the paper, drawing the negatively charged toner particles to the paper. The paper, with its positive charge, is also attracted to the negatively charged drum. To prevent the paper from wrapping around the drum, a static charge eliminator removes the charge from the paper. In most laser printers, the transfer corona is outside the toner cartridge, especially in large commercial grade machines. The transfer corona is prone to a build-up of dirt, toner, and debris through electrostatic attraction, and it must be cleaned. It is also quite fragile usually finer than a human hair. Most printers with an exposed transfer corona will provide a special tool to clean it, but you can also very delicately use a Q-tip soaked in 90 percent denatured alcohol (don’t use rubbing alcohol because it contains emollients). As always, never service any printer without first turning it off and unplugging it from its power source. 
  • Fuser Assembly The fuser assembly is almost always separate from the toner cartridge. It is usually quite easy to locate as it will be close to the bottom of the toner cartridge and will usually have two rollers to fuse the toner. Sometimes the fuser is somewhat enclosed and difficult to recognize, because the rollers are hidden from view. To help you determine the location of the fuser, think about the data path of the paper and the fact that fusing is the final step of printing. The toner is merely resting on top of the paper after the static charge eliminator has removed the paper’s static charge. The toner must be permanently attached to the paper to make the image permanent. Two rollers, a pressure roller and a heated roller, are used to fuse the toner to the paper. The pressure roller presses against the bottom of the page while the heated roller presses down on the top of the page, melting the toner into the paper. The heated roller has a nonstick coating such as Teflon to prevent the toner from sticking to the heated roller. 
  • Power Supplies All laser printers have at least two separate power supplies. The first power supply is called the “primary power supply” or sometimes just the “power supply.” This power supply, which may actually be more than one power supply, pro-vides power to the motors that move the paper, the system electronics, the laser, and the transfer corona. The high-voltage power supply usually provides power only to the primary corona. The extremely high voltage of the high-voltage power supply makes it one of the most dangerous devices in the world of PCs! Before opening a printer to insert a new toner cartridge, it is imperative that you always turn off a laser printer! 
  • Turning Gears A laser printer has many mechanical functions. First, the paper must be picked up, printed upon, and kicked out of the printer. Next, the photo sensitive roller must be turned and the laser, or a mirror, must be moved from left to right. Finally, the toner must be evenly distributed, and the fuser assembly must squish the toner into the paper. All these functions are served by complex gear systems. In most laser printers, these gear systems are packed together in discrete units generically called gear packs or gearboxes. 
  • Ozone Filter The coronas inside laser printers generate ozone (O3). Although not harmful to humans in small amounts, even tiny concentrations of ozone will cause damage to printer components. To counter this problem, most laser printers have a special ozone filter that needs to be vacuumed or replaced periodically. 
  • Sensors and Switches Every laser printer has a large number of sensors and switches spread throughout the machine. The sensors are used to detect a broad range of conditions such as paper jams, empty paper trays, or low toner levels. Many of these sensors are really tiny switches that detect open doors and so on. Most of the time these sensors/switches work reliably. Yet occasionally, they can become dirty or broken, sending a false signal to the printer. Simple inspection is usually sufficient to determine if a problem is real or just the result of a faulty sensor/switch. 
  • Resolution Laser printers can print at different resolutions, just as monitors can display different resolutions. The maximum resolution that a laser printer can handle is determined by its physical characteristics. Laser printer resolution is expressed in dots per inch (dpi). Common resolutions are 600 × 600 dpi or 1200 × 1200 dpi. The first number, the horizontal resolution, is determined by how fine a focus can be achieved by the laser. The second number is determined by the smallest increment by which the drum can be turned. Higher resolutions produce higher quality output, but keep in mind that higher resolutions also require more memory. In some instances, complex images can be printed only at lower resolutions because of their high-memory demands. Even printing at 300 dpi, laser printers produce far better quality than dot-matrix printers because of resolution enhancement technology (RET). 
Troubleshooting Printers

As easy as printers are to set up, they are equally robust at running, assuming that you install the proper drivers and keep the printer well maintained. But printer errors do occasionally develop. Printers of all stripes share some common problems, such as print jobs that don’t go, strangely sized prints, and misalignment. Other issues include consumables, sharing multiple printers, and crashing on power-up. Let’s take a look at these general troubleshooting issues of commonly used printer like inkjet & Laser Printer.
  • Tools of the Trade
Before you jump in and start to work on a printer that’s giving you fits, you’ll need some tools. You can use the standard computer tech tools in your toolkit, plus a couple of printer-specific devices. Here are some that will come in handy: 
➣ A multi-meter for troubleshooting electrical problems such as faulty wall outlets 
➣ Various cleaning solutions, such as denatured alcohol 
➣ An extension magnet for grabbing loose screws in tight spaces and cleaning up iron-based toner 
➣ A CD-media disc or USB thumb drive with test patterns for checking print quality 
➣ Screwdriver both a Phillips-head and flat-head.

Before starts the troubleshooting steps of specific printers first have a look at common problems with solution:

Printer does not have power indicator

➣ First, make sure that the printer is on. When a printer is on it should have some light or LED(usually green) indicating it's receiving power. 
➣ If you do not have any indicator light, make sure the printer is connected to a working power outlet by verifying each end of the power cable. Next, press the printer power button. 
➣ If after doing the above steps the printer still display no power status, you have a serious printer issue and we suggest contacting the printer manufacturer for repair or replacement. Try to find out the toll free customer care no to launch the complaint over the phone for quick support 

Cables not connected properly

Your printer should have two cables connected to it: the power cable and the data cable. Make sure the power and data cables (parallel cable or USB cable) are connected to both the printer and computer. 

Printer error (orange or blinking light)

After your printer has completed its initial startup, you should see a solid colored light. If the indicator is blinking or orange often this is an indication of a printer error; like a paper jam or an issue with the ink or toner cartridge. As there are not standards for all printers, if you see a blinking light, visit the manufacturer's site for specific error details. 

No paper or paper jam

Without paper, your printer will not be able to print. Make sure you have paper in the paper loaded into the printer paper cartridge or tray. Next, verify that no printer paper is jammed or partially fed into the printer. If you suspect paper is stuck somewhere it shouldn't be, refer to our help page for paper jams.

** Now let’s discuss with the problem & solution of INKJET & LASER printer.   
                         Inkjet Printer Troubleshooting

                    Inkjet Printer Problem and Solution
Problem
Solution
The printer prints "garbage". The printer is not printing what was on screen.

      ·       This usually happens when the wrong printer driver is installed.
      ·       Check your printer's manufacturer's website for most up to date driver.
     ·    Download and install newest driver restart your computer, and the problem should be resolved.
No response from printer, computer gives error message when trying to print.
     ·       Check that the cables are properly connected to the printer and the computer.
     ·       Many PC printers require an IEEE 1284 cable or a USB cable.
    ·       Some printers for older Macintoshes require either a serial or Local Talk cable.
   ·       Consult your manual to find out what cabling you need/have.
    ·       Reconnect your cables, and check to see if the printer prints.
The printer is not printing completely across the page horizontally. Content is missing on the right half of the page.
     ·       Open the cover and make sure nothing is obstructing the movement of the print head.
     ·       Obstructions can result if you have not removed some of the packaging or if there is a paper jam.
     ·       If this is a new printer, make sure all safety tape has been removed.
The printer prints out blank pages.
    ·       There is most likely no ink cartridge installed or the ink cartridge has been exhausted.
    ·       Check your printer manual or website to figure out what ink cartridge is required. Some may require a color cartridge and a black cartridge.
    ·       Install a new ink cartridge and print a test page, it should print now.
The text printed by the printer has wrong print attributes (I.E., bold text was not printed as bold)
   ·       This usually occurs when the wrong printer drive is installed.
    ·       Check your printer's manufacturer's website for most up to date driver.
   ·       Download and install newest driver, restart your computer, and the problem should be resolved

Parts of characters are missing, or characters are not printed in correct color.


     ·       The ink cartridge is either clogged or running out of link.
     ·       Run the software cleaning utility in order to fix a clog.
     ·       Replace the ink cartridge if the clog cannot be fixed or if the cartridge is almost empty.
The printer prints faded text. 
    ·       One or more of the inkwells in the print cartridge is almost empty.
     ·       If your printer can replenish individual colors, you can add ink for the affected color.  Unfortunately if it does not, you will need to replace the whole ink cartridge.
Printout is smeared.
    ·       The paper is mismatched to the paper setting for the printer.
     ·       For example, if you are using high-quality photo paper, set the printer's output for that paper.
     ·       Press print through the file menu. Click properties, and make sure the properties for paper type, margins, etc. are correct.
Printer encounters paper jams often.
      ·       The feeder bin or tray may be overloaded, remove some of the paper.
    ·       Excess humidity may be causing the paper to stick together.
       ·       Remove all sheets and use only as much as needed.
       ·       The paper may have already been through the printer.
      ·       The feeding process tends to warp and thicken areas of the page by bunching it up.

                                                    Laser Printer Troubleshooting
                                              Laser Printer Problems and Solutions
Problem
Solution
The printed product is faded.
    ·       In most cases, you are probably running low on toner.
    ·       Take off the cover and remove the toner cartridge. (There is usually a handle to pull up and out.)
    ·        First, shake the toner cartridge, and see if you can get more life out of the "caked" toner jammed on the inside of the cartridge.
    ·       If shaking the cartridge does not yield darker printouts, you may need a toner cartridge replacement.
Printing is smeared, or there are faint lines on the page. 
     ·       The fuser may be dirty or broken.
    ·       This may require replacement.
    ·       Contact your technology coordinator in your school.
Printer is printing out blank pages
    ·       Your toner cartridge may be low.
    ·       Take off the cover and remove the toner cartridge. Shake it to see if you can get more life out of it.
    ·       Replace the cartridge and see if this fixes the problem.  
    ·       If the toner cartridge replacement does not fix the issue, the drum (what holds the toner cartridge) needs to be replaced.
Printer refuses to print a job.
    ·       Check the cables. Reconnect if necessary.
    ·         There may be a paper jam. Check the LED lights on the top of the printer and see if an error light is lit.
    ·       Some printers may point you to where the printer jam may exist. If not you may need to investigate yourself.
    ·       Remove the toner cartridge, so you will have easier access to the feeder and where the paper has probably jammed..
    ·        Gently remove the jammed paper, try to avoid ripping the paper, since this will make unjamming the printer more difficult.
    ·       Once the jam has been removed, the printer should be able to at least try to print a job again.
    ·       If not, the printer may refuse to print because the toner cartridge is exhausted. Try replacing it, and see if this fixes the issue.
    ·       Turn off the printer, and disconnect the power cord. Sometimes this will clear the flash memory, and will fix an unresponsive printer.
The printer is printing compressed or garbled print.
    ·       The print fonts on your document may be incompatible with the printer.
    ·       Try printing with a more generic font, or simplify your layout and try again.
    ·       There could possibly be a network issue. Check our network printers section, or contact your IT specialist.

                      Install & share printer in Windows

In most cases, setting up and configuring a printer in Windows is straightforward. Follow the instructions that came with your printer's software on an installation CD, or download that information from the printer manufacturer's Website. We can also configure & install printer manually by following mentioned steps. So let’s discuss the installation & configuration steps in this segment.

Step 1  

Click Start, Devices and Printers. 
Step 2  

In the window that pops up, click the Add a Printer button on the toolbar near the top.
Step 3 

In the next window, select how you will connect to your printer. If you are trying to connect your printer directly to your PC with a cord, click Add a local printer. If you are trying to connect your printer wirelessly (over a network or over Bluetooth) or you wish to connect to a printer wired to your network, click Add a network, wireless or Bluetooth printer.

                                                            For Local Printers
Step 4 
Be sure that Use an existing port is selected, and click next. 
Step 5 
Choose your printer manufacturer from the left list, followed by the model in the right list, and then click Next. You may need to click the Windows Update button to have Windows search an expanded list. Or, if you have the disk that was packaged with your printer, click have Disk... 
Step 6 
Windows will lead you through some additional steps to complete the installation.
     
                        For Network and Wireless Printers
Step 7 
Windows will attempt to locate your printer. 
Step 8 
Select your printer from the list and click Next. Follow the additional prompts to complete the installation. 
Step 9 
If your printer is not set as the default printer and you want it to be, click Start, Devices and Printers. Right-click the printer you wish to make the default, and select set as default printer from the context menu. You can also delete the printer by clicking Remove device from this context menu.
                              Printer sharing in Windows

Just because you have more than one computer doesn't mean you have to have a printer for each computer. We will now show you how to share a printer between several computers on a network in Windows 7. 
1. Click on Start in the bottom left corner of your screen. A popup list will appear. 
2. Click on Devices and Printers, from the popup list. 
3. Right click the printer you want to share. A drop-down list will appear. 
4. Select Printer properties from the drop-down list. 
5. Click on the Sharing tab 
6. Select the Share this printer check box. 

In order for other people to connect to the printer, they just have to add the network printer that you just opened for sharing to their computers. Here's how to do this. 

1. Click on Start in the bottom left corner of your screen. A popup list will appear. 
2. Click on Devices and Printers from the popup list. 
3. Select Add a printer. 
4. Click on Add a network, wireless or Bluetooth printer.  
5. Click the shared printer. 
6. Click Next. [Source: Microsoft]

Scanner

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for

scanning black-and-white only, or color. Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display. Scanning technology has advanced to the point where you can scan documents with almost perfect clarity and capture a quick scan with a device that fits in your pocket. As with many technologies, choosing the right type of scanner for your needs depends on the type of work you want to do with it.

Standard Scanners

Standard scanners come in two basic configurations. Flatbed scanners are available as standalone units, or come integrated with other print hardware such as a printer, photocopier and fax machine. On a flatbed scanner, you place the paper on a screen and then scan it. The other standard scanner type is a feed-through scanner. It works like a fax machine or a printer you feed a page through the unit. These units are typically smaller than flatbed scanners, and some are specifically designed to be portable.

Specialized Scanners 

There are several types of specialty scanners. For instance, small business card scanners allow you to quickly scan in the cards you receive while networking. Other units are designed for scanning high-quality photos. Drum scanners are a completely different type of scanner that spins the image at high speed while it is scanned pixel by pixel, creating the highest possible quality scanned image. These scanners are often used in commercial.

Flatbed scanner:

Flatbed scanners will take up some desktop space but provide a lot of bang for the buck. They look like miniature printers with a flip-up cover protecting the glass platen. Depending on its size, a flatbed scanner can fit standard or legal-sized documents, and the flexible cover allows you to scan large items such as books. These scanners are great for scanning the occasional newspaper article, book chapter, or photograph; or for those who may need to scan or bulky items such as the cover of a DVD.

Sheet-fed scanners

Sheet-fed scanners are smaller than flatbed scanners; as the name implies, you feed a document or photo into the scanner rather than place it on top. You’ll win back some of that desktop space with a sheet-fed scanner but you may sacrifice some resolution in the process. If you’re only scanning documents, however, it may be a worthwhile trade, especially if you’ve got a lot of them since you can feed them in bunches. With a flatbed scanner, you’ll have to scan one page at a time.
                                             
Handheld Scanner

Hand scanners are useful for their portability and low price (often one-third to a quarter of the cost of a flatbed scanner). Hand scanners generally plug into a computer's printing port, as opposed to a SCSI port, allowing them to be easily shared from workstation to workstation. Many people find them ideal for use with a notebook or laptop. Unfortunately, hand scanners are less accurate than flatbeds because they have weaker light sources and often produce uneven scans - courtesy of the unsteadiness of your hand or the surface you're standing on. Many hand scanners now offer an alignment template to help guide you when scanning.  

Drum Scanners

Professional color trade shops wouldn't think of using anything less than a drum scanner for producing color separations for high-end printing. Instead of using CCD technology, drum scanners use PMT (Photo Multiplier Tube) technology for greater dynamic range and color accuracy. 

                                      Scanning Process

Here are the steps that a scanner goes through when it scans a document: 

  • The document is placed on the glass plate and the cover is closed. The inside of the cover  in most scanners is flat white, although a few are black. The cover provides a uniform background that the scanner software can use as a reference point for determining the size of the document being scanned. Most flatbed scanners allow the cover to be removed for scanning a bulky object, such as a page in a thick book. 
  • A lamp is used to illuminate the document. The lamp in newer scanners is either a cold cathode fluorescent lamp (CCFL) or a xenon lamp, while older scanners may have a standard fluorescent lamp. 
  • The entire mechanism (mirrors, lens, filter and CCD array) make up the scan head. The scan head is moved slowly across the document by a belt that is attached to a stepper motor. The scan head is attached to a stabilizer bar to ensure that there is no wobble or deviation in the pass. Pass means that the scan head has completed a single complete scan of the document.  
  • The image of the document is reflected by an angled mirror to another mirror. In some scanners, there are only two mirrors while others use a three mirror approach. Each mirror is slightly curved to focus the image it reflects onto a smaller surface. 
  • The last mirror reflects the image onto a lens. The lens focuses the image through a filter on the CCD array.

The filter and lens arrangement vary based on the scanner. Some scanners use a three pass scanning method. Each pass uses a different color filter (red, green or blue) between the lens and CCD array. After the three passes are completed, the scanner software assembles the three filtered images into a single full-color image. Most scanners today use the single pass method. The lens splits the image into three smaller versions of the original. Each smaller version passes through a color filter (either red, green or blue) onto a discrete section of the CCD array. The scanner combines the data from the three parts of the CCD array into a single full-color image.

Another imaging array technology that has become popular in inexpensive flatbed scanners is contact image sensor (CIS). CIS replaces the CCD array, mirrors, filters, lamp and lens with rows of red, green and blue light emitting diodes (LEDs). The image sensor mechanism, consisting of 300 to 600 sensors spanning the width of the scan area, is placed very close to the glass plate that the document rests upon. When the image is scanned, the LEDs combine to provide white light. The illuminated image is then captured by the row of sensors. CIS scanners are cheaper, lighter and thinner, but do not provide the same level of quality and resolution found in most CCD scanners.

Before you can scan documents into your computer with a scanner, you need to install the scanner driver so that your scanner and computer can communicate. Start by connecting the scanner to your computer’s USB port (see your scanner manual for information about how it connects to your computer). Some scanners use Plug and Play, a technology that Windows uses to recognize equipment and automatically install and set it up. If your scanner is Plug and Play-enabled, Windows 7 shows a Found New Hardware message in the Task-bar notification area (in the lower-right corner). Most Plug and Play devices will then automatically install, the message will change to verify the installation is complete, and that’s all you have to do.

Steps to install a scanner

1. Turn the scanner on. If you’re not using a Plug and Play device or Windows doesn’t have the driver for that device, you see the Found New Hardware message. 
2. Click the Found New Hardware message, click Yes, This Time Only, and then click next again. You only need to do this step if you don’t permit Windows 7 to automatically connect to Windows Update. Otherwise, you don’t see the Found New Hardware Wizard. 
3. If you have a CD for the scanner, insert it in your CD drive and click next. Windows 7 searches for your scanner driver software and installs it. 
4. Choose Start→ Control Panel and type scanners in the Search box. Windows returns a set of links. 5. Click the View Scanners and Cameras link. The Scanners and Cameras window appears. 
6. Click the Add Device button and then click next. The Scanner and Camera Installation Wizard window appears. When you click next, the next screen of the wizard appears.
7. Click a Manufacturer in the list on the left and then click a model in the list on the right. Now it’s just a matter of following the wizard directions based on the model of scanner you choose and whether you have a manufacturer’s disc (a CD- or DVD-ROM). If you don’t have a disc, Windows can help you download software from the Internet. 
8. When you reach the end of the wizard, click Finish. The installation is complete. 

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