b. Problems associated with laser printers and probable causes:
1. Speckled pages: The causes for this may be
a. The failure to clean the drum after printing properly, or
b. The drum might have developed scratches.
2. Blank pages: The causes for white pages may be
a. . The toner would have dried out, replace the toner.
b. The transfer corona, that is responsible for transferring the toner to the drum might have failed.
c. The High Voltage Power Supply (HVPS) failure will also result in white pages.
3. Ghosted Images: Ghosting occurs when previously printed pages are printed again, though much lighter than the present image. The most likely cause is that the erasure lamp might not be working properly, thus leaving some charges representing the earlier image left on the photosensitive drum before new image is written. Also check the cleaning blade, which is responsible for scraping the residual toner.
4. Smudged images: If the fusing fails, the toner will not bond with the paper. Check the halogen lamp responsible for heating.
c. Typically, a laser printer maintenance kit consists of fuser fixing assembly, pickup rollers, transfer roller, gloves, and instruction manual.
2. Impact printers
a. Impact printers are capable of printing multipart forms, since they can give necessary impact to print to multiple forms simultaneously.
b. ECP (Extended Capability Port) has less control overhead and best suited for transferring large chunks of data, such as between the computer and laser printer.
3. InkJet Printers
InkJet Printers is the generic name given for contact less printing using ink. Friction feed is most commonly used with laser printers, and Inkjet printers. One needs to check the calibration for the inkject printer if it is not printing properly. If it doesn't help, then check the ink cartridge if it requires replacement.
4. Thermal printers
Thermal printers require a special kind of paper, called thermal paper. This paper is sensitive to heat, and the printing is produced by thermal heat applied on the paper by the print head.
1. Printer parallel ports come in the following varieties
a. Unidirectional: Here, the data travels only from the computer to the peripheral (printer) device.
b. Bi-directional: Here, the data travels both from the computer to the peripheral device and vice-verse.
c. ECP (Extended Capability Port): ECP mode offers bi-directional data transfer, as well as DMA for data transfer.
d. EPP (Enhanced Parallel Port): In addition to bi-directional features, it offers an extended control code set
e. The port that a printer is using can be found by going to Control Panel -> Printers and right click on appropriate printer. Choose Ports tab to view the port (like COM1, COM2, USB001, etc.) that the printer is using.
2. Cable lengths
a. Serial cable maximum length is 50 feet.
b. Parallel cable maximum length is 10 feet.
c. Longer cable lengths may lead to some errors & garbage characters.
3. RJ – cables
a. RJ-11: These connectors are used to link modem / phone to the phone line. They have only two pins that get into the modem.
b. RJ-14: RJ-14 connectors are dual-line phone jacks that can accommodate up to 2 telephone line.
c. RJ-45: RJ-45 cable is widely used for attaching UTP cable in LAN environment. These connectors have eight pins.
d. The widely used interface cables have the following pin count:
SCSI Ultra wide-68 pin
4. Ultra IDE cable has 80 wires, and handles better speeds compared to IDE cable with 40 wires. The additional wires are introduced to reduce noise and thereby improving speed
5. Thin co-axial and thick co-axial cables have conductive grounding sheath surrounding the center conductor. Therefore, the electromagnetic interference (EMI) is significantly less.
6. Cat 6 cabling is recommended for Gigabit Ethernet networking.
7. Centronics cable, used for parallel printing will have a male DB-25 connector at one end and a female 36 pin connector at the other end.
8. The default spool folder is located at: Systemroot\System32\spool\printers. For example, if the OS is residing on C drive, the default location will be: “C:\\Windows\System32\spool\printers”.You can access this location through:
Start -> Printers -> File -> Server Properties -> Advanced tab. Type in the new spool location over the default location.
9. While connecting a printer using USB if Operating System is not recognizing the USB port you need to make sure that the USB interface is enabled in the BIOS. Note that Windows 95, Windows NT4.0 (Upto service pack 4) do not support USB. Also, make sure that the motherboard BIOS supports USB.
10. A network printer can be added to Windows XP computer by going to Control Panel (classic view), Printers and Faxes applet, This will initiate Add Printer wizard. In Category View, choose Printers and Other Hardware hyperlink and select Add Printer option.
11. When a printer is installed on a network, default printer permissions are assigned that allow all users to print. Because the printer is available to all users on the network, you might want to limit access for some users by assigning specific printer permissions. For example, you could give all non-executive users in a department the Print permission and give all managers the Print and Manage Documents permissions. You can also deny print permission to all others. In this way, all non-executive users and managers can print documents, but managers can also change the print status of any document sent to the printer.
12. If you share a printer with users running other versions of Windows (Windows 98, XP, Vista, etc), you can install additional printer drivers on your computer so those users can connect to your printer without being prompted to install the drivers missing from their systems.
13. Scanner installation process is much like a print device. Because so many of these now are USB, plugging them in will install the driver. In cases where that does not work (usually when it is a very new model and the operating system is older), use the installation disc to install the driver.
Monitors, speakers, and projectors normally do not require a driver to perform.
14. A scanner driver is usually called TWAIN. The Twain driver will always have another name, for example, Microtek calls theirs ScanWizard, and HP calls it as DeskScan or PrecisionScan. The TWAIN driver comes with the scanner, and knows how to operate this one brand of scanner hardware. Each scanner manufacturer provides their own TWAIN driver for their hardware.
15. Windows XP provides three levels of printing security permissions: Print, Manage Printers, and Manage Documents. When multiple permissions are assigned to a group of users, the least restrictive permissions apply. However, when Deny is applied, it takes precedence over any other permission.
a. Print: The user can connect and print document. By default, the Print permission is assigned to all members of the Everyone group.
b. Manage Printers: The user has complete administrative control of the printer. The user can pause and restart the printer, change spooler settings, share a printer, change printer permissions, and change printer properties. By default, the Manage Printers permission is assigned to members of the Administrators and Power Users groups.
c. Manage Documents: The user can pause, resume, restart, cancel, and rearrange the order of documents submitted by all other users. The user cannot, however, send documents to the printer or control the status of the printer. By default, the Manage Documents permission is assigned to members of the Creator Owner group.
16. In Windows 7 Operating System, most printers and other peripheral devices are automatically detected and drivers are installed. Therefore, first you must see if the OS itself recognizes the device and installs the drivers. If you are prompted to locate the driver, the browse to the driver location and direct the installation.