CompTIA®A+ Exam Notes : Troubleshoot Printers With Appropriate Tools

4. Hardware and Network Troubleshooting

4.5 Troubleshoot printers with appropriate tools

Problems associated with laser printers and probable causes:

1. Speckled pages: The causes for this may be

  • The failure to clean the drum after printing properly, or
  • The drum might have developed scratches.

2. Blank pages: The causes for white pages may be

  • The toner would have dried out, replace the toner.
  • The transfer corona, that is responsible for transferring the toner to the drum might have failed.
  • 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.

  • The toner is negatively charged, so that it gets attracted towards the positively charged paper surface (due to positively charged transfer corona).
  • The manufacturer specifies the field replaceable parts, and usually, the print heads and toner catridges are the only FRUs (Field Replaceable Parts).
  • Nickel Cadmium battery is not environmentally friendly and not as efficient as Nickel/Metalhydride or Lithium Ion. Nickel/Metal hydride, though environmentally friendly, not as efficient as Lithium Ion. Lithium Ion battery is environmentally friendly and very efficient.
  • Typically, a laser printer maintenance kit consists of fuser fixing assembly, pickup rollers, transfer roller, gloves, and instruction manual.

The following are the 6 steps in the ElectroPhotographic (EP) print process of Laser Printer:

1. Cleaning: Cleaning the photosensitive drum includes residual toner left on the drum and removing the electrical charges left out on the drum. The physical cleaning is done with a rubber blade and the electrical charge cleaning is done with erasure lamps.

2. Charging: The next step in printing, is to charge the photo sensitive drum with high negative charge, this is done with the help of a corona wire.

3. Writing: A laser (type 3) sweeps the entire length of the drum, creating the static image of the matter to be printed. The places where the laser travel, the highly charges are neutralized. Other places of the drum, it remains highly negatively charged

4. Developing: Now drum gets in close proximity to the toner. Because the toner is negatively charged, it gets attracted to the areas where the drum is neutral. It will not be attracted to the places where the drum is highly negatively charged. Thus the image of the page to be printed formed on the photosensitive drum

5. Transferring: Now, the toner on the drum gets attracted toward the paper, by using highly positive charges developed on the surface of the paper. The "transfer corona" is used to generate highly positive charge on the paper surface and to attract the toner from the drum. Thus the image of the page to be printed formed on the paper. But still, the toner is loose and can get easily smeared.

6. Fusing: In order to permanently bond the toner particles to the paper, the paper is passed through rollers. One of the rollers, the non stick roller is heated by a high intensity lamp, generating the heat necessary to bond the toner to the surface of the paper.

Lightning Connector: The Lightning connector is proprietary to Apple, and is solely used on Apple devices, such as iPhones and iPads It is able to output a larger amount of power than traditional chargers for faster charging, and it does not have to be turned a specific way to connect it to the charge port on your phone. The following are some of the advantages of lightning connector

  • It can supply more power

  • It can be inserted either way

  • It is physically more durable than USB

  • It can detect and adapt to connected devices.

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