Printers and Scanners: More on the printing process

Which component of a laser printer is responsible for attaching the toner to the paper and making the print job permanent?
1. >>Fuser assembly
2. Photosensitive drum
3. Transfer corona
4. Print head

Explanation : The fuser assembly is the part of the laser printer that performs the final step in creating a printed page. Prior to this point, the toner is attracted to the page because of a difference in electrical charges. However, the toner is not permanently attached. The fuser assembly heats the toner and the paper, melting the plastic in the toner. The roller in the fuser assembly then presses the toner onto the page, making the print job permanent (fusing the image to the paper).

The transfer corona (or transfer roller) is used to apply a positive charge to the paper so that the paper attracts the negatively charged toner.

The photosensitive drum is used to create the image that will be printed. It is first given a strong uniform negative charge (between -800 and -1200V). Next, the image is "written" to the drum using the laser beam, which changes the charge of the dots that should be written to a low negative charge (between -200 and -400V). The toner, which is given a higher negative charge than the dots (around -600V) are attracted to the areas where the dots are drawn, thus forming the image on the drum.
A print head is used on impact printers, such as dot-matrix printers and on inkjet printers. A laser printer does not have a print head.
Objective: Printers and Scanners

Printers and Scanners: Continuous Black Line on Page

A laser printer prints a continuous black vertical line down the center of each page.
What is the most likely problem?
1. >>The fusing roller is dirty.
2. The toner cartridge is empty.
3. The corona wire is broken.
4. The drum is scratched.
Explanation : When a continuous black line appears on every page, it usually indicates that the photosensitive drum has been scratched. You should replace the drum or the toner cartridge if the drum is part of the toner cartridge.
If the fusing roller were dirty, the problem would most likely be a series of repeated marks instead of a continuous line.

If the toner cartridge were empty, the problem would be uneven, light, or no print on the page.

If the corona wire were broken, the problem would most likely be a blank page.
Objective: Printers and Scanners

Printers and Scanners: White Vertical Lines on Paper

You are diagnosing a problem with a laser printer. When the laser printer prints, each page has white vertical lines running down it.
What should you try first?
1. >>Shake the toner cartridge.
2. Reinstall the printer driver.
3. Clean the photosensitive drum.
4. Replace the fuser assembly.

Explanation : When a laser printer prints pages with vertical white lines, it usually means that the toner cartridge is clogged so toner is not being distributed evenly. The first thing to try is to shake the toner cartridge to try to remove the clog. If that does not work, replace the toner cartridge.

The problem is probably not caused by a dirty photosensitive drum. A dirty or scratched photosensitive drum can cause a mark on the paper that repeats at regular intervals. A dirty drum will not normally cause white vertical lines.

You should not replace the fuser assembly. A problem with the fuser assembly would generally result in smudges or blotches on the page. It is not the first thing to check when diagnosing white lines on the page.

The problem is most likely not related to the printer driver. The printer driver is responsible for translating application and operating system commands to a language the printer can understand. Vertical white lines are caused by an ink distribution problem, not a translation problem.
Objective: Printers and Scanners