220-1201 Practice Question: That their laser printer is producing pages with…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Toner cartridge is low on toner.

  Why it's wrong here

  When a toner cartridge is low on toner, the printer typically produces output that appears faded, light, or patchy across the entire page, often with areas of missing print. This occurs because there isn't enough toner powder available to uniformly cover the electrostatic image on the drum. It does not, however, cause distinct, repeating black streaks, which are indicative of a localized physical defect on a specific imaging component.

• ✓

  Drum unit is scratched or damaged.

  Why this is correct

  A scratched or damaged drum unit is the most common cause of repeating black streaks or lines on laser printer output. The photosensitive drum is responsible for attracting and transferring toner to the paper; a physical scratch on its delicate surface disrupts the electrostatic charge in that specific area. This defect causes the scratched portion to either pick up excess toner or fail to properly release it, consistently transferring the flaw as a repeating mark on every page as the drum rotates.

• ✗

  Fuser assembly is malfunctioning.

  Why it's wrong here

  A malfunctioning fuser assembly primarily affects the final bonding of toner to the paper, rather than causing distinct black streaks. If the fuser, which uses heat and pressure, is not operating correctly, toner will not be properly melted and pressed into the paper fibers. This typically results in print that smudges easily, flakes off, or appears poorly adhered to the page, but it does not create the sharp, repeating vertical lines characteristic of a drum defect.

• ✗

  Pickup rollers are worn out.

  Why it's wrong here

  Worn-out pickup rollers are responsible for feeding paper from the tray into the printer's paper path, and their malfunction leads to paper handling issues, not print quality defects. When these rollers lose their grip, they cause symptoms such as paper jams, misfeeds (where no paper is picked up), or multifeeding (where multiple sheets are fed at once). They have no direct involvement in the image formation or toner transfer process, and therefore cannot cause black streaks on the printed output.

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