220-1101 Hardware and Network Troubleshooting Practice Question
A technician is troubleshooting a laser printer that produces pages with a horizontal black line across the top of every page. The line is the same width as the page and appears in the same location each time. The technician has already replaced the toner cartridge and the imaging drum. Which of the following printer components should the technician check NEXT?
⚠ Common exam trap
Watch out — candidates often confuse the fuser with the imaging drum or transfer roller, assuming any horizontal line must be caused by the drum, but the drum defect would produce a line that repeats at the drum's circumference (typically a different distance from the top) and would have been resolved by replacing the drum.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Fuser
The fuser assembly uses heat and pressure to permanently bond toner to the paper. A damaged fuser roller (e.g., a nick, scratch, or melted toner buildup) will imprint a consistent horizontal line across the top of every page because the defect contacts the paper at the same rotational point each time. Replacing the toner cartridge and imaging drum did not resolve the issue, confirming the problem is downstream in the fuser.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Transfer roller
Why it's wrong here
The transfer roller applies a charge to the paper to pull toner off the drum and onto the sheet during the transfer step. If the transfer roller is damaged or contaminated, it will cause localized transfer failures that appear as light spots, faded bands, or sometimes vertical streaks, depending on the roller's surface. It does not produce a solid horizontal line, because the roller's contact area and charge distribution are consistent across the paper width; a defect would show as uneven density, not a single clean line.
When this WOULD be correct
A technician troubleshooting a laser printer that produces pages with vertical streaks or light areas would check the transfer roller. If the transfer roller is worn or dirty, it fails to properly transfer toner, leading to such defects.
- ✓
Fuser
Why this is correct
The fuser assembly bonds toner to the paper using a combination of heat and pressure from heated rollers. If the fuser roller becomes scratched, gouged, or has melted toner stuck to its surface, it will imprint a fixed horizontal line or band onto every sheet that passes through. Because the defect is tied to the roller's circumference, the line appears in the same position relative to the leading edge each time, making this the classic cause of a repeating horizontal line across all pages.
- ✗
Primary corona wire (or charge roller)
Why it's wrong here
The primary corona wire (or charge roller) applies a uniform electrostatic charge to the photoconductor drum during the charging step. A dirty or damaged corona wire causes an uneven charge, which leads to toner being developed in distinct patterns—typically vertical streaks or dark bands that run down the page. A horizontal line is not characteristic of a corona defect because the wire runs the full length of the drum, so any charge irregularity repeats along the page's height rather than as a single horizontal mark.
When this WOULD be correct
The primary corona wire (or charge roller) would be the correct next step if the symptom were vertical black streaks or repeating marks down the page, or if the page had a uniform gray background (toner dusting) due to improper charging.
- ✗
Pickup rollers
Why it's wrong here
Pickup rollers are mechanical components that engage the paper tray to feed sheets into the printer. They can cause jams, misfeeds, or multi-sheet feeds when worn or contaminated, but they never come into contact with the drum, toner, or the printed image. Since print defect lines are created by components that affect toner transfer or fusing, pickup rollers cannot produce a horizontal line on the page.
When this WOULD be correct
When pages are not feeding, multiple pages feed at once, or paper jams occur frequently, the pickup rollers should be checked or replaced.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓FuserCorrect answer▾
Why this is correct
The fuser assembly bonds toner to the paper using a combination of heat and pressure from heated rollers. If the fuser roller becomes scratched, gouged, or has melted toner stuck to its surface, it will imprint a fixed horizontal line or band onto every sheet that passes through. Because the defect is tied to the roller's circumference, the line appears in the same position relative to the leading edge each time, making this the classic cause of a repeating horizontal line across all pages.
✗Transfer rollerWrong answer — click to see why▾
Why this is wrong here
A horizontal black line across the top of every page indicates a fuser issue, not a transfer roller problem. The transfer roller typically causes image quality issues like ghosting or poor transfer, not a consistent line at the top.
★ When this WOULD be the correct answer
A technician troubleshooting a laser printer that produces pages with vertical streaks or light areas would check the transfer roller. If the transfer roller is worn or dirty, it fails to properly transfer toner, leading to such defects.
Why candidates choose this
Candidates may confuse the transfer roller's role in toner transfer with the fuser's role in fixing toner, or they might think a horizontal line could be caused by a roller issue without considering the specific location and consistency of the defect.
✗Primary corona wire (or charge roller)Wrong answer — click to see why▾
Why this is wrong here
A horizontal black line across the top of every page is typically caused by a damaged fuser roller, not the primary corona wire. The primary corona wire causes vertical streaks or faint images, not a solid horizontal line.
★ When this WOULD be the correct answer
The primary corona wire (or charge roller) would be the correct next step if the symptom were vertical black streaks or repeating marks down the page, or if the page had a uniform gray background (toner dusting) due to improper charging.
Why candidates choose this
Candidates may confuse the primary corona wire's role in charging with the fuser's role in fixing toner, or they may think any line defect is related to the charging system.
✗Pickup rollersWrong answer — click to see why▾
Why this is wrong here
Pickup rollers are responsible for feeding paper from the tray, not for image formation. A horizontal black line across the top of every page is a fuser issue, not a paper feed problem.
★ When this WOULD be the correct answer
When pages are not feeding, multiple pages feed at once, or paper jams occur frequently, the pickup rollers should be checked or replaced.
Why candidates choose this
Candidates may confuse paper path components with image formation components, or assume that any repetitive defect is caused by rollers.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.