Question 1
A technician is troubleshooting an all-in-one laser printer that prints a vertical line when making copies and scans. When users print or receive faxes, the output from the printer is correct. Which of the following should the technician examine to determine the cause of the issue?
I agree with the suggested answer C (The document feeder). The problem is isolated to processes involving the scanner assembly (copying and scanning), while internal print jobs (printing and receiving faxes) are unaffected. This clearly points to a physical issue on the Automatic Document Feeder (ADF) scanning glass rather than the laser printing engine.
Reason
Option C is correct because a vertical line that only appears during scans or copies usually indicates a speck of dust, dirt, or a scratch on the small strip of scanner glass used by the ADF. As the paper moves over the stationary debris, it creates a continuous vertical line on the resulting digital image or print. Since regular prints are clear, the imaging drum and fuser are proven to be functional.
Why the other options are not as suitable
- Option A is incorrect because pickup rollers are responsible for grabbing paper from the tray; if they were faulty, you would experience paper jams or failed feeds, not image artifacts like vertical lines.
- Option B is incorrect because a dirty or damaged corona wire would cause issues on every single page the printer produces, including faxes and internal prints, which the scenario explicitly states are correct.
- Option D is incorrect because the drum assembly is part of the EP (Electrophotographic) process used for all output; if the drum were scratched or dirty, the vertical line would appear on prints and faxes as well as copies.