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Difficulty: MediumPrinter and Multifunction Device Issues

An IT support technician is troubleshooting a monochrome laser printer in an accounting firm. Users report that printed pages show a faint repeating duplicate image (ghosting) of previously printed text appearing down the page at regular intervals of approximately 3.75 inches3.75\text{ inches} (95 mm95\text{ mm}). The toner on the pages is fully adhered and does not smudge when touched. Which of the following components is the most likely cause of this print quality defect?

  1. A worn cleaning blade failing to scrape residual toner off the photosensitive drumAnswer
  2. B
    A degraded fuser heating element failing to reach optimal fusing temperature
  3. C
    A faulty primary corona wire failing to condition the drum surface with a uniform charge
  4. D
    A misaligned transfer roller providing insufficient voltage to attract toner to the paper

Answer

A worn cleaning blade failing to scrape residual toner off the photosensitive drum is the root cause of the repeating ghosting defect.
In the electrophotographic (EP) printing process, the cleaning phase uses a rubber wiper blade to scrape remaining toner off the photosensitive drum after image transfer. If the blade is worn or damaged, residual toner remains on the drum surface and creates repeating faint ghost images at intervals matching the circumference of the drum.

Step-by-Step Solution

1
Analyze the reported defect symptoms and repeat pattern.
The defect is a repeating ghost image at a specific fixed distance (3.75 inches3.75\text{ inches}). The toner is fully fused, eliminating fuser temperature failure.
Repeating defects at regular intervals correspond to the circumference of a rotating roller inside the laser printing assembly.
2
Correlate the interval measurement (3.75 inches3.75\text{ inches}) with electrophotographic drum dimensions.
A distance of 3.75 inches3.75\text{ inches} corresponds to a drum diameter d=3.75π≈1.2 inchesd = \frac{3.75}{\pi} \approx 1.2\text{ inches}, matching a standard photosensitive drum circumference.
If leftover toner from a previous image is not cleared during the cleaning phase of the EP process, it transfers again on the next rotation of the drum.
3
Identify the failing component responsible for clearing residual toner during the cleaning step.
The rubber cleaning blade (wiper blade) failed to scrape leftover toner into the waste toner cavity.
Replacing the drum unit or toner cartridge containing the damaged cleaning blade resolves the ghosting issue.

Key Concept

Electrophotographic Printing Process - Cleaning Phase Defects
Estimated Time:1m 15s
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Topics

Printer and Multifunction Device Issues

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