A desktop technician is assigned a support ticket for a high-volume departmental laser pri… — CompTIA A+ (Core 1 & Core 2)

A desktop technician is assigned a support ticket for a high-volume departmental laser printer that produces printed documents with small, repeating black smudges appearing at consistent intervals down the vertical length of every page. The technician measures the distance between the center of two consecutive smudges and records it as exactly $37.7\text{ mm}$ . According to the printer manufacturer's technical reference guide, the circumferences of internal rollers are as follows:

Component Roller	Circumference
Primary Charge Roller	$37.7\text{ mm}$
Transfer Roller	$50.2\text{ mm}$
Fuser Roller	$75.4\text{ mm}$
Photosensitive Drum	$94.2\text{ mm}$

Based on these diagnostic findings, which internal printer component is the root cause of the repeating print defect?

Primary Charge RollerAnswer
B
Photosensitive Drum
C
Fuser Roller
D
Transfer Roller

Answer

Primary Charge Roller

In electrophotographic (laser) printer diagnostics, repeating defects down a printed page occur when a specific roller has surface damage, toner build-up, or a physical pit. The distance between consecutive occurrences of the defect equals the exact circumference of the failing cylindrical component (

C = \pi \times d

). Because the measured distance between smudges is

37.7\text{ mm}

, matching the Primary Charge Roller's circumference of

37.7\text{ mm}

, the Primary Charge Roller is the root cause.

Step-by-Step Solution

Identify the pattern of the print defect.

The defect is a repeating mark at a fixed linear interval of

37.7\text{ mm}

along the paper path.

Repeating defects in electrophotographic (laser) printers are caused by surface damage, pitted areas, or debris on a rotating cylindrical component.

Apply the geometric relationship between defect interval and roller circumference.

The linear distance between repeating marks equals the circumference (

C

) of the defective roller (

D = C = 37.7\text{ mm}

Each full revolution of a damaged roller transfers the defect onto the paper at an interval equal to its circumference.

Compare the measured interval against component specifications.

The

37.7\text{ mm}

interval uniquely matches the Primary Charge Roller.

Matching empirical measurement to manufacturer roller specs determines the precise component needing cleaning or replacement.

Key Concept

Repetitive Defect Ruler Analysis in Electrophotographic Printing

Estimated Time:2m 0s

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