Scan quality depends heavily on a clean, unobstructed path between the document and the internal sensor, and even a small amount of dust or residue on the scanning glass can noticeably affect every scan produced afterward.
Why This Gets Overlooked
Scan glass/sensor cleaning is easy to overlook because the resulting quality decline happens gradually rather than all at once — a faint line or slight discoloration on scans often goes unnoticed for weeks before someone compares a recent scan to an older one and realizes something has changed. Dust, fingerprints, and toner residue from nearby equipment are the most common contaminants affecting scan glass over time.
Identifying Glass and Sensor Contamination
Persistent lines or streaks appearing in the exact same position on every scan, regardless of the source document, are the clearest sign of a dirty scan glass or sensor rather than a document quality issue. This consistency is the key diagnostic clue — a mark that moves or changes between scans points elsewhere, while one that stays fixed points directly to the glass or sensor.
Proper Cleaning Technique
Cleaning scan glass requires care, since standard household glass cleaners can sometimes leave residue or streaking that's worse than the original problem. A proper scan glass/sensor cleaning uses appropriate lint-free materials and cleaning solutions designed specifically for optical equipment, avoiding both scratches and chemical residue that could interfere with future scans.
Automatic Document Feeder Glass
Scanners with automatic document feeders have a second, narrower strip of glass that documents pass over during feeding, separate from the main flatbed glass. This strip is particularly prone to dust and debris buildup given how frequently paper passes directly over it, and it's often the source of a persistent line specifically on feeder-scanned documents while flatbed scans remain clean.
Estimated Cost of Cleaning Services
| Service | Approximate Cost (KES) |
| Standard scan glass cleaning | 800 – 1,500 |
| Sensor and internal component cleaning | 1,200 – 2,500 |
| Document feeder glass strip cleaning | 1,000 – 2,000 |
| Full diagnostic and cleaning service | 1,500 – 3,000 |
Book a Service
Persistent lines on scans usually mean it's time for a proper scan glass/sensor cleaning. Bestcare Facilities Management restores scan clarity for offices across Nairobi.