Black or White Dots on Prints
Overview
If your prints have small black or white dots appearing at regular intervals, this is usually caused by a damaged or dirty component inside the printer. This article helps you identify which component is responsible based on the spacing between the dots, and walks you through fixing it.
Symptoms
- Small black dots, spots, or specks repeating down the page
- Small white dots or voids appearing in printed areas
- The dots appear at consistent, regular intervals (not random)
- The issue may affect one colour or all colours
Diagnose the Problem: Measure the Spacing
The key to identifying the faulty component is measuring the distance between repeating marks. Print a test page with a solid colour area, then measure the gap between two identical dots or marks using a ruler.
| Spacing Between Marks | Likely Component | What to Do |
|---|---|---|
| ~30 mm (1.2 in) | Image drum — internal foreign object | Open and close the front cover. Print again. If the problem persists, replace the drum. |
| ~85 mm (3.3 in) | Fuser unit — surface damage or buildup | Replace the fuser unit. |
| ~94 mm (3.7 in) | Image drum — surface damage or dirt on the green tube | Gently wipe the green drum surface with a soft, dry tissue. Replace the drum if marks remain. |
| Identical voids repeating | Transfer belt — scratches or dents | Inspect the belt surface for visible damage. Replace the transfer belt if marked. |
Tip: If you are unsure which colour drum is causing the problem, print a separate test page in cyan, magenta, yellow, and black. The dots will only appear in the colour linked to the damaged drum.
Solution
Step 1: Run a Drum Cleaning Page
Run a Drum Cleaning Page first. This clears toner residue from the drum surface and resolves most minor dot issues without replacing any parts.
See: How to Generate a Drum Cleaning Page
Step 2: Clean the LED Head
Dust or toner particles on the LED head can cause white dots or faded spots. Open the front cover and gently wipe each LED head with a soft, dry, lint-free cloth.
Location of LED heads: The LED heads sit directly above each image drum inside the printer. When you open the front cover and pull out the drum/toner assembly, the LED heads are visible as narrow glass strips across the top of each drum slot.
Step 3: Clean or Replace the Image Drum
If the dots repeat at ~30 mm or ~94 mm intervals:
- Open the front cover and remove the drum/toner unit for the affected colour.
- Look at the green surface of the image drum. Do not touch it with your fingers.
- If you see toner spots or dust, gently wipe the green surface with a soft, dry tissue. Wipe in one direction only — do not rub back and forth.
- Reinstall the drum and print a test page.
- If the marks are still there, the drum surface is damaged, and the drum needs replacing.
Important: Do not expose the image drum to direct sunlight or strong light (above 1,500 lux) for more than 5 minutes. Work in normal indoor lighting and reinstall promptly.
Step 4: Check the Transfer Belt
If the dots appear across all colours in the same position, the transfer belt is likely damaged:
- Open the front cover.
- Remove the transfer belt assembly.
- Hold the belt at an angle to inspect the surface. Look for scratches, dents, or toner buildup.
- If the belt surface is damaged, it needs replacing.
Common cause: Paper jams can damage the transfer belt surface. If dots appeared after a recent paper jam, the belt is the most likely cause.
See: Replacing the Transfer Belt
Step 5: Replace the Fuser Unit
If marks repeat at ~85 mm intervals, the fuser unit roller has surface damage:
- The fuser cannot be cleaned — it must be replaced.
- Follow the fuser replacement instructions for your model.
Prevention
- Handle paper carefully when clearing jams — pulling paper out roughly can scratch the transfer belt and fuser rollers.
- Store paper in a dry location. Damp paper can leave residue on the drum surface.
- Use genuine OKI consumables. Third-party toner cartridges may shed excess toner that contaminates the drum and belt.
- Run a Drum Cleaning Page after replacing any consumables (drum, toner, belt) to clear residual toner from the system.
Applies To
All OKI printers supplied by Mediaset: C650, C844, MC853, MC873, MC883, ES8453, ES8473, ES8483, Pro9431.
Related Articles
- How to Generate a Drum Cleaning Page — Quick cleaning step that resolves most minor dot issues
- Periodic Dots and Horizontal Streaks — If your marks appear as lines or bands rather than individual dots
- Black Marks on Back of Page — For toner marks on the reverse side of the sheet
- General Print Quality Troubleshooting Guide — Start here if you are not sure what type of problem you have
- Replacing the Image Drum
- Replacing the Fuser Unit
Still Having Issues?
If you have followed the steps above and the dots persist, contact Mediaset support. Attach a photo or scan of the affected print — ideally a solid colour test page — so we can identify the component remotely.
Mediaset Support: support@mediaset.no
Category: Print Quality Issues Tags: dots, spots, specks, white dots, black dots, image drum, fuser, transfer belt, print quality, OKI Applies to: OKI C650, C844, MC853, MC873, MC883, ES8453, ES8473, ES8483, Pro9431
Last updated: March 2026