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HP Color LaserJet Managed MFP E77428

Troubleshooting. Image Defects 2

Horizontal periodic light/dark band or dot

 

Step Cause Action
1 Horizontal periodic band (CR, 94.2 mm)
- OPC was left exposed for too long.
- OPC is damaged by a high voltage in a short amount of time.
This problem will resolve itself over time.
If the problem is not resolved, replace the drum unit.
2 Horizontal periodic light/dark band (Magnetic roller, 31.4 mm).
- The Magnetic Roller is in poor condition.
- V-groove of the Magnetic Roller surface is not uniform.
Replace the developer unit.

Foggy image

 

Step Cause Action
1 Voltage of OPC is abnormally low. Replace the Drum unit.
2 HVPS operates abnormally.
- HVPS is damaged or broken
Replace the HVPS board.
3 Toner is over supplied.
TC sensor operates abnormally.
Replace the toner cartridge.
4 Voltage of OPC is abnormally low.
- T1 voltage is abnormally high.
Check the T1 connection in the HVPS.
Check if the T1 roller spring in the ITB is connected correctly.
Replace the HVPS board.

Light image

 

Step Cause Action
1 Typical faulty images (TRC) operates abnormally. Perform TRC three to four times.
2 Poor transfer has occurred. Force a jam during the print job. Check the image on the image transfer belt (ITB). If the image on the ITB is normal, refer to the “Blurred image” section.
3 Toner is empty. Toner is abnormally supplied. Check if the toner level is sufficient. If not, replace the toner cartridge.
Check if the toner supply shutter is opened.
4 Output voltage of the HVPS is abnormally low.
- Color density decreases.
Replace the HVPS board.
5 TC down and toner spills. Replace the developer unit.
6 Toner spills by eraser. Check if the eraser is contaminated.
Replace the drum unit or developer unit.
Error Code
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