Unwanted vertical parallel lines are being printed on documents

[ccmauricio]

Printed pages come out with vertical parallel lines. I have already carried out the cleaning procedure and the fault has not been eliminated.

[A_Gayathri]

Hi @ccmauricio,

Welcome to The HP Support Community.  

Thank you for posting your query, I will be glad to help you.

I understand you are facing vertical parallel lines on printed documents can be caused by a few different issues. 

Here are some troubleshooting steps to help resolve the problem with your HP Color LaserJet Pro MFP M177fw:

Check the Toner Cartridges:

• Remove the toner cartridges and inspect them for any damage or leaks. Ensure they are properly seated in their slots.
• Try shaking the toner cartridges gently to redistribute the toner evenly.

Inspect the Drum Units:

• The drum unit may be causing the lines if it's worn out or dirty. Carefully remove and inspect the drum for any visible damage or toner buildup.
• If the drum is dirty, clean it gently with a soft, lint-free cloth. Be careful not to touch the drum surface directly with your fingers.

Clean the Printer:

• Although you mentioned you’ve already performed a cleaning procedure, double-check to ensure all internal parts, especially the imaging drum and the toner areas, are clean. Use a soft brush or cloth to remove any remaining toner dust.

Check for Paper Issues:

• Ensure that the paper you are using is suitable for your printer and is loaded correctly. Sometimes, issues with the paper feed can cause streaks or lines.

Run a Printer Diagnostics:

• Many HP printers have a built-in diagnostic tool that can help identify and resolve printing issues. Look for a diagnostic or maintenance option in the printer’s menu.

Update or Reinstall Printer Drivers:

• Sometimes outdated or corrupted drivers can cause printing issues. Visit the HP website and download the latest drivers for your printer model. Install them and restart your computer.

Perform a Printer Calibration:

• Printer calibration can sometimes resolve issues with print quality. Look for the calibration option in your printer’s menu and follow the instructions.

Replace the Toner Cartridges or Drum:

• If none of the above steps work, it might be time to replace the toner cartridges or the drum unit. Even if they are not empty, they can sometimes be the cause of print quality problems.

Refer to this document: HP Color LaserJet Pro MFP M177fw User manual 

Fix Print Quality Problems for the HP Color LaserJet Pro MFP M176n and M177fw Printer Series

I hope this helps. 

Take care and have a good day.

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