Cleaning an HP Office Jet Pro 7740

[The_Plan_Man]

How can I clean the underside (or "backside" or "inside") of the glass on my printer?

[Nal_NR]

Hi @The_Plan_Man,

Welcome to the HP Support Community. 

I'd be glad to help you! 

• Are you noticing specific streaks, lines, or marks on scanned or copied documents, or is it just a general haze?
• Have you tried any other cleaning methods, such as cleaning the exterior of the glass, to confirm the issue is on the inside?
• Have you recently opened the scanner or had any repairs that might have exposed the interior of the glass to dust?

Let's try these steps. 

Turn Off and Unplug the Printer:

• Always ensure the printer is powered off and unplugged before attempting any cleaning to avoid damage or injury.

Check the Printer Manual for Disassembly Instructions:

• Some models provide instructions for accessing the underside of the glass panel. Refer to your HP OfficeJet Pro 7740 manual or the HP Support website for guidance on safe disassembly.

Carefully Remove the Glass (If Applicable):

• If the manual allows it, locate the screws or latches holding the scanner glass in place. Remove them carefully to access the underside.
• Avoid touching delicate components, such as the scanner bar, while opening the panel.

Clean the Glass with a Soft Cloth:

• Use a lint-free microfiber cloth slightly dampened with glass cleaner or isopropyl alcohol (never spray directly onto the glass).
• Wipe gently to avoid scratching the surface. Let it dry completely before reassembling.

Reassemble and Test:

• Reattach the glass and any components you removed. Ensure everything is secure and properly aligned.
• Plug the printer back in, power it on, and run a test scan to see if the issue is resolved.

• If You Can’t Access the Underside Safely: Avoid forcing the scanner open. Instead, consult HP Phone Support 
• Check for Protective Film: Sometimes, residue from an adhesive or protective film may appear like internal smudges. Inspect the edges carefully.

YOu may also refer to this document for print quality issues. 

Also, try updating the firmware. Click here

Hope this helps! Keep me posted for further assistance

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