HP7740 copy from glass produces all-black page, and scan from glass produces blank page

[Haynes3]

My HP 7740 produces an all-black page when I make a copy from the glass.  It makes a completely blank page when I scan from the glass.  However, it scans correctly when I use the feeder, and it prints correctly when I send documents from my computer to the printer to print.  I have uninstalled and reinstalled the printer, checked the firmware (which is the latest version), and restored factory defaults.  None of that has helped.  Do I need to take the printer to a repair shop, or is there some other solution?

[Kumar0307]

@Haynes3, Welcome to the HP Support Community! I’m here to help.

I understand you are not able to make copies or scan using the flatbed glass. This seems like an issue with the scanner mechanism.

The document feeder has a separate scanner and hence is not affected.

Reset the printer

1. With the printer turned on, disconnect the power cord from the rear of the printer.
2. Wait at least 60 seconds.
3. Reconnect the power cord to the rear of the printer.
4. Turn ON the printer, if it does not automatically turn on.
5. Wait until the printer is idle and silent before you proceed.

Note: HP recommends connecting the printer directly to a wall outlet rather than a surge protector or a power strip.

Check the scanner bar functionality

Perform a visual test of the scanner mechanism to see if it is jammed.

1. Remove any original documents or photos from the scanner glass.
2. Lift the scanner lid slightly, and then press the Copy button or icon.

If the scanner light does not move or moves halfway or is not lit, the scanner mechanism is likely jammed/broken.

In this case, I've sent you a private message with further instructions to resolve this issue.

• In order to access your private messages, click the private message icon on the upper right corner of your HP community profile, next to your profile Name or simply click on this link: https://h30434.www3.hp.com/t5/notes/privatenotespage

Hope this helps! Let me know how it goes. 

Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.

Click on the YES button to reply that the response was helpful and/or to say “Thank You”.

Have a great day! 

[Haynes3 · Accepted solution]

I was able to solve the problem by removing all of the print cartridges, and then putting them back in.  Apparently, one of the print cartridges or the capsule that holds the print cartridges had been pressing against the cable that pulls the scanning bulb under the glass, so the scanning bulb had not been moving under the glass.  The printer is working correctly now.