Paper Size Mismatch

[mor3dr3ad]

Printer has suddenly stopped printing (including diagnostic pages), coming up with a paper mismatch error. I've loaded A4, gone into settings both in the printer and application and checked settings are OK. This happens only when printing, copying works fine.

I have checked inside the printer and can see no debris or misaligned flaps or anything. I have reset the printer (removing the power cord for 60 secs), done a factory reset, checked driver and firmware which are all up to date.

I have checked the default settings in the browser and on the printer itself and ran through the suggestions on the HP Support video. It's almost like the sensor can't pick up what size the paper is. Is there a way to check the sensor is working?

[Raj_05]

Hi @mor3dr3ad,

Welcome to HP Support Community.

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

It seems like you've already gone through extensive troubleshooting for your HP OfficeJet Pro 7720, but since the issue might be related to the sensor not recognizing the paper size correctly, I can suggest a few additional steps that might help narrow down the issue.

Check Paper Settings Again (on PC and Printer)

Ensure that both the printer and the print settings on your PC are set to A4. Sometimes, one might default to a different paper size (e.g., Letter).

Printer Control Panel:

• Go to Settings > Paper Setup > Default Paper Size and make sure it's set to A4.

Print Settings on PC:

• When you print from any application, go to Print > Properties and verify that A4 is selected under paper size.

Inspect Paper Size Sensors

While there’s no direct method to test the paper size sensor at home, the following steps might help:

Clean the Paper Sensors: Dust or paper debris can sometimes cause the sensor to misread the paper size. Use a soft cloth and gently clean the paper tray, making sure to get inside areas where the sensor might be located.

Test with Different Paper: Try using a different stack of A4 paper or a different size (such as Letter) to see if the printer recognizes other sizes. This can help rule out whether it's an A4-specific issue.

Printer Firmware Reset (Cold Reset)

Since you've done a factory reset, you might want to try a cold reset if the printer supports it:

1. Power off the printer.
2. While it's off, press and hold the Resume button (or similar button on the front panel).
3. Continue holding it while powering the printer back on.
4. Release the button once the printer starts.

This might recalibrate the printer’s internal sensors.

Check for Paper Tray Issues

Ensure that the paper tray itself is seated correctly and isn't damaged. Some users report that a slightly misaligned tray can cause issues with paper recognition.

Driver Conflicts

Try uninstalling and reinstalling the printer drivers:

1. Uninstall the Printer from your PC.
2. Download the latest driver from the HP website.
3. Reinstall it and test.

[Raj_05]

HP Print and Scan Doctor

Download the HP Print and Scan Doctor from the HP website. This tool is specifically designed to identify and resolve many common printing issues, including paper mismatch errors.

I hope this helps.

Take care and have a good day.

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!

Alden4

HP Support 

[mor3dr3ad]

Hi, Alden4 and thanks,

I have tried printing both from a laptop and a mobile device with the same effect. So I can rule out a Settings Issue.

Happy to look at the paper sensors. However, I do not know how they look like and where they are situated. Can you give me a hint? I have visually inspected the inside and the paper tray and can find nothing misaligned. However, I am not a HP technician.

[mor3dr3ad]

will try do this, but have to get my hands on a windows machine first

[Raj_05]

Hi @mor3dr3ad,

Thank you for your response, 

Paper Sensors in HP OfficeJet Pro 7720

In printers like the HP OfficeJet Pro 7720, paper sensors are typically located in the paper tray and paper path. They detect the size and type of paper loaded. Here’s how to locate and check them.

Paper Tray Sensors

• Location: The paper tray sensors are usually at the back or sides of the paper tray. They help detect the size of the paper based on the position of the paper guides.
• What to Look For:
  • Make sure the paper guides in the tray are correctly aligned with the paper size. The guides should snugly fit the paper without bending or squeezing it too tightly.
  • Inspect the tray for any visible debris, broken plastic tabs, or anything obstructing the sensors.

Inside the Printer

• Location: Inside the printer, you’ll find sensors along the paper path, including around the print carriage and where the paper exits.
• What to Look For:
  • Open the printer and look near the print head and rollers for any paper debris, dust, or small obstructions.
  • These sensors are typically small plastic tabs or levers that detect paper as it passes. Check if any are stuck or broken.

Manual Reset of Paper Size

• In some cases, reloading the paper and resetting the size manually in the printer’s settings can help:
  1. Turn off the printer, remove the paper tray, and reload the paper.
  2. Power the printer back on.
  3. Manually select the correct paper size through the printer’s control panel.

Clean Rollers and Sensors

• Cleaning the paper rollers and sensor areas can also help resolve paper mismatch errors. Gently wipe the rollers and check the sensors for dust or dirt that may be causing false readings. 

I hope this helps.

Take care and have a good day.

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!

Alden4

HP Support

[mor3dr3ad]

Dear Alden4,

thank you very much for your support. I have checked everything visually and have not found any debris or broken parts. The levers all seem to be moving and - from visual inspection - functional. I have noticed that the rollers (supposedly those that draw in/move forward the paper) are a little dirty; I will try cleaning them carefully but do not think that this will make a difference.

However, this is weird in itself, because copying works. So apparently when copying the paper format is recognized?

[Raj_05]

Hi @mor3dr3ad,

Thank you for your response, 

It sounds like you've done a thorough visual inspection and checked for obvious mechanical issues with your HP OfficeJet Pro 7720. The fact that copying works but other paper-related functions don’t suggests that the rollers and paper sensors may be functioning, but there could be other underlying issues with the device's communication between different functions.

Here are a few additional steps you can try to troubleshoot:

Clean the Rollers

Even if the rollers don’t appear excessively dirty, cleaning them can still make a difference. Use a lint-free cloth slightly dampened with water and gently wipe the rollers. If they are too smooth or dirty, they might struggle with paper feeding during non-copying functions.

Paper Format Detection

Since copying works, the paper format sensors are likely functional during that mode. However, if the printer is not recognizing paper formats in other modes (like printing or scanning), it could be a software or settings issue. Make sure the paper size settings are consistent across the printer's settings and the software you're using to print.

Reset the Printer

Perform a full factory reset. Sometimes, resetting the device to factory defaults can resolve odd software bugs.

Update Firmware/Drivers

Ensure that the printer’s firmware is up to date. Firmware glitches can cause problems with paper handling and other internal functions. Similarly, update or reinstall printer drivers if you’re printing from a PC or other device.

Test Different Functions

• Try printing from different sources (directly from the printer, from a computer, or a mobile device).
• Try scanning directly from the printer.
• Run any available internal diagnostics to see if the printer logs any errors.

I hope this helps.

Take care and have a good day.

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!

Alden4

HP Support