How to remove paper jam from duplex unit

This is from the user guide available on the HP.com website:
This section contains the following topics:
• Clear paper jams
• Avoid paper jams
Clear paper jams
Paper jams can occur either inside the printer or in the automatic document feeder.
CAUTION: To prevent possible damage to the printhead, clear paper jams as
soon as possible.
TIP: If you notice poor print quality, clean the printhead. For more information, see
Clean the printhead.
Use these steps to clear a paper jam.
To clear a jam inside the printer
1. Remove all media from the output tray.
CAUTION: Trying to clear a paper jam from the front of the printer can
damage the print mechanism. Always access and clear paper jams through
the automatic two-sided printing accessory (duplexer).
2. Check the duplexer.
a. Push the button on either side of the duplexer, and then remove the unit.
b. Locate any jammed media inside the printer, grasp it with both hands and
then pull it towards you.
c. If the jam is not there, push the latch on top of the duplexer and lower the
cover. If media is jammed inside, carefully remove it. Close the cover.
d. Reinsert the duplexer into the printer.
3. Open the top cover and remove any debris.
4. If you have not found the jam and have Tray 2 installed, pull out the tray and
remove the jammed media, if possible. If not, do the following:
a. Ensure the printer is turned off and disconnect the power cord.
b. Lift the printer off Tray 2.
c. Remove the jammed media from the bottom of the printer or from Tray 2.
d. Reposition the printer on top of Tray 2.
5. Open the ink cartridge access door. If there is paper remaining inside the printer,
ensure the carriage has moved to the right of the printer, free any paper scraps or
wrinkled media, and pull the media towards you through the top of the printer.
WARNING! Do not reach into the printer when it is on and the carriage is
stuck. When you open the ink cartridge access door, the carriage should
return to its position on the right side of the printer. If it does not move to the
right, turn off the printer before you remove any jam.
6. After clearing the jam, close all covers, turn on the printer (if you turned it off) and
resend the print job.

That's about as much as I can find for you. If you look in you user guide which is on a CD that came with the unit, you can go to page 152 through 154 to see diagrams that go with these instructions. Good luck!

Have you read the Manual on paper removal? It mentions a rear panel that can be removed. That might free up the rollers:
If the paper jam is near the paper input tray:
1. Remove the paper tray.
2. Pull firmly on the paper to remove it.
3. Replace the paper tray.
4. Press the Select button .
5. Resend your print job to print any missing pages.
If the paper jam is not visible:
1. Turn off the printer.
2. Lift the printer unit.
3. Firmly grasp the paper, and gently pull it from the printer.
4. Close the printer unit.
5. Turn on the printer, and print the document again.
If the jam is located in the duplex unit or near the rear access door:
1. If you have a duplex unit, remove it.
2. Open the rear access door.
3. Firmly grasp the paper, and gently pull it from the printer.
4. Close the rear access door.
5. Re-install the duplex unit.
6. Press the Select button to continue printing.
If the paper jam occurs near the ADF:
1. Lift the ADF cover located to the left of the ADF input tray.
2. Firmly grasp the paper, and then gently pull it from the printer.
3. Close the ADF cover.
4. Press the Select button .
5. Resend your print job to print any missing pages.

Hi, please try this:

1. Remove all media from the output tray.
2. Check the duplexer.

a. Push the button on either side of the duplexer, and then remove the panel or unit.

b. Locate any jammed media inside the device, grasp it with both hands and then pull it towards you.
c. If the jam is not there, push the latch on the top of the duplexer and lower its cover. If the jam is inside, carefully remove it. Close the cover.




d. Reinsert the duplexer into the device.

3. Open the top cover and remove any debris.
4. If you have not found the jam and have Tray 2 installed, pull out the tray and remove the jammed media, if possible. If not, do the following:

a. Ensure the device is turned off and disconnect the power cord.
b. Lift the device off Tray 2.
c. Remove the jammed media from the bottom of the device or from Tray 2.
d. Reposition the device on top of Tray 2.

5. Open the print carriage access door. If there is paper remaining inside the device, ensure the carriage has moved to the right of the device, free any paper scraps or wrinkled media, and pull the media towards you through the top of the device.

6. After clearing the jam, close all covers, turn on the device (if you turned it off) and resend the print job.


This is based on the HP 8500 manual. I hope this helps.

Hi,
If you are experiencing paper jam problem with your printer, please follow these steps: 1. Remove any loose sheets of paper from the input tray and the output tray. 2. Press the Power button ( ) to turn off the product. 3. Disconnect the power cord from the rear of the product. 4. Unplug the power cord from the wall outlet. 5. Turn the product around so that you can access the rear side. 6. Push in the button on either side of the two-sided printing accessory (duplexer), and then remove the duplexer. 7. Gently remove any jammed paper or bits of torn paper from the rollers inside the product. Use both hands to pull any whole sheets of paper to avoid tearing them. 8. If you do not see jammed paper in the rear access area, push the buttons on the latch on the rear of the duplexer, and then lower the cover. 9. Remove any jammed paper from inside the duplexer. 10. Close the duplexer cover. 11. Gently push the duplexer into the product until it snaps firmly into place. Do not press the buttons on the end of the accessory while you reattach it. 12. Reconnect the power cord to the rear of the product. 13. Plug the power cord back into the wall outlet. 14. Press the Power button ( ) to turn on the product.
If you need any further assistance, please comment back.

Follow these steps in the order presented to resolve the paper jam. Step one: Remove any loose paper Remove any loose sheets of paper from the input tray and the output tray. CAUTION: Do not remove jammed paper at this stage. Trying to clear jammed paper from the front of the product can damage the print mechanism. Remove any loose paper Do not pull jammed paper Step two: Clear the jam from the rear of the product CAUTION: Never pull jammed paper from the front of the product. If you can pull it from the rear of the product or the tray, always try the rear first. Pulling paper from inside the front cover can cause mechanical damage to the product.

1. Press the Power button ( ) to turn off the product.
2. Disconnect the power cord from the rear of the product.
3. Unplug the power cord from the wall outlet.
4. Turn the product around so that you can access the rear side. Figure 1: The rear side of the product
5. Push in the button on either side of the two-sided printing accessory (duplexer), and then remove the duplexer. Figure 2: Remove the duplexer 1 - Press the buttons on the sides of the duplexer 2 - Pull the duplexer out of product
6. Gently remove any jammed paper or bits of torn paper from the rollers inside the product. Use both hands to pull any whole sheets of paper to avoid tearing them. Figure 3: Gently remove the jammed paper CAUTION: Use a flashlight to thoroughly check the rollers and wheels for torn pieces of paper that might remain inside the product. If any torn pieces of paper remain inside the product, more jams are likely to occur. Figure 4: Remove scraps of paper
7. If you do not see jammed paper in the rear access area, push the buttons on the latch on the rear of the duplexer, and then lower the cover. Figure 5: Open the duplexer 1 - Latch on rear of the duplexer 2 - Duplexer cover
8. Remove any jammed paper from inside the duplexer.
9. Close the duplexer cover.
10. Gently push the duplexer into the product until it snaps firmly into place. Do not press the buttons on the end of the accessory while you reattach it. Figure 6: Reattach the duplexer
11. Reconnect the power cord to the rear of the product.
12. Plug the power cord back into the wall outlet.
13. Press the Power button ( ) to turn on the product.

Step three: Print a self-test report Follow these steps to print a self-test report. Printing a self-test report verifies if the hardware functions correctly.

1. Load unused, plain white paper in the input tray.
2. Press the Power button ( ) to turn on the product.
3. Press the Setup button ( ).
4. Press the Right Arrow ( ) to select Print Report , and then press OK .
5. Press the Right Arrow ( ) to select Self-Test Report , and then press OK . The self-test report prints.

Follow the instructions in this video. If you follow those instructions and still get the message, you may need to replace your printer or the rear door.

If you have tried the Kodak standard instructions for clearing the paper jam problem and it did not help try the procedure below.
1. Open the printing area of the printer (containing the ink cartridges).
2. The Ink cartridge holder should be to right side of track.
3. Look on left side, below the track for the cartridge that is used to
clean the print heads.It can be identified by a square black pad
approx. 1" sqaure that appears to be made of "felt".
If it is visible this is most likely your problem.
4. To correct problem locate the flat latching lever approx. 3/4" wide that
sticks up about 1/2" above the cartridge. It is locacted just behind
the "felt" square. Gently push lever toward rear which should free the
cleaning cartridge and allow the entir cartridge to move slightly
backward.
5. Close the top of the printer and cycle the printer off and back on.
If this is the problem, the "paper jam" error will now be gone.
This is such a simple fix I do not know why kodak does not inform
customers of this problem and how to fix it.

you should be able to gain access to where the paper is jammed if you remove the paper tray, then remove the duplex assembly. However, if the jam is further inside the unit, you will need to remove the highvoltage power supply to gain access to that area. I have provided the instructions for both.

To remove the duplex assembly, orient the printer so you are looking at the back of the unit,
Grasp the duplex unit handle and pull it toward you.

Next...Orient the printer with the front cover face down on the surface and the bottom of the chassis facing you as shown below.





If you still can not get the paper out, then you will need to further disassemble the unit by removing the high voltage power supply. This will expose the rollers located underneath. See below...

Remove the HVPS securing screws.

Rotate the HVPS down until the cables can be accessed.

Disconnect the HVPS cables.



Remove the HVPS from the chassis.

Please take a moment to rate this solution as "fixya" if you feel I have successfully answered your question.

Thanks

This is an awesome printer. Did you know it can duplex (print on both sides of the paper) automatically? The jam "could" be in the duplexer on the back or, the duplexer unit isn't locked into place.

Unplug the printer and open the rear door, check for visible paper jam, remove, close door.

There's also access to the feed mechanism from the bottom of the printer.

Unplug printer.

(1) Remove the Cassette. (paper tray on bottom of printer)

If the paper is loaded in the Auto Sheet Feeder (on back of printer), remove the paper from the Auto Sheet Feeder and close the Paper Support.
(2) Stand the machine with the left side down.
(3) Slowly pull the jammed paper out while pulling the green cover toward you.


Caution
Set the machine back to its original position immediately after removing the jammed paper.
(4) If any paper is sticking out of the Cassette, reload the paper in the Cassette.
Reload paper in the Auto Sheet Feeder, if necessary.
(5) Insert the Cassette into the machine.
(6) Press the OK button on the machine.


Some of these instructions were copied from the online/downloadable printer manual from Canon's web site: http://www.usa.canon.com/consumer/