Paper jam rear, open back cover. Paper jam has been removed but message is still there and not allowing printing

To remove a paper jam from the exit rollers of a printer, you'll typically need to access the jammed area by opening the printer's covers. Keep in mind that the process can vary depending on the printer model and brand. Here are general steps you can follow to remove the cover and access the exit rollers:

1. Power Off the Printer: Before attempting to remove any jams or open the printer covers, make sure to turn off the printer and unplug it from the power source to avoid any risk of electrical shock.
2. Open the Printer's Top Cover: Most printers have a top cover that can be easily lifted to access the internal components. Look for a latch or release button on the printer's top cover and gently lift it up to open.
3. Locate the Jammed Paper: Once the top cover is open, carefully inspect the printer's internal area, especially around the exit rollers, for any visible jammed paper. If you find the jammed paper, gently grasp it and pull it out in the direction of paper movement to avoid damaging the printer.
4. Check the Rear Cover (if applicable): Some printers have a rear cover or panel that allows access to the exit rollers and other internal components. If your printer has a rear cover, you may need to open it to clear the jam completely.
5. Remove Paper Trays (if necessary): If the jammed paper extends into the paper trays, you may need to remove the trays to access and remove the jam more effectively.
6. Clear Paper Path: Ensure that all remnants of the jammed paper are cleared from the printer's paper path. Check for any small pieces of paper that may have torn during the jam and remove them as well.
7. Close the Covers: After you have successfully removed the jam, close all the printer covers securely. Make sure they are properly latched to ensure the printer functions correctly.
8. Power On the Printer: Plug the printer back into the power source and turn it on. Perform a test print to verify that the paper jam issue has been resolved.

1. Open the Outer Back(Rear) Cover (1) at the back of the machine. Pull the jammed paper out of the machine.
   
   
   
2. Close the Inner Back(Rear) Cover (1) if it is open as shown in the illustration.
   
   
   
3. Close the Outer Back(Rear) Cover. Make sure the cover is closed properly.
   
4. Pull the paper trays (1) out of the machine.
   
   
   
5. Push the two green levers up on both sides.
   
   
   
6. Pull out the jammed paper (1) and press Stop/Exit.
   
   
   
7. Push the green duplex unit up.
   
   
   
8. Reset the machine by lifting the scanner cover from the front of the machine and then closing it.
   If you cannot remove the jammed paper from the front of the machine, or the error message still appears on the LCD after you have removed the jammed paper, please go to the next step.
   
   
9. Using both hands, use the plastic tabs on both sides of the machine to lift the Scanner Cover (1) into the open position. Make sure that there is no jammed paper left in the corners of the machine under the plastic covers.
   
   
   Note
   
   • If ink gets on your skin or clothing immediately wash it off with soap or detergent.
     
     
   • If the paper is jammed under the print head, unplug the machine from the power source, and then move the print head to take out the paper.
     
     
   • If the print head has stopped in the right corner as shown in the illustration, you cannot move the print head. Press Stop/Exit until the print head moves to the middle. Then unplug the machine from the power source, and take out the paper.
   
   
   
   1. Gently close the scanner cover using the finger holds on both sides of it as you push down on the Scanner Cover Support (1).
      
   Caution Be careful not to trap your fingers under the scanner cover. Always use the finger holds provided on both sides of the scanner cover when opening and closing it.
   
   
   1. Push paper tray #1 and paper tray #2 firmly back into the machine.
      
      
   Note Make sure you pull out the paper support until it clicks.
   
   

This may help...
http://www.ehow.com/how_7197988_troubleshoot-canon-mp600-printer.html

You can access Canon online support info here. Enter paper jam as a search, then choose #4 to remove the obstruction.
Also see this:
Issue: Paper is jammed inside the printer
Solution: Removing paper jams MP600

Removing Obstructions or Jammed Paper If [Paper output slot - The paper is jammed. Clear the paper and press OK] appears on the LCD, follow this procedure to clear the paper jam Clearing paper jams from the auto sheet feeder (ASF) or paper output slot
Clearing paper jams inside the printer
Clearing credit card-sized or 4" x 6" paper jammed inside the printer

ASF / Paper Output Slot

1. Turn off the printer.
   
   
2. Remove paper from the ASF.
   
   
3. Gently pull the jammed paper out.
   
4. 1. If paper is visible from the ASF, use both hands to pull the paper out slowly.
      
   2. If paper is visible from the paper output slot, use both hands to pull the paper out slowly.
      
      The above illustration shows a PIXMA MP500.
      
      
5. If the paper tears and a piece of that remains inside the printer, open the scanning unit (printer cover) and remove the paper from inside the printer.
   
   Note:
   Be careful not to touch the components inside the printer.
   
   
   
6. Turn on the printer and confirm that the Alarm light is off.
   (If the jammed paper remains in the printer, the paper may be automatically ejected.)
   
   
7. Load paper back into the ASF.
   
   
8. Press <OK> to clear the message and continue printing. If you are printing from an application software, follow the instructions displayed on your computer.
   

Top
Paper jams inside the printer

1. Turn off the printer and disconnect the power cord and USB cable.
   
   
2. Remove the jammed paper slowly using the following procedure.
   
3. 1. Open the rear cover to check if the paper is jammed.
      
      
   2. Pull out the cassette and check if the paper is jammed inside the cassette area.
      
      
   3. Stand the printer with the left side down, holding the document cover.
      
   4. Press the tabs together and pull the green cover toward you.
      
   5. Check if the paper is jammed.
      (If you were not doing Duplex printing, you do not have to follow this procedure.)
      
      
   6. Close the green cover and place the printer back to a normal position.
      
4. Reconnect the power cord and power on the printer. Confirm the Alarm light is off.
   
   
5. Load paper back into the ASF or cassette.
   
   
6. Press <OK> to clear the message and continue printing. If you are printing from an application software, follow the instructions displayed on your computer.
   

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Clearing credit card-sized paper jammed inside the printer
Credit card-sized and 4" x 6" sized paper must be loaded properly. If this media is not loaded properly, it will feed into the printer and will not exit. Credit card-sized paper should only be loaded in the ASF and in portrait orientation. 4" x 6" sized paper can be loaded in the ASF or cassette. But must be loaded portrait orientation.
If credit card-sized paper was loaded in landscape orientation in the ASF and did not eject (exit), please follow this procedure.

1. Turn off the printer.
   
   
2. Load the same paper type that is jammed inside the printer in portrait orientation.
   
   
3. Power on the printer.
   The paper stock in the ASF will automatically feed the jammed paper from the printer.
   
   
4. To resume printing, load the paper in portrait orientation.

If 4" x 6" sized paper was loaded in landscape orientation in the cassette and did not eject (exit), please follow this procedure.

1. Turn off the printer.
   
   
2. Open the rear cover.
   
   
3. Fold in four a piece of letter-sized plain paper.
   
   
4. Push in the folded paper until it hits the jammed paper.
   
   
5. If the jammed paper is visible from inside the printer area, pull it out and proceed to step 7.
   
   
6. If the jammed paper cannot be pulled out, push in the folder paper from the rear so the jammed paper is in between the feed rollers.
   
   
7. Pull out the folded paper and close the rear cover.
   
   
8. Power on the printer and confirm that the Alarm light is off.
   The jammed paper should automatically eject.
   
   
9. To resume printing, load the paper in portrait orientation.

I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks

HP Officejet 7200, 7300, and 7400 Series - 'Paper Jam: Clear jam, and then press Enter' Message Displays on the Control Panel Display
Issue
During printing, the paper becomes stuck in the all-in-one and the error message 'Paper Jam: Clear jam, and then press Enter' displays on the control panel display.
Solution
Use the following instructions to clear a paper jam from the product:
Step one: Check for and remove any loose paper from the In tray
Do not try to remove jammed paper from the In tray. First remove any loose paper from the In tray to avoid worsening the jam.
CAUTION: Always try to remove jammed paper from the back of the printer first to avoid mechanical damage.
Step two: Clear the jam from the back of the printer
Follow these instructions to clear jammed paper from the back of the product. If the product is equipped with a two-sided printing accessory, skip to that section.
Remove the rear access door to clear the paper jam

1. Remove the rear access door by pressing the buttons on the side of the door and pulling it toward you.
Figure 1: Removing the rear access door
Rear access door
2. Gently pull the jammed paper out of the rollers.
WARNING: If the paper tears while removing it from the rollers, check the rollers and wheels for torn pieces of paper that might remain inside the product. If all the pieces of paper are not removed from the product, more paper jams might occur.
3. Replace the rear access door. Gently push the door into the all-in-one until it snaps firmly into place.

Remove the two-sided printing accessory to clear the paper jam

1. Remove the two-sided printing accessory by pressing in the buttons on the sides and then pulling the accessory toward you.
Figure 2: Removing the two-sided printing accessory
2. Gently remove any jammed paper.
WARNING: If the paper tears while removing it from the rollers, check the rollers and wheels for torn pieces of paper that might remain inside the accessory. If all the pieces of paper are not removed from the accessory, more paper jams might occur.
3. Press the button on top of the two-sided printing accessory to open the door.
Figure 3: Opening the two-sided printing accessory door
4. Gently pull the jammed paper out of the rollers.
5. Close the accessory door.
6. Reinstall the two-sided printing accessory.

Step three: Clear the jam from the automatic document feeder (ADF)

1. Remove the document feeder tray from the product by gently pulling it.
2. Lift the cover of the automatic document feeder by pulling it outward.
Figure 4: Lifting the cover of the automatic document feeder
Automatic document feeder (ADF) door
3. Gently pull the jammed paper out of the rollers.
WARNING: In the rare occurrence of a severe paper jam, you might need to remove the face plate from the front of the automatic document feeder and lift the pick assembly to remove torn pieces of paper from deep inside the automatic document feeder.
4. Close the cover of the automatic document feeder, and then reattach the document feeder tray.

Step four: Verify that the print carriage can move freely
Follow these steps to try to move the print carriage.
CAUTION: Do not force the print carriage to move if it is out of plain view or feels stuck. Forcing it may damage the printer.

1. With the product turned on, open the print cartridge access door. The print carriage might try to move into the access area. If so, allow it to move to that position.
2. Without turning off the product, unplug the power cord from the back of the product. Unplug the power cord from the power source. The power cord must be unplugged to allow the parts to be moved by hand and to reset the paper feed mechanism, without the risk of an electrical shock.
3. Looking in through either the print cartridge access door or the output paper tray, make sure the print cartridges are locked into the carriage and have not come loose. Also, make sure that there are no obstructions under or around the carriage to block it from moving.
4. Make sure the print carriage can move freely across the width of the product by gently pushing the carriage to the left and then to the right. Clear any obstructions found.
You may have to reach through the output paper tray to access the print carriage.
5. Close the print cartridge access door and plug the power cord back to the back of the product. Plug the power cord into the power source.
6. Press the On button to turn on the product.

Step five: Reload and test the printer
After you have removed the jammed paper, make sure the product is still functioning properly.

1. Reload the product with plain paper.
2. Peform a self-test by pressing and holding the RESUME button on the control panel until the product begins printing. A test page prints.

Step six: Service the printer
If you have completed all the steps listed above and are still experiencing a problem, service the product.

Hi

Thanks for using FixYa. Before you can clear the error message, you must locate where in the unit the paper is jammed.

Unplug the machine for safety. Now follow these instructions based on where the paper jam is located.

1. Pull the paper tray out of the machine.
2. Pull out the jammed paper.
3. Reset the machine by opening the Upper Jam Clear Cover and then closing it.

If you cannot remove the jammed paper from the front of the machine, or the error message still appears on the LCD after you have removed the jammed paper, please go to the next step.

4. Remove the Lower Jam Clear Cover from the back of the machine. Pull the jammed paper out of the machine.

5. Put the Lower Jam Clear Cover back on. Make sure the cover is set properly.

6. Open the Upper Jam Clear Cover. Make sure that there is no jammed paper left in the corners of the machine.
Note: If the paper is jammed under the print head, unplug the machine from the power source, then move the print head to take out the paper. 7. Close the Upper Jam Clear Cover.

8. Close the output paper tray cover and slide it forward, then push the paper tray firmly back into the machine. While holding the paper tray in place, pull out the paper support until it clicks and unfold the paper support flap.

Please do rate the solution and revert for further assistance.

Thanks
Rylee

You can access Canon online support info here. Enter paper jam as a search, then choose #4 to remove the obstruction.
Also see this:
Issue: Paper is jammed inside the printer
Solution: Removing paper jams MP600

Removing Obstructions or Jammed Paper If [Paper output slot - The paper is jammed. Clear the paper and press OK] appears on the LCD, follow this procedure to clear the paper jam Clearing paper jams from the auto sheet feeder (ASF) or paper output slot
Clearing paper jams inside the printer
Clearing credit card-sized or 4" x 6" paper jammed inside the printer

ASF / Paper Output Slot

1. Turn off the printer.
   
   
2. Remove paper from the ASF.
   
   
3. Gently pull the jammed paper out.
   
4. 1. If paper is visible from the ASF, use both hands to pull the paper out slowly.
      
   2. If paper is visible from the paper output slot, use both hands to pull the paper out slowly.
      
      
      The above illustration shows a PIXMA MP500.
      
      
5. If the paper tears and a piece of that remains inside the printer, open the scanning unit (printer cover) and remove the paper from inside the printer.
   
   Note:
   Be careful not to touch the components inside the printer.
   
   
   
6. Turn on the printer and confirm that the Alarm light is off.
   (If the jammed paper remains in the printer, the paper may be automatically ejected.)
   
   
7. Load paper back into the ASF.
   
   
8. Press <OK> to clear the message and continue printing. If you are printing from an application software, follow the instructions displayed on your computer.
   

Top
Paper jams inside the printer

1. Turn off the printer and disconnect the power cord and USB cable.
   
   
2. Remove the jammed paper slowly using the following procedure.
   
3. 1. Open the rear cover to check if the paper is jammed.
      
      
      
   2. Pull out the cassette and check if the paper is jammed inside the cassette area.
      
      
      
   3. Stand the printer with the left side down, holding the document cover.
      
   4. Press the tabs together and pull the green cover toward you.
      
   5. Check if the paper is jammed.
      (If you were not doing Duplex printing, you do not have to follow this procedure.)
      
      
      
      
   6. Close the green cover and place the printer back to a normal position.
      
4. Reconnect the power cord and power on the printer. Confirm the Alarm light is off.
   
   
5. Load paper back into the ASF or cassette.
   
   
6. Press <OK> to clear the message and continue printing. If you are printing from an application software, follow the instructions displayed on your computer.
   

Top

Clearing credit card-sized paper jammed inside the printer
Credit card-sized and 4" x 6" sized paper must be loaded properly. If this media is not loaded properly, it will feed into the printer and will not exit. Credit card-sized paper should only be loaded in the ASF and in portrait orientation. 4" x 6" sized paper can be loaded in the ASF or cassette. But must be loaded portrait orientation.
If credit card-sized paper was loaded in landscape orientation in the ASF and did not eject (exit), please follow this procedure.

1. Turn off the printer.
   
   
2. Load the same paper type that is jammed inside the printer in portrait orientation.
   
   
   
   
3. Power on the printer.
   The paper stock in the ASF will automatically feed the jammed paper from the printer.
   
   
4. To resume printing, load the paper in portrait orientation.

If 4" x 6" sized paper was loaded in landscape orientation in the cassette and did not eject (exit), please follow this procedure.

1. Turn off the printer.
   
   
2. Open the rear cover.
   
   
3. Fold in four a piece of letter-sized plain paper.
   
   
4. Push in the folded paper until it hits the jammed paper.
   
   
   
   
5. If the jammed paper is visible from inside the printer area, pull it out and proceed to step 7.
   
   
6. If the jammed paper cannot be pulled out, push in the folder paper from the rear so the jammed paper is in between the feed rollers.
   
   
7. Pull out the folded paper and close the rear cover.
   
   
8. Power on the printer and confirm that the Alarm light is off.
   The jammed paper should automatically eject.
   
   
9. To resume printing, load the paper in portrait orientation.

I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks!

usual problem is a paper sensor (most likely a small lever) has gotten stuck.. find the paper sensors and reposition them

You need to reset the printer software.

Try this linke below.
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=110&prodSeriesId=411171&prodTypeId=18972&prodSeriesId=411171&objectID=c00642524

Or i cut and paste text, but you should view pictures. If you cannot get to it from link. Try typing "Paper jams alternating between front and back door" It should be first link from HP about a 3550.

document.tlSearch.tx.value=unescape("")
HP Color LaserJet 3500, 3550, and 3700 Series Printers - Paper Jams Alternating Between Front and Back Door Issue Description Customers may see paper jams error messages with no paper seen in the paper path. The message will alternate between check the front door and the back door. Workaround The release lever engagement tabs on the rear door can be bumped into the in-correct position. The purpose for this tab is to re-engage the fuser release levers as the rear door is closed. When one or both of these are left in the in-correct position the printer goes into a cycle of alternating between a "Jam in the Front Door" message and "Jam in the Rear Door" message. There is no paper present in the paper path when this happens. When a customer gets the "Jam in the Front Door" message and opens the front door, no paper is found. After the customer closes the front door, they get the "Jam in the Rear Door" message. When they open the rear door, find not paper (even pull out the fuser), and close the rear door, they get the "Jam in the Front Door" message. This cycle will continue

Placing both engagement tabs in the "Correct" position solves the problem and allows the print job to continue.for as long as the customer is willing to keep checking.