When receiving a FAX or printing a receipt, it repeatedly jams. The paper is found inside the back cover baked into a folded fan shape.

to clear document jam:
1 Open the front panel.
2 Carefully remove the jammed document.
3 Close the front panel firmly until it clicks
into place.

If the fax paper jams while you are receiving or printing, Remove jammed paper and press
Cancel appears in the message.

if the paper is jammed in the printing area
1 Remove the jammed paper by pulling it out
smoothly in the direction of the arrow as
shown.
If the paper tears when it is being removed
check to ensure that no small pieces have
been left inside the machine.
2 Press Cancel.
3 If this was a fax, reprint the fax. For more
information, see reprinting faxes on
page 29.

if the paper is jammed in the paper feed
area
1 Remove the jammed paper as shown.
If the paper tears when it is being
removed check to ensure that no small
pieces have been left inside the machine.
2 Reload new paper with the print side
facing toward you.
3 Press Cancel when finished.

If you take the paper tray out you will see there is a back roller in the middel of the m/c. clean that roler with soupe.

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.
   

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

Hello

Most error codes can be cleared by removing the paper jam and then rebooting the machine. When an error code occurs, make a note of the code and then follow the instructions on the control panel for clearing it.

Paper jams can be caused by a variety of issues in the copy machine, but jamming can commonly be caused by improperly loaded paper in the trays or dirty paper feed rollers.

If you get repeated paper jams, remove the paper from the trays and inspect the stack. Look for folded corners, especially on the bottom of the stack. Fan the paper thoroughly and then reload the stack into the tray. Check the paper guides to ensure they are not too tight or too loose. Both conditions can cause paper jams.

If you can see the paper transport rollers by opening the ordinary access covers and panels inside the machine, cleaning them might help reduce paper jams. Shut the machine off and unplug it, then take a soft, lint-free cloth dampened with water and wipe those rollers off. A buildup of toner and paper dust can cause them to slip while transporting the paper.

Hi
Error 6A00
The 6A00 is a Canon generic code for paper path jam.

Solution 1:
Move the printhead carriage back and forth a few times.

Solution 2:
Check the purge unit: Moving the print head assembly will not clear a purge unit if its jammed with paper, paper clips, push pins, screws, cookie crisp, flower bud pods or the like.

Solution 3:
Press the ink pads down in the purge unit.

All I ask is please come back and just gave a vote, it will gave me some satisfaction to know am helping some one so I will keep on helping.
All The Best: Pineworks

the printer roler settings have changed or the roller has gone faulty ... get the printer serviced

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!

THERE IS SOME THING BLOCKING THE PAPER PATH, MAY BE PAPER OR SOME THING FELL IN THE MACHINE GOOD LUCK BROTHER TECH

look at the paper tray,some of your sensor are jammed,try tyo find out where is the sensor on paper try