-Fitted new black cartridge and cleaned several times but print still smudged

Toner cartridge no longer any good. Needs to be replaced.

Hi
First before you buy a new cartridge,try doing a 'printhead' cleaning on your machine.Sometimes the printheads need cleaning clogginl.

If this just started after you replaced the toner cartridge, one would have to say that it is a bad toner cartridge.
Print something that smudges. Pull down the front cover and look at the cartridges. Pay attention to the top one(black).
Look at the drum on that cartridge. You should see the toner sitting there. Compare it to the other cartridges which should be clean.

How do I clean white or black spots on printed documents? Description: First make 10 to 15 copies of a blank, white sheet of paper.
If you still see the spots on printed documents after making multiple copies, clean the drum unit as follows:

1. Remove the drum unit and toner cartridge assembly, and then remove the toner cartridge from the drum unit.
   
2. Position the print sample in front of the drum unit so you will know the exact position on the drum that is causing the poor print.
   

3. Turn the black gear on the drum as you check the surface of the OPC drum.
   The OPC drum is photosensitive so do not touch it with your fingers.
   

4. When you find the substance on the drum surface that matches the print sample, gently dab the surface of the OPC drum with a cotton swab that is lightly dampened with isopropyl alcohol.
   
Note
• Do not use a scrubbing or wiping motion because this might damage the drum.
  
• Do not try to clean the surface of the OPC drum with a sharp object, such as a ball-point pen, because this might cause permanent damage to the drum unit.
5. If the print quality still has not improved you need to install a new drum.
   

Arouse to press cartridge to contact, clean contacts and reinstall driver

This may be the cartridge itself, take the black ink cartridge out and check the head on it (the part that points in to the printer, usually down) and see if it is dirty or has ink smudges on it.

you may try
1) clean the cartridge nozzles with dry soft paper
2) clean the cartridge carriage down side surface there might be bled ink.
3) check the cartridge up side there is the lable cover the ink refill hole is ok, no any lable stick there you need put stick lable there.

I had the same problem when i refilled my cartridge. All I did to solve it was this: I removed the cartridge from the printer and cleaned the green cylinder with a very soft cloth. There is a cogwheel on both sides of the cylinder, so you can move the cylinder by turning the cogwheel. On my cartridge there were a few, hard ink-spots, i had to rub a little to wipe them off. When I removed them, the problem was solved.

ok, What cartridges are you using, Are the Canon cartridges?
What paper are you using, is it Canon paper?

If you are to both of these it could be wise ordering a printhead, but this is mostly caused in the uk by None Canon Paper.

Please let me know what you are using?

just remove the colour catridge and then see is it working with single catridge .