My 3100cn was working fine then I had to change the black toner, I didn't it exactly like the manual said to and now there is a clunking noise and it won't print from the multi tray, it just says paper jam, but I've checked everwhere and there is no paper stuck

SOURCE: Replace Toner message with new cartridge.

Ok, I got mine working again. Turns out there was about 2 cups of that crappy 3rd party toner all gummed up inside the mixing chamber just behind the metal roller. It was so jammed full of bad toner that the new dell toner couldn't even make it through to the roller. If you are feeling ambitious (and your printer is broken anyway) here is how I got mine working.

1. Turn off printer.
2. Pull the toner and drum out of the printer and rotate the carousel by hand until the black toner holder is at the top. 
3. Look on the right side of the carousel where the toner cartridge locks in. There is a white clip. Get a good flashlight and carefully examine how the clip works before you start prying on it. Gently pull back the small locking tab and rotate the clip towards you and remove it.  
4. Look on the other side, opposite where the white clip was. There is a small metal bracket held with a screw. Remove the screw and the bracket.
5. Now you can carefully lift the *entire black toner housing, roller and gearbox* of off the carousel. You may have to rotate the carousel slightly to maneuver it out.
6. Set the housing on a clean surface and remove the two screws that hold the scraper blade over the roller.
7. Dump out ALL the bad toner inside and clean off the roller with alcohol.
8. Dispose of bad toner and reassemble printer in the reverse order.

When reinstalling the blade you will need to set the gap between the blade and the roller so that a smooth, even layer of toner is spread across the roller as it turns. Too big a gap and your prints will be dark and smudgy. Too small and your prints will be light. I checked my other colors with a feeler gauge, they were all set to 0.018" from the factory. You can eyeball it if you have to but using a feeler gauge works a lot better.

Final step is to install a new Dell toner cartage and allow the printer to calibrate. With any luck your will be fully functioning again.

SOURCE: Dell 3100cn Printer will not print

I had to actually change the settings in Microsoft Word to resolve this problem.

If you go to page setup > paper source > there should be lists for "first page" and "other pages".

You can set this to "as per printer settings" and hopefully it should work.

childofsai

SOURCE: Dell 1815dn paper jam.

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

SOURCE: How do I remove all the Dell 3100cn toner cartridges

First open the top door, pulling out the drum. Leave the door open.Then open the front door.
Then close it slowly. While doing this, move the carousel. The carrousel is free while the
door closed and locked while it open.

SOURCE: Dell 3100cn laser printer poor print quality

It sounds like you've got contamination on the drum cartridge or on one of the toner cartridges.

I'm actually going to be installing black toner in my 3100cn in about 8 hours, so I'll inspect and clean each of the carts, and write up the process for you tonight.

Testimonial: "Thanks! I have gone through all the instructions on Tech support for the printer. All cartridges have been cleaned and drum has been cleaned. Guess "