My iP6700D won't print black either!

In all likelihood your print head has become clogged at the black ink outlet. Be aware that printheads can BURN OUT if you keep trying to print and there's insufficient ink reaching the printhead. The ink flow is relied upon to prevent overheating of the tiny resistors at the printhead. Best bet is to remove the cartridges from the printhead and then remove the printhead and try to clean it in warm water. You will find many youtube videos on suggestions for cleaning the printheads on HP printers. Do a google search for your model. If all else fails you can order replacement printheads for the part that has failed. They are not cheap so price compare. Oftentimes they will cost nearly as much as a new printer!

Are you using original cartridge

Try this to unclog printhead.
take out cartridge, locate the hole where ink goes trough, put a can of compressed air and blow it.
put some paper under the printhead to catch ink.

Try removing the ink cartridges and the printhead. Take the printhead over to a sink without the ink cartridges in it run the printhead under hot water on both sides. insert the ink cartridges and let the outside of the printhead dry for a little bit and then put it back in the printer and try printing. You might need to run a couple Cleaning cycles on it to get the ink reflowing.

Best of luck...
Have a Happy and Safe Holiday Season...

The printheads go bad on these, when several cleanings don't help, you need a new printhead. the price is more than a new machine since they sell the new mfc490 for about $120.00 and the printhead alone to repair yours is $179.00 from Brother...

You need a new printhead, QY6-0063-000. The instructions are packed with the new printhead.

Turn off the device after removing the printhead After removing the printhead, turn off the device, wait about 20 seconds, and turn it on again without the printhead installed. After it has restarted, reinsert the printhead.

it will go through this long routine of perhaps 20 min or so. after its compleate it should print great.

Here are the things you will be asked to try if you call support. They may fix the problems as well. Taking the printhead out and putting it back in is the big helper.

Remove the black and color ink cartridges.
Right above where the black ink cartridge was, in the top left hand corner of the printhead, push up towards the ceiling and you should be able to push a button that releases the printhead.
Place the printhead right back into the printer and push straight back on the back wall.
You should hear a loud snap.
Replace the ink cartridges which should snap as well.
Close the printer.
After about a minute or so the printer will ask you to do a calibration.
Insert a paper and press start.
Scan the calibration sheet.
After that, in the menu, do a printhead clean.
(If this is a 5100, do it in the home center ->? in the top right ->Maintainence ->Clean Printhead.)
Do one basic and one deep.
Print a demo sheet to see if anything has changed.
If the picture looks better, continue to do cleans.
In the event that it does not, the printhead will need to be replaced and since the printer is still under warranty, Kodak specialists will try to overnight you a printhead.
The whole process is short and free.
The number for Kodak AiO Support is 1 800 421 6699.

Yes, this printer has fixed printheads and must have ink in each color to prevent damage to the printheads. Even when printing black only each color is spit in the servicing area to keep the printhead unclogged.

Regards,
Bob Headrick, Microsoft MVP Printing/Imaging

Since it sounds like you've gone through all the steps to clean the print head, I would suggest trying a new black cartridge. There may be a problem with the one you have.