My Canon MP830 suddenly refuses to print black. The tanks are apparently full or nearly so, and I have used deep cleaning utility several times to no avail. It refuses to print at all. This happened all at once.

Hy, your printhead has dry ink inside. Try to put the print head in ditiled water ( NOT tap water) and live it over night. If that dosent help try in warm distiled water and live it over night. Be careful not to put the print head in the printer when is wet...let it dry for 2-3 hours. If still dosent work you need to replace the printhead.

I service this unit a lot for print quality issues, and most of them come from using non-Canon brand ink. There is a solvent quality to the Canon ink that helps keep the printhead from clogging.
If you are not using it, I recommend it, especially for the big #5 ink tank.
Alignment has nothing to do with the missing print.
Use the cleaning utility in the maintenance area of the printer driver utilities to clean the printhead.
Run the nozzle check, and you should see improvement with each cleaning. Do not run the cleaning more than maybe 5 times, and never use the deep cleaning, you are just wasting a lot of ink.
If you don't see any improvement, stop cleaning and take the unit in for service - we have sonic washers and other effective methods for cleaning and flushing the printheads without damage.
You can replace the printhead yourself, but it will cost less to have it cleaned.

if its been sat for a year it will need new cartridges. ink drys out over time when empty it drys to the head as there is nothing to keep it wet.

canon website they can help ,,may need to download new drivers

the m/c needs the 5 tank for faxes!Is it a canon cart?The head might be blocked!Go to your printer properties and under maintanace do a deep clean!!Good luck!!

get the print head cleaned at ur local ink replacer store

You need to continually clean and deep clean and realign the black until the results are acceptable. Try manual alignment if the auto does not work. Also clean around the exit hole of the black ink cartidge with a cotton bud and isoproyl alcohol.

You will need a new printhead, QY6-0061-000, runs around $60.00 well worth it for your machine.

Doesn't matter if the ink tanks are full. They may also have dry ink on headers. You could try to draw a black rectangle in MS Paintor any other software and try to print it at the best quality. You also could try to remove the black cartridge and see if it leave a ink stain on a absorbant paper (like a napkin). If does not leave a ink stain it means that the ink is dry.

If this is the case you may try to boil some water. When the water is boiled take it away from the fire and sink the cartridge into the boiled water and keep it there until the water cool down.

I have the same promblem, after changing th print head.
It priints black if I change the paper to photo paper.