My cannon i550 printer will not print black. I have deep cleaned several times. The cartridge is 3/4 full. Any suggestions or ideas would be greatly appreciated. Everything else works fine.

Thanks for any help,

Chey

The print head may be clogged.
See if soaking it in a hot water bath for 30 minutes, and then running it under hot water for at least 10-15 minutes helps.
If not, then you may have to either replace the print head, or get a new printer.