If your Brother printer not printing black or Help 1-877-331-5006 despite having a full ink cartridge, it could be due to several reasons. First, check if the ink cartridge is installed correctly and securely. Sometimes, the printer may not recognize a new or full cartridge if it’s not seated properly. Next, clean the print head using your printer's maintenance menu to remove any clogs or dried ink. Ensure the black ink is not dried or clogged, especially if the printer hasn’t been used in a while. You can also try running a nozzle check or performing a deep cleaning cycle.