Hey There, I am Sofia Carter. There are a few potential causes of an HP printer not printing black ink. It could be a result of a clogged or dried out print head, low or empty ink cartridges, or incorrect printer settings. It is also possible that the printer driver is not installed or is outdated. To troubleshoot the issue, try cleaning the print head with a damp cloth, replacing the ink cartridges, and checking the printer settings to ensure they are correct. Additionally, make sure that the printer driver is installed correctly and up to date.