C3765dnf printing grey instead of black

Hello, I have a c3765dnf that randomly started printing gray instead of black. Things I have done: Made sure that the print settings on the PCs were set to color and toner saver/gray scale has been turned off. Replaced the black toner cartridge. Replaced the waste toner cartridge. Cleaned the printer with canned air. Reset the settings on the printer. Any help or ideas would be appreciated.