For the following:
HP CB400A Black Toner cartridge 7.5K page yield at 5% coverage
HP CB401A Blue Toner cartridge 7.5K page yield at 5% coverage
HP CB402A Yellow Toner cartridge 7.5K page yield at 5% coverage
HP CB403A Red Toner cartridge 7.5K page yield at 5% coverage
HP Colour LaserJet CP4005dn CP4005n Laser Printer

Your Toner cartridge will shut down at every cycle of 7.5K printed pages, leaving you unable to print, even though there may be plenty of toner left in the cartridge.
Slash printing costs by simply replacing the chips which shut the cartridges down, to extend Toner cartridge life by up to 30-40%, or use the chip if you are refilling the cartridges, to get them working again.
Each chip lasts for one cycle of 7.5K printed pages, after which it must be replaced.