The HP 771 DesignJet Maintenance Cartridge (CH644A) is a service consumable for the printer’s ink system. It supports routine printhead care as part of the printer’s maintenance process.
The cartridge is used to clean and maintain the printheads. It also seals the printheads when they are not in use, helping prevent them from drying out. The printer monitors its status and displays alerts as it approaches capacity and when it needs replacement.
This is the maintenance cartridge specified for the HP 771 ink system. Its part number is CH644A.