Patent attributes
A vending machine capable of refilling used ink cartridges as well as dispensing filled ink cartridges is closed. The vending machine includes at least one cartridge receptacle for receiving an ink cartridge, a user interface, a display unit, a nozzle health check module, a printhead servicing module, an ink reservoir, an ink refilling unit, a compartment containing new ink cartridges, a compartment containing filled, second-hand ink cartridges, and a recycle compartment for receiving discarded ink cartridges. The user is presented by the display unit with the option of (a) refilling a used cartridge, (b) purchasing a filled cartridge, or (c) returning a used cartridge in exchange for a purchase rebate or a discount voucher. When the user selects the option of refilling, the vending machine executes a refilling subroutine which includes checking the nozzle health.