Part Names and Functions > Inside Inside 21 A Toner cart ridge cover (D) Open when replacing toner cartridges. B Lock lever Pull up to lock the toner cartridge. C Toner cart ridge Contains the toner for printing. A Lever (A) Pull up to open the front cover when replacing the photoconductor unit or removing jammed paper inside the printer. B Front cove r (A) Open when replacing consumables or removing jammed paper inside the printer. C Fuser unit Fixes the toner to the paper. D Transfer u nit Transfers toner from the drum to the paper.