The present disclosure discloses a method implemented by a printer to control a fluid firing unit of a printhead, when said printhead is coupled to the printer, to operate according to any one of a normal printing mode and a recovery mode. According to the method, if the fluid firing unit is operated according to the normal printing mode, a first voltage is applied to the fluid firing unit to fire the fluid firing unit during a printing operation; and if the fluid firing unit is operated according to the recovery mode, a second voltage higher than the first voltage is applied to the fluid firing unit to clean the fluid firing unit.