A fluid ejection system includes a first fluid ejection head comprising a first nozzle plate that includes a first set of fluid ejection nozzles capable of ejecting first fluid drops and a second fluid ejection head comprising a second nozzle plate that includes a second set of fluid ejection nozzles capable of ejecting second fluid drops. One end of the resilient member is fixed to the first fixing member, and the other end of the resilient member resists the electrical conductive member with the insulated protector toward the battery so that the electrical conductive member is electrically connected to an electrode of the battery. The deposition parameters for depositing the thin transition-metal based scattering layer are adjusted to provide the scattering layer uniformly over all substrates within the lot.