A printhead chip for an inkjet printhead includes a plurality of nozzle arrangements on a substrate (12). Each nozzle arrangement (10) includes nozzle chamber walls (18) and a roof (20) that define a nozzle chamber (22) with the roof defining an ink ejection port (30) in fluid communication with the nozzle chamber. An ink-ejecting member or paddle (54) is positioned in the nozzle chamber and displaceable towards and away from the ink ejection port so that a resultant fluctuation in ink pressure within the nozzle chamber results in an ejection of ink from the ink ejection port (30). At least one work transmitting structure of a lever mechanism (38) is displaceable with respect to the substrate results in displacement of the ink-ejecting member. A thermal bend actuator (62) is capable of displacing the structure upon receipt of an electrical drive signal (14). An air chamber (80) defined by walls (90) and a covering formation (78) are positioned over the actuator to protect the component from ingress of microscopic detritus such as paper dust.