An electrostatic drive includes a first electrode and a second electrode responsive to a drive signal. A bulkhead is adapted to be mounted on the fan cowl having a shaped surface defining an upstream wall. A plurality of traces are formed by milling on the face. In a particular embodiment the bed of the body of water has a first depth over a first area of the bed and a second depth greater than the first depth over a second area of the bed. The controller controls, when the operation hysteresis value stored in the memory medium reaches a preset threshold, the temperature of the fixing device so as to be lower than that before the operation hysteresis value reaches the preset threshold.