A control apparatus calculates the capacitor maximum power that can be supplied to a capacitor depending on the detected value of the temperature of the capacitor, and calculates the output power of the fuel cell, the real power of the motor that actually powers the drive motor, and the load power that actually powers an electrical load, excluding the drive motor. Each heater element 10 is configured to heat a bubble forming liquid 11 in the printhead to a temperature above its boiling point to form a gas bubble 12 therein. The motor controller controls the motor to provide consistent speed independent of load weight or incline, and further provides regenerative braking. wherein at least a part of said mammal’s immune system is stimulated non-discriminatingly, reacts hypersensitively to said immunogen, or fails to react to said stimuli.