A mobile communications device includes a controller, a connector device configured to couple with a computer system, an interface device, and memory. The first beam is arranged to overlap the image forming unit at a longitudinal central part thereof, when projected along the axial direction, while longitudinal ends of the first beam are arranged on outer sides of the image forming unit. The soft charge unit is coupled to the loudspeaker through an output terminal and supplies a driving current according to a first control signal to soft charge the loudspeaker, so as to gradually increase a voltage level on the output terminal. A high area density of drop generators and relatively low droplet volume of water-based ink provides high print resolutions and energy efficient operation. Charges are then stored into the charge storage media layer of the charge storage apparatus through the electric field and the charge patterns are then formed. Other embodiments are described and claimed.