Selectable density charge deposition printing system

Ionographic raster scan printing apparatus capable of printing with selectable print density utilizes an imaging drum having a surface movable in a process direction, a connector assembly for receiving an imaging module having a characteristic dot density determined by a set of control electrodes individually driven by clocked driver elements, a sensor module for generating density signals representative of the characteristic dot density, and a position encoder for generating position signals representative of the instantaneous position of the imaging drum surface. A scan clock synthesizer module generates activation signals for clocking the driver elements, the signals having a clock frequency proportional to an algebraic combination of the density signals and the position signals.