Abstract: An ink jet printing system including a lower cabinet in which is supported ink and solvent supplies, an upper cabinet in which is supported a microprocessor based controller and a remote ink jet printing head connected with the lower cabinet through a flexible cable which supplies ink, solvent and electrical control signals to the head. A proximity sensor may be mounted on the head to supply sense signals to the controller. A nozzle assembly including critically dimensioned, linearly arranged ink jet orifices is mounted in a predetermined relationship with a U-shaped pattern of control valves to allow the supply passageways linking the control valves and orifices to be substantially identical in shape and ink flow characteristics. Ink reservoirs adjacent each ink jet orifice combine with the uniform supply passageways to provide highly controllable ink jet discharge droplets dependent upon the opening time of each control valve.