Method to charge toner for electrophotography using carbon nanotubes or other nanostructures

A system to impart n electrostatic charge to particles comprising:

• a plurality of nanostructures disposed over a first electrode array, wherein the first electrode array comprises a plurality of three or more electrodes spaced apart, the first electrode array having a first end and a second end, the second end being closer to a receiving surface than the first end, and each electrode comprising a major surface, wherein the major surfaces of the plurality of electrodes are generally coplanar with each other;
• a power source operatively coupled to the first electrode array to supply a multi-phase voltage to the first electrode array and adapted to create a traveling electric field between each electrode of the first electrode array, wherein the traveling electric field is adapted to cause electron emission from the plurality of nanostructures and is further adapted to form a plurality of charged particles;
• a controller configured to control an amount of electrostatic charge imparted to the plurality of particles by adjusting a frequency and/or a magnitude of the traveling electric field between each electrode of the first electrode array;
• and
• a receiving surface in close proximity to the plurality of nanostructures at the second end of the first electrode array, wherein the system is adapted to transport the plurality of charged particles onto the receiving surface from the first end to the second end using the traveling electric field, wherein the traveling electric field imparts a force on the plurality of charged particles in at least one direction from the first end to the second end.