Method for improving the printing quality and repetition accuracy of electrographic printers and a device for accomplishing the method

A device for improving the printing quality and repetition accuracy of an electrographical printer including a toner particle carrier having a toner particle supply located thereon and a backing electrode, the device comprising:

• an electrode matrix including a carrier having a plurality of electrodes and apertures, each aperture being completely surrounded by at least one electrode;
• means for producing an electrical charge pattern by supplying a pattern of electrical signals to the electrodes forming the matrix, the electrical charge pattern being electrostatically arranged to control the transmission of electrical fields through the apertures for controlling flow of toner particles through the electrode matrix onto an information carrier arranged between the particle supply and the backing electrode, said means for producing an electrical charge pattern including:
• means for attracting toner particles through at least one of the apertures by generating a single electrostatic field between the particle carrier and the backing electrode;
• and
• means for preventing toner particles from moving through the apertures by generating electrostatic fields between the backing electrode and the electrode matrix and between the electrode matrix and the particle carrier.

An electrographic printer comprising:

• a toner particle supply;
• a back electrode;
• a control electrode for controlling a flow of toner particles from said toner particle supply to a recording medium located between the toner particle supply and the back electrode;
• and
• a power supply for applying a charge to said back electrode to create a single electrostatic field between the toner particle supply and the back electrode, the single electrostatic field being the only attractive force for attracting the toner particles from the toner particle supply toward the back electrode through the control electrode.