Electric field paper stabilizing system for an electrographic plotter, printer or the like

An electric field paper stabilizing system for an electrographic plotter, printer or the like incorporating a continuous transport belt means for stabilizing a recording medium supported thereon in invariant registration during one or more revolutions with respect to a writing head comprising:

• a recording medium having a writing surface and an opposed conductive surface;
• a transport belt having a conductive surface for supporting said recording medium;
• a dielectric material interposed between said supporting surface of said transport belt and said conductive recording medium for insulating said recording medium from said transport means;
• planar electrode means provided in said dielectric layer and said electrode means having a planar surface integral with the surface of said dielectric layer adjacent said recording medium for coating said recording medium at ground potential;
• means for applying a differential potential between said transport belt and said electrode means such that a strong electric field is established between said recording medium and said transport belt and the coulomb force exerted on said recording medium by said electric field adheres said recording medium to said transport means in a substantially invariant position.

An electric field hold down system for precise registration of paper or other recording medium to a transport belt having a conductive paper supporting surface in a multipass plotter, printer or the like comprising:

• a recording medium having a writing surface and an opposed conductive surface;
• a writing head means for applying an electric charge to said writing surface of said recording medium;
• a dielectric material provided on said paper supporting surface of said transport belt;
• grounding means provided integrally in said dielectric material for holding said conductive surface of said recording medium uniformly at ground potential and for preventing interference with the applied electric fields on said writing surface;
• and
• means for applying a differential potential between said recording medium conductive surface and said paper supporting surface of said transport belt such that said recording medium conductive surface and said paper supporting surface said transport belt act as parallel conductive plates of a capacitor having a maximized capacitance.

A method for providing an electric field hold down force for invariantly stabilizing paper or other recording medium on a transport belt having a conductive paper supporting surface with respect to a writing head in a plotter, printer or the like comprising the steps of:

• providing a thin layer of dielectric material on the conducting surface of said transport belt;
• providing a thin planar electrode means in said surface of said dielectric layer such that the planar surface of said electrode means is flush with said surface of said dielectric layer;
• using said electrode means to hold said recording medium at ground potential;
• applying a differential potential between said electrode means and said conductive surface of said transport belt such that a strong electric field is developed between said transport belt and said recording medium such that the coulomb force exerted on said recording medium by said electric field rigidly and invariantly adheres said recording medium to said belt.

An apparatus for providing a maximized electric hold down force between a transport belt and a recording medium supported thereon for multiple passes past an electrostatic writing head comprising:

• a transport belt having a conductive surface;
• a dielectric coating provided coextensively on the surface of said transport belt, characterized by high permittivity and minimal thickness;
• a planar grounding means provided in the surface of said dielectric coating for holding said contacting surface of said recording medium at ground potential and for preventing interference with the electric fields from said writing head on said writing surface;
• means for applying a differential potential between said belt and said recording medium such that said belt and said recording medium act as parallel conductive plates of a capacitor and said recording medium is invariantly stabilized on said dielectric coating.