Electroresistive printing apparatus

Claim 1

Electroresistive writing apparatus for writing with thermally transferable ink on a receiving surface in response to selective application of localized electric current comprising: a layer of thermally transferable ink adjacent said receiving surface, a base layer carrying said ink layer, a thin, burnable opaque layer of conductive material on said base layer opposite said ink layer for conducting localized electric current to heat said ink for transfer to said receiving surface and to burn away said opaque conductive layer from said base in response to said localized application of electric current thereto, a plurality of conductive electrodes having an abrasion resistance less than that of said conductive material, means having an abrasion resistance less than or equal to said electrodes for holding said electrodes in an insulated fixed relationship with respect to each other, means for controllably transporting said electrodes relative to said conductive medium at a predetermined contact pressure, and means for selectively applying predetermined electric currents to said electrodes, said currents burning away said conductive layer adjacent an electrode and causing less electrode erosion than the erosion caused by physical wear.

Claim 4

A system for electroresistive writing on a conductive medium comprising: a conductive grounding member for contacting said conductive medium along substantially the entire width of the writing area, a conductive carriage track electrically connected to said grounding member, head assembly means translatably mounted on said carriage track including means for electrically contacting said carriage track to provide a movable ground contact, writing electrodes for contacting said conductive medium adjacent said grounding member, and means connected to said movable ground contact and said writing electrodes for selectively applying an electric current through said writing electrodes, said conductive medium and said ground contact, whereby the resulting path of said electric current is small thereby limiting the generation of spurious electromagnetic radiation.

Claim 5

A system for electroresistive writing on a conductive medium comprising: a conductive grounding member for contacting said conductive medium along substantially the entire width of the writing area, a conductive carriage track electrically connected to said grounding member, head assembly means translatably mounted on said carriage track including means for electrically contacting said carriage track to provide a movable ground contact, writing electrodes for contacting said conductive medium adjacent said grounding member, and means connected to said movable ground contact and said writing electrodes for selectively applying an electric current through said writing electrodes, said conductive medium and said ground contact, whereby the resulting path of said electric current is small thereby limiting the generation of spurious electromagnetic radiation.