Electrolytic printing head

An improved electrolytic printing head having nonconsumable styli, for use in electrolytic printers of the type in which a record medium is drawn across a plurality of electrically conductive printing styli and an electrical potential is applied to selected ones of the styli to cause current to flow through and produce a mark on selected portions of the record medium, said printing head comprising:

• a first lamina of electrically insulating corrosion resistant glass, said first lamina having an edge surface for contacting a record medium during use of said printing head;
• a plurality of elongated electrically conductive printing styli each of which is fabricated of a mixture of ruthenium dioxide and corrosion resistant glass, said styli being supported at one side of said first lamina between a plurality of elongated grooves that are disposed in spaced parallel relation to one another and extend into said first lamina, said elongated printing styli terminating at and forming continuations of said edge surface for contacting a record medium during use of said printing head;
• and
• a second lamina of electrically conductive material supported on the other side of said first lamina, said second lamina terminating at and forming a continuation of said edge surface for contacting a record medium during use of said printing head, said second lamina being fabricated of a mixture of ruthenium dioxide and corrosion resistant glass and being operative to function as a reference electrode when an electrical potential is applied between selected ones of said printing styli and said second lamina;
• surface portions of said styli and of said second lamina remote from said edge surface being exposed to permit electrical connections to be made to said styli and to said reference electrode, and conductor means carried by and confined in extent to said exposed surface portions for making said electrical connections.