Controlling a multi-wire printhead
AssigneeInternational Business Machines Corporation
InventorsLouis V. Galetto, James M. Rakes
Life of this patent
Estimating the term…
Abstract
A current shunt multiplexed driver circuit in a high resolution multi-wire printhead is provided for use in an electroerosion printer. The circuit can reduce to the number of active devices required per print wire to two times the square root of the number of wires.
Claims10
Circuit apparatus for selectively energizing individual wires in an electroerosion printhead for forming marks on grounded metal coated paper including a plurality of wires adjacent the metal coated paper and arranged in M groups having an equal number N wires comprising:
- M selector transistors for selecting a group M of wires;
- N transistor switches for selecting individual wires in a group M;
- means for generating a first current from ground through the metal coated paper and each non-selected wire into a negative potential source to make a mark;
- and
- means for generating a second current from a positive potential source and bypassing the metal coated paper wire junction to avoid making a mark.
An improved method for controlling the firing of individual wires in a multi-wire print head to make marks on metal coated paper comprising the steps of:
- generating a first current from ground through the metal coated paper, a wire and a source of negative potential to make a mark;
- and
- generating a second current bypassing the wire metal coated paper boundary from a source of positive potential into a source of negative potential to avoid making a mark.
A control circuit responsive to symbol generating means for a multi-wire printhead in contact with metal coated paper comprising:
- means for maintaining the paper at ground potential;
- a source of positive potential;
- first selectively operable means connecting said source of positive potential to each wire in said printhead;
- a source of negative potential;
- second selectively operable means connecting said source of negative potential to each wire in said printhead;
- means for generating a first current from the paper through a print wire into the negative potential said current being sufficient to vaporize the metal coating on the paper;
- and
- means for generating a second current from said positive potential to said negative potential, said current bypassing the print wire paper junction.
Dependencies are inferred from the claim text.