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Reduction of Contact Resistance in Printing

IP.com Disclosure Number: IPCOM000061272D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Aviram, A: AUTHOR [+3]

Abstract

In resistive ribbon printing, a printhead consisting of an array of 40 electrodes slides upon an electrically conducting ribbon and causes local heating of the ribbon by locally injecting current (arrows 3) into the ribbon. The heating causes regions of an ink layer 4 coated upon the ribbon to melt and to be transferred to a contacting sheet of paper or other material. This method of thermal printing provides fast, high quality printing on a variety of contacting sheets. In general, a contact resistance exists between the sliding electrodes and the resistive ribbon, due to imperfect mechanical contact between these members. Some proportion of the power supplied to the ribbon is dissipated in this contact heating, resulting in heating of the printhead with undesired wear and other consequences and inefficient use of energy.

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Reduction of Contact Resistance in Printing

In resistive ribbon printing, a printhead consisting of an array of 40 electrodes slides upon an electrically conducting ribbon and causes local heating of the ribbon by locally injecting current (arrows 3) into the ribbon. The heating causes regions of an ink layer 4 coated upon the ribbon to melt and to be transferred to a contacting sheet of paper or other material. This method of thermal printing provides fast, high quality printing on a variety of contacting sheets. In general, a contact resistance exists between the sliding electrodes and the resistive ribbon, due to imperfect mechanical contact between these members. Some proportion of the power supplied to the ribbon is dissipated in this contact heating, resulting in heating of the printhead with undesired wear and other consequences and inefficient use of energy. Contact resistance may be reduced by coating the top surface with a highly conductive material, but this is unsatisfactory for printing due to spreading of current from the electrodes with loss in print resolution. To solve this, a surface coating 5 is used having a specific balance of properties that allows quality printing to be maintained. In order to lower contact resistance the coating layer must have a resistivity (ohm-cm) lower than that of the resistive ribbon, i.e, w coating << w ribbon This reduces the contact resistance between each printing electrode 1,2,3.......40 and the resistive medium...