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Improved Conductive Path for Electrothermal Ribbon

IP.com Disclosure Number: IPCOM000049430D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Wilbur, CV: AUTHOR

Abstract

An electrothermal printer having a ribbon with greatly reduced return path resistance is shown and described.

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Improved Conductive Path for Electrothermal Ribbon

An electrothermal printer having a ribbon with greatly reduced return path resistance is shown and described.

In the standard configuration, the ribbon comprises a resistive layer 10, an aluminum conductive layer 12 and an ink layer 14. In addition, a layer 16 of Al(2)O(3) is formed between the aluminum conductive layer 12 and the resistive layer 10.

The current path is from print electrode 18, through the resistive layer, through the adjacent area of the Al(2)O(3) layer 16 to aluminum layer 12, along the aluminum layer 12, and back through the Al(2)O(3) layer 16 to return ground electrode 20.

The Al(2)O(3) layer produces a high impedance which has been found to be beneficial since the high impedance causes heating at the most desirable place with the ribbon. However, the Al(2)O(3) layer produces an unwanted impedance in the return current path. If this return path impedance is of a significant level, more costly constant current drivers are required. However, if the return path impedance can be reduced to a sufficiently low level, constant voltage drivers can be used so that the cost and complexity of the electronic drive circuits are greatly reduced.

An improved ribbon which significantly reduces the return path resistance and at the same time retains the aluminum oxide layer in the print electrode circuit utilizes a composite conductive layer. This composite conductive layer comprises an aluminum layer which e...