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Coating to Increase Wear Resistance in Impact Belts and Other Print Mechanisms

IP.com Disclosure Number: IPCOM000052435D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Kuntzleman, HC: AUTHOR [+3]

Abstract

A successful impact printing mechanism employs the use of a circular metallic belt having in its outer periphery raised characters or fonts. These fonts are impacted by hammers which impress the characters through a ribbon onto the paper. Various manufacturers produce printers of this kind. A common problem affecting the technology is the substantial mechanical wear (friction against the paper) of the raised characters, especially when the belt is run to print at high rates (over 1000-2000 lines/minute). This is a serious problem because the belt has to be replaced often. The material from which the fonts are made is usually a hard, high wear-resistant steel or similar alloy.

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Coating to Increase Wear Resistance in Impact Belts and Other Print Mechanisms

A successful impact printing mechanism employs the use of a circular metallic belt having in its outer periphery raised characters or fonts. These fonts are impacted by hammers which impress the characters through a ribbon onto the paper. Various manufacturers produce printers of this kind. A common problem affecting the technology is the substantial mechanical wear (friction against the paper) of the raised characters, especially when the belt is run to print at high rates (over 1000-2000 lines/minute). This is a serious problem because the belt has to be replaced often. The material from which the fonts are made is usually a hard, high wear-resistant steel or similar alloy.

A solution to the problem of wear in these and other print mechanisms is proved by protecting the impact printing surfaces, with layers of very hard, high adhesion, high wear-resistant oxide film. The film is a composite of two layers of oxides which are compatible with each other and isomorph in crystal structure, as follows:

The first layer has the function of providing adhesion to the substrate and acting as a link between the substrate and the second layer, the first layer usually being titanium oxide (TiO(2)).

The second layer is formed of ruthenium oxide (RuO(2)), material many times harder than steel and extraordinarily resistant to mechanical thermal and electrical corrosion.

Applications of the protective coatings.

A) Sputtering. An established reliable procedure consists first, in sputtering the substrate with a titanium target in an oxygen atmosphere (reactive titanium sputtering) which activates the substrate surface and covers it with a layer of TiO(2) of about 2000-3000 Angstroms. The second step to switch the target and sputter the TiO(2) covered substrate with a ruthenium target also in oxygen atmosphere (reactive ruthenium sputtering) which covers the substrate with a final layer of RuO(2) with a thickness varying from 1 to 25 Mu (1 mil) depending on the applications. Initial step a) can also be started by evaporating Ti metal onto the surface, followed by sputter cleaning of the same in argon and the rest of the procedure the same as above.

B) Electrolysis. Ruthenium metal can easily be electro-deposited onto a metallic surface and the layer further oxidized to RuO(2) either electrochemically or by oxygen-thermal oxidation. The problem that has to be worked out here is that of the proper conditions to obtain good adhesion.

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