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Wear Resistant Thermal Printing Head

IP.com Disclosure Number: IPCOM000034252D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Joshi, RV: AUTHOR [+4]

Abstract

A technique is described whereby a thermal printing head is fabricated with a hard diamond-like carbon material to enhance its wearability characteristics. The concept is an improvement over previous techniques in that it significantly extends the life of the thermal print head. Typically, thermal print heads are fabricated with a thin layer of material, such as tungsten, to form the thermal print electrodes, as shown in Fig. 1. (Details of the film assembly are shown in Fig. 2.) In producing the thin layer of tungsten, a thick tungsten sheet is wet etched to form the print electrodes. A resistive ribbon is used in conjunction with the print head to perform the thermal print transfer operation. The resistive layer is generally made from polycarbonate 17 microns thick.

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Wear Resistant Thermal Printing Head

A technique is described whereby a thermal printing head is fabricated with a hard diamond-like carbon material to enhance its wearability characteristics. The concept is an improvement over previous techniques in that it significantly extends the life of the thermal print head. Typically, thermal print heads are fabricated with a thin layer of material, such as tungsten, to form the thermal print electrodes, as shown in Fig. 1. (Details of the film assembly are shown in Fig. 2.) In producing the thin layer of tungsten, a thick tungsten sheet is wet etched to form the print electrodes. A resistive ribbon is used in conjunction with the print head to perform the thermal print transfer operation. The resistive layer is generally made from polycarbonate 17 microns thick. Aluminum film is deposited on one side of the poly- carbonate, approximately 1000 angstoms thick. The ink film, 3 microns thick, is mounted on the aluminum film. In the operation, current of 25 to 30 ma is passed from the electrode tip to the resistive layer, and then to the aluminum film, which acts as a ground return. A native oxide is formed on the aluminum between the polycarbonate. The aluminum film acts as a heater element to soften the ink to provide the print transfer from the ribbon to the paper. The ribbon assembly moves continuously such that the electrode contact to the film may be intermittent. This intermittent contact causes the tungsten electrode to...