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Base Layer Formulation for Direct Negative-Direct Master in Multi-Styli Print Heads

IP.com Disclosure Number: IPCOM000036434D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 10K

Publishing Venue

IBM

Related People

Afzali-Ardakani, A: AUTHOR [+3]

Abstract

A technique is described whereby the base layer formulation, of direct negative-direct master fabrication in multi-styli printer heads, such as used in the IBM 4250, is improved by a slight modification of their chemical constituents.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

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Base Layer Formulation for Direct Negative-Direct Master in Multi-Styli Print Heads

A technique is described whereby the base layer formulation, of direct negative-direct master fabrication in multi-styli printer heads, such as used in the IBM 4250, is improved by a slight modification of their chemical constituents.

Direct negative-direct plate (DN/DP) master plates, as used in multi-styli printer heads, display gouges in the material, from 20 microns wide and from 0.5 to 100 mm or more in length, when subjected to the prior-art method of fabrication. The presence of these gouges was considered unacceptable for direct negative and direct master base layer formulation. Also, a post-annealing process to coat the base samples at moderately high temperatures for a significant length of time was used. Under these conditions, the polyester substrate on which the base layer is coated would distort severely. This distortion of the substrate created serious problems when separate color offset masters are required because of the difficulty in securing color registration. The concept described herein provides improvements to the fabrication process so as to eliminate gouging and distortions.

Analysis of the prior-art fabrication process revealed that the primary cause of gouging was due to lack of adhesion of the base layer composite to the polyester substrate and the cohesion of pigments in the crosslinked binder used in the fabrication. Improving the adhesion of the base layer to the polyester substrate, through the use of a pretreated adhesive layer at a prescribed postcure temperature, decreased the number of gouges significantly. However, the number of gouges which remained were still unacceptable, and the cure temperature was not considered practical. It was concluded that the composite polyurethane of the base layer was too brittle, such that the pigments subjected to high to moderate forces, exerted from the styli, would separate from the brittle film and produce the gouge.

Proving that the brittleness of the base layer is one reason for gouging, a polyurethane binder which inherently has very high flexibility, was used and pigmented with silica at the same loading as performed in the prior-art fabrication process. The gouge test on the finished sample resulted in no o...