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User Applied Etchants for IBM 4250 Prepared Direct Master Enabling Use of Low-Tack Press Inks

IP.com Disclosure Number: IPCOM000035352D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Afzali-Ardakani, A: AUTHOR [+4]

Abstract

Disclosed are etchant solutions which may render the image areas of a direct master, made by the IBM 4250 electro-erosion printer more ink- receptive.

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This is the abbreviated version, containing approximately 93% of the total text.

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User Applied Etchants for IBM 4250 Prepared Direct Master Enabling Use of Low-Tack Press Inks

Disclosed are etchant solutions which may render the image areas of a direct master, made by the IBM 4250 electro-erosion printer more ink- receptive.

It has been observed that such direct masters provide adequate print density when high-tack ink is employed in the offset press. However, with low-tack inks the print density on the paper may become very low and unacceptable. This problem of low print density with low-tack ink was found to originate from the residual aluminum which is left behind in the electro-erosion process. While the residual aluminum does not totally prevent inking of the master in the written region, its presence does in fact decrease the print density. In a series of experiments various etchants were applied to the written area in order to reduce the residual aluminum.

Effective etchants found include dilute (2-5%) phosphoric acid, dilute sodium hydroxide (pH of 11-13) and dilute solutions of sodium carbonate with trisodium phosphate. Several commercially available solutions which are used with conventional offset plates were also found to be effective. Among them are Itek Mega Developer of Itek Graphic System, Rochester, New York, Plate SAV-UR of
R. R. Smith, Indianapolis, Indiana, and Alka-Fount of Anchor/Lithkemko, Orange Park, Florida. These solutions may be applied to the master by swabbing, spraying or dipping or may be automatically applied b...