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Diazo Printer

IP.com Disclosure Number: IPCOM000078962D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Battison, AH: AUTHOR [+3]

Abstract

Printing has been done on a diazo paper, using a 2 per cent ammonium hydroxide solution in a matrix printer, using an on-demand or oil can type of ink-jet nozzle having a drop rate of 1800 Hz, and a character rate on the order of 30 characters per second. Ultraviolet light is used to bleach out the diazonium compound which is not activated by the solution. Therefore, on a blue diazo, blue matrix dots are produced, green spots on green diazo, etc. The printing is readable from the moment of drop impact, and becomes subsequently of maximum attainable density, for a given paper, as the droplet retains optimum PH until dye coupling is completed. The paper bleaches out to a white background rapidly upon exposure to ultraviolet light, or more slowly on continued exposure to room light containing ultraviolet light.

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Diazo Printer

Printing has been done on a diazo paper, using a 2 per cent ammonium hydroxide solution in a matrix printer, using an on-demand or oil can type of ink- jet nozzle having a drop rate of 1800 Hz, and a character rate on the order of 30 characters per second. Ultraviolet light is used to bleach out the diazonium compound which is not activated by the solution. Therefore, on a blue diazo, blue matrix dots are produced, green spots on green diazo, etc. The printing is readable from the moment of drop impact, and becomes subsequently of maximum attainable density, for a given paper, as the droplet retains optimum PH until dye coupling is completed. The paper bleaches out to a white background rapidly upon exposure to ultraviolet light, or more slowly on continued exposure to room light containing ultraviolet light.

A solution of 55cc of 190 proof C(2)H(5)OH, 12cc distilled water and 33cc of 30 % (concentrated) NH(4)OH, saturated with ammonium carbonate (NH(4))(2)CO(3) . H(2)O has been used. Ammonium carbonate, NH(4)CO(2)NH(2) has also been successfully used. Multiple color printing can be obtained, by using single sheet multiple diazo coatings or different diazo papers.

An alcohol-water-base ink can also be used in regular ink-jet printing. The negative volume mixture provided improved performance by minimizing entrapped air.

A typical ink formulation comprises 400 mg methyl violet incorporated into 250cc of a 53% ethyl alcohol - 47% distilled water mixtu...