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Generation of Gray Scale in Electrochemically Sensitive Printing Apparatus

IP.com Disclosure Number: IPCOM000046199D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Bernier, WE: AUTHOR [+4]

Abstract

Certain electrochemically sensitive printers employ a recording medium having a leuco-dye (L-Dye) or matrix of such dyes coated thereon together with a concentrated electrolyte solution containing a bromine catalyst. Upon activation of the medium surface with moisture, the surface becomes electrically conductive. When electrical pulses are thereafter supplied for appropriate periods via "write" styli, the leuco-dye is converted to its visible, colored form (V-Dye) in accordance with the following reactions: (Image Omitted)

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Generation of Gray Scale in Electrochemically Sensitive Printing Apparatus

Certain electrochemically sensitive printers employ a recording medium having a leuco-dye (L-Dye) or matrix of such dyes coated thereon together with a concentrated electrolyte solution containing a bromine catalyst. Upon activation of the medium surface with moisture, the surface becomes electrically conductive. When electrical pulses are thereafter supplied for appropriate periods via "write" styli, the leuco-dye is converted to its visible, colored form (V- Dye) in accordance with the following reactions:

(Image Omitted)

Dye conversion occurs in the presence of the write pulses, as shown above by the coupled pair of reactions.

If sufficient or even excessive quantities of the leuco-dye are present in the recording medium, a controlled deposition of electrical charge (coulombs) on its surface will convert a controlled amount of bromide to bromine. This generated bromine will react in a predictable manner to convert a predeterminable quantity of the leuco-dye to yield a printed dot of controlled intensity. Thus, by regulating the quantity of charge delivered to the recording medium at any point thereof, it is possible to manipulate the resultant intensity or shade of the resultant printed dot. This method of gray scale control is essentially continuous and viable from a white or imprinted area to a strongly colored dot, the intensity of which is dependent upon the quantity of leuco-dye present, the extinction coefficien...