Browse Prior Art Database

Carbon Coating Formulation With Security Feature

IP.com Disclosure Number: IPCOM000079625D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Godlewski, RB: AUTHOR [+2]

Abstract

This modified carbon coating formulation facilitates detection of alteration of carbon images.

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Carbon Coating Formulation With Security Feature

This modified carbon coating formulation facilitates detection of alteration of carbon images.

Conventional carbon coating formulations provide carbon images that can readily be altered, by "lifting" one or two characters (e.g., a digit from a serial number) from a substrate and replacing it with another by techniques that are difficult to detect. To deter this, a conventional carbon coating formulation is modified to include a small amount of fluorescing and/or phosphorescing dyes or pigments. The concentrations are sufficiently small to preclude chromatic shifts in the appearance of the carbon image, to preserve the integrity of black images on a white or substantially white background.

When a data processible card, sheet or the like is imaged by pressure applied from the uncoated side of the carbon paper, the imprinted image will appear black and clearly legible in normal white light. However, when exposed to actinic radiation (black light, 2500-3500 Angstroms), the carbon image will appear in a color, dependent upon the particular fluorescent/phosphorescent dye or pigment used. Thus, if the visible imprinted image is removed mechanically from the substrate, the fluorescent/ phosphorescent residue of the original image will remain and be clearly legible under black light, thus facilitating detection of forgeries.

A carbon coating formulation modified as above-described may comprise, in parts by weight: Ingredien...