Heat sensitive system and use thereof
AssigneeWallace Computer Services, Inc.
InventorJohn C. H. Chang
Life of this patent
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Abstract
A heat sensitive system comprises a document having a localized, non-pressure sensitive, coating of chromogenic composition activated at moderate temperatures. Quickly striking the chromogenic composition with a fingernail or blunt object produces a colored image by frictional heat. The chromogenic composition contains a chromogenic compound and a color developer which are non-pressure sensitive and non-reactive at room temperature. The chromogenic composition can be an intimate mixture of the chromogenic compound and the developer or alternatively separate layers of each of the components.
Claims39
A method of verifying the authenticity of a document, said document comprising a support bearing an information area and a verification area, said information area comprising a visible principal image;
- said verification area comprising a localized coating of a heat activatable chromogenic composition capable of forming a visible colored image, said method comprising
- applying frictional heat to said localized coating of said heat activatable chromogenic composition to form a visible colored image.
A negotiable instrument comprising a support bearing an information area including a visible principal image and an authentication area for verifying the authenticity of said document, said authentication area comprising
- a localized coating of a frictional heat activatable chromogenic composition for producing a visible colored image by application of frictional heat;
- said chromogenic composition comprising a solid chromogenic compound and solid color developing material.
A document comprising a support having a surface bearing an information area including a visible principal image, and at least one authentication area for verifying the authenticity of said document, said authentication area comprising a localized, substantially colorless coating of a heat activatable non-pressure sensitive chromogenic composition, said chromogenic composition comprising:
- a solid chromogenic material and a solid color developing material having a melting or softening point of about 40.degree. C. to about 140.degree. C., said solid chromogenic material and said solid color developing material being in physical contact prior to reaction;
- such that heat applied to said authentication area causes said chromogenic material to chemically react with said developer material to produce a visible colored image at temperatures above room temperature;
- said information area being free of chromogenic compounds, and free of color developers capable of reacting with chromogenic compounds to produce a visible image by application of heat.
A document which comprises:
- a support having at least one surface bearing an information area and a localized verification area;
- said information area having a visible principal image;
- and
- said localized verification area comprising a localized, substantially colorless coating of a heat activatable chromogenic composition, said heat activatable chromogenic composition comprising a chromogenic compound and a color developer, said chromogenic compound and said color developer substantially colorless solids in physical contact prior to reaction, but which can chemically react to produce a visible colored image by application of heat at temperatures above room temperature;
- said information area being free of chromogenic compounds, and free of color developers capable of reacting with chromogenic compounds to produce a visible image by application of heat.
Dependencies are inferred from the claim text.