Security for images formed by impact based systems
First Claim
1. A pressure-sensitive image-transfer sheet, comprising:
- a sheet having a coating of microcapsules on one side thereof, the microcapsules containing a solvent with high degree of paper penetrating capability and a detectable agent therein and rupturable in response to pressure applied from the other side of the sheet to release the solvent and the detectable agent in an image area defined by the pressure-ruptured microcapsules, the penetrating capability of the solvent sufficient to penetrate through an image acceptor sheet in contact with the one side of said sheet to form a confirming image on the opposite side of the acceptor sheet.
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Accused Products
Abstract
A document system having improved image security for preventing or reducing the likelihood of successful alteration of information printed on a document includes a detectable substance is released from ruptured microcapsules onto the document in image areas. The substance that penetrates through the document to form a confirming image on the reverse surface. Another detectable substance of lesser penetrating ability simultaneously may be released onto the document in the image areas. Spreading of the first substance outside the boundaries of the image area created by the second substance may produce a halo effect around the image area. Documents as treated by the methods are disclosed, as well as articles comprising a document to be treated in contact with a sheet coated with the detectable substance. The first substance is microencapsulated, the second substance may or may not be microencapsulated.
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Citations
22 Claims
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1. A pressure-sensitive image-transfer sheet, comprising:
a sheet having a coating of microcapsules on one side thereof, the microcapsules containing a solvent with high degree of paper penetrating capability and a detectable agent therein and rupturable in response to pressure applied from the other side of the sheet to release the solvent and the detectable agent in an image area defined by the pressure-ruptured microcapsules, the penetrating capability of the solvent sufficient to penetrate through an image acceptor sheet in contact with the one side of said sheet to form a confirming image on the opposite side of the acceptor sheet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A pressure-sensitive image forming system, comprising:
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a transfer sheet having a coating of microcapsules on one side thereof, the microcapsules containing a solvent with high degree of paper penetrating capability and a detectable agent therein and rupturable in response to pressure applied from the other side of the transfer sheet to release the solvent and the detectable agent in an image area defined by the pressure-ruptured microcapsules; and an acceptor sheet underlying said transfer sheet for accepting the solvent and the detectable agent from the ruptured microcapsules, the penetrating capability of the solvent sufficient to penetrate through the acceptor sheet to form a confirming image on the opposite side thereof. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification