Method and security substrate for protecting against duplication with a color copier

• US 5,338,066 A
• Filed: 04/01/1992
• Issued: 08/16/1994
• Est. Priority Date: 04/01/1992
• Status: Expired due to Term

• Current Assignee: Nocopi Technologies, Inc.
• Original Assignee: Nocopi International Ltd.
• Inventors: Gundjian, Arshavir
• Primary Examiner(s): Sluby, P. C.
• Application Number:
  US07/861,712
• Time in Patent Office: 867 Days
• Field of Search: 428/915, 428/916, 428/207, 428/333, 428/531, 503/201, 283/902, 283/67, 283/95
• US Class Current: 283/67
• CPC Class Codes: G03G 21/043 by using an original which is not reproducible or only reproducible with a different appearence, e.g. originals with a photochromic layer or a colour background
• CPC Class Codes: Y10S 283/902 Anti-photocopy
• CPC Class Codes: Y10S 428/915 Fraud or tamper detecting
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10T 428/24901 including coloring matter
• CPC Class Codes: Y10T 428/261 In terms of molecular thickness or light wave length
• CPC Class Codes: Y10T 428/31967 Phenoplast

Abstract

A method for protecting against duplication of a document with a color copier and a security substrate comprises providing a background color on a document having an average reflectance value and printing on the background with a contrast color having a spectral characteristic which modulates the average reflectance value by no more than 5% and has an average value equal to the average reflectance value. The contrast color is printed with a printing medium including one of a colorformer leucodye and an activating phenolic resin. The other of the colorformer leucodye and the activating phenolic resin is to the printing medium on the document later to verify that the document is an original.

Claims

1. A security substrate for protecting against duplication with a color copier;

comprising;

a main surface;

a background color on the main surface having an average reflectance value; and

a contrast color on the background color having a spectral characteristic which modulates the average reflectance value by no moret han 5% and has an average reflectance equal to the average reflectance value, wherein the contrast color is composed of a printing medium including one from the group consisting of a color former leuco dye and an activating phenolic resin.

2. A method for protecting against duplication with a color copier;

comprising the steps of;

providing a background color on a substrate having an average reflectance value; and

printing on the background color with a contrast color having a spectral characteristic which modulates the average reflectance value by no more than 5% and has an average value equal to the average reflectance value, wherein the step of printing the contrast color comprises printing with a printing medium including one from the group consisting of a color former leuco dye and an activating phenolic resin.