Patent ID: 8511228
Filing Date: 2013-08-20
Classification: B41J,B41M,G01K

Abstract:
1. A method of hiding and revealing an authentication print to indicate whether a sheet media item is authentic, the method comprising: printing with ink of a first color the authentication print on a first portion of the sheet media item having a thermally sensitive coating of an initial color which substantially matches the first color of the authentication print to render the first color of the authentication print substantially invisible against the initial color of the thermally sensitive coating and thereby to hide the authentication print; applying heat to a second portion of the sheet media item which is different from the first portion of the sheet media item to provide a message of a second color on the second portion of the sheet media item, wherein the second color of the message on the second portion of the sheet media item is different from the first color of the authentication print on the first portion of the sheet media item; and at the same time heat is being applied to the second portion of the sheet media item, applying heat to the first portion of the sheet media item to change the thermally sensitive coating from the initial color which substantially matches the first color of the authentication print to a different color to render the first color of the authentication print visible against the different color of the thermally sensitive coating and thereby to reveal the authentication print to indicate that the sheet media item is authentic.