Printed magnetic ink overt security image

Abstract

A security image and method of forming said image is disclosed wherein a substrate having an image or indicia thereon is coated with a dilute solution of pigment flakes in an ink or paint. The flakes are subsequently aligned in a magnetic field and are fixed after the field is applied. Most or all of the flakes in a region are aligned so as to be partially upstanding wherein their faces are essentially parallel. Coating the image with flakes yields a latent image which can be clearly seen at a small range of predetermined angles.

What is claimed is: 
     
       1. A security device comprising:
 a) a substrate supporting having an image thereon; 
 b) a coating of flakes supported by the substrate and in a carrier, covering the image thereby forming a latent image,; 
 wherein a first group of said flakes are aligned in a substantially same orientation at a first partially upstanding flake angle relative to said image, and wherein a second group of said flakes are aligned in a substantially same orientation at a second partially upstanding flake angle relative to said image; 
 wherein said flakes are aligned in such a manner as to obscure the image forming awherein the concentration of flakes within the carrier is dilute enough and said first partially upstanding flake angle and said second partially upstanding flake angle are oriented such that said latent image is obscured when viewing the security devicesaid security device is viewed from a first viewing angle, and to reveal the image when viewing thesaid latent image is revealed when said security device is viewed from a second viewing angle, different from the first viewing angle, wherein the coating of flakes includes a carrier supporting the flakes and wherein the concentration of flakes within the carrier is dilute enough so as to allow the latent image to be seen or to be obscured as the substrate is tilted from one direction to another, wherein a first group of the flakes are aligned in a substantially same orientation and wherein a second group of the flakes are oriented in a substantially same orientation that differs from the orientation of the first group of flakes. 
 
     
     
       2. A security device as defined in  claim 1  wherein the first group of flakes overlies a first symbol and wherein a second group of flakes overlies a second symbol wherein said first partially upstanding flake angle of said first group of flakes has an orientation that differs from the orientation of said second partially upstanding flake angle of said second group of flakes. 
     
     
       3. A security device as defined in  claim 2 , wherein the first symbol is obscured while the second symbol is revealed when viewing the substrate at a first predetermined angle. 
     
     
       4. A security device as defined in  claim 2 , wherein the first symbol is revealed while the second symbol is obscured when viewing the substrate at a second different predetermined angle. 
     
     
       5. A security device as defined in  claim 1 , wherein the flakes are at least one of color shifting, diffractive, reflective, absorbing and color switching. 
     
     
       6. A security device as defined in  claim 1 , wherein the latent image is printed with pigment flakes that are oriented so as to be parallel with the substrate. 
     
     
       7. A security device as defined in  claim 5  wherein the flakes are opaque. 
     
     
       8. A security device as defined in  claim 1 , wherein the coating is over at least 80% of the image and wherein regions of the image are uncoated with the coating. 
     
     
       9. A security device as defined in  claim 8  wherein the substrate, the image and the coating are different colors and wherein the color of at least one of the image, the coating and the substrate change with a change of viewing angle. 
     
     
       10. A security device as defined in  claim 1 , wherein the coating forms a tessellated plane pattern. 
     
     
       11. A security device as defined in  claim 1 , wherein the flakes are electrically or magnetically aligned flakes. 
     
     
       12. A security device as defined in  claim 1 , wherein the image is printed upon the substrate and wherein the coating of flakes is coated over the latent image on a same side of the substrate. 
     
     
       13. A security device as defined in  claim 1 , wherein the substrate is transparent and wherein the coating of flakes is coated on a first side of the substrate and wherein the latent image is on a second side of the substrate. 
     
     
       14. A security device as defined in  claim 1 , wherein the device exhibits at least 70% of reflectance of light incident thereon when the latent image is obscured, and wherein the device exhibits less than 40% of light incident thereon when the latent image is revealed. 
     
     
       15. A security device as defined in  claim 1 , wherein the latent image is text. 
     
     
       16. A security device as defined in  claim 1 , wherein the latent image includes one or more symbols, or a logo. 
     
     
       17. A security device as defined in  claim 1 , wherein the substrate image is printed with an ink or paint and wherein the latent image is formed by an absence of ink or paint on the printed substrate. 
     
     
       18. A security device as defined in  claim 1 , wherein the particles are flakes and wherein at least 80% of the flakes have a same shape. 
     
     
       19. A security device as defined in claim 1 wherein the first group of flakes overlies a first symbol and wherein a second group of flakes overlies a second symbol. 
     
     
       20. A security device as defined in claim 19 wherein the first symbol is obscured while the second symbol is revealed when viewing the substrate at a first predetermined angle. 
     
     
       21. A security device as defined in claim 1 wherein said first and said second groups of flakes overlie a first symbol. 
     
     
       22. A security device comprising: a substrate;
 a coating covering an image located on said substrate, said coating comprising a carrier carrying a plurality of magnetically aligned flakes;   wherein said magnetically aligned flakes are aligned in a substantially same orientation and are tilted, relative to said image, at a partially upstanding angle; and   wherein said magnetically aligned flakes cover said latent image in a dilute enough concentration, and are so aligned at said partially upstanding angle, such that said latent image is obscured when said security device is viewed from a first angle, and said latent image is revealed when said security device is viewed from a second, different angle.   
     
     
       23. A security device as defined in claim 19, wherein the first symbol is revealed while the second symbol is obscured when viewing the substrate at a second different predetermined angle.