Two-step method of coating an article for security printing by application of electric or magnetic field
View Patent ↗A two-step method of making of a security printed image is disclosed and includes coating of the surface of a substrate with a predetermined image shape with an ink containing flaked magnetic pigment in a predetermined concentration, exposing a wet printed image to a magnetic field to align magnetic particles in a predetermined manner, allowing the ink to cure, and coating the substrate with a second printed image on the top of the first image. The second printed image with the same or different image shape is printed with another ink containing clear or dyed ink vehicle mixed with flaked magnetic pigment in a low concentration, exposed to the magnetic field of the same or different configuration as the first printed image and cured until the ink is dry.
1. A method of coating an article comprising the steps of:
applying a first field orientable coating comprising flakes in an ink or paint vehicle to a first side of a substrate and using a first magnetic or electric field to orient the flakes within the first coating along field lines;
after the flakes within the first coating have been aligned, curing the first coating; and,
after the first coating has cured, subsequently applying a second magnetic coating over the first coating or over the second side of the substrate under the first coating and using a second magnetic or electric field to orient flakes within the second coating along field lines, wherein configurations of the first and second magnetic or electric fields are different from one another.
2. A method as defined in claim 1 , wherein the magnetic field for orienting the flakes within the first coating is a first magnetic field and wherein the magnetic field used to orient flakes within the second coating is a second magnetic field.
3. A method as defined in claim 1 , wherein the magnetic or electric fields are generated by different field generating systems.
4. A method as defined in claim 1 wherein a concentration of flakes in the first coating is different from a concentration of flakes in the second coating.
5. A method as defined in claim 4 , wherein one of the first and second coatings includes multilayer optically variable flakes and wherein the other of the coatings includes diffractive flakes, wherein at least some of the diffractive flakes have a surface relief pattern formed therein.
6. A method as defined in claim 1 , wherein the first and second coatings include diffractive flakes, having a surface relief pattern formed therein or thereon, and wherein flakes in the first coating are oriented along their surface relief pattern in a different orientation than diffractive flakes in the second coating.
7. A method as defined in claim 1 , wherein the flakes within the second coating are oriented differently than the flakes of the first coating.
8. A method of creating an image comprising the steps of:
applying at a first coating over a first side of a substrate;
providing a first magnetic field to align particles within the first coating in a predetermined manner;
allowing the first coating to cure or dry; and,
after the first coating has cured or dried, applying a second coating over the first coating or over a second side of the substrate under the first coating and, providing a second magnetic field before the second coating is cured or dried so as to align particles within the second coating, wherein configurations of the first and second magnetic or electric fields are different from one another.
9. A method of forming an image on a substrate comprising the steps of:
applying a first optical effect coating to a first side of the substrate and using a first magnetic or electric field to orient flakes within the coating in dependence upon the field; and,
applying a second optical effect coating over the first coating or over the second side of the substrate under the first coating and using a second magnetic or electric field to orient flakes within the coating in dependence upon the field, wherein configurations of the first and second magnetic or electric fields are different from one another, and wherein effects of both coatings, or combined effects can be seen from at least one side of the substrate.