Apparatuses and methods for printing security documents

Patent metadata

Field	Value
Publication number	US-11660896-B2
Application number	US-201917288678-A
Country	US
Kind code	B2
Filing date	Oct 25, 2019
Priority date	Oct 26, 2018
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

A digitally printed security document includes: a security document substrate; a first digitally printed print working on a first surface of the substrate in a first region, the first print working including a first array of printed elements arranged according to a first grid of lattice points having a first pitch; and a second digitally printed print working on the first surface of the substrate in a second region, the second print working including a second array of printed elements arranged across a second grid of lattice points having a second pitch different from the first pitch.

First claim

The invention claimed is:

1. A digitally printed security document comprising:
a security document substrate;
a first digitally printed print working on a first surface of the substrate in a first region, the first print working comprising a first array of printed dots arranged according to a first grid of lattice points having a first pitch, the first print working being printed in a first material; and
a second digitally printed print working on the first surface of the substrate in a second region, the second print working comprising a second array of printed dots arranged across a second grid of lattice points having a second pitch different from the first pitch, the second print working being printed in a second material different from the first material, the first material and the second material having different optical characteristics, wherein
the first region and the second region at least partially overlap one another such that the first print working and the second print working at least partially overlap one another on the first surface of the substrate.

2. A digitally printed security document according to claim 1 , wherein the first grid of lattice points is a two-dimensional grid of lattice points defined by a first unit cell, and wherein the second grid of lattice points is a two-dimensional grid of lattice points defined by a second unit cell, wherein the first unit cell and second unit cell are different from one another.

3. A digitally printed security document according to claim 1 , wherein at least some of the printed dots of the first array of printed dots have a smallest lateral dimension smaller than a smallest lateral dimension of the printed dots of the second array of printed dots, and/or wherein at least some of the printed dots of the second array of printed dots have a smallest lateral dimension larger than a smallest lateral dimension of the printed dots of the first array of printed dots.

4. A digitally printed security document according to claim 1 , wherein the pitch of the first grid of lattice points corresponds to a print resolution of at least 600 DPI in at least one direction, and wherein the pitch of the second grid of lattice points corresponds to a print resolution of at most 600 DPI in at least one direction.

5. A digitally printed security document according to claim 1 , wherein at least some of the printed dots of the first array of printed dots have a smallest lateral dimension of at most 200 micrometres and wherein at least some of the printed dots of the second array of printed dots have a smallest lateral dimension of at least 20 micrometres.

6. A digitally printed security document according to claim 1 , wherein the first print working comprises a printed dot on each lattice point of the first grid of lattice points across at least a sub-region of the first region such that the first array of printed dots has the first pitch across said sub-region.

7. A digitally printed security document according to claim 1 , wherein the second print working comprises a printed dot on each lattice point of the second grid of lattice points across at least a sub-region of the second region such that the second array of printed dots has the second pitch across the second sub-region.

8. A digitally printed security document according to claim 1 , wherein the first print working is printed in a first colour and the second print working is printed in a second colour different from the first colour.

9. A digitally printed security document according to claim 1 , wherein a plurality of composite printed elements are provided across the first surface of the substrate, wherein for each composite printed element one or more printed dots of the first print working are provided in proximity of one or more printed dots of the second print working such that said printed dots form said composite printed element.

10. A digitally printed security document according to claim 9 , wherein the plurality of composite printed elements vary in one or more of their size and/or shape across the first surface of the substrate by variation in the number of printed dots of the first and/or second arrays of printed dots, the positioning of the printed dots of the first and/or second arrays of printed dots, the size of the printed dots of the first and/or second arrays of printed dots, and/or the spacing of the printed dots of the first and/or second arrays of printed dots.

11. A digitally printed security document according to claim 9 , wherein the plurality of composite printed elements vary their proportional composition of printed dots of the first print working and printed dots of the second print working across the first surface of the substrate.

12. A digitally printed security document according to claim 9 , wherein one or more composite printed elements are provided in the form of an alphanumeric character, symbol, or logo.

13. A digitally printed security document according to claim 8 , wherein at least one of the first and second colours is not one of CMYK, and wherein preferably at least one of the first and second colours lies outside of the CMYK colour gamut.

14. A digitally printed security document according to claim 1 , wherein at least one of the printed dots of the first print working has a first dot thickness in a direction perpendicular to the surface of the security document substrate, and wherein at least one of the printed dots of the second print working has a second dot thickness in the direction perpendicular to the surface of the security document substrate, the second dot thickness being greater than the first dot thickness.

15. A plurality of digitally printed security documents, each according to claim 1 , wherein the first and/or second print workings provide each of the plurality of security documents with fixed content and variable content, the fixed content being the same for each of the plurality of security documents and the variable content changing between at least some of said plurality of security documents, the variable content preferably being unique to each of said plurality of security documents.

16. A method of digitally printing a security document according to claim 1 , the method comprising: digitally printing a first print working on a first surface of a security document substrate in a first region, first print working comprising a first array of printed dots arranged according to a first grid of lattice points having a first pitch, the first print working being printed in a first material; digitally printing a second print working on the first surface of the substrate in a second region, the second print working comprising a second array of printed dots arranged across a second grid of lattice points having a second pitch different from the first pitch, the second print working being printed in a second material different from the first material, the first material and the second material have different optical characteristics, wherein the first region and the second region at least partially overlap one another such that the first print working and the second print working at least partially overlap one another on the first surface of the substrate.

Assignees

• De La Rue Int Ltd

Inventors

• Parab Nikhil
• Wallis Andrew Francis
• Bannon Martin
• Augusto Da Silva Moura Miguel

Classifications

• B41J2/2125

  by means of nozzle diameter selection · CPC title

• B41M3/14

  Security printing {(securities B42D25/29)} · CPC title

• B41J3/543 Primary

  with multiple inkjet print heads (B41J2/17503, B41J2/2103 take precedence) · CPC title

• B42D25/373

  Metallic materials · CPC title

• B42D25/305

  Associated digital information (record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00) · CPC title