Method for printing a colour pixel matrix on a physical medium by printing oblique lines and associated control device

1. A method for printing each pixel of a matrix of M*P pixels with a single colour amongst N colours, said N colours defining a colour coding system, on a selected part of a physical medium, said method further comprising laser personalization of said printed pixels in different shades of grey or black pixels or white pixels or transparent pixels in light-sensitive layers that are placed on top of said matrix of printed pixels, said method comprising a stage during which colours are printed in at least one pass along oblique lines of pixels in relation to said physical medium, wherein the pixels of an oblique line are all printed in the same colour selected from said N colours, different from that used for the previous oblique line, in order to generate a matrix of M horizontal lines comprising P pixels each in said N colours successively in a selected order, with the possible repetition of said order when P is greater than N, and wherein each horizontal line other than the first one comprises a first pixel that is identical to the second pixel of the previous horizontal line, whereby possible errors in the positioning of the pixels essentially occur along the oblique movement direction and not along the direction of the horizontal lines.

2. A method according to claim 1 , wherein a preliminary stage is included wherein said physical medium is turned by a selected angle so as to make up the matrix (MPC) along oblique lines slanted to said selected angle, where all the pixels in each of them are in the same colour.

3. A method according to any of claims 1 or 2 , wherein said printing is carried out using the ink jet process.

4. A method according to any of claims 1 or 2 , wherein said printing is carried out using the offset printing process.

5. A method according to any of claims 1 to 4 , wherein said colour coding system is selected from a group comprising at least the (Red, Blue, Green) system, the (Yellow, Magenta, Cyan) system and a combination of the two previous systems.

6. A device to control a printing system for printing a matrix of M*P pixels in N colours defining a colour coding system on a selected part of a physical medium, said device comprising

printing system to print colours in at least one pass along oblique lines in relation to said physical medium, wherein the pixels of an oblique line are all in the same colour selected from said N colours, different from that used for the previous oblique line, in order to generate a matrix of M horizontal lines comprising P pixels each in said N colours successively in a selected order, with the possible repetition of that order when P is greater than N, and wherein each horizontal line other than the first one comprises a first pixel that is identical to the second pixel of the previous horizontal line, and

modifying means organized to carry out laser printing of pixels in different shades of grey or black pixels or white pixels or transparent pixels in light-sensitive layers of said physical medium that are placed on top of said matrix, corresponding with said colour pixels of said matrix respectively.

7. A printing system for printing a pixel diagram in N colours defining a colour coding system on a selected part of a physical medium, comprising:

a device according to claim 6 .

8. A printing system according to claim 7 , further comprising supporting means capable of receiving said physical medium in a position turned by a selected angle so that said matrix is made up along oblique lines slanted by that selected angle, and where all the pixels in each of them are in the same colour.

9. A system according to any of claims 7 , comprising printing means organised to carry out said ink jet printing.

10. A system according to any of claims 7 or 8 , comprising printing means organised to carry out said offset printing.

11. A system according to any of claims 7 to 10 , wherein said colour coding system is selected from a group comprising at least the (Red, Blue, Green) system, the (Yellow, Magenta, Cyan) system and a combination of the two previous systems.