Blanket cylinder for an intaglio printing machine

1. A blanket cylinder for an intaglio printing machine comprising at least a plate cylinder carrying printing plates with engravings corresponding to a specific intaglio structure to be printed on a substrate, and cooperating with an impression cylinder carrying a substrate to be printed, the blanket cylinder having at least one blanket on which the ink in the different colours is deposited by selector cylinders, each selector cylinder receiving ink of a given colour and having reliefs with contours corresponding to the area of the intaglio structure to be inked with said given colour, wherein said at least one blanket comprises an engraved lipophilic surface layer having non-engraved areas corresponding to the intaglio structure to be inked on said plate cylinder.

2. A blanket cylinder as defined in claim 1 , wherein said engraved lipophilic surface layer is disposed over a lipophobic layer, said lipophobic layer being exposed in the areas where the lipophilic surface layer is engraved to repel ink to the non-engraved areas of said lipophilic surface layer.

3. An intaglio printing machine characterized by at least one blanket cylinder as defined in claim 2 .

4. An intaglio printing machine characterized by at least one blanket cylinder as defined in claim 1 .

5. A method for making a blanket cylinder according to claim 1 , comprising the following steps:

mounting a non-engraved blanket on the blanket cylinder of the intaglio printing machine, said non-engraved blanket comprising at least an engravable lipophilic surface layer;

inking the blanket cylinder with its non-engraved blanket with the selector cylinders;

transferring the ink deposited on the blanket cylinder onto the plate cylinder;

wiping the surface of the plate cylinder to remove ink excess outside the engravings of the printing plate;

transferring again the ink from the plate cylinder to the blanket cylinder so as to form a structure on the blanket which corresponds exactly to the intaglio structure to be inked; and

engraving the lipophilic surface layer in the areas where this lipophilic surface layer is not covered by the said structure.

6. The method of claim 5 , wherein the lipophilic surface layer is engraved by means of a laser.

7. A blanket cylinder for an intaglio printing machine comprising at least a plate cylinder carrying printing plates with engravings corresponding to a specific intaglio structure to be printed on a substrate, and cooperating with an impression cylinder carrying a substrate to be printed, the blanket cylinder having at least one blanket on which the ink in the different colours is deposited by selector cylinders, each selector cylinder receiving ink of a given colour and having reliefs with contours corresponding to the area of the intaglio structure to be inked with said given colour, wherein said at least one blanket comprises an engraved lipophobic surface layer having engraved areas corresponding to the intaglio structure to be inked on said plate cylinder.

8. A blanket cylinder as defined in claim 7 , wherein said engraved lipophobic surface layer is disposed over a lipophilic layer, said lipophilic layer being exposed in the areas where the lipophobic surface layer is engraved to accumulate ink between the non-engraved areas of said lipophobic surface layer.

9. An intaglio printing machine characterized by at least one blanket cylinder as defined in claim 7 .

10. An intaglio printing machine characterized by at least one blanket cylinder as defined in claim 8 .

11. A method for making a blanket cylinder according to claim 7 , comprising the following steps:

mounting a non-engraved blanket on the blanket cylinder of the intaglio printing machine, said non-engraved blanket comprising at least an engravable lipophobic surface layer;

inking the blanket cylinder with its non-engraved blanket with the selector cylinders;

transferring the ink deposited on the blanket cylinder onto the plate cylinder;

wiping the surface of the plate cylinder to remove ink excess outside the engravings of the printing plate;

transferring again the ink from the plate cylinder to the blanket cylinder so as to form a structure on the blanket which corresponds exactly to the intaglio structure to be inked; and

engraving the lipophobic surface layer in the areas where this lipophobic surface layer is covered by the said structure.

12. The method of claim 11 , wherein the lipophobic surface layer is engraved by means of a laser.