Intermediate transfer member
An intermediate transfer member (ITM) for use with a printing system, the ITM having (a) a support layer; and (b) a release layer having an ink reception surface and a second surface opposing the ink reception surface, the second surface attached to the support layer, the release layer formed of an addition-cured, hydrophobic silicone material, wherein the release surface of the release layer has relatively hydrophilic properties with respect to the addition-cured, hydrophobic silicone material.
1. A method of operating an indirect printing system, the method comprising:
(a) providing a quantity of an aqueous ink and an intermediate transfer member (ITM) having a release layer having an ink reception surface; and
(b) jetting droplets of the aqueous ink onto the ink reception surface of the ITM to form an ink image on the ink reception surface,
wherein:
I. the release layer is formed of a silicone material;
II. the ink reception surface of the release layer is adapted to satisfy at least one of the following structural properties:
(i) a receding contact angle of a droplet of distilled water on said ink reception surface is at most 60°; and
(ii) for a droplet of distilled water deposited on said ink reception surface, a 10 second dynamic contact angle (DCA) is at most 108°; and
III. the release layer has at least one of the following structural properties:
(1) said silicone material consisting essentially of a silicone, or containing, by weight, at least 95% of said silicone; and
(2) functional groups make up at most 5%, by weight, of said silicone material.
2. The method of claim 1 , wherein said receding contact angle is at most 58°, at most 56°, at most 54°, at most 52°, at most 50°, at most 48°, at most 46°, at most 44°, at most 42°, at most 40°, at most 38°, or at most 37°.
3. The method of claim 1 , wherein said functional groups make up at most 3%, at most 2%, at most 1%, at most 0.5%, at most 0.2%, or at most 0.1%, by weight, of said silicone material, or wherein said silicone material is substantially devoid of said functional groups.
4. The method of claim 1 , wherein a polyether glycol functionalized polydimethyl siloxane is impregnated in said silicone material.
5. The method of claim 1 , wherein a total surface energy of the ink reception surface is at least 2 J/m 2 , at least 3 J/m 2 , at least 4 J/m 2 , at least 5 J/m 2 , at least 6 J/m 2 , at least 8 J/m 2 , or at least 10 J/m 2 higher than a total surface energy of a modified ink reception surface produced by subjecting an ink reception surface of a corresponding release layer to 160° C. for 2 hours.
6. The method of claim 1 , wherein the silicone material is a cured silicone material, and wherein a total surface energy of the ink reception surface is at least 4 J/m 2 , at least 6 J/m 2 , at least 8 J/m 2 , at least 10 J/m 2 , at least 12 J/m 2 , at least 14 J/m 2 , or at least 16 J/m 2 more than a total surface energy of hydrophobic ink reception surface of a corresponding release layer prepared by standard air exposure curing of a silicone precursor of the cured silicone material.
7. The method of claim 1 , wherein the silicon material is a silicone cured material, and wherein a receding contact angle of a droplet of distilled water on the ink reception surface is at least 7°, at least 8°, at least 10°, at least 12°, at least 15°, at least 18°, or at least 20° lower than a receding contact angle of a droplet of distilled water on an ink reception surface of a corresponding release layer prepared by air exposure curing of a silicone precursor of the cured silicone.
8. The method of claim 1 , wherein: (i) the release layer of the ITM further has a second surface opposing the ink reception surface, (ii) the release layer is adapted such that polar groups of the ink reception surface have an orientation away from or opposite from the second surface.
9. The method of claim 1 , wherein the release layer is adapted such that when the ITM is in an operative mode, with said ink reception surface exposed to an ambient environment, said polar groups of the ink reception surface have an orientation towards or facing said ambient environment.
10. The method of claim 1 , wherein said release layer contains, within a silicone polymer matrix thereof, a total amount of at most 3%, at most 2%, at most 1%, at most 0.5%, at most 0.2%, or substantially 0% of functional groups, by weight.
11. The method of claim 1 , wherein said release layer contains, within a silicone polymer matrix thereof, a total amount of at most 3%, at most 2%, at most 1%, at most 0.5%, at most 0.2%, or substantially 0%, by weight, of functional groups selected from the group of moieties consisting of C═O, S═O, O—H, and COO.
12. A method of setting up a mounted-ITM system for use in indirect printing, the method comprising:
(a) providing an intermediate transfer member (ITM) having a release layer having an ink reception surface; and
(b) mounting the ITM over drum or over a plurality of rollers,
wherein:
I. the release layer is formed of a silicone material;
II. the ink reception surface of the release layer is adapted to satisfy at least one of the following structural properties:
(i) a receding contact angle of a droplet of distilled water on said ink reception surface is at most 60°; and
(ii) for a droplet of distilled water deposited on said ink reception surface, a 10 second dynamic contact angle (DCA) is at most 108°; and
III. the release layer has at least one of the following structural properties:
(1) said silicone material consisting essentially of a silicone, or containing, by weight, at least 95% of said silicone; and
(2) functional groups make up at most 5%, by weight, of said silicone material.
13. The method of claim 12 , performed so that after set-up, a location on the ITM is disposed relative to a printing station such that the printing station is configured to form ink images on the ink reception surface of the ITM.
14. The method of claim 12 wherein the ITM is mounted over a plurality of rollers as a belt-like structure.
15. The method of claim 14 , performed so that after set-up, a location on the ITM is disposed relative to a printing station such that the printing station is configured to form ink images on the ink reception surface of the ITM.
16. The mounted-ITM printing system of claim 12 wherein the silicone material from which the release layer is formed is a cured silicone material and wherein at least one of the following is true:
(1) said cured silicone material consisting essentially of cured silicone, or containing, by weight, at least 95% of said addition-cured silicone;
(2) functional groups make up at most 5%, by weight, of said cured silicone material.
17. The method of claim 12 wherein the silicone material from which the release layer is formed is an addition-cured silicone material and wherein at least one of the following is true:
(1) said addition-cured silicone material consisting essentially of an addition-cured silicone, or containing, by weight, at least 95% of said addition-cured silicone;
(2) functional groups make up at most 5%, by weight, of said addition-cured silicone material.
18. The method of claim 12 , wherein; (i) the release layer of the ITM further has a second surface opposing the ink reception surface, (ii) the release layer is adapted such that polar groups of the ink reception surface have an orientation away from or opposite from the second surface.
19. The method of claim 12 , wherein the release layer is adapted such that when the ITM is in an operative mode, with said ink reception surface exposed to an ambient environment, said polar groups of the ink reception surface have an orientation towards or facing said ambient environment.