Intermediate transfer member with paper-based layer

An intermediate transfer member (ITM) for use in a printing system, the ITM comprising:

• a. a release layer having an upper surface for ink-reception;
• and
• b. a paper-based layer disposed beneath the release layer and configured to contribute to ITM stiffness such that a ratio between (i) a spring constant in the longitudinal direction of the paper-based layer;
• and a (ii) a spring constant in the longitudinal direction of the ITM is at least 0.6, said paper-based layer including at least 50% or at least 60% or at least 80% paper fiber;
• c. a fabric layer disposed beneath the paper-based layer and configured to contribute to ITM tear resistance such that a ratio between a tear-resistance of the fabric layer in the longitudinal direction and a tear resistance of the ITM in the longitudinal direction is at least 0.6, wherein:
• i. an average surface roughness of an upper surface of the fabric layer in the ITM is at least 0.5 μm;
• and
• ii. an average surface roughness of an upper surface of the paper-based layer is at most 0.2 μm.

An intermediate transfer member (ITM) for use in a printing system, the ITM comprising:

• a. a release layer having an upper surface for ink-reception;
• and
• b. a paper-based layer disposed beneath the release layer and configured to contribute to ITM stiffness such that a ratio between (i) a spring constant in the longitudinal direction of the paper-based layer;
• and a (ii) a spring constant in the longitudinal direction of the ITM is at least 0.6, said paper-based layer including at least 50% or at least 60% or at least 80% paper fiber;
• c. a fabric layer disposed beneath the paper-based layer and configured to contribute to ITM tensile strength such that a ratio between a tensile strength of the fabric layer in the longitudinal direction and a tensile strength of the ITM in the longitudinal direction is at least 0.6, wherein:
• i. an average surface roughness of an upper surface of the fabric layer in the ITM is at least 0.5 μm;
• and
• ii. an average surface roughness of an upper surface of the paper-based layer is at most 0.2 μm.

An intermediate transfer member (ITM) for use in a printing system, the ITM comprising:

• a. a silicone-based release layer having an upper surface for ink-reception, said upper-surface for ink-reception adapted to satisfy at least one of a first structural property and a second structural property, the first and second structural properties being defined below;
• b. a paper-based layer which is impregnated with and/or coated with silicone, said paper-based layer being disposed beneath the release layer including at least 50% or at least 60% or at least 80% paper fiber, the paper-based layer configured to contribute to ITM stiffness such that a ratio between (i) a spring constant in the longitudinal direction of the paper-based layer;
• and a (ii) a spring constant in the longitudinal direction of the ITM is at least 0.5 or at least 0.6 or at least 0.7 or at least 0.8;
• c. a grip-layer disposed beneath the paper-based layer, wherein:
• A. the paper-based layer has a black upper surface and/or the ITM includes comprising an additional electromagnetic-energy-absorbing layer above the paper layer and below the release layer, said energy-absorbing layer comprising black material;
• B. according to the first structural property, a receding contact angle of a droplet of distilled water on said upper surface of said silicone-based release layer is at most 60°;
• C. according to the second structural property, for a droplet of distilled water deposited on said upper surface of said silicone-based release layer, a 10 second dynamic contact angle (DCA) is at most 108°.

A method of manufacturing the ITM of any preceding claim, the method comprising:

• a. providing a release-layer-including-structure and a paper-layer-including structure wherein:
• i. the release-layer-including structure comprises:
• A. a sheet of polyethylene terephthalate (PET);
• and
• B. the release layer of the ITM of any preceding claim disposed on the PET sheet;
• ii. the paper-layer-including structure includes the paper-based layer of any preceding claim and optionally an additional optional layer;
• b. laminating the paper-layer-including structure to the release-layer-including structure by applying an adhesive therebetween, wherein the method is performed so that an adhesion layer of the adhesive is disposed between the release layer of the ITM of any preceding claim and the paper-layer of the ITM of any preceding claim.

A method of printing, comprising:

• a. providing an intermediate transfer (ITM) of any one of the preceding claims;
• b. mounting the ITM on rollers of a printing system so that the ITM passes through multiple stations of the printing system;
• c. forming an endless ITM-loop by joining two ends of the ITM to each other;
• and
• d. rotating the ITM-loop through the multiple stations so that respective portions of the ITM successively pass (i) an image-forming station where ink images are formed by deposition of droplets of an aqueous ink upon an ITM-portion-surface and (ii) an impression station where the ink images are transferred from the ITM to a substrate.