Digital printing process

A printing process as claimed in any preceding claim, wherein the ink comprises molecules having one or more negatively charged or chargeable groups including Brønsted acid functional groups.

A printing process as claimed in any preceding claim, wherein the intermediate transfer member is a flexible endless blanket or belt of which the outer surface is the hydrophobic outer surface upon which the ink image is formed.

A printing process as claimed in any preceding claim, wherein the polymeric resin is an acrylic-based polymer selected from an acrylic polymer and an acrylic-styrene copolymer and the coloring agent consist of a pigment

A printing process as claimed in any preceding claim, wherein, prior to transferring the residue film onto the substrate, the ink image is heated to a temperature at which the residue film of resin and coloring agent that remains after evaporation of the aqueous carrier is rendered softened.

A printing system comprising an image forming station at which droplets of an ink are directed onto an intermediate transfer member to form an ink image, the ink including an organic polymeric resin and a coloring agent in an aqueous carrier, and the transfer member having a hydrophobic outer surface so that each ink droplet in the ink image spreads on impinging upon the intermediate transfer member to form an ink film;

• a drying station at which the ink is dried while the ink image is being transported by the intermediate transfer member by evaporating the aqueous carrier from the ink image to leave a residue film of resin and coloring agent;
• and an impression station at which the residue film is transferred from the intermediate transfer member to a substrate, wherein the chemical compositions of the ink and of the surface of the intermediate transfer member are selected such that attractive intermolecular forces between molecules in the outer skin of each droplet and on the surface of the intermediate transfer member counteract the tendency of the ink film produced by each droplet to bead under the action of the surface tension of the aqueous carrier, without causing each droplet to spread by wetting the surface of the intermediate transfer member.