The present invention provides radiation-curable (UV-curable) inks and coatings for inkjet printing comprising an inert thermoplastic acrylic resin and multifunctional monomers. The inks and coatings can be applied in a single pass printing operation. Furthermore, the inks and coatings are suitable for the printing of food, pharmaceutical and other sensitive packaging materials, particularly of plastic materials. The acrylic polymer (or copolymer) preferably has a molecular weight of 10,000 g/mole, or less, and the ink comprises less than 5 wt % of any blend of monofunctional monomer. The inks and coatings of the invention are particularly suitable for curing by UV-LED radiation.

The present invention provides radiation-curable (UV-curable) inks and coatings for inkjet printing comprising an inert thermoplastic acrylic resin and multifunctional monomers. The inks and coatings can be applied in a single pass printing operation. Furthermore, the inks and coatings are suitable for the printing of food, pharmaceutical and other sensitive packaging materials, particularly of plastic materials. The acrylic polymer (or copolymer) preferably has a molecular weight of 10,000 g/mole, or less, and the ink comprises less than 5 wt % of any blend of monofunctional monomer. The inks and coatings of the invention are particularly suitable for curing by UV-LED radiation.

A multi-pass UV inkjet printer for outputting high glossy varnish and a printing method using the same includes providing a side UV light irradiation device at a side of an inkjet module and a front UV light irradiation device in front of the inkjet module not overlapped by a varnish print head. During output of the varnish, varnish outputted on a substrate in the n.sup.th pass is passed under the side UV light irradiation device with a lower UV irradiation power during or after the n+1.sup.th pass performed by the UV inkjet printer for shaping or temporarily not curing, and then during or after the next pass, the varnish is passed under the front UV light irradiation device with a higher UV irradiation power for complete curing, thereby increasing production yield.

A multi-pass UV inkjet printer for outputting high glossy varnish and a printing method using the same includes providing a side UV light irradiation device at a side of an inkjet module and a front UV light irradiation device in front of the inkjet module not overlapped by a varnish print head. During output of the varnish, varnish outputted on a substrate in the n.sup.th pass is passed under the side UV light irradiation device with a lower UV irradiation power during or after the n+1.sup.th pass performed by the UV inkjet printer for shaping or temporarily not curing, and then during or after the next pass, the varnish is passed under the front UV light irradiation device with a higher UV irradiation power for complete curing, thereby increasing production yield.

A liquid ejection device that ejects an ultraviolet-curable liquid includes an inkjet head, which is an ejection head that ejects the ultraviolet-curable liquid; a scanning driver that causes the inkjet head to perform a main scan; an ultraviolet generator; and a light source driver; where the ultraviolet generator irradiates the ultraviolet while moving in the main scanning direction together with the inkjet head; the ultraviolet generator includes a plurality of UV LED elements; the plurality of UV LED elements are arranged such that a light emitting range overlaps a range of the nozzle row in a sub scanning direction; and the light source driver drives the plurality of UV LED elements such that an illuminance at an end portion in the sub scanning direction is larger than an illuminance at a central portion in the light emitting range.

An aqueous ink composition including water; an optional co-solvent; an optional colorant; a sulfonated polyester; and a polyurethane. A process of digital offset printing including applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature. A process including combining a water; an optional co-solvent; an optional colorant; a sulfonated polyester; and a polyurethane to form an aqueous ink composition.

An aqueous ink composition including water; an optional co-solvent; an optional colorant; a sulfonated polyester; and a polyurethane. A process of digital offset printing including applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature. A process including combining a water; an optional co-solvent; an optional colorant; a sulfonated polyester; and a polyurethane to form an aqueous ink composition.

A multi-pass UV inkjet printer for outputting high glossy varnish and a printing method using the same includes providing a side UV light irradiation device at a side of an inkjet module and a front UV light irradiation device in front of the inkjet module not overlapped by a varnish print head. During output of the varnish, varnish outputted on a substrate in the n.sup.th pass is passed under the side UV light irradiation device with a lower UV irradiation power during or after the n+1.sup.th pass performed by the UV inkjet printer for shaping or temporarily not curing, and then during or after the next pass, the varnish is passed under the front UV light irradiation device with a higher UV irradiation power for complete curing, thereby increasing production yield.

A multi-pass UV inkjet printer for outputting high glossy varnish and a printing method using the same includes providing a side UV light irradiation device at a side of an inkjet module and a front UV light irradiation device in front of the inkjet module not overlapped by a varnish print head. During output of the varnish, varnish outputted on a substrate in the n.sup.th pass is passed under the side UV light irradiation device with a lower UV irradiation power during or after the n+1.sup.th pass performed by the UV inkjet printer for shaping or temporarily not curing, and then during or after the next pass, the varnish is passed under the front UV light irradiation device with a higher UV irradiation power for complete curing, thereby increasing production yield.

An ink composition including a humectant blend comprising a first humectant and a second humectant; wherein the first humectant has a freezing point; wherein the second humectant suppresses the freezing point of the first humectant such as to impart to the ink composition the characteristic of being able to be stored at a desired temperature without solidifying; water; an optional co-solvent; an optional colorant; and a sulfonated polyester. A process of digital offset printing using the ink composition.