Methods of inkjet printing

Ink jet printing apparatus comprising a substrate path;

• an undercoat station for forming a UV curable undercoat layer on a substrate;
• at least one ink jet printhead positioned downstream of the undercoat station in the substrate path for depositing ink droplets onto the undercoat whilst while it remains wet;
• and a UV curing station downstream in the substrate path of the at least one printhead.

A method of ink jet printing on a substrate, comprising the steps of ink jet printing an undercoat layer on the substrate, the thickness of that layer varying across the substrate in accordance with the thickness of the ink to be deposited, and ink jet printing ink onto the undercoat, wherein the thickness of the undercoat layer varies generally inversely with the number of ink droplets deposited in a local region.

A method of ink jet printing utilizing at least two print components having different optical density, comprising the steps of depositing at respective elemental print areas varying numbers of droplets of the respective print components, wherein the relative numbers of ink droplets from the respective print components are controlled to produce the desired print density and wherein the aggregate number of droplets deposited at each elemental print area is substantially constant.

A method of ink jet printing on a substrate, comprising the steps of forming a wet undercoat layer on the substrate, depositing onto the undercoat layer, while the undercoat layer remains wet, a pattern of wet ink droplets and subsequently transforming the undercoat layer and deposited ink droplets to a dry state, and wherein the step of forming the undercoat layer comprises the step of forming a layer that varies spatially with the pattern of ink deposited wherein the spatial variation is the thickness of the undercoat layer and wherein the thickness of the undercoat layer varies generally inversely with the number of ink droplets to be deposited in a local region.