The Science of Ink

Our technical team explains the five most important ink sets in digital textile printing, and the print processes with which they are compatible. As ink and printhead technology evolve, new ink sets are becoming available. See how the ink sets and printing techniques relate to the fabric fiber composition in our fabric processing table below.

And now for the technical details of each ink set...

Dye-Sub Ink Set

Sublimation is a scientific term which describes the process by which a solid transforms into a gas without an intermediate liquid phase. This process allows color to be fixed onto polyester fabrics with a great degree of accuracy and impact, owing to a vivid color gamut. Uncoated fabrics can be used with dye-sub ink sets.

Process

In dye-sub printing, the pattern is printed using a standard inkjet printer onto a high release transfer paper. The next stage of the process is to place the paper in contact with the fabric in a high-temperature heat press. When this happens, the ink sublimates and transfers from the paper to the textile producing vivid colors in near perfect resolution on the textile.

Pigment Ink Set

Pigment inks are inks where the colorant is a fine particle dissolved and suspended in a carrier fluid. The process deposits the ink on the fabric which, when the fluid dries, allows the particles of the color to physically bond to the fabric in much the same way as a gravy stain occurs.

In recent technical developments the range, performance and clarity of colors has expanded significantly, resulting in the general suitability of pigment ink sets for all types of fabrics and fibers.

Process

In pigment printing, the ink and carrier fluid are printed together directly onto the fabric using an inkjet printer. The fabric is dried as it is printed, and fixation takes place, at approximately 302°F/150°C  in a baker or thermo-fixation device. Fabrics for pigment printing have to be pre-coated before use.

Reactive Ink Set

Reactive ink sets are organic compounds whereby through a covalent bond the dyes become a chemical part of the fiber component of the fabric being printed, thanks to a reaction between the liquid in the dyestuff and the fabric itself. The chemical bond is very strong and produces vivid colors on cottons, linens, and other cellulosic fabrics with excellent fastness properties.

Process

The printing process for reactive ink sets is complicated. First, the fabric is directly printed using an inkjet printer, and the inks are dried during the printing process. Then the fabric is processed slowly through a high-temperature steamer to fix the colors to the fabric. Finally, the fabric is washed and dried to remove any surplus color so that no fading occurs during subsequent washing. Fabrics for reactive printing have to be pre-coated before use.

Acid Ink Set

Acid ink sets are usually sodium salts of sulfonic acids, whereby the dyestuff, benefiting from an increased solubility in water in an acidic solution, creates an ionic bond with the fibers of the fabric being printed. Generally this ink set is only used to print wool, cashmere, angora, nylon and silk fabrics, where its performance in terms of clarity, fastness and intensity is exemplary.

Process

The printing process for acid ink sets, as with reactive ink sets, is complicated. First, the fabric is directly printed using an inkjet printer, and the inks are dried during the printing process. Then the fabric is processed very slowly through a high-temperature steamer to fix the colors to the fabric. Finally, the fabric is washed and dried to remove any surplus color, so that no fading occurs during subsequent washing. Fabrics for acid printing have to be pre-coated before use.

Disperse Ink Set

The disperse ink set is a low-solubility dyestuff effectively dispersed in water by powerful dispersing agents, which allow the dyestuff to be adsorbed into the interstices of the fiber, which expands under temperature to allow the dyestuff to be encased within the fiber at a molecular level.

This ink set is widely used, it is applicable to automotive and other hard-wearing fabrics comprising polyester or acetate fibers where extremely high fastness properties are demanded.

Process

The printing process for disperse ink sets, as with reactive ink sets, is complicated. First, the fabric is directly printed using an inkjet printer, and the inks are dried during the printing process. Then the fabric is processed very slowly through a high-temperature steamer to fix the colors to the fabric. Finally, the fabric is washed and dried to remove any surplus color, so that no fading occurs during subsequent washing. Fabrics for disperse printing have to be pre-coated before use.