Direct Printing on Textile

1. Pigmentary Printing

This type of printing is essentially meant for cotton or polyester cotton supports. This process is quick and simple because there are few steps.

After the printing, the pigments are fixed by a heating procedure (with a tenter, calendar or tunnel).The printing process is now finished and does not require any additional operation. In some case, the support can be prepared before with a suitable solution to obtain a better brightness of the colours and a high delicacy of the design.

This simple step to realise can be done by textile finisher during the normal preparation of the support. A digital STUDIO FX solution is available to do such operation. Printing on finished goods such as T-Shirt, tops or underclothes can be an interesting application of the pigmentary printing.

2. Fixed and washed Printing

This technique allows to print on most of the textile supports with suitable colorants. Digital printing disposes of several inks useable in the following cases:

- reactive ink : cotton, viscose, linen, hemp, ramie and eventually silk...
- acid ink : wool, silk, polyamide
- dispersed ink* : polyester, polyamide (in some conditions)

*Be aware that there are two types of dispersed ink: the direct ones for direct printing on the support and the sublimable ones to print on transfer papers for their sublimation.

The fixed and washed process is the following:

Support preparation
This preparation is required and has two main roles in the printing process. It consists in setting down different chemical products on the support. For some of them it will allow to avoid spray out phenomen on during the printing. For some others (like urea, alkali….) it will allow facilitating the colorant fixation during the steaming step. This preparation is important because it will determine the printing quality.

Support printing
This step is realised on different printers, which characteristics have to be adapted to the nature of the textile. For instance, it is better to use a printer fitted with a carpet for all elastic supports. This allows controlling the tension of the material and obtaining good results.

Support fixation
Fixation is the step that permits to fix definitively the colours on the fiber but also develop the colours. This step is most of the time done by steaming. The condition (time + temperature) depends on the nature of the textile used.

What happen in the steamer?
The water contained in the steam will condense on the support that will make the swelling of the thickener and the local dissolution of the chemical products present on the textile. Products such as urea will diffuse the colorants inside the fiber and be fixed on it.

Support washing
This last step consists in washing the supports to clean away the chemical products that are still there and the colorant not fixed. The colours are definitively fixed and the support receives its using properties. After washing, the support is dried and enrolled so that the manufacturer can use it.