Digital prints on fabrics...
Digital textile printing is
described as any ink jet based method of
printing colorants onto fabric. Most notably, digital textile printing is
referred to when identifying either printing smaller designs onto garments and
printing larger designs onto large format rolls of textile. Examples are: flags, banners
and signs.
Digital textile
printing can be divided into:
·
Direct to garment
·
Visual communication
·
Interior decoration
Digital textile
printing started in the late 1980s as a possible replacement for analog screen
printing. With the development of a dye-sublimation printer in the early
1990s, it became possible to print with low energy sublimation inks and high
energy disperse direct inks directly onto textile media, as opposed to print
dye-sublimation inks on a transfer paper and, in a separate process using a heat press,
transfer it to the fabric.
The ‘textile
market’ comprises many different applications and requirements. The intended
use of the fabric is the most important starting point to identify exactly
what’s needed to produce a specific end-product. A ‘textile’ product may vary
from natural yarns for garments,
through to synthetic fibres for flags and banners.
A ‘textile product’ can be a wall mounted banner, a stand-alone pop-up banner,
a beach flag, country flag or company flag. It can be a carpet,
back-lit frame, curtain,
room divider, building wrap, bed cover, a garment and much more.
The predominant textile media used in visual
communication is a polyester based fabric. In
the USA, nylon is often used for
flags. In northern Europe, polyspun material has been the choice of fabric for
traditional flag printing. In today’s market, a woven or knitted polyester is
the de facto standard. This differs
from the predominant coated vinyl or pvc media used in the sign and display
industry. The production process needs to fit requirements for the type of ink:
high energy sublimation (also known as disperse direct), low energy sublimation
, acid, reactive and pigment. In turn, the type of ink chemistry needs to fit
requirements for the media (such as polyester, nylon, cotton, silk). Based on
the media and ink combination, the choice comes for infra-red fixation,
heat-press sublimation or steaming. The structure of the fabric also needs
attention, for example whether it is woven, non-woven or knitted.
Polyester fabric
is printed mostly with dye-sub or disperse direct ink, although UV and solvent
inks can also be used. The great benefit of sublimation ink is the fact that
the colorants will bond with the fibre during sublimation or fixation. The
colours are ‘inside’ the media and don’t stay within the coating and on top of the
media, as it is the case with UV-curable formulations. Even latex inks on
porous textiles can suffer from abrasion or ‘rub-off’. Low energy sublimation
ink is easier to print with, but has the disadvantage of colours fading faster;
its UV resistance, or light-fastness, is less resistant than equivalents using
high energy disperse direct ink. Dye-sub can also suffer from a ‘halo’ effect
which results in less sharp images. The disperse direct ink is a ‘stronger’ ink
than the dye-sub kind, and this is very important for outdoor use, such as for
fence fabric, flags and banners: artwork will last longer.