Globally the importance of electronic print processes
is constantly gaining prominence. The growth of multi color inkjet
technology is especially growing in the home and office segments. A
substantial and thriving consumer market for inkjet can be noticed in
packaging, publication, and specialty areas.
The quality of an inkjet printing is very much influenced by the
physico-chemical properties of printing ink. Here lies the importance of
inkjet dyes. Dyes for Inkjet ink are a bit different from the usual dyes
that are available for fibers. This is because of the fact that they
need to have high purity, and do contain small salt and inorganic
matters. Dye inks are prepared by dissolving of the liquid colored dyes
into a fluid carrier. This makes the dyes easy to apply. When it is
applied to a paper, the dyes are absorbed very uniformly so they reflect
light very evenly. As the printing is a high precision job the inkjet
dyes need to have superior quality in terms of colors, physical
properties, and stability. Generally direct, reactive, and acid dyes are
used as dyes for Inkjet Ink.
Inkjet dyes can also come in the form of powders
besides the usual liquids.
Given here is a few of the inkjet dyes that are available in the powder
form along with its characteristics.
|Reactive Red 180
|Acid Red 52
||Standard for toning as well as shading
|Acid Blue 9
|Acid Yellow 23
||Red shaded Yellow (standard)
|Direct Black 168
|Direct Black 19
Functioning of the Inkjet dyes
Inkjet print images,( with dye inks) uses a
particular method of fixing the dye firmly for making the prints durable
when they are stored.
Dyes that are generally used for inkjet printers is charged to anionic,
while cationic substances are used as a fixati for the dye.
Inkjet papers that has cationic polymers, have a superlative effect in
fixing the various dyes. As the following diagram illustrates.
the right powder form Inkjet Dyes
- The powder form inkjet dyes should have a very low salt content.
- There must be the use of latest technologies like Reverse Osmosis
in the desalting process.
- Must possess a very fine particle size.
- The dyes must get easily soluble in water and other types of
- Gives the right storage options.
- Must be Environment friendly.
- Last but not the least that gets easily converted into liquid "onsite"
of Inkjet Dyes
Some of the major advantages of dyes used for inkjet
printers are listed below:
- Offers a wide gamut of colours.
- Bright intense colours.
- Wide selection.
- Stable and soluble.
of Inkjet Dyes
A few of the drawbacks as experienced by the users of
the inkjet dyes in the printers is given below.
- There is a tendency for less stabilization.
- The print is not as much thick as of a pigment based ink.
- More damage prone to attacks of sunlight ozone and ultraviolet
between Inkjet Dyes and Inkjet Pigments
There has been often a dilemma regarding the
colouring material of the ink whether to go for dye based inks or opt
for pigment based ones. Lets look at the pros and cons of both:
From the point of view of the manufacturers:-
From the point of view of users:-
- As a result of sustained efforts over the years this
technology is now very well mastered in the industry. In fact
Dye based inks started long before the time that inkjet printers
even appeared on the market.
- The technology of pigment is comparatively difficult to
master as the problem of small size of the particles to create
in large quantities must be taken into account. As nano-sized
particles have to be manufactured that will be coated in a thin
This resin is used for protection
of the pigment against external chemical and mechanical attacks.
This has a problem too as it also helps in transportation of the
particle inside the ink, through the nozzles and finally onto the
paper. Thus it is quite clear that these contradictory constraints
make this technology a difficult proposition to perfectly master.
- The ink (dye based) is usually cheap though the manufacturing
cost is only one factor in ascertaining the selling price of
- Dye is usually fragile, when exposed to light and
Ultra-violet light, the colored molecules gets broken and loose
its color. This results in the prints to loose their original
colors and fades overtime.
- Ozone and several other common pollutants are also able to
chemically break down the color molecules.
- Drying time has a direct bearing with the drying time of the
solvent on the paper (often this leads to untimely closing of
nozzles, if the ink is set to dry very fast on paper).
Consequently, if the ink and its solvent is not quickly absorbed
by the paper, there is a risk of ink flow or paper deformation.
- The Pigment based inks solution gives longevity to. It is
thus no surprise that many printers are opting for such
- Degradation of pigments by pollutants or ozone is not that
much, the presence of the resin coating limiting it further.
- Color density is generally better, or easier to achieve than
with dye-based inks.
- However talking of limitations pigments shows tendency to
promote a defect called bronzing. When brightly lit or if lit
with low incidence, the print can show unpleasant metal-like
- Manufacturing costs are higher, therefore cost of the ink is
higher to the user.