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
Understanding the Chemistry of Inkjet DyesAs inkjet dyes are indispensable today, no doubt a
better understanding of the chemistry of inkjet dyes will certainly lead
to a smoother quality finish and add more longevity for the printed
item. Researches were done at Helsinki University of Technology
to understand the light fastness of inkjet prints for the first time.
They applied the Kerr gated resonance Raman spectroscopy for this. In
this process, the excitation wavelength was used to selectively raise
the Raman signals from the dye molecules of the printing colours. It was
found that the Kerr gate rejected fluorescence of the dyes, inorganic
pigments and the strong fluorescent optical brighteners. The
interactions between the dyes and the coating polymers were studied from
shifts in the Raman signals of the dyes. The light induced changes that
took place in the chemical structure of the dyes were detected as
changes as a result of the intensity of the Raman bands that
corresponded to specific chromophores in the dye. |
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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.
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Given here is a few of the inkjet dyes that are available in the powder form along with its characteristics.
| CI Name | CI Number | Concentration | Quality | Characteristics |
| Reactive Red 180 | 181055 | 100.00% | Salt-free/RO | Magenta (standard) |
| Acid Red 52 | 45100 | 400.00% | Low salt | Standard for toning as well as shading |
| Acid Blue 9 | 42090 | 165.00% | Low salt | Cyan (standard) |
| Direct Blue199 | 74190 | 175.00% | Salt-free/ RO | Greenish blue |
| Acid Yellow 23 | 19140 | 200.00% | Salt-free/RO | Red shaded Yellow (standard) |
| Direct Black 168 | 30410 | 165.00% | Salt-free/RO | Standard |
| Direct Black 19 | 35255 | 200.00% | Salt-free/RO | Standard |
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.
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 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 co-solvents.
- Gives the right storage options.
- Must be Environment friendly.
- Last but not the least that gets easily converted into liquid "onsite"
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.
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 rays.
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:-
From the point of view of the manufacturers:-
| Dye based Ink | Pigment Ink |
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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. |
From the point of view of users:-
| Dye Based Ink | Pigment Ink |
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