3
Inkjet Technology Overview
In the early days of inkjet print technology development,
poor colour image quality due to ink spreading and
inter-colour bleeding (that is where the penetration of
ink into the paper is too slow to absorb multiple ink
drops on the same spot in short intervals) were widely
recognized as the critical issues.
The initial solution which has continued to be built upon
was the use of special coated media, the design of which
takes into account drop volume, evaporation rate,
penetration rate, porosity, etc (see Designs on Inkjet
Paper, page 11).
But as inkjet print technology was developed and
alternative solutions to the use of special coated media
were sought, the use of solid (hot-melt) ink was
introduced.
The idea being that on contact with the media, the ink
solidifies almost immediately, without over-absorption or
too much spreading, enabling brilliant colour and image
reproduction. These inks have the advantage of being
able to print on a wide variety of substrates such as
glass and ceramics. However, they do not allow for a
very high print resolution, hence at present the
technology is not a market leader.
With this potential alternative solution, the door was now
open to deeper exploration of the true opportunities of
inkjet printing.
Continuous inkjet technology (The process in which a
continuous stream of ink droplets are given an
electrostatic charge which allows precise placement and
frequency of droplets) and drop-on-demand inkjet
technology (The procedure in which droplets of ink are
forced through a nozzle in a controlled fashion, rather
than in a continuous stream), soon became the two
primary categories (see Chart 1), spawning their own
technology sub-divisions. However, drop-on-demand is
at present the most widely used technology with the vast
majority of applications being printed using this method.
W
HEN INKJET PRINTING FIRST CAME ON THE SCENE PRINT QUALITY WAS
GENERALLY UNSATISFACTORY
. H
OWEVER
,
DUE TO DEVELOPMENTS IN HARDWARE
(
PRINTERS
),
SOFTWARE
,
INKS AND SUBSTRATES
,
VERY GOOD PRINTED RESULTS
CAN NOW BE ACHIEVED
. (I
MPROVED PRINT QUALITY IS NOT ONLY DOWN TO BETTER
PAPER
,
BUT A VARIETY OF CHANGES IN THE WHOLE ARENA
)
