Impressions - June/July 2017 - 51

A DTG printer's print head
and capping station should
be cleaned manually to help
avoid harmful buildup.

Think of the adhesives, and components within the printer
and print head, as behaving similarly. If water-based ink is used
in a solvent ink-delivery system, the components holding it
together will begin to break down.This is one reason why there
are so many issues with textile ink in solvent ink-based delivery
systems.When buying a DTG printer, the first question for the
manufacturer should be whether it is a solvent-based print head
and ink-delivery system. If so, it's a red flag.
It's critical to know if the encapsulation chemistry has been
tested for harmful substances and rendered safe for use on youth
and adult textiles. Not all DTG ink is OEKO-TEX certified.
If using uncertified ink, you could be harming your customers
or yourself and breaking the law if selling to children younger
than age 12.
Clogging Causes
Textile ink requires a specific viscosity level to flow through a
print head.Titanium dioxide pigment is a naturally heavy, sticky
and settling compound.When encapsulated in a carrier, white ink
sticks to everything and can have catastrophic clogging effects.
Consider this analogy:White ink acts like cholesterol in the
blood stream. If not managed, it will build up over time and
eventually clog the pathway. Another good example is a bottle
of Wite-Out correction fluid.That little bottle and brush would
become full of gunk almost immediately after a few uses, and
the same can happen with white ink in an ink-delivery system.
Specific procedures are required to mitigate the clogging
characteristics of white ink. Because titanium dioxide settles,
it must be agitated to suspend its particles. Some printers have
internal agitators, but most manufacturers require users to shake
the white-ink cartridge before use.
It's easy to shake an external printer component, but what
about the internal elements? This is where some machines stand
out and define what makes them true textile printers.All internal
elements require special attention for reliable white-ink use. Since
this ink settles, the lines and dampers need regular agitation and
ink flow. Some printers require the system to remain powered up
and will routinely flush ink through the print head, while others
require the ink to be removed and washed completely away.
This is ineffective and expensive, as the amount of ink required
to fully agitate the internal components or clean the system costs
too much to deem viable.The ultimate solution is to internally
circulate ink through the system with no ink waste.
Think of the top of that Wite-Out bottle and how much fluid
it accumulates.You can expect similar buildup on a DTG printer's

print head and capping station. In most cases, these elements must
be cleaned to reduce buildup. Manually wipe the print head
clean, even though every printer has a feature that automatically
does this. On solvent printers, it is done with a rubber squeegee.
This works, but when textile and white inks are added, the
rubber squeegee smears the latter along the bottom of the print
head and slowly clogs the nozzles. A fabric wiper is needed to
properly clean the bottom of the print head.
When shopping for a printer, be conscious of the most important
elements that make a white-ink system reliable. Is the white ink
OEKO-TEX certified and safe for children? Is the printer made
of repurposed solvent printer components and print heads or is it
designed for water-based inks? Is there internal ink circulation?
Do you need to spend time and money flushing out the white
ink? Does the printer have a fabric wiper or rubber squeegee?
Asking these simple questions can save frustration and, ultimately, your apparel-printing business. 
John LeDrew is the DTG director for Melco Intl. He has worked professionally in
garment decoration since 2006, managing accounts and overseeing production
for some of the world's largest brands and retailers. For more information or
to comment on this article, contact John via LinkedIn.

The major difference among
white inks offered by different ink
manufacturers is the encapsulation
chemistry of the DuPont pigment
in the carrier or solution.

JUNE/JULY 2017

P.51

Impressions - June/July 2017

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