Ink Tester for Functional Printing: Find Out If Your Ink Jets Before It Reaches a Production Printhead

Key facts

• What it is: The Ink Tester is a fast jettability testing instrument from Digital Sign Technologies (DST), Mississauga, Ontario, Canada.

• What it does: It evaluates how an ink actually behaves through a printhead and whether the fluid jets reliably.

• Reference head: Users can test with their own new printhead or with a printhead that is confirmed to be in perfect condition. Alternatively, DST can supply a brand-new printhead, allowing the fluid to be assessed against a known-good reference rather than a used head of unknown condition.

• Modular ink system: Each ink runs in its own dedicated module, and additional modules can be added. This allows one instrument to test multiple inks with no cross-contamination and no flushing required between fluids.

• Where it sits: Before production. It answers the question, “Will this fluid jet?” so an unproven ink does not have to be validated on a production printhead.

• Related products: The Print Head Doctor (recovery) and Print Head Tester (nozzle health verification) work together with the Ink Tester to form a complete end-to-end system.

Every functional ink developer knows the moment: a promising new formulation, a production printhead worth thousands, and no way to find out whether the two are compatible except to try.

Trying is expensive. If the fluid does not jet, you have lost development time. If it jets badly, you have lost a batch. If it settles, sediments or attacks the head, you may have lost the head — and the machine it was in is down while you find that out.

Functional inks make this harder than conventional colour work. They are heavily loaded with metal, ceramic or biological content. They are formulated for what the deposited layer must do — conduct, insulate, adhere, sinter, remain viable — with jetting behaviour treated as a constraint to solve afterwards rather than a starting point. And they usually exist in small, precious quantities exactly when you most need to test them.

Why is jettability not something you can read off a datasheet?

Because viscosity and surface tension describe a fluid at rest, and jetting is what a fluid does in a nozzle. Two inks with matching bulk properties can behave completely differently: one forms a clean drop, the other tails, produces satellites, mists, refuses to refill, or starts well and degrades over a few thousand cycles as particles migrate.

Jetting behaviour is what the fluid does in a real nozzle, under a real waveform, at real firing frequencies. The only reliable way to know it is to jet it. The question is what you are willing to risk to find out.

Why standalone ink testing is critical for functional printing

Most teams discover how a fluid jets by putting it into a production press and watching what happens. For colour graphics that is a survivable experiment. For functional work it is a poor one, for three reasons:

• The hardware at risk is expensive. An industrial printhead is among the most costly consumables in the building, and functional fluids are the most punishing things to run through one. Learning that a formulation sediments inside a nozzle is much cheaper on a dedicated instrument than on a head in a press.

• A production head confuses the result. If you test a new ink through a head that has already run thousands of hours, a poor result is ambiguous — the fluid may be at fault, or the head may simply be tired. You have two unknowns and one measurement.

• The press is not available for experiments. Development work competes with production for the machine, so tests get deferred, batched, or skipped — and decisions get made on assumption instead of evidence.

What is an Ink Tester and what does it measure?

The Ink Tester is a dedicated instrument for fast jettability testing. It evaluates how an ink actually behaves through a printhead — on its own bench, away from production hardware — so an unproven fluid never has to be proven on a production head.

It is used to establish whether a fluid jets reliably: whether it forms clean drops, whether that behaviour holds over sustained firing rather than only in the first few seconds, and whether the formulation is stable enough to put in front of a customer or into a machine.

Speed matters here for the same reason it does in head testing. Testing that takes minutes gets used on every candidate formulation. Testing that takes days gets used only on the finalists — after the early decisions have already been made blind.

Why is a known-good printhead essential for ink testing?

Because a fluid can only be evaluated fairly against a printhead in perfect condition—ideally, a brand-new printhead.

This is a key distinguishing feature of the Ink Tester configuration, and for ink testing, it is essential. Users can either use their own brand-new printhead or a printhead confirmed to be in perfect condition. Alternatively, DST can supply a brand-new printhead, so the head serves as a known-good reference rather than another variable.

When a test goes badly, the result points to the ink—not to a nozzle plate that may already be worn or compromised.

That single design decision removes much of the ambiguity that makes press-based ink testing so frustrating: you are no longer trying to separate a fluid problem from a hardware problem using a single result that contains both.

How does the modular ink system handle multiple inks?

Each ink runs in its own dedicated ink module, and additional modules can be added as you need them — so one instrument tests multiple inks rather than being tied to a single fluid.

Changing ink is a module swap, not a flushing procedure. There is no lengthy cleanout between fluids and no risk of one formulation contaminating the next.

Modules run one at a time, so a multi-ink comparison is a sequence of clean, isolated tests.

For development work that is exactly the right shape. Screening candidates means running a series of formulations, and each one deserves a test that is not compromised by whatever ran before it. For a developer working through a set of candidates, this is the difference between a day of testing and a day of cleaning.

When should you test an ink?

Test a fluid at four points: when a new formulation is first ready, before any customer trial, when a supplier changes anything, and before an unproven ink meets production hardware.

1. On a new formulation. Find out early whether a promising chemistry is jettable at all, while changing it is still cheap.

2. Before a customer trial. A fluid that fails at a customer's site costs far more than the trial — it costs the relationship.

3. On a new batch or a changed supply. Pigment lots, dispersants and carriers drift. A fluid that jetted last quarter is not guaranteed to jet this quarter.

4. Before it reaches a production head. The last check before an unproven fluid meets hardware you cannot afford to lose.

Which industries use an ink tester for functional printing?

Any industry developing or qualifying fluids where the jetted material becomes part of the finished product. In these applications the fluid is engineered for what it must do after landing — conduct, insulate, cure, sinter, remain biologically viable — which is precisely what makes it difficult to jet. Established sectors first, then the fast-growing ones.

Established: where functional inkjet already runs in production

Industry	Fluids being qualified	Why jettability testing matters
Printed electronics and circuit boards (PCBs)	Conductive silver and copper inks, dielectrics, solder mask, etch resist	The largest functional inkjet sector. Metal-loaded inks agglomerate and sinter inside nozzles, so a formulation that jets on day one may not on day thirty
Ceramics, glass, laminate and décor	Pigmented, abrasive, high-solids decoration fluids	Heavy particle loading settles and abrades. Stability over sustained firing matters more than first-drop behaviour
Additive manufacturing and 3D printing	Binders for powder beds, ultraviolet-cured build materials	Reactive chemistries can cure inside the nozzle. A binder must jet identically for the hours a build takes
Functional coatings and adhesives	Conformal coatings, jetted adhesives, release and hydrophobic layers	Formulated for adhesion and cure, not for jetting — so jettability is usually the constraint that has to be solved last
Packaging, labels and industrial coding	Functional and security inks	Fluids qualified once and then run at volume, where a stability problem becomes an expensive problem quickly
Textiles and technical fabrics	Pigment dispersions and functional finishes	Dispersion stability is the recurring failure mode, and it only shows up under sustained jetting

Strategic: where functional printing is growing fastest

Industry	Fluids being qualified	Why it matters
Solar and photovoltaics	Silver metallisation pastes, perovskite precursors, passivation coatings	Highly loaded pastes at the edge of what can be jetted. Perovskite precursor formulation is an active research field, and every candidate needs jettability data
Display manufacturing	Organic light-emitting diode (OLED) inks, quantum-dot formulations	Extremely tight uniformity requirements, with formulations under constant development
Semiconductor advanced packaging	Dielectric and redistribution-layer materials	The tightest tolerances of any application here — fluid behaviour must be characterised, not assumed
Life sciences, diagnostics and bioprinting	Reagents, cell suspensions, hydrogels, deoxyribonucleic acid (DNA) solutions	Biological fluids are shear-sensitive and easily fouled; jetting must be verified without destroying what is being jetted
Battery, hydrogen and energy	Electrode slurries, separator coatings, fuel-cell catalyst inks	High solids content with precious-metal loading. Both jettability and material efficiency are at stake
Automotive direct-to-shape painting	Paints engineered for direct application with no overspray	A paint reformulated for jetting is a genuinely new fluid and behaves like one

The common thread: functional fluids are formulated for the job the deposited layer must do, and jetting is the constraint that has to be satisfied afterwards. That is exactly why jettability has to be measured rather than predicted.

How do the Print Head Doctor, Print Head Tester and Ink Tester work together?

The Ink Tester is not a standalone instrument. With the Print Head Doctor and the Print Head Tester, it forms an end-to-end system covering the full working life of a printhead and the fluid that runs through it:

• Print Head Doctor — recover. Restores clogged, degraded and underperforming printheads instead of replacing them.

• Print Head Tester — verify. Evaluates printhead nozzle health, in about three minutes, before and after service.

• Ink Tester — qualify. Determines whether a fluid jets properly in the first place, before it ever reaches a production head.

For ink development specifically, that chain answers a question every formulator has faced: when a test goes wrong, was it the ink or was it the head? With all three, you are never guessing. Verify the head, qualify the fluid against it, and if the head suffers along the way — which happens when you are deliberately pushing unproven formulations — recover it and verify again rather than writing it off.

Qualify the ink → verify the head → recover what is recoverable → verify again. One loop, one supplier, no finger-pointing between them.

Can one device test both inks and printheads?

Yes. The Ink Tester and the Print Head Tester are one device with dual functionality — the same platform answers both questions.

As the Print Head Tester (PHT), it addresses the complementary question: not "will this fluid jet?" but "is this printhead still fit to print?", assessing nozzle health in about three minutes whether a head is new, stored or freshly recovered. The difference in configuration is the reference head: the Ink Tester comes with a brand-new printhead, because ink work requires a known-good baseline. That side is described at PrintHeadTester.com.

The bottom line

In functional printing, the ink is the product. Whether it jets is not a detail to be discovered in production — it is a property to be measured before an expensive head, an expensive substrate and an expensive schedule are committed to it.

Fail early, on a dedicated instrument, on purpose.

Frequently asked questions

What is an ink tester?An ink tester is an instrument that evaluates how a fluid behaves when jetted through a printhead and whether the fluid jets reliably at all. The DST Ink Tester performs fast jettability testing on a dedicated bench instrument rather than on production hardware.

What is the difference between the Ink Tester and the Print Head Tester?They are one device with two configurations. The Ink Tester comes with a brand-new printhead, or users can use their own brand-new printhead or a printhead confirmed to be in perfect condition, so the fluid is assessed against a known-good reference head. The Print Head Tester does not include a new printhead because its purpose is to measure the condition of the printhead you already have.

Why can't jettability be predicted from viscosity and surface tension?Because those numbers describe a fluid at rest. Two inks with matching bulk properties can jet completely differently — one forming clean drops, the other tailing, producing satellites, misting or failing to refill. Jetting behaviour has to be observed in a real nozzle under a real waveform.

Can it test more than one ink?Yes. Each ink runs in its own dedicated ink module and additional modules can be added, so one instrument tests multiple inks. Changing ink is a module swap rather than a flushing procedure, which avoids cross-contamination. Modules run one at a time, so multi-ink comparisons are sequential.

Who uses an ink tester?Ink manufacturers and formulators screening candidate formulations, functional printing developers qualifying a fluid for a specific head, equipment builders matching a customer's fluid to a head choice, and anyone about to run an unproven fluid through hardware they cannot afford to lose.

Which industries use an ink tester?Established sectors include printed electronics and circuit boards (PCBs), ceramics and décor, additive manufacturing, functional coatings and adhesives, packaging and industrial coding, and technical textiles. Fast-growing sectors include solar and photovoltaics, display manufacturing, semiconductor advanced packaging, life sciences and bioprinting, battery and hydrogen energy, and automotive direct-to-shape painting.

How does it relate to the Print Head Doctor?The Ink Tester qualifies the fluid, the Print Head Tester verifies the head, and the Print Head Doctor recovers heads that have degraded. Together they form an end-to-end system for the working life of a head and the fluid running through it.

Who makes the Ink Tester?Digital Sign Technologies (DST), based in Mississauga, Ontario, Canada.

To discuss the Ink Tester, Print Head Tester, or Print Head Doctor, or to schedule a demo, contact us via the Contact Form, WhatsApp, or email.