Recirculation is the single feature that separates a modern industrial printhead from the generation before it, and it is also the specification most often quoted without being understood. This article explains what recirculation physically does inside the head, which problems it solves on a real press, and when a simpler non-recirculating head is the better — and cheaper — choice.
What recirculation actually is
In a non-recirculating head, ink enters the channel, is ejected when the actuator fires, and the only movement through the head is caused by jetting. When the head is idle or firing lightly, the ink in the channels is effectively stationary.
A recirculating head adds a continuous flow: ink is pumped through the head, past the back of every nozzle, and back out to the ink system, whether or not the head is printing. The mechanisms differ between manufacturers — Xaar calls it TF Technology®, Fujifilm Dimatix calls it RediJet®, and SEIKO writes it into the model name itself, where RC on the RC1536 stands for recirculation — but the principle is the same.
One important nuance: not all recirculation runs all the time. The Xaar 502 GS15 O supports TF Technology in Pulsed mode — ink is recirculated while the head is not jetting, which clears air bubbles and lets nozzles self-recover at minimum complexity and cost. The 502 GS15 OR adds High Flow recirculation for continuous high-speed flow past the nozzles, for glazes and inks that need it.
The five problems recirculation solves
1. Sedimentation. High-pigment inks settle. Ceramic inks, white inks and metallic or effect inks carry heavy particles that fall out of suspension when the fluid is still. Continuous flow keeps pigment moving, which is why recirculating heads run these inks for hours without the drop-volume drift that plagues fixed heads.
2. Trapped air. Air bubbles in a channel produce a missing jet that does not recover on its own. Flow past the nozzles carries bubbles out of the head instead of parking them at the actuator.
3. Nozzle dry-out on idle. The ink at a non-firing nozzle thickens. Recirculation keeps fresh fluid at the nozzle, which extends the interval before a maintenance cycle is needed.
4. Long-run consistency. Because every nozzle sees the same flow and the same temperature, drop formation stays uniform from the first nozzle to the last. This is what allows several heads to sit side by side in one bar with minimal variation between them.
5. Difficult fluids. Very high viscosity fluids and heavily loaded glazes cannot be jetted reliably by a head that only moves ink when it fires. Xaar’s Ultra High Viscosity Technology, for example, extends jetting to fluids up to 100 cP on the Xaar 2002 platform — work that is only possible because the ink path is being actively driven.
What it costs you
Recirculation is not free, and it is not always worth it:
- An ink system, not just a head. Recirculating heads need pumps, pressure control, return lines and filtration designed for continuous flow. Retrofitting a machine that was built for a static supply is a substantial project, not a head swap.
- More places to go wrong. Flow rate, pressure balance and filter condition all become part of the maintenance schedule.
- Higher unit cost. A recirculating head is a more complex assembly than a fixed-geometry head of the same nozzle count.
- It only helps if you need it. If you run standard-viscosity, low-pigment inks on a machine with good capping and a disciplined purge routine, a fixed head will produce the same output for less money.
Which heads recirculate — a quick reference
| Platform | Recirculation | Notes |
|---|---|---|
| XAAR 1003 | TF Technology® | Keeps pigmented oil-based ceramic ink in suspension through long runs |
| XAAR 2001+ / 2002 | TF Technology® | 2002 adds SureFlow™ self-cleaning and jets to 100 cP |
| XAAR 502 | TF in Pulsed mode (GS15 O) High Flow TF (GS15 OR) | Choose OR where the ink or glaze needs continuous high-speed flow |
| SEIKO RC1536 / RCE2560 | Nozzle-level recirculation | RCE2560 adds dual inlets and outlets |
| Fujifilm Dimatix SG1024 | RediJet® | Continuous recirculation past the nozzles |
| Fujifilm Dimatix SG600 | RediJet® dual-port | Fast priming, minimal ink waste |
| Fujifilm Dimatix PQ-512 | Dual-ported modules | Each 256-jet module primes, flushes and recirculates independently |
| TOSHIBA CF1XL / CF1L | Per-channel recirculation | Ink recirculates through every channel past the nozzles |
| SEIKO SPT510 / SPT1020 / SPT1024GS | None | Fixed-geometry heads — simpler ink system, no internal flow |
| SEIKO 508GS | None | Built-in damper and non-wetting nozzle plate instead |
Non-recirculating heads: where they still win
The fixed-geometry generation did not disappear for a reason. The SEIKO SPT510 and SPT1020 are still among the most widely fitted heads in grand-format printing, running oil-based, solvent and UV inks with a clog resistance that made them an industry standard. A fixed 35 pL or 50 pL drop is enough for exterior banners, backlit signage and vehicle wraps, where ink density matters more than tonal finesse.
They are also genuinely easier to live with. There is no circulation loop to balance, no return line to filter, and a head can be replaced without rethinking the ink system. If your production is fundamentally about opaque laydown rather than gradient smoothness, a fixed-drop head remains the pragmatic choice.
How to decide
- What inks do you run? High-pigment, white, metallic or effect inks point to recirculation. Standard solvent or UV process colours do not.
- How long does the head sit idle? Stop-start production and overnight gaps favour recirculation, or at minimum a head with a tickling function like the SPT1020.
- What is the machine built for? This is usually the deciding factor. A recirculating head in a machine without a circulation loop will not work.
- What is the failure costing you? If a maintenance purge is a normal part of every shift, recirculation pays for itself. If not, it may not.
Not sure which side of the line your machine sits on? Send us the printer model and the ink you run via the contact form, and we will tell you what the bar was designed to take — and which heads we hold in stock for it across the full printhead range.
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