How to keep white DTF ink from clogging: agitation, circulation and storage

Why white settles

White DTF ink is titanium dioxide (TiO₂) in a water and glycol base. The particles are dense, and they have to be fairly large to give opacity. Suppliers say white starts settling within hours and turns paste-like after two or three days without movement, while colour inks stay mixed for days. A cold room makes it settle faster. Settling does not stop at the bottle. White that sat in the dampers overnight is still settled after you shake the bottle. That is why the routine has several steps.

Agitating the right way

• Bottles: turn them end over end, gently, for 30–60 s before you refill and before the first print of the day. A sealed new bottle can take a firmer shake.
• Tanks and cartridges already connected to the head: rock them slowly for about 30 s. Do not shake hard. Bubbles in the system cause streaks and pinholes.
• Wait about a minute after agitating so bubbles rise before you print.
• In long runs, agitate again during the day. Sources range from every 30–60 minutes to every 2–3 hours; heavy white coverage needs the shorter end.
• Agitate once a day even if you have a stirrer or circulation. Pigment at the bottom of a bottle does not lift by itself.

Stirrers and circulation

Many kits add a stirrer motor in the white tank or a pump that loops white from the tank to the damper and back. They keep the lines and dampers moving. They do not clean the cap and they do not replace your daily agitation.

• Timers work well. Published schedules: 5–10 minutes before work, then 2–3 minutes every 2–4 hours of work, and 15–20 minutes before a long shutdown.
• Sources disagree on running it non-stop. A timer or smart plug is the safer choice and wears the motor less.
• The stirrer can run with the printer off, as long as the head is parked on a clean, wet cap.
• Never run a circulation pump onto a head that is failing its nozzle check. Pressure builds in the white damper and it can burst, flooding the head board with ink.

“Non-settling” white inks

Some inks use coated pigment and stronger dispersants. They still settle, but into a soft layer that remixes easily instead of a hard cake. They lower the risk. They do not remove the daily routine, and no independent test data backs the marketing claims.

Room conditions

• Humidity 40–60 %, ideally about 50 %. Dry air dries ink on the nozzle plate; above 60 % film and powder pick up moisture.
• Temperature about 20–26 °C. Cold thickens white and speeds settling; above 30 °C ink can dry early in the dampers and head.

Storage and shelf life

• Unopened: usually 12–18 months from manufacture. Opened: use within about 6 months. Check the date before you blame the head; old white thickens.
• Store at 15–25 °C. Some labels allow a wider range; the narrow one is safe for any brand. Never let it freeze: freezing can separate the pigment for good.
• Keep bottles sealed, out of light, in a ventilated place. Store refill cartridges for the XP-15000 lying flat.
• Do not mix brands of white in one system unless the maker says they are compatible.
• Keep every tank above one third full.

Keep-alive in ZoroPrint

Switch on Expert mode, then in the Printer tab → Maintenance tick “Keep white ink moving while idle”. After the hours you choose with no print (2–72, default 8), the app prints a 60 × 3 mm white strip for each white channel, about 0.02 ml of white per strip. It needs the app open, the printer on and film loaded. A strip only moves the white the nozzles fire: it does not stir the bottle or clean the cap.