This month Colin Marsh, managing director of Resolute DTG, explains the importance of storing your DTG and UV inks correctly.
Some inks, especially water-based non-solvent inks, used in most DTG printers are susceptible to changes in temperature and long periods of stationery time. White inks containing TI02 (titanium dioxide) will suffer serious damage and performance issues if not stored correctly.
Keeping your digital inks in the right environment is a very important factor, if you carry any amount of stock that sits on your shelves for any more than a couple of days and don’t look after it correctly you could be risking an expensive product going to waste. Temperature plays a big part in the shelf life of your inks just the same as in dairy products like milk.
While some anti-bacterial agents are used in the production of water-based inks these will not increase or extend your ink’s natural shelf life if kept at the wrong temperature. Ideally ink should be kept between 10⁰C and 18⁰C, this is not always possible if you do not have an air conditioned room for storage. Making sure your inks remain at a constant temperature, never below 5⁰C or above 22⁰C is a good step towards good storage.
Never put your ink in the fridge or freezer to cool them down as quick drops in temperature will cause condensation in the bottle or cartridge, this will accelerate a split between pigment and vehicle solution. Dropout or separation as it is more commonly called can be easily avoided and preserve the dispersion in its original state with a simple agitation routine. On an industrial scale 20 litre drums and in some cases 1,000 litre ton cubes of ink are automatically rotated by motorised systems 24 hours a day seven days a week.
Keeping bottled white ink in good condition
In some ways bottled ink can be easier to maintain in a good dispersion as the container lends itself to slow rolling which is a natural form of agitation. Shaking a bottle vigorously after it has been sat idle for a couple of weeks will mix things up again but not in the way the original dispersion is made during manufacture.
The best way to keep your bottled ink in good condition is to move it back and forth in a 180⁰ motion for a couple of minutes a day, and store it on its side. This gives a greater surface area for pigment to sit in a thinner layer than on the bottom of the bottle making it easier to move around. This should be enough to keep things dispersed nicely.
Too much shaking will gas the ink up resulting in problems when printing. Tiny air bubbles form when some inks are shaken and these are so small they will not rise fully to the top and can remain in the ink causing problems when jetted through the print head. If you do have to shake your ink vigorously make sure you give it at least 30 minutes to stand before trying to print with it.
Keeping white ink in cartridges in good condition
Cartridges can contain a complex range of chambers and tubes depending on the pressure system or circulation system used in the printer they are designed for. These can be traps for pigment if not kept in good condition.
Once the pigment splits out and the water migrates to another part of the cartridge it can become impossible to get the ink back anywhere near its original dispersion state. Ink in cartridges is however can be very easy to maintain. Rocking from left to right 180⁰ for a couple of minutes a day is normally enough to keep it in a good dispersion state. This will avoid the ink splitting and pigment clogging up certain areas