If you are thinking about investing in a wide format printer you should have a clear idea about the type of work you want it to produce, and this will be dictated by the type of inkjet ink that your printer of choice uses. Here for convenience is a quick guide to the four principal inkjet ink types and their application and use.
The most popular wide format ink type with sign makers is solvent because the inks are very hard wearing and provide a strong vibrant colour output and can be used on a wide range of uncoated medias. The machines that run solvent inks like to be run on a daily basis to ensure the inks remain free flowing
Solvent ink is highly suited to outdoor applications such as on banners or vinyls because it is so hard wearing. Some manufacturers will guarantee the outdoor life of prints (if produced correctly and on the right media) anywhere between 5 to 7 years before fading occurs, and this can also be extended by laminating the printed matter.
The printers that utilise solvent inks will typically have lower temperature pre and post heater platens to assist with the evaporation of the oil based carrier which will evaporate and leave only the pigment behind in the image on the media. This is why it is necessary to ‘out-gas’ solvent printed images for 24 hours after printing, and before any lamination can be applied. This de-gassing process is important to ensure that the oil based carrier has fully evaporated.
Solvent inks have a high VOC level and will most certainly need a venting system installed. As the ink is quite corrosive you will also find you need to keep the printer heads clean to ensure clogging and head damage does not occur.
One advantage of using solvent inks for vehicle wrapping applications is how much they can be stretched while under extreme handling/fitting conditions.
Finally, lamination comes highly recommended for any vehicle graphics applications. Even though these inks are the toughest type out there, they will won’t last if un-laminated when placed on a vehicle.
Eco Solvent inks
The name can be a bit misleading because the eco part is more along the lines of being slightly less aggressive than solvent.
Eco solvent inks still use an oil based carrier but without the VOC levels found in solvent inks, and while an eco-solvent printing machine will not necessarily need a venting system, I still recommend a well ventilated area for this type of kit.
Colours are just as rich and vibrant as with solvent inks, and there is a wide variety of additional colours available such as Light cyan - Light magenta - Grey - Orange & White. These additional colours are a great way to increase your colour gamut but the downside is you will have to spend more to ‘fill-up’ your machine.
As with the solvent inks gassing out remains a requirement before use and, again, for something as extreme as vehicle wrapping, the stretch of the ink is comparable to the solvent ink.
Due to the less aggressive nature of the eco-solvent inks, its toll on the machinery is reduced so maintenance is less of a worry. This still needs to be carried out at regular intervals, but the machine can be left switched off and unused for a day or so (this differs from manufacturer to manufacturer) without any harm being done, or clogging occurring.
The ink is not as hard wearing as its solvent cousin and can be affected easily by chemicals and abrasion quite easily, so lamination is always a requirement.
Eco-solvent inks require a specially coated range of materials. Almost every manufacturer and distributor can supply these materials/substrates so you would be hard pushed not to find the right kind for it.
It is worth noting that both solvent and eco solvent inks will 'thin' the substrate material out, especially self adhesive materials (depending on ink loading). This can affect the dimensional stability of the material in certain circumstances, but as long as the gassing out procedure has been carried out for the appropriate amount of time, the stability will level out.
As the name suggests this uses a polymer with a water based carrier to get the ink onto surface of the material. Once the ink has been put down a significant amount of heat is used to evaporate the water carrier and this uses a lot of energy, and some first generation latex machines still require three phase power to run them. Smaller next generation latex printers can now be run off a standard 13 amp plug.
The advantage of using latex inks is that prints are dry as soon as they are come off the machine and can be laminated immediately without the need for de-gassing. The inks have quite a stretch to them as well which makes them ideal for vehicle graphics and wrapping. However, I have found that the colour output of latex printing is not really suited to vehicle wrapping as it tends to lack depth and punch.
Another bonus of latex ink is that it sits 'on' the surface of the material and, unlike solvent or eco-solvent inks, does not embed itself into the material. Theoretically speaking this means there will be more materials available for you to use, but the amount of heat required for curing may upset the dimensional stability of some of them.
The maintenance of a latex machine is lower due to the low corrosive nature of the inks.
UV inks and UV printers are great for producing rigid media work and usually print at a high speed with very good image quality onto a huge range of materials.
The range of printers that run UV ink is vast, from small desktop flat beds for promotional items, roll fed printers for POS/POP usage, wide format flat beds for direct to media printing and hybrid machines that can handle both rigid and roll fed media.
There are many advantages to UV, particularly with modern LED printers. The inks are cured via UV once put down and are dry immediately. The colour gamut is comparable with solvent inks, and lamination is not required on most outputs. The VOC levels are also low, so ventilating the kit is not a requirement, but UV inks are generally more expensive. However, one thing the ink is not good at is stretching, so vehicle wrap graphics are not possible with this ink type.
In summary, don’t buy your first wide format printing machine until after you have identified what type of output you want to produce. Once you have identified what sort of applications you are looking to produce, the printer will pretty much choose itself.