When we remind ourselves about the early days of wide-format digital technology one thing we’ll all acknowledge is that we were pretty limited by the inks and materials available, and how well the machines of the day could handle them. If the results came out well on our chosen substrate, then we were pretty satisfied; if the end product wasn’t fit for purpose, then the ink tended to get blamed.
Wide-format digital print is all about ink and its inherent behaviour during the processes we expect it to endure. For machine manufacturers, it’s the element in their equipment that actually proves the unit is as good as it claims to be. Ink also represents the part of the printing process which tends to play a major role in carrying the responsibility for quality even though it is dependent on machinery and technology for being transferred from cartridge or bottle through to the printhead nozzles and jetted onto the material beneath.
Not surprisingly, ink tends to be the component that is subjected to the greatest criticism by print service providers and display producers in most parts of the world. We are all colour critical but we are also governed by other factors, such as price, performance and adhesion. We expect our formulations to do their jobs flawlessly, with maximum coverage and minimum overall deposit. And we curse it when it smells, blocks our printheads and leaks from its container or cartridge.
Today’s choices in ink formulations have move rapidly onwards from earlier aqueous formulations, through solvent-based chemistries to UV-curable products. These are complemented by specialist options such as those needed for textiles and glass. We acknowledge that it is key to our standards of production output and, hence, we demand unforgiving and versatile performance when combined with new and existing end materials so that display producers can evolve into new markets and applications as well as continuing down their tried and trusted routes.
The reputation of ink lies heavy on its manufacturer’s shoulders. In the early days, most printer developers readily admitted they didn’t make their own ink, and many still don’t. However, as a means of retaining control over machine performance and for maintaining a permanent link with end users, ink justifiably is a valuable consumable for printer suppliers. Machine manufacturers recognise this and, for every single piece of equipment sold, the intention is that repeat business comes from the continued purchase of ink.
As a convenient and essential chemistry that results from mixing pigments with carriers, ink is the stuff which really is crucial because it’s the element of an end job to which the human eye is instantly attracted. Its quality, accuracy and coverage combine to become the make or break element and its colour renditions are the combination of chemistry and the instructions handed out by the software used to drive the printer.
There’s another important factor responsible users and, even, entire countries take into account when considering ink as part of a process. Formulations can be pretty unpleasant. We are all aware of the potential carcinogenic properties and hazardous chemicals contained in some of the full-strength solvent-based options.
Users should also understand that UV-curable ink, in its liquid state, is very nasty stuff indeed and needs to be treated with the greatest respect. Likewise, it is the law here that inks must be supplied with a material data safety sheet (MSDS) that lists the hazardous components incorporated with instructions on how these should be handled in case of accident or spillage.
Ink formulations suffer from harsh criteria where printer users want fantastic colour consistently, products that have a long shelf life and flow flawlessly through their machines day in and day out. Nonetheless, there is often a curious reluctance to accept its litre costs. But ink is a confusing element within the wide-format industry and many people can’t understand why it can’t have a cost which equates to the same price of milk or bottled water. We see increasingly third-party, or after-market, options all promising to be cheaper and perform as well as OEM products. This confusion is exacerbated by the thought that, despite the label the ink appears to be carrying, it could well come out of the same production facility where manufacturers’ own formulations are generated.
Additionally, the combination of chemistries could easily involve different specialist companies being responsible for each of the components. These only get given a recognised manufacturer’s name once all the elements have been put together to become the product we know as ink. All the end user really wants is a consistently reliable formulation which literally does what it says on the tin and enables the efficient output of inkjet applications onto various different materials.
Ink chemistries cannot be developed overnight because there are too many imponderables that need to brought into play before a formulation can come to market successfully. Safety is a key factor, of course, as is the way the end product behaves in different climates and environments, including reacting properly with temperature and humidity variations. It needs to remain in a liquid state until we want it to dry or cure, and it has to behave itself within the complexities of printing machines’ inner workings, pumps and, of course, printhead nozzles. And it must be controllable but sufficiently flexible to be able to produce the desired droplet sizes in both greyscale and binary heads.
Once its relationship with the print unit has been established, ink has to meet the necessary criteria to adhere properly and provide the right appearance on the end material. These days, this can vary from low-end papers through the full gamut to premium rigid and flexible substrates. This performance is vital to its success; other factors, such as durability and flexibility on the substrate’s surfaces plus the ability to maintain its adhesion once contour cut, also need to be taken into account.
As the constant requirement within the print process, there is the additional consideration that manufacturers have to take on board. The constant developments and improvements in technologies, and introduction of new machines and revised printheads and jetting capabilities, don’t necessarily mean that users will cast their existing equipment aside just because it’s no longer a current model.
Currently there are vast numbers of older systems which have long been superseded in development terms that are still in use today, beavering away to produce satisfactory results. Some of these are no longer supported by their original manufacturers and, thus, are obsolete through no fault of their own. Yet they still function perfectly well and, as a result, their owners expect to be able to obtain compatible ink to keep these printers running.
Maintaining stocks of inks for old systems whilst keeping up with new developments also puts pressure on manufacturers in terms of production and logistics. New generations of formulations with claimed added benefits still need to compete with the high volume requirements of older chemistries; thus the supply channel is expected to deliver, no matter the vintage of the printer in question.
Overall, ink represents far more than its end appearance of being a coloured liquid in a cartridge or container. It is the key repeat purchase for every display producer and, of course, it is the printer user whose responsibility and choice rests on staying with the original manufacturer or venturing into the often unknown territory of switching to a third-party supplier.
Contention will always be rife as the arguments for and against changing or staying with original ink suppliers continue. Some display producers don’t want to move to an after-market channel for fear of blowing a hole in their warranties; others are more gung ho about making the decision to take the third-party route.
Like so many elements in life, all ink manufacturers claim they are equal; but some are more equal than others. This dystopian allegory is misquoted deliberately here but, nonetheless, it is true. Some print companies rue the day they moved to a third-party ink supplier whilst others applaud the fact that they made the decision, claiming that better colour and lower costs have resulted in huge savings.
Inkjet technologies will continue to move forward to encompass new production areas and techniques as print carries on down the road of development. Revisions to ink chemistries no doubt will also continue to emerge, and it is up to the individual and his printing machine as to the long-term route chosen for his ink supply.