Substrates
The mix of substrates for the new printer is another important consideration. A sign shop may plan to print directly onto flexible media and/or onto rigid materials; its choice in this regard will help narrow the search for the best printing platform.
It is also important to factor in both the ‘buy’ and ‘sell’ prices of substrates that will be run through the printer, with an eye on leveraging higher profit margins by minimizing material costs. With ultraviolet-curing (UV-curing) printers, for example, a sign shop can use non-coated substrates, which generally cost less than coated materials, thus allowing it to widen its opportunity for profit. And waste should be taken into account, with consideration given to the amount of ‘extra’ material a sign shop may normally expect to need and the relative costs of the substrates that shop can source for its printer.
Substrate weight might also be an issue, particularly if wide-format graphics will be shipped to clients who are seeking to reduce their freight costs. Light-emitting diode-based (LED-based) UV-curing printers can use thinner, lighter, heat-sensitive materials, for example, which can save on shipping costs. (The LEDs also require less energy than traditional UV lamps, yielding further savings in terms of operational costs.) In addition to financial advantages, there is also the environmental advantage of reducing the carbon footprint associated with shipping.
For that matter, the ability with UV-LEDs to print on heat-sensitive materials opens the door to working with a broader variety of inexpensive films and boards that would otherwise warp or buckle during printing. So, there can be savings above and beyond those associated with uncoated substrates for UV-curing printers.
Adding new wide-format digital inkjet printers represents a significant investment that must be carefully considered beforehand.
Inks
Ink prices should be considered in terms of square feet, rather than litres, because coverage levels on the substrate can significantly affect ongoing costs. The price per bottle will not tell the whole story in terms of profitability per print.
The type of ink used—durable aqueous ‘latex,’ solvent-based or UV-curable—will have an impact in terms of consumption, print production time, graphic durability, application range and environmental sustainability.
UV-curable inks, for example, are not only compatible with a wide range of flexible and rigid substrates, but have also become popular in the sign industry because they cure or ‘set’ quickly, yielding dry graphics that are immediately ready to move onto the next step in the production process; turnaround times are a major issue for many customers. UV inks offer environmental advantages over the solvent-based inks of the past, which contained noxious volatile organic compounds (VOCs) and required ventilation systems.
Many other inks require heating or greater drying time to achieve a proper cure, which entails special equipment and, thus, extra power consumption. And some inks are not water-resistant, so they will require an overcoat or lamination if the finished graphics are intended for outdoor installation.
That said, UV inks are not the best answer for every application, so it is important for signmakers to do their homework first, learning about how the type of ink selected will affect their scope of applications.
Another consideration that has become significant in wide-format printing in recent years is white ink. When a sign shop can print layers of white, it can output graphics on a broader array of substrates, including dark and transparent materials, which increases the variety of applications it can offer to customers. White ink is often required for window clings, backlit graphics, architectural features, packaging and prototypes, many of which can entail higher profit margins for the shop than other applications.
Printheads
The choice of inkjet printhead technology will also have an impact on ink consumption and quality of output.
Today’s piezoelectric drop-on-demand (DoD) inkjet technologies comprise three primary types of printheads:
- Binary—A single drop size is ejected from the printhead. This type of printhead can simulate greyscale effects with multiple passes but, in doing so, will consume more ink.
- Variable-drop—Different sizes of drops can be produced, but only one size per graphic, as this type of printhead is not capable of dynamic drop-volume changes within the same image.
- Variable-drop greyscale—Different sizes of drops can be ejected from the printhead within the same graphic, making it easier to produce near-photographic image quality.
