Dec. 29 2006 10:16 AM

In recent years, inkjet printing has emerged as the dominant technology for variable printing in the mailing and addressing markets, with inkjet inks themselves taking on an especially central role. More than just a subcomponent in a complex printing system, inkjet inks are fundamental enablers for meeting the demanding printing requirements of commercial printers and addressing companies.


In this article, the role of inkjet inks will be explored, specifically in the context of these markets. First, a quick overview of inkjet ink development is provided, giving insights into the process of uncovering and responding to the myriad of technical and business requirements. Then, several key trends in the mailing and addressing markets are described. Finally, a couple of recent advances in inkjet inks are highlighted, with clear benefits.


The Realities of Inkjet Ink Development

There is a widespread belief held by some hardware manufacturers and end users that inkjet inks can just be modified at the last minute to make a system work properly in any application. That is simply not true, and it is not how successful ink development companies commercialize their products. Ink formulation requires a rigorous commercialization process and cannot be treated as an extension to cooking, where master chefs can just add a "pinch of this" or a "touch of that" as desired.


Inkjet ink formulation is a complex product development effort, requiring a broad range of systems expertise and competence. Ink-specific requirements, such as color or optical density, are only a small part of the overall demands that must be met by a "good" ink. It's not sufficient for ink chemists to know only about pigments and polymers or only about dyes and dispersants. They must also understand many of the internal and external system interfaces involved. What are the firing parameters of the printhead? What materials are used in the ink tubing? What are the surface characteristics of the substrates on which the ink will be printed? What post-printing application requirements are there, such as abrasion resistance or light fastness?


Additionally, there are many workflow and business requirements that affect the formulation of an inkjet ink. For example, end users of inkjet printers in the direct mail market often want inks that will dry instantaneously at very high line speeds, in order to maximize their shop's throughput. However, those same end users want to start up their inkjet printers with no maintenance delays after a weekend of routine downtime, and have them running dependably until the last piece has been printed. Although this may sound like two entirely independent requirements, it actually ends up being a very challenging task for the ink chemist: Create an ink that dries fast on the substrate, but does not dry out in the printhead.


Listening to the Needs of the Market

The addressing market has recently been faced with a continual bombardment of market and technology changes. Volumes are up, and competition is intense. For example, even though First Class single-piece mail has declined by almost 1.5 billion pieces in the past year, overall mail volume has increased by nearly four billion pieces, according to the U.S. Postal Service. This can be attributed in large part to bulk and other discount mailings, which received a boost with the recent adoption of do-not-call legislation.


As would be expected, everyone is looking to cash in on these higher volumes. Large commercial printers seeking new revenue sources are upgrading bindery and finishing operations and finding themselves going head-to-head with traditional mailing and fulfillment companies. Likewise, smaller mailers are now looking to move upstream and take on new business. Both types of firms must find ways to streamline current production and maximize throughput, if they are to exploit the new opportunities without having to make major investments in capacity.


Beyond making their operations leaner and more agile, mailers must also expand their product portfolio with differentiated offerings. It's no longer sufficient to just print on a standard offset-type substrate or a #10 envelope. Glossy coated papers, clear poly windows and protective poly bags are just some of the substrates that must be printable if mailers are going to grow their businesses beyond their current customer base.


Of course, the appearance and quality of the finished piece is still of paramount importance. To both the recipient and the print buyer, a mail piece must look appealing and inviting, generating interest at a minimum, and prompting a response if requested. The print buyer's marketing group, in particular, wants to make sure the print quality of the inkjet portion of the piece does not detract in any way from its overall quality.


These three convergent market requirements faster throughput, substrate variety, higher print quality combined with an increasingly intense focus on total operating costs, are placing major challenges on bulk mailers. Recent advances in inkjet ink development, especially in drop-on-demand (DOD) inks, are coming to the rescue, and helping mailers respond to this multi-faceted challenge.


Recent Advances in Inkjet Ink Technology UV-Curable Inks

The advent of UV-curable inkjet inks has been one of the most exciting and promising ink innovations in the mailing and addressing markets. Unlike solvent- and water-based inks which dry primarily through varying rates of evaporation or absorption, UV inks dry or "cure" when they are exposed to the appropriate ultraviolet lamp. The result is an inkjet ink that is durable and compatible with a broad range of substrates, including plastic cards, glossy mailpieces and poly wraps. UV-based systems have an added advantage, in that there is virtually no printer maintenance required. This allows time-pressed mailers to get their operations started in the morning in a matter of minutes, as opposed to the extensive start-up and maintenance routines for which continuous inkjet (CIJ) printers are most notorious.


One of the hurdles still facing UV inkjet inks is manufacturing costs. Whereas traditional UV inks have been around for many years and have already benefited from lower and lower component costs, UV inkjet inks are just in the early stages of their product lives. The result is relatively high costs for some raw materials, leading to a slightly elevated manufacturing cost for the ink itself. The good news is that many raw material suppliers are now creating components, such as monomers and photo initiators, specifically designed for incorporation in inkjet formulas. This is the first and most important step toward driving costs down. As these advances continue, UV inkjet inks and systems will become more and more pervasive.


Additionally, and most important to users of UV inkjet inks, is the fact that their total costs of ownership are still likely to be lower than other inks. UV inks can require lower amounts of fluids per address printed, plus have significantly lower costs of waste due to reduced maintenance requirements. At the end of the day, total operating costs for UV inks are extremely competitive with alternative technologies or ink types.


Thermal Inkjet Inks

Thermal inkjet technology (TIJ) has rapidly been adopted by both small mailers and large commercial printers alike, with HP-based systems gaining significant market share. Desktop-like ease of use, low initial investment costs and water-based inks have been the most appealing attributes of this technology. Small shops can enter the mailing business quite economically using TIJ-based systems, while larger firms are often considering TIJ in order to manage overflow business and capacity peaks in their plants. Although the unit costs of TIJ inks tend to be significantly higher than their solvent and UV counterparts, the market has determined that it is willing to incur a higher cost of ownership to obtain the benefits mentioned. ·


Unfortunately, adopters of TIJ's water-based inks have to endure certain performance limitations that can adversely affect their business. Most notably, TIJ inks dry slowly, if at all, on low- and non-porous substrates. This can be very restrictive given that many bulk mailpieces are constructed of high-gloss, low-porosity materials. Additionally, TIJ inks tend to provide limited color density and image durability on many substrates, further reducing their usefulness in many mailing applications.


To overcome these limitations, companies are bundling inkjet-receptive coatings with water-based inks, thus greatly extending the use of TIJ technology on a wider range of substrates, while vastly improving dry times. Additionally, new TIJ inks are beginning to emerge that are no longer purely water-based; these will shorten drying times and improve direct substrate adhesion, without sacrificing other performance criteria such as shelf life.


The Future of Inkjet Is Here

Business and technology challenges abound in the mailing and addressing markets, with increasing demands for "faster, better, cheaper" ratcheting up the competitive pressures on firms. Recent advances in inkjet inks can play a role in helping organizations respond to these critical demands. Selecting the correct ink type can have a profound effect on the ultimate success of a firm in the mailing and addressing arena by enabling new market opportunities through substrate flexibility, lowering total operational costs, reducing wasted materials and time and contributing to the delivery of high-quality products.


Similarly, this is a very exciting time for inkjet ink manufacturers to capitalize on the unmet needs of the market. Those best positioned to win the inkjet ink challenge will do so by following a rigorous process for product development: listening carefully to the needs of the market, addressing both technical and business requirements, applying a comprehensive systems development approach, leveraging their competencies across several ink types to commercialize innovative products, and exploiting their manufacturing capabilities to deliver high-quality inks on time, every time.


Sean Skelly is the director of product management at Jetrion.  Contact or