Digital printing involves any reproduction process that does not use a replaceable image carrier (such as a plate). Digital printing can use any method that places spots of colored particles on substrates, with toner or inkjet being most common. Of late, new inkjet devices and developments are causing many to project an inkjet future.

Inkjet technology is either thermal (heat makes a bubble), piezo (pressure makes a bubble) or continuous (pressure makes a flow). Inkjet printing can be sheetfed, roll-fed, flatbed, or combinations. It can use inks that are aqueous (water-based), solvent-based, eco-solvent and UV. Quality levels have been more than acceptable for signage and industrial applications, but not for commercial work. Speeds generally have been slow. Until now, there have been only a few players in the high-speed, higher-quality segment.

In the last year, however, HP, Kodak, Memjet, FFEI, and other manufacturers have revealed (if not announced) new developments. Claims of speeds over 500 fpm and over 600 dpi have aroused interest. Considering that toner-based digital printing dominates, why is inkjet generating interest?

• Less complexity. Almost everything about inkjet is in the heads. There are less electronics, heating units and drums/belts to deal with.
• Potential for spot colors. The single impediment to toner printing is its inability to print all the Pantone (and now Goe) colors. Only one liquid toner printer can handle spot colors. In discussion after discussion with print buyers, their company brand colors are important.
• Like toner, there is no makeready, so there is instant job changeover with no waste.
• Inkjet is scalable from the desktop to the plant floor. Thus, proofers could use exactly the same technology to allow for proofing in customer offices.
• Larger toner-based systems have high power requirements with equally larger power units and severe environmental requirements. Inkjet requires much less of all that.

This does not mean inkjet is perfect. There still are issues with substrate availability and head width. A lot will depend on ink formulations in terms of substrates and quality. Heads must be self-recovering to avoid clogs and missed spots.

The first application will be the so-called transpromo market for bills and statements that incorporate ads. Next, retail promotions that incorporate coupons. After that, the market could affect commercial printing if coated stocks and color reproduction are sufficient.

The 2008 Drupa event will showcase at least 10 high-speed, high-quality inkjet systems. A new market will be born and it will have an affect on offset litho volumes.

Frank Romano is a professor emeritus at Rochester Institute of Technology. Contact him at fxrppr@rit.edu.