What better use of printed graphics than for attention-getting posters and banners? The options are endless—from indoor advertising displays, to outdoor billboards, to vehicle and building wraps. The trick is to print them so that they still look good close up. Such large prints are typically the province of ink jet printers.
A few definitions might be useful. The term “wide format” usually refers to print media 24” to 99” wide. “Super wide” or “grand” format printing means anything over 100” wide. Although offset presses can be built in these large formats, today much of this printing is done on some type of ink jet system. The two leading technologies are thermal (or bubble) jet, employed initially by Canon and Hewlett Packard, and piezo-electric, which was developed and patented by Epson. Thermal ink jet applies heat to the ink reservoir, causing the ink to vaporize and create a bubble. The bubble pushes a drop of ink out of the nozzle. Piezo uses an electrical charge to vibrate a tiny crystal against the ink reservoir, and the vibration forces a drop of ink out of the nozzle.
In both types of systems, the technologies have evolved to the point that they can control the size of the drops of ink released in order to produce fine line and colour detail, as well as a broad spectrum of CMYK colours. Also, these drops of ink are so small, they’re almost microscopic. The printhead on a desktop bubble jet printer, for example, can incorporate 300 to 600 ink nozzles. A wide format ink jet printer’s printhead may have something in the neighborhood of 30,000, and all of them can fire simultaneously.
When wide format ink jet printers were introduced in the 1990s, they generally fell into two categories—dye or pigment—according to the type of ink used. Dyes completely dissolve in a water carrier and provide a continuous tone appearance. However, once printed, the images tend to fade quickly, and dye inks don’t adhere well to substrates such as vinyl, rigid plastic, or glass. Pigment inks are formulated with finely-ground powders to produce more intense colour than dyes, but the pigments have to be suspended in some type of liquid carrier for the jetting process and also for adhesion to a broad range of substrates. Whether pigments are suspended in a water-based or chemical solution, they never quite dissolve, but are absorbed into the substrate. Because of this, once printed, they hold their colour much longer, and the print film can be much more durable.
Pigment inks are the norm today, and they are further subdivided as to their solution—either aqueous (water-based), or solvent-based. The solvent inks can include different chemicals for use with a broad range substrates for both indoor and outdoor signage, banners, displays, point of purchase advertising displays, floor graphics, and billboards. The possibilities are almost endless.
Aqueous solvent inks work well for indoor signs and banners, displays and similar items, and are usually best for short-term displays. Though they last longer than dye inks, they will fade in sunlight and, unless coated or laminated, likely will not stand up well to rough handling or abrasion. By contrast, chemical solvent inks are formulated with resins to help the pigment stick to non-absorbent surfaces, such as the vinyls and synthetics typically used in outdoor and heavy-traffic applications. Outdoor solvent inks also are designed to withstand all kinds of weather conditions as well as providing an extra measure of rub- and scratch-resistance, and resistance to other solvents, such as cleaning fluids.
The above information explains why so many types of wide format ink jet printers are available, and serves as a tip for anyone looking to purchase a wide format printer. Ink jets are typically designed for optimal use with only one type of ink. The end use of the sign—indoor, outdoor, archival, photographic—dictates which model of ink jet to buy. But these are only the most basic issues to take into account.
Developments in solvent inks
When solvent inks are printed, most of the solvent evaporates, leaving primarily pigment, or colour, on the substrate. With aqueous inks, the solvent is water. In the case of chemical solvent inks, the evaporation process can emit VOCs (volatile organic chemicals) into the atmosphere. Most solvent ink jet systems must be operated in a well-ventilated production facility, which means installing exhaust systems. Health, environmental, and regulatory considerations have led manufacturers to develop inks that are described as “eco-solvents” or “mild solvents.” These are formulated with chemicals that are generally not harmful to humans, or give off a lower level of VOCs than the “true” or more “aggressive” solvent inks.
For Carl May, owner and president of True Colours Ltd., located in North Vancouver, B.C., the environmental impact of solvent inks is a significant issue. The company was established in 1991 as a prepress shop, but has come a long way from those beginnings. True Colours now serves Vancouver’s Lower Mainland with a range of services that includes producing high-quality digital graphics for discovery centres, trade show displays, limited edition print-making, signage, Web-based and short-run digital printing, contract proofing, and drum scanning. As the business has evolved and expanded, the one constant has been True Colours’ commitment to sustainability.
“We waited a long time to get an eco-solvent system for outdoor displays that could provide the level of quality we need,” May said. “Though eco-solvent printers were available, they were less than [we] desired in terms of image quality.”
True Colours installed a 64” wide Mutoh ValueJet 1604 eco-solvent printer in December 2006. The system employs piezo printhead technology and uses Mutoh’s mild solvent Eco-Ultra inks, designed for the durability and scratch-resistance required of outdoor applications. The ink is fast-drying, odorless, and produces images that can last up to three years outdoors without lamination.
“The Mutoh is more environmentally friendly than a pure solvent system,” May noted. “There are no harmful vapors from the inks and no VOCs. The printer doesn’t have to be vented in a special way, and even with venting, you still get VOC emissions.”
And the Mutoh 1604 doesn’t sacrifice quality for sustainability. Mutoh utilizes a patented print technology called I2 (pronounced I-squared), or Intelligent Interweave. Mutoh’s I2 technology increases the consistency of dot size and dot release during printing to improve the image. The ink is laid down in a microscopic sine wave pattern to eliminate the colour banding that can occur with ink jet printing.
“The print quality is the best I’ve seen in any outdoor device,” May said.
Mutoh’s ValueJet models are offered in widths of 54”, 64”, and 100”, accept a wide range of media, and offer print resolutions of 540, 720, and 1440 dpi. Print speed is up to 185 sq. ft./hr. The ValueJets will print on both rigid and flexible substrates, with weights an
d core sizes varying depending upon the specific model.
High-volume, super wide
Eclipse Imaging, in Burlington, Ont., has over 100 employees and specializes in out-of-home advertising, including 14’ x 48’ billboards, signage and advertising for bus shelters, retail displays, and point of purchase advertising. General Manager Rick Steele describes this variety of work as “anything that can be run on a 40” or larger press.” In fact, Eclipse has 40” and 77” Harris offset presses, and initially printed much of its large format work in volumes that could reach thousands of copies. With changes in market demand, Eclipse Imaging now employs wide format ink jet to produce shorter runs, and also to eliminate some of the costs associated with offset printing, such as platemaking and press downtime for changeovers and makereadies.
The company has been using wide format ink jet printers for several years and recently replaced an aging installation with two Hewlett Packard Scitex XL1500 super wide format printers. Though best known for its desktop ink jet printers and full line of wide format Designjets, over recent years HP has invested heavily in expanding its digital printing product line, including acquiring Scitex Vision in 2005. The buy has allowed HP to offer solvent ink jet systems for industrial production.
“Primarily we use those printers for billboards,” Steele said. “One HP is designated for the vinyls. We have a vinyl feeder attached to the printer and we run almost exclusively vinyl on that press. It runs pretty much around the clock, printing 14’ x 48’ billboards. The other HP we use for printing digital paper. That would be for shorter-run billboards that don’t have the quantity requirements for litho. If a customer wanted 85 to 90 paper billboards, we would run that on the HP XL1500. If they said they needed 120, we would probably run it on one of the Harris offset presses.”
“That’s the beauty of digital print,” he continued. “It gives you the ability to do multiple designs without changing plates and all the expense of lithographic printing. That’s how digital has changed the business of outdoor advertising. It has made it so much more flexible.”
The HP XL1500 super wide format printer can print images up to 16.4’ wide, at speeds up to 1333 sq. ft./hr. It’s an eight-colour system using piezo printheads and HP’s Supreme solvent pigment inks. Resolutions can go to 370 x 740 dpi, and the XL1500 can print on almost any medium in any thickness, from paper to flexible banner, to fabrics and even carpet.
Eclipse Imaging is moving even further into digital printing with the installation of an HP Turbojet 8500, a digital screen printer that uses UV inks.
“The Turbojet 8500 will be for signage—retail signage, transit signage, but not billboards,” Steele said. “It’s a totally different type of press, a drum press. The image size is quite a bit smaller than the XL1500. The maximum size is 1.5 x 1.8 meters, or 4.9’ x 5.9’. You can even do vehicle wraps with the Turbojet, for fleet printing, or P-O-P displays.” Steele mentioned another possible application as “hoarding construction,” which refers to panels that are raised around a construction site and often printed with advertising. These would be printed on Crezon, a coated plywood material about 0.5” thick.
The Turbojet has just been installed at Eclipse, but Steele is already anticipating its impact. “When the Turbojet is up and running, that will really change our business,” he said. “It will allow us to print shorter run jobs that would have ordinarily run litho. We’ll be able to move that work to digital, where our makeready time is 10 to 15 minutes instead of 2.5 hours, and the cost to run the equipment is less. That kind of completes the puzzle for us. Having the two XL1500s and the Turbojet provides a nice solution for our customers who desire shorter runs. They’ll be able to get both billboards and signage from Eclipse Imaging.”
UV ink jet
As with HP’s Turbojet 8500, other major manufacturers of wide format ink jet systems, including Agfa and Fujifilm, have been developing UV inks and wide format ink jet systems, primarily for signage and related applications. Ink jetted UV images must be cured under UV lamps after the image is laid down. UV ink chemistry is different from solvent inks, and the UV curing process, though it quickly dries the images, isn’t an evaporation process and doesn’t generate VOC emissions. The primary advantage of using UV inks is their eco-friendliness. Still UV inks can’t entirely replace the more aggressive solvent inks or the eco-solvents in terms of durability for long-term outdoor or other tough applications. UV inks also cost more than solvent inks, though manufacturers claim that the higher up front cost of UV inks is mitigated by their faster production time, as UV inks cure much faster than solvents dry. In addition, because UV inks form a thinner ink film, less ink is used in UV printing, so an ink cartridge goes a little farther.
Over the last two years, UV inks and UV ink jet printing systems have inspired more interest than anything else in the wide format display and sign segment. EFI-VUTEk may lead the pack in UV wide format ink jet printers with four models: the QS2000, QS3200r, PV200 and PV320. Widths range from 80” to 126.5”, and the number of colours these systems print varies with the different models. The UV ink jets are offered alongside EFI-VUTEk’s solvent product line, and two models that print using dye sublimation technology. VUTEk also provides its own line of mild solvent and UV-curable inks.
Last year in Montreal, Fujifilm launched the Acuity HD 2504, a UV flatbed printer with a zoned vacuum table, which can produce a maximum image size of 49.6” x 99.2”. The printer uses piezo UV ink jet printheads and can print at resolutions equivalent to 1,440 dpi and higher. At the same time, Fujifilm launched its Vybrant line of solvent wide format ink jet printers with models in three sizes: the Vybrant 1906 accepts media 76” wide; model 2606 prints media up to 102” wide; and the model 3606 goes to 130” wide. The Vybrants use Fuji’s Spectra Novajet printhead technology, and print at speeds up to 860 sq. ft./hr, with a Quality Mode production speed of more than 400 sq. ft./hr.
Agfa has long offered the Sherpa line of water-based dye ink jet printers primarily for proofing applications, not for signage, and also offers the Anapurna M and Anapurna XL wide format ink jet flatbed printers that utilize UV inks for producing items like posters, billboards, fleet graphics, P-O-P displays, exhibition panels, stage graphics, ad panels, and similar applications. The Anapurna M prints images up to 63” wide while the XL model goes to 98”.
The next big thing
The wide format signage industry has been named by some observers as the fastest-growing segment in the printing industry, even though tre
nds indicate that at the lower end (read smaller and lower-cost) of the market, sales of wide format ink jet systems may be declining. With so many applications in wide format signage, wide format printing systems, technologies, and markets continue to evolve. The wide format products available today are so numerous, and in some cases so specialized, that a printer really must assess production requirements according to the specific market the shop plans to serve. Increasingly, there is no “one-size-fits-all” wide format ink jet printer.
The next breakthrough in the wide format field—for just about any application—may already be on its way from HP. The company has begun promoting a new type of ink called latex ink, which it recently launched at the Scitex facility in Israel. Latex ink is described as being water-based, and it will work with HP’s thermal inkjet technology.
Watch drupa for more details on this and other expansions of the wide format horizon.