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Digital Platemaking Without the Chemistry

Jul 1, 2005 12:00 AM


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Since the advent of thermal computer-to-plate (CTP) technology about 10 years ago, the industry has looked for a platemaking system that is trouble free and more sensitive to the environment. The missing link has long been the digital plate. Today, however, printers are seeing the introduction of a variety of new technologies that fulfill the promise of chemistry-free operations in the plant.

From ablative to switchable polymer, to the newest ThermoFuse technology from Agfa’s Graphic Systems Div., these new chemistry-free plates can eliminate process variables throughout the production process. Besides being friendlier to the environment, a chemical-free process has been shown to yield more stable, predictable results, with fewer processing parameters (speed, temperature, chemistry condition) to maintain and control.

In addition, there are cost savings inherent in the chemistry-free process. Printers no longer have to purchase chemistry, invest money in maintenance or contract with various services to remove hazardous waste. The elimination of extra steps keeps the shop clean and simplifies workflow.

No Hassles
Faced with many technology choices when switching from a film-based workflow to CTP, printers often are confused when making buying decisions. Identifying specific goals can help. Spotlight Graphics (Sarasota, FL), for example, wanted to improve quality and consistency while simplifying workflow. "When we made the switch to CTP," says prepress manager Chad Lynn, "we wanted to eliminate chemicals from the workflow. We didn’t want the hassle and cost of disposing waste chemicals."

As a result, Spotlight Graphics installed the :Azura chemistry-free plate system with Agfa’s Xcalibur45 thermal CTP unit. "With Agfa’s :Azura, platemaking is simple, clean and completed in fewer steps," Lynn notes.

Unlike conventional thermal platemaking, :Azura doesn’t need to be processed chemically to produce a lithographic image. Imaged :Azura plates only require a clean-out or gumming step to remove the non-image areas. Spotlight Graphics now uses just five liters of water-based gum each month. This saves on chemical and disposal costs.

According to Lynn, the chemical-free processing approach contributes to a more consistent plate, as there are no variables that need monitoring, such as prewash, preheat, chemical composition, temperature and processing speed. "Now the entire system can be controlled by just one operator," says Lynn.

Helping the Bottom Line
Because :Azura eliminates water and developer from the CTP process, the system can be environmentally sensitive and beneficial to the printer’s bottom line. For example, with :Azura, a typical printer using four-up CTP would use only a small container of gum per month, vs. traditional CTP systems that use thousands of gallons of water, developer and finisher. This affords users potentially thousands of dollars in annual savings. Golden Circle Graphics, a 20-employee printer in Jackson, TN, uses Agfa’s :Azura plates on its Creo eight-up Trendsetter with Brisque workflow. "We ran a linearization test to create a tone reproduction curve and we were ready to go," says Joel Maners, one of the partners operating Golden Circle.

Prior to adoption of the :Azura plate system, Golden Circle used various other plates, some of which had to be prebaked or undergo a postbake process. "With :Azura, there was neither pre- nor postbaking involved," says Maners, "resulting in time and electricity savings for the company."

According to Maners, it takes about six minutes per plate from the start of the process to press. "With the old plate," he explains, "it took about 30 minutes to make one plate and an hour to make a set of plates. We were using one oven for both pre- and postbaking. If we added up all the time it took to get the oven the right temperature for each procedure, to run one plate through the prebake and postbake processes, it was about 30 minutes. That’s just too long. With :Azura we are doing it in one-tenth the time."

At Golden Circle, three points were critical: saving money (no chemistry to buy), saving time (no chemical processing) and maintaining high quality.

"What drove us to :Azura was the cost of the chemistry, which was through the roof," says Maners. "We were spending $400 each week on chemistry alone. The solution was to take away the chemistry and lower the cost."

Quality in the Pressroom
Regardless of the benefits to the bottom line, printers can’t afford to sacrifice quality in the pressroom. In fact, quality is all-important in commercial printing operations. "What’s the point of doing something if you can’t do it well?" asks Maners of Golden Circle. ":Azura looks extremely good. We can provide our customers an excellent quality print."

At Spotlight Graphics, Lynn says the :Azura system produces "extremely high-quality results on demanding projects, holding 2-98 percent dots on plate." And the aluminum base allows the plate to act similarly to a conventional plate on press.

"The lithographic performance of this plate is really unbelievable," Lynn reports. "It has even held up to our longest press runs, which are well over 100,000 impressions, without wavering in quality."

Maners agrees. "We get excellent results from the :Azura plate using 175-lpi conventional screening. It is stable on press and the ink/water balance holds very well."

Because :Azura prints from a grained and anodized aluminum substrate, it provides good lithographic properties and a wide dampening latitude. And, because it is gummed before going to press, use of the plate reduces fingerprints and sensitivity, and allows extremely fast roll-up.

For those printers looking for a trouble-free, environmentally friendly platemaking system that delivers high quality on press, :Azura is targeted at four- and eight-up applications in low- to medium-volume commercial printing operations.

More information on :Azura chemistry-free digital thermal plate system is available from Agfa, 100 Challenger Rd., Ridgefield Park, NJ 07660-2199. Contact Marc Jacques at 800-540-2432, ext. 4848, or by e-mail at marc.jacques@agfa.com; or go online at www.agfa.com/en/gs/products_ services/all_products/azura.jsp to receive more details on :Azura and Agfa’s computer-to-plate solutions.

Agfa’s Graphic Systems also offers a full range of systems to the graphic arts industry, including inkjet proofing, workflow solutions, newspaper and packaging systems, as well as digital inkjet presses. For more details, visit www.agfa.com or contact your local Agfa representative.



How :Azura works
Based on a standard electrochemically grained and anodized aluminum base, :Azura plates are coated with a single-layer solution containing ink-accepting thermofusable particles that are small enough to deliver very sharp highlight reproduction. During the exposure on standard 830 nm thermal platesetters, the coating absorbs the heat in the image areas. This heat causes the thermofusable particles to fuse to each other and bond firmly to the aluminum substrate. The particles become a solid ink-accepting image, suitable for runs up to 100,000.

Non-imaged areas can be removed by washing them away with gum in the :C85 cleaning unit. At the same time, the gum protects the hydrophilic aluminum substrate from oxidation. The plates now are ready for the press where they print directly from the aluminum substrate, providing excellent lithographic latitude.

:Azura works with existing press chemistry. There is no need to change inks, fountain solution or plate cleaners. The aluminum base ensures fast ink roll-up and consistent ink/water balance.

Agfa’s ThermoFuse non-ablative technology was first introduced in 2000 on the :Thermolite plate for on-press imaging. Today, :Thermolite is in use on more than 100 direct imaging presses. ThermoFuse also is used on the :Azura plate, which can be imaged by any thermal platesetter at 830 nm.