Commentary & Analysis
FREE: At Drupa, Progress in Press Control Technology Paced That of the Presses Themselves
No account of trends in offset lithography at drupa would be complete without a mention of press control systems:
By Patrick Henry
Published: May 26, 2004
No account of trends in offset lithography at drupa would be complete without a mention of press control systems: peripheral devices and software that automatically prepare presses for operation, monitor their performance and, when necessary, nudge them back into conformance with preset job parameters. Press manufacturers often furnish these systems as options or sub-components when they sell equipment, but other providers have weighed in with compatible, equally capable solutions of their own. The re-flowering of press technology at drupa was matched by corresponding developments in control systems from independent manufacturers, as we hope the following descriptions of products from three such providers will make clear.
Advanced Vision Technologies (AVT)
When AVT came to drupa 2000, it was as a vendor of an automatic defect detection system for web pressesa video monitoring accessory designed to catch spots, streaks, and other evidence of spoilage in the running web. This remains the Israeli company's core technology, but its drupa 2004 offerings included a much broader range of solutions for assuring quality control during press runs.
Lance Shumaker, president of AVT's U.S. corporate office in Atlanta, said that one of the most notable additions to the system was a function enabling it to compare color information from the print run with stored spectrophotometric data. Live, inline color monitoring, said Shumaker, is superior to spectrophotometer readings at the end of the run with numerous pulls of test sheetsa routine that he called a practice, but not a necessity that restrains productivity.
Shown for the first time at drupa, AVT's expanded solution uses an LCCD video camera to scan the running web and capture color information in RGB format. Proprietary software converts the RGB data into CIE L*a*b color values that can be continuously compared to the absolute CIE L*a*b values derived from a spectrophotometric reading of the sign-off proof. In this way, said Shumaker, the system keeps press operators apprised of color quality and sends them instant alerts whenever the color being printed deviates from the color they are striving to match.
Shumaker said that the system, which incorporates color measuring technology from X-Rite, can be installed on multiple presses and networked with PrintFlow Manager, an AVT product that makes it possible to monitor the color output of all networked presses simultaneously. He added that PrintVision/Jupiter, a new process control system for the color monitoring solution, has a simplified, more intuitive interface for easier operation.
Some aspects of AVT's core technology have not changed. The press-mounted defect detection units still use status lightsgreen for normal operation, and yellow and red for out-of-tolerance conditionsto alert crews to changes during the run. The system also flashes instantaneous alerts to the control console, enabling operators to deal with defects as soon as they occur. Shumaker said that as operators learn to rely on the system for a true picture of what the press is doing, they begin to abandon their habit of running at less than full speed for fear of printing problems that may not necessarily occur. By minimizing spoilage and encouraging operators to run at full speed, Shumaker said, the system can achieve payback within 12 months.
AVT has installed about 800 systems worldwide, according to Shumaker, on web equipment of all kinds ranging from 100" gravure presses narrow-web label presses. AVT has OEM agreements for its inspection systems with most press manufacturers and makers of rewinding equipment, he said.
To help pharmaceutical printers meet the stringent accuracy requirements of the FDA and other regulatory bodies, AVT offers PrintVision/Apollo, a solution that compares a master image, stored in a proprietary format, against printed output as it is taken up on the rewinder. Shumaker said that whenever Apollo detects a deviationwhich could be as small as a single broken letterit stops the rewinder to permit a physical inspection.
Similar to Apollo except for the fact that it works offline is AVT's ProoFit, a version-checking solution that uses PDF files like electronic overlays either to confirm that two documents are identical or to pinpoint the differences between them.
Launched at drupa for the package printing market was AVT's Prestige package, a set of control modules for central impression flexographic presses. The modules automatically regulate presetting and control for register, plate pressure, and runtime management for color.
Executives of this manufacturer of control systems for web offset presses said that the fact that the parent company is QuadGraphicsNorth America's fourth largest printerhasn't raised competitive Quadrophobia as a barrier to marketing QuadTech products to other printers. They said that QuadTech, chartered by QuadGraphics in 1979 to devise methods of reducing waste, introduced the world's first closed loop register control system, a technology that QuadGraphics went on to install on nearly all of its web offset equipment. QuadTech now markets a total of 55 products for process automation and quality control to web printers in 85 countries.
Randy Freeman, vice president of business development, said at a drupa media briefing that QuadTech's broad goal is to hasten the arrival of lights out printing with solutions designed to eliminate the ambiguities and the bottlenecks of print manufacturing. Soma Patel, technical manager for product development, noted that the annual installation of $1.6 billion worth of web offset equipment creates a market opportunity that QuadTech is ready and eager to cultivate.
In drupa's PrintCity (Hall 6), the company showed new and existing products for the publications, gravure, commercial web offset, newspaper, and package printing markets. The new products included:
- Data Central, a modular, JDF-enabled software product for enhanced productivity in newspaper and commercial web offset printing. The first two modules to be released control automated setup and press performance reporting.
- QuadTech Color Control System, which reads micro color bars at full press speed for real-time information about print quality factors such as CMYK ink densities, contrast, trap, and dot gain. A version developed with System Brunner provides automated tri-color and midtone gray balance control.
- Autotron Packaging 2600 Register Guidance System, enhanced to meet the requirements of the packaging and publication gravure markets with an expanded selection of miniature scanning heads and a low-contrast lock-on feature that enables the heads to work with very low-contrast marks encountered in the printing of packaging and decorative materials.
- Heliostat 300 Electrostatic Ink Assist, which uses carbon fiber brushes to electrostatically charge the impression roller of a gravure press. This is said to facilitate the transfer of ink to the paper, reducing speckling and dot skip.
Visitors to the upcoming Graph Expo in Chicago (Oct. 10-13) may want to make a point of calling on a new exhibitor from Bratislava in the Slovak RepublicPrintflow, which intends to stock its stand in McCormick Place with the same ink presetting and control systems that it displayed in Hall 4 at drupa. Vice president Bran Sulla said that the company, a former OEM partner to Czech press maker Adast, is small, employing only 10 people. But its reputation in Europe is what might be expected of a much bigger firm. For example, the May issue of German trade magazine Druck & Medien (Print & Media) named Printflow one of the 175 most important exhibitors at drupa among the more than 1,800 companies that displayed there.
According to Sulla, much of the favorable attention is being garnered by Printflow's Digital Ink Preset System, or DIPS, introduced two years ago at IPEX and now seeing its first installations in the U.S. DIPS is aimed, he said, at printers who want the benefits of digital press control without a CIP3/CIP4 workflow as a prerequisitea particularly attractive feature, according to Sulla, for printers operating older equipment.
DIPS essentially acts as a translator between the prepress workstation and the press, transforming prepress data into information for presetting ink keys and passing the information to the remote control unit of the press. This process, says Printflow, enables the precise presetting of ink fountains for less waste and a faster makeready.
DIPS, which Printflow says will work with any press that has a remote control console, consists of two parts: the DIPS converter and the DIPS box. The DIPS converter, a PC with proprietary software, generates ink presetting data from prepress files from the RIP. Besides calculating the percentage of coverage for each CMYK color zone, the converter also can generate what Printflow calls color digital blueprints with previews for form checking.
Sulla said that because DIPS digitally scans prepress data to obtain ink setting information, it can be used in lieu of a plate scanner for that purpose. He also pointed out that although the DIPS converter can process data in CIP3's print production format (PPF), it can also can handle prepress data as 1-bit TIFFs or in nearly any proprietary format that the plant may be using. This is an advantage, he said, in mixed environments where different workflow elements are present. It also provides a work-around alternative to systems that can only communicate via CIP4/CIP3.
The other component, the DIPS box, is installed next to the press console to translate data sent via Ethernet from the converter into instructions for the inking units on the press. When the job is ready to be printed, the image coverage data are converted to key preset values and is transferred to the press console to preset the fountains. Able to support several press lines at once by using multiple interfaces, the DIPS box also can be equipped with drives to accommodate cards, floppy disks, and other media specified by various press manufacturers for storing and recalling repeat jobs.
Sulla said that by the time of Graph Expo, Printflow will have three or four U.S. distributors for DIPS, which is in operation in a plant in Ohio and was scheduled for installation at a Colorado printer shortly after drupa.
Another focal point for Printflow at the Düsseldorf show was Printflow DC, a closed loop densitometric control system that Sulla described as a low-cost alternative to press manufacturers' OEM equipment performing the same function. The device enables a press to be linked to a Techkon RS 400 scanning densitometer with connections and software provided by Printflow. The system processes the densitometer's readings of color bars and calculates corresponding values for ink fountain adjustments, which it then sends to the press console. Printflow DC is compatible with consoles of new and older presses from MAN Roland, Heidelberg, and other manufacturers, according to Sulla, who estimated that 10 percent of all consoles can work with the solution.