INSPECTION/COLOR CONTROL SYSTEMS -- Guarding the Web

BY CHRIS BAUER

Keeping a watchful eye on quality web offset press production has never been easier. With the influx of digital equipment for web inspection and closed-loop color control systems, accuracy, reliability and speed have all taken big steps forward.

"The primary influence has been the availability of high-resolution digital cameras versus traditional analog cameras, which provide printers with a more accurate image of their print quality," explains John Woolley, vice president of sales and marketing for PC Industries, of Gurnee, IL.

"The other trend is the availability of powerful, low cost computers to analyze printing defects. The bottom line is that web inspection system manufacturers that take advantage of the technology trends can provide higher performance at a fraction of the cost of older technology."

Technology Challenges

Virtually all control systems built today are computerized, adds Manny Patel, of Windsor, NJ-based Innolutions Inc. Since computer and microprocessor technology is a rapidly changing field, keeping up with this technology can be a challenge, he admits.

"Individual components and technologies become obsolete and unavailable literally overnight, and a manufacturer can be left without a product if care is not exercised in the design of controls," Patel warns. "We design our computerized controls to be platform independent, and to run on industry standard hardware. In this way we can always provide the highest performance and the lowest cost as technologies continue to develop and mature. This approach also allows our customers to have a base of "second source" components and upgrades constantly available."

According to Randy Freeman, vice president of marketing at Quad/Tech International (QTI) in Sussex, WI, all of the computerization that has gone into today's versions of web inspection and control systems has resulted in two improvements: better quality and lower waste.

"The printing industry is very competitive, and improved productivity is the most important issue for printers," Freeman points out. "One way to improve productivity is to be able to reduce on-press manning requirements. Automated controls take over processes that were previously controlled manually, allowing a press to run with fewer people and, therefore, a lower cost basis."

These advances in web inspection and control system technology are made possible due to the lower cost of computer-related hardware (hard drive space, RAM memory, etc.), and the greater power and faster processing speeds of computer systems available, says John Thome, vice president of marketing for BST Pro Mark in Elmhurst, IL.

"The digital camera has numerous natural advantages over analog technology," Thome councils. Some points he stresses include: more accurate color reproduction; insensitivity to ambient light and electronic interference; greater image resolution; faster processing of more information, which is essential for effective defect detection; smarter defect detection algorithms; the ability to filter out random variations inherent in the printing process; and the ability to desensitize areas of the web.

When printers are ready to purchase register controls or web inspection systems, Penny Shawah, customer relations manager with CC1 Inc. in Manchester, NH, says there are five points to consider: justification, equipment field performance, ease of use, vendor follow-up and support, and equipment reliability.

"Is the system they are considering going to save them waste in terms of time or money, or will it improve their product quality?" Shawah asks, rhetorically. "ROI analysis should be an important part of this decision."

As far as equipment field performance, Shawah suggests finding out what the equipment is doing at current installations, and if it is providing the performance that was initially promised. Also, she recommends finding out how well this equipment was accepted and used at current installations, and if it was easy for the press operators to learn and operate.

Check Their Rep

Manufacturer reputation and capabilities are also an important factor, states Thome, of BST Pro Mark. He boasts that his company has more than 10,000 web inspection systems installed worldwide, has more than 900 systems installed with automatic process control capabilities (color verification, bar code verification and defect detection), and has over 100 Genius systems installed.

"Customers retrofitting older presses are mainly interested in improving their quality to the highest possible level of precision," divulges Patel, of Innolutions. "On the other hand, the trend in newer presses is toward a larger number of print units per web. For example, The Hennegan Co. (Florence, KY) has just installed an eight-unit Heidelberg Sunday 2000 press and specified only Innolutions controls."

The number one item of importance for web controls is always repeatable and reliable performance, Patel continues. "If a control has to be fought every time it is used, the operators will not use it and the customer will ultimately be unhappy. The controls are designed to operate the way a pressman operates, and to do so under all possible conditions—and a few impossible ones."

Web Watchers

BST Genius Digital from BST Pro Mark is designed to be used as a visual inspection system, an automatic defect detection system, a bar code verification device, a real-time color monitoring system or any combination of these, in a single process control and management system. The product employs a modular design architecture, allowing true plug-and-play expandability, and the ability to readily customize every system to the user's specific needs. The basic product includes a comprehensive set of features essential for effective web printing and inspection—visual capabilities, virtual repeat technology, job save, positional memory and reference image comparison. Additional process controls (defect detection, color monitoring, register control, etc.) are added when the system is first installed or at any time thereafter.

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The CRC-610 automatic register control, available from CC1, provides fast, accurate digital color register control for side and circumferencial control of an unlimited number of colors per web side. One or two sides of the web, multiple web configurations, optional bindery control and cutoff control.

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From Eltromat Electronics, the AccuColor System measures the consistency of color throughout press runs and incorporates RGB camera technology for a non-contact, on-press color measurement system. Also available are WV2001 and WV4 web video systems with high-resolution viewing of the printed web, incorporating printed image color display on the monitors.

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The Fife InPrint system is a compact and economical video web inspection system. Its design makes it perfect for label press applications, delivering precise web monitoring at an affordable price. The single shroud strobe head (340mm height) contains all viewing functions; no separate CPU required. Contains integrated power supply for maximum illumination/minimum fluctuation in image brightness. Includes split screen and freeze frame modes, motorized zoom lens.

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ColorQuick on-web color control system, from Graphics Microsystems, combines a 2mm-high color bar with built-in recognition features and a proprietary, high-speed pattern recognition system to ensure color data accuracy needed to support closed-loop control. Verifies measured color patch before accepting information for press control and operator display. Reduces makeready and improves color consistency through real-time operation and data display. Color Manager provides printed charts and graphs with critical color data.

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Aquila, available from Hurletron Inc., is an IntraPress registration system that optimizes registration accuracy by placing the control action next to the sensing operation. Features PresSet, which places the press in gross register within three repeats.

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For color register control, Innolutions Inc. offers the CRC2000. This unit offers the latest technology utilizing wide field cameras and shape recognition. The operator controls the system through a flat-panel, full-color touchscreen. The user is provided with positive feedback for all inputs, so there is never any question about what the system is doing. All of the features are intuitive to any press operator, and accessed easily through large and clearly labeled buttons. Finally, the user is presented with statistical information to aid in determining that the press is working at maximum efficiency.

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Vision 2000, from Inspectron, can read and decode 10 characters per millisecond at full web press speed. Full-page inspection allows users to capture multiple fields, recognize and read data against variable-colored backgrounds. The eight-camera capability reads and decodes large amounts of information.

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PC Industries has developed the new RX Series digital web inspection systems. The system combines digital features such as automatic print defect detection, software image rotation, remote support and diagnostics, extremely compact camera head and absolute image positioning.

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QTI designed the RGS Vector register control system to meet the demand for high-speed register control in the printing industry. QTI's specially developed, CCD matrix camera can achieve up to 30 captures per second while the web is running at speeds up to 3,500 fpm. Camera functions can be preset with information obtained from the press controls or from the job storage library of QTI's ICON product platform. Preset functions include mark position based on press ink key positions, mark format and mark-to-register motor assignment.

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The CLC PLUS system from Web Printing Controls uses only one sensor head per web surface to perform both register and density functions. By having a 1⁄16˝ target bar, initial register alignment is critical, because the targets could be covered by the bleed. CLC PLUS finds and scans an initial register target to pull in register fast. The system then automatically switches to the 1⁄16˝ (.063˝/1.5mm) or 7⁄64˝ (.109˝/2.6mm) total white space color bar to adjust and maintain color density while correcting for color register simultaneously.

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