COLOR CONTROL Quadtech presents converters with an in-line reel control system, that automatically inspects and measures color. It is speedy and effective with a great variety of materials, minimizes start-up waste, guarantees accuracy in all production phases and reduces labor costs.
Randy Freeman
Thanks to the technology that enables the achievement of high speeds and rapid configuration changes, the most recent machines are lean production-, zero waste oriented. But without powerful and reliable control systems they cannot be exploited to the full.
For this reason the new generation devices are capable of fielding objective and standardized methods for measuring color parameters and for carrying out an accurate in-line inspection that do not compromise print machine performance.
What is more equipment is available that can handle the full variety of paper and film substrates, both transparent, supported, unsupported and reflective.
The advantages of in-line controls
In flexographic and gravure printing applications, an in-line inspection and color measurement system comprises a spectral sensor, a video camera, a lighting system, high-powered software to process the image, and central data repository to enable at-a-glance viewing of print defect information, registration and spectral data as well as communication with other systems in the workflow. The sensor and lighting are located after the final printing station.
This type of system provides a number of important benefits. Aboveall it enables ability to monitor quality throughout the production run for 100 percent of the printed web, not just at the end of each roll, at the same time eliminating much of human intervention. It also provides a stable and reliable means of monitoring quality and fast remedial action. Lastly, it enables preset color ratings to be attained more rapidly, thus eliminating start-up waste.
 The QuadTech SpectralCam™ delivers L*a*b* data for precise, cost-effective color management, in the image, in-line, on paper or film substrates. |
|
ColorConsulting distributes Quadtech in Italy QuadTech Inc. (inspection and color control systems) reinforces its commitment on the Italian print market and has chosen ColorConsulting Srl (Saronno, VA) as a sales agent focused on commercial and packaging.printers The relations between the two companies have been consolidated with the creation and integration of Color Quality Solution in the X-Rite InkFormulation, already distributed by the Lombard company.  ColorConsulting Srl, founded in 2001 with a focus on control systems and color management, offers consulting and training services, products and tests for the graphic arts industry to print buyers, traditional and digital printers and ink manufacturers. Its experts are actively involved in the development of TC 130 ISO standards and the company has recently created a division equipped to provide any kind of proof of conformity for the graphic arts industry regarding paper and ink. QuadTech, Inc. is a world leader in control systems for printing presses, with a presence in over 100 countries to the web offset sectors for commercial printing and newspapers, print machines for packaging and converting products and rotogravure presses for magazines. The company has branches all around the world, has achieved ISO 9001:2008 DNV certification and is a subsidiary of Quad/Graphics, one of the largest and most technologically advanced printers and processors of multichannel solutions in the
|
 QuadTech’s Web Stabilizer provides accurate in-line spectral color measurement on the widest range of packaging substrates, including paper, foil and polyethylene and polypropylene films. |
Video camera and illumination
The most updated systems include faster cameras to enable the latest generation of gravure and flexo presses to perform at higher speeds without compromising on quality. Recommended inspection camera resolutions are 250 dpi, although a maximum of 2500 dpi is possible; cameras must be able to detect defects from < 0.1 to 0.2 mm across the web, and 0.15 to 0.35 mm in the printing direction. The print width, the minimum defect size and the print speed are the factors that determine how many cameras are needed. To ensure a constant level of illumination on the area under inspection, a solid state system made up of white LED temperature-controlled, actively cooled lamps is used. Three lights are included in the configuration: a high-intensity top light for non-reflective and non-transparent surfaces; a low-intensity foil light for reflective surfaces and inks; a back light, both illuminating and providing contrast for transparent or semi-transparent substrates.
The details that make the difference
The inspection system of this type includes different aids capable of multiplying the overall print quality. For example to avoid the risk of corrugation a web stabilizer system enables color measurements on-the-fly on transparent, opaque or unsupported films or paper. The stabilizer consists of a flat-top, low-friction platform with two BCRA (British Ceramic Research Association) tiles: one black, measuring substrate opacity, and one white, measuring color.
On top of that, images of up to 2500 dpi can be captured and made available to the operator via the user interface. As a result a host of defects common to central-impression flexo such as pin-holing, bridging, doughnuts and halos, can be identified and immediately remedied.
What is meant by quality
The most recent in-line spectrophotometers are capable of measuring the spectral response needed to calculate the color values at max. speed, on the basis of a great number of points selected on the image (up to 72) and continuously. What is more the principle of the Golden Template is exploited: a master image that is captured by the inspection system when the press is running good copy. Every printed repeat is compared to that original Golden Template; it is also more sensitive to slow-growing defects such as register, streaking and color changes.
The PDF Verification software makes structural comparisons between the Golden Template and the customer-approved digital artwork file, alerting the operator about cylinder set-up or plating errors without the need for visual checks, and also resolves the problem of inspecting packages that include multi-language information or different alphabets. A fixed PDF reference eliminates the problem of emerging defects such as subtle color changes. Lastly, a central repository audits, stores and generates reports of both current and historical data, enabling trend analysis and defect traceability. Thus the QC control tools make all the necessary information accessible, enabling the storage of job settings and reducing setup times.
Randy Freeman
General Manager Packaging QuadTech
