the evaluated data are used to optimize the process, they can help to reduce ... control systems from manroland web syst
Fourth Step
Evaluation and Optimization Potentials of Color Measurement Technology
Finished productions provide the right conclusions to make following jobs more efficient. The target is not only to eliminate errors but also to improve processes that are considered as good. Many customers talk about a „learning system“. The PECOM-X PressMonitor therefore saves values from the prepress, the print run and the post-press to improve the quality. The module PressQualiy is crucial for the evaluation of the control systems. It collects measuring values about cut-off-/color register, fan-out, ink density and spectral measuring, evaluates them and visualizes the data throughout the production run. Due to this, management reports and analysis for Managing Directors can be easily created. This enables a reasonable handling of the operational procedures of a printing company. One question that is frequently asked by directors of printing companies is: “What is the ROI of the PressMonitor“. This can be answered as follows: if the evaluated data are used to optimize the process, they can help to reduce waste rates and reclamation costs. Due to this, the investment for the PressMonitor amortizes very quickly.
Potentials of Color Measurement
Conclusion The precise measuring technology from grapho metronic, combined with the control systems from manroland web systems, offer the best technological solutions for the color measurement during the print run. This requires more than just adding a measuring system to a printing press. manroland web systems sees itself as a process owner. To provide these control systems, the complete knowledge from engineering, electronics, software development, process- and measuring technology is needed. This is the basis for best printing quality and a maximum of cost savings.
Four Steps to an efficient Color Control
The Authors Manuel Kosok is Managing Director at grapho metronic Mess- und Regeltechnik GmbH in Munich since the middle of 2014. The company that is specialist for color measurement provides cameras and software for offset printing presses. Dr.-Ing. Gregor Enke is leader of the department for development and technology at manroland web systems in Augsburg. As one of the innovators of PECOM-X, he is fascinated by the entire printing process and its constant improvement. The target is to get the optimum out of the existing mechatronics (engineering, electronics and software development) at manroland web systems. Furthermore, all this shall be combined with the best processand measuring technology to achieve the best possible customer benefit.
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The PressMonitor shows the tonal value increase at the 40% grid over time. Incidents at the press, like reel change (green) and blanket washing (blue), are additionally displayed.
Contact:
Contact:
Dr. Gregor Enke Vice President Development and Technology at manroland web systems www.manroland-web.com
[email protected]
Manuel Kosok Managing Director grapho metronic Mess- und Regeltechnik GmbH www.grapho-metronic.com
[email protected]
manroland web systems GmbH Alois-Senefelder-Allee 1 86153 Augsburg Fon: +49 821-424-0 Fax: +49 821-424-3303
[email protected] www.manroland-web.com
© manroland web systems GmbH, 010/2015
www.manroland-web.com
First Step
Presetting is the Key
The calculation of the startup curve includes the following issues: Two curves for ink and dampening solution Different ink-/paper combinations
Initial calculation of press specific startup curves, due to a standardized procedure
Potentials of Color Measurement Technology
Potentials of Color Measurement Technology
The following keywords that appear at expert talks need to be classified: Color metrics, ΔE, spectral mesuring technology, imagebased measurement Some providers of color measurement systems suggest that it is possible to do a spectral measuring with a simple RGB camera. Based on these values, XYZ- or Lab-values shall be possibly determined. This is a dubious approach, as the visible spectrum of 380-788nm cannot be measured with three RBG channels. A precise spectrometer in this case needs at least 256 channels. The InlineSpectral Control that has been developed by grapho metronic and manroland web systems meets this demand.
There is one statement that is a result of many projects: “Thanks to the new color control system, we can save 50% of waste.” And he who looks closer, often recognizes that the installation of the color measurement technology has not been the only improvement. The commercial and newspaper presses that have already entered their advanced years, have also got equipped with a complete control system and control desk retrofit. An update of the presetting functions additionally improved the waste rates significantly. But even the best color measurement system for itself cannot perform miracles when it comes to waste reduction. When the target is to achieve a waste rate that is less than 50 copies for each print run like this is a fact for the COLORMAN e:line in Bamberg, the pre-settings of the press control have to be optimized. What is essential is the startup of the press. There is no doubt that the system can provide a fast measuring. If more ink is put to the inking unit, there have to be up to 200 circulations until the ink reaches the paper web. Therefore, a perfect presetting is half the battle for low start up waste. Regarding this, especially the startup curve for color and dampening solution is crucial. This means per definition: “A change of the press speed needs a dynamic and rotation speed dependant metering of ink and dampening solution.”
Third Step
Ink Zone Control
Potentials of Color Measurement Technology
What is the right technique to solve the tasks that are given at the color measurement? There are four steps that can be considered as essential: presetting, color measurement, cost reduction and evaluation.
Second Step
Startup curves
The screenshot shows an editable startup curve at the control desk for the ink at the printing unit for black color. Every percentage value with reference to a particular speed is displayed. The actual speed of the ductor is calculated from the maximum speed of the ductor and the curve value for the relevant speed. InlineDampening Control The InlineDampening Control is an extension of the presetting due to startup curves. This inline control system proactively adjusts the supply of dampening solution to the temperature conditions at the printing plate. When the press is shut down for a job change, the temperature of the plates and the blanket cylinders rises, what causes a larger amount of water, needed for the print run. The control system automatically increases and reduces the water supply – even for a decreasing temperature during the production.
In addition, Lab-values cannot be easily converted to CMYK. A color coordinate at a Lab system can be achieved by many different CMYK combinations. This is for example how ink reduction or UCR programs work, which intend to reduce the CMY-parts due to a higher K part. Yet in mathematics an equation with three known variables (Lab) and four unknowns (CMYK) can be hardly solved. Therefore complicated matching scales and a connection to the TIFF data from the prepress are provided for image based measuring. However, for having a mathematical basis, all ink-paper-combinations of the press have to be printed and measured, what causes an immense effort.
“The resulting developments are called micro marks and full spectral measuring.” It should be noted: The only thing that can be manipulated by the operator with regards to color optimization during the print run is the dosage of ink and water. Here, the direct link from measuring the ink density leads to ink quantity and therewith to the ink zone adjustment. For newspaper printing, the resulting developments for color measurement are called “micro marks” for commercial printing they are called “full spectral measuring”. IDCµ for Newspaper Printing With more than 4,000 delivered measuring heads and decades of experiences in control systems for commercial printing presses, the IDC technology will now be transferred to newspaper printing. The measuring takes place based on micro marks (≈ ≤ 0.6 mm diameter) for each color and all ink zones. With IDCμ, the printer can do all setpoint adjustments completely automatically at the control desk. All necessary job parameters are taken over by the PressManager.
Besides the precise measuring systems and effective control systems, it is a real customer benefit to reduce costs. Therefore the following examples are given:
2,5
2,0 Density 1,5
1,0
0,5
0
0,5
1,0
1,5 2,0 2,5 color coat size [micrometer]
At the unsaturated area, density and color coat size are almost linear, dependent from the ink. Therefore, a direct relation to the ink slide is given.
IDCµ: the inline ink density control with micro marks from manroland web systems provides best quality for newspaper printing.
The InlineCutoff Control (ICCd) provides an optimized cost-per-copy due to paper savings. This cut-off control leads each product directly to the folding knife, copy by copy, and readjusts if necessary. Due to this, every print sheet can be cut and folded individually and exactly. Therefore, the cut-off control uses the measuring cylinder at the folder. It measures every copy with a measuring frequency of 20 Hz what means up to 70,000 c/h – during its lead to the folder. Due to this, the ICCd can record every circulation and readjust the drives for the folder tracking. This results in small and medium tolerances at the cut-off register throughout the production. A precondition is the usage of the original drive system from manroland web systems. Thomas Horst, Managing Director at the huge German heatset and newspaper printer WEISS Druck, numbers the savings potentials of ICCd: “The greatest benefit is given by waste savings. The costs for this could be reduced by appr.70,000 EUR p.a. The investment pays out in just one year due to this savings.”
Printers additionally talk about: increased product quality longer cycles between washups ink savings at the production increased process stabiliy transparency for the process status waste savings
“Single entry of data and system integration are the keywords.“
Cost Savings Right Down the Line tions of the lighting at the measurement optics. This measurement system is able to control color register and fan-out. In the future, the IDCμ sensor will also be able to control the water supply. IDC for Commercial Printing At the commercial printing, real density values are supplemented with real spectral values. The full spectral measurement “InlineSpectral Control“ (ISC) is an expansion of the InlineDensity Control. It enables a highly precise, resilient measuring of the color coordinate at full production speed. With 256 measuring channels, the InlineSpectral Control reaches a significantly higher measuring resolution than other available systems. Due to the highly precise measuring of the color coordinate, print samples can be automatically checked regarding their conformity with valid ISO-standards. The combination of real density values and real spectral values (incl. Lab and ΔE) helps to control the press ideally. Thus, it can be observed that when the density varies, the ΔE improves or degrades. Following, the control systems keeps the values on a constant level at the optimum zone. If the focus lies on saving ink, tolerances can be set differently and a higher ΔE can be permitted.
“The combination of real density- and spectral values helps to control the press ideally.”
Technology of IDCµ The cameras from grapho metronic are equipped with CCD-sensors. They are designed for a high dynamic range and can provide a precise measurement of ink density discrepancies thanks to polarization filters. The lighting is matched durably with specific standard filters via LEDs and appropriate color screens. The measuring is carried out with a 45-degree-geometry conforming to standards. The print sample is illuminated at a 45 degree angle and monitored by the sensor with 0 degrees to therewith avoid direct reflec-
Reducing Costs
Print materials, like e.g. paper with an optical brightener, are a challenge for many printers. They are “exposed“ by an additional UV-stimulation during the measuring. Thus, the ISC measures with measurement condition M1 including a specified UV-part. The quality documentation furthermore allows an integrated material check of ink and printed paper. If the paper manufacturer changes the material, the control system PECOM-X will detect this at the displayed color measurement values and keep it in record.
Increasing the productivity is another essential aspect for reducing costs. The key words for this are “single entry of data“ and “system integration”. The operator generates the print job at the PECOM-X ProductionPlanningManager. Therewith, all necessary data for the production is given. The operator at the control desk becomes more and more just an „observer“. This is caused by the reliability of the presettings and the control systems, which help to reduce necessary interventions of the operator. If adjustments e.g. for the set density, should be necessary this can be done directly via the ink zone keyboard. Due to this, the productivity and the efficiency regarding resources increase.
The cut-off register camera
